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Firemantlaval RateCareer Course.Naval Education andFla.'NAVEDXRA-10520-E76248p.; Photographs will not reproduce inmicroficheSuperintendent'of Documents, W.S. government PrintingOffice, Washington, D.00.20402/(Stock Number0502-LP-052-6010)

Traiang.Manuil and Nonresident

Training. Command Pensacola,

MP-$0.83 HC-$12.71 Plus Postage*'DESCRIPTORS, *Engineering;.*Engineering TeOhniciAns; Engines;

*Equipment Maintenance; Fluid,tower Education;Hydraulics; *Job Training; Manuals; *OccupatidnalInformation;'Ocean Engineering; *Study Guides

IDENTIFIERS *Navy

ABSTRACT., The Rate Training Manual and the Nonresident Career

CoUrs0 OWNRCO-was prepared to assist the fireman apprentice togdalify and to advance to fireman in theNavy. The Manual is designedfoVi.ndividual study and. provides subject matter that'relatesdirectly the occupational qualifications of the fireman rating.Fireman is one of the lower ratings in the eng4sering department,which is organized for the efficient operationiMMAntenance, andrepair.of the ship's propulsion plant, auxiliaty,Michinery, and.piping systems. The areas covered inclmdell(1),administrative andoperational functions of the engineering departMent; (2) various laws.t.andjAlenomena of nature related to ongineeringfundamentals; (3)TprinciVles and types of ship propulsion; (4) areas of operation inbasic steam cycles; (5) operating principles. of boilers; (6)components of 'the steam ;turbines and reduction gears; (7) location°Eind'function of auxiliary machinery and equipment; (8) measurement%instruments;-.(9) pumps, valves, and piping; (101 diffeient shipboardelettrical eqmipment; (11) internal combustion engines.; and (12)engineerihg watches and duties. A glossary of engineering terms andthe metric system are appended and an index is-imcluded. A series ofsix assignments is provided in the NRCC to assist the student throughthe training manuals (Author/BC)

**************************i********************************************* Documents acgeed by ERIC include many informal unpublished ** materials,not ava lable from othersources.,ERIC makes every effort ** to obtain the best copy available. Nevertheless, items of marginal. **'reproducibility are often encountered and-this affects the quality ** of the microfiche and hardcopy reproductions ERIC makes available **viathe.BRIcDocumentReproduction Service (EDRS).,EDES is not ** responsible for the quality' of the original document. Reproductions ** supplied by BURS are the best that can be made from .the original. ************************************************************************

O

FIREMANJUL 0 1 1976

NAVAL EDUCATION AND TRAINING COMMAND

RATE TRAINING MANUAL

AND NONRESIDENT CAREER COURSE

NAVEDTRA 10520-EU S OEFARTMENT OF HEALTH.

EOUCATION IL WELFARENATIONAL INSTITUTE OF

EOUCATION

THIS DOCUMENT HAS BEEN REPRO-DUCED E RACILY AS RECEIVED FROMTHE PERSON OR ORGANIZATION ORIGIN.ATINr, IT POINTS Or VIEW OR OPINIONSSTA TEO DO NOT NECESSARILY REPRE-SENT OFFICIAL NATIONAL INSTITUTE OFEOUCATION POSITION OP POLICY

1111 PREFACE

This Rate Training. Manual . arid the 'Nonresident Career Course(RTM/NRCC) has been prepared to assist the Firemen Apprentice to qualifyand, to advance to Fireman. Study of this training manual should becombined with practical experience, with study and review of other

applicable Rate Training Manuals, and with study of manufacturers'tecloical manuals, NavShips Technical Manual, and other applicablematerial.CrDesigned for individual study and not formal classfoom instruction; the

RTM provides subject matter that relates directly to the occupationalqualifications of the Fireman rating. The NRCC provides the usual way ofsatisfying the requirements for completing the RTM, -The set of assignmentsin the NRCC includes learning objectives and supporting items designed tolead students through the RTM.

As one of the Rate Training Manuals, Flreinani and the NRCC has beenprepared by the Naval Education and Training Progam Development Center,Pensacola, Florida, for the Chief of Naval Education and Training.Information provided by numerous manufacturers, publishers, andassociations is gratefullk acknowledged. Technicatiassistance has beenprovided by the Naval Sea Systems Command, Servi0 School Command,San Diego, and the Service School Command, Great Lakds.

Revised 1976*

Published byNAVAL EDUCATION AND TRAINING SUPPORT COMMAND

o

Stock Ordel3i ng -No.0502-1.14, 2-6010

UNITED STATESGOVERNMENT PRINTING OFFICE

WASHINGTON, D.C.: .1916

THE UNITED STATES NAVY

'GUARDIAN OF OUR COUNTRYThe United States Navy is responsible for maintaining control of the seaand is a 'ready force on watch at home and overseas, capable of strongaction to preserve the peace or, of instant offensive action/to Win in war.

It is upon the maintenance of this control that our country' gloriousfuture depends; the United States Navy exists to make it so.

WE SERVE WITH HONOR

Tradition, valor, and victory are the Navy's heritage from theigtist. T.othese may be added dedication, discipline, and vigilance as the wathhwordsof the present and the future.

N Athome oron diStant stations we serve with'prideeconfident in the respettour country, our shipmates, and our families.

Our responsibilities sober us; our adversities strengthen us.

Service to God and Country is our special privilege. We serve with honor.

THE FUTURE OF THE NAVY

The Navy will always employ new weapons, new techniqueS, andgrotter power to protect and defend the United'States on the sea, 'underthe Seaj and in the

Now and in the future,' control of the sea gives the United States hergreatest advantage for the maintenance of peace and for victory in war.

,

Mobility, surprise, dispersal, and offensive power are the keynotes ofthe new Navy. The roots of the Nally lie u a -strong belief in thefuture, in continued dedicatiorito our tasks, and In reflection on our,

heritage from the past.

Never have our opportunities and our responsibilities been greateil:

CONTENTS

CHAPTER

1, Prepafinglor Advancement

2. Engineering DepartmentIV 4

4

Page

1

3 Engineering Fundamentals , . ' i." 174

'4, 'Ship Propulsion . . ..., . . . . . 31

5 Basic Steam Cycles . { ...f. . . .. 48

6. Boilers . . . le

, v. 4 .1. , 56

7. Steam Turbines andIeductioI

h Gears 72

8. Auxiliary Machinery and Equipment 88

9. InstruMents '.... . . .... . .. . . .. . 4 4 4 100:

10. Pimps, Valves, and Piping . ., . 116

1 1 . Shipboard Electiical Equipment ... .. . , . 143it ti .

12. Internal Combustion Engines . . 156

13. Engineering Watch4 . . . . 171

APPENDIX

I, GlossaryEngineeri4 Terms

II The Metric System .

INDEX

Occippational Standards . * . .

Noniesident CarPer Course followS Occupational St dards

177

1.0

193

'197

'CREDITS -

The illustrations indicated below are included in this edition of Firemanthrough the courtesy of the designated . companies, Diu rs, andassociations, Permission to 'use these illustrations is gratefully ac owledgectPermission to reproduce these illustrations and other materials in . thisPublication should be obtained from the source.

Source

Babcock & Wilcox Company

Figure

6-16C

Buffalo Meter CoMpany 9-16, 9-17

Cooper-Bessemer Corporation 4-12

Crane CompanY 10-15

Ciosby Valve & Gage Corripany 9-6

General Electric Company 7-14, 7-15, 1 .2, 11-3

General, Motors Corporation 12-6

Detroit Diesel Engine Division 4-13

Electro-Motive Division 4-8

James Go Biddle' Company 9-21, 9-22

Jones Motorola Company 9-20

Manning, 'Maxwell & Moore, Inc. 9-1, 9-2, 9-3, 94, 9-5

U.S, Naval 1nStitute 54, 7-5, 7-6, 7-7, 741, 7-12,7-13, 7-16, 8-5, 8-6, 8-7,8-8, 9-7, 9-8, 9-11, 9-12,9-13, 9-23, 10-9, 10-16,

Westinghouse Electric Corporation

1V

10-17, 10-24, 10-27,10-28, 10-29, 10-31

5-3, 7-10, 9-19

....... .

PREPARING FOR ADV

Study of this training manual will start yoUon your way to earning one of the Engineeringand Hull ratings, (See fig. M.) This trainingmanual is one of several which will, help youmeet the technical requirements foradvancement.

As a member of the engineering departmentaboard ship, you know that you are assigned tothe heart of the ship. It is through your efforts

e e ortsit f every other member ot,theePattment that ur ship beconies 'alive and isle to meet its .'co mitments anywhere on the

oceans of the world,

RATE OF FIREMAN

A Fireman" is basically an engineering trainee \who must perform a wide variety-ottasks. Some N.Jof these tasks may seem quitennnecessatYalthough there is a very distinct reason for thetasks you will be required to perform. Thereason, even though it sometimes may be 'unclear, is to increase the operational icklinessof the ship and tb further your *ping.Everyday throughout your Navy career, y it willlearn something new to'increase your, kno edgeand to make you more valuable to yoursel, andto the Nail,.

You .must be able to .serve as: a competentassistant to the petty officers holding any of the10 ratingi-ii,.!the engineering department. (Theseratings are discussed in chapter 2 of this trainingManual.) YOu will learn to operate pumps,motors, and turhiiies; to read gages and .

thermometers; to maintain and clean eng,ines,'machinery, and compartMentsi and to identify

,refrigeration equipment, anchor. windlasses,

distillin plants, and mpressots. You will berequire to perfOrm entive correctivemainte 'ante in accord ith th -M system.(For, ad itionalinformatio On this stem, :referto Base Military Acquirements, NAVEDTRA10954- Chapter 16.) YoU will also' standsecurity and fire watches in engineering spaces,act as boat engineer, take part in drills, andperfo the duties'," of damage control repair

arty te ephone-talker and messenger. . .

You .may ask yourself the question, "flovi'am I ev r going to learn to do all these jobs?" In'the. beginning, you Will work with the iiettyofficer Who is responsible for seeing that aspecific job 'is done properly. He will show youexactly how to perform every detail of eachoperation. Then he will have You' do the jobunder his supervision, Finally, when he hasconfidence in you and your ability to do thejob, he will give you the opportunity to performon your Own. This general procedure' will beobserved thronghout your entire period as astriker, I

In addition to 'meeting theie requirements,you Will? also:' be required to have, a basicknowledge of mathematics and. blueprintreading. Sources of information which will beuseful in learning about these subjdcts are listedlater in this chapter.

ADVANCEMENT ANDELIGIBILITY REQUIREMENTS

'Before you candvalice in rate, you mustfulfill certain litary and professionalrequirements.

. Naval requirements for advancement are,those general standards applicable tb all enlisted

FIREMAN "s

FIREMANRECRUIT (FR)

FIREMANAPPRENTICE (FA)

FIREMAN(FN)

a

0.

fr MACHINIST'SMATE "(MM)

MACHINERY , BOILER-REPAIRMAN (MR) TECHNICIAN (BT)

/1111.% III 1 11

ENGINEMAN (EN) ELECTRICIAN'S BOILERMAKER (BR).MATE" (EM)

AIL

HULL MAINTENANCE MO ER (ML)'TECHNICIAN

(HT)

4k

PATTERNMAKER(PM) .

I. G. CTRICIAN (tC)

y.

YSGTAESM TECHNICIAN(OS)

Figure il.Engineering and Hull Ratings.

2

3.10

Chapter' 1--PREPARING FOR ADVAlsICENTpersonnel, such as watch standing, first aid, andmilitary conduct. You must show that you areproficient in each of the naval standardsspecified for the next higher pay grade. Theseare discussed in Military Requirements,NAVEDTRA 1054-D.

Professional reqtiirements for advancementare technical standards ,,that are directly relatedto the work of each rating. -.. .

Both the naval. ;requirements and theprofessional -requirements are divided intosubject matter gsoupi, which are further.subdivided into practical. factor&and knowledgefactors. Practical factors are things that youmust be able to do. Knowledge factors are theminimum things you suit know in order toperform your 'duties.,The p ofessional and naval requirementS justdiscussed re listed in the Manual of, NaVyEnlisted M npowerand Personnel Classificationsand Oci.upational Standards, NavPers 18068-D(with changes).:Aii&4 manual provided theminimum requipments for adVancement to eachpay de within each rating.

:The .- , ards for Fireman form the basis forthis man al a d they were current at the date ofthis prin g. However, the standards 'changeoccasion ly, and the questions in theadvancement aminations for all pay grades arebased on the latestlevision. Consequently, longbefore taking an examination for advancement,'you should 'Cheek fOr revisions.' and\ assureyourself that your knowledge covers 411 thelatest standards.

A special form known as the RECORIOFPRACTICAL FACTORS, NAVEDTRA 1414/1,is used to keep a record of your practical factorstandards. The form lists all practical factors,both military and professional. As youdemonstrate your ability. to perform eachpractical factor, appropriate entries are made inthe DATE and INITIALS columns by thedivisiOn officer or your dupervisini petty officer.Since changes are made periodically to theManual 441,,f Navy Enlisted Manpower andPersonnel Classifications and ccupationalStandards, revised forms . of NAVEDTRA1414/1 are provided wit* necessary. Extraspace is provided on the Record s:3f Practical

Factors or entering additional practical fa, ors. as the y'+ are ,published in changes to . theOccupational Standards Manual. The Record ofPractical Factors also provides space forrecording demonstrated proficiency in skillswhich are within the general ctf the ratingbut which are not identified 4 minimumoccupational standards.If you are transferred before you quaff inall practical factors, the NAVEDTRA 1414/1 isforwarded: with your service `record to yOur next-duty station,. You can save yourself a lot oftrouble by making sure that this form is actuallyinserted in your service retard before. you aretransferred. If the (Om is ,not in, your servicerecord, you may be required tci ,start all overagain and requalify in the practical factors which. have already been checked off,The Navy has established certain'requirements 'that mpst be met before you areeligible, to take the examination foredyancement. You must

,

First: Meet basic requirements; such aslength of service in pay grade and total service.Second: Have a statement in your servicerecord that you satisfactorily 'performed the,practical factors for` the next higher pay grade.'Third: Have a statement in your service. record that you successfully completed thetaking manual for the next higher level ofadvancement.,, ,- Fourth: Be recommended by yourcommanding officer.

When you satisfy all of these requirements,you are eligible to paiticipat in theexamination.. If you pass the exa tion with a .high enough score, your command' g officer has, the authority toadvance you in rate. '1,

4.

SOURCES OF INFORMATION

The Navy has set definite .limits on thematerial for which you-are accountable on theexamination. The sources from whithexamination items are taken are listed, in theBibliography for Advancement, NAVEDTRA10052. This bibliography is available on yourship or station. It is revised annually, so he-sure

FIREMAN,

to consult the current edition. it provides the

titles of Publications and sections of

publications that you shOulk study when

preparing for the examination. TI% publications

lisfed contain material covering all,the standards

listed in the Occupational StandarckManual. An

asterisk (*) identifies the training manual or

manuals that you must complete before you can

be eligible to take the examination for

advancement;One of the most useful thinks your an learn

4 about a subject is how to find out More about it.

No single publication can give you all the

information you need. to know to perform your

duties. Basic training manuals which' 'be

helpful to you as you .prepare for 'advancement

are lifted below. your petty officers will assist

you in obtaining other sources of information.

Tools and Their Uses, NAVEDTRA 10085-B

'- Sr

itEWARDSOF ADyANCEMENT

Each time you advance, you receive many

rewards. These rewards include higher pay and

allowances together with additional pension

benefits when you retire, But the really

inportant gainS are oppo tunities for more .

interesting and challenging assignments,

increased respect from your Superiors as well as , .

from the men you, supervise 'or help, and th;Chance for greater fulfillment of your abilities.

Above all,,, you are afforded the opportunity to '.

Serve your conunancl, your ,Wavy, and your

country at a higher level of responsibility in a

more important job.As a men:theta:the United States Navy, you

have the satisfaction of knowing that, as you

advance, you are serving your country in .a most

important way. Do your job well at all times,

and take pride in what you do and hoW you do

it. Service to your country is a special privilege.

You must make every endeav ?t to serve with

honor. ,'.

Tradition, valor, and victory are the Navy's

heritage. The long history of outstanding

achievements and 'noble service of. the Navy

provide an inspiration and a challenge to you

and your shipmates. It is up to you to help

maintain and enlarge the , prestige and thetraditions of the naval service. ii:r.1

BluepriNt Reading and Sketching,NAVPERS 10077-13

The glossary section in the Appendix of this

training manual is another good source of

information. Unfamiliar` or difficult to

understand engineering terminology which has

been use throughout this text is defined in this

section.

°le

1

10

CHAPTER'2

ENGINEERING DEPARTMENT

,'The, engineering, ratings cover alrphases of "

-operation, maintenance, and repair of maehineryand equipment under the cognizance (continDof the engineering department. To fullyunderstand the nature of your new assignmentsas a Fireman, you must understand theorganiza f the engineenng department andbe familiar with the scope, of each., Group VII(Engineering and Hull) Rating. .

In thin,, chapter we Shall discuss theadministrative and operational functions of theengineering _department .and the GroupRatings.

ORGANIZATION OF'ENGINEERING DEPARTMENT,

The engineering department is organized for-,

the efficient operation, maintenance, and repairof the ship's propulsion ,plant, . auxiliarymachinery, and-piping systems; In addition, theengineering department is resPonsible'for (1) thecontrol of damage, (2) the, operation, andMaintenance of electric , ',generators and -

distribution Systems, (3) repair to the ship'sand (4)1or general shipboardretiairs.

The organization of the engineeringdepartment is established by the 'slip'sOrganization book,, This organization is made upof a number Of divisionS whose functions..arediscussed laterin this chapter.. ,

The organization of the departinent will varyaccording to .the size of the. ship apii the'engineering plant, Forces 'afloat, ;areprimarily concerned with repairs, ; will hiverepair department consisting of MAO of theengineering ratinT, in addition totairienginiering

department which will concerned with theoperation and maintenance ','of' the propulsionPlant of the repair ship or, tender, Smallephips,because of the smaller number-of engineeringratings abOarcl, .will Combine many ratings into asingle division, . ,

Figure 2-1 shows.the organization structureof the engineering department aboard a lar$0ship and the functions 011ie various divisians ofthe 'department,- ,-Remember; that thisorganization .does not represent a particular typeor, class of ship. It 'should 'be ,noted that theadministrative assistant, the department trainingOfficer, and the special assistants arenicles to, theengineer officer and these' responsibilities, areoften 'assigned as ,additional duties" to officers,functioning in' other capacities at any. of thelevels in the direct chip of command.

Thethreeprincipal assistants to the engineerofficer age the .main .proprilsion assistant, thedamage, cOntror assiStanty; and the' -electrical -officer.; Each, Of-;'lliest ;.'aSsiatants, '- in' 'turn,adrainisterS those' divisionS!assignedna,hrdicated,on the Organization :chart':

The division, officer is -rtispansible, for the, Organiza "on of his division; The Watch, Quarter,and $ta 'o ill reflects the organization ofdivision by sec ores and shows ,the ,assignmentsfor all einergen4 d The -billets-, asSigneddepend upon the comp Merit ;the:divisionand the capability of-Personnel assn d, to the'. -

ENGINEER OFFICER

The engineer officer.'..isi, the head. Of thei e,,itiOe,:eringdepartMent.,, 'addition' to ,the,duties of idepartinent head, the' engineer officer

4,

'.SPECIAL ASSISTANTS,

ENGINEERING TRAININGOFFICER 'FIRE *ORAL..GA$'FREE ENGINEER

4, NBC DEFENSE OFFICER

_ 1

AriAGE cottrwill,4ststAto

R DIV' , A btVOFFICER- , OFFICER

ASSISTANT, .

.responsible the 'Operati*,...oare;, -arts'maintenance '411.444)P4Isioil. ' au&Ogehhiefyl the control :,of " damage .,'and,accomplishment 'Of pairi:itithin AhoT'aUPiOity.of 'the shops' :i',-the, eugineeFiUg

and respon sibilities; cif the',Ogineer,'Offieci 00,shreri ';14$,('', ostavi jZiguldtions!,` and

f%),iga#11;#1an finctRegyfrOfi fonirk(000 CL,, r

ft

DttoAitNENt.-AitgaNOTRAilyE-.,,,. A400

administrativefunction "as 'an" ide 'to the :010k0ei,' dtkir

anddOtiel'aie,as follO*az

` I

TO' s Pet;ise 00' :',opera tiOn "of, cthe, deP4n di4sutigioofic4, ensuring the

:;assigned: office:spaces:A*1 'the' cafe, rid upkeep of, office equipliente ,

2. To and ,direct thedepartment Ye,OUiph,,

screedfooted_ to ,onaiteCr -6,ffitia4 and initiate

iiotiou,Whitt:upPropritite to screen andensurecPP`Os*Iliclance.

xu prep Lion 'orepartmeilt-.0itectiyeaaM;Idlloiring,Telea*bY,'

the engineer' i fficer ekiitisi'eoritrol-hveflheirisskianpef..z':

de0qtiteut.'ke6i4s",i14(1,1010:', fickler fib790

.

Chapter 24ENGINBERING DEPARTMENT

6. To coordinate the preparation of thedepartment in-port daily watch hill.

7. 'To assign itasks to, and evaluate the'Performance ofclepartment Yeoman and otherenlisted personnel assigned to the departmentoffice. °

hi an engineedng derctinent where anadministrative assistant billet is not 'providedwithin the framewor of the ship'seorganization,the engineer officer, may elegate the duties ofsuch a billet to co ten !son. pi-

DEPARTMENT'TRAINING. OFFICEIV

The-duties of a department training Officerare generally performed by the engineer office/1or an assistant to the engineer officer. Some ofthese &dies are: '1"

I. To' develop a department yam .

program in support of -the training objectivethe ship. . T

2. TO implement approved*Itrainini plansAnd policies within the department.

3. To elfrrco,ordinate and assist in theadministration, of division training programswithin the d6partment, including: (a)supervision/of the preparation of trainingmaterials and review of curricula, trainingcourses, and lesson plans; (6) assist in theselection and training of instructors; (c)observation of instruction given.. at drills, onwatch, on ,station, . and., in the classroom,followed .by recomendaVons to the engineerofficer;.. (d) procurement; through the ship'straining officer, of required training aids anddevices includinVIms, projectors, training`courses, and books.

-

4. To maintain depk.rtvnt training record.,and training reports.

5. To disseminate 'information concerningthe availability of fleet and service schools.

e6, To initiate requisitions for training "i

plies and materials, subject to the approval ofengineerRfficer.

1111'X.;

MAIN PROPULSION ASSISTANT

The main .propulsion 'assistant is responsible,under the engineer officer, for the operatjo$care, and maintenance of the ship's propulsionmachinery and related auxiliaries, ff4 hascognizance Oyer the care, stowage, and use of'fuels and lubricating oils. The preparation and.care ..of the Engineering ,Log and Bell Batik arethe responsibility of the main propulsionassistant, as is .the preparatiof of operation, andmaintenance records and procedures.,

Machinery Division

If you are assigned to the M division, youwill 'probably work in one, of the'enginerooms.Normally, there is one engine for each of theship's propellers. On ships with two or moreenginerooms, 4;,1the engineroorns are generallylocated immediately aft of the firerooms whichsupply theni with steam. In an emergency, any.engineroOm can be isolated while the ship,continues underway on the remaining engines.

The B division operate's the boilers and theauxiliary fireroom machinery. if you areassigned to this division, your duty station maybe one of the firerooms. The firerooms areusually lb ed amidships on the lower levels.There ma be as many as 6 or 8 firerooms,depending n the size and type...of ship. In shipshaving more than one ffferoereach fireroomgenerally has two boilers installed either facingeach other, or side by side. The boilers are soarranged that any -number of them can be usedto 'supply steam to- the ship's engines. The'-firerooms are separated by watertight bulkheadsso that any fireroom iliay be paled off while theship operates-on the remaining boileri.

On your first trip though 'the fireroom youmay wonder why there are so maim/ lines andvalves: You will become familiar with a few ofthem at a time, and by paying strict attentionyou,, will gradually learn how all of them areused.

Steam, water, fuel oil, or air may be carriedin these lines. The lines which carry steam orwater are covered by insulation and lagging for

FIREMAN

personnel' safety and to prevent heat loss andcondensation. Lines are stenciled to indicate thefluid carried and the direction of flow.

These lines do not run through the ship at,random, but connect the units of the systemsaccording to a definite plan. In the course ofyour training you will trace these lines from oneunit to another throughout each system. The'ship's blueprints and drawings are of particularvalue in tracing out systems in the engineeringplant.

DAMAGE CONTROL ASSISTANT

The damage control assistant is responsible,under the engineer officer; for the preventionand control of damage, including control ofstability, list, -and trim. Conditions of-closure,watertight integrity, and compartment testingare carried out under his supervision. Thedamage control assistant (DCA) administe0 thetraining of the ship's personnel in damagecontrol, firefighting, emergency. repair work andnonmedical defensive measures against NBCattack. The hull maintenance shops and themachine shop are under the cognizance of theDCA. In these shops, all necessary repairs to thehull and the ship's b9ts, within the shop'scapacities, are made by' 14-assigned personnel.

Auxiliary Division

Personnel of A division operate therefrigeration plant, air compressors,. emergencyfire pumps, emergency diesel generators, and theventilation, heating, and air conditioningsystems. They are the boat engineers in smallboats and maintain the ship's steering engines. Ifyou are assigned to this division, you may bestationed in the auxiliary-SOces or in any otherpart of the ship where the auxiliaries under A-division are located. -

The refrigeration plant, similar in manyrespects to the home refrigerator preserves thesupply of fresh foods and provides ice forgeneral shipbOard use.. .The air compressors,supply compressed air for pneumatic tools, forcleaning parts of machiriery, for diesel engine airstarting systems, and for various other purposes.The equipment assigned to the A di.v4ion islocated throughout the ship.

Repair Divisioniii

The Rilivision is responsible for maintaining .

the watertight" integrity Hof the ship, The itdivision consists of the hull maintenance shops,If you are assigned to this division you will workin one of these shops.

All 'damage control ' and firefightingequipment aboard ship is maintained by the Rdivision. Much of the training of petsonnel indamage control is carried on by R. divisionpersonriel,

ELECTRICAL OFFICER ./

The electrical officer is responsible,. underthe engineer officer, for the operation,maintenance, and repair of the electrical,machinery and,systems throughout the ship. Themaintenance. of the ship's power and lightingsystems is the primary concern of the electrical "

officer. Repair shops are provided on larger shipsfor extensive repairs to eleCtrical equipmentThe IC system, under the electrical officer, is \apart of the E division.

The E diirision -has charge of generators,gyrodomOasses, intercommunications, and' otherelectrical equipment. The generators in theengjneroonis provide electricity for power andlight. The steam turbines. Which drive thegenerators are operated by 'the . ivision: Onelectric-driven ships, the E division so operatesthe main, generators and main ele trio motorswhich turn the ,shaft. If assigned to this division,you 'might work in the Main motor rooms, theenginerooms, the electric repair shop, or in theIC rooms.

NBC DEFENSE OFFICER

i Since nuclear, biological, and chemical (NBC)defense procedures are classified and subject tofrequent modification, it is best to refer tocurrent OpNav Instructions for a detaileddescription' of the NBC defense officer's duties..In general, the NBC defense officer (collateralduty of the damage control assistant) isresponsible for the training of shipboaidpersonnel in defense against NBC attack. He isalso responsible tor the Iprocurement,dis ibut ion, . maintenance of NBC defense

Chapter 2ENGINEERING DEPARTMENT

equipment. In addition, he must ensuredecontamination of personnel, equipment, andthe ship; and the management andtransportation of NBC casualties with the adviceand assistance of the medical officer.

FIRE MARSHAL

The litunarshal, under the engineer officerand the damage control assistant, is responsiblefor the maintenance and readiness of the ship'sfirefighting equipment. He is also responsible forthe prevention and elimination of fire hazards inthe ship.

GAS-FREE ENGINEER

The duties and responsibilities of the gas-freeengineer are given in chapter 9920 of Nav ShipsTeel:Weal Manual. Briefly, the gas-free engineertests and analyzes the air in compartments oritoids that have been closed and are beingopyned for inspection, to determine whethersuch, spaces are safe for personnel to enterwithout danger of poisoning or suffocating. Healso determines whether it is safe to perform"hot work" (welding or cutting) within, on theexterior boundaries, or in the way of such spaceswithout danger of fire or explosion. (The persondesignated as the gas-free engineer must have thequalifications set forth by NaySeaSysCom.

DIVISION , OFFICERS

In addition to the duties as set forth in U.S.Navy Regulations, the Sip's Organization andRegulations. Manual generally prescribes that adiVision officer shall:

I. Direct the operation of his divisionthrough leading petty officers, as prescribed inthe division organization.

2. Assign personnel towatches and dutieswithin the division (develop rotation programsfor battle stations, watches, and general dutieq,tolnesnia the training and proficiency ofassig a personnel).4

3. Ensure that division personnel receiveindoctrination, and military and professionaltraining.

.4. Prepare enlisted perforniance evaluation

sheets for personnel of his division.

5. Maintain a division notebook containingpersonnel data, cards, training data, a space andequipment responsibility log, the watch andbattle stations to be manned, and such otherdata as may be useful for the orientation of anofficer relieving him,and for ready reference.

6. Be responsible for all forms, reports, andcorrespondence originated or maintained Vi.'hisdivision..

7. Establish and maintain a divisionorganization manual and other directives whichmay be necessary for the administration of hisdivision.

8. Ensure that, presciibed secur4measuresjare strictly observed by personnOofitis divisien.

9. Mgice recommendations for personneltransfers ard changes in the division allowaneeto his department head.

10. Porward requests for leave, liberty, andspecial privilege and make recommendationsfor their disposition.

I. Conduct periodic inspections andexercises, and musters to evaluate theperformance and discipline of his division and toinitiate disciplinary action, when he deems itnecessary, in accordance with the Uniform Codeof Military Justice and other regulatory'directives.

TECHNICAL ASSISTANTS

The duties of technical assistants (1430,Warrant Officer, E-8, and .E-9 personnel) varywith the' different specialities. In. general, a,technical assistant's duties and responsibilitiesapply to the operation, maintenanee, andre,pairof machinery, equipment, and systems under thecoknizance of the division to which the teehnicalassistant is asiigned.

ENLISTED PERSONNEL

In addition to the general ratings for enlistedpersonnel of the engineering department, there .

are specific billets or assignments which require

FIREMAN

special Mention. Three of these billets are the oiland water king, the movie operator, and ,theboat engineer.

Oil and Water King

On a large ship, the billet for oil and waterking is usually divided into two billetsone forthe fuel. oil details, and the other for potable(fresh) water and feed water,

The oil and water king is a boiler Techniciahon steam-driven ships and is generally anEngine ma n on' diesel-driven ships. Hisresponsibilities.are as follows:

. 1, Supervising the operation of all valves ofthe fuel oil system, the transfer and boosterpumps, fuel oil manifolds, fuel oil heating coilsas necessary, and the fresh Water system asprescribed by the casualty control' bills for thoseSystems.

2. Properly maintaining fuel oil servicetanks, and shifting suction among service tanks.

3. flintaining the .distribution of fuel oiland wate so that the ship will remain on aneven keel and with proper trim.

4. Preparing fuel and water reports.

5. Testing anti recording the alkalinity,chloride content, hardness,'nnd other propertiesor -feed and boiler water, and making requiredtests of fuel oil.,Detailed information concerningsuch tests can be obtained from NavShipsTechnical Manual, chapter 9550 for oil tests andchapter 9560 for water tests.

6. 'Refer. to Basic Military Requirements,_NAVEDTRA 10054-D, for information onsafety precautions to be observed .vvh to handlingfuel oil,

Movie Operator

Movie operators are generally graduates of aSound motion picture school or duly qualifiedby competent authority. Provision is generallkmade to have a sufficient numb& of operatorsto accommodate the ship's needs, 16

''Boat *Engineer

Firemen, Enginemen, or Machinlit's Matesfrom the A division are detailed as boatengineers. Boat engineers °pc:rate, clean, ,iandinspect the parts of the boats Vssig d to them,Boat engine* repairs are under ken by

"'Enginomdn assigned to That duty, !

ENGINEERING DEPARTMENTRATINGS.

After serving as a Fireman for the requiredlength of4.thne, you may strike for a third classpetty officer's rating, But, first; Yop must makearrOportant decision;You may choose any of10' ocifferent ratings. The 'decision you make willdetermine largely the kind of work you will bedoing throughout 'the balance of your Navycareer. rk

In general, Rthe tt'engineering department .

ratings require ;:..art' aptitude' for thingsmebhanical, a degree of oficiency inmathematics and physics, and sme experiencein repair Work. A knowledge of mechanicaldrawing is also desirable, Rate Training Manualsand Nonresident Career Courses covering manyspects of basic - engineering are available.

Self-reliance, ingenuitk; and resourcefulness areparticularly important to any man striking ffiran engineeringrating. `'

Schools for engineering ratings are availableto those who 'can qualify. The various 'types ofschools are covered in Basic MilitaryRequirements, NAVEDTRA,.l 0054-D. A list ofall schools and their requirements is given in theCatalog of Navy Training Courses (CANTRAC),NAVEDTFtA. 10500.

The titles and job descriptions of the .various.engineering department ratings are given in thesections which follow.

MACHINIST'S MATE (MM)

MachinisITMates operate and maintain thepropulsibn turbines, reduction gears, condensers,air ejectors, and such miscellaneous 'auxiliaryequipment in the engineering spaces as pumps,air. compressors, generatots, evaporators, valves,oil purifiers, oil and water heaters, governors,-and propeller' shafts. Figure' shoWs a

Chapter 2ENGINEERING DEPARTMENT

Figure 2-2.Machinist's Mate recording evapdatorreadings. 139.1

Machinist's Mate recording readings from ane orator.

ENGI EMAN (EN)

Enginemen operate and maintain powerplants used to operate, shipboard auxiliaries andto propel boats and ships. In addition toworking with internal combustion engines(diesel and gasoline), Enginemen must knowhow to operate, maintain, and repair many kindsof shipboard auxliary equipment.

andequipment 'includes' refrigeration %and airConditioning systems, pumps, air ccompressors,and various kinds of hydraulic equipment.:Figure 2-43 shows an Engineman standing witch'on a diesel engine.

Figure 2-3.Engineman standing watch on a diesel engine.1

139.2

.11k

FIREMAN

.1

Figure 2-4. Machinery Repairman operating a milling machine.

MACHINERY REPAIRMAN (MR)

Machinery Repairmen make all types ofmachine shop repairs on shipboard machinery.,-This wOrk requires the skillful use of lathes,milling Machnes, boring mills, grinders, powerhacksaws, drill Oresses, and other machine tools,as well as 'all handtools' and Measuringinstruments uSlially found in a machine shop..The job of °restoring machinery to good workingorder, ranging)gsAt does from the fabriOation ofa simple pin rr3r.1i nk to the complete rebuildingof an intricate gear system, requires skill of the

f2

139.3

highesthighest order. Often, in the absence ofdimensional drawings or other designinkrmation, a Machinery Repairman mustdepend upon his ingenuity and know-how tosuccessfully machine a repair part. Figure 2-4shows a Machinery Repairman operating amilling machine.

BOILER 'TECHNICIAN (BT)

The Boiler Technicians operate all types ofmarine boilers and firefoom machinery (pumpsand forced draft blowers). They transfer, test,

Chapter 2 ENGINEERING .DEPARTMENT

L

Mid take soundings of fuel, and feed water tanks,They also maintain and repair boilers, pumps,and associated machiary. Figure 25 shows aBoiler Technician removing an atomizer from-aburner.

BOILERMAKER (BR)\.

Boilermakers test, maintain, and repaidmarine boilers, heat eXchangers, and associated.equipment; inspect boilers and effect correctivemeasures; perform electric arc and oxyacetylenewelding in boiler repairs; and maintain 'recordsand reports.

ELECTRICIAN'S MATE (EM)

Electrician's Mates stand watch, ongenerators, motors, switchboakds, and controlequipment; operate -searchlights and otherelectrical equipment; maintain and repair powerand lighting tqlrcuits, electrical fixtures, iiiotors,.ginerators, distribution .switehboards, and other

139.4 ekttcttical equipment; test for-founds or otherFigure Boiler Technician removing an atomizer casualties; and repair and, ild electrical

from a burner. %eqtiipment- in an electrical s Figure 20-ci'df.

v.

I

Figura 2-6.An Electrician's- ate taking readin s oriiiirain switchboard.

\13

FIREMAN

/7

139:6Figure 2-7.Hull Maintenance Technician preparing

to weld.

,1--

29.137DFigure 2-9.A Patternmaker, sawing a pattern.

%Apr

.74-T.442. """A

103.70Figure 2-8.Hull Maintenance technician removing

damaged pinks.

2014

Figurd2-10.A MAIder finishing a core.

r.

68.124

Chapter 2ENGINEERING DEPARTMENT

shows an Electrician's Mate taking readings atthe main switchboard.

INTERIOR COMMUNICATIONSELECTRICIAN (IC)

IC Electricians maintain and' repair interiorcommunications (IC) systems, gyrocompasssystems, amplified voice systems, and alarm andwarning systems, and related equipment; andstand IC and gyrocompass watches. (An ICElectrician may be responsible for maintainingmotion picture equipment aboard ship.)

HULL MAINTENANCETECHNICIAN (HT)

On 27 February 1970 the Secretary of theNavy approved the establishment of 'the HullMaintenance Technician (HT) general rating andthe attendant disestablishment of the Shipfittersgeneral rating (and included service ratings), andthe Damage Controlman general rating.

Hull Maintenance Technicians (HT) plan,supervise, and perform tasks necessary forfabrication, installation and repair of all types ofstructures shipboard and shore-based plumbingand piping systems, qualify in the techniques,skills and use of damage control and firefightingequipment, carpentry, nuclear; biological andchemical (NBC) defense; perform tasks in thefield of shipboard damage control NBC defenseand firefighting; organize, supervise and trainpersonnel in maintenance repair, NBC defenseand damage control duties. Figure 2-7 shows anHT prfparing to weld two pieces of angle iront ogether.

21

15

Hull Maintenance Technicians areresponsible for maintaining and preparingdamage control equipment and for preservingwatertight integrity, by such means as adjustingdogs and renewing gaskets on watertight doors,hatches, scuttles, etc. Figure 2.8 shows two Hj11IMaintenance Technicians removing damagedplanks.

PATTERNMAKER (PM)

Patternmakers make wooden, plaster, andmetal patterns, and other equipment used byMolders in a Navy foundry. They mountpatterns on match plates and on follow boardsfor production. molding. Pattern ers makemaster patterns; make' full scale 1 outs ofwooden patterns, core boxes, and tem fates; andindex and store patterns. Figure 2-9 illustrates aPatternmaker sawing a pattern.

MOLDER (ML)

Molders operate foundries aboard ship andat shore stations; make molds and cores, rigflasks, prepare heats, and pour castings .offerrous, nonferrous, and alloy metals; shake outand clean castings; and pour bearings. Figure2-10 illustrates a Molder finishing a core.

OTHER RATINGS

j In addition to the Group VII Engineeringand Hull Ratings, you will be required to knowsome of the other ratings in the Navy. Figure2-11 gives you a chart of the Navy Ratings.

FIREMAN

yr.

GROUT ICICX

* letGA EVA RD ^ U4 OT ST

BOATSWAIN'S MAT! QUARTERMASTER RADAR/AA. SIGNALMAN OCEAN SYSTEMS TECHNICIAN SONAR TECHNICIAN

GROUP IIORDE

) NrNANC FT TM NM yTGUNNER'S MAT! FIR! CONTROL TEHC/410AM TORPEDOsuur S MATIE MISSILE TECHNICIAN

EaRMICISTTECKNICIANDATA SYSTEMS TECIINICIAN

DSCLICTKONICS

GROUP

114TitAW4 CI:TICCZt

RAD VANRU

YEOMANTN

PERSONNPNELMAN POSTALFC

b. STOREKEEPER DISOURSING CLERK

GROUP

A 6>SK DR

PRECISION .

GROUP

ISMAINAEN

C VDATA PROCESSING

TECHNICIANJOURNALIST WES 1111.0IMPItAult SHIP'S SERVICEMAN COMMUNICATIONS TECHNICIAN

Mf let CT

ADICIOSTRATIVECOAutUNICATIONS YEIMIANAND CLERICAL

X X

GROUP VIIOSCELLANCOUS

GROUP VIIESIGRIEERING

ARO NULL

GROUP VIIICONSTRUCTION

GROUP IfAVIATION

GROUPMEDICIAL

GRISUP IO

CIENT/1 ,

LI DM MU

LITHOGRAPHER ILLUSTRATOR DRAFTSMAN MUSICIAN

HULL MAINTENANCETECHNICIAN

ICINTERIOR COVARINICATICNS

ELECTRICIAN

BUBUIL DER

giekMM EN MR EM

MACHINIST'S MATE ENOINEMAN MACHINERY REPAIRMAN I ELECTRICIAN'S MATE

GS

EC PI SE TRU A N

DA! TuRoINE!virtu tECHrocIAN

MLMOLDER

144

PAT TEMAAKIEROR

GORE IDAAKER

)181!A ED

ENGINEERING EQUIPMENTAID OPERATOR

CM

SR CONSTRUCTIONSTEELWORKER. MECHANIC

CE

UT CONSTRUCTIONUTILITIES MAN ELECTRICIAN

AVIATIONMACHINIST'S

MATE

-4 -044- .4134-11.4111rAO AT AQ AS

AVIATION AVIATION AV! TION .to AVIATIONDICHANCEMAN LECTRCNICS FIRE TROL ANtiSullmARINEMARFARE

CHNICIAN T NICIAN TECHNICIAN

AZ PRPRAVIATION M RCREW

MAINTENANCE SURVIVAL1-QuIPMENT441

AGAEROGRAPN ER'S

MATE

AW

AVIATIONANTISUBMARINE

WARFARE OPERATOR

AC AKAVIATION AVIATIONATK

AEAIR

CONTROLMAN STOREKEEPER ELECTRICIAN'SMATE

i.414001. .

PM

STRUCTURAL A/MECHANIC

AVIATION AVIATIO SUPPORT

TICHN ANEC1 ENT

AS

tRACITEDVMAN

AtNil 4111CIII

BOATSWAIN'SAVIAASTION PHOTOGRAPHE

MATE

R'S PHOTOGRAPHICMATE

PH

INTELLIGENCEAMN

eM%PT

}1" ...:HOSPITAL.HC

),

,,TEDcHiplicAiLAN ..-.t

22Figure2-11.Specialty arks for enlisted ratings.

16

0

3.10

-

CHAPTER 3

ENGINEERING F

s chapter is designed to acquaint youwith v. ous laws and phenomena of nature.Included is information pertaining to matter andenergy, force and motion, heat and temperature,pressure, combustion, the laws of perfect gases,and some fundamental information aboutMetals. The information provided here is generalin nature; but it has been included to give you abetter understanding of how or why engineeringmachinery operates or produces work. As youstudy this chapter, remember that anything thatoccupies space and has weight is calledMATTER.

PHYSICS

Tlie forces of physics and the laws of natureare at work in every single piece of machinery orequipment aboard ship. It is by these forces andlaws that the machinery and equipment producework.

MASS, WEIGHT, AND INERTIA

The physical principles of mass and inertiaare involved in the design and operation of theheat/ 'flywheels and bull gears that are at workin the ship's engineering plant. the great mass ofthe wheel tends to keep it rotating once it hasbeen set in motion. The high inertia of the wheelkeeps it from responding to small fluctuations inspeed and thus helps to keep the engine runningsmoothly.

The mass and the weight of an object are notthe same. The mass of an object is the quantityof matter which the object contains. The weightof the object is equal to the gravitational force

17

DAMENTALS

with which the object is attracted to the earth.Inertia is that physical property whichcausesobjects that are at rest to remain at rest, unlessthey are acted upon by some external force; andwhich causes objects moving at a constantvelocity to continue moving at this constantvelocity, and in the same direction, until actedupon by some external force.

FORCE

Force is what makes an object start to move,or speed up, or slow down; or keep movingagainst resistance. This foite may be either apush or a pull. You exert a force when yOu pdshagainst a truck, whether you movethe truck, oronly try to move it. You also exert a force whenyou pull on a heavy piano, whether you movethe piano, or only try to move it. Forcesproduce or prevent motion, or have a tendencyto do so.

A tendency . to prpvent motion is thefrictional resistance offered by an object. Thisfrictional resistance is called frictional force.While it can never cause an object to move, itcan check or stop motion. Frictional forceWastes power, creates heat, and causes wear.Although frictional force cannot be entirelyeliminated, it can be reduced with lubricants.

SPEED, VELOCITY,AND ACCELERATION

Speed is defined as the distance covered perun't of time. Velocity is speed in a certain,dir ction: Acceleration, is the rate at whichvel city changes. If, for example, the propellershaft rate of rotation increases from stop to 100

23

FIREMAN

revolutions1 per minute (rpm) in 20 minutes, theacceleration is 5 rpm. In other words, thevelocity has increased 5 revolutions per minute,during each minute, for a total period of 20minutes. A body with uniforth mdtion has noaccelerativ. When the velocity of an object'changes by the same amount each second orminute, you have uniform acceleration. Uniformdeceleration is obtained when the decrease invelocity is the same each second or minute.

ENERGY

Energy may be described as the ability to dowork. In the physical sense, work is doge when aforce acts on matter and moves it. We use heatenergy tq turn a steam turbine and electricenergy to drive motors. The mechanical energyof the pistons in an automobile engine istransmitted to the wheels. by the crankshaft,transmission, drive shaft, differential gears andrear 'axles. Nuclear energy is used to generateelectric power and to drive naval ships.

Perhaps the most common definition ofenergy is "the capacity for doing work."HoWever, this is not quite a complete statementbecause energy can produce other effects whichcould not be considered as work. For example,heat can flow from one object to anotherwithout`doing any work; yet heat is a form ofeliergy and the process of heat transfer producesan effect. Therefore, a 'better definition ofenergy is "the capacity for producing an effect.".

Energy is normally classified according tothe size and nature of the objects or particleswith which it is associated. "So we say thatmechanical energy is the energy associated withlarge objectsusually things that are big enoughto seesuch as pumps and turbines. Thermalenergy is energy associated with molecules.Chemical energy is energy that arises from theforces which bind the *atoms together in amolecule. Chemical energy is released whenevercombustion or any other chemical reaction takesplace. Electrical energy, light waves, and radiowaves are examples of energy that are associatedwith particles smaller than atoms. Nuclearenergy is obtained by splitting the atoms. Eachof these types of energy (mechanical, thermal,etc.) must also be classified as either (1) storedenergy, or (2) energy in transition. -2 4

18

Stored energy is energy that is actuallycontained within or stored within an object.There are two kinds of stored energy: potentialenergy and kinetic energy. Potential energy isenergy within an 'object waiting to be released;while kinetic energy is energy that has, beenreleased. For example, potential energy existswithin a rock resting on the edge of a cliff, waterbehind a dam, or steam behind a turbine throttlevalve.

Kinetic energy exists because of the relativevelocities of two ocmore objects. If you puslre*,,the rock, open the gate bf the dam, or open theturbine throttle valve, something will move. Therock will fall, the water will flow, and the steamwill jet through the turbine nozzle valves. Thusthe potential energy is converted to kineticenergy.

Energy in transistion exists when the rockhits the ground, the water hits the bottom of thedam of the paddles of a water wheel, or whenthe steam hits the blades of the turbine rotor.

In the examples just discussed, an externalsouce of energy was used to get things started.External energy was used to push the rock, toopen the gate of the dam, or to open thethrottle valve. Thus, you see that one energysystem affects another energy system. There is atremendous amount of chemical energy storedin fuel oil; but it will not raise the steam in theboiler until some external energy has beenexpended to start the oil burning.

Energytati be measured. The most commonmeasurement of expended energy is in workunits of foot-pounds. When an object has beenmoved through a resisting force. work has beendone.

WORK

The turbines and other Power e pmentused aboard ship are important because they dowork. Work is defined as the result of forceToying through distance. The unit of ineasurefor work is the FOOT-POUND (ft -lb). The twoparts of this unit are the, POUND OF _FORCEand the FOOT OF DISTANCE.

Force is measured in pounds. Thegravitational pull on an object weighing I pound

Chapter 3ENGINEERING FUNDAMENTALS

is a force. of 1 pound. If you lift a 1-poundweight from ground level to a height of 1 foot,you exert a force of 1 pound thrOugh a distanceof 1 foot, and you have done 1 foot-pound ofwork in the process...A force of 100 pounds isrequired to raise a 100-pound anvil; if you lift itto the top of a 30-inch bench, the work youhave done is 2 1/2 ft x 100111= 250 ft-lb. Work(in foot-pounds), thdrefore, equals the. force (inpounds) times the distance (in feet).

Now, suppose you want to move a 60-poundanvil across the deck without lifting it, It willtake a considerable force to slide, the anvil. Ifyou slide it 10 feet, you do 600 foot-pounds ofwork. Here the force of 60 pounds is required toovercome the resistingforce of friction betweenthe anvil and the deck. A great deal of the workdone by any machine is the Overcoming of manyfrictional forces which resist the motion of theparts.

POWER

The, ship's main engines, boilers, mainreduction gear, main shaft, and propellers arefrequently called the POWER PLANT; and theyare commonly rated according to how muchpower they can develop. For example, it mighttake one man 10 hours to load 20,000 poundsof ammunition on a truck, whereas a cranecould do the. same job in 5 minutes. The amountof work done is the same, but the crane is muchmore powerful than the man. It can do the workfaster. Power, then relates to work and time; it isthe time rate. of doing work. If we assume thatthe ammunition is raised an average height' of 6.feet, the work done is equal to 6 ft x 20,000 lbor 120,000 ft-lb. Considering the man also as amachin6, the power of each of the two machinesif found by dividing this amount of work by thetime required in each case. Expressing 10 hoursin minutes, the man would work at the rate of120,000 ft-lb- + 600 mil]. = 200 ft-lb per min.The computed power of the crane would be120,000 ft-lb ÷ 5 min..; 24,000 ft-lb per miner400 ft-lb per sec.

The most common unit of power is knownas the HORSEPOWER. One horsepower isequivalent to 550 ft-lb per second, or 33,000ft-lb per ,minute. Thus, if a lifting machine miles

19

a weight of 100 pounds at the rate of 250 ft-lb-per/second, the machine is exerting only 0.454,horsepower (250 ft-lb 4. 550 ft-lb = 0.454 ltp).

If crane hoists 2,000 pounpls of ,cargo toheight of 30 feet in 5 seconds, how muchhorsepower is developed? Here is how to get theanswer:

Power = work 2,000 lb X30 fttime 5 sec

= 12t000rft-1b per sec

12000 ft-lb per secHorsepower 21.8550 ft-lb per sec

Or suppose a turbine has .a knownhorsepower of 37,500 at rated capacity, and youwant to know hovt; much work it does. You findout by multiplying the developed horsepower by -the hours in operation. This givesHORSEPOVVER-HOURS, which is a measure ofwork for main propulsion machinery,

LAWS OF GASES

The energy transformation of major interestin the shipboard engineering plant is thetransformation from heat to work. To see howthis transformation occurs, we need to considerthe pressure, temperature, anll volumerelationships which hold ture for gases. In themiddle of the 17th century, Robert Boyle, anEnglish scientist, made some interestingdiscoveries concerning the relationship betweenthe pressure, the temperature, antithe volume ofgasps. In 1787, ,facqties Charles, a. Frenchman,proved that all gases ioxpand the same amountwhen heated one degred. if the pressure is keptconstant. The 'relationships that these two mendiscovered are summarized as follows:

1. tWhen the temperature is held constant).an increase in the pressure on a gas causes-proportional decrease in volume, A decrease inthe prewiire causes a proportional increase involume.

2. When the pressure is held constant, anincrease in the temperature 'of a gas, causes\a

RENIAN

prdtortional increase in volume. A decrease in,the 'temperature, causes a proportional decreasein volumik, '-'1

' 3. When the volume is held constant, anincrease in the ,temperature of a gas causesproportional incre.aselin pressure. A -decrease nthe temperature causes a proportional decrein pressure.

e

Suppose we have a boiler in which steam hasjust begun to form. With the steam stop valvesstill closed, the Irolume of the steam remainsconstant while the pressure and the temperatureare both increasing. When operating pressure isreached and the steam stop valves are op-ined,the high pressure of the steam causes the steamto flow to the turbines. The pressure `61steam thus provides the Rprential for dowork; the. actual conversion of heat to wodone in the turbines.

O

PRESSURE AND VACUUM

IS

Because pressure is very' imRortant to the"engineering plant, necessiry that youunderstand the rela*nships between gagepressure, atmospheric pressure, vacuum, andabsolute pressure. These ' relationships areindicated in figure 3-1.

A 11.1.).WHMG HRE5St1RE-

14.7 PSI ABSOLUTE, OR30 INCHES OF MERCURY ABSOLUTE.

OR ZERO GAGE PRESSURE,OR ZERO VACUUM

30 INCHESOF MERCURY

0

Gage Presiuri

Gage pressure IS the pressure actually shownon the dial of a gage w14ich registers pressures ator above_ atmospheric pressure, Gage pr, ssure is >.actually shown in 'pounds Ilbr scittare inc (psi);

,1 but it may be shown jn ,inches Pof water,mercury, or other lig*, A reading of 1 inch oft-water means that the exerted preiltire is able tosupport a _column of,w1ter l'inclk high, or that. a

,column -*water in a Ultube will be displacedinch by the pressure being mdasured. Similarly, agage pressure reading of 12 inches of mercurymeans that the measured pressUre is atqe tosupport a column of mercury 12 inches bth.Gages are calibrated in inches of water whenthey are to be used for measuring very low..pressures. Inches of mercury may be used whenthe range of pressures to be measured isso ewhat higher, since mercury isapproximately 14 times heavier than water.

Note that a gage pressure reading of zeromeans that the pressure being measured isexactly the same as the existing atmosphericpressure. A gage reading of 50 psi means that thepressure being measured is 50 psi IN EXCESSOF the existing atmos erie ptesss0 ure.

7

Atmospheric Pressure

AhriOspheric pressure,' or the pressu eexerted iby the weight of the air tatmosphere, is. Measured with a EAROMETE(fig. 3-2), A bar9meter is sirriilar td a manornete

45- . s (see chapter 9), excetit that the indicating tube.

is sealed at the top, A:barometer may be madeby filling a tube' with mercury And then invertingit 'so at the open, end rests in "a container oftiler which is open to 'the atmosphere.absense ofpressure at the closed end of tie tubepermits atmospheric pressure, acting upon thesurface of the mercury in the oDen container, to,hold the mercury in the tube at a height whichcorregponds to the pressure being exerted.

Normally, at sea level atmospheric...pressurewill hold the colunln df mercury at a ,hefght ofapproximitOpyy 30ches. Since a ,column ofmercury 1 itibh high exerts a pressure -of 0.49pounds per square inch a 30-inch column of

O ,

PSI OR INCHES OF MERCURY'.

1318Figure 3,tRelaticinships between vacuum, gage

pressure, absolute'pressure, and atmospheric pressurkI

I\t,

el Chapter 3ENGINEERING FUNDAMENTALS

HEIGHT OFMERCURYCOLUMN ISREAD HERE

t.

ATMOSPHERICPRESSUREFORCES COLUMNOF MERCURYUP INTO TUBE

32

31

30

29

28

69.86figure 3-2.Operating prinCiple of mercurial barometer.

mercury exerts a pressure which is equal to (30.x 0.49) 14.7 pounds per square inch. Thus, wecan say that atmospheric pressure (zero gagepressurg) at sea level is 14.7 psi, or 14.7 poundsper square inch absolute(psia) Notice, however,that 14.7 psi is the STANDARkfor atmosphericpressure. Since fluctuations from this standardare shown on the barometer, the termBAROMETRIC PRESSURE is used to describethe atmoshperic pressure which exists at anygiven moment. As a rule, you can use the termATMOSPHERIC PRESSURE and the value 14.7.psi in place of the actual barometric pressure;but there may be times when it will beimportant to know the actual (barometric)

pressure; in order1to make prigise measurementsof gage pressure or vacuum.

Vacuum

A spac-e in which. the pressure is less thanatmospheric pressures said to be under vacuum.The amount of vact Wn is expressed in terms ofthe difference between the pressure in the spaceand the existing "atmospheric pressure. Vacuumis measured i inches of mercurythat is, t11r.,number of . inchq a column of mercury in a

tube will be displaced by a pressure equal tothe .difference between the pressure in thev cuum space and the.,, existing atmospheric

ressure.

Vacuum gage scales are marked from 0 to30. When a vacuum gage.reads,zero, the pressurein the space is the same as the existingatmospheric jireatirecor, in other words, thereis no vAtutTh. A vacuum gage reading of 30inches of mercury indicates a nearly perfectvacuum. In actual practice, it is impossible toobtain a perfect vacuum; and the highestvacuum gage readings are seldom over 29 inchesof mercury.

Absolute Pressure

Absolute pressure is atmospheric pressureplus gage pressure, or atmospheric pressureminus vacuum. For example, if gage pressure is300 psi, absolute pressure is 314.7 psi; or if themeasured vacuum is 10 inches of mercury,absolute pressure is approximately \ 20 inches ofmercury. It is important to note ..that\ theamount of pressure in a space under vacuum canbe expressed only in terms of absolute pressure.

Sometimes it is necessary to convert areading from inches of mercury to pounds persquare inch. figure 3-1 gives you all theinformation you need to make this conversion.Since atmospheric pressure is equal to 14.7 psiof to 30 inches of mercury, it is easy to see that

inch of mercury is equal to (14.7 psi i- 30)0.49. Now convert your gage reading to absolutepressure (in inches of mercury) s and thenmultiply this figure by 0.49 psi. FOr ex mple to

21

27 1?,

FIREMAN

convert a vacuum gage reading of 14 inches, ofmercury to psi, you _would proceed as follops:

1. Convert 14 inches of mercury vacuum toabsolute pressure. Absolute pressure isatmospheric pressure minus vacuum (30 inches -14 inches = 16 inches).

2. Multiply the absolute ,pressure in inchesof mercury by 0.49. Since 1 irith of mercury isequal to 0.49 psi, 16 inches of mercury is equalto 16 x 0.49 psi) 7.8 psi (approximately 8 psi).

ember that this answer is in terms oflute pressure.

fir

As you can see, it is also easy to convert psito inches of mercury. Since atmosphericpressure is equal to 14.7 psi or to 30 inches ofmercury, 1 psi is equal to (30 inches of mercury÷ 14.7) 2.04 inches of mercury. For example, 10psi absolute is equal to (10 x 2.04 inches ofmercury) 20.4 inches of mercury absolute.

In order to interpret the reading, on apressure gage, you must know the location ofthe gage in relation to the line in which thepressure is being measured. As a general rule,pressure gage connections are led from the topof the pressure line. Ckcasionally, however, it isnecessary to locate a pressure gage at somedistance below the pipe; then the reading on thegage will indicate the pressure being measuredplus thpressure exerted by the.weight of thecolumn of liquid above the gage. The requiredcorrection should be made in calibration of thegage. If the correction has not been made incalibration, it must be made in theinterpretation of the gage reading.

Correction fO'r a head of liquid should bemade as follows:

1. Measure the vertical distance from thecenter of the gage to the line in which thepressure is being, measured.

2. For each foot of the distance measured,subtract from themgage reading the weight of acolumn of liquid l'foot high and ;,.1 inch squarein cross section. If you are measuring pressureon a steemfor-wffter line, you must correct for apressure head of water. Since a column of water1 foot high and 1 inch square in cross section

22

28

weighs 0.433, pounds, you subtract 0.433 psifrom the gage reading for each fobt of drop.(CAUTION: The weight of each liquid isdifferent, id must be determined before youcan make is correction.)

For example, to correct a pressure gagereading for a pressure head of water, assume thata steam pressure gage is connected 10 feet belowthe steam line. The steam cools and condenses inthe gage connection line, filling the connectionline with water. The uncorrected gage reading is250 psi. Multiply, 0.433 psi by 10, and thensubtract the resulting figure from 250 psi:

( 1 ) 0.433 psi x 10 = 4.33 psi.(2) 250 psi - 4.33 psi = 245.67 psi.

Thus the true pressure in the steam line is245.67; or approximately 246 psi.

It is sometimes necessary to connect a waterpressure gage at some distance above the pointat which the pressure is being measured; thenthe_reading on the gage will show the pressurebeing measured minus the pressure required tosupport We column of water up to the gage. Tocorrect the reading you must add the weight ofthe column of waterthat is, yotr must add0.433 psi to the gage reading for eabh foot ofrise. a

For example, assume that a water pressuregage is connected 5 feet above the point atwhich the pressure is being measured. The gagereading is 30 psi. To obtain the actual pressureat the point of measurement, you must add (5 x0.433 psi) 2.17 psi to the gage reading. Thus theactual pressure is 32.17 psi.

PRINCIPLES OF HYDRAULICS

The word hydraulics is derived from theGreek word for water (hyd6r) plus the Greekword for a reed instrument like an oboe (autos).The term "hydraulics" originally covered thestudy of the physical behavior of water at restand in motion. However, the meaning ofhydraulics has been broadened to covet thephysical behavior of all liquids, including the oilsthat are used in present day hydraulic systems.

(;#

Chapter 3ENGINEERING FUNDAMENTALS

/

FORCE 1 e 100 LBS. FORCE 2 = 100 LBS.

Figura 3-3.Principlo of mochapicol hydraulics.

During the period before World War I, theNavy began to apply hydraulics extensively tonaval mechanisms. Since that time, navalapplications have increased to the extent thatmany ingenious hydraulic devices are used in thesolution of problems of gunnery, navigation, andaeronautics. Aboard s ip today the applicationsof hydraulics include a chor windlasses, powercranes, steering gear, r mote controls, powerdrives for the elevation guns and training ofmounts and turrets, po der and projectilehoists, recoil systems, gun rammers, and airplanecatapults.

The foundation for modern hydraulics beganin 1653 when Pascal discovered that "pressureset up in a liquid acts equally in all directions."This pressure acts at eight angles to thecontaining surfaces.

When we apply a force to the end of acolumn of confined liquid, the force istransmitted not only straight through to theother end, but also equally in every directionthroughout the columnforward, backward, andsidewaysso that the containing vessel isliterally filled with pressure. This is the reasonthat a flat firehose takes on a circular crosssection when it iS filled with water underpressure. The outward push of the water is equal

23

29

5.181

in every direction. Water will leave the hose atthe same velocity, through leaks, regardless ofwhere the leaks are in the hose.

Let us now consider the effect of Pascal'slaw in 'the system shown in figure 3-3. If theforce at piston A is 100 pourids and the area ofthe piston is 10 square inches, then the pressurein the liquid must be 10 pounds per square inch(psi). This pressure is transmitted to piston Bsothat for every square inch of its area, piston Bwill be pushed upward with a force of 10pounds:- In this example we are merelyconsidering a liquid column of equal crosssection so that the areas of the pistons\are equal.All we have done is to carry a 100-pound forcearound a bend; however, the principle illustratedis the basis for practically all mechanicalhydraulics.

The same principle may be applied wherethe input piston is much smaller than the outputpigton or vice versa. Assume that the area of theinput piston is 2 square inches and the area ofthe output piston is 20 square inches. If youapply a pressure of 20 pounds to the smallerpiston, the pressure created in the liquid willagain be I0 pounds per square inch because theforce is concentrated on a smaller area. Theupwatd force on the larger piston will be 200

FIREMAN

pounds 10 po ds for each of its 20 squareinches. Thus yo can see that iftwo pistons areused in a hydraulic system, the Torce acting oneach piston will be directly prOportional to itsarea, and the magnitude of each force will be theproduct of the pressure and the area of thepiston.

PRINCIPLES OF PNEUMATICS

Pneumatics is that branch of Mechanics thatdeals with the mechanical properties of gases.Perhaps the most common application of theseproperties, used in the Navy today, is the use ofcompressed air. Compressed air is used totransmit pressure, according to Pascal'sprinciple, in a variety of applications. Forexample, in tires and air-cushioned springs,compressed air acts as" a .cushion to absorbshock. Air brakes on locomotives an largetrucks contribute greatly to the safety ofrailroad and truck transportation. In the Navy,compressed air is used in numerous ways. Forexample, tools such as riveting hammers andpneumatic drills are air ozerated. Automaticcombustion control systemslitilize compressed

pi air for the operation of the instruments.Compressed air is also used in diving bells anddiving suits. Perhaps a brief discussion on the useof compressed air as an aid in the control ofsubmarines will best explain the theory ofpneumatics.

Submarines are designed with a number oftanks that may be used for the control of theship. These tanks are flooded with water tosubmerge; or they are filled with compressed airto surface.

The compressed air for the pneumaticsystem is maintained in storage tanks (calledbanks) at a pressure. of 4,500 psi. Duringsurfacing the pneumatic system deliverscompreSsed air to the desired control tanks.Since the pressure of the air is greater than thepressure of the water, the Water is forced out ofthe tank. As a result, the weight of the shipdecreases; it becomes more buoyant, and thustends to rise to the surface.

HEAT

You undoubtedly know from experiencethat heat and temperatifit are related; however,

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30

they are no the same. Water from a water mainfeels cool until it has been over a fire a fewminutes. It evidently must have receivedsomething (from the fire. If you place twopennies together, one of which was heated bybeing held in the flame of a match, in a shorttime the tWo pennies will be equally warm.Again, something passed into the cooler objectand made it hot. That something is called heat.

Many forms of mechanical action also'produce considerable quantities of heat. Forexample, you rub your hands together to warmthem when they are cold. Matches are ignited byrubbing them on a rough surface. A HullMaintenance Technician can notice heat in apiece of metal after hammering it; and the headof a nail is heated when the nail is driven intowood.

The molecules in the nail (as in all matter)are in continual motion. The blow on the nailincreases the molecular motion. late moleculesin the top layer receive the impulse from thehammer and vibrate with greater violence. Theincreased vibration and energy of motion ispassed on\ to layer after layer of molecules.Thus, the effect produced by the blow is ageneral increase in the motion of the molecules.This energy of molecular motion is called heat.

Because molecules are constantly in motion,they exert a pressure on the walls of the pipe,boiler, cylinder, or other object in which theyare contained. Also, the temperature of anysubstance arises from and is directlyproportional to the activity of the\ molecules.Therefore, every time you read theh'nometersand pressure gages you are finding outsomething about the amount of internal energycontained in the substance. !High pressures andtemperatures indicate that the molecules aremoving rapidly and that the substance thereforehas,a lot of internal energy.

Heat is a more familiar term that internalenergy!, yet one that may actually be moredifficult to define correctly. The importantthing to remember is that HEAT IS THERMALENERGY IN TRANSITIONthat is, it is

theimal energy that is moving from onesubstance orsystem to another.

Chapter 3ENGINEERING FUNDAMENTALS

An example will help to b illustrate thedifference between heat and internal energy.Suppose there are two equal lengths of pipe,made of identical materials and containing steamat the same pressure and temperature. One pipeiS well insulated, the other is not insulated at all.From everyday experience you know that moreheat will flow from the uninsulated pipe tharifrom the insulated pipe. When the two pipes arefirst filled with steam, the steam in one pipecontains exactly as much internal energy as thesteam in the- other pipe. We know this is truebecause the two pipes contain equal volumes ofsteam at the same pressure and at the sametemperature. After a few minutes, the steam inthe uninsulated pipe will contain much lessinternal energy than the steam in the insulatedipe, as we can tell by measuring the pressurend the temperature of the steam in each pipe.hat has happened? Stored thermal

energyinternal energyha Toyed from oneplace to another, first from the steam to thepipe, then from the uninsulated pipe to the air.The MOVEMENT or FLOW of thermal energy iswhat should be called heat.

Units of Measurement

Both internal energy and heat are" usuallymeasured using the unit called the B ITISHTHERMAL UNIT. (Btu). For most p cticif?engineering purposes, I Btu is defined as theamount of,-thermal energy required to raise thetemperature of I pound of water 1 °F.

When large amounts of thermal energy areinvolved, it is usually more convenient to usemultiples of the Btu. For example.. 1 kBtu isequal to '1,000 Btu, and' I mint], is eqifial to1,000,000 Btu.

Another unit in which thermal energy maye measured is the CALORIE, the amount ofeat required to raise the temperature of 1 gram

of water 1° C. One Btu equals 252 calories.

Sensible Heat and Latent Heat

Sensible heat and latent heat are terms oftenused to indicate the effect that the flow of heathas on a substance. The flow of heat from one

substance to another is normally reflected in atemperature change in each substancethehotter substance becomes cooler, the coolersubstance bedomes hotter. However, the flow ofheat is not reflected in a temperature change In asubstance which is in the process of chatigink.,.from one physical state (solid, liquid, or gas) toanother. When the flow of heat is reflected in atemperature change, we say that SENSIBLEHEAT has been added to or removed from the-substance. When the flow of heat is not reflectedin a temperature change bnt is reflected in thechanging physical state of a substance, we saythat LATENT HEAT has been added orremoved.

Does anything bother you in this lastparagraph? It should. Here we are talking aboutsensible heat and Tatcn$ heat as though we hadtwo different kinds of heat to consider. Asnoted before, this is common (if inaccurate)engineering language. So keep the followingpoints clearly in mind: (1) `heat is the flow Ofthirmal energy; (2) when we talk about addingand removing -heat, we mean that we areproviding temperature differentials so thatthermal energy can flow f ?om one substance toanother; and (3) when we talk about sensibleheat and latent heat, we are talking about twodifferent kinds of EFFECTS that can beproduced by heat, but not about two differentkinds of heat.

The three basic physical states of all matterare SOLID, LIQUID, and GAS (or vapor). The'physical state of a substance is closely related tothe distance between molecules. As a generalrule, the molecules are closest together in solids,farther apart in liquids, and farthest apart ingases. When the flow of heat to a- substance isnot reflected in a temperature change, we knowthat the energy is being used to increase thedistance between the molecules of the substanceand thus to change it from a solid to a liquid orfrom liquid to a gas. You might say that latentheat is the energy price that must be paid for achange of state from solid to liquid or fromliquid to gas. The energy is not lost; rather, it isstored in the substance as internal energy. Theenergy price is repaid, so to speak, when thesubstance changes back from' gas .to liquid orfrom liquid to solid, since heat flows from thesubstance during these changes of state.

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FIREMAN

SENSIBLE\ HEAT

300°

212°200°

100°

32°

016

LATENTHEAT,OF SENSIBLEFUSION HEAT

LATENT HEATOF VAPORIZATIAN

(OR LATENT HEAT SENSIBLE

OF CONDENSATION) HEAT

ICEWARMING

ICE

I MELTING

SUPERHEATINGy

/1\WATERBOILING

doo--STEAM

CONDENSINGSTEAM

COOLING '

ICEWATER COOLING

FREEZING

144. 180, 7 970

BTU PER POUND OF WATER

44

Figure 3.4. Relationship between sensible heat and Talent heat for water at atmoshperic pressure.

Figure 3-4 shows the relationship betweensensible heat and latent heat for one surance,water, at atmospheric pressure. (ThV'same kindof chart could be drawn for other substances;however, different amounts of thermal energywould be involved in the changes of state.)

If we start with 1 pound of ice at 0° F, wemust add 16 Btu to rasie the temperature of theice to 32° F. We call this adding sensible heat.To change the pound of ice at 32° F to a poundof water at 32° F, we must add 144 Btu (theLATENT HEAT OF FUSION). There will be no

38.1

change in temperature while the ice ,is melting.After all the ice has melted, however, thetemperature of the water will be raised asadditional heat is supplied. If we add 180Btu ti. at is, 1 Btu fot each degree oftemperature between 32° F and 212° Fthetemperature of the water will be raised to theboiling point. To change the pound of 'water at242° F t9 a pound of steam at 212° p, we mustadd 970 Btu (the LATENT HEAT OFVAPORIZATION). After all the water has beenconverted to steam the addition of more heat

32 ,26

Chapter 3 ENGINEERING FUNDAMENTALS

will cause an increase in the temperattrre of the''steam.41f we add about 44 Btu to the pound ofsteam which is at 212° F, we can superheat it to300° F.

The same, relationships apply when heat isbeing removed,: The removal of44 Btu from thepound of steam which is at 300° F will cause thetemperature to drop to 212° F. As the pound ofsteam at 212° F changesto a pound of water at212° F, 970 ctu are given? off. When a substanceis changing iThm a gas or vapor to, a liquid, weusually use the term LATENT HEAT OFCONDENSATION for the heat thatis given off.Notice, however, that the latent heat ofcondensation is exactly the same as the latentheat of vaporization. The removal of another180 u of sensible heat will lower thetemperature of the pcumd of water from 212° Fto 32° F. As the pound of water at 32° Fchanges to a Pound of ice at 32° F, 144 Btu aregiven off without any accompanying change intemperature. Further removal of heat causes thetemperature of the ice to decrease.

TEMPERATURE '

The temperature of an object is a measure ofhow hot or cold the object is; it can be measuredby thermometers and read on their temperaturescales..

The temperature scales employed to measure" temperature are the Fahrenheit Kali: and the

Celsius (centigrade) scale. In engine..ring and forpractically all purposes - in the Navy, theFahrenheit scale is used. It may, however, benecessary for you to convert Celsius readings tothe Fahrenheit scale, so both scales areexplained here.

The FAHRENHEIT SCALE has two mainreference pointsthe boiling point of pure waterat 212°, and the freezing point of pure water at32°. The size of a degree of Fahrenheit is 1/180of the total temierature change from 32 to212°. And the scale can be extended in eitherdirectionto higher temperatures without anylimits, and to lower temperatures (by usingMINUS degrees) down 'to the lowesttemperature theoretically possible, the absolutezero. This temperature is -460°, (31'492° belowthe freezing point of water.

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33

In the CELSIUS SCALE, the freezing pointof 'pure water is 0° and the boiling point of purewater is 100°. Therefore, 0° C and 100° C areequivalent to 32° F and 212° F, respectively.Each degree of Celsius is larger than a degree ofFahrenheit since there are only 100° Celsiusbetween the freezing and boiling p9ints ofwater, while this same temperature changerequires 180° on the Fahrenheit scale. Therefore

the degree of Celsius is 100 or or 1.8° Fahrenheit.

In the Celsius scale absolute zero is -273°.Figure 3:5 shows the two temperature scales

in comparison and also introduces the simplest

FAHRENHEIT SCALEFAHRENHEITTEMPERATURES

' 270260250240230220210

200190

170

160150140130

120110

100

00BO

70605040302010

0-10-20-30-40

A111111111111

1111111111

CELSIUS SCALECELSIUS

TEMPERATURES

tu)"c

MATER BOILS OR CONOENSE S

194--

J94

32.....4CE MELTS -WATER FREEZES

.214.

,A

MERCURY

120

110

100 _

90

BO

70

60'

50

40

30

20

I00

10

-20

-30

-40

MELTING ICE

BOILING WATER -

Figure 3-5.Temperature scales.3311

FIREMAN .

^

of the temperature measuring instruments, theliquid-in-glass thermometer.' The twothermometers shown are exactly alike in sizeap* shape; tl-tb only difference is the outsidemaitings,,,,or scales on them. Each thermometeris a hollow glass tube which has a mercury-filled'bulb at the bottom, and which is sialed at thetop. Mercury, like any liquid, expands whenheated and will rise in the hollow tube. Theillustration shows the Fahrenheit thermometerwith its bulb standing in ice water (32° F), whilethe 'Celsius thermometer is in boiling water( 1 00° C).

The essential point to remember is that thelevel of the mercury in a thermometer dependsonly on the temperature to which the bulb isexposed. If you were to exchange thethermometers, the mercury in the Celsius.thermometer would drop to the level at whichthe mercury now stands in the Fahrenheitthermometer, while the mercury ' in theFghrenheit thermometer would rise to the levelaf which tilt mercury now stands in the Celsiusthermometer. The temperatures would be 0° Cfor the ice water and. 212° F for the boilingwater.

If you place both thermometers in watercontaining lumps of ice, the Fahrenheitthermometer will read 32° and the Celsiusthermometer will read 0°. Heat the waterslowly. The temperature will not change untilthe ice in the water has completely melted (agreat deal of heat is required just to melt theice), then both mercury columns will begin Co

rise. When the mercury level is at the +10° markon the Celsius thermometer, it will be at the+50° mark on the Fahrenheit thermometer. Thetwo columns will rise together at the same speedand, when the water finally boils, they will standat 100° C and 212° F, respectively. The sametemperature changethat is, the same amount ofheat transferred to the waterhas raised thetemperature 100° Celsius and 180° Fahrenheit,but the actual change in heat energy is exactlythe same.

COMBUSTION

The term "combustion" refers to the rapid.10.mical union of oxygen with a fuel. Theperfect cbmbustion of fuel should result in

carbon dioxide, nitrogen, water vapor, andsulphur 'dioxide. The oxygen required to burnthe- fuel is obtained from the air. Air is amechanical mixture containing by weight 21percent oxygen, 78 percent "nitrogen, and I

percent other gases. Only oxygen is used incombustion of the fuel;nitrogefi is an inert gaswhich has no chemical effect upon the.cotnbustion.

The chemical combination obtained duringcombustion results in the libeption of heatenergy, a portion of which is, used to propel theship. Actually, what happens is a rearrangementof the atoms of the chemical elements into newcombinations of molecules. In other words, asthe Semperature of the fuet, oil in the presence ofoxygen is increased to the ignition point, the.'various chemical elements in the fuel begin toseparate from each other and to unite withcertain amounts of oxygen to form entirely.iiew.substances, which give off heat energy in theprocess. A mod fuel has a high' speed ofcombustion, thus producing a large amount ofheat in a short time.

PERFECT COMBUSTION is the objective.However, this cannot be achieved as yet in eithera boiler -or the cylinders of aninternal-combustion engine. Theoretically, it is

simple. It consists of bringing each particle ofthe fuel (heated to its ignition temperature) into

.contact with the correct amount of oxyvn. Thefollowing factors arc involved:

I . Sufficient air must be supplied.

2., The air and flIel particles must bethoroughly mixed.

3. Temperatures must be high enough tomaintain combustion.

4. Enough time must be allowed to permitcompletion of the process.

However, COMPLETE COMBUSTION canbe achieved. This is accomplished by supplying,more oxygen to the process than -would berequired if perfect combustion were possible.The result is that some of the excess oxygenappears in the combustion gases.

28.

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t.-

C)

!)Chapter 3ENGINEERING FUNDAMENTALS

STEAM

Stearn is water to which enough heat hasbeen added to convert it from the liquid to thegaseous state. When heat is added to water in anopen container, steam forms, but it quicklymixes with air and cools back to water which isdispersed in the air, making the air more humid.If you add the heat to water in a closedcontainer, the steam builds up pressure. If youadd exactly enough heat to convert all the waterto steam at the temperature of boiling water,you get saturated steam. SATURATED STEAMis steam saturated with all the heat it can hold atthe boiling temperature of water.

The boiling temperature of water becomeshigher aslhe pressure over the water becomeshigher, 'Steam hotter than the boilingtemperature of water is called SUPERHEATEDSTEAM. When "steam has 250° of superheat,the actual. temperature is the boilingtemperature plus 250° F. At 600 psi the boilingtemperature of water is 489° F. So if steam at600 psi has 250° F of superheat, its actualtemperature is 739° F. WET STEAM is steam atthe boiling temperature which still containssome water particles-. DESUPERHEATEDSTEAM is steam which has been cooled by beingpassed- through a pipe extending through thesteam drum; in the process the steam loses allbut approximately 20°F or 30°F of itssuperheat. The advantage of desuperheatedsteam is that it is certain to be dry, yet not sohot as to require special alloy steels for theconstruction of the piping that carries thedesuperheated steam about the ship.

METALS

As you look around, you see that not only isyour ship constructed of metal, but also that theboilers, piping system, machinery, and even yourbunk and locker are constructed of some type ofmetal. No one type of metal can serve all theneeds abbard -ship. Many types of metals ormetal alloys must be used. A strong metal mustbe used for some parts of a ship, while alightweight metal ais needed for other parts.Some areas require spedial metal that can beshaped or workeslyeg easily.

The physical properties. qa some metals ormetal alloys make them more. suitable for oneuse than for another. Various terms are used indescribing the physcial properties of metals. Bystudying the following . explanations of theseterms you should have a better understanding ofwhy certain metals are used on one part of theship's structure and not on another part.

STRENGTH refers to the ability of a metalto maintain heavy loads (or force) withoutbreaking. Steel, for example, is strong, but leadis weak.

HARDN SS refers to the ability of a metalto resist pene ation, wear, or cutting action;

. MALLEABILITY is a property of a metalthat allows it to be rolled, forged, hammered, orshaped, without cracking or breaking. Copper isa very malleable metal.

BRITTLENESS is a property of a metal thatwill alldw it to shatter easily. Metals such as castiron or cast aluminum, and some very hard steelsare brittle.

DUCTILITY refers to the ability of a metal ,"to stretch or bend without breaking. Soft iron,soft steel, and copper are ductile metals.

TOUGHNESS Is the property of a metal thatwill not permit it to tear or shear (cut) easilyand that allows it to stretch without breaking.

Metal preservation aboard ship is acontinuous operation since the metals areconstantly exposed to fumes, water, acids, andmoist salt air; all of these will eventually causecorrosion. The corrosion of iron and steel iscalled rusting and results in the formation ofiron oxide (iron and oxygen) on the surface ofthe metal. Iron oxide (or rust) can be identifiedeasily by its reddish color. (A blackish hueoccurs in the first stage of rusting but is seldomthought of as rust.) Corrosion can be reduced .orprevented by using better grades of base metals:by adding special metals such as nickel andchromium, or by coating the surface with paintor other metal preservatives.

Metal and alloys are divided into two generalclasses: ferrous and nonferrous. Ferrous metalsare those that -are composed primarily of iron.Nonferrous metals are those that are composed

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FIREMAN

p arily of some element or elements otherth iron. One way to tell a common fen;ousmetal from a nonferrous metal, is by using amagnet; most ferrous metal is magnetic andnonferrous metal is nonmagnetic.

Elenients must bi alloyed ,r (or mixed)together to obtain the desired physicalproperties of a metal. For example, alloying (ormixing) chromium and nickel with ironproduces a metal known as special treated steel.Special treated steel (STS) has great resistance topenetrating and shearing forces and is used forgun Adds, turrets, protective decks, and othervital areas. A nonferrous alloy that has manyuses aboarAhnip is copper-nickel, which is usedextensivel salt/ water piping systems.Copper-nickel is produced by mixing copper andnickel together. There are many other differentmetals and alloys used aboard ship which willnot be discussed here.

WitIVall the different types of sedaboard ship, so/ne way must be used to ide tifythese metals in the storeroom. At the p sent

,time, the Navy utilizes two syitem ofv identifying, metals: the continuous identifica

marking system and the color marking systein.

O

These systems have been so designed that venafter a portion of the metal has been re ovedthe identifying marks are still visible..

In the continuous identification . markingsystem, the identifying information is actuallypainted on the metal with a heavy ink. Thismarking appears at specified intervals over thelength of the metal..The marking contains theprOducer's trademark and the commercialdesignation of the metal. The marking alsoindicates the physical condition of the metalsuch as `;fold drawn," "cold rolled," "seamless,"and others.

In the color marking sy4em, a series of colorsymbols with a related color code is used toidentify metals. "Color symbol" refers to a colormarking actually painted on the metal. Thesymbol is composed of one, two, or three colorsand is painted on the metal in a conspicuousplace. These color symbols correspond to theelements of which the metal is composed.

For further information on the metals usedaboard ship, their properties and identificationsystems, refer to the Rate Training Manual, HullMaintenance Technician 3 & 2, NAVEDTRA10573.

36

CHAPTER 4

SHIP P

The primary, function Of any marineengineering plant is to convert the chemicalenergy off' a fuel into useful work and to utilize

4. that work in the propulsion of the ship. Apropulsion unit consists of the machinery andequipment, including their controls, which aremechanically, electrically, or hydraulicallyconnected to a propulsion shaft.

This chapter contains information on theprinciples of ship, propulsion Sand, in addition,acquaints you with some of the different typesof ship propulsiOn units, which include thegeared-turbine drive, the turboelectric drive,diesel electric drive and the:straight diesel.Anginedrive.

PRINCIPLES OFSHIP PROPULSION

A ship is propelled through the Water bymeans of some device which imparts velocity toa column of water and moves it in the directionopposite the direction in which it is desired tomove the ship. A reactive force (thrust) isthereby developed against the velocity-impartingdevice, and this thrust, when transmitted to theship, causes the ship to move through the water.All propelling devicesoars, paddle wheels, andpropellersare designed to move a column ofwater in order to build up a reactive forcesufficient to move the ship.

The screw-type propeller is the propulsiondevice used in practically all naval ships. Thethrust developed on the propeller is transmittedto the ship's structure by the *shaft through thethrust bearing. On most steam-driven ships, the

PULSION

31

37

/mechanical energy required to turn the propelleris provided by the turbines. Reduction sears areused on practically all Asteam-dOwn ships tbconnect the turbine to the shaft in a mannerthat allows the turbines to operate at highrotational speeds while the propeller operate atlower rotational speeds, thus allowing Mostefficient operation of both turbines andpropellers.

The general principle of ship propulsion isillustrated in figure. 4-1. O

TYPICALPROPULSION UNITS

Propulsion units with various types anddesigns of prime movers are currently in use innaval ships. The prime movers of a propulsionunit may be either a geared turbine a turbineand a generator, a diesel engine and a generator,or a straight diesel engine. These are the mostcommon types of prime` movers of propulsionunits with which we are most concerned.

GEARED-TURBINE DRIVE

In the geared-turbine drive, the unit parts orsections that make up the individual propulsionunits consist of the main turbines and thereduction gear.

Figure 4-2 shows the general arrangement ofthe turbines and gears in a geared-turbinepropulsion unit. Not all geared-turbine plants.have the cruising turb,me which is included inthe diagram. Ordinarily(, cruising turbines will befound in only the older destroyers.

01Ik FIREMAN

.4. MATERCOLUMN

STRUT (HAIN

SHAFTSPRING .

BEARINGS .

THRUSTBEARING

r

- STRUTING

PROPELLE

DIRECTION OFREACTIVE FORCE

(THRUST)

STERN TUBEBEARING

HULL

Figure 4-1.General principle of ship propulsion.

In a- typical destroyer propulsion plant, thespeed reduction ratio between the cruisingturbine shaft' and high pressure turbine shaft isapproximately 1.8 to 1. The speed jittio betweenthe high pressure turbine shaftd propellershaft is 16 to 1, and the ratio between the lowpressure turbine and propeller shaft is 13 to 1.In other words, in operation, if the propellershaft is revolving at 100 rpm, the cruising

1'

ASTERN ELEMENT

I TURBINEI LOW-PRESSURE

CRUISINGTURBINE

47.42

turbine will be revolving at 2,880 rpm (1.8 X 16X 100), the high pressure turbine at 1,600 rpm(16 X 100), and the low pressure turbine at1.,300 rpm (13 X 100).

Figure 4-2 shows two astern elements, one ateach end of the low pressure turbine. Thisarrangement is typical for combatant type ships;auxiliary type ships,%usually have one asternelement instead of two, and that one invariably

CRUISINGTURBINEREDUCTIONGEAR

HIGH -PRESS ETURB

MAINREDUCTION

GEARS

Figure 4-2.Geared-turbine propulsion unit.

32

MAIN SHAFT

47.1

Chapter P, PULSION

is located at the forward end of the low pressureturbine (the end\ farthest from the reductiongear).

The propulsion shaft, which extends fromain gear (lovi\speed) shaft of the reduction

gear to ropellCr, is supported and held, inalignment at the spring bearings, the stern tubebearings, and strut bearing. The axial thrust,acting, on She propulsion shaft as a result of thepushing effect of the propeller, is absorbed inth't main. thrust bearing. ,In most ships, the mainthrust bearing is located 'at the forward end ofthe main shaft, within the reduction gear casing.In some very large shipa however, the mainshaft thrust bearing is located farther aft in amachinery space or a shaft alley.

"I

-COMBINEDFIELDREVERSING -

LEVER

TUTt.BOELECTRIC DRIVE

urboelectric drive installations have a singleturbine unit for each installed shaft. Figure 4-1shows the diagrammatic arrangement of aturboelectric propulsion unit.: *you can see,the propuldtin unit includes a turbine, maingenerator, propulsion motor, and a propulsion-control board, a direct current generator forsupplying rotor field current to the proptilsionmotor and excitation current to the generator.Figure 4-4 is an illustration ofa tYpiC11 controlboard.

The speed reduction ratio between turbineand propeller in the turboelectric drive is,approximately the same as in the geared-turbinel

TURBINE SPEED leLEVER SPEED-

(AUTOMATIC CONTROL) GOVERNINGVALVES

STATOR

EMERGENCY S)3EEDLEVER

NILam,

MANUAL CONTROL.)

1 1.........,1"1" -----r-

DIRECT-;FIELDCURRENTi-i-:0-4-' GENERATOR

,___

TURBINE

MOT RPROPULSION

DRIVER MAINGENERATOR

GENERATOR-FIELDCONTACTORS

Figure 4-3.-Diagram of the turboelectric drive.

MAINCONDENSE

47.2

1. PHASE BALANCE RELAYS

2. GROUND PROTECTIVE RELAY

3. NAMEPLATE,FOR GEN FIELD AMP

4. EXCITATION SET STARTING SWITCH

5. TEST BLOCK

6. STANDBY EXCITER CONTROL SWITCH

ENGINE ROOM TELEGRAPH

8. CLOCK

9, GENERATOR FIELD AMMETER

10. TURBIN, SPEED INDICATOR

11. GENERATOR INDICATING WATTMETER

12. MOTOR FIELD AMMETER

13. EXCITER AND GROUND DETECTOR VOL TMETEFt

14. GENERATOR AMMETER

15. GENERATOR VOLTMETER

16. STATOR COIL TEMPERATURE INDICATOR

'7. INDICATING LAMP CONTROL BUS18. INDICATING. LAMP WRONG DIRECTION INDICATOR

19. INDICATING LAMP HEATER

20. EXCITER VOLTMETER,AND GROUND DETECTOR 04ITCH

21, CONTROL SWITCH ,

2Z, MOTOR-STATOR TEMPERATURE INDICATOR SWITCH

21 GENERATOR STATOR TEMPERATURE iNdICAtOR SWITCH

24. SHAFT RPM INDICATOR AND REVOLUTION COUNTER

21 SHAFT RPM INDICATOR AND REVOLUTION-INDICATOR

26. RPM TELEGRAPH

27. LOAD LIMIT CONTROL, RELEASE

28. LOAD LIMIT CONTROL HANDWHEQ.

29, EXCITER Fla.!) RHEOSTAT

30, MOTOR SET UP LEVER

31. FIELD LEVER

32. REVERSER LEVO1'

33. .GOVERNOR CONTROL LEVER,

34. EMERGENCY LEVER

35. TURBINE TRIP HANDLE ,\36. NAMEPLATE FOR EMERGENCY OPERATION

O

Figure 4-4.Propulsion control equipmentDE-51 class.

34

{f95

Chapter 4SHI USLION

4,

Figure 45 =Main propulsion diesel engine.

drive and is brought about electrically. Forexample, in one class of turboelectric drive typedestroyer escort, the normal operating rangefixed speed ratio between the turbine-generatorset and the propulsion motor is 14 to 1.

One of the outstanding differences betweengeared drive and electric drive is that the latterdoes not have an astern turbine element. In theelectric drive the direction of rotation of thepropulsion motor, and consequently thepropeller, is controlled' by the electrical switchset . Therefore, there is no need to reverseturbine rotation for astern operatio

DIESEL ELECTRIC DRIVE

Diesel electric drive is best suited to ships inthe low or mediurn horsepower range up toabout 6,000 shaft horsepower. It has beeninstalled in approximately 175 escort ships and5 00 surface ships and craft of other types,including minesweepers, submarine tenders,older submarines. fleet and harbor tugs, fuel oiltankers and barges, rescue and salvage craft andmiscellaneous unclassified craft.

35

41

139.10

Figure 4-5 shows one of the mein proptlsiondiesel engines aboard an oceanographic researchship. Figura. 4-6 shows the main prop4Isionswitchboard operating station aboard the sameship.

Si. The propulsion equipment for a fleet tugth4t utilizes diesel electric drive consists of fourdiesel-engine driven generators furnishing powerto one propulsion motor rated at 3,000horsepower which in turn drives the propeller.The four generating units are normally locatedamid-shipstwo on the port side and two on thestarbqard side.

The control of direction (forward or reverse)and the speed of propeller rotation isaccomplished at the control board. A typicalcontrol board installation aboard a fleet tug isshown in figure 4-7. O

In the propulsion plant's of .somediesel-driven ships, there is no mechanicalconnection ,between thkengine(s) and thepropeller(s). In such plants, the diesel enginesare connected directly to generators. Theelectricity produced by-such an engine-driven

sl

FIREMAN

J

Figure 4-6.main propulsion switchboard, unabated operating station. ,

generator is transmitted through cables to amotor. The motor is connected to the propellershaft directly, or indirectly, through a reductiongear. When a reduction gear is included in adiesel electric dnve, the gear is located betweenthe motor and the propeller.

The generator and the motor, of ,aelectric drive may be of the alternating current(a-c) type or of the direct current (d-c) type.Almost all diesel electric drives in the Navy,however, are of the direct current type. Sincethe speed of d-c motor varies directly with thevoltage fuAished by the generator, the controlsystem of an electric drive is so arranged that thegenerator voltage can be changed at any time.An increase or decrease in generator voltage isused as a means to control the speed of the

propeller. Changes in generator voltage may bebrought about by electrical means, by changes inengine speed, or by a. combination or thesemethods. The controls of an electric drive 'maybe in a location remote from the engine, such asthe pilot house.

4

In a d-c electric drive, a reverse gear cannot"be used to reverse the direction of rotation of

36

139.11

the propeller. The electric system is arranged sothat the flow of current through the motor canbe reversed. This reversal in the flow of current

I causes the rocitor to revolve in the oppositedirection. Thus, the direction of rotation of themotor and of the propeller can be controlled bymanipulating the electrical controls.

42

DIESEL ENGINE DRIVE

Diesel engine drive is used on various typesof auxiliary ships and craft such asminesweepers, subchasers, ammunition ships,patrol craft, landing ships (LST), and numerousother yard craft and small boats. You may alsofind diesel drive on a few of the older destroyerescorts.

The Navy uses the diesel engines exceptwhere special conditions favor the gasolineengine. Standardization of fuels, cheaper fuel,and reduction in fire hazards have been the chieffactors in favor of the diesel engine.

The diesel engine used in some of the olderdestroyer escorts developed approximately6,000 hp. The diesel engines of minesweepers

Chapter - 4SHIP PROPULSION

MS r M2 M3 15 MI

Dia3W$ GW2

=1RH1

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TELEGRAM

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MI- GENERATOR VOLTMETER, 500-0-500M2-EXCITER AND GROUND DETECTOR VOLTMETER, 100-0-100M 3 - AUXILIARY POWER AMMETER, 0- 2000M4 -MOTOR AND GROUND DETECTOR VOLTMETER, 1000-0 -1000MS-ENGINE SPEED INDICATOR, 0-1000M6 - MOTOR FIELD AMMETER, 0 -ISOM7 MOTOR AMMETER, 3000 -0 -3000M6 -PILOT HOUSE MOTOR AMMETER, 3000-0-3000 (NOT SHOWN)MO-EXCITATION VOLTMETER (SHIP'S SERVICE), 0-300

SWI -EXCITER VOLTMETER AND GROUND DETECTOR TRANSFER SWITCHSW2-AUXILIARY POWER GENERATOR FIELD CONTROL SWITCHSW3-MDTOR VOLTMETER AND GROUND DETECTOR TRANSFER SWITCHSW4 -EXCITER VOLTMETER AND GENERATOR FIELD GROUND DETECTOR TRANSFER SWITCHSWS-ENGINE SPEED -EXCITER FIELD SWITCH ON GENERATOR SET-UP SWITCH (NOT SHOWN)SW6-ENGINE SPEED CONTROL SWITCHSW7- EXCITATION CONTROL SWITCHSWEI -PILOT HOUSE-ENGINEROOM TRANSFER SWITCH

SW9.10-GENERATOR SET-UP SWITCHESSW11 -GENERATOR CONTROL SWITCHRHI -AUXILIARY POWER GENERATOR FIELD RHEOSTATRH2-MOTOR RELI) RHEOSTATPI -ENGINERODM CONTROLLER

Figure 4-7.-Propulsion control oquipment-floot tug.

4337

WRONG 0DIRECTIONINDICATOR .

CONTROLLER. pi

EMERGENCYSTOP

RELEASE

27.100

FiREIVIAN

and subchascrs will develop approximately1,800 hp; while some of the engines in thesmaller yzird craft will develop from 190 to 225hp. A typical dieselvengine 'is shown in figure4-8.

Sortie diesel engines are directly reversible.This means that the propeller shaft is connecteddirectly to the diesel engine, so that the speed ofthe propeller shaft is controlled by the speed ofthe diesel engine. When it becomes necessary tochange the direction of rotation of the propellershaft, the diesel engine must be stopped, thecam shaft of the engine must be shifted forreverse rotation, and then the engine is restarted.This allows the engine to operate in the oppositedirection; thus reversing the rotational direction

EXHAUST LIANIFOLD

of the propeller shaft. You can see that thiswould take time and be very hard to do ifsudden changes in direction were required.

To eliminate this stopping-starting situationand to make a smoother transition from forwardto reverse in less time, reverse-reduction gears,clutches, and hydraulic couplings are used.(These are discussed in the following sections ofthis chapter.)

CONVERTINGPOWER TO DRIVE

The basic characteristics of a propulsion unitmake it necessary, in most instances': for the

SCAVENGING AIR INTAKESILENCER

SCAVENGING AIR BLOWERS

GEAR BOX

PROPELLERDRIVE HUB

REVERSING CLUTCH

SUBBASE

44Figure 4-8.Typical dieml engine and reduction gear.

38

REVERSINGCONTROL

75.44X

r

Chapter 4 --SHIP PR PULSION

CRUISING TURBINE

SINGLE REDUCTIONGEAR

HIGH PRESSURETURBINE

1st. REDUCTIONGEAR

t3

444 LOW PRESSURETURBINE

QUILL SHAFT

-.Tr.--,==.10t. REDUCTIONGEAR

2nd. REDUCTIONPINION

JACKING MOTOR a /GEAR ENCASED-1

2nd. REDUCTIONGEAR

MAIN SHAFT COUPLING

Figure 4-9.Titrbine and locked train double reduction gearing installed on a DD-692 class destroyer.

drive mechanism to change both the speed andthe direction of shaft rotation. In order thatboth the engine and the propeller may operateefficiently, the engine in many installationsincludes a' device which permits a speedreduction from the engine to the propeller shaft.This device, which is a combination of gears and

39

47.30

hich effects the speed reduction, is called aduction gear.

DUCTION GEARS

45

Turbines must operate at relatively ighspeeds for maximum efficiency, where

FIREMAN

propellers must operate at lower speeds formaximum efficiency. Reduction gears are used,therefore, to allow both the turbine and thepropeller to operate within their most efficientrevolutions per minute (rpm) ranges. A typicalreductio4gear illustration is shown in figure 4-9.

The use of reduction gears is by no meanslimited to ship propulsion. Other steamturbine-driven machinery, such as ship's servicegenerators and various pumps, also has reductiongears. In lese units of machinery, as well as inshipboard propulsion units, turbine operatingefficiency requires a higher rpm range than thatsuitable for the driven unit.

Reduction gearing in many currentcombatant ships makes use of double helicalgears. The use of 41ouble helical gears produces asmoother actiqn,to,of the reduction gearing andavoids tooth shock. Since the double helical gearhas two sets of teeth at complementary angles toeach other, the end thrust, such as developed insingle helical gears, is thereby eliminated.

Reduction gears are classified by the numberof steps used to bring about the speed reductionand the arrangement of the gearing. A gearrriechanism consisting of a pair of gears or asmall gear (pinion) driven by the turbine shaft,which drives a large (bull), gear on the propellershaft directly, is called a SINGLE REDUCTIONGEAR. In this type of arrangement the ratio ofspeed reduction is proportional to the diameterof the pinion"and the gear. For example, in a 2to I single reduction gear the diameter of thedriven gear is twice that of the driving pinion;and in a 10 to 1 single reduction gear, thediameter of the driven gear, is, 10 times that ofthe driving pinion.

Ships built since 1935 have DOUBLEREDUCTION PROPULSION GEARS. In thistype of gear, 4--Ngh-speed pinion, connected tothe turbine shill' by a flexible coupling, drivesan- intermediate (firstjeduction) gear which isconnected by a shaft to the low-speed pinion;this, in turn , drives the bull gear (secondreduction) mounted on the propeller shaft. Forexample, a 20 to 1 (6000-300) speed reductionmight be accomplished by having a ratio of 2 to1 (6000-3000) between the high-speed pinionand the first reduction gear, and a ratio of 10 to1 (3000-300) between the low-speed pinion on

40

4V

the first reduction shaft and the secondreduction gear on the propeller shaft

(6000 + 2 = 3000 + 10 = 300).

For a typical example of a double reductionapplication, let us consider the main reductiongear installation on a DD-692 class destroyer,shown in figure 4-9.

The cruising turbine is connected to the-highpressure turbine thrOugh a single reduction gear.The cruising turbine rotor carries with it apinion which drives the cruising gear (coupled tothe high pressure turbine shaft). The cruisingturbine rotor and pinion are supported by three.bearings, one at the forward end of the turbineand one on each side of the pinipn in thecruising reduction gear case,

The high pressure and low pressure turbinesare connected to the propeller sh.. through alocked train type double reduction"Year, shownin figure 4-10. (Note: This type of reductiongear is used aboard many naval combatantships.) First reduction pinioni are connected byflexible couplings to the turbines. Each of thefirst reduction pinions drives two first reductiongears. A second reduction (slow speed) pinion isattached to each of the first reduction gears by aquill shaft and flexible couplings. These four

tow PRESSURE Is,REDUCTION MON

WON PRESSURE In.EDUCTION PINION

LOW PRESSURE 1stREDUCTION GEARS tow Pansto1 2.4

SEDUCTION PIN*MAIN

EAR

NON PRESSURE IltSEDUCTION GEARS

HIGH PRESSURE NoREDUCTION PINIONS

Figure 4-10.Locked-train typo gearing.47.27

Chapter 4SHIP PROPULSION

pinions drive th second reduction (bUll) gearwtich is atta to the propeller shaft.

CLUTCHES ANDREVERSE GEARS

Clutches are normally used on direct-drivepropulsion engines to provide a means ofdisconnecting the eivi" from the propellershaft. In small enginei clutches are usuallycombined with reverse .gears and are used formaneuvering the ship. In large engines specialtypes of clutches are used to obtain specialcoupling or control characteristics and toprevent torsional (twisting) vibration.

Reverse gears are used on marine engines toreverse the direction of rotation of the propellershaft, during maneuvering, without changing thedirection of rotation of the engine. They areused principally on relatively small engines. If ahigh - output engine has a reverse gear, the gear isused for low-speed operation only and does nothave full-load and full-speed capacity. Formaneuvering ships with large direct-propulsionengines, the engines are reversed.

Diesel propelling equipment on -a boat or aship must be capable of providing backing-downpower as well as forward power. There are a fewships and boats in which backing down isaccomplished by reversing the pitch of thepropeller; in most ships, however, backing downis accomplished by reversing the direction ofrotation of the propeller shaft. In mechanicaldrives, reversing the direction of rotation of thepropeller shaft may be accomplished in one 9ftwo ways; by reversing the direction of.enginerotation or by using the reverse gears.

The drive mechanism of a ship or a boat isrequired to do more than reduce speed andreverse the direction of shaft rotation. It isfrequently necessary to operate an enginewithout having power transmitted to thepropeller. For this--feason, the drive mechanismof a ship or boat must include a means ofdisconnecting the engine from the propellershaft. Devices which are used for this purposeare called clutches.

The arrangemeni\ of the componentsdepends on the type and size of the installation.In some small installations, the clutch, thereverse gear, and the reduction gear may becombined in a single unit; in other installations,the clutch and the reverse gear may be in onehousing and the reduction gear in a separatehousing attached to the reverse gear housing.

To large engine installations, the clutch andthe reverse gear may be combined; or thy maybe separate units, located betweerk the engineand a separate reduction gear; or the Clutch maybe separate and the reverse gear may becombined.

In most geared-drive, multiple propellerships he propulsion units are independent ofeach Other. An example of this type ofarrangement is ill9strated in figure 4-11.

In some installations the drive mechanism isarranged so that two or more engines drive asingle propeller. This is accomplished by havingthe driving gear, which is onor connectedtothe crankshaft of each engine, transmitpower to the driven gear on the propeller shag.In one type of installation, each of twopropellers is driven by four diesel engines (quadpower unit). The arrangement of the engines,the location of theduction gear; and thedirection of rotation of the crankshaft and-ttieprokpeller shaft in one type a "quad" powerunit are illustrated in figure14 2.

The drive mechanism' illustrated includesfour clutch assemblies (One mounted to eachengine flywheel) and one gear box. The boxcontains two drive purns and the main -drivegear. Each pinion is driven by the clutch shaftsof two engines, through splines in the pinionhubs. The pinions drive the single main gear,which is connected to the propeller shaft.

Friction clutches are commonly used withsmaller, high-speed engines, up to 500 hp.However, certain friction clutches, incombination with a jaw type clutch, are usedwith engines up to 1,400 hp; and pneumaticclutches, with a cylindrical friction surface areused with engines up to 2,000 hp.

41

47'

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8

Chapter 4SHIP PROPULSION

Figure 4-12.Four engines (quad unit) arranged to drive one propeller (GM 6-71).

Friction clutches are of two general styles;the disk and the bank styles. In addition,friction clutches can be classified as dry or wettypes, depending on whether the frictionsurfaces operate with or without a lubricant.The designs of both types are similar, exceptthat the wet clutches require a large friction areabecause of the reduced friction coefficientbetween the lubricated surfaces. The advantagesof wet clutches are smoother operation and lesswear of the friction surfaces. Wear results fromslippage between the surfaces not only duringengagement and disengagement, but also, to acertaip extent, during the operation of themechanism. Some wet type clutches are filledwith oil periodically; in other clutches the oil isapart of the engine-lubricating system and iscirculated continuously. Such a friction clutchincorporates provisions which will preventworn-off particles from being carried by thecirculating lubricating oil to the bearings, gears,etc.,

The friction surfaces are generallyconstructed of different materials, one being ofcast iron or steel; others are lined with someasbestos-base composition or bronze for dry

43

49

75.249X

clutches, and bronze, cast iron, or steel el for wetclutches. Cast iron surfaces are preferred becauseof their better bearing qualities and greaterresistance to scoring or scuffing.

Force-producing friction is needed to engagethe frictiopclutches and can be obtained eitherby mechanically jamming the friction surfacestogether by some toggle-action linkage, orthrough stiff springs (coil, leaf, or flat-disktype). The operation of friction clutches isdiscussed in the paragraphs which follow.

TWIN-DISK CLUTCH AND GEARMECHANISM.One of the several types oftransmissions used by the Navy is the GrayMarine transmission mechanism. Gray Marinehigh-speed diesel engines are generally equippedwith a combination clutch and a reverse andreduction gear unitall contained in a singlehousing at the after end of the engine.

The clutch assembly of the Gray Marinetransmission mechanism is contained in the partof the housing nearest the engine. It is a drytype, twingdisk clutch with two driving disks.Each disk is connected `through shafting to aseparate reduction gear train in the after part of

FIREMAN

the housing. One disk and reduction train is forreverse rotation of the shaft and propeller; theother disk and reduction train is for forward'rotation.

JOE'S CLUTCH AND REVERSE GEAR.Atypical gear mechanism found on many powerboats is Joe's clutch and reverse gear, shown infigure 4-13. The drive from the enginecrankshaft is taken into the clutch and reversegear housing by an extension of the crankshaftdrive gear. The crankshaft rotation istransmitted to the reduction gear shaft throughthe clutch and the reverse gear unit.

AIRFLEX CLUTCH AND GEARASSEMBLY.On the larger diesel-propelledships, the clutch, reverse, and reduction gearunit has to transmit an enormous amount of

DISK CLUTCH

PLUNGER

TOGGLE ASSEMBLY

(dialr31

power. To maintain the weight and size of themechanism as low ossible, special clutcheshave been designed or large diesel installations.One of these is e airflex clutch and gearassembly used with General Motors 12-567Aengines on LST's.

A typical airflex clutch and gear assemblyfor AHEAD and ASTERN rotation, is shown infigure 4-14. There aLe two clutches, one forforward rotation and tone for reverse rotation.The clutches, bolted to the engine flywheel,both rotate with the engine at all times at enginespeed. Each clutch has a flexible tire (or gland).on the inner side of a steel shell. pefore the tiresare inflated, they will rotate out of contact withthe drums, which are keyed to the forward andreverse drive, shafts. When air under pressure(100 psi) is sent into one of,the tires, the inside

BEARING, CAGE

CONE CLUTCH

r FRONT COVER

ENGINESHAFT

COLLARAND YOKE

REDUCTION /GEAR SHAFT-lk>. BRAKE

BANPROPELLER PINION GEARDRIVE. SLEEVE LONG)

PINION GEAR( SHORT )

DRUMENGINE SLEEVE

75.254Figure 4-13.attaway view of Joe's clutch and reverse gear:

44

5

MAIN GEAR

Chapter 4SHIP PROPULSION

D CLUTCH

PROPELLERFLANGE

AIR CONTROL HOUSING

AHEAD

MAIN REVERSE PINION

FO WARD DRUM

SPACER

IR SHAFT

FORWARD PINION

REVERSEDRUM REVERSE

CLUTCH

REVERSESHAFT

ASTERN

REVERSE STEP-UP PINION 75.247Figure 4-14.Clutch and ie verse-reduction gear assembly.

diameter of the clutch decreases. This causes thefriction blocks on the inner tire surface to comein contact with the clutch drum, locking thedrive shaft with the engine.

HYDRAULIC CLUTCHES ORCOUPLINGS.The fluid clutch (coupling) iswidely used on Navy ships. The use of ahydraulic coupling eliminates the need for amechanical connection between the engine andthe reduction gears. Couplings of this typeoperate with a small amount of slippage.

Some slippage is necessary for operation ofthe hydraulic coupling, since torque is

45

51

transmitted because of the principle of relativemotion between the two I'otors. The power lossresulting froWehe small amount of slippage istransformed into heat which is absorbed by theoil in the system.

Compared with mechanical clutches,hydraulic clutches have a number of advantages.There is no mechanical connection between thedriving and driven elements of the hydrauliccoupling. Power is transmitted through thecoupling very efficiently (97 percent) withouttransmitting torsional vibrations, or load shocks,from the engine to the reduction gears. This

FIREM

TRAILINGEDGE

CONNECTED TO CRANksitAFT

CONNECTED TO pRopEsAER

Figure 4-15.Dog clutches.

! ADIN,OGL

ROOT

A

HUB

TRAILINGEDGE

FACE

FORWARD

DIRECTIONOF ROTATION

AFT

by solid lines, the propeller IsWhen blades ore In Position shown

driving the vessel ahead. Whenblades ore in position shown bybroken line the propeller isdriving the vessel astern.

139.56Figure 4-17.Schematic diagram of a controllable

75.264 pitch propeller.

RAKEANGLE

LEADINGEDGE

Figure 4-16.Propeller blade.

B

BACK

147.46

protects the engine, the gears, and the shaftingfrom sudden shock loads which may occur as aresult of piston seizure or fouling of thepro eller. The power is transmitted entirely bythe circulation of a driving fluid (oil) betweenra la' passages in a pair of rotors. In addition,th 'assembly of the hydraulic coupriiig willa sorb or allow for slight misalignment.

D 0 G, C L UTCH E S . Dog-type clutchesperform much the same function as the friction

46-'-52

type in that they allow the engine shaft to bedisconnected from the propeller shaft. The dogclutch ensures a positive drive without slippageand with a minimum amount of wear. (Forwarddrive is generally accomplished by one set ofdogs, shown in figure 415, connected to thecrankshaft, engaging and turning another set ofdogs, connected to the propeller shaft.)

In several installations, theftiog clutch is usedin addition to a friction clutch; the dog clutch isengaged after the friction (or synchronizing)clutch brings the two shafts to an equal speed.The engagement of the dog clutch eliminatesslippage and holds friction clutch wear to aminimum.

PROPELLER

The screw-type propeller consists of hub andblades (usually three or four) all spaced at equalangles about the axis. When the blades areintegral with the hub, the propeller is known asa SOLID propeller. When the blades areseparately cast and secured to the hub withstuds, the propeller is refetred as a BUILT-UPpropeller.

Some of the parts of the screw propeller areidentified in figure 4-16. The FACE (or pressureface) is the afterside of the-blade when the shipis moving ahead. The BACK (or suction back) isthe surface opposite the face. As the propeller

Chapter 4SHIP R,ROPULSION

rotates, the face of the blade increases pressureon the water to mekve tt in % positive asternmovement. The overall thrust, or reaction forceahead, comes from the it cr!ted water velocitymoving astern.

The TIP of the blade is' the most distantfrom ,the hub. The ROOT of the blade is thearea where the blade joins the hub. TheLEADING EDGE is the edge which first cuts thewater when the ship, is going ahead. TheTRAILING EDGE (also called the followingedge) is opposite the leading edge.

A RAKE ANGLE, exists when the tip of thepfopeller blade is not precisely perpendicular tothe axis (hub). The angle is formed by thedistance between where the tip really is (orward

t.

53

47

or aft) and where the tip would be if it were inperpendicular position.

A screw propeller may be broadly classifiedas FIXED PITCH OR C TR LLABLEPITCH. The'pitch of a ed pitch p pellercannot be altered during peration; the p tch ofa controllable pitch pro eller can be dh ged atany time, subject to bridge or engineroomcontrol. The controllable pitch propeller canreverse the direction of a ship without requiringa change of direction of the drive shaft. Theblades are mounted sd that each one can swivelor turn on a shaft which is mounted in the hub,as shown in figure 417. Most propellers in navalships are of the fixed pitch type, but somecontrollable pitch propellers are in service.

CHAPTER 5

BASIC STEAM CYb.ES

In a dition to knowing hav steam, isgenerate , you must know what happens tosteam af er it leaves the boiler. One of the bestways to learn about the'steam plant on yourown ship is to trace the path of steam and waterthroughout its entire cycle of operation. In thischapter, the main steam cycle and the auxiliarysteam.cycle are discussed. In each of these cycles

the e.!water and th steam circulate'throughoutthe entire cycle of operatiOn Vithout eVeribeingexpbsed to the atmosphere.:.,

A discussio follows or the four basicreasof operation in steam cycle, shown, in figure5-1: part Agener tion; part Bexpansion; partCcondensatio nd part 15feed.

,.***"amewom doom .0* 4 ...Nom am.. 1.0100 0101 .. :IMMO Wry. INIMM

1 I A GENERATION

IL ER';,.

1B EXPANSIONCRUISING, TURBINE

I I

I I

1.1)GH

PRESSURETURBINE

girERtiF ATE?

%.331.111.111.111..A.

..i1'..1%1*;

.10110IN..; =NM* 111.1. j

,0.4/0Mi

I

IMAIN FEEDPUMP'

FEEDa BOOSTER

PUMP

I I

I

.1 I AIREJECTOR

IS CONDENSATED FEED01111.11 m.o.. oar.= aa.o.

CONDENSATEPUMP .

ONO..

Figure 8.1.Diagrammatic, arrengement (the main steam cycle.

48

11110111M, =1.

38.2

Cha;ter SBASIC STEAM CYCLES

MAT STEAM CYCLE

GENERATION'

To generate steam, it is first necessary toheat water to its boiling point and then add asufficient amount of heat to change (convert)the boiling water into steam. The heat. requiredto change boiling water into steam, at any giventemperature of. the boiling water, is called thelatent heat of vaporization. When steamcondenses back to water (at boiling point), anequal amount of heat is given off; it is called thelatent heat of condensation. The amount of heatrequired to convert boiling water to steam, orthe amount of heat given; off when steam iscondensed, back to water at -its boilingtemperature, varies with the pressure underwhich the Kocess takes place. Part A of figure5-1 illustrates the generation area of the cycle.

There are definite pressure-temperaturerelationships involved in the generatioh ofsteam. The boiling point of water is 212° F atsea level, where the atmospheric pressure is 14.2psi., At higher altitudes, where atmosphericpressure is reduced, water boils at a . lowertemperature. If the pressure is increased, theboiling temperature of water will also beincreased. In a boiler operating under a pressureof 600 psig, water must be heated toapproximately 48° F. to make it boil. In boilersoperating under a viciressure of 1000 psig, watermust be heated to approximately 544° F tomake it boil. Therefore, the boiling point ofwater is determined by the pressure.

It is important to note that the temperatureof steam is determined by the temperature atwhich the water boils, as long as the process istaking place in a closed vessel or in a closedsystem such as a boiler. As long as the pressureremains constant, steam in contact with thew&ter from which it is being formed mustremain at the same temperatuit as the ,boilingwater. Therefore, in a boiler operating under apressure of 600 psig, the temperature of thegleam in the stem drum must be approximately489° Fthe, same temperature as the boilingwater. (The tsteam drurn,of the boiler is a sealedchamber that holds tne., water and steam.)

49

The` -steani in the steam drum is calledSATURATED STEAMthis is steam which hasnot been heated above the temperature of thewater from which it was generated. Saturatedsteam Is used aboard ship to operate most of theauxiliary equipment and also in the varioustypes of heaters.

It is impossible to raise the temperature ofsaturated steam without also increasing thepressure as long as the steam is in contact withthe water from which it is formed. However, thesteam can be heated above its saturationtejnperature if it is first drawn off into'anothervessel, where it is no longer in contact with thewater, and if additional heat is applied. Steam'which has been heated aboye its saturationtemperature is known as SUPERHEATEDSTEAM. The device which allows this extra heatto be added to the steam is known as aSUPERHEATER. Figure 5-2 shows a simpleform of both a boiler and a superheater.

55

Most naval propulsion 'boilers are equippedwith superheaters. Superheated steam has manyadvantages over saturated steam for use inpropulsion machinery. Because the steam is dry,it causes relatively little corrosion or erosion ofpiping and machinery. In addition, superheatedsteam does not conduct heat as rapidly assaturated steam; therefore, it does not lose heatas rapidly. The use of superheated steam forpropulsion purposes greatly increases the overallefficiency of the engineering plant; thisincreased efficiency results in large savings infuel consumption, and in space and weightrequirements.

Since most auxiliary machinery is designedto operate on saturated steam, naval boilers aredesigned to produce both saturated and 'superheated steam.

EXPANSION

The expansion portion of the main steamcycle is that part of the. cycle in which steam isled from the boilers to the main turbines andexpanded in those turbines to remove the heatenergy stored in the steam and to transform that

FIREMAN

FEED WATER

SATQRATED. fsunntiu401sT.EAm

GENERATINGFURNACE

SUPERHEATERFURNACE

Figure 5-2.Elementary boiler and superheater.

THERMOMETER CONNECTION

OVERBOARD DISCHARGE

RECIRCULATING .

CONNECTION

ZINC PLATE

AUXILIARY EXHAUST EXHAUST STEAMSTEAM INLET INLET

AIROUTLET

VACUUM ,

CONNECTION

VE T THERMOMETERCONNECTION

IMPINdEMENT BAFFLE

TUBE SUPPORT/

FIBERBRINGS

METALLICRINGS

TUBE END DETAIL

AIRBAFFLE

HOTWELL

1!P

rfr

HOSECONNECTION

LUKE OILCOOLER r

CONNECTION

CIRCULATINGPUMP

CONNECTION

CONDENSATEOUTLET SCOOP INLET

Figure 5-3.Cutaway view of a main condenser.

50

56

47.70X

Chapter 5BASIC STEAM CYCLES

energy into mechanical energy of rotation. Themain steam system is the piping system whichleads the steam from the boilers to the mainturbines.

The 'main turbines generally consist of thecruising turbine, high pressure turbine, and thelow pressure turbine: The steam may flow intothe cruising turbine, then to the high pressureturbine and on into the low pressure turbine; orthe cruising turbine may be bypassed. Somemain turbine installations do not have a cruisingturbine. Part B of figure 5-1 illustrates theexpansion portion of the main steam cycle; itcontains the cruising turbine, high pressureturbine, and low pressure turbine.

CONDENSATION

Since each ship must produce sufficientquantities of feed water for the boilers and sincea marine engineering plant must be as efficientas possible, the feed water must be used overand over again.

As the steam leaves or exhausts from the lowpressure turbine, it enters the condensatesystem. The condensate system is that part ofthe steam cycle in which the steam condenses to

AUX. STEAM

FIRST STAGEAIR EJECTOR

SECOND STAGEIN EJECTOR

water and flows from the main condenser (fig.5-3) toward the boilers while it is being preparedfor use as feed water.

The several components of the condensatesystem, in sequence, from the low pre ureturbine are: (1) main condenser, (2) gincondensate pump, and (3) the main, air ejector.(See fig. 54.) These components are shown inpart C of figure 5-1.

The main condenser receives the steam fromthe low pressure turbine and condenses thesteam into water. The main condensate pumptakes suction from the main condenser anddelivers the condensate into the condensatepiping system and through the main air ejector.As its name implies, the air ejector removes theair that was picked up in the main condenser.The condensate, after passing through the airejector, enters the vent condenser section of thedeaerating feed tank before entering the tank.

FEED

The deaerating feed tank (fig. 5-5) issometimes considered as the dividing linebetween condensate and feed water. This tank

AFTERCONDE SER

VENT TOATMOSPHERE

(VIAEXHAUST FAN)

AUX. STEAM

EXHAUST VEN'T

GLANDEXHAUST

STEAM11P.

CONDENSATEPUMP

INTERLOOP CONDENSERREAL

DRAIN

TOD AERATIND

TANK

GLANDEXHAUST

CONDENSER

CD CONDENSATEGn VAPOR1=1 STEAM

Figure 5-4.Flow diagram of a two-stage air ejector.

51

47.77X

FIREMAN

RECIROLATION.

AIROUTLET(

SPRAYVALVES

WATERINLET

VENT.CONDENSER

OEAERATINGUNIT

1ga

21,AIM10,14'.

_

toOree'eee INA

WATER OUTLET

Figure 5-5.Deaer tited tank.

5852

STEAMI INLET

HIGHPRESSURE

CtiECK.VALVE

CONTROL

38.17

a

Chapter 5 BASIC STEAM CYCLES

has three basic functions: (1) to free thecondensate of all trapped oxygen and air, (2) toheat the water to a degree which will allow theeconomizer to introduce all the remainingnecessary heat before discharging it to thebeater, and (3) to act as a reservoir in which tostore water to take care of rapid increases infeed needs and to absorb sudden' increases or

rges of the condensate.

As the condensate enters the deaerating feedtank,-it is sprayed into the dome of the tank bynozzles: Here it is discharged in a fine 'spraythroughout the steam-filled top or preheater.The break up of the condensate into a fine sprayreleases the trapped oxygen and air from thecondensate. The air-free, oxygen-free condensatefalls to the bottom of the tank, while the air andoxygen are exhausted from the tank.

, The condensate that is collected in thestorage section of the deaerating feed tank isnow called feed water and becomes a source ofsupply for the main feed booster pump. Themain feed booster pump takes suction from thedeaerating feed tank and maintains a constantdischarge pressure to the main feed pump.

The main feed pump picks up the water(delivered from the booster pump) anddischarges it into the main -feed piping system.Part D of figure 5-1 illustrates the path of thewater from the deaerating feed tank to theeconomizer. The discharge pressure of the'mainfeed pump is usually about 150 psi greater thanthe boiler operating pressure. For example, thedischarge pressuce of, a main feed pump,Aft charging to a Oiler operating at 600 psi, willnormally be 750,..01. The discharge pressure ismaintained throughout the main feed piping

system; however, the quantity of waterdischarged to the economizer is controlled by afeed stop arid check valve or automatic feedwater regulator valve.

The economizer is positioned on the boiler'to perform one basic function; that is, to act as apreheater. The gases of combustion flow aroundthe economizer tubes hich absorb some of theeat of combustion, an the economizer in turn

heats the water that is flowing through the

economizer tubes. As .a result the water isapproximately 100° F hotter as it flows out ofthe economizer to the boiler.

AUXILIARY STEAM CYCLE

The generation spction of the auxiliarysteam cycle is the same as the main steam cycle.The main difference is that the auxiliary steamdoes not go through a superheater. Therefore,the auxiliary steam in all cases is a saturatedsteam.

Another difference occurs between thegeneration and expansion sections. Note that infigure 5-6, the line that carries the steam to theauxiliary equipment (where expansion takesplace) has a number of lines leading to variouspieces of equipment such as main feed pumps,main feed booster pumps, main condensatepumps, main tube oil pumps, and steam reducingvalves, just to name a few pieces of equipment,serviced by the various fap offs. In the mainsteam cycle, only the main turbines are servicedby the main steam line. Another majordifference is that after 'expansion has takenplace, the exhaust steam does not go directlyinto the main i5r auxiliary condenser (fig. 5-7)but goes into an auxiliary exhaust header andthen to either the main or auxiliary condenservia an unloading valve (fig. 5-8). Normally, inport the auxiliary steam plant will be used. Theunloading valve associated with the plant that isin operation will be used. The unloading valvemaintains about 10-15 pounds of exhaust steam

42, pressure on the exhaust steam header for plantefficiency.

The condensation section of the steam cycleis the same process in both the main andauxiliary steam cycles. The system where saltwater is used in a heat ,exchanger (main orauxiliary condenser) tto turn the low pressure orexhaust steam back tccondensate for future useis called a conderming section. The basicdiffIrence is that the main condenser will'notalwrys be used as a heat sink in the auxiliarysteam cycle. As stated before, in most cases inport you will be using the auxiliary condenserand the associated auxiliary equipment will beused to operate the auxiliary steam plant.

53

59

FIREMAN

2 OtGR** =tom 2 FtR2 ROOM i worm wpm FIRE ROOM

AostSio.

Ljt 0.1to 4 O... 0.4

t *trot.

nini

Figure 8-6.Adicillary steam system.

GENERATC$,TURIINE EXHAUST INLE

THERMOMETER CONHECTIO

tr

DETAIL OF TUBE ENDS

GENERATOR TURBINEEXHAUST INLET

CIRCULATING CONNECTION STRAINER

DEM OPERATED

CONDENSATE OUTLET

RELIEF VALVE..r." CONNECTION}-:VIPH. WATER

:11 `'-"" OUTLET

FEED TANK VENT

EXPANSION JOINT

CONDENSATE PUMP VENT

AIR EJECTOR SUCTION

EVAPORATOR DRAIN

0.1 MAKE UP CONNECTION

FEED WATER THERMOMETER

WATER INLDRAIN TANK VENT CONNECTION

Figure 5-7.Auxiliary condenser.

54

6Ob

30.18

47.71

Chapter 5BASIC STEAM CYCLES

GAT VALVE

.-/TILNJILm 'r 0,1LifilUNLOADINGVA VE

7"

'1

$TR INER

'A*

DIAPHRAGM

NUM.*E1Y-PASSVALVE MPH AGM

R SEALDIAPHRAGMSPRING

MANUAL CONTROLVALVE WHEEL

4

Figure 5- 8.- -Swartwout unloading valve.

The feed system is the same with one majordifference, that is, in port an auxiliary feedbooster pump (electric driven) can be usedinstead of the main feed booster punip to takesuction on the deaerating feed tank. This

61

55

ADJUSTINGSCREW

47.61

auxiliary pump can be used to supply the headof water to the emergency feed pump (areciplTating pump) instead of the main feedpump which, in turn, will feed the water backto the boilers to be converted back to steam.

CHAPTER 6

BOILERS

This chapter gives you basic information onboilers and operating principles. We shalldiscuss boiler c nstruction and the major partsand their f ctions. Also, you will findnumerous fire oom safety precautions whichmust be observed when boilers are being fired.

BOILER ASSEMBLY

A boiler is that part e s eam cycle inwhich water is Converted nto steam. The boilerconsists of me al drum eaders and tubes, andaccessories fo con ing steam pressure andtemperature :nd other aspect*, of boileroperation. Y ,u ill also find a furnace withcasing and u ake; steam and water drums;generating, circulation, and water screen tubes; asuperheater; an economizer; and the necessarypiping and accessories to ensure an ample supplyof fuel, water, and air.

A cutaway view of a D-type boiler is shownin figure 6-1. As we continue our discussion onboiler assembly, imagine that you are assemblinga similar boiler. As you add each part to yourboiler, follow the line drawing that describes theposition of that part.

The steam drum (fig. k-2) is a cylinder,located at the top of the boiler, and it runslengthwise _from the front to the back of theboiler. The steam drum provides a space for theaccumulation of steam generated in the tubesand for the separation of moisture from thesteam./It also sery s as a storage space for boilerwater, which is tributed from the steam 'drumto the down mer tubes. (During normaloperatiA, the steam dram is kept about half full

of ater.) In Addition to these basic functions,th steam drum either contains or is connectedto many of the important controls and fittingsrequired for the operation of the boiler.

)At the bottom right side of the boiler youwill find thewater drum and on the bottom leftside is another drum, the header,, or sidewallheader, shown in figure 6-3. The waterdrum islarger than the header, but both are smaller thanthe steam drum. They equalize the distributionof water to thegerieiatirig tubes and collect thedeposits of loose scale and other solid matterwhich may be present in the boiler water. Thedrum and header each has a blowdown valve.When the valve is opened, some of the water isforced out of the drum or header and carries theloose scale, sediment, or dirt with it.

At each end of the steam drum are a numberof large tubes (fig. 6-4) that lead to the waterdrum and sidewall header. These tubes are thedowncomers through which water flowsdownward from the steam drum to the waterdrum and the header. The downcomers rangediameter from 3 to 8 inches.

A great number of other tubes also link thesteam drum to the water drum and the steamdrum to the header. The several rows of tubesthat lead from the steam drum to the waterdrum are the generating tubes (fig. 6-5) whichare arranged in the furnace so the gases and theheat of combustion can flow around them. Thelarge arrows in figure 6-5 show the direction offlow of the combustion gases.

The generating tubes are made of steel thatis strong enough to withstand the high pressures

56

62

Chapter 6 BOILERS

'SURFACE BLOW 1

I OXFFL E MATERIAL I

I AIR !m.o.!.

PLASTIC CHROME ORE I

I SUP.ERNEATER

124. INSULATING OLOCK

11% SPLIT INSULATING BRICK)

IVSPLIT FIREBRICK

Ff

!FEED WATER OUTLET)

PEED WATER'INLET

I Me PLASTIC FIREORICK

[MS FIREORICK

11,14" INSULATING FIREBRICK!

V INSULATING OLOCK 1

?IS FIREBRICK

2/3"INSULATING FIREORICK

I l'INSULATING BLOCK )

weoLOortSOT

L.tca:14ItTiplAL

INSULATING BLOCK

PLASTIC CHROME ORE )

38.40Figure 6-1.Cutaway view of a D-type boiler (older type).

6357

FIREMAN

SIDE VIEW

Figure 6-2.Steam drum.

END VIEW

139.13

BOTTOMBLOW DOWN VALVE

139.14

Figure 6.3. Steam drum, water drum and header.

and te peratu es within the boiler. In mostboilers these to are usually 1 to 2 inches indiameter, but there may be some that are 3inches. These small tubes present a large surfacearea to absorb the heat in the furnace. Note thata 2-inch tube has twice the surface area of a1-inch tube, but four times the volume. A 3-inchtube has 3 times the surface area of a 1-inchtube, but 9 times the volume. The smaller the

. diameter of the tube, the higher is the ratio ofabsorption surface to the volume of water.

Normally there is only one row of generatingtubes leading from the steam drum to the Figure 6-5.Adding generating tubes and furnace area.

T~7 7i

OOWNCOMERS

139.15Figure 6-4.Addition of downcomer tubes.

OOWNCOMERS

139.16

58

64

Chapter 6BOILERS

sidewall header. These are the sidewall (waterwall) tubes which provide, a cooling effect toprotect the side wall of the furnade.

So far we have assembled the drums, header,downcomers, and the generating tubes. Beforegoing any further with the assembly, let us tracethe path of the water through the boiler. Thewater flows out of the steam drum downthrough the downcomers into the water drumand the sidewall header. As the water is heated itforms a vapor (steam) that is lighter than thewater in which it is contained. The steam risesthrough the generating tubes and returns to thesteam drum. The arrows in figure 6-6 show thecirculation path of the boiler water as it leaves 4.the steam drum and as it returns to the steamdrum as steam.

The furnace, or firebox (fig. 6-5) is the large,room-like kpace where air and fuel are mixed forthe combustion of the fuel (fire). The fire heatsthe water that is in the drums, tubes, andheaders.

1

COOLER WATERFLOWS DOWN

MIXTURE OfHOT WATERAND STEAMFLOWS UP

HOTGASES

139.17Figure 6-6.--Natural circulation (accelerated type).

59

6 5

38.40Figure 6-7.Refractory lined furnace.

The furnace is more or less a rectangularsteel casing which is lined on the floor, frontwall, side walls, and rear wall with refractory(heat resisting) material. Refractory materialsused in naval boilers include firebrick, insulatingbrick, plastic firebrick, and air-setting mortar.

The refractory lining protects the furnacesteel casing and prevents the loss of heat fromthe furnace. The refractories retain heat for arelatively long period of time and thus help tomaintain the high furnace temperatures that areneeded for complete combustion of the fuel.Figure 6-7 shows a refractory lined furnace.

There are many different types ofrefractories. Each type is used according to itsphysical and chemical properties whichdetermine the refractory's location within thefurnace. Some refractory materials canwithstand greater temperatures than others andare positioned nearer to the intense heat of thefire.

In chapter 5 you discovered that aneconomizer is positioned on the boiler (fig. 6-8)where it acts as a pre-heater. It absorbs heat

FIREMAN

0 0010000 0 0

139.18

Figure 6-8.Relative position of economizer.

11.1P1.4eqleitittiliiii

ittirkt

,"14t1i1110141!"

A 1:111 LIU

38.28Figure 6-9.U-bend economizer tube with aluminum

gill rings.

from.the furnace and transmits this heat to theincoming feed water. The economizer is madeup of a number of tubes which are illustrated infigure 6-9. The fins on the tube absorb the heatItom the gases of combustion and in tarntransfer the heat to the incoming feed water.

60

One more basic component is needed tocomplete the water-steam flow path-. From yourstudy of the steam cycle do you remember whatthat"' component might be? In chapter 5 youwere told that the steam, as it leaves the steamdrum on its way to the main turbines, passesthrough a superheater.

The superheater (fig. 6-1Q) is constructed af)

a number of U-shaped tubes which are insta edhorizontally projecting forward into the furnace.The superheater tubes are connected to thesuperheater headers which are installed verticallyat the rear of the boiler; one end of the tubeenters one header and the other end of the tubeenters the other header. (Some supeIheaters areof the vertical type with horizontal headers.)

The superheater tubes are positioned inthe boiler that they are SUff0 nded by thegenerating' tubes. They are also pla d so the hotgases of combustion flow over and arou d them.Figure 6-11 shows the relative position of thesuperheater tubes installed -irr the boiler. Youhave now assembled the major parts of theboiler. Look again at the assembled boiler shownin figure 6-1. Identify the component parts andreview their functions.

FUEL OIL BURNERS

Now that you have assembled the majorcomponents of the basic boiler, you are ready toinject the fuel and air into the furnace wherecombustion takes place. Look at the fuel oilburners that are mounted on, the boiler front(fig. 6-12). The complete burner assemblyconsists of the atomizer, the air registers, andthe valves and fittings needed to connect theatomizer to the fuel line.

ATOMIZERS

The atomizers divide or break up the fuel oilinto very fine particles as illustrated in figure6-13. There are three major types of atomizersin use on naval boilers. Straight-through-flowatomizers are found in the est shi s. Thereturn-flow atomizers (fig. 6-13) used onmany of the newer ships; you may also findsteam-aisist atomizers on some cof the newerships.

66.

Chapter 6BOILERS

SUPERHEATER .HEADERS

SUPERHEATERTUBES

ItIt PASS

2nd PASS

VENT

rd PASS

SUPERHEATEDSTEAM

OUTLET

B

SUPERHEATERHEADERS

SATURATEDSTEAMINLET

DRAIN

DRAIN DRAIN

Figure 6-10.Diagrammatic arrangement of superheater.

ECONOMIZER

I \i©©©©!©C)

©@ OC)i ®@ ©®160 ©©I t©©0©

//WATER

,,,/wATER WALL /463TUBES /Jo/1

/ors/SUPER-

/c HEATER/4. / TUBES/0 '/

/ // i/GENERATINGTUBES

SIDE WALLHEADER WATER DRUM

38.39Figure 6-11.Relative position of superheater tubes.

4-

38.23

61

6 7

38.70Figure 6-12.Babcock an d Wilco aroline -type fuel

oil burners installed on a boiler front.

FIRQAN

ORIFICEPLATE

tt'AfrAe

SPRAYERPLATE

ATOMIZER DISTRIBUTOR NOZZLEHEAD BODYNUT

.14 11111111111111111141111111,

101 OMAHA iy .r-.5414A112"17

dint".4111111illIll 11101 11111111lilimi, ' /7, /f.nektklatitkav

OIL LEAVING WHIRLING OIL RETURN OILe° ORIFICE CHAMBER SUPPLY

Figure 6-13.Return-flow atomizer.

ATOMIZERBARREL

38.75

Figu)re 6-14 shows an atomizer of thestraight through -flow 'type. It consists of fivemajor Parts: the tip, sprayer plate; nozzle,burner b\a,rrel, and the gooseneck. The nozzle,sprayer plap, and tip assembly fit on the end ofthe burner barrel which projects into thefurnace. The gooseneck fits on the outer end ofthe burner barrel. Fuel oil enters the atomizerassembly through the gooseneck and is sprayedinto the furnace.

AIR REGISTERS

Air enters the furnace through the airregister where it mixes with the fine oil spraywhich entered through the atomizer. Figure 6-15shows the arrangement of air register part's in aburner assembly. The air register consists ofthree main parts: (1) air doors, (2) a diffuser,and (3) air foils. The air doors are used/to openor close the register as necessary. They areusually kept either, fully opened or fully closed.When the air doors are open, air rushes"fn and isgiven a whirling motion by the diffuser plate.The diffuser plate causes the ,air to rpix evenlywith the atomized oil in such a wa g/. that theflame will not blow away from the atomizer.The air foils guide the major quantity of air sothat it mixes with the larger particles of oil spraybeyond the diffuser.

Oil is forced under pressure through theburner barrel. It goes through "the holes in thenozzle (fig. 6-16A) into the tangential grooves ofthe rear side of the sprayer plate (fig. 6-16B).

I GOOSE NECK IIATOMIZER

ASSEMBLY

[NOZZLE

I SPRAYER PLATE'.

38.71Figure 6-14.Parts of a straight-through-flow

atomizer assembly.

These grooves are so shaped that the oil is given'a high rotational velocity as it discharges into asmall cylindrical whirling chamber in the centerof the sprayer plate.

The whirling chamber is cone-shaped at theend and has as opening (orifice) at the small endof the cone. The oil leaves the chamber throughthe orifice and is broken. up into very fineparticles to form a cone-shaped fog-like spary. Astrong blast of air, which has been given awhirling motion in its passage through theregister, catches the oil fog and mixes with it.The mixture of air and oil enters the furnacewhere combustion takes place.

CLASSIFICATION OF BOILERS

Naval boilers may be classifr.d in a numberof different ways, according to various designfeatures. Some knowledge of these methods ofclassification will help you understand the

- design and construction of modem naval boilers.

62

68

LOCATION OF FIREAND WATER SPACES

_First of all, boilers are classified according tothe relative location of their fire and water

Chapter 6BOILERS

INNER CASING

STATIONARY I

AIR FOILS

t BURNER OUTER CASINGBARREL

II AIR DOOR HANDLE

BURNER CONE OPENING I i<

INNER CASING

=1....:=W41)..4 a II V "se

's.sizzY9pyOW -NIA

114

YOKE

GOOSE NECK

AIR (;.:IOR HANDLE

DIFFUSERPLATE.

BURNER (SIDE VIEW)

DISTANCE PIECE

MOVABLE AIR DOORS

OUTER CASING (BOILER FRONT)

BURNER BARREL

BURNER COVER PLATE

BURNER (FRONT VIEW)

ATOMIZER VALVE

Figno 6-15.Cross-sectional view of Babcock and Wilcox Carolina-type fuel oil burner withsCeight-through -flow atomizer.

-6963

Air

re

38.69

FIREMAN

NOZZLEHOLE S

DISHED ANDROUNDED FACE

A

FLAT FACE

:Mt

7J

Figure 6-16.Nozzle and spreyor plate showing holos, groove and whirling chombor.

spaces. By this method of classification, allboilers may be divided into two groups:fire-tube boilers and water-tube boilers. InFIRE-TUBE BOILERS, the gases of combustionflow through the tubes and heat the surroundingwater. In WATER TUBE BOILERS, the.,:waterflows through the tubes and is heated by thegases of combustion that fill the furnace.

All boilers used in propulsion plants of navalships are water-tube boilers. Fire-tube boilers,which were once used extensively in marineinstallations, are still used in propulsion plants

64

70

38,/2X

of some older merchant ships. However, theseboilers are not suitable for use on modern navalshipsecause of their excessive weight and size,the excessive length of time required to raisesteam, and thAjnability to meet demands forrapid speed chitges./

TYPES OF CIRCULATION

Water-tube boilers are --also classifiedaccording to the type of circulation. Naturalcirculation boilers are those in which the

411,'

Chapter bBOILERS

circulation of water depelids on the difference indensity betWeen a rising mixture of hot waterand steam,.and a falling body of relatively cool,steam-free -water: The difference in densityoccurs because the water expands as it is heated,thus becoming less dense. There are two types ofnatural circulationfree and accelerated.

In. FREE CIRCULATION BOILERS, thetubes which connect the lower and upper drumsor headers are 'only slightly inclined to allow the

-lighter hot water and steam to rise while theheavier and cooler water descends. Installing thegenerating tubes at a greater angle of inclinationincreases the rate of water circulation.Therefore, boilers.in which the tubes slope moresteeply between the water drums or headers andthe steam drum are ACCELERATEDCIRCULATION BOILERS.

Most modern naval boilers are designed foraccelerated natural circulation. In such boilers,large tubes (3 inches or more in diameter) areinstalled between the steam drum and the waterdrums. We discussed, these large tubes, the

wdowncomers when we assembled the boilerearlier in this chapter. The .downck:rri l'ers, arelocated outside the furnace (fig. 6-1) and awayfrom the heat of combustion, thereby serving aspathways for the downward flow of relativelycool water. The small tubes, the generatingtubes, then carry the steam and water upward.

TYPE OF SUPERHEATER

Oi practically all boilers currently used inthe propulsion plants of naval ships, thesuperheater tubes are protected from radiantheat by water screen tubes. These tubes absorbthe intense radiant heat of the furnace, and thesuperheater tubes are heated by convectioncurrents rather than by. direct radiation. Hence,the superheaters are referred to asCONVECTION-TYPE SUPERHEATERS.

On some older boilers, the superheater tubesw re not screened by water screen tubes butwe e exposed directly to the radiant heat of thefu ace. Superheaters of this type are calledR DIANT-TVPE SUPERHEATERS. Although

65

this type of superheater is uncommon at thepresent time, it may be used again in futureboiler designs.

FURNACE ARRANGEMENT

Aknatuml circulation boilers now in navaluse may also be classified according to thefurnace arrangement. By this classification,boilers are either SINGLE-FURNACE BOILERSor DOUBLE-FURNACE BOILERS.Double-furnace boilers are also referred to asDIVIDED- FURNACE BOILERS.

OTHER NAVAL BOILERS

There are many different kinds of boilersused in naval ships. Earlier in this chapter yc5ustudied and assembled the 600 psi D-type boiler.The other boiler used in naval ships is the 1200psi boiler shown in figure 6-17. Ngtice that thisboiler is very similar to the boiler shown infigure 6-1. However, the boiler in figure 6-17 hassome special operating and design features whichmake it' different from the one shown in figure6-1. A relatively new boiler that is presentlyinstalled on some new constructico of the DE1040 class ship is the pressure fired boiler shownin figure 6-18. Since the pressure fired boiler isused for propulsion only, those ships that have arffssure fired boiler installed also have anauxiliary boiler.

Auxiliary boilers are not generally used onseam -driven ships tbecaute, all steam forauxiliary service is taken from thepropulsion-plant boilers. Auxiliary boilers are awide variety of small boilers that are used indiesel -driven ships to supply steam or hot watetfor distilling plants, space heating, galley andlaundry services. Auxiliary boilers contain theirown accessories and controls and operate as acomplete self-contained unit. The three basictypes of auxiliary boilers in naval use are (1),fire-tube boilers (fig. 6-19), (2) water-tubeboilers with natural circulation (fig. 6-20), and(3) water-tube boilers with faced circulation(fig. 6-21).

. Generally, operating pressures of auxiliaryboilers range from 50 psi to 125 psi. Most

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I I s

O 11

Chapter 6BOILERS

139.19Figure 6-18.Pressure fired boiler.

67

FIREMAN

1 r

Figure 6-19.Fire-tube auxiliary boiler.

operating and maintenance procedures for mainpropulsion boilers are also applicable toauxiliary boilers.

NEW HIGH-PRESSUREBOILERS

The modern trend in boiler design is towardhigher 'Pressures and temperatures. High pressureboilers are smaller, lighter, and more economicalin fuel usage, in any given shaft horsepower,

68

4

139.20

than boilers which operate at lower pressuresand temperatures. Boilers operating at 4500 psiand above are now, in use in some stationarysteam power plants. For naval propulsionboilers, such pressuKs are not practicable at thepresent time. However, a number of boilers,operating at 1200 psi pressure and at 950° F,have been installed on new naval ships.Increasing use of these boilers will be made.

A HIGH-PRESSURE BOILER is any boilerthat operates at 700 psi or above. TheHIGH-PRESSURE, D-TYPE BOILER is

.7-

/Chapter 6- BOILERS

Figure 6- Assembly view, water-tube auxiliary boiler (natural circulation).

69

t)

139.21

FIREMAN

139.22Figure 6-21.Amernbly view, water-tuba auxiliary

boiler (forced circulation).

natural circulation boiler that is the same as theD-type boiler, wept that it has been modifiedfor higher operatin g pressures.

FIREROOM SAFETY° PRECAUTIONS

Safety precautions are for your protection aswell as for the protection of machinery andequipment. When working in a steamingfireroom, 'you should be fully clothed. Thevalves, pipes and exposed metal in flrerooms arealways hot and'will burn the flesh and leave ascar. Not only should you keep your shirt on,but you should also keep your shirt sleevesrolled down. Whenever you are assisting inlighting off or securing boilers, or just generallyworking in the fireroom, pay strict attention toposted safety precautions and to those

i`

precautions that your petty officers will- tellyou.

A few important safety precautions arelisted here; your petty officers will instruct youin many more:

1. Do not open or close any valve you arenot told to open or close.

2. Do not play games of any kind in thefireroom.

3. Do not leave tools lying around thefireroom; always return them to their properstowage.

Observe the following precautions whenlighting off a boiler:

I. Remove stack cover.

2. Run the water level down until it isbelow lighting off level and, then, add waterwith the emergency feed pump until it is atlighting off level.

3. Always purge the f e before lightingoff the first burner.

4. Stand well cl ar when inserting andwithdrawing the torch.

Observe the following precautions duringboiler operation:

I. Never leave disconnected atomizers inplace. /

2. Keep the atomizer root valves closed tosecured burners, except during maneuvering.

3. Test the drain from the oil heater onceeach hour.

4. Blow through the gage glasses once eachwatch.

5. Poke through the burner drain holesonce each watch.

6. Wipe up spilled oil at once. -/-*/

7 670

Chapter 6BOILERS

Observe the allowing safety precautionswhen securing a boiler:

1. In shutting down a fireroom, do notclose the master oil valve until the fuel oil pumpis secured,

2. Remove atomizers from registers as soonas -possible after securing.

3. Close all openings to the furnace as soonas all atomizers have been extinguished.

4. Pump the water level to three-fourthsglass on cutting out a boiler,

7 7

71

CHAPTER 7

STEAM TURBINES AND REDUCTION GEARS

We have discussed the basic steam cycle andvarious turbine propulsion units. In this chapterwe shall discuss the components insde the casingof the turbines and reduction gears so that youwill have a basic understanding of how thestored energy (heat) in steam is transformed intothe mechanical energy (work) of rotation.

TURBINES

The development of steam power was builtaround the reciprocating engine; however, theearliest steam engine operated on the TURBINEprniciple. Almost 2,000 years as Hero, a Greekmathematician built a small steam turbine anddemonstrated that steam power could be used tooperate other machinery (fig. 7-1). Hero'sturbine consisted of a hollow sphere whichcarried four bent nozzles. The sphere rotatedfreely on two tubes that carried steam from theboiler. Steam generated iu the boiler passedupward through the tubes and into the sphereand out through the nozzles. As the steam leftthe nozzles, the sphere rotated rapidly.

Down through the ages the turbine principlehas been applied to many different types ofmachines. The water wheel that was used tooperate the flour mills in colonial times, thecommon windmill used to oump water, and thetwo-bladed windmill Used to charge batteries are

.all examples of the turbine principle. In theseexamples the power is derived from the effect ofthe wind or a stream of water on a set of bladesattached to a wheel. In the steam turbine,steam under pressure serves the same purpose asWe %Lind or the flowing water in the other types.

72

78

CLASSIFICATION OF TURBINES

Turbines may be classified in four ways:

1. By the manner in which the steam causesthe turbine rotor to rotate.

2. By the type of staging and compoundingof steam pressure and velocity.

3. By the division of the steam flow.4. By the direction of the steam flow.

Figure 7- .Hero's steam Turbine.139.23

(

Chapter 7STEAM TURBINES AND REDUCTION GEARS

Under each of these classifications, there areseveral types of turbines, some of which aredescribed briefly in the following paragraphs.

pulse Turbines ,

The energy to rotate an impvilse turbine isderived from the kinetic energy of a steam jet orsome other rapidly moving fluid. The term"impulse" means that the force which turns theturbine comes from the impact of the rapidlymoving fluid. The toy pinwheel (figl 7-2) can beused to study some of the basic principles ofturbines. When you blow on the rim of thewheel, it spins rapidly. The harder you blow, thefaster it turns. The steam turbine operates onthe same principle, except that instead of the airyou were blowing, it uses the high pressuresteam from the ship's boiler.

The impulse turbine consists essentially of arotor or spindle mounted on a shaft that is freeto rotate in a set of bearings. The outer rim ofthe spindle carries a set of curved blades, and thewhole assembly is enclosed in an airtight case.Several nozzles direct the steam against thebladespd turn the spindle (fig. 7-3).

STEAM NOZZLES (hereafter referred to asnozzles or stationary blades) are connected tothe line that carries high pressure steam from theboiler. As the steam passes through each nozzle,

139.24Figure 7-2.The toy pinwheel operates on the impulse

turbine principle_

3

79

NOZZLE NO.4

Figure 7-3.A simple impulse turbine.33.46

its pressure is reduced, but its velocity is greatlyincreased. The potential energy of the steamunder pressure is converted to kinetic energy inthe high-speed jets emerging from the nozzles.These jets are directed against the turbine bladesand turn the spindle. 'In other words, thevelocity of the steam is reduced in passing overthe blades, and some of its kinetic energy istransferred to the blades as a force to turn thespindle. The modern impulse turbine operateson the same general principle as the model justdescribed, but it has many refinements.

COMPOUND TURBINES have several rowsof revolving blades with stationary nozzles orblades mounted between each row. As the steampasses throukh the first stage, it moves faster inthe nozzles and slows down while going throughthe moving blades. The second set of nozzlesspeeds the steam up again, making additionalkinetic energy available for the second row ofmoving blades. This sequence continues throughall of the successive stages until ate pressure is

,,)

FIREMAN

139.25Figure 7-4.A velocity compounded impulse turbine

with a reduction gear.

reduced -to the point that it would not beeasible to take any more energy from it.

The velocity compound impulse turbineshow in figure 7-4 has two rows of movingblades. Steain enters through the inlet, flowsthrough the governor valve, and passes throughthe stationary nozzles. The steam undergoes alarge pressure drop and a large velocity increaseout of the nozzles. The steam then enters thefirst row of moving (rotor) blades, attached tothe rotor where there is a de ease in velocity. Itthen flows through the stationary blades orguide blades. There is neither a pressure dropnor a velocity increase while the steam goesthrough the stationary blades. The stationaryblades, attached to the turbine casing, merelyprovide a place for the steam to reverse its flowbefore it enters the next row of moving blades.The steam then enters the second row of movingblades where there is also a decrease in velocity.The velocity is so reduced that by the time tiesteam reaches the exhaust, molsk of the energyhas been used to turn the spindle.

The shaft of the spindle revolves in bearingssupported by the turbine casing. Carbon packing

-------STEAMCHEST

EQUALIZINGHOLE

SHAFTGLAND

NOZZLE

/ / /----0smA

EXHAUST

ROTOR

KEY.

tFaaaan.t t

%ri/iirrr

1,0,10

0..1110,1

Figure 7-5.Impulse turbine.

SHAFTGLAND

38.78X

rings keep the steam from escaping through tieshaft bearing. We shall discuss the reduction gearshown on the turbine in figure 7-4 later in thechapter. It consists of a pinion gear (attached tothc spindle shaft) an4a much larger bull gear.Because of its larger diameter, the bull gearrotates much more slowly than the high-speedturbine.

Impulse turbines are used in the Navy todrive the forced draft blowers and most of thefeed water and fuel pumps. They have fewmoving parts, are lightweight, do not take upmucKace, and run with very little vibration.

In an impulse turbine, a STAGE is defined asone set of nozzles and the succeeding row orrows of moving and fixed blades. Another wayto define a stage is that is includes the nozzlesand blading in which only one pressure droptakes place. (In an impulse turbine, remember,the only pressure drop takes piaci in thenozzles. Therefore, the number of sets ofnozzles in an impulse turbine indicates thenumber of stages.)

74

s0

.1.1.11111111.1r11,11,..

Chapter 7STEAM TURBINES AND REDUCTION GEARS \

EQUALIZINGHOLE

SHAFTGLAND

ROTOR

SHAFTGLAND

/pr:, ,,,;., .1 0. , /

1111It

38.79XFigure 7-6.Velocity-compounded impulse turbine.

Figure 7-5 shows a SIMPLE IMPULSETURBINE. This turbine has one stage, consistingof one set of nozzles and 6ne row of movingblades mounted on the rotor. Simple impulseturbines do not completely utilize the velocityof the steam, and are therefore not veryefficient.

One way to increase the efficiency of asingle-stage impulse turbine is to add anotherroerar even two more rows) of moving blades-to the rotor wheel. Figure 7-6 shows a turbinewhich has two rows of moving blades. This typeturbine is a VELOCITY-COMPOUNDEDIMPULSE TURBINE because the loweredvelocity of the steam leaving the first row ofmoving blades, is used in the second row ofmoving blades; and, if a third row iS added, theadditionally lowered velocity of the steam isused again in the third row. The fixed blades,which are fastened to the casing rather than t

Qfrom lthe rotor, serve only to direct the steam froArione row of moving blades to another.

Another way to increase the efficiency of animpulse turbine is to arrange two or more simple

impulse stages in one casing. The casing .isinternally-divided by diaphragms which containnozzles so that the residual steam pressure ofone stage is utilized in the following stage.. Thistype of turbine is known as aPRESSURE-COMPOUNDED IMPULSETURBINE because a pressure drop occurs ineach stage, as the steam expands through eachset of nozzles. Figure 7-7 shows apressure-compounded impulse turbine with fourstages.

Reaction Turbines

The ancient turbine built by Hero operatedon the reaction principle. Hero's turbine wasinvented long before Newton's time, but it was aworking model of Newton's third law of motionWhich states: FOR EVERY! ACTION THEREMUST BE AN EQUAL AND OPPOSITEREACTION. On first thought, you may find itdifficult to accept this statement on its facevalue. However, let us look at some moreunderstandable samples of Newton's theory.

If you set An electric fan off a roller skate, itwill take off across the table (fig. 7-8). The fanpushes the sir forwArd and sets tip a breeze(velocity); the air is also puShing backward onthe fan with an equal force, but in an oppositedirection. You enjoy- Th*1:k breeze that is blowing

75 ,

it

38.80XFigure 7- 7. Pressure-compounded impulse turbine.

FIREMAN

139.26Figure 7-8.The reaction of the air on the bladg

rolls the electric fan across the sable.

139.27Figure 7-9.A toy balloon demonstrates the7' "kickback" or reaction principle.

from the front of the fan, but the breezeproduces an opposite force on the back side ofthe blades to move the fan backward.

When yOu try to push a car, you may notknow it but, you are pushing back with yourfeet as hard as you are pushing forward withyour hands. Try it scimetime when you arestanding on an icy road. You will not be able tomove the car . unless you Ikon dig in with yourfeet to exert the backward force. With a littlethought on your part you should be able tocome up with enough examples to prove toyourself that Newton's third law .of motionholds true under all clidumstances.

The reaction turbine uses the reaction of asteam jet to drive the spindle. You have learned

that in an impulse turbine the nozzles increasethe velocity of the steam and transform thepotential energy of the steam under pressure

Li into kinetic energy in the steam jet. A forwardforce must be applied to the steam to increaseits velocity as it passes through the nozzle. FromNewton's third lawoof motion you have seenthat the steam"jet everts a force on the nozzleand an equal reactive force on the turbine bladesin the opposite direction; this is the force thatchives the turbine.

9 768 2

In the reaction turbine, stationary bladesattached to the turbine casing act as nozzles and-direct the steam to the moving blades. Themoving blades are mounted on the rotor. Mostreaction turbines have several stages, withalternate rows of stationary and moving nozzleblades.

The "kickback" or reaction force generatedby the nozzle blades can be demonstrated by atoy balloon. Blow up the balloon and toss it intothe air. The air will rush out through theopening and the balloon will shoot off in theopposite direction (fig. 7-9).

YWheri you fill the balloon with air, you havertate,ntial energy in the increased air pressureinside. When you let the air escape it is speededup (velocity) as it passes out, through the small,opening; this represents a transformation frompotential to kinetic energy. The force applied tothe air to speed it up is accompanied by areaction in the opposite direction. This reactiveforce propels the balloon forward through theair.

You probably think that the force thatmakes the balloon move forward comps from,Ole jet of air blowing against the air in the room,but this is not so. It is the reaction of the forceit talfes to increase the velocity (speed) of the airas it papes out through the - opening. Theballoon would .travel even faster if'it were in avacuum. Try it the next time you are near aballoon.

.The reaction turbine (fig. 7-10) has tall theadvantages of the impulse'type turbine, plus aslc&ver operating 4speecl and greater efficiency.

Chapter 7STEAM TURBINES AND REDUCTION GEARS

The several stages through which the steampasses gradually reduce the steam pressure untilpractically ,off of the energy has been convertedto power. When a reaction turbine is operated inconjunction with a condenser,. the exhaustpressure of the turbine is only a smAll fraction ofthe normal atmospheric pressure. The steamgradually expands as it passes through thesuccessive stages. Therefore, the length of theblades is increased in each succeeding stage totake care of the additional volume of steamcaused by this expansion.

Brkfly, let us compare- the impulse turbineand the reaction turbine. In the impulse turbineyou learned that the steam pressure dropsONLY in the nozzles.

In the reaction turbine,-the steam pressure,drops 'successively in each row of bladeswhether fixed or moving. The combination of arow of fixed blades and a row of moving bladesin these .turbines is sometimes referred to as aDOUBLE STAGE (also known as a singREACTION STAGE).

All reaction turbines are pressure'-ornpounded. The PRESSURE-COMPOUNDEbREACTION TURBINE has alternate rowsr-or'stages, of fixed and moving blades, which

LOW PRESSUR ELEMENT

ASTERN ELEMENT

139.28XFigure 7-10.A low pressure Peaction turbine with

the upper half of the case removed. ar

77

compound the total pressure drop into as manysteps as there are rows of fixed and movingblades. This pressure staging lowers the steamvelocity in each stage.

CONSTRUCTION OF TURBINES

Other than the contrcls, similar turbine partsare found in both the impulse,and the reaction

turbines, slick! as foundations, casings, nozzles(or stationary blades), rotors, Movabli blades,bearings, shaft glands, and gland seals.

Foundations

Turbine foundations are built up from astructural foundation in the hull to provide arigid supporting base. All turbines are subjectedto varying degrees of temperaturefrom thatexiling during a secured condition to thatexistir g during full-power operation. Therefore,

jtame means 'must be provided to allow forexpansion and contraction.

Normally., the after end of the turbine isfirmly secured by bolts to the structuralfoundation. The bolts have shanIts which arefitted to the exact size of the holes in whichthey are placed. The tight fit thus preventsmotion of any kind.

At the forward end of the turbine, there aretw9 ways to give freedom of momement. Eitherelongated bolthbles or grooved sliding seats areused so the forward ena bf jhe turbine can movefore and aft, as eithei expansion or c_9traction,respectively,yikes piaci.

Casings

Turbine -casings are generally constructed ofcast carbon steel. However, for tukbines that usesuperheated steam with temperaWires of morethan 65091Vonthe 'casings are generally cast orfabricated from carbon molybdenum steel orchromium molybdenum steel. Each casing has asteam chest to receive j the incoiliiir highpressure steam which it.delivers to the" first set'of rrozzles ots blades.

0

FIREMAN

Nozzles

The primary funs n of the, nozzles is toconvert the thermal energy of steam into kineticenergy. The secondary function of the nozzles isto direct the steam against the blades. In mostmodern turbines the Rozzles are made up intogroups or blocks with each group beingcontrolled by a separate nozzle control valve.The amount of steam delivered to each stagethus becomes the function of each of thenozzles and nozzle control valves in each groupor block. A diagrammatic arrangement of anozzle group is shown in figure 7-1-1 .

Rotors

Rotors (forged wheels and shaft) are Madeof carbon steel when used with

, when the:s)team of

relatively low temperatures. Howevtemperature of the steam will be greater than650° F, the rotors are made of carbonmolybdenum of some uther creep- resistantalloy. In all types of turbines, the primarypurpose of the rotor is to carry- the movingblades which receive the energy from the steamto turn the turbine shaft. A rotor without theblades is shown in figure 7 -I 2.

NOZZLECONTROLVALVES

Movable Blades

The blades are secured to the turbine casingsand rotors b' various methods. Some ¶f themethods of securing turbine blading areillustrated in figure 7-13, parts A through D. Thestraight circumferential dovetail (part A). isprimarily" used to secure rotor bladei. Theinverted circumferential dovetail (part B) is used

' to secure blading in most impulse turbines. Theside-locking key piece method (part C), which isused only on casing blades, consists of driving alocking key piece between the blade root and agroove in the casing. The sawtooth serrationmethod (part D) is used for both rotor andcasing blades.

Bearings

The rotor of every turbine must besupported in bearings, which serve a (Jou*purpose. The bearings ( I) carry the weight ofthe rotor and (2) maintain the corsed radialclearance between rotor and casing. AU mainturbines, and most auxiliary units, have abearing at each end of the rotor.

Bearings are generally classified as slidingsurface (sleeve and thrust) or as rolling contact(antifriction).

All propulsion and most auxiliary turbineinstallations are equipped' with sleeve bearings,which ark of two types: cylindrical and

+lb

Figure 7-11.Diagram of a nozzle group.-47.13X

78

84

47.15XFigure7-12.Turbine motor l4ithout tllades.

Chapter 7 STEAM TURBINES AND REDUCTION GEARS

LOCKINGKEY

PIECE

CAULKING PIECE

TURBINECASING

N.4

R

F `

BLADE

WHEEL

BLADE

WHEEL

LABYRINTHSHROUDING

Figure 7-13.Methods of securing blading.

el

79

CASING

ROTOR

77;4f//4,>%

FIREMAN

esm

OUTLe TS, TOSIGHT FLOW ANDTHenuomeren DAM

DRAINS

UPPER HALF

98.3XFigure 7-14. A typical propulsion turbine joumcl

bearing.

spherical-seated. A typical cylindrical journalbearing is shown in figuie 7-14.

THRUST BEARINGS take care of any axialthrust, which may exist in a turbine rotor, andalso hold the turbine rotor within certain'definite axial clearances. Thrust bearings areinstalled on all main turbines on one end of the

is

139.29XFigure 7-15.Assembled thrust bearing element.

I

turbine, usually just forward of the forwardturbine bearing. A thrust bearing is also installedon the propeller shaft either at the forward endof the main reduction bull gear or in thepropeller line shafting abaft (behind) the gear, totake the thrust of the propeller. Except that thepropeller thrust bearing is' much larger, thedesign of turbine thrust bearings and propellerthrust bearings Much the same. Some thrustbearings are lubricated by the sane lubricatingoil system which suptIlies oil tO-kthe turbine

-- bearings and reduction `gears. Some )ships haveseparate thrust bearings aft of the reductiongear; this arrangement has its own lube oilsystem. An assembled thrust bearing element isshown in figure 7-15.

80

86

Rolling Contact (antifriction) bearingsinclude ball and roller bearings which are usedott some small auxiliary units.

Shaft Glands

Shaft glands are used to prevent leaking ofsteam from the turbine casing at the pointswhere the shaft extend through the casing. Theshaft glands on auxiliary turbines. have a glandhousing which may be either a part of theturbine casing or a separate housing bolted tothe, casing. Two types of packing are

1=7_IA0)10104. I:.3 pi..

PACKINGSTRIPOR FIN

CARSBLOCK I t

PAOtI G CKINGRING

SHAFT

10 ola

0

Nr,...\. ....\ "'AO.. KEY

11 41°-

SHAFT

Mr= Ma= -0

47.17X .Figure 7- 16. Turbine motor shaft glands:

A. Labyrinth packing gland; B. Carbon packing gland..

I

Chapter 7STEAM TURBINES AND REDUCTION GEARS

usedlabyrinth packing and carbon packing,which may be used either separately or incombination. ;

Labyrinth packing, shown in figure 7-16A,consists of rows of metallic strips or fins. Thestrips are so fastened to the gland liner thatthere is a very small space between the strips andthe shaft. As the steam from the turbine casingleaks through the small space between thepacking strips and the shaft, steam pressure isgradually reduced.

Carbon packing rings, shown in figure 7-16B,restrict the passage of steam along the shaft inmuch the same manner as do the labyrinthpacking strips. Carbon packing trigs aremounted around the shaft and held in place bysprings. Three or four carbon rings are generallyused in each gland. Each ring is fitted into aseparate compartment of the gland housing, and,each ring consists of two, three, or foursegments which are butt-jointed to each other.These segments are held together by a garterspring. Keepers (lugs or stop pins) are used toprevent rotation of the carbon rings when theshaft trott--e(s. The outer carbon ringcompartleht is\connected to a drain line.

Carbon packing is suitable only for relativelylow pr ssures and temperatures. Therefore,when bath types of packing are used in onegland, thel labyrinth packing is used at the initialhigh-pressure area and the carbon packing isused at the low pressure area.

Gland Sealing System

Steam is passed into the glands to seal theglands of the turbines and to prevent air frombeing drawn into the condenser. Thelow-p re turbine, which operates at all timeswith a, va um in its casing, must have steamadmitt at .11 times to the glands from someextern s ce. This steam is led from theauxiliary xhaust line to pass through a cutoutvalve, n through a weight-loaded pressureregulating valve to the 'turbine glands. Theweight-loaded pressure regulating valve operatesat all times to maintain a pressure of 1/2 to 2 psi

87

GLANb SEALING STEAMAT 2 poi

SHAFT

47.10XFigure 7-17.A turbine steam reading gland.

1(15 to 17 pounds absolute) to the turbinesealing glands (fig. 7-17). In high-pressure andcruising turbines at higher speeds, the pressureon the turbine end of the forward glands will beso great that steam will bleed out through theseglands, automatically sealing them. Since theseglands may at times seal themselves, it isnecessary to have a separate system for thecruising and the high-pressure turbifies.

REDUCTION GEARS

In Chapter 4 we discutsed the mainpropulsion locked-train type, double-reductiongaring used in the DD-692 class destroyer. N,",let us consider the main propulsion,double-reduction gearing.

MAIN PROPULSION,DOUBLE-REDUCTION (1 GEARING

There are two other types of mainpropulsion, double-reduction gearing in usethearticulated gearing and the nested gearing.

Articulated Gearing

The ARTICULATED GEARING, shown infigure 7-18,. has more bearings and occupiesmore longitudinal space in a ship than the nestedor locked-train type reduction gearing, shown infigure 7-1q.- This type is seldom used in theNavy; it is nth * on combatant ships.

Nested Gearing

The nested gearing rig. 7-19) is the simplestof all double-reduction gears. It uses eminimum

EXTERNAL SPUR GEAR

FIREMAN

2NDREDUCTIONPINION

1ST REDUCTION PINION

1ST

REDUCTION GEAR

MAIN GEAR

47.28Figure 7-18.Articulated type of double gearing.

2ND REDUCTIONPINION

1ST 'REDUCTIONPINION

1ST

REDUCTIONGE AR

2N D

REDUCTION ,

PINION

2ND REDUCTIONPINION

amok: IT1ST

REDUCTIONINION

1ST

REDUCTIONGE AR

/NDREDUCTIONPINION

2ND REDUCTIONOR MAIN GEAR

47.29Figure 7-19.Nested type of double reduction gearing.

number of bearings aril flexible couplings. Thenested gearing type is used on most auxiliaryships; it is NOT used on combatant ships.

The ge ritrg used in shipboard pumps andauxiliary IT achinery is not as complicated as the

82

88

DOUBLE HELICAL GEAR

INTERNAL SPUR GEAR

WORM GEAR

SINGLE HELICAL GEAR

Dt\IEL GEAR

5.22Figure 7-20.Types of gears found in shipboard

machinery.

reduction gearing used fOr main 'provision.iigured 7-20 Illustrates common forms of gearsused in shipboard machinery. Probably one ofthe simplest types of reduction gearing is theworm gear shown in figure 7-20.

Worm Gear

Watpj gears are used to transmit motionbetween shafts which. are at right angles to eachother. The worm gear consists of a cylinder withone or more threads (sing, doUble, triple) cut on

Chapter 7STEAM TURBINES AND REDUCTION GEARS

the outside like a screw. The worm wheel is agear with teeth cut on the outside rim to meshwith the threads on the worm.

The worm gearing speeds reduction. Acomplete turn of the worm turns the wheelahead the distance of one tooth on the wheel. Adouble thread worm will revolve the gear twiceas fast as a single thread worm.

REDUCTIONGEAR CONSTRUCTION

unit,The gears in a main reduction gear u sue.has the main gears,and the pinion gears, must becapable of transmitting tremendous power loads.The pinibn gear is the smaller of two meshinggears and is usedjnainly for decreasing speedand increasing power,. Since even a very slightunevenness of tooth contour and spacing willcause the gears to operate noisily; or even fail,special precautions are taken

hemanufacture the

gears to exact dimensions. The gear§ are cut in aroom maintained at constant teniperature andhumidity to eliminate expansion, contraction,and oxidation of the metal.

Almost all pinion gears in mite reductiongearing are machined completely of speciallyheat-treated, nickel-steel forgings. Generally, thegear wheels are of built-up construction with theteeth cut in forged steel bands which are weldedto ste webs.bs. The first reduction gears aregeneral! welded on their respective shafts. Thebull gear is usually pressed on the shaftagainst alocating shaft shoulder and is Secured by one or

ore keys and a locking nit mechanism (fig.7-21).

Gear casings can be divided into three majorparts:

. . ,

1)`gear,

lower part (base section) supportstihe bull gear, main thrust bearing, and thehigh-speed parts of the reduction gear. Thelowerosection al-so serves as the sump or. storagetank for the lubricating oil in the system.

2) The intermediate section of the casingsupports the bearing housing for theintermediate speed pinions and gears as well asthe high speed pinions. 1:'

3) The uppelipart of the gear casing is themain cover which is divided into two sectionswith inspection ports so located that the teethof any pinion or gear can be examined withoutremoving the main cover sections. Theinspection ports are covered with easily openedhinged covers.

Reduction gearing for pumps and otherauxiliary machinery is constructed , slightlydifferently than the main reduction gearing justdiscussed. In the ship's service generator, thepinion is forged together with the shaft as onewhole part. One end 'of the pinion shaft isflanged and bolted rigidly to the- turbine shaft.The gear wheel is pressed and keyed onto theshaft.. .

In main circulating pumps the on is asolid forging, while the gear it cons 'd bywelding a forged hub and a forged rim ogether.The gear hub is bolted to a plate which is keyedto the gear shaft,.) 4

The reddaicon gear of a turbine-drivencondensate pump, shown in figure 7-22, which isa worm shaft and a worm wheel, reduces theturbine spe of approximately 5500 rpm todpump spe of approximately 1100 rpm. Theworm is cut in a solid, low-carbon, nickel-steel

ft. forging. The worm wheel is a solid nickel-bronzecasting wliklf pressed onto a forged steelshaft. The gear casing is of cast steel to formrigid suppoit for the rotating e ents. It is splithorizontally for easy assembl or disigsembly.

LOCKINGNUT

WHEEL

KEY SLOT

KEY SHAFT

8983

4

Figure 7-21.--Key and !odd nut.13 .3'0

rs

0'

FIREMAN

WORM a SPURREDUCTION GEAR

TURBINECASING

PUMP SHAFT

47.38Figure 7-22.Main condensate pump roduction.bearing.

LUBRICATION

All moving ires receive a steadyand adequate supply of oil of proper quality atthe correct temperature. Impurities and foreignmatter must be removed from the lubricationsystem and a reserve supply of good clean oilmust be maintained.

To understand the principles of lubrication,you should know the purposes of a lubricant.Lubricants reduce friction between movingparts. Frictiori is the resistance to -motionbetween the two bodies in contact. When thisfrictional resistance is overcome, and motiontakes place, heat is generated. There are three

.kinds of friction: .1. SLIDIkG FRICTIONbetween two

solid objects whose outer surfaces slide overeach other.

2. ROLLING FRICTIONbetween twosolid objects, one (or both) of which is rollingon. the other.

3. FLUID FRICTIONbetween the,molecules or particles of a fluid, or between twofilms of fluid.

Since liquid lubricants can be -readilycirculated, they are used universally for internallubrication. Lubkicating oils are mineral oilsobtained petroleum. In theory, eluidlubrication is b ed on the alUal separation ofthe surfaces so that no metal-to-metal contactoccurs. As long as an oil film remains unbroken,sliding or rolling friction is replaced by the fluidfriction (internal friction) of the lubricant itself.Under such ideal conditions, friction and wearare held to a minimum.

41,

Purpose of Lubrication-ccts

The primary purpose of lubricating oil andgrease is to SUBSTITUTE FLUID FRICTIONFOR EITHER SLIDING OR ROLLINGFRICTION. This means that a lubricant ofsufficient quantity and consistency must beprovided to keep the moving metal parts (ofbearing, lining, and journal, for example) fromcontacting each other. The remaining fluidfriction, within the-lubricant itself, is far lessthan that which would otherwise occur betweenthe solid objects, but it also generates heatwhich must be removed:

The secondary (but highly important)purpose of a lubricant is that of ABSORBINGAND REMOVING THE HEAT which isgenerated by the fluid fti on as well as the heatwhich, in steam turbine conducted along theshafting from the steam-h d rotors. Removalof this heat by the lube oil prevents seriousdamage to the machinery parts and makes itnecessary to have the oil repeatedly cooled as it

`circulates about the mechanisms

In general, BOTH FRICTION ANDOPERATING TEMPERATURES in bearingsincrease with a g.vater unit bearing pressurei,with thinner films b.f. the lubricant, if below adefinite minimum; with a high velocity ofrubbing or rotation-of the journal; and with a

84

90

Chapter 7STEAM TURBINES AND REDUCTION GEARS

BEARING

JOURNAL

OIL FILM

47.78Figure 7-23.The oil film ceparates the rotating,

shaft from the bearing.

higher viscosity of the lubricant. (Viscosityrefers to the flowing qualities of a liquid. Waterand gasoline or liquids which flow freely, havea low viscosity. Cold molasses and honey do notflow freely; therefore, they have a highviscosity.)

Bearing Lubrication

Most of the moving parts of a machine aresupported in bearings that permit them to rotatefreely. Lubrication consists of supplying thesebearings with oil. The oil forms a film on thesurfaces of the shaft and the bearing, and keepsthem separated (fig. 7-23). An oil must beselected that has enough body to keep the metalsurfaces from touching each ther during ALLoperating conditions.

Bearings that carry asometimes lubricated Ailith grare equipped with standardfittings like those on an autmust be kept filled at all ti

heavy load arese. These bearingsease cups or zericmobile. The cupses. The shafts of

85

some rotary water pumps are lubricated with asmall amount of water that leads through thebearings and moisten the packing.

Lubricating Systems

Each turbine is provided with a lubricatingsystem that supplies oil under pressure to tbearings. The system consists a sump orreservoir for storing the oil, an oil pump, astrainer, a cooler, temperature and pressuregages, and the necessary piping to carry the oilto the bearings and back to the sump. Thelocation and arrangement of these parts varywith each make and type of turbine.

The lube oil pump is generally a gear-typepump. A definite pressure is maintained in theoil feed lines. A pressure relief valve allowsexcess oil to recirculate back td the suction sideof pump.

Quite often dual strainers are connected inthe line so that the system can operate on onestrainer while the other one is being cleaned.The tube-in-shell type of cooler is generally usedwith sea water, zirculating through the tubes andthe oil flowing around them. The temperature ofthe oil is controlled by adjusting the valve thatregulates the amount of sea water flowingthrough the tubes.

Oil must circulate through the turbinebearingsoat the prescribed pressure and withincertain 'temperature limits. A pressure gageinstalled in the feed and a. thermometerinstalled in the return line indicate whether theoil system is functioning properly.Thermometers are often installed in the bearingsto serve as a warning against overheating. Ifthere is a decided drop in oil pressure, theengine should be shut down immediately; evena moderate rise in the oil temperature should beinvestigated. An oil-level float gage indicates theamount of oil in the sump.

Lubricating Oiland Greases

Many different kinds of lubricating materialsare in use, each of them filling the requirementsof a particular set of conMons. Animal and

OP

FIREMAN

vegetable oils and even water have goodlubricating qualities, but they cannot withstandhigh temperatures. Mineral oils, Aimilar to theails used in an automobile engin?", are the besttype of lubricant for modern machineryoperating at high speeds and high temperatures.Some heavy-duty bearings are lubricated withgrease in about the same way that the springshackles and steering gear of your car aregreased.

Mineral lubricating oils are derived fromcrude oil in the same process which producesgasoline, kerosene, and fuel oil. They varyaccording to the type of crude oil and therefining methods used. The same type of oil isusually made in several grades or weights. Thesegrades correspond to the different weights of oilfor an automobile varying from light to heavy.

Oils used in the Navy are divided into 9classes, or series, depending on their use. Eachtype of oil has a symbol number that indicatesits class and viscosity. For example, symbol2190 oil is a number 2 class of oil with aviscosity of 190 Saybolt Seconds Universal. Theviscosity number represents the time in secondsthat is required for 60 cubic centimeters (dc) ofthe oil, at a temperature of 130° F, to flowthrough a standard size opening in -a Sayboltviscosimeter (fig. 7-24).

A 2190TEP oil is used for all propulsionturbines and reduction gears. The letters TEPindicate that the oil has been treated to give itwater-protecting and corrosion-resistingproperties, and extra load carrying capacity.This oil is also used in the turbines that drive thevariou% kinds of pumps an blowers, exceptthose pumps that are driven through a wormgear which use a Navy symbol 3080 oil.

Lubricating greases are mixtures of soap andlubricating oil. Fillers, such as graphite, are alsoadded to some greases to make the\ grease moreeffective for certain lubrication requirements. .

The soaps used on the common SOAP ANDOIL GREASES are chemical compounds formedby fats or fatty acids' reacting with variousalkaline materials such as lime, soda, aluminum,zinc') barium, lithiumjead, and potassium.

HEATING OILVESSEL

WASHERS

".NUTORK

38.214Figure 7- 24. Details of the viscosimster tube.

L.)The common SODA SOAP GREASES

used for applications where no water is prese tand where operating temperatures approach 20F. The common LIME SOAP GREASES do n tabsorb moisture or emulsify as readily as thesoda soap greases, but have lower melting points.They are us-ed as general purpose greases forlight load applications at ordinary operating,temperatures.' These two types of greases willsatisfactorily lubricate the majority ofmachinery.

Certain lubricating greases containVitives.These SPECIAL ADDITIVE AREA S areidentified by the additn. For example, LEADOLEATE SOAP GREASES are used for certainbearing surfaces which are so heavily loaded that

86

- 92 e

1,

Chapter 7STEAM TURBINES AND REDUCTION GEARS

ordinary grease will not maintain a film toprevent contact of the rubbing surfaces.EXTREME PRESSURE GREASES alsoincorporate special additive agents to providenecessary film strength.

OXIDATION INHIBITOR GREASES havean additive incorporated to ensure betterstability at high temperatures and to preventrusting under these conditions. In GRAPHITEGREASES, the added graphite acts as a mildabrasive to help smooth roughened surfaces, andacts as a Her to smooth over unequal surfacespots. It also substitutes its own low friction forthat of the metal it covers; this is especiallyimportant where a bearing is exposed totemperatures so high that ordinary grease or oilwould break' dOwn. Except for such hightemperatures, .`gr4hite grease should not be usedin bearings which are in first-class condition.

-Each of thscs several types of greases issupplied in three grades: soft, medium, andhard. SOFT GRADES are used at high speedunder ight pressure; the MEDIUM GRADES areused at medium speeds under medium pressure;

4,

93

and the HARD GRADES are used at slow speedsunder heavy pressure.

Standard Navy Lubrication°

AlWays be sure that you are using thespecified lubricant for the individual machinery)part, unit, or system you are responsiblefor operating or maintaining.

Most ships make up LUBRICATINGCHARTS for quick reference on thisinformation. These charts generally Contain aline diagram of the unit or system, point oflubrication, symbol of lubricant, quantity, Indinterval of supplyalong with applicable generalinstructions, operating hints, and possiblecasualties. The charts are generally posted in 1(--machinery compartments.

The manufacturer's technical manual foreach- unit of machinery is the basic reference forthe correct lube oil, if no lubrication chart(based on manufacturer's instructions) isavailable. In addition, the TABLE OFRECOMMENDED OILS can be found in chapter9450 of NavShips Technical Manual

87 .

CHAPTER 6

AUXILIARY' MACHINERY AND EQUIPMENT

steam-jet refrigeration system and the vaporcompression cycle refrigeration system. Thesteam-jet system is used on some naval ships forair conditioning and on some merchant ships forlarge area, moderate temperature refrigeration.The steam-jet plant (fig. 8-1) consists of a flashtank, a booster ejecta, a condenser,, air ejectors,and the necessary pumps. and piping. 'The flashtank (sometimes called the, evaporator) ismaintained unde /exceptionally high vacuum bya steam-jet boo ter ejector as water is sprayedinto the flash tank, part of each drop flashesinto vapor and thereby cools the unvaporizedportion of each drop to approximately 50°F, orlower depending on t.Itcapacity of the unit.The cooled water theo the bottom of thesh , then pumped to the cooling coils andr rned to the flash tank at a temperature ofa proximately 55°F.

In addition to the propiiIiittiLmachinery andequipment, you will become acquainted withother types of machinery, such as refrigerationequipment, air conditioning equipment anddistilling plants. You will also becomeacquainted with the steering gear, the anchorwindlass and capstan, lube oil purifier , undryeotOpment, galley equipmeht, air compre rs,orafies, elevators, and 'winches. The informationprovided in this chapter will be general innature; primarily, we shall discuss the locationand the function of the auxiliary machinery andequipment mentioned above.

° REFRIGERATION EQUIPM

There are two basic types of mechanicalrefrigeration systems used in the Navy, the

J

VENT

AIR. EJECTORS

-0- STEAM LINES

1STSTAGE

COOLING

WATER

AFTER

CONDENSER

ORA N TOSHIP'S SYSTEM

..11 r 1213" V U 1.,

BOOSTER EJECTOR

AUTOMATIC VALVE ANDSTEAM CONTROLS

STEAM

FLASH TANK

LINE

COOLINGSALT WATER

k

2Y' VACUUM

SPRAY PIPES

INTER

CONDENSER

DRAINCONDENSER

..,e,...-4- 4...... .. **_,. ""_ ./ *".%. "L >,,

*> k ki AAP)WATERCONTROLLER

LdvEL

CONDENSER

PUMP..

=4:CHILLEDWATER ----r="

PUMP

TO

4

CONDENSATE TO RECIRCULATINGLINE AND SHIP'S DRAIN SYSTEM

Figure 8-9. Steam -jet refrigeration systeip.

88

-94

CHU.LED ATER SYSTEM

47.89

Chapter 8 AUXILIARY MACHINERY AND EQUIPMENT

EVAPORATORCOMPRESSOR

123 VAPOR

REIRIORANT

.1=3 MODREFRIGRANT

+1ST FLOW

CORADiSER

RECEIVER

SEA

WATER

47.90Figure 8-2.Vapor compression (R -12) cycle

refrigeration.

,- The vapor compression cycle refrigerationsys m (fig. 8-2) is most commonly used onnaval ships in various applications, such asrefrigerated6hip's stores, refrigerated cargo, andunitary (self-contained) refrigeration (as ship'sservice store equipment).

Ship's stores spaces are refrigerated for thepreservation of food supplies. The insulatedcompartments for cold storage spaces are thewalk-in type. The equipment selected to coolthese spaces is designed to maintain certaintemperatures: for ships designed before 1950,the meat room at 15°F, fruit and vegetablerooms at 40°F, butter and egg rooms at 32°F;and for ships designed since 1950, the freezeroom at 0°F and the chill room, at 33°F.

Auxiliary ships have refrigerated cargospaces for stowage of perishable food that isintended for the forces afloat and for advancedbases. Approximately 30 to 60 percent of therefrigerated cargo space is maintained at 0°F (at-5°F on the latest designed ships). Theremainder of the refrigerated area is maintainedat 33°F to 35°F.

Unitary refrigeration systems are of twotypesremote and self-contained. The remotetype is a complete unit except that the source ofrefrigeration is lOcated separately and is notcontained within the unit cabinet. Equipment ofthiS,type includes soda fountains and ice creamhardening machines.

89

-

The self-contained units, which have therefriirration source within the unit cabinet,inchlae d king water coolers, refrigerators, andfrozen od cabinets.

Other refrigeration equipment includes twotypes of ice-making machines. One type is aself-contained unit which makes ice cubes: Theother is a tank-type which m*.rs large slabs ofice. The tank-type ice mac T. is normallylocated in a separate machinery room which isidentified as the ice machine room. This type isinstalled on auxiliary ships such as tenders andrepair ships.

AIR CONDITIONINGEQUIPMENT

Air conditioning is installed on naval shipsfor Certain spaces where personnel efficiency,health, safety, or operation of equipment maybe endangered by high temperatures or highhumidity.

Some of the spaces that might be airconditioned include the radio and radar controlspaces, sick-pay areas; and living and berthingspaces. The radio and radar control spaces areusually air conditioned because& the high heatgiven off by the equipment. This heat, especiallyin combination with high humidity, lobedangerdus to the operator and the equip Alt.Air conditioned sick-bay areas haVe provenadvantageous" in that they help to speedrecovery. The living and berthing spaces areoften air conditioned, both to provide comfortfor the crew and to increase personnelefficiency.

There are two basic types of-air conditioningequipment used aboard ship. One type useschilled water for the cooling medium; the otheruses refrigerant R-12 to carry away the heat.Most of the air conditioning equipment aboardNavy ships uses the.refrigeration equipment forthe removal of heat from the circulating wateror refrigerant. *Heat is removed by the coolingcoils of the refrigeration equipment. There arealso some (smaller selfzcontained units usedaboard ship similar to the window type used inhomes.

rz

O

FIREMAN

FIRST-EFFECTSEPARATOR

VAPOR FEEDHEATER

FIRST-EFFECTTUBES

'FIRST-EFFECTDRAIN REGULATOR DIVISION PLATE

SECOND-EFFECTSEPARATOR

DISTILLINGCONDENSER

SECOND-EFFECTTUBES

Figure 8-3.Soloshell doubfa-effect distilling plant.

Steam operated distilling plants re classifiedas coil, submerged, tube, vertical basket, andflash types. The coil type is found on a resolder auxiliaries, while the submerged tube typeis found on most older sh,ipsahe vertical basket -and flash types are newei'designs and have beeninstalled on some combatant ships constructedin the last 15 years. Some submerged tube typeswere also installed during thkperied.

In the vertical basket type low-pressuresteam flows into a corrugated basket that issurrounded by sea water. Sere the steam giveS'up its heat to boil the .sea; water and is thencondensed. The fresh water vapor from theboiling sea water is condensed and then removedas distillate (fresh water).

In ,the flash` type, preheated feed water isdischarged into a vacuum chamber where a

Aim of the water is vaporized (flashes intoste ). The remaining water passes into aecond flash chamber where further vaporization

DISTILLING PLANTS

The two basic types of distilling- plantsq igialled aboard naval ships are the vapor

compress '- distilling plant and e 'beamdis v. plant. The main difference bet n thetwo ty es of distilling plants is in the ethodused t e apply heat to the sea water., In the vaporoompre on plant, the source of heat isobtained om electrical energy.

The vapor compression type distilling plantwas first developed primarily for -submarine,service, where the absence of steam made itnecessary to supply anotfier form of heat

,nergy. However,- on newer type submarines,this type plant is currently u ed for back-uponly. It is also used on older, sm iesel-driven

cesurface craft where the daily dem d for freshwar does not exceed 4,000 gallons per day(gpct). The vapor compression consists of threemain componentsevaporator, compresior,heat exchanger. .

FLASHCHAMBER

BRINE PUMPSUCTION

SECOND-EFFECTDRAIN REGULATOR

47.117

Chapter tj--UXILIARY MACHINERY AND EQUIPMENT

takes ace. Any number of flash chambers,where liporization takes place, can be installed.Each sta e has a condenser in which the freshwater vapor is condensed.

There are three basic typos dfsubmerged -tube type distilling plants: soloshelldouble-effect (fig. 8-3), the Viple-effect, and thetwo-shell double- effect. The principal differencebetween the triple-effect plant and the two-shelldouble-effedt plant is the number of stages ofevaporation. In the double-effect plantevaporation takes place in-two stages, while inthe triple-effect plant.evaporation takes place inthree stages.

The most commonly used 20,000 gpdtwo-shell double-effect plant is built with twohotizontal 'cylinder evaporator shells mountedparallel to each other. The triple-effect distillingplant is similar to the two-shell double-effectplant except that the triple-effect plant has anintermediate evaporating stage. A standardtriple-effect, 20,000 gpd plant is illustrated infigure .84.

Almbst all low-pressure distilling platsand including the 12,000 gpd capacity plant

up

1

errE

AUXILIARYSTEAM INLET

FEED CHEAT

are of the soloshell double-effect type. This typoconsists of a single shell that has a verticalpartition which divides the shell into twoevaporator shells.

One type of 20,000 gpd caOcity, soloshelldooiote-effect plant is installed on some of theolder ships. Where it is necessary to furnish40,000 gpd, two such plants are installed. Someolder destroyers are equipped with two soloshellcvr orator plantsone, located in the forwardmien oom with a capacity of approximately12,000 gpd; the other, located in the aftengineroom, with a capacity of approximately4,000 gpd.

STEERING GEARS

There are two basic types of steeringmechanisms in use in the Navy. One is theelectromechanical steering gear, used extensivelyon small noncombatant ships. The other, andmost common, type is the electrohydraulicsteering gear. In the electromechanical steeringgear, an electric motor is the prime mover. Theelectric motor receives a signal from the bridge

2nd EFEECT FEED HEATER

AIR EJECTOR"VAPOR OUCONDENSER

CONDENSATECOOLER

DRAIN CONNECTIONS2nd 'OHO

BRINE P SUCTION

3rd EFFECT

47.118.1Figuro 04.-20,000 gpd triplo-affact distilling plant.

91

97

FIREMAN

and, through shafting and a gear arrangement,moves the rudder.

In the electrohydraulic steering gear,movement of the rudder is obtained fromhydraulic rams operating in cylinders that areconnected to variable delivery pumps.Development of this type was prompted by thelarge electrical power requirement necessary tosteer ships of large displacement and highspeeds.

The electrohydraulic steering gear providessame udistinct advantages over theelectromechanical steering gear:

I. Little friction between moving parts2. Immediate responses to movement of

the steering wheel3. Requires small deck space and head

room4. Savings in weight5. Flexibility and dependability.

There are various types of electrohydraulicsteering gears in use, but their operating

YOKE

principles are basically the same. Some ships.have double hydraulic rams and cylindersmounted fore and aft, as shown in figure 8-5,while other ships employ a double cylinder,single-ram, mounted athwartships. A typicalsingle-ram electrohydraulic steering gear isillustrated in figure 8-6.

Emergency steering gear is provided on allcombatant and auxiliary naval ships that haveelectrohydraulic steering gear. Generally, largecombatant ships have a duplicate hydraulicsteering gear for emergency use. On other shipsthe emergency gear consists of a hand-operatedhydraulic pump.

ANCHOR WIND LASSAND CAPSTAN

A windlass is a piece of deck machinery usedprimarily for paying-out and heaving-in ananchor chain. A wildcat (drum), fitted withwhelps to engage the anchor chain may bemounted eit'her vertically or horizontally at theend of the windlass shaft. (A whelp any one of

TOLE

PUMP

CYLINDER

CYLINOEIOLE

MOT

SHAFTS

SIX-WAY PUMP 0

TRANSFER COC TR" 'NG!AXES

RuODERCTLINOEN

ELECTRIC LEADSFROM STEERING STAND

N.{

41 014111 66666

RACK ANDPINION

RUNNINGPUMP

SELL SYNCHRONOUSnEcEIYEH

B

PLANETARYDIFFERENTIAL GEAR

NISUPPLYRETURN

4

Figure 8-5.Diagrammatic arrangement of a double-rem electrohydraulic steering gear.

92

98.7

47.139X

.1

Chapter 8kUIC MARY MACHINERY AND EQUIPMENT

the ribs or ridges on the drum of a windlass. Itlooks much likaD the sprocket wheel o a chainfall.)

General requirements of the anchor windlassare that it must be simple, rugged, and reliable.It must be capable of reversal and have suitablebrakes.

There *e three 'general types ofpower-driven anchor windlasses:electrohydraulic, electric, and steam.Hand-operated windlasses are used on smallships where the weight of the anchor gear can behandled without excessive effort by operatingpersonnel.

Tjae electrohydraulic anchor windlasses areadvantageous where the load varies through awide range because of the amount of anchorchain payed out, the force of the wind, thestrength of the tide, and the type of bottom inwhich the anchor is set. Figure 8-7 illustrates atypical electrohydraulic anchor windlassarrangement.

AUTOMATIC BYPASS

PORTCvlOADIR

Some) older naval ships are equipped with ageared windlass driven by a steam engine or anelectric motor. Some of the new smallercombatant ships such as destroyers anddestroyer escorts are equipped with the electricmotor type. Figure 8-8 I)lustrates an electricwindlass for a modern dest oyer.

A capstan is a spool-shaped, verticallyMounted drum used for heaving-in on heavymooring lines. Figure 8-9 shows a vertical shaftanchor windlass capstan which is normal topsideequipment on a destroyer. The capstan is acomponent part -of the anchor windlass, asshown in figure 8-7 and figure 8-8.

LUBE OIL PURIFIERS

Purifiers, normally located in theengineroom, are used to free contaminated lubeoil or diesel oil of water, sediment, and the otherimpurities. The purifiers used in the) Navyoperate on the principle of centrifugal force;

STEEIONO WHEELON AFTER COO( HOUSE

(f*I0PORT

TRANSMITTER UNIT

nileiTcs",ELECTRIC CONTROLI

SYSTEM

TRANSMITTER

POST OR SPED CARLTRANSFER SWITCH

CROSSHEAD

PLUNGER(RAW

RICOMINDER

CRANK FOR HANG OPERATIONOF PORT PUMP

1,RUNPONG PUMP I,

oi,?tal

AFTERECK

POLL OTUPINAPT

UNIVERSAL JOINT

AUTOMATIC RFPAIS

sum v

Aram,

MU PUMP

STARBOARD

IDLE ELECTRICMOTOR

STARDOARDCARLE

TRANSFER SWITCH TRANSMITSCURRENT THROUGH EITHERCARLE OR TRANSMITTERTO RECEIVER AS WOW

TRICK WHEEL FORHAND CONTROL

WORM WORMWHEEL

SPIRAL GEARS

Figure 8-6.Diagram of typical single-ram electrohydraulic steering gear system.

-- 9 9

27.83X

*\

FIREMAN

CONTROL STANDINDICATOR

CAPSTAM 4EAOWILOCAT

BRAKE OANONANO OPERATED

CHAIN PIPE

WEATHER OECK

GAGE GLASSEXPANSIONTANK

OECK CONTROLFOR TILTING BOXOR FLOATING RING

AIR ESCAPEHYORAULIC COCKS

PRESSUREGAGE

MOICATORHANO WHEEL FORLOCAL CONTROL

RELIEF VALVE3 WA' COCK

INOENT ANO SPRINGLOA0E0 PAWL

LOCKINGHE AO

REOUCTIONGEARS

MOTORH YOR AUL ICMOTOR

B-ENO

TO STVO WINOLASSSAME AS PORT

PINION GEARA -ENO

IL

SECTION THROUGH PORT WINOLASS

DECK

MAIN OECK

77...

11

VARIABLESTROKE PUMPS COUPLING

Figura 8-7.Typical olectrohydraulic anchor windlass arrangement.

iceNr

7:71.11.4.4

12-i"rFRICTION DRAKE

LOCKING IIANDWHEEL

DRIVE

MOTOR

lbw TIIIIPIIIIIIIIIIIIIII-;`44. ;I I rtgl,lilw

fp

MOTOR OPERATED BRAKE

MAGNETICDRAKE

47.143X

that is, a bowl or hollow cylinder is revolved athigli speeds while contaminated oil is passedthrough it. This procedure separates theimpurities from the oil. There are two types ofpurifiers, the tubular type and the disk types

The hollow cylinder or tubular type isrelatively small in diameter and is operated athigh speed. The cylinder is fitted with athree-wing device that keeps the liquid rotating

) at the speed of the bowl without slippage.Figure 8-10 shows the tubular type purifier.

The disk type purifier has a bowl of largerdiametei, which is fitted with a series of disksthat separate the liquid into thin layers. Ase nal view of a disk type purifier is shown infigu re 8-1 1.

AIR COMPRESSORS

There are many uses for compressed airaboard ship and it would be difficult to mention

Figure 8-8.Electric windlass. 3.224k all of them. Some of the more common uses

94

10

Chapter 8AUXILIARY MACHINERY AND EQUIPMENT

include: operating pneumatic tools; ejecting gasfrom ship's guns; starting diesel engines; chargingand firing torpedoes; operating gunco un terrecoil mechanisms; and operatingautomatic combustion control systems.Compressed air is supplied to the varioussigNrns by, high-pressure, medium-pressure, orlow-pressure air compressors, as appropriate.Reducing valves reduce a higher pressure to alower pressure for a specific system.

Air compressors are classified in a number ofways. A compressor may be single-acting(compression on one end of the stroke)(,double-acting (compression on each end of thestroke); single-stage (one cylinder); multistage(more than one cylinder); and the compressordesign may be such .that the pistons operatehorizontally, vertically, or at an angle.Compressors are also classified according to thetype of compressing element; the source ofdriving power; the method by which the drivingunit is connected to the compressor; and 'thepressure that is developed.

ra

Air compressors may be of the centrifugal,rotary, or reciprocating type. The type used isdetermined by the volume and pressure of airdesired. Most of the compressors used in theNavy are of the reciprocating type.

Compressors are driven by electric motors,internal combustion engines, steam turbines, orreciprocating steam engines. The air compressorsused most in the Navy are driven by electricmotors.

Low-pressure compressors are those whichhave a discharge pressure of 150 psi or less.Medium-pressure compressors are those whichhave a discharge pressure of 151 psi to 1000 psi.Compressors which have a discharge pressureabove 1000 psi are classified as high-pressure aircompressors.

CRANES

Cranes are designed to raise a load, lower it,and move it in horizontal directions. You will

r`1

I

.-4

flo

941Airaini-

47.146Figure 8-9.Vertical shaft anchor windlass capstan head.

95

FIREMAN

IBELT GUARD

I MOTOR PULLEY I

COUPLING NUT

PURIFIEDOIL OUTLET

I FUNNEL COVER

LOWER COVER I

Figure 8-10.Tubular type centrifugal purifier (Sharpies).

find cranes installed on carriers, cruisers, andauxiliaries. Cranes are used for handlingairplanes, boats, bombs, torpedoes, mines, sweepgear, missiles, trucks and stores. Somesubmarines are also equipped with cranes forhandling missiles.

In general, cranes may be electrically-driverf,engine-driven, or hand-driven. Cranesconstructed for very heavy loads (lifting heavyaircraft, boats, or torpedoes) are usuallyelectrohydraulic.

9,6

102

47.86

Detailed information concerning shipboardcranes can be obtained from applicablemanufacturers' technical manuals.

ELEVATORS

Many avy ships are equipped with elevatorswhich are used to handle bombs, airplanes,freight, torpedoes, and ammunition. Shipboardelevators are divided into two general _di

classeselectrohydraulic andsplectromechanical.

et 4

Chapter 8AUXILIARY MACHINERY AND EQUIPMENT,

ELECTROHYDRAULIC ELEVATORS aredivided into two general typesthe directplunger lift and the plunger-actuated cable lift.

The platform of the DIRECT PLUNGERLIFT ELEVATOR is raised or lowered by oneor more hydraulic rams, which are located underthe platform. During the hoisting of a platform,hydraulic oil is pumped into the ram from ahigh-pressure tank (approximately 950 psi).Lowering of the platform is performed bydischarging the oil from the rams into alow- pressure t ank, which is under anapproximate pressure of 230 psi.

Pressure is maintained in the high-pressuretank' by two hydraulic pumps (variable stroke),which take suction from the low-pressure tanks.

COVER CLAMP HOOK

LARGE SPRING

COVER CLAMP SPRING

LONG COVER CLAMP

INLET ARM SEALRING

SPRING SIDE

BALL CHECK SPRING

BALL CHECK VALVE

VALVE STOP SCREW

Special control valves, located in the pressureand exhaust lines, regulate elevator speeds byvarying the amount of hydraulic oil admitted to,or discharged from, the rams. Mechanical locksallow the platform to be locked and held inposition at deck level. Automatic quick-closingvalves in the oil line prevent an unrestricted fallof the elevator.

The platform of the PLUNGER-ACTUATED CABLE LIFT ELEVATOR israised by wire rope fastened to the platform ateither two or four joints. Most hydraulicairplane elevators are of this type. The wireropes in an airplane elevator are operatedthrough a series of pulleys by a horizontalhydraulic ram located below the hangar deck.

INLET ARM

REGULATING TUBE

COVER TOP

COVER TOP SCREW

COVER CLAMP NUT

FRAME COVER

HOPPER

SHORT COVERCLAMP

SEAL RING

BRAKE

BOWLCLUTCH BLOCKSPACER

FRICTION RING

WORM WHEEL

FRICTION HUB

OIL FILLER CA

Figure 8-11.Dish type centrifugal purifiers.

97

103

STUD

TOP BEARING

FRAME .

BOWL SPINDLE

BOTTOM SCREW

47.83

FIREMAN

Special safety devices engate the" guide rails ofthe elevato , stop the fall, and hold theplatform IA en one group of wire ropes fails.

ELE ROMECHANICAL ELEVATORS areused for freight, bombs, and stores. In elevatorsof this type, the platform is raised and loweredby one or more wire ropes which pass overpulleys and wind or unwind on hoisting drums.Hoisting drums are driven through a reductiongear unit by an electric motor. An electric brakestops and holds the platform. The motor hastwo speeds (full speed and low, or one-sixthspeed). Control arrangements allow the elevator

GYPSY

SPEED D OILCONTROL BATH

to start and run on high speed. Low speed isused for automatic deceleration as the elevatorapproaches the selected level. The platformtravels on two or four guides. Hand-operated orpower-operated lock bars, equipped withelectrical interlocks, hold the platform in thestowed position or accurately hold the platformwhen on- or off-loading tracks are used.

WINCHES

A winch is a piece of deek machinery that ,

has a drum or drums on a horizontal shaft for

DRUM REDUCTION ROPE CLUTCHGEAR GEARING GUARD LEVER

BEDPLATE DRUMDRUM

DRUMBRAKE CLUTCH .

DRIVE DRUMMOTOR BRAKE

LEVER

ELECTRICBRAKE

80.149Figure 8-12.Units of an electromechanical winch.

104

Chapter 8AUXILIARO MACHINERY AND EQUIPMENT

handling loads with wire rope. In addition, cargowinches may be equipped with one or two gypsyheads fitted for handling manila rope. Figure8- 1 7 illustra .s the units of an electromechanicalwinch.

Winches are of the steam, electromechanical,or electrohydriAc types. Winches handle wirerope used wail equipment such as booms anddavits for handling boats and cargo; for fuelingand replenishment at sea; and for miscellaneousoperations when the handling of rope undertension is required.

Steam winches are normally installed onsuch, ships as tankers, where use in the vicinityof flammable materials is required. Other oldertype auxiliary ships, which have direct-currentpower supplies, use electromechanical winches

)where d-c motors provide the desired speedcontrol of the winch drum or gypsy head. Sincenewer auxiliary ships and all combatant ships donot have direct-current power supplies, they areequipped with electrohydraulic winches. In anelectrohydraulic winch, the stroke adjustment ofthe hydraulic pump provides the desired speedcontrol of the drum and the gypsy head.

LAUNDRY EQUIPMENT

Prior to 1914, personnel aboard naval shipswashe d'. their laundry by hand. Their equiptventconsisted of a bucket, soap, and water. Todaymost all naval ships are equipped with laundryfacilities. Carriers, tenders, and repair ships alsohave drycleaning equipment.

The laundry equipment in a modem ship'slaundry consists 'of washer-extractorconalt*tions, dryers, various types of ironingand `pressing equipment, plus numerousmiscellaneous items Such as laundry markingmachines.

GALLEY EQUIPMENT

The food preparation and service equipmentlocated in the galley and messing spaces aboardnaval ships is designed for quantity food service.

Galley equipment is used for the cookingand preparation of food for use in the-generalmess. This equipment consists of ranges, ovens,griddles, deep-fat fryers, mixing machines, meatslicing machine, cube steak machine, coffeeurns, toasters, .steam jacketed kettles, steamtables, scales, refrigerators, cooking utensils, anddishwashing machine. Other equipment that areused specifically for vegetable preparation arethe machine-driven potato peelers, food cutters,and the french-fry cutters. _Normally, the latterthree y pieces of equipment are located in avegetable preparation room.

On large ships such as carriers, tenders, andrepair ships, there is also a meat cutting room(butcher shop) where meats, fish, and poultry

'Arel, prepared for cooking. The equipmentnqrAally found in this area consists ofmeat-cutting blocks, meat-grinding machines,power-driven meat-cutting bandsaw, slicingmachines, knives and other meat cutting tools,and hooks for hanging meat.

10599

CHAPTER 9

INSTRUMENTS

Measurement, in a very real '''sense, is thelanguage of engineers. The shipboard engineeringplant has many instruments that indicate tooperating personnel conditions existing within apiece of machinery or a system. By properinterpretation of the readings of theinstruments, operating pea nel can determinewhether the machine , or the system, isoperating within the pr- ed range.

Recorded instrument readings are used toensure that the plant is operating properly andalso to determine the operating efficiency of theplant. The instruments provide information forhourly, daily, and weekly entries for stationoperating records and reports. The data entered

/in the records and reports must be accurate sincethe engineer officer studies the records andreports to keep up with the condition of theplant. Remember that accurate data entered onthe records and reports can be obtained only byreading the instruments carefully.

The instruments, indicators, and alarmsdiscussed in this chapter are included not onlybecause of their relative importance in theengineering plant, but also to give you an idea ofthe wide raige and type of instruments,

- indicators, and alarms that are used in theengineering plant aboard a naval ship.

Engineering measuring instruments mayclassified into the following groups:

1. Pressure gages2. Thermomete d pyrometers3. Liquid leve ndica4. Fluid flow ters5. Revolutio nters and indicators.

be

100

108

PRESSURE GAGES

Pressure gages include a variety of Bourdontube gages, bellows and diaphragm gages, andmanometers. The Bourdon tube gages aregenerally used for measuring pressure of 15pounds per square inch (psi) and above. Thebellows and diaphragm gages and manometersare generally used for measuring pressures below15 psi.

BOUkDON TUBE GAGES

The most common Bourdon tube gages usedin the Navy are the (1) simplex, (2) vacuum, (3)compound, and (4) duplex gages. They operateon the principle that pressure'' n 'a curved tubehas a tendency to straighten o t the tube. Thetube is made of bronze for pres ures under 200psi and of steel for pressures over 00 psi.

Figure 9-1 shows a Bourdon t be installed ina gagekase. The Bourdon tube is the shape ofa C and is welded or sliver-b zed to thestationary base. The free and o the tube isconnected to the indicating mechanism by alinkage assembly. The threaded socket, weldedto the itationary base, is the pressuteconnection. When pressure enters the Boadontube, thg tube straightens out slightly and movesthe link connected with the toothed-gear sector.The teeth on the gear sector mesh with a smallgear on the pinion to which the pointer isattached. Thus when pressure in the tubeincreases, the gear mechanism pulls the pointeraround the dial and registers the amount ofpressure being exerted in the tube.

The simplex gage, shown in figure 9-2, maybe used for measuring the pressure of steam, air,water, oil, and similar fluids or gases.

Chapter 9 INSTRUMENTS

TOOTHED GEAR SECTOR

OVAL SHAPEDBOURDON T E

HAIR SPRING

The Bourdon tube vacuum gage, commonlyCASL used on auxiliary condensers to indicate vacuum

SEALED ENO in inches of mercury, is illustrated in figure 9-3.CONNECTING Vacuum g ag e s indicate pressurdp below

LINK atrrfbspheric pressure, whereas pressure gagesindicate pressure above atmospheric pressure.

CONN CLINGLINK SCREWS

The compound Bourdon tube gage (fig. 9-4)uses a single Boiudon tube of such greatelasticity that it can measure vacuum (in inches)to the left of the zero point and pressure (inpounds per square inch (psi)) to the right of thezero point.

The duplex Bourdon tube gage illustrated infigure 9-5 has two separate gear mechanismswithin the same case. A pointer is connected to

MOVEMENTPIVOT the gear mechanism of each tube. Each pointer

SUPPORToperates independently of the other pointer.Duplex gages are commonly used for suchpurposes as slVwing the pressure drop betweenthe inlet side and the outlet side of lube oilstrainers. If the pressure reading for the inlet

38.211AX side of the strainer is much greater than theFigure 9-1.Bourdon tube installed in a

gage case.

SEALED END

STATIONARY BASE

PINIONBUSHING

THREADED SOCKET(PRESSURE CONNECTION)

RFD HAND

I I

POINTER

38.211BX 38.211DXFigure 9- 2. Simplex Bourdon tube pressure gage.

101

107

Figure 9-3.--Bourdon tube vacuum gage.

FIREMAN(

38.211EXFigure 9-4.Compound Bourdon tuke gage.

f:)' 61.3BXFigure 9-6.Indicating mechanism of a bellows

pressure gage.

125 150 us

100

75

SO250

25300

225

CALIBRATING SPRING

ZERO ADJUSTINGSPRING

PANEL.ORBULKHEAD

38.211FX43

Figure 9-5.Duplex Bourdon tube gage.

108102

ZERO ADJUSTING SCREW

4 38.212XFigure 9-7.Diaphragm air pressure gage.

Chapter 9INSTRUMENTS

a 14

pressure reading for the outlet side, the straineris most likely very dirty and is thus restricting'the flow of tube oil through the strainer.

'BELLOWS GAGES

A bellows gage is generally used to measurepressures less than 15 psi. Some types aresatisfactory for measuring draft pressures andfor general low pressure measurements. Thebellows' of t gage is made of stainless steel,brass, ) be um- pper, Monol or phosphorbrow". A bellows 's shown in a gage case infigure'9-6.

When pressure increases in the line to abellows gage, the bellows increases in length andoperates a"system of gears and lever which areconnected to the ,pointer. The pointer then

,registers the higher reading on the dial. When thepressure to the bellows gage decreases, thebellows returns to its normal length, returningthe pointer toward zero. When the pressure tothe bellows is completely yremoved, the

hairspring of %e spoVer returns the pointer allthe way back to zero.

DIAPHRAGM GAGES

Diaphragm gages are sensitive and givereliable indications of small differences inpressure. Diaphragm gages are generally used to

.,measure air pressure in the space between theinner and outer boiler casings.

The indicatiflg mechanism of a diaphragmgage, shown in figure 9-7, consists 9f a tough;pliable, neopreike rubber membrane conntdtedto a metal sPring which is attached by' a simple .link* system to the gage pointer.

One side of the diaphragm is exposed to thepressure being measured, while the other side isexposed te the aftmosphere. When pressure isapplied to the diaphragm, it moves upward,puthing the metal spring ahead. As the spring ispushed up, it moves the pointer, connected to itwith a chain, to a higher reading on the dial.When the pressure is lowered the diaphragmpulls the pointer back toward the zero point. I 0 9

MANOMETERS

A manometer is perhaps the most accurate,least expensive, and simplest instrument formeasuring low pressup, or low pressuredifferentials. A manometer, in its simplest formconsists of a glass U-tube of uniform diameter,filled with a liquid. The most common liquidsused are water, oil, and mercuryt One end of theU-tube is open to the atmosphere and the etherend is connected with the pressure to bemeasured.

Manometers are available in many differentsizes and designs. They all operate on the sameprinciple. Two common types of manometersare shown in figure,9-8i

THERMOMETERS AND PYROMETERS

o 1-k thermometer is aprinstrument whichmeasures temperature. The temperature

103

61.4XFigure 9-8.A. Standard U-tube manometer.

B. Single-tube manometer:

10,

FIREMAN

measured may be that of steam to the mainengines, brine in an ice machine, oil and bearings esin the main engines',4or substances in many other Qlocations. In generpl, a thermometer measureschanges in temperature by utilizing the effect ofheat on the expansion of a liquid or a gas.

Thermorheters are designed as (1)direct-reading, liquid-in-glass type, (2) bimetallictype, or (3) distant-reading, indicating-dial typethermometers.

LIQUID-IN-GLASS THERMOMETERS

Liquid-in-glass thermometers are filled withmercury, ethyl alcohol, benzine, water, or someother liquid suitable for the temperature rangeinvolved. Most of the liquid-in-glassthermometers used in the engineering spaces arefilled with mercury. When a thermOmeter isexposed to a temperature to be measured, heatcauses the liquid in the bulb to expand and rise

48' RECLINED ANGLE

'LEFT DICE ANGLE

Cr INCLINEDANGLE

RIGHT GIDE ANGLE

mkt, NT, .01METALLIC ELEMENT

GAGE DIAL.

Ar,

POINTER

Aet

110 ORO

61.27Figure 0.10. Bimetallic actuator for a thermometer.

in the glass stem. Cold, or the absence of heat,uses the liquid-to contract and fall.

LiqUid-intlass thermometers are designed so,That the face will be in the best positon forreading, ',when the thermometer is installed.Some thermometers with different angles areshown in figure 9-9.

Mercury-filled Thermometers must not bemisused or improperly handled ,,because ofpersonnel hazard. Mercury produces a highlyToxic vapor which is 'hazardous if breathed inexcessive concentration.

BIMETALLIC DIAL THERMOMETERS '*

Bimetallic dial. t ermometers use a bimetalelement for indicati temperature changes on acircular dial. The' bimetallic actuator is asingle-helix coil fitted olosely to the inside of thestem tube. A rise in temperature causes theactuating element to expand. Beause theelement is composed of tw.o thin strips ofdifferent metals with each metal having adifferent rate of expansion, the element expandsby unwinding instead of by expanding againstthe sides of the tube. The pointer shaft issecured to the free end of the element and thusregisters the-amount of element movement on'the dial face. Figure 9-10 shows the actuatingelement of a bimetallic thermometer.

DISTANT-READINGDIAL THERMOMETERS

. 61.26 Distant-reading dial thermometers are usedFiguro 9-9.Tpormometors with angle socks ts. when indicating portions of the instrument must

104

110

Chapter 9IN

BOURDONTUBE

PRESSUREGAGE

CAPILLARYTUBING

MERCURYBULB

61.28XFigure 9-11.Distant-reeding dial thermometer.

be placed at a distance from where thetemperature is being measured. Them e rcury-filled, distant-reading thermo meter,shown in figure 9-11, is the most common typeused aboard ship. There are other types, butthey are not commonly used aboard ship andwill not be discussed.

The mercury-filled, distant-readingthermometer (fig. 9 -I I-) consists of a mercurybulb, capillary tubing, and a Bourdon tubepressure gage. The mercury bulb, the capillarytubing, and the Bourdon tube in the pressuregage are all filled with mercury.

The mercury bulb is the sensing element. Itis inserted and fastened securely (eithk- threaded

4or bolted) in an opening in a pipe lior turbinepump casilig, for instance, where a temperaturemeasurement is desired.

The capillary tubing is constructed similarlyto armored electric cable, but instead of having

TRUMENTS

wires

handleof kinkiwithin the

r cables inside, the armor contains a smallmetal tube. The capillary tubing must becarefully and must be maintained free

twists, so that the mercury columning is not distrupted.

The Bourdon tube pressure gage is the sameas we discussed earlier in this chapter. The gagecontains a Bourd9n tube which has a tendencyto straighten out as the pressure in the Bourdontube increases.

Now, let us put together the three majorunits of the distant-reading thermometer(mercury bulb, capillary tubing, and the pressuregage) and see what happens. Remember that allthree of these units are filled with mercury andthat when the temperature rises, the increasecauses the mercury in the bulb to expand. Theexpansion of the mercury in the bulb causes a

%pressure to be built up in the ca illary tubing.This same pressure is transrakted- hrough thecapillary tubing into the Bourdon tube in thepressure gage. The Bourdon to aightens outand, through an assembly of gears and levers,causes a pointer to move around a dial, whichhas previously been calibrated to showcorresponding temperatures. The expansion ofthe mercury in the bulb-results in a movementof the pointer that is directly proportional tothe temperature applied to the bulb.

105

PYROMETERS

Pyrometers are used to measure temperaturethrough a wide range, generally between 300°Fand 3,000°F. They are used aboard ship tomea u temperatures in heat treatmentfu aces, in exhaust temperatures of dieselen: es, a d for other similar purposes.

e pyrometer includes a thermocouple anda meter. The thermocouple, made of twoissimilar metals joined together at one end,

produces an electric current when heat is appliedat its joined end. The meter, calibrated indegrees, indicates the temperature at thethermocouple. Figure 9-12 illustrates theoperating principle of the thermocouple of thepyrometer.

FIREMAN

izirid. A --LITAL

7e0PCIA71100 0A.50(341M773.127C1104.1011AT0070 09HCA70 700.*072Altrae) I

o 61.34XFigura 9`12. Diagrammatic arrangomont of a

tharmocoupla.

LIQUID LEVEL INDICATORS

In the engineering plant aboard ship,operating personnel must frequently know thelevel of various liquids in various locations. Thelevel of the water in the ship's boilers is anexample of a liquid level that must be known atall times. Other liquid levels that must be knownare the level of the fuel oil in, storagetanks and service tanks, the level of theqvater inthe deaerating feed tank, and the level of thelubricating oil in the oil sumps and reservoirs ofpumps and other auxiliary machinery.

Liquid level indicators, other than soundingrods and ta'es, are constructed in a variety ofdesigns and sizes; some are simple and some arerelatively complex. Some indicators measureliquid level directly by measuring the height of acolumn of liquid.

TANK GAGING SYSTEM

One of the most common liquid levelindicators is the static head gaging system,shown in figure 9-13. This type indicator isgenerally used to measure the liquid level in fueloil storage tanks aboard ship. This system uses amercury manometer to balance a head of liquidin the tank against the column of liquid in themanometer. The balance chamber is located sothat its orifice (opening) is near the bottom ofthe tank. A line connects the top of the balance

1

/-

106

112

chamber to the mercury-filled bulb of theindicator gage, and another line connects thespace above the mercury column to the top ofthe tank. Since the height of the liquid in thetank has a definit4 relationship to the prossweexerted by the liquid, the scale can be caliblatedto show the height (or liquid level). Whe theheight`of the liquid in the tank is known, themeasurement of height can be readily convertedto volume (gallons).

GAGE GLASSES

The gage glass is qne of the simplest kinds ofliquid level indicators. Gage glasses are used onboilers, on deaerating feed tanks, on inspectiontanks, and on other shipboard machinery. Gageglasses vary in design and constructiondepending upon pressure or other serviceconditions.

The liquid level in the gage glass is the sameas the liquid level in the container, and theliquid level can be determined by visual

OIL IN

MERCURY

BASE

CONTROL...

VALVE

COMPRESSED AIR SUPPLY

BALANCE CHAMBER

ORIFICt

Figure 9-13.Static head gaging system..61.5X

( hapter 9 INS! N IS

Figure 9-14.Boiler gage glass installed on a boiler.

observation. A typical boiler gage glass installedon a boiler is shown in figure 9-14.

In addition to the gage glasses. some boilersare equipped with remote. water level indicators.The remote water level indicators are generallyinstalled on the operating level of the boilers toprovide the petty officer in charge with ci readilyobtainable reading of the water level in thesteam drum of the boilers. Figure 9-15 illustratesone type of reIl ate water level indicator.

TUID ME,IERS

Fluid meters are used aboard ship tomeasure flow rate of fuel oil, diesel oil, water,

107ti

° 139.32

gasoline, and other liquids. You cannot get anaccurate measurement of the rate of flow of aliquid through a meter finless the recordedamount is read correctly. Some different typesof dials used on fluid meters are shown in figures9-16 and 9-17. TI R- dial readings are generally inU.S. gallons unless otherwise specified on thedial face. The dial faces shown in figure 9-16 arefar the straight-reading type meter: the dial facesshown in figure 9-17 are for a round readingmeter.

Fo read the stright-reading meter, read fromleft to right and add sthe number indicated bythe smaller pointer above. For example, in part

0

FIREMAN

A of figure 9-16 the reading is 0000280. Part Bshows the reading to be 0000285. As the pointerturns, so does the righiphand, numbered roller.Even though the next higher. number is partlyexposed always read the lesser number,'which.isthe number disappearing frond sight. When thesmall pointer is at 0 all the numbers in thestraight-reading dial will be centrally aligned, asshown in part A and part G of figure 9-16. Whenthe small pointer is at 8 or 9 (part C of fig.9-16), the next larger number on the numberedroller is almost completely exposed, but thelesser number must be read. The dial in part C offigure 9-16 reads 288 gallons, not 298 gallons.

1

To read the round-reading dial face (fig.9-17) take the lesser number of the two betweenwhich the hand points in each circle. Notice thateach circle indicates tens, hundreds, thousands,tens of thousands, etc. Place the number takenfrom the circle marked "tens" in-The unitsposition, place the number taken from the circlenarked "hundreds" in the tens place; and

ww,...1.

41, kt:A.

4.

139.33Figure 9-15.Reroote water level indicator.

114108

14 $.0 ALLONS-414 MS

tJy 41.0

61.13.1XFigure 9-16.Straight reading registers.

g

61.13.2XFigure 9-17.Round reading registers.

10.

Chaptef 9INSTRUMENTS

coittinue similarly for the remaining circles.Each division of any circle stands for one -tenthof the whole number indicated by that circle. Ifa hand is o or near a numbers read that numberinstead of tale next lower number when the handin the circle is on or past 0.

REVOLUTION COUNTERSAND INDICATORS

Measurements of rotational speed arenecessary for the operation of the pumps, forceddraft blowers, main engines, and othermachinery or equipment of the engineeringplant. As a result, various instruments are usedto indicate the shaft speed or to count thenumber of turns a shaft makes.. One type ofinstrument, the revolution counter, which ismounted on the throttleboard in theengineroom, counts the total number of turnsthat are made by a main propulsion shaft. Thesecounters are similar to the speedometer of anautomobile. A typical revolution counter isshoiwn in figure 9-18.

Figu8. Revolution counter.7.143

109

The most common instrument used in theengineering plant aboard ship to measurerotational Speed is the tachometer. For mostshipboard machinery, rotational speed isexpressed in revolutions per minute (rpm). Thetachometers generally used aboard ship are ofthree main types: centrifugal, chronometric, andresonant.

The..CENTRIFUGAL tachometer may beeither portable (single and multiple range) orpermanently mounted. The portable multirangetachometer has three ranges: low (50 to 500rpm), medium (500 to 5,000 rpni), and high(5,000 to 50,000 rpm). Do not shift from onerange to another while the poytable centrifugaltachometer is in use.

Normally, permanently mounted centrifugaltachometers operate off the governor orspeed-limiting assembly. The tachometercontinuously records the actual rotational speedof the rhachinery shaft. permanently mountedcentrifugal tachometer is illustrated in figure9-19.

The portable centrifupj tachometer isoperated manually. A small shaft whichprotrudes from the tachometer case is appliedmanually to a depression or projection on theend of a rotating shaft of a pump, motor`, orother machinery. The centrifugal or rotatingmovement of the machinery ,,soft is convertedto instantaneous values of s1,ecl.on the dial faceof the tachometer. Figure 9-20 shows a portablemultirange centrifugal tachometer.

The portable PHRONOMETRICtachometer, shown in figure, 9-21, is acombination watch and rdvolution counter. Itmeasures' the average number of revolutions perminute of a motor shaft, pump shaft, etc. Thistachometer has an outer drive 'shaft which runsfree when applied to a rotating shaft, until astarting buttori is depressed to start the timingelement. Note the starting button beneath theindex finger in figure 9.21. The chronometrictichOmeter retains readings on its dial after its/drive shaft has been disengaged from a rotatingshaft, until the pointers' are returned to zero.bythe reset button (usually the starting button).

FIREMAN

38.111XFigure 9-19.Permanently mounted centrifugal type tachometer on a forced draft blovkr.

110

116

Chapter 9INSTRUMENTS

Figure 9- 20. Multiranga centrifugal tachometer.

2.66XFigure 9.21. Portable chronometric tachometer.

111

61.17X

The range of a chronometric tachbitieter isusually from 0 to 10,000 rpm andlrom 0 to3,000 feet per minute (fpm).

Each portable centrifugal or chronomJtrictachometer has a small rubber covered wheeland a number of hard rubber tips. Theappropriate tip or wheel is fitted on the end ofthe tachometer drive shaft and held against theshaft to be measured. Portable tachometers ofth0 centrifugal or chronometric type are usedfor iritumittent readings only, and are not usedfol. continuous operation.

The RESONANT REED tachometer,illustrated in figure 9-22, is particularly usefulfor measuring high rotational speeds sjich asthose that occur in turbines and generators. Thistype tachometer is particularly suitable when itis practically impossible to reach the movingends of the machinery shafts. This instrumentgives continuous readings and is capable ofmakin rap , instantaneous adjustments torotational sp d.

1

FIREMAN

Resonance is the quality of an elastic bodywhich causes it to vibrate vigorously whensubjected to small, rhythmic impluses at a rateequa to, or near, its natural frequency. Ip areso ant reed tachometer, resonance provides asimp a but accurate means to measure speed andrate of vibration.

A resonant reed tachometer consists of a setof consecutively tuned steel'reeds mounted in amse with a scale to indicate rpm of the shaft andvibrations per minute (vpm) of the reeds. This

`tachomethas no pointeronly a set ofaccurately tuned reedsand it operates without

direct contact with a moving part under test. Ithas no gears or couplings, and it _requires nooilingiland practically no maintenance.

OTHER ENGINEERING INSTRUMENTS

There are a great number of additionalinstruments and indicators used in theengineering plant. This section will acquaint youwith those additonal instruments which youmost likely will be seeing or working with in theengineering department. These additionalinstruments include superheater temperature

61.16XFigure 9-22.Mounted resonant reed tacImeter.

112

alarms, superheater steam flow indiCators,smoke indicators, salinity indicators, lube oilpressure alarms, engine order telegraph, andmany others.

SUPERHEATER TEMPERATURE ALARMS

Superheater temperature alarms are installedon most boilers to warn operating personnel ofdangerously high temperatures in thesuperheater of the boilers. Some superheatertemperature alarms operate similarly to theBourdon tube pressure gage. As heat is applied,the mercury in the spiral-wound Bourdon tubeexpands, causing the Bourdon tube to move acantilever arm toward an electric microswitch.As the preset alarm temperature is reached, thecantilever arm engages the microswitch, settingof a warning howl or buzzer. The warning signalcontinues until the superheater temperature hasbeen lowered to approximately 10° or 15°F,below the preset alarm temperature. The signalor alarm stops because the mercury in theBourdon tube contracts, moving the Bourdontube, which in turn causes the cantilever arm tomove away from the microswitch, shutting offthe alarin. A diagrammatic arrangement of onetype of superheater alarm is shown in figure9-23.

STEAM FLOW, INDICATOR

Steam flow indicators' 91).1)W the rate of flowof steam through the superheater of

STEEL CAPILLARY TUBE

118

MERCURY FILL ED BULB

PIVOT POINT

SPIRALBOOR DON

TUBE

mICROSwiTcH

ADJUSTER FORSE TTINC. ALARM

TEMPERATURE

CANTILEVERARM

61.31 XFigure 9-23.Superheater temperature alarm.

Chapter 9INSTRUMENTS.

BULL'S-EYELENS

LAMP

3111-48,43.40

.27

LAMP UNIT

UPTAKECASING

LINE OF SIGHT

VISIONGLASS COVER

CLAMPI

[!'" /1N_Irk\.11;,

wed

41: A..

.111:

N w',,w, ADJUSTABLE 'No

1MIRROR ee

REFLECTORUNIT

COVERCLAMP

LOCKNUT

LOCK.NUT

ADJUSTABLEMIRROR

VISION Ut'iT

Figure 9-24.Smoke indicator.

double-furnace boilers. Before fires are lighted inthe superheated side of double-furnace baiitirs,the operator must ensure that a sufficient flowof steam-is passing through the superheater. Theflowof steam is necessary to carry off the heatOf combustion in the superheated side ofdouble-furnace boilers in order to preventoverheating of the superheater tubes, drums, andheaders.

The steam flow indicator is calibrated ininches and is normally set at 2 inches as theminimum low. In other words, fires should notbe lighted in the superheated side ofdouble-furnace boilers until the .pointer on thesteam flow indicator has reached the 2-inchmark, which is an indication of sufficient flowpf steam.

113

1 1

SMOKE INDICATOR

LINES

COVERCLAMP

38.60

Smoke indicators (periscope type) providethe boiler operator With visual indications ofconditions in the stack above the furnace area. Asmoke indicatorIS shown in figure 9-24.

SALINITY INDICATOR

Electrical salinity indicating cells (fig. 9-25)are installFd throughout distilling plakts tomaintain a constant check on the distilled water.An electrical salinity indicator consists of anumber of salinity 'cells ,in various locations inthe plant; for example, in the evaporators,condensate pump discharge, and the air-ejector

1.0

FIREMAN

7150Figure 9-25.Salinity cell and valve assembly.

condenser' drain. These salinity cells are allconnected to a Salinity indicator panel.

a Since the electrical resistance or a solutionvaries according to the amount of ionized saltsin solution, it is possible to measure salinity bymeasuring the electrical 'resistance. The salinityindicator panel is equipped 1 with a metercalibrated to read directly either in equivalentsper million (epm) or in grains per gallon (gpg).The newer type salinity indicators are calibratedin epm.

LUBE OILPRESSURE ALARM

Lube oil pressure alarms are installed oncallgenerators and Inain propulsion engines to signalwhen the lube oil pressure to the bearings isdangerously low. Low lube oil pressure,, cancause a number of casualties that will impair theoperating condition of- the machinery invlved.

wThe lube oil pressure, which is either a rapidly

114

ringing bell or loud siren, receives its signal fromthe bearing that is the most) remote from thelube oil pump. When the alarm is sounded, theaffected machinery must be stoppedimmediately, the cause determined, andcorrective measures taken.

ENGINE ORDER TELEGRAPH

The engine order telegraph (speed indicator),shown in figure 9-26, relays the speed requestedby the officer of the deck while underway to thethrottleman in the engineropm. The engineorder telegraph is generally mounted on thethrottleboard adjacent to the throttle valves, sothat it is readily visible to the throttleman. Thefollowing table lists speed changes which may beindicated via the engine order telegraph.

10

7.116Figure 646.Engine order telegraph.

'A 4

4

IChapter 9INSTRUM NTS

Ahead Stop Astern The wrong direction alarm is connected to1/3 1/3 the engine order telegraph and the main engine2/3 2/3 throttle valves. If the engine order telegraphI Standard Full . indicates "ahead" and the throttleman attempts iII Full to open the astern throttle valve, a loud signal or 'III Plank alarm is sounded. - -

A

Q

121 .

115

b

A Fireinan, you should have. a generalknowled of the basic operating principles ofthe various pes' of pumps used by the Navy.Pumps are used to move any substance whichflows or which can be made-to flow. Whenthinking of the term pumj,ing, you probablythink of movineWater, oil, air, steam, and othercommon liquids and gases. Substances such asmolten Metal, sludge, and mud are alsO fluidsand can be pumped with specially designedpumps. .

A pump is a device which suses an externalsource of power to Apply a force to a fluid inorder to pc ove the fluid from one place toanother. *pump transforms energy from theexternal source (such as ar4 electric motor orsteam turbine) "nto :mechanical kinetic energy,which is reveal d by the motion of the fluid.This kinetic en i en used to do work,such as: to raise a liquid,- from one level toanother, as when lifting 'Water from a well; totransport a liquid through a pipe, as in an oilpipeline; to move a liquid against someresistance as when filling a boiler under pressure;or to force a liquid througha hydra is systemagainst variptus resistances.

Aboard ship, pumps are used for a numberof essential services. Pumps,supply water tp theboilers, draw condensate from the condensers,supply sea ,water to the firemain, circulatecooling water for coolers and condensers, pumpout bilges, transfer fuel. oil, 4upply sea water tothe distilling' plants, and serve ;many otherpurposes. The operation of the ship's propulsionplant and of almost all the auxiliary machinerydepends on the proper operation of pumps.,gump failure may cause failure Of an entirepower plant, although most plan s have twopumpsa main pump and a standb Dump.

CHAPTER 10

ob.

PUMPS, VALVES, AND PIPING

r

4

If a system has a 'pump, it must also containdevices for controlling the volume of,flow, thedirection of flovy, or theoperattng pressure ofthe system. A device that performs one or moreof these control functions is called a VALVE.

In addition to 'pumps and valves,. in thischapter we shall discuss pipipg which is a vital

s

part of the sliip's engineering plant.

PUMPS4

Pumps are classified by their ,design .andoperational features. Pumps are further classifiedby the type .of. movement that causes thepumpip-rr'actionv (reciprocating, rotary,centrifugal, propsller, or jet pumps). Pumps arealso classified by the rate of speed, the rate ofdischarge, eand the method of priming. Somepumps run at variable speed; others at constantspeed. Some pumps have a variable capacity;others discharge at a constant rate. Some pumpsare self-priming; -others require a positivepressure on the suction (intake) side before they

,can begin to move a liquid.Regardless of classificatippump must

have- a POWER END and asPe.-OiD .END:-Thepower. end may be a *am turbine, areciprocating steam engine; steam jet, or anelectric motor. In . steam-driven pumps,' thepower end is oftenalled the STEAM END. Thefluid end is generally called the PUMP END; butit may be called the LIQUID END, theEND, thr-011--....EXILgs.,--the GAS N toindicate' thf nature of the IPuid substpce b ing

Pufps can be divided into groups accofding.to the principles on which they operate. Mostpumps fall into five pain types: reciprocating,

A R

'Rumpedi

116

4%,

clvI

Chapter 10 PUMPS, VALVES,

rotary, centrifugal, 'propeller, and jet. Each typeor'pump is especially suited for some particularkind of work.

RECIPROCATING PUMPS

The hand water pump commonly used onfarms is a good example of the reciprocatingpump. The reciprocating ptgair, derives its namefrom the back and forth or up and downmovement of the Piston or plunger inside acylinder. These pumps are used on modern shipsas emergency feedwater pumps and asemergency fire and bilge pumps. ReciprocatOripumps are used for emergency purposes becausethey are easy to operate and can be startedsafely by relatively inexperienced personnel.These pumps are also reliable for starting undercold conditions.

A single- acting pump is one which takes asuction on one stroke only, known as thesuction stroke. On the return strokecalled thedischarge strokethe liquid is forced out of thecylinder. Figure 10-1A illustrat?s the operatingprinciple of a single-acting reciprocating pump.

The principal parts of a .single-actingreciprocating pump are a Fylindera piston, anda valve system. The piston fits ?nugly in thecylinder and is moved up and down in thecylinder by the punipp4haft. Most of thesepumps are steam-dtilkn. "The pump shaft is acontinuation of the piston rod of the steamcylinder. ,

On the down stroke, the valves in thebottom of the cylinder arerclosed and the waterin the lower part of the cylinder is forced upthrough the valves in the pistbn: On the upstrokes, the weight of the water above the pistoncloses the piston valves. As the piston movesupward, it draws the water from the suction lineinto the ylinder through the cylinder valves.The water abo the piston leaves the pumpthrough an outlet line or a spout.

The double-acting Ohm shown in figure10-1 B delivers a steady stream of water underhigh pressure. Double-acting pumps are, alsosteam-driven. The pump is connected directly tothe piston rod of the steam cylinder. Thesepumps have the same general parts and operateon the same general principle as the single-acting

AND PIPING

139.34Figure 10-1.Orrating principle of two typos of

reciprocating pumps.

1

type except that the valve .system is arra geddifferently, and an air ,chamber is added to,..

maintain the pressure when the piston is at thetop and bottom of each stroke. ....._ ,

A stream of water is forced out of thedouble-acting pump on both 'the up and thedown strokes. On the up stroke, the water abovethe piston is forced out through the upper outletvalve. At the same time, 'fater is being drawninto the space below the piston through thelower 'inlet valve. On the down stroke, the waterbelow the piston is forced- out of (dischargedfrom) the cylinder through the lower outletcalve and a new charge of water is drawn intothe top of the cylinder through the upper inletvalve.

117

Reciprocating pumps are often calledPOSITIVE DISPLACEMENT pumpsthat is,each discharge stroke displaces a definite''amount of liquid, regardless of the resistancesagainst which the pump is operating. A reliefvalve must be installed in the discharge line torelieve any excess pressure. st

The operation of the reciprocating pumpgenerally depends on a valve system whichdireas the steam First in d one end of the

123

STEAM rrEST

FIREMAN

139.35Figure 10-2.Operating principle of D-shaped slick

valve of a redprocating pump..

cylinder and then into the other end. The steamis allowed to escape from the cylinder after ithas served its purpose. Steam to and from thecylinder passes through two ports (opepings),one in each end of the cylinder. Thisarrangement is quite similar to the manner inwhich the water passes through thedouble-acting water pump described previously.

One valve design consists of a D- SItAPEDSLIDE VALVE (D-valve) that is actuated by alinkage attached to the piston rod. (See fig.10-2.) The steam chest which is attached tothe cylinder is connected through a stop valve tothe auxiliary 'steam line. When the piston reachesthe top of its sfroke, the valve-operatingmechanism moves the valve down to theposition shown in figure 10-2A. The portconnecting the steam chest to the 'pace at thetop of.the cylinder is uncovered. Steam from thechest flows through this port, exerts a pressureon the top of the piston, and forces itdownward.

At the same time, the space belolk the pistonis connected with the exhaust port through arecess in the back of the valVe. As the pistonmoves downward, tke steam that fills this spaceis forced out through the exhaust port.

As the piston nears the bottom of its stroke,the valve mechanism moves the D-valve to theposition shown in figure I0-2B. This, movement

fivers the lower port. Steam froth the chestnow flows into the lower-re of the cylinderand pushes the piston upward. The upper

a

or.

118

124

Ant .1171

'EXI1AOSTPORT

SILIVE OTEALi

PACE

STGALI PORTPO( PILOTVALVE

P15*

UAW STEPL5T014 TVALVE

TEAL, PILOTVALVE

AUTgAWDff

.

32.99Figure 10-3.Piston-type valve gear for steam and of

reciprocating pump.

cylinder port is connected to the exhaust portthrough the back of the valve. As the,pistonrises, it pushes the exhaust steam out at the toPof the cylinder through the exhaust port.

Figure 10-3 shows the piston valve gearcommonly used aboard ship. It performs thesame function as the D-valve, but the movementof the valve is controlled by the difference in thesteam pressure between the inlet and the outlet.The piston valve gear consists of a mainpiston-type slide valve and a pilot slide valve.Since the rod from the pilot valve is connectedto the pump rod by a valve-operating assembly,the position of the pilot valve is controlled bythe position of the piston in the steam cylinder.The pilot valve furnishes actuating steam to themain piston valve; this in turn admits steam tothe top or to the bottom of the steam cylinderat the proper time.

Regardless of the type of valve used, thecontinued operation of tholyump consists offeeding steam into one end" of the cylinder andexhausting it from the other end. The direction

Chapter 10PUMPS, VALVES, AND PIPING

of steam flow (in and out of the cylinder ports), is reversed at the end of each stroke of the

piston. .

Starting a recipfocating p p Is quitesimple. First, open the proper v s in thesuction and discharge lines before sta ing thepump. Next, open the exhaust valve and thecylinder drains. Then open the throttle valveslightly, or "crack" it to feed enough steam Intothe cylinder to warm it. Adjust the throttle toperate the pump at a slow speed until live

c1s eam begins to come out of the drains. Now

ose the drains and adjust the throttle tooperate the pump at the desired speed.

When securing a reciprocating pump, closethe throttle first, and then close the exhaustvalve. Next open the cylinder drains and close

,,, the valves in the suction and discharge lines.After the steam cylinder has drained, close thedrain valves.

Variable Stroke Pumps

Aboard ship, variable stroke pumps (positivedisplacement) are used largely onelectrohydraulic steering gear, elevators, cranes,and anchor windlasses. In these applications, thevariable stroke pump is referred to as the A-endof the drive system and the hydraulic motorwhich is driven by the A-end is referred to as theB-end. By controlling the pumping action of theA-end, you can run the motor (B-end) in'eitherdirection and vary the speed from zero to themaximum rate. On some naval ships, variablestroke pumps are also used as in-port andcruising fuel oil service pumps.

Although variable stroke pumps are oftenclassified Ai rotary pumps, they are actuallyreciprocating 'sumps. They operate on aprinciple similar to that of -a single-actingreciprocating pump. A rotary motion isimparted to a cylinder barrel or cylinder blockin the pump by means of a constant-speedelectric motor, but the actual pumping is doneby a set of pistons reciprocating inside a set ofcylinders.

Let us discuss the way that the rotarymotion is changed to reciprocating motion.

WW1

tWil" cnt-411

rates:4

(A)

11,11=41

SHAM1110-0(

W:1Nati

11

139.37Fiouro 10 4. Operating principlo of a Waterbury

Figure 10-4 illustrates the operatingprinciple of a Waterbury variable-volume pump.This pump is used as a variable-speed powertransmission in the steering gear and thegun-training mechanism aboard ship. It is alsoused in those systems where it is necessary tocontrol the pump output within very narrowlimits.

In the Waterbury pump the p,dping is doneby a set of pistons which move back and forthwithin close-fitting cylinders. The oil enter andleaves the cylinders through ports or pass es inthe cylinder heads. The pistons are operat d bythe cam action of a tilting plate. This me od ofchanging rotary motion to reciprocating (backand forth) motion is demonstrated by the deviceshown in figure 10-4.

This demonstrator consists of a cykpderbarrel and a tilting plate attached to a shaft, asillustrated in figure 10-4A. The tilting plate isfastened to the shaft by a universal joint which'permits it to tilt in any direction. Theconnecting rods (piston rods) rest in sockets inthe tilting plate and are, attached to pistonswhich slide up and down in the cylinders. Whenthe handwheel is turned the complete assemblyturns with it.

When you place the demonstrator on asloping surface the tilting plate will tip or, tiltand assume the same angle as the block. Thepistons on the low side will be drawn down in

5

PLA'f

P Sfth

1:1001 RU;)

*vt hnfR BARRit

CONTROL SHP!

4:1

TIL 71NG

\. Btu, K

11;

'HAFT TRUNNION BLOCK

DIAGRAM - TILTING BLOCK POs"ilikk,

FORWARD

1

REVIR4

I

I

-a

SOCKET RING

MAIN

SHAFT

Chapter 10 PUMPS, VALVES, AND PIPING

the cylinders, and those on the high side will bepushed up. In figure 10-4A the number 1 pistonis in the lowest position; number 3 is in thehighest.

Now turn the handwheel to the right, andsee what happens. As the far side of the tiltingplate moves up along the surface of the block,the connecting rods and pistons on that side willbe raised. The near side of the plate will bemoving down along the block surface and thepistons on this side will move down in thtcylinders. The operation is continuous. Eachpiston moves up during half of each revolutionaround the shaft, and moves down during theother half.

The stroke of the pistons (the distance thatthey move up and down during each revolutionof the shaft) depends on the slope or tilt of thetilting plate. In figure 10-4B the demonstrator isresting on a level surface, and the tilting plate isparallel to the bottom of the cylinder barrel.When you turn the handwheel now, the tiltingplate will' not move up and down, and thepistons will remain in the same position in thecylinders.

So far, the demonstrator has been used toshow that the pistons will move up and down inthe cylinders when the shaft is turned with theangle plate tilted. The device can be convertedinto an oil pump by adding an adjustable tiltingbox to control the tilt of the tilting plate and byplacing a valve plate on top of the cylinderbarrel. The valve plate has two elongated portswhich allow the oil to flow into the cylinders onone side of the pump and out on the,other side.When the tilt of the tilting plate is increased, thestroke of the pistons is increased and more oilpasses through the pump. Tilting the tittingplatein the opposite direction reverses the directionof the oil flow.

The variable stroke axial piston pump (fig.10-5) has the same pOncipal parts as thedemonstrator just described in figure 10-4. Themoving parts are enclosed in a pump case that iskept filled with oil. These pumps are mounted ina horizontal position and are usually driven byan electric motor.

ROTARY PUMPS

All rotary pumps work.by means of rotatingparts which trap the liquid at the suction side ofthe pump casing and force it through thedischarge outlet. Gears, screws, lobes, and vanesare commonly used as the rotating elements inrotary pumps.

Rotary pumps (positive displacement) aremost useful for pumping oil and "other heavyviscous liquids. They are also used fornonviscous liquids, such as water or gasoline,where the pumping problem involves a highsuction lift. Rotary pumps are used for fuel oilservice, fuel oil transfer, and lubricating oilservice. These pumps are self-priming, becausethey are able to remove air from the suctionlines and produce a high suction lift (or asatisfactory vacuum).

The simple GEAR PUMP, shown in figure10-6 is frequently used in the lulricatingsystems of fuel oil and water pumps, forceddraft blowers and other auxiliary machinery.This type of pump has two spur pars whichmesh together and rotate in opposi+ directions;one is the drivinittl tthe other is the drivengear. The driving gear is tached to the shaft ofthe electric motor or steam turbine that drivesthe pump; the driven gear is in mesh with thedriving gear and is driven by it. The gears mustfit very closely within the case so tliat the liquidwill not leak back to the suction side of thepump. The parts are lubricated by the liquidbeing pumped.

127121

DISCHARGE

SUCTION

Figure 10.8. Action of simple gear pump.38.108

FIREMAN -

At first glance, you might think that theliquid passes be n the two gears. This is nottrue. As the gea rotate, the liquid is trapped inthe spaces bet en the gear teeth and the pumpcase and is ca *ed around to the discharge sideof the pump. As the teeth come in mesh, theliquid is squeezed out of these spaces and is keptfrom returning to the suction side of the pump.Pressure is built up and forces the liquid out ofthe pump into the discharge line.

There are several variations of the simplegear pump. One kind has herringbone teeth (fig.10-7) which make little noise and maintain aneven pressure. Another kind has three lobes oneach gear instead of teeth. Lobe pumps andsome helical pumps have timing gears whichrotate the pump parts. All of these pumpsoperate on the same principle, as the simple gearpump just described.

SCREW PUMPS represent still another typeof positive displacement rotary pump. In thescrew pump, the liquid is trapped and forcedthrough the pump by the action of rotatingscrews. Screw pumps have few moving parts andno valves to get out of order. They are widelyused aboard ships as fuel oil and lubricating oilservice pumps. They may have two or three

HAND DRIVE

11111,11.1111

-38.104

Figure 10-7.Herringbone gear pump.

IDLER

ROTOR HOUSING

FLEXIBLECOUPLING

UPPER THRUPLATE

00WER ROTO4

IDLER

DISCHARGE

SPACERRING

ROTOR HOUSING

IDLERLOCATINGCAPS

SUCTION

poneLOCATING

OWERLATTROSTPE

47.80Figure 10- 8. Cutaworview of triple screw, -

high pitch pump.

screws and are divided into high pitch and lowpitch types.

Tltie triple screw pump (high-pitch)illustrated in figure 10-8 has three screws orrotors which revolve within a close-fitting"housing. The power rotor in the center is inmesh with sand drives) the two idling rotors(idlers).

The suction line is connected to the pumpintake, which in turn opens into the chambers atthe ends 'of the rotors. As the rotor turns, theliquid flows in between the threads at the outerend each pair of screws. At the end of thefirst turn, a spiral-shaped slug of the liquid istrapped when the ends of the threads come inmesh again. The threads carry the liquid alongwithin the housing toward the center of thepump and to the discharge opening.

CENTRIFUGAL PUMPS

Centrifugal pumps are used in the feed, freshwater, and fire main systems of the engineering

122

128'

Chapter 10PUMPS, VALVES, AND PIPING

plant. There are many types of centrifugalpumps (feedwater booster, condensate, andfire), but all operate onthe same principle.Centrifugal pumps canhandle large quantities ofa liquid and deliver it at a high pressured. Thesepumps may be .driven by a steam turbine, anelectric motor, or a diesel engine. They do notoperate on the positive displacement principle,but depend on centrifugal force to move theliquids through, the pump and to maintain thedesired Pressure. (See fig. 10-9.)

When a body revolves in a curved path, itexerts a "centrifugal force" upon the , ecasing, or whatever means is used restrain it.from moving in a straight (tangen' al) line. Forexample, centrifugal force is the f rce that holdsthe water in a pail when you swin it in a circleOver your head. If there happens to be a hole inthe bottom of the pail, the water will squirt out,even when .the pail is upside down.

The simple centrifugal pump shown in figure10-9 has only one main moving part. A wheelcalled an impeller is connected to the drive shaftand rotates within the pump casing. The casinghas the same spiral shape as the snail's shell. Thewater enters the pump through the inlet pipe,which empties into the center of the casing. Thelocation of the outlet passage corresponds to theopening in the snail's shell through which thesnail emerges.

The suction connection is so designed thatthe liquid is guided from the suction chamber ofthe casing to the center or' "eye" of the impeller.As the impeller rotates, it carries the wateraround with it. The centrifugal force resultingfrom this rotation pushes the water away fromthe center and holds it against the inside of thepump casing. As the water flows along the insideof the spiral-shaped casing, it is diverted throughthe outlet opening and passes into the dischargeline.

Centrifugal pumps are not self-priming: theyshould NEVER be run while empty. Theimpeller fits very closely into the sides of thecasing and depends on the liquid being pumpedto supply the necessary coolant. This type ofpump is usually installed below the level of the

123

tank from ,which suction is' to be taken. Whenthe intake valve is opened the liquid flows intothe pump arid primes it. The vent cock shouldbe opened until all air is purged front the pumpcasing.

A single-impeller pump will maintainpressures up to 150 psi. Where higher pressuresaye required the pump is designed with from twoto ',six Openers. The pressure is raised bysucceksive stages. The outlet from the firstimpeller is connected to the inlet of the secondimpeller and so on through all the stages.

PROPELLER PUMPS

Propeller pumps ary used on some ships ascirculating water pumps. (See fig. 10-10.)Propeller pumps closely resemble centrifugalpumps in design and operation but do not usecentrifugal force for their operation.

Propeller pumps are used on some ships ascirculating pumps (fig. 10-10).

CASINGEND PLATE

SUCTION

VENT COCK DISCHARGE

CURVED VANES

IMPELLER

CASING

ENDPLATEJOINT

DRAINCONN.

VOLUTEDIFFUSER

139.38XFigure 10-9.-1-s sting principle of a centrifugal pump.

129,

FIREMAN

STEAM CHEST'

BULL GEAR

THRUST BEARING

WATER OUTLET

aA

TURBINE CASING

EXHAUST

STUFFING BOX aPACKING RINGS

THRUST BUSHING

WATERLUBRICATEOBEARING

'PROPELLER'

WATER INLET

Figure 10-10.Main condenser circulating (propeller) pump (showing reduction gearing).

The propeller pump has a propeller closelyfitted into a tubelike casing. The propellerpumps the liquid by pushing it in a directionparallel to the shaft.

Propeller pumps must be located eitherbelow or only slightly above the surface of theliquid to be pumped, since they cannot operatewith a high suction lift.

124

47.37

JET PUMPS

All the pumps previously described requiremotors or turbines to drive-them. However, jetpumps have no moving parts. The flow throughthe pump is maintained by a jet of water orsteam which passes through a nozzle at a highvelocity.

s.4

Chapter 10PUMPS, VALVES, AND PIPIT

Jet pump's' are generally classified asEJECTORS (which use a jet of steam to entrainand transport air, water, or other fluid) andEDUCTORS (which use a flow of water toentrain and pump fluids). The basic principle ofoperation of these two devices is identical.

A simple jet pump of the ejector type isshown in figure 10-11. In this pump, steamunder pressure enters the chamber (C) through apipe (A) which is fitted with a venturi-shapednozzle (B) having a reduced area which increasesthe velocity of the steam., The

, fluid in thechamber at pbint F, in' front of the nozzle, isdriven out of the pump through the dischargeline (E) by the force of the steam jet. The size ofthe dischaige line increases gradually beyon"d thechamber to decrease the velocity of thedischarge. As the steam jet forces some oftthefluid from the chaniber into the discharge line,pressure in the chamber is lowered and thepressure on Plig- surface of the supply fluid forces'

1

E

ATMOSPHERICPRESSURE

Figure 10-11.Jet pump (ejector type).75.283

125

the fluid up through the inlet (D) into thechamber and mit through the discharge line.Thus, pumping action is established.

Jet pumps of the ejector type are'occasionally used, aboard ship to pump small.quantities of drainage overboard. Their primaryuse on naval ships is to remove air and o'c'hernoncondensable gases from the main andauxiliary condensers.

Figure 1042 shows a portable eductor ofthe type found in damage control lockers. Theprinciple of operation is the, same as thatdescribed for the ejector type of jet pump;. butwater is used instead of steam. All the waterwhich enters the large end of the jet must go outthrough the small end. Since the exit end issmaller than the entrance end, the water leavingthe jet will have a greater velocity than it hadupon entering the jet. The venturi-shape of thediverging nozzles causes a low pressure area,creating suction which draws water through thestrainer and entrains it through the divergingnozzle. This ensures a constant flow.

Eductors may also be used for salvage workand with fog or foam equipment. Eductors willoperate when entirely submerged in a floodedcompartment b and will discharge against amoderate pressure.

Although fire and bilge pumps are still beinginstalled in new ships, fixed-type eductors arethe principal means of pumping water overboardthrough the drainage system. By the use ofeductors, centrifugal fire pumps , can serve asdrainage pumps without having to run the riskof fouling the pump with debris present in thebilges; this is especially useful when there hasbeen damage to a ship.

CONSTANT-PRESSUREPUMP GOVERNORS

Constant-pressure pump governors used inthe Navy are applied almost entirely tosteam-driven pumps, both rotary and centrifugaltypes. A constant-pressure pump governoroperates to maintain a constant dischargepressure, regardless of pump capacity or output.

131

FIREMAN

DISCHARGEOVERBOARD

IDIVERGINGNOZZLE

DISCHARGE FROMFIRE PUMP

VENTURI

STRAINERSUCTION]

Figure 10-12.Eductor.

The constant-pressure pump governor(sometimes referred to as pressure regulating)consists essentially of an automatic throttlingvalve installed in the steam supply line to thepump's driving unit. A pipeline connects thegovernor to the pump's discharge- line.Variations in discharge Pressure, or in pressuredifferential, actuate the governor, causing it toregulate the pump speed by varying the flow ofsteam to the driving unit.

126

o°

47.48

A constant-pressure pump governor for alubricating oil service pump is shown in figure10-13. The governors used on fuel oil servicepumps and on main feed pumps are of the sametype. The size of the upper diaphragm and theamount of spring tension vary on governors usedfor different services. You will find detailedinformation concerning the operation andadjustment of governors in chapter 9470 ofNav Ships.Technical Manual.

132 if

I

I i-,,,,ii'-ter

ss:

1:,, ADJUSTING SCREW

DIAPHRAGM g g1.01 -7.7,6i411'. °ifotsmarlili I\

1if-.44040 k.ROM PUMP DISCHARGE ; III r

DIAPHRAGMIlk 4111

r 4PPbr,-

0

NEEDLE VALVE

DIAPHRAGM GUIDE

AUX. VALVE

Ir.!DIAPHRAGM

NINI

4111-1.-PISTON

I i 1, ammur icipur a;LimNE+

4"-- ki IIIIII*

N.

11Air-i 'TNo iv Ito zi

7 IOU jrLI' 1114

MAIN VALVE .

I

38.90Figure 10-13.Constant-pressure pump governor.

1 3127

FIREMAN

VALVES

Most of tile equipment in the engineeringspaces is operated by either opening or closingthe valves. A valve is a device for stoppingand/or controlling the flow of a fluid (liquid orgas) through as pipe or an opening. Valves areinstalled in every piping system aboard ship.You will find them in the fuel line, thefeedwater pipes, and the steam lines. In additionto the large valves which control the flow .offluid in the lines, there are small valves whichpipe the flow around the' larger ones. Thesesmall valves are called bypass valves which areused to equalize pressures.

Valve, designs vary greatly to meet servicedemands. Most valves are classified as stop valves(globe, gate, plug, piston, butterfly, and needleValves), check valves, or combination stop-checkvalves.

Valves can be operated in various ways.They may have hand wheels, air or hydraulicpistons, or they may be operated by gravity, orby a solenoid.

STEP VALVES

top valves are used to close off a pipe orope g so that the contained fluid cannot passthrow . Some valves can be closed partially tocut down or regulate the flow of fluid.

The typical stop valve consists of the body,an opening (port) through which the fluid flows,a movable disk for ,closing this port, and somemeans to raise and lower the disk. In the closedposition, the disk fits snugly into the port,closing it completely. When the valve is open,the disk uncovers the port, allowing the fluid topass through. Each type of stop valve has adifferent mechanical arrangement for closing theport in the valve.

Globe Valves

Globe valves generally derive their namefrom their body shape. (Other types of valvesmay also have globular bodies; hence, the namemay tend to be misleading.) A cross-sectionalview of a globe stop valve is shown in figure

10

2

12

13

07

19

3

0

10

0

a

LIST AP PARTSPART NO. NAME OF PART

1 VALVE am.2 SONNET3 STEM.4 DISk NUT5 DISK0 BONNET STUD1 0ONNET STUD NUT8 BONNET BUSHING9 OLAND10 GLAND FLANGE11 PACKING STOP RING12 GLAND STUD13 GLAND STUD NUT14 SET SCREW15 HANOWHEELIC HANDWHEEL NUT17 PACKINGID BONNET GASKET

'19 DISK WASHER

- .38.117Figure 10-14.Cross-sectional view of globe

stop valve.

10 -14. -Globe valves are widely used, throughoutthe engineering plant for a variety of services.These valves may be used partly open as well asfully open or fully closed, and are suitable foruse as throttling valves.

The moving parts of a globe valve consist ofa disk, valve stein, and a handwheel. The stem,which connects the handwheel and the disk, isthreaded and fits into threads in the valvebonnet. When you turn the handwheel the stemmoves up or down in the bonnet, carrying thedisk with it The valve is closed by turning thehandwheel clockwise and opened by turning itcounterclockwise.

The valve should never be jammed in theopen position. After a valve has been fully

-opened, the handwheel should be turned.towardthe closed position one-half turn. Unless this isdone, the handwheel is likely to freeze in theopen position, and it will be difficult to closethe valve. Many valves have been damaged in thismanner. Another reason for not leaving globevalves fully open is that it is sometimes difficultto tell whether a valve is open or closed. If avalve is jammed in the open position, the stemmay be damaged or broken by someone whothinks that the valve is closed Ao,r1 tries to forceit open. Valves that are exceptions to the aboverule are called BACK SEATING valves.

128

134

Chapter 10 PUMPS, VALVES, ANti PIPING

WHEEL

YOKE SLEEVNUT

YOKE

YOKE SLEEVE

GLAND

PACKING_/

STEM

BODY BONNETBOLTS

GATE

BODY SEATRINGS

GUIDERIB

7

BONNETBUSHING

Y

"BONNE9

BODY

11.317XFigure 10-15.Cutaway view of gate stop valve

(rising stem type).

ti

Sometimes the operation of a back seating valvewill require that it be fully opehed. Wheneverthis is so, special instructions to that effect willbe given. These valves are so designed that, whenfully open, the pressure being controlled cannotreach the valve stem packing, therebyeliminating possible leakage past the packing.

129

The edge of the port, where the disk touchesit, is called the valve seat. The edge of the diskand the seat are machined and ground togetherto form a tight seal. The rate at which the fluidflows through the valve is regulated by thepgsition of the disk. When the valve is closed,the disk fits firmly against the valve seat. Whenit is open, the fluid flows through the spacebetween the edge of the disk and the seat.

Packing is placed in the stuffmg box or spacethat surrounds the valve stem and is held in placeby a packing glarid. With continued use of thevalve, the stem will gradually wear the packingaway and a leak may develop. You can generallystop a slow leak by tightening the gland a turnor two. If this fails, pressure should be removedfrom the valve and the packing should be

-renewed.

135

Gate Valves

Gate valves (gg. 10-15) operate on the sameprinciple as the gTobe valve, but they have a gateinstead of a disk. The port is the full size of thepipe and extends straight through the valve. Thegate is connected to the valve stem aid is raisedor lowered by turning the handwheel. When thevalve is in closed position, the wedge-shaped gateblocks off the port; in open position, the gate isdrawn up into a recess in the,,top of the valve.

Gate valves are used when\ a straight-lineflow through the valve is desirable. They do notwork well as throttles because they tend tochatter. Therefore, gate valves are usuallyoperated in the fully open or shut position.They are often used in water lines.

Plug Valves

Plug valves (sometimes referred to as plugcocks) are frequently used in gasoline and oilfeed pipes as well as in water drain lines. Theordinary petcock is a good example of thivalve.

The body of a plug valve (fig. 10-16) isshaped like a cylinder with holes or ports in thecylinder wall in 'line with the pipes in which thevalve is mounted. Either a 'cone-shaped or icylindrical plug, attached to the' handle, fitssnugly into the valve body. A hole boredthrough the plug is in line with the po in thevalve body. Turning the plug valve h dle

(

FIREMAN

O

LUBRICANTSCREW

PLUG

SUPPORT-SPRING

NON-LUBRICATED VALVE

CHECKVALVE

PLUG

*S.

LUBRICATED VALVE

Figure 10-16.Plug valves.

(which is in line with the hOle in the plug) linesup the hole in the pimp with.the ports in thevalve body so that fluid can Pass througi thevalve. The flow can be stopped by turning the"plug 90° (one-quarthr turn) from the openposition.

Some plug valves are designed as three-wayor four-way selector valves. Three or more pipes.'are connected to a single valve in line with thesame number of ports in the cylinder wall. Twoor more holes drilled in they plug provide avarkty of passages through the valve. When avalve of this kind is located in a fuel line, theliquid may be drawn from any one of two orthree tanks by setting the handle in differentpositions.

Needle Valves

Needle valves are used to make relativelyfine adjustments in the flow of fluid. A needlevalve has a long tapered point at the end of thevalve stem. This needle acts fs a disk. Because ofthe long taper, part of the needle passes through

fr

4

139.39X

the opening in the valve seat before the needleactually, seats. This arrangement pefmits a very

... gradual increase or,decreast- in the size of-theopening and, thus, allows more praise eontrolinf flow than can be obtained' with an ordinaryglobe valve.

- Butterfly, Valves.

130

Butterfly valves are used for liquid serviceonly. The disk in this type valye is flat anoperated by turning the hand lever on the steWhen the lever is positioned 90° to the pipingthe valve is fully open;lhe valve is in the fulclosed-position when the lever is in4ine with thepiping.

CHECK VALVES

Check valves permit a flu" o flow througha line in only one direction...They have manyuses, 'bothaboard ship and ashore: The air valvesin automobile tires, the valtrig in an ordinawatef pump, end the feedwater check valvekon

136

Chapter 10 PUMPS, VALVES, AND PIPINGDISK NUT

CAP

HINGE PIN

DISK

11.319XFigure 10 -17. Swing -check valve.

a steam drum are examples of check valves. Allof these valves open and close automat butsome have a handle or handwheel to 15ck themclosed or to limit the size of the opening.

The port in a check valve may be closed by adisk, a ball, or a plunger. In some valves a springcloses the valve, while in others the weight of

.the disk or ball holds the valve against the seat.The valve opens when the pressure on the inletside is greater than the pressure on the- outletside of the valve. It closes automatically whenthe pressure on the inlet side is less than that onthe outlet 'side. Figure 10-17 illustrates aswing-check valve and figure 10k18 showslift-check valve. These valves are often installedin drain lines, where it ibe in only one dire

STOP-CHECK VALVES

portant that the flow

As you have seen, most valves can beclassified as being either stop valves or checkvalves. Some valves, however, can -function aseither a stop valve or as a check valve, dependingon the position of the valve stem. These valvesare known as STOP-CHECK VALVES.

6

111.320

Figure 10 -18. Cutaway view of lift-check valve.

Two similar stop-check valves are shown incross section in f(gure 10-19. As yoU can see, theflow and operating principles df this type valvevery much resembles the check valve. However,the valve stem is long enough so that when it isscrewed all the- way doWn it holds the diskfirmly against the seat, thus preventing any flowof fluid. In this position, the valve acts as a §topvalve. When the stem is raised, the disk can beopened by pressure on the inlet side. In thisposition, the valve acts as a check valve, allowingthe flow of fluid in only one direction. The

td maximum lift of the disk is controlled by theposiVon of the valve stem. Therefore, the'position of the valve stem can limit the amountof fluid passing through the valve even whenvalve is operating as a check valve.&v. Stop -check valves are usedlocations throughout the engineering plant.Perhaps -"the most° familiar example is theso-called boiler feed-check valve, which isactually a stop-check valve rather than a truecheck valve. StRp-check valves are used in many

'drain lines; onkathe discharge side of "manypumps; and as exhaust steam valves on auxiliarymachinery.

in various

131

137a-

IFIREMAN

THROTTLE VALVES

LIST OF FARTS=NY NO NAME OF MOS

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OMRel OFT

4 ST QM rttracun5 r,onv 7'0 GLAND7 yoxe, 7:tratino0 STEM

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11.1911PREM15 4.,ney STUD NUT10 RELIEF PLUG

FEAT ninomen

19 GLAND RANGE20 MK! ou^mo at* COrZW21 ARM HUT

FTOTo 10-19.Stop-chock volvos.

A throttle valve is inst Iled in the mainsteam line just ahead of he engine. It is.operated by a handwheel and can be opened orclosed quickly for starting and stopping. These

2ves can also be set at any.in-between posit*tOiregulate the speed of the engine. Unlike checkvalves, they are installed to that the steam

'pressure tends to close rather than open them.The pressure in the main steam lines,of some

installations is 600 psi. The disk of a throttlevalve 6 inches across has an area of about 28square inches. Therefore, the force exerted onthe valve disk tending to keel; it dosed is 16,800pounds (600 X 28). Throttle valves are designedto equalize this force, so that they can beopened easily.

A double - poppet; throttle valve is two valvesin one. It has two ports and rwo disks attached

132

138

11.321

)1to a single stem. Both valves open or close at thesame time whenever the handwheel is turned.The ports and the disks are so designed that thesteam tends to close one of the disk valves andopen the other. Figure 1040 illustrates theoperating principle of a double-poppet throttlevalve. c)

The forces exerted on the disks of thedouble-poppet throttle valve resemble atug-of-war. The steam pushes down on top ofone disk and up on the bottom of the otherdisk. Like the rope in the tug-of-war game, thestem keeps the disks in the same position,relative to each other.

RELIEF VALVES

'Relief valves are installed in the steam,water, air, and oil lines, and on various units ofmachinery aboard ship. They open

Chapter 10PUMPS,

automatically when the pressure within the linebecomesteo high. Relief valves protect pipingmuch e same as fuses protect .electricalequipment and wiring in the home. There aiemany types of relief valves. Most relief valveshave either a disk or a steel ball acting against acoil spring.

The disk-type relief valve in figure 10 -21 Aconsists of a valve body, a valve disk, and a stem.The steel spring pushes down .on the disk andkeeps the valve closed. The force of the spririg isgeperally adjustefl, by setting an adjusting nut onto of the spring! The inlet side of the valve isconnected to the system to be protected.

When the force on the bottom of the disk,exerted by the pressure of the fluid in the line,becomes greater than the compression of thespring, the disk is pushed off the seat, openingthe valve. The valve outlet may be opened t6,theatmosphere in compressed air or steam lines.When the valve is used to protect a pump, itsoutlet is connected to the suction line leading tothe pump;. the excess fluid passes through therelief valve, and back to the inlet side of thepump.

The ball-type relief valve shown in figure10-21B operates on the same principle as thdisk valve. The ball valve is generally usedlube oil lines. The operating pressure is regulatedby adjusting the threaded plug (not illustrated)which holds the spring in

BOTTOM SURPACeAReA 20 SO. IN.

600 PSIPanama'

,ARE 10 SC). IN.

JFigure 10-20.Oporating principleof a

douhio-poppot throttio valve.

NISA11610 MN MN

Figure 10-21.Roliof valvoo.

REDUCING VALVES

O

139.41

The heating system and the galley operateon low-pressure steam. The source of..steam forthese systems is the boilers, whin are underhigh pressures. Reducing valves are installed inthe steam lines to these systems, to reduce thepre ure. These valves will hold a constantpr ssure in the delivery lines, even if the boilerp ssure varies over a wide range.

Most reducing valves depend on a balancebe een the outlet or operating pressure and thepre ure of a spring or compressed air in a sealedchat ber. Although some of these valves arequi complicated, the principle on which they

rate is easily understood.The simplified reducing valve In figure 10-22

has a main valve, a piston, and a spring. The

HIGH LOWPRESSURE PRESSURE SPRING

VALVE PISTON

139.40 139.42Figure 10-22.Tho operating principle of a simple

reducing valve.13913.3

FIREMAN

compression of the spring pushes the piston tothe left and opens the valve. When the steam isturn.1 on, it passes through the open valve andbuilds up pressure in the outlet chamber.Whenever the force exerted on the pistonbecomes greater than the force exerted by thespring, the piston moves to the right and closesthe valvt

During the operation, the outlet steampressure and spring force remain in balance withthe valve partly open. Any slight variation inoutlet pressure will upset this balance. Thepiston will move and increase or decrease thesize of the valve opening and restore the originaloutlet pressure.

In some valves the spring is replaced by asealed chamber which contains compressed air.The air pressure acts on a diaphragm instead ofon a piston. The valve can be set to maintain anydesired pressure by adjusting the air pressure inthe sealed chambej. Sometimes the diaphragm islocated between two chambers: one of themopened to the inlet, and the other opened to theoutlet steam. The action of the diaphragmoperates a valve which in turn regulates thesteam pressure on a piston connected to themain valve. In all reducing valves, the outletpressure controls the rate at which the inletsteam is permitted to pass through the valve.

SAFETY VALVES

Each boiler is fitted with safety valves whichallow steam to escape from the boiler when thepressure rises above specified limits. Thecapacity of the safety valves installed on a boilermust be great enough to reduce the steam drumpressure to a specified safe point when the boileris being operated at maximum firing rate with allsteam stop valves completely closed. Safetyvalves are installed-on the steam Mini and at thesuperheater outlet.

Several different types of safky valves areused on naval boilers, but all' are designed toopen completely (POF when a specifiedpiessure is reached and to remain open until aspecified pressure drop" (BLOWDOWN) hasoccurred. Safety valves must close tightly

wilCut chattering and must remain tightlyclosed after seating.

It is important that you understand- thedifference between boiler safety valves andordinary relief 'valves. The amount of pressurerequired to lift a relief valve increases as thevalve lifts, because the resistance of the springincreases in proportion to the amount ofcompression. Therefore, a relief valve opens c;31slightly at a specified pressure, discharges a smallamount of fluid, and closes at a lower pressurewhich is very close to the pressure that caused itto open.

Can you see why relief valves will not do fbrboilers? If the valves were set to lift at anythingclose to boiler pressure, tbe valves would beconstantly opening and closing, pounding thescats and disks and causing early failure of thevalves. Furthermore, relief valves will not rapidlydischarge 'the large amount of steam that mustbe discharged q4ickly to bring the boilerpressure down to a safe point. Relief valvesreseat very soon after they are opened.. (Figure10-23 shows a typical safety valve.)

PIPING

Piping is used throughout the engineeringspaces. One. piping system carries fuel from theservice tanks to the furnace. A second pipingsystem supplies the boiler with feedwater. Athird piping system carries steam from the boilerto the engines and other points where it isneeded. Still other systems are used aboard shipto carry salt water, fresh water, gasoline,compressed air, and certain gases.1,The nature ofthe substances carried in the pipes, as well as thenature of the services performed, makes itnecessary to use a variety of materials, sizes, anddesigns of piping and attached fittings.

PIPING DEFINITIONS

In routine operations aboard ship, there isfrequent misuse of the terms pipe, tubing, andpiping by strikers and inexperienced navalpersonnel. As a step toward correcting themisuse of these time terms, the following.definitions are offered.

..140 6

(N.

Chapter 10-PUIVI S, VALVES, AND PIPING

HAND LIFTING LEVER

SPINDLE

SPINDLE LOCK CLIP

ADJUSTING NUT

ADJUSTING RINGSET SCREW

' ADJUSTING RING

DISK INSERT

DISKCOTTER PIN

DISKHOLDER

NOZZLE RING

Figure 10-23.Steam drum safety valve (nozzle reaction type).

1. A PIPE is made of meal such as castiron, wrought iron, steel, copper, or bra*. Thesize of a pipe is designated by its nominal insidediameter (ID) in accordance with standard ironpipe size (IPS), expressed in inches or fractionsof an inch from 1/8 inch to 12 inches. Pipe isdesignated in three grades or weights of wallthickness as standard, extra strong, or double

135

29.210

extra strong. The outside diameter (OD) is thesame for each of the three wall thicknesses elf*any pipe with a given IPS dimension, whileactual ID of these three pipes will differ. If theID measures more than )2 inches, the pipe isdesignated by its OD.

For example, a 1-inch standard pipe willhave an ID slightly over 1 inc ile 1-inch

141

FIREMAN.

extra strong and 1-inch double extra strongpipes will have lesser ID's because of theirgreater wall thicknesses. An identical ODpermits standardization in pipe dies and taps.

2. TUBING, unlike pipe, is designated forsize. by its nominal OD dimension; specified forwall thickness in decimals of an inch; and joinedby such methods as flanging, welding, soldering,or brazing. Because it has thinner wallg, tubing ismuch more flexible than the thicker-walled pipe.Refrigeration piping systems are examples ofshipboard use of tubing.

3. PIPING is an assembly of pipes ortubing, and fittings, forming a whole orcomposite part of a system designed to transferfluids (water, steamas, and oil).*

PIPING MATERIALS

Most of the piping systems aboard ship aremade of steel, copper, brass, or a copper-nickelalloy. Steer is used for the steam and fuel oillines. Copper tubing may be used for piping thatcarries fresh water, lube oil, and other materials.Nickel-alloy tubing has exceptional resistance tocorrosion, and is used when resistance tocorrosion is an important consideration, such asin salt water and fresh water lines.

You will often hear the term "alloy" used inconnection with various kinds of metals. Ametal is said to be an alloy 1when it containsother metals in addition to the p1 rincipal one.

A chrome-nickel-steel alloy is made byadding chromium and nickel to the molten-steelwhile it is being manufactured. A commonstainless steel used aboard ship, which is a steelalloy, contains chromium and nickel. The alloysof steel, aluminum, and copper are widely usedthroughout the Navy.

.The piping materials must be carefullyselected from specified standards approved byNAVSHIPS; not according to appearance. Forexample, the 7-inch steel tubing employed fortransferring 400 psi, 650°F steam may look thesame to you as the 7-inch steel tubing employed

for transferring 600 psi, 850°F steam. Thematerial of the first may be carbon steel;whereas that of the second MUST bemolybdenum alloy steel, capable of resistinghigh temperature and pressure.

PIPE FITTINGS

A piping system can be made up by joiningindividtal lengths of pipe with unions,couplings, elbows, or other threaded fittings.Piping systems may also be made up by boltedflanges, weldings, _solderings, or by flared .couplings.

The water pipes in a home and some of thelow-pressure pipes aboard ship are fastenedtogether' by THREADED fittings. StandardtreadV pipe fittings are shown in figure 10-24.

142

1i310XFigure 10-24.Standard threaded pip fittings.

Chapter 10PUMPS, VALVES, AND PIPING

139.43Figure 10-25.Gasket insertion..

In high-pressure steam lines the lengths ofsteel pipe are welded together into sections. Aflange is welded to. the ends of the sections. Asuitable gasket is inserted betweetk flanges, andthey are drawn tightly together 1giNtud boltswhich pass through the holes in the outer edgesof the connection. (See fig. 10-25.) Tubing isusually connected by flared couplings (fig.10-26) or by soldering.

GASKETS AND PACKING

When leakage occurs in a piping system, itusually , occurs at one of the joints. Manymethods and materials are used to keep jointsfrom leaking. Flanged joints in piping systemsare made up with gaSkets to make a tight sealand thus to prevent leakage. (When the couplingis tightened, the gasket is compresSed and sealsthe joints.) Figure 10-27 illustrates various typesof gaskets. Corinections in which there aresliding or rotating parts require packing materialto seal the joints.

Figure 10-28 illustrates several kinds ofpacking. It is important that the proper gasketor packing material be used in each application.NavShips Technical Manual, chapter 9950, and

137

other NotySeas publications contain informationon gaskets and packings. Aboard ship, tableswhich show the types of gasket and packingmaterials approved for various services areposted in the engineering spaces.

Materials used for gaskets include pressedcork, asbestos, soft iron, Monel, metallic cloth,and hard fiber sheets. The type of gasket to beused depends on the pressures and temperaturesto-which it will be subjected and in some cases,on the nature of the fluid being carried in thepiping system.

Packing is used to seal the area. around valvestems, revolving shafts, and sliding shafts. Theseunits are designed with a space, known as astuffing box, which surrounds the shaft or stem.When the packing has been placed in the stuffirgbox, it is compressed by tightening a gland ornut which screws up against it. Such anarrangement can be seen if you take an ordinarywater faucet apart. The packing serves to keepthe water from flowing up around the valvestem.

Packing materials in common use includewoven asbestos and rubber; antifriction metalwoven with cotton thread and graphite; spunyarn; and soft metal, flax, and rayoncombinations. The-.type of packing to be useddepends on the service requirements.

STRAINERS

Strainers (fig. 10-29) are installed in almostall piping livErS to prevent the passage of foreign

Figure 10-26.Tee for flared tubing.

C

11.310

FIREMAN

(a) SINGLE-PLATE TYPE

(11) EXPANDING (DOUBLE-PLATE) TYPE

B

FLAT RING GASKET

FIAT FULL-FACE GASKET

INSTALLATION CENTERING RING

CENTERING RING

a

D TYPICAL GASKET CROSS-SECTION

Figure 10-27.Fixed joint gaskets: A. Sheet asbestos gaskets. B. Plain-faced metal gaskets.C. Serrated-faced metal gaskets. D. Spiral-wound, metal asbestos gaskets.

138

.- 144

Chapter 10PUYPS, VALVES, AND PIPING

BRAIDED FLAX

RUBBER -CO RED, DUek - WRAPPED,GRAPHITE LUBRICATED

RINGS

BRAIDED COPPER

COILS

HIGH PRESSURE ROD GRAPHITE.LUBRICATED ASBESTOS

ASBESTOS CLOTH AND RESILIENT RUBBER

MOLD EDRINGS

PRESSED COTTON FABRIC

WIRE-INSERTED ASBESTOS

ASBESTOS, ALUMINUM,GRAPHITE ANDNEOPRENE COMPOUNDS .

EXPANSION JOINT PACKINGS

WIRE- INSERTED BRAIDED ASBESTOS,GRAPHITE- LUBRICATED

Figure 10-28 Type of packing.

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11.325DFigure 10-30.A mechanical steam trap.

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VOLATILE LIQUID

SEAT BUSHING

REPLACEABLE

HERMETICALLY

SEALED BELLOWS 4" 4(a) TRAP COLD; VALVE OPEN (b) TRAP HOT; VALVE CLOSED

a valve and some device or arrangement whichwill cause the valve to open or Close, whennecessary, to drain the condensate from the linewithout allowing the escape of steam. Steamtraps are installed at the low point of a system'or below a machinery unit that has "'to bedrained. Drains are used to remove condensatewhile steam lines and steam-driven machineryare being warmed up. A drain usually consists ofa section of piping and one or diore valves.

There are several types of steam traps in useon naval ships: mechanical (fig. 10-30),thermostatic (fig. 10-31), and impulse (fig.10-32).

You will find additional information onsteam traps in chapter 9480 of NavShipsTechnical Manual.

0--VAPOR

VOLATILE LIQUID

11.326XFigure 10-31.Thermostatic steam trap.

1 4 7141

a

FIREMAN

INLET

LOCK NUT

CYLINDERCIRCULAR

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CYLINDER STEM

CONTROLORIFICE

ALVESEAT

TO HIGH PRESSUREDRAIN SYSTEM

STRAINER

rr

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CIRCULARBAFFLE

VALVESEAT

Figure 10-32.Impulse steam trap.

142

'148

CONTROLORIFICE

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0

CHAPTER '1 1

SHIPBOARD ELECTRICAL EQUIPMENT

Much auxiliary machinery and equipmentaboard modem naval ships is run by--erdchiccity.Regardless of rate or rating, all personnelassigned to a ship will operate some electricdevice in / performance of his duties. As aFireman, you will probably use or operateportable lights, electric drills and grinders,electric heaters,.....rittilatIon blowers and fans,electric-driven pumpk, and other electricalequipment. Therefore, you should know andobserve ,all applicable safety precautions whenworking with or around electrical appliances andequipment.

We will not discuss the theories of basicelectricity in detail in this chapter. However, wewill familiarize you with the different electricalequipment aboard ship and with wliat theequipment is designed to do.

You will find additional information on thebasic principles of electricity in the Navytraining manual Basic Electricity, NAVEDTRA10086-B.

INTRODUCTION TOELECTRICITY

Various techniques and equipment whichapply principles of electricity require that youhave some degree of theoretical knowledge, aswell as practical experience and skill, to operatethem safely.

Electric cables carry the electric energyproduced by the generators to the electricmotors where it is expended in performingwork.

All materials will conduct electricity, butsome of them offer more resistance than others.Metals such as silver, copper, aluminum, and

143

irpn, offer little resistance and are calledCONDUCTORS.

In contrast to gopd conductors, somesubstances, such as wood, paper, porcelain;rubber, mica, and plastics offer a high resistanceto -"an electric current and are known asINSULATORS. Electric circuits throughout theship Ware made up of copper wires covered withrubber or scune other insulator. The wire offerslittle resistance to the current, while theinsulation keeps the current from passing to thesteel structure of the ship.

Definite units have been established tomeasure electrical properties of conductors andcharacteristics of electric currents. A briefreview of these fundamentals of electricity isgiven in the sections which follow.

ELECTRIC CURRENT

Current the rate at which electricity flocsthrough a and 6 ircuit, The practicalunit, called the 'ERE (I) specifies the rate atwhich the electric urrent is flowing. AMPEREis a measure of th intensity or the number ofelectrons passing a point in as circuit eachsecond. The flow of current can be compared tothe flow of water through a pipe.

ELECTROMOTIVE FORCE

Before an electric current can flow through awire, there must be a source of- electric"pressure" just as there must be a pump to buildup water pressure before the water will flowthrough a pipe. This electric pressure is knownas ELECTROMOTIVE FORCE (emf) or voltage(E); the source may be a GENERATOR or aBATTERY.

149)

FIREMAN

If you increase the pressure on the electronsin the conductor, a greater current will flow, justas an increased pressure on water in pipe willincrease the flow.

RESISTANCE

Electrical resistance (R) is that quality of anelectric circuit that opposes the flow of currentthrough it. The unit of resistance is known asthe OHM.

WATT

Power (P) is the rate of doing work. In adirect-current (d-c) circuit, power is equal to theproduct of the current times the voltage, orP = E X I. The practical unit of power is theWATT, or KILOWATT (watts ÷ 1000).

GENERATOR TYPESAND DRIVES'

The generator is the heart of the ship'selectrical system. A large amount of electricity isrequired aboard any ship for die properprovision of air, water, and food.Communications between the various parts of aship depend largely upon the availability ofelectric power to operate the ship's announcingsystem, radio, radar, and lighting systems, aswell as the training and firing of guns.

Since a generator runs at greatest efficiencywhen generating or producing its full-ratedpower output; it is not practicable to have onelarge generator running constantly at part load.Therefore, two or more small generators areinstalled 'aboard ship, depending on the specifictype ship.

Another reason for installing two or mor°generators aboard _ship is to ensure that, in theevent of damage to a generator, there will berough power and lights available until theefective generator has been repaired. In

addition, generators.a installed throughout the-engineering spaces of a s p so that the electricylplant cannot be ,c1Fstroye y ones or two enemyshells or bomb hits.

Alternating .current (a-c) is used aboard theNavy's combatant ships. The advat4ages of a-cinstallations over d-c are lower cost, smallerunits, and less maintenance.

D-C GENERATORSAND EXCITERS

A d-c generator is a rotating machine whichchanges mechanical energy to electrical energy.The essential parts of a d-c generator are theyoke and field windings which are stationary,and the armature which rotates. IiI a-cgenerators, called alternator, the field rotatesand the armature is stationary. To avoidconfusion, the rotating .iembers of d-cgenerators are 'called ARMA URES, and in a-cgenerators they are called ROTORS.

There is no difference between d-cgenerators and exciters. The exciter Is a' d-cgenerator which supplies direct current for ana-c generator. In the pas d-c ship's servicegenerators were used abo d ship. At present,practically all ships hav 0-volt (60-hertz) a-4ship's service and emergency generators. The d-cgenerators used in Navy installations for ship'sservice, or for exciters, operate att.either 120volts or 240 volts. The amount of power outputdepends on the size a esign of the d-cgenerator.

et. typical d-c generators ilustrated ;if .figure114. The armature is sul'oorted On ballbearings. The field coil wins ngs crea amagnetic. field through which the armaturewindings are rotated to induce a voltage in thearmature windings. The current, 'driven by theinduced voltage, is circulated through thecommutator (on the armature shaft) and carriedby the brushes (which ride on the commutator)to the external circuit. Part of the armature

ent4is forced throufh ,the field winding toincrease and maintain the magnetic fieldstrength.

GENERATORS ,

The general construction a-c generators issomewhat simpler than that of d-c generators.The heavy current on a d-c generator has to passthrough the commutator and brushes. -An a-c

144

- .50, .

chapter 11 SHIPBOARD ELECTRICAL EQUIPMENT'

CAC SC FaraPOD MOUNTING

Pozca

YIELDAND

IC LD COM!

DNUANCIS

ENDDELL

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Figure 11-1,A d-c generator.73.161

jenerator does not have a commutator. The`heavy current on an a-c. generator is tqfken fromthe stationary part or _stator windings. An a-cgenerator has two slip rings which carry arelatively small direct current that is supplied bythe exciter to the d-c winding of the rotor.

An a-c generator, like a d-c generator, hasmagnetic fields and an armature. In a small a-cgenerator the armature revolves, the field. isstationary, and no commutator is required. In alarge a-c generator the field revolves and theirmature is wound on the stationary member, orstator.

The principal advantages of the'evolving-field generators over therevolving-armature generators are that:

1. The load current from the stator isconnected directly to the external circuit

itho t using a commutator.

A exTAYOR

notow

2. Only two slip rings are necessary tosupply excitation to the revolving field.

3. The stator winding is not subjected tomechanical stresses that are due to centrikalforce.

The a-c generators, or alternators, used bythe Navy are divided into two classes: (I)low-speed, engine-driven alternators, and (2)high-speed, turbine-driven alternators.

The high-speed alternator may be eithersteam- or gas-turbine driven.

The low-speed, engine-driven alternator (fig.11-2) has a large °diameter revolving field, withmany poles, and a stationary armature.' Thestator (fig. I1-2A) contains the armaturewindings. The rotor (fig. 11-2B) consists ofsalient, or protruding, pales on which ,aremounted the d-c field windings.

1 The high-speed, turbine-driv alternator(fig. 11-3) is Connected either i ctly orthrough gears to a steam turbine. Th enclosedmetal structure is part of a forced ventilationsystem that carries away the heat by circulation

139.43.0X of air through the stator (fig. 11-3A) and rotor* Figure 11-2.Low-speed engine-driven alternator. (fig. I L-3B).

1454

f.,,

151

SHIP'S SERVICETURBINE- DRIVEN GENERATORS

Ship's service genwtors are so namedbecause they furnish electricity for the service ofthe ship. Aboard most steam-driven ships of theNavy, these generators are driven by turbines.Large ships may have as many as six or eightship's service generators and from one to threeemergency diesel-driven alternators.

New construction destroyers have fourturbine-driven ship's service generators (two in:the forward engineroom and two in the afterengineroom), and two smaller diesel-drivenemergency generators, one forward and one 'aft.

FIREMAN

The type of ship's service generatorcommonly used aboard ships in the Navy is

11

i `A STATOR

noToR'

4. .139.44X4Figure 11-3.High-speed turbine-driven alternator.

illustrated in figure 11-4. Although generatorsets (turbogenerators) may be built differerittball have the same arrangement of major parts.

Turbines used for driving the ship's servicegenerators diffrOrom other auxilial turbines inthat they usually operate on superheated steam.These turbines are usually of the axial-flow,multistage, geared type. The turbine exhausts toa separate auxiliary condenser which has its owncirculating pumps, condensate pumps, and airejectors, Cooling water for the condenser isprovided by the auxiliary circulating pumpthrough separate injection and overboard valves.

Superheated steam, is supplied to the ship'sservice generator turbine from either the mainsteam line or a special turbogenerator line whichleads directly from the boiler. Aboard someships, the turbine mayin the event ofcondenser casualtybe discharged directly tothe atmosphere, or to the main condenser whenthe main plant is in operation.

Because the ship's service generator mustsupply electricity at a constant voltage andfrequency (hertz), the turbine must run at aconstant speed even though the load will varygreatly. Constant speed is maintained by aspeed-regulating governor. This turbine also hasan overspeed trip,, which closes the throttle ifthe turbine overspeeds or if the speed-regulatinggovernor fails to function; - aback- pressure trip,which closes the throttle if excessive exhaustpressure is built up; and a manual trip whichmay be used to close the throttle quickly ifthere is damage to the turbine Or to thegenerator. The shaft glands of the shit* servicegenerator turbine are supplied with gland- sealingsteam; the system is similar to that ased formain propulsion turbines. Other auxiliaryturbides in naval use are ..selcicun,t if ever,

A provided with gland-sealing systems.

146

Z'

DIESEL-DRIVEN GENERATORS

Practically all Navy ships are equipped withdiesel-driven 'emergency generators. Dieselengines, rather than turbines and reductiongears, are most suitable for this applicationbecause of their quick starting ability!Emergency generators furnish power directly to

- 1t 2

Chap er 11 SHIPBOARD ELECTRICAL EQUIPMENT

760 - hW 60-HzGAGE

GENERATORBOARD

GEAR BOX TURBINE

',-THROTTLE

VALE

CONDENSER4

Ficura 11-4.-750-10V Turbine-Generator Sot.

the radio,, radar, gunnery, and vital machineryequipment, through an emergency switchboardand automatic bus transfer equipment.

The typical shipboard plant consists of twodiesel emergency generators, one fo and andone aft, in spaces outside the eng nerooms andfirerooms. Each emergenty generator has itsindividual switchboard and switchingarrangement for control of the generator and fordistribution of power to certain vital auxiliariesand a minimum number of lighting fixtures invital spaces.

The capacity of the emergency unit varies/with the size of the ship on which the unit is

installed. Reprdless of the size of the

47153

139.67

installation, the principle_ of operation is thesame. .

Detailed information concerning theoperation of diesel-driven generators can beobtained from appropriate manufacturers'technical manuals.

SWITCHBOARDS

Switchboards consist of panels for muntingthe various measuring instruments, indicatingdevices, and protective and regulating apparatusrequired to control the operation of thegenerators and the distribution of electric

FIREMAN

00wer. A distribution switchboard is providedfig each generator or group of generators.

Most Navy ships have from two to fourship's service generdtor switchboards; smallships, such as destroyers, have two switchboards,whereas large ships may have as many as four toeight switchboards. In many cases two or moregenerators can feed one switchboard.

Most switchboards have the equipmentgrouped to form a number of units. Each unit iscomplete. Bus bars .are used to tie each unittogether to, form a switchboard. There aregenerator, bus tie, power distribution, andlighting distribution units. Each of thesecomplete units has a separate front panel on theswitchboard. Newer ships, Jhave transformersthroughout the' ship with lighting distributionpanels instead of lighting distribution units. Anumber of these units mounted on a commonbase comprise a section. A switchboard mayconsist of a single section or 'of several sections,each complete in itself but connected by cablesto form a switch-gear group. This arrangementof several,§m41 sections lessens the danger ofshock, localiiti damage from fire, and providesfor easy removal of damaged sections for repairsor replacement.

The two types of switchboard constructionare live front and dead front. The live frontswitchboard is found only on very old shipswhere low-voltage and d-c distribution systemsare used, and as interior 'communicationsswitchboards. The more cdmmon switchboard,shown in figure 11-5, is used for all a-cdistribution systems.

(NOTE: The terminals are accessible on the livefront type. In, the dead front switchboard, themeters and operating handles are mounted .onthe panels, and all live parts are located withinthe panels.)

GENER,ATOR ANDDISTRIBUTION SWITCHBOARDS";

Ship's service 450-volt, a-c switchboards areall of the dead front type. These switchkeprdsare built to provide efficient and safe operation

148

- 15 4

of the electrical system. A typical powerdistribution system in a destroyer consists offotrr generatorstwo forward and two aft andtwo distribution switchboards, one with eachtwo generators. All the necessary apparatus forcontrolling each generator and for distributingits power is incorporated in its associatedswitchboard.

The forward ship's service generators anddistribution switchboard are the controlswitchboard. It is provided with instruments andcontrols for the after generators. TheseInstruments and controls are necessary too

parallel the generators and equalize the load. AnAutomatic voltage regulator is mounted on eachswitch4oard to control the generator fieldexcitation and to maintain a constant a-cgenerator voltage throughout the normalchanges in load.

Two emergency diesel generator sets provideelectric power for limited lighting and for vitalauxiliaries in the event of failure of the ship'sservice power. One unit is located in the forwardemergency generator room and the other unit islocated in the after emergency generator room.The forward emergency switchboard is normallyenergized from the forward ship's serviceswitchboard, and the after emergencyswitchboard is energized from the after ship'sservice switchboard during normal operation.

D-c power distribution systems are in use onsome older ships that have large deck machineryloads. Th, se systems, which consist of the ship'sservice gene and distributiontchboards,are similar to the a-c systems. On new ships, d-cpower is provided at the load with. rectifierswhen:required.

COMPONENTS, OFA SWITCHBOARD..

Each switchboard includes one or moreunits, a bus tie unit, a poWer distribution unit;lighting distribution units Or transformers, andlighting 'distribution panels. Large circuitbreakers connect ship's service and emergencygenerators to th power distribution system.

-as 1

Chapter 11$H1PBOARD ELECTRICAL EQUIPMENT

They are also used on bus ties and shoreconnection circuits. In accordance with theelectric load, smaller circuit breakers are alsoinstalled on switchboards and on distributionpanels throughout the ship.

Circuit Breakers

Circuit breakers (fig. 11-6) equipped' withindividual automatic tripping devices are used to

isolate faulty circuits and to serve as overloadprotection. These circuit breakers are a part o(the switchboard equipment. Circuit breakers;rather than fuses, are used in circuits thatrequire large amounts of current. They can bt)operated for an indefinite period, and theIaction can be controlled with greater accuracy'

Overload circuit breakers open automaticallywhen the current (load) on the circuit exceeds apreset value for which the circuit breaker is set.

77.254Figure 11-5.Ship's service switchgear group No 15 section 1513.

149

155

FIREMAN

4 31. OPERATING HANDLE CHOWN 4. COVER SCREWS

IN LATCHED POSITION C.2. AMPERE RATING MARKER 5. BREAKER NAMEPLATE

3. MOUNTING SCREWS G. COTTER KEY HOLE

77.241Figure 11-6.Circuit breaker.

Circuit breakers used with shipboard equipmentare not susceptible to tripping under successiveheavy shocks, such as those caused by gunfire.Circuit breakers are used on all rotatingelectrical machinery and feeders to vital loads,such as gunmounts and searchlights.

In addition to overload relays, reverse powertrip relays are provided on a-c generator circuitbreakers. These units are designed to open in theevent of a power reversal. The units are mountedwithin the generator switchboard.

Voltage Regulators

Voltage regulators; 'installed on theassociated switchboards, are used for a-c ship'sservice and emergency generators. The voltageregulator maintains the generator voltage withinspecified limits. The switchboard operator car,

adjust (set) the voltage of the generator at anyvalue within nominal limits. When additionalloads are applied on the generator, there will bea tendency for the voltage to drop. Theautomatic regulator keeps the voltage of thegenerator constant at various loads.

Indicating Meters

All -the important switchboards aboard shipare provided with electrical meters of varioustypes. Electrical meters, somewhat like gagesand thermometers, show the operator what istaking place in the electrical machinery andsystems. electrical meters are of two generaltypes: installed meters (on switchboards) andportable meters. Some of the common metersthat are used on switchboards are voltmeters,ammeters, kilowatt meters, and frequencymeters.

150

ELECTRIC ,MOTORS

Electric motors are used aboard ship ,tooperate guns, winches, elevators, compressors,pumps, ventilation systems, and other auxiliarymachinery and equipment. There are manyreasons for using electric motors: they are safe,convenient, easily controlled, and easily suppliedwith power.

A motor changes electrical energy, producedby the generators, into mechanical energy. Thereare gportant reasons for changing mechanicalenergy to electrical energy and back again tomechanical energy. One reason is that electriccables can be led through decks and bulkheadswith less danger to watertight integrity thansteam pipes or mechanical shafts. Anotherreason is that damage to a steam line can causesteam to escape, resulting in personnel injury. Ifan electric cable is used and a fault occurs, thecircuit breaker protecting the cable opensautomatically.

D-C AND A-C MOTORS

The a-c motor, smaller and requiring lessmaintenance than the d-c motor, is extensively

`used by t = Navy. The d-c motor, which is built

Chapter 11SHIPBOARD ELECTRICAL EQUIPMENT

like a d-c generator, is used mostly aboardauxiliary-ships and some small ships.

Most of the a-c motors used aboard ship are3-phase, 60-hertz, 450-volt motors. Titinduction motor is commonly used by the Navy.Although most a-c motors have one speed, anumber of motors with two speeds,those on ventilation systems, are installedaboard ships.

MOTO1 1 CONTROLLERS

Controlling devices are used to start, stop,speed up, or slow down motors. In general, thesecontrollers are standard equipment aboard shipand are either manual, semiautomatic, orautomatic. They are dripproof and shockresistant. In some installations the controllersare operated by remote control, with the switchat a convenient location.

These motor control devices (controllers,master switches, and electric brakes) protect theequipment to which they are connected.Controllers provide protective and governingfeatures for every type of shipboard auxiliary.To govern the controllers themselves, chasterswitches of various types are installed. Electricbrakes are used to bring a load to rest, or to holdit at rest, when electric power to the motor iscut off. Aboard ship, electric brakes are usedprimarily on hoisting and lowering equipmentsuch as cranes, winches, and windlasses.

Most controllers function simply to start orto stop auxiliary machinery, but somecontrollers also provide for reversal of directionor multispeed operation. Motor controllers,some times called starters, have overloadprotective devices to prevent burning out themotor. Most controllers cut out automaticallywhen the electric power fails, and they have tobe restarted manually. .

BATTERIES

Aboard ship, batteries are one of the sourcesof electricity for emergency and portable power.Dry cell batteries are used primarily forflashlights, hand lanterns, and test equipment.

Storage batteries are also used for emergencyequipment aboard ship, for ship's boats, andforklifts. The storage battery is used as a sourceof electrical energy for emergency dieselgenerators, gyrocompasses, and emergencyradio.

Since you may act as a boat engineer, youshould be familiar with safety precautions to beobserved when you work around batteries.Batteries must be protected from salt water,which can mix with the electrolyte (acidsolution) and give off poisonous fumes. Saltwater in the electrolyte also sets up a chemicalreaction which will ruin the battery. If this ever

\ occurs, notify the electric shop immediately.

Storage batteries, whell being charged, giveoff a certain amount of hydrogen gas. Batterycompartments should be well ventilated todischarge this gas to the atmosphere. Flames orsparks of any kind, including lighted cigarettes,should never be allowed in the vicinity of anystorage battery that is being charged. When thebattery is low or does not perform properly, theboat engineer should notify the Electrician'sMate (EM) so that the faulty condition can becorrected promptly.

151

PORTABLE EQUIPMENT

Aboard any ship there will be smallelectric-powered equipment, such as portableelectric drills, hand lanterns, small ventilationblowers, and handtools. SAFETY is wearingrubber gloves and protective safety goggles whenyou work with metal-cased portable electrictools.

BATTLE LANTERNS

Relay-operated hand lanterns (fig. 1 l-7A)usually called battle lanterns, are powered bydry cell batteries. Hand lanterns are provided togive emergency light when the ship's lightingsystems fail. These lanterns are placed in spaceswhere continual illumination is necessary, suchas machinery spaces, control rooms, essentialwatch stations, battle dressing stations, andescape hatches. All auxiliary machinery with

157

FIREMAN a

1-EANTERN(RELAY OPERATED)

D HAND LANTERNI") (MANUAL OPERATED)

C PORTABLE FLOOD LANTERN

7. 77.47'47 Figure 11-7.Special lights.

152

-

Chapter 11-- SHIPBOARD ELECTRICAL EQUIPMENT

gage boards should be provided with a battlelantern to illuminate the gage board in the eventof a casualty. The battle lantern should not beremoved from its mounting bracket except in anemergency. DO NOT use It as a flashlight.

The relay control boxes for battle lanternsare connected to the emergency lighting supplycircuit (or to the ship's service lighting circuit) inwhich the lantern is installed. If power in thecircuit fails, the relay opens and the batterieslight the lantern.

Hand ,(battle) lanterns are capable ofoperating for approximately 10 continuoushours (or the equivalent) before the light outputceases to be useful.

Similar hand lanterns (fig. 11-7B) which areNOT connnected to relays, are installedthroughout the ship to provide illpmination instations which are manned occasionally. TheseLanterns are manually operated. If used in anemergency, the manually operated hand lanternsshould always bp1 RETURNED TO THEIRORIGINAL LOCATION.

SEALED BEAM LIGHTS

Sealed beam lights (fig. 11-7C), a type offlood lantern, are used to give high-intensityillumination in da age control or otherTemergency repair work. These units consist ofasealed beam light similar to that used forautomobiles. The sealed beam light, powered byfour small wet cell storage batteries, is mountedin the battery case and fitted with a handle forconvenience in carrying. A sealed beam lampwill operate for the equivalent of 3 continuoushours before the battery requires recharging.When the battery is at full charge, the beam hasan intensity which is similar to that of theheadlight on an automobile. At the end of 3hours the light, output will gradually drop toabout one-half its original brilliance. Thesesealed beam lights are normally stored in thedamage control repair lockers.

PORTABLE EXTENSION LIGHTS

Portable extension lights are _widely usedaboard ship, especially in the engineering spaces.

Only approved extension lights are to beused. Adequate lighting is necessary when

153

159

maintenance work is being done or whenmachinery repairs are being made.

The portable extension light and cord shouldbe in good condition. The cord should' be freerom cuts or damaged areas. The light and cord

s tuld be free from moisture, oil, and grease.Do not lay extension cords across decks &

other places where they. may be damaged. Ifpossible, cords should be run overhead and tiedin place. Also, keep rubber cords away from hotsteam piping as well as away from oil and paint.Avoid running an extension cord through awatertight hatch or door.

An extension light should be returnedpromptly to the tool issue room or electric shopafter the work for which it Was used has beenfinished. The light should be clean, dry, and ingood condition. Defective extension lights(including lights without guards) should bebrought immediately to the electric shop forrepairs.

PORTABLE TOOLS

Proper care and precautionary measuresshould be taken in handling and working withportable tools such as electric drills and grinders.Protective goggles must ALWAYS be worn whentools such as wire brushes and grinders are used.

There is an inherent danger when you workwith portable electric tools because of thepossibility of electric shock. Electrician's Matesare required to make weekly tests of all portableelectrical tools to ensure .that they are safe touse. Portable tools in use on Navy ships areprovided with a grounded plug and a groundwire connected to the metal part of the tool.Grounded receptacles are installed throughoutthe ship. The cords for portable electric toolscontain three conductors; the third conductor isused to ground the portable tool to the ship.These precautions are taken to preventdangerous electric shock to operators ofportable tools.

SHIPBOARD ELECTRICAL SYSTEMSAND- CONNECTIONS

As a Fireman, you should be familiar withthe power distribution systems, the lighting

FIREMAN

distribution systems, and shore powerconnections which have been described brieflyin this manual. You will find greater detail on.this and other shipboard electrical equipment inchapter 9620, Nav Ships Technical Manual.

POWER DISTRIBUTION SYSTEMS

The power distribution system connects thegenerators, which furnish electric power, to thepower-driven equipment installed throughoutthe ship. From the generator switchboards, a

4., distribution system consisting of feeders, mains,submains, load center panels, and distributionboxes carries power to every part of the ship.The most important auxiliaries are supplied withnormal, alternate, and emergency feeders,through automatic bus transfer units, each witha separate source of power. Casualty powersystems are installed aboard ship to provideelectrical connections when both ship's serviceand emergency electrical systems are damaged.

LIGHTING DISTRIBUTION SYSTEMS

Lighting distribution systems are necessarynot only to light the ship but also to assistpersonnel in controlling damage. Aboardcombatant ships two lighting systems areinstalled: ship's service lighting and emergencylighting. The ship's service lighting normallysupplies all lighting fixtures. Emergency lightingcircuits are supplied to vital machinery spacqs,the radio room, the combat information cente'1,and other vital spaces. The emergency lightingsystem receives power from the ship's servicegenerators but, if normal power is lost, theemergency system is automatically cut in on theemergency generators. Lighting distributionsystems are similar to power distributionsystems, except that they (I) are morenumerous, (2) have lower voltages (120V), and(3) have smaller panels and cables.

Lighting distribution requires a variety ofpanels and distribution boxes to connect theirloads with their power supplies. High-voltagefeeders from switchboards are stepped downfrom 450V to approximately 120V bytransformers which are connected todistribution panels. CircuitA emerging fromdistribution panels are connected to feeder

4

154

160

distribution boxes. The feeder distribution box,which is similar to the power distribution panel,has only a few branch circuits. The distributionboxes carry power directly to. the actual loadcircuits.

SHORE POWER CONNECTIONS

Shore power connections are installed at ornear suitable weather deck locations to whichportable cables from the shore, or from a shipalongside, can be connected. Power Can besupplied through these connections to theswitchboard when ship's service generators arenot in operation.

ELECTRICAL SAFETYPRECAUTIONS

There are certain safety precautions whichshould be observed by those who work with oraround electrical appliances and equipment.

Following are some of the most commonelectrical safety precautions which all shipboardpersonnel are required to follow:

Do not attempt to maintain or repairelectric equipment. Leave the electrical work tothe Electrician's Mates and IC Electricians.

Observe and follow all pertinentinstructions and electric warning signs aboardship.

Observe all safety precautions regardingportable electric lights and tools. (Rubber glovesand goggles.)

Ren) ember that 120-volt electricity isvery dangerous, especially aboard ship.

Do not touch or operate an electricalswitch which has a warning tag attached to it.

Do not go behind electricalswitchboards.

Do not touch live electric wires andfittings.

Do not remove steamtight globes fromlighting fixtures.

Chapter 11SHIPBOARD ELECTRICAL EQUIPMENT

Do not remove battle lanterns &Om theirlocations.

ZDo not use manually operated hand

battle lanterns for unauthorized purposes. Eachperson should have his own flashlight.

Do not use electric cables to hoist orsupport heavy weights, and do not use thewireways for storage.

Do not permit water to get intoelectrical equipment.

Remember that a flame, spark, or lightedcigarette can cause a disastrous batteryexplosion.

Remember that electrolyte from astorage battery can cause severe burns and can

`-damage equipment and clothing.

When you repair equipment that isdriven by a motor, have an electriciandisconnect the circuit and tag it as out ofcommission.

Do not start or operate electricequipment when flammable vapors are present..

Take time to learn the electrical safetyprecautions that are applicable to your assignedduties and duty station, whether it be thefireroom, engineroom, electric shop, or otherduty assignment. (A thorough understanding ofelectrical safety precautions will help preventinjury to yourself and damage to equipmentwhich you may be called upon to operate.

If you are ever in doubt about theoperating condition of electrical equipment,CALL AN ELECTRICIAN.

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CHAPTER 12

INTERNAL COMBUSTION ENGINES

Most of the auxiliary machinery andequipment aboard large Navy ships utilizeelectric motors as prime movers. This chapterdealwrimarily with internal combustion enginesin which a mixture of air and fuel serves as theworking fluid.

Internal combustion engines are usedextensively in the Navy, serving as propulsionunits in a variety of ships and boats. Also,internal combustion engines are used as primemovers, or energizing units, for auxiliarymachinery. In most shipboard installations,internal combustion engines are of theRECIPROCATING type. In relatively recentyears, GAS TURBINE engines have also beenplaced in Navy service as power units. Thediscussion which follows will deal primarily withreciprocating engines.

RECIPROCATING ENGINES0

The internal combustion engines (diesel andgasoline engine) with which you will beworking are machines that convert heat energyinto mechanical energy. Diesel and gasolineengi,pes are of the reciprocating type.

The general trend in Navy service is to installdiesel engines rather than gasoline engines,unless special conditions favor the use ofgaiokine engines. Small boats used inconjunction with airplane facilities arefrequently powered with gasoline enginesbecause the available fuel supply is gasoline. In

!dition, gasoline engines (P-250 pump) are usedlme installations because of their small size

.tck of suitable diesel engines.

.156

t6NITION PRINCIPLES

The gasoline and, diesel engines differprincipally in that the gasoline engine has acarburetor and a spark ignition system. The fueland air for the SPARK IGNITION (GASOLINE)ENGINE is mi in the carburetor. Thismixture is drawn i to the cylinders where it iscompressed and igni an electric spark.

T e CO-11 IGNITION type engineis com only known as a DIESEL ENGIN 'E. Thediese, engine ' takes in atmospheric air,compre ses it, and then injects the fuel into thecylinder The heat generated by compressionignites the ei;.hence, the term "compressionignition" is sed h,-Vdiesel engines.

OPERATING CYCLE

All reciprocal g engines have a definitecycle of operation tomize the fuel, get it intothe cylinders, ignit and burn it, and dispose ofthe gases of combustion. All reciprocatinginternal combustion engines operate on either a2-stroke or a 4-stroke cycle. A stroke is a singleup or down movement of the piston, or thedistance a piston moves between limits of travel,Each piston executes two strokes for eachrevolution of the crankshaft. The number ofpiston strokes occurring during any one series ofoperations (cycle) is limited to either two orfour, depending on the design of the engine.

In 4-STROKE CYCLE engines each pistongoes through for strokes and the crankshaftmakes two revolirtie.ris_to=-compete one cycle.Each piston delivers power during one stroke infour, or each piston makes one power stroke foreach two revolutions of the crankshaft.

12

--Chapter 12INTERNAL COMAUSTION ENGINES

B

54.19Figure 12-1.The 4-stroke diesel cycle.

Let us take one cylinder of a diesel engineand trace its operation through the four strokesthat make up a cycle. (See fig. 12-1.) The engineparts shown in this figure include only acylinder, a crankshaft, a piston and connecting-rod, and the intake and exhaust valves. Tosimplify the diagrams (A through D), thevalve-operating mechanism and the fuel systemhave been omitted.

In part A of figure 12-1 the intake valve isopen and the exhaust valve is closed. The pistonis moving downward and drawing a charge of airinto the cylinder through the open valve. Thisportion of the cycle during which the piston ismoving downward is. called the INTAKESTROKE.

When the crankshaft has rotated to theposition shown in 11 of figure 12-1, the pistonhas moved upward, on the COMPRESSIONSTROKE, almost to the top of the cylinder.Both the intake and exhaust valves are closed

157

during this stroke. The air which entered thecylinder during the intake stroke is compressedinto the small space above the piston. Thevolume of this air may be reduced to less than1/16 of what it was at the beginning of thestroke.

The high pressure, which results from thisgreat. reduction in volume, raises thetemperature of the air far above the ignitionpoint of the oil. When the piston nears the topof the compression stroke, the charge of fuel isforced into the cylinder through the injectionvalve. The air which has been heated bycompression ignites the fuel.

tirN

During the POWER STROKE, indicated in Cof figure 12-1, the inlet and exhaust valves areboth closed. The increase in temperatureresulting from the burning fuel greatly increasesthe pressure on top of the piston. This increasedpressure forces the piston downward and rotatesthe crankshaft. This is the only stroke in whichpower is furnished to the crankshaft by thepiston.

During the EXHAUST STROKE, shown inD of figure 12-1, the exhaust valve is open andthe intake valve remains clesed. The pistonmoves upward, forcing the bailed gases out ofthe combustion chamber through the exhaustvalve. This stroke, which completes the cycle, isfollowed. immediately by the intake stroke ofthe nexi cycle, and the sequence of eventscontinues to repeat itself.

The 4-stroke cycle gasoline engine operateson the same mechanical, or operational, cycle asthe diesel engine. In the gasoline engine, the fueland air are mixed in the carburetor, and themixture is drawn into the cylinders through theintake valve. The fuel-air mixture is ignitednear the top of the compression stroke by an,electric spark which passes between theterminals of the spark plug.

The principal difference in the cycles ofoperation for diesel and gasoline engines involvesthe admission of fuel and air to the cylinder.While this occurs as one event in the operatingcycle of a gasoline engine, it involves two events

163

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-FIREMAN

in diesel engines. There are six main eventstaking place in the diesel cycle of operation(intake of air, Compression of air, injection ,offuel, ignition and combustion of charge,expansion of gases, and removal of burnedgases), and five main events in the cycle of agasoline engine (fuel is not injected in a gasolineengine).

TWO-STROKE CYCLE diesel engines arewidely used by the Navy. The Navy ')uses somegasoline engines that operate on the 2-strokecycle; they are used principally to drive portablepumps/

Every second stroke of a 2-stroke cycleengine is a power stroke. The strokes betweenare compression strokes. The intake and exhaustfundtions take place rapidly near the bottom ofeach power stroke. With this arrangement thereis one power stroke for each revolution of thecrankshaft, or twice as. many as in a 4-strokecycle engine.

The steps in the . operation of a 2-strokecycle engine are shown in figure 12-2. Thecylinder shown ,has an exhaust valve but nointake valve. (Other designs have both intakeand exhaust ports and include no valves.) The airenters the combustion chamber through ports(openings) in the cylinder wall; these ports areuncovered by the piston as it nears the bottomof each stroke.

In A of figure 12-2, the piston is movingupward on the compression stroke. The exhaustvalve and the intake ports are closed, and thepiston is compressing the air trapped in thecombustion chamber. At the toR of the stroke,with the piston in the position shown in B offigure 12-2, fuel is injected (sprayed) into thecylinder and then ignited by the hot compressedair.

In C of figure 12-2,\the piston is movingdownward on the power stroke. The exhaustvalve is still closed an the increased pressure,resulting from the bumikg fuel, forces the pistondownward and rotates the crankshaft.

As the piston nears the bottom of the powerstroke, shown in D of figure 12-2, the exhaustvalve opens and the piston continues downwardto uncover the intake ports. Air delivered underpressure by a blower or from the crankcase (in agasoline engine) is forced into the cylinderthrough the intake ports, and the burned gases

158

164

54.20Figure 12-2.The 2-stroke diesel cy

are carried out through the exhaust lve. Thisscavenging operation takes place almostinstantly and corresponds to the intake andexhaust strokes of Ow 4-stroke cycle.

You might expect a .2-stroke cycle engine todevelop twice as much power as a 4-stroke cycleengine; however, it does not because a certainpercentage of the engine's power is required todrive the blower. Nevertheless, 2-stroke cyclediesel engines give excellent service. Smallgasoline engines operating on the 2-stroke cycleprinciple operate satisfactorily, but the largersizes are less popular.

DIESEL ENGINES

The diesel engines used in small boats lookvery much like the gasoline engines used in anautomobile. Each cylinder has an injector to

Chapter 12INTERNAL COMBUSTION ENGINES

admit fuel to the cylinder at the proper time.The injector may also serve as the higl&pressurepump. Some engines have a high pressure pumpwith a hydraulic head which resembles adistributor. The lines carry the high pressure fuelto the injector in the same order Ss the firingorder. On the gasoline e gine, the carburetorprovides the proper mixtt e of gasoline and airfor the cylinder. In most f the 1-cycle.gasoline'engines in use by the Na , the oil is mixed withthe gas to provide lubrication for the beaazkikpistons. Most boat engines ha ,eta sheat exchanger instead of thecoradiator. Although different makes aof diesels vary widely, they all haveessential parts.

POWER SYSTEM

gswater

entionalmodels

he samek

sleeve called a cylinder liner. The upper end ofthe cylinder is covered by a cylinder head.

The pistons are connected to the crankshaftby connecting rods, which transmit power fromthe pistons to the ,crankshaft and convert theirreciprogating motion to the rotary motion ofthe pfankshaft. The rods are joined to the

ns by piston pins (wrist pins) and arenected to the crankshaft by connecting rod

arings. (See fig. 12-3.) Rings on each pistonovide a seal between the Pigton- and the

c linder wall. As the piston moves up and down,rings press' against the cylinder wall, thus

pr venting the air or gases from passing downi to the crankcase or the oil in the crankcaserom working up past the rings. In addition' to

the pressure of 'the rings, compression andcorcibustion pressure between the ring andpiston push the rings against the cylinder wall.

The rotating force of the crankshaft-' is usedto drive such items as reduction gears, propellershafts, generators, and pumps. During three ofthe strokes of a 4-stroke cycle engine, the rotarymotion bf the crankshaft is moving the pistonup and down A. -

The main working parts of the enginetransmit power from the cylinders to thedriveshaft. These ,parts include the cylinders,pistons, connecting rod, and the crankshaft. Thecylinders of most marine engines are containedin a single block or crankcase of iron. Eachcylinder is lined with a special hardened steel

CONNECT 1NGROD BEARING CAP

en

0-

n02

CONNECTING ROD

CONNECTINGROD j3OLTS

OIL SEAL SADDLE

SADDLE SPRING

PISTON PIN CAP

WAS HE

PISTON PIN

CONNECTING RODPISTON PIN

BUNING

PISTON 1

COMPRESSIONPISTON RINGS,

PISTON PIN

of,

OIL CONTROLPISTON RINGS

Figdre 12-3.Piston and conreting rod parts.

159

165

PISTON PIN CAP

76.69

sd

1

FIREMAN

VALVE MECH IISM

The valves are opened by the action of acamshaft, driven by the crankshaft through atrain of gears, or a gear and chain-drivemechanism. The camshaft extends the length ofthe engine and carries one or more cams for eachcylinder. The shaft is cylindrical withirregular-shaped cams. Each cam is circular onone end and has a LOBE (NOSE) on the otherend which gives that end an egg-shapedappearance as shown in figure 12-4B. Thecircular part of the cam is called the cam flat orbase circle.

The camshaft gives an intermittentreciprocating motion as it rotates. A, camfollower br roller,, riding on the rotating cant, islifted each' time the lobe or cam nose comesaround.

The valve mechanism of a 2-stroke cyclediesel engine is shown in the cutaway views thatappear in figure 12-4. This engine has twoexhaust valves which are opened at the sametime by the action of a single cam. They make a

JCA ND. At. tn.., A Al 40.01 ttttt

(Dv. 40Ca.1 .01

A

, 139.46Figgre 124:--Cutaway of a cylinder head, shovving the

valve-operating mechanism.

9

tight fit in the exhaust openings (ports) in thecylinder head and are held in the closed positionby the compression of the valve springs. Therocker arm and tuidge transmit the reciprocatingmotions of the cam roller-to the valves.

. In figure 12-4A the cam roller is riding onthe base circle of the cam and the valves areclosed. As the camshaft rotates, the cam lobe ornose rides under the roller and raises It to theposition shown in figure 12-4B. When the rolleris lifted, the arm rotates around the rocker shaftand the opposite end of the arm is lowenbd. Thisaction pushes the bridge and valves down againstthe pressure of the valve springs and opens thevalve passagfs.

On some types of engines, the camshaft islocated near the crankshaft. In these designs theaction of the cam roller is transmitted to therocker arm by a push rod. In some engines, thevalves are inverted and are located in recesses atthe side of the cylinders. In this arrangement thevalve stems may ride directly on the cams, orthey rimy be separated by a short steel shaft androller called'a tappet assembly.

The camshaft must _be timed with thecrankshaft so that the lobes will open the valvesin each cylinder at the correct instant in theoperating cyeI In the 2-stroke cycle theexhaust valves are opened for only a short timenear the bottom of the power stroke to Rermitthe burned gases to ekape. Since the-.c cle iscompleted in one revolution, the camshaftrotates at the same speed as the crankshaft.

160

166

The 4-stroke cycle engine has an intake andan exhaust valve in every cylinder.-Each valve isoperated by a separate cam. The intake valve isheld opeh 'during the intake stroke, and theexhaust valve is opened during the exhauststroke. Since two revolutions of the crankshaftare necessary to complete a 4-stroke cycle, the.camshaft of these engines turns only half as fastas the crankshaft

AIR SYSTEM

In "the 4-stroke. cytte en ne, the air entersthe cylinders through. the i ake valve. As each

Chapter 12INTERNAL COMBUSTION ENGINES

pis* ton* moves downward on the intake stroke,the volume in the combustion chamber increasesand the pressure decreases. The normalatmospheric pressure then forces the air into thecylinder through the intake valve.

Since the 2-strode cycle engine does not gothrough an intake stroke, a means must be...provided to force air into the cylinders. The, airenters through intake ports, uncovered when thepiston approaches the bottom of the powerstroke. (See fig. 12-S.) Since the exhaust valvesare open when the intake ports are beinguncovered, the incoming air forces the burnedgases out through the exhaust valves and fills thecylinder with a supply of fresh air.

On the compression stroke, the exhaustvalves are closed, the intake ports are covered,and the air is trapped in the cylinder. The risingpiston compresses the air and raises itstemperature. By the time the piston reaches thetop of the stroke, the volume of the combustionchamber has been greatly reduced. The relationbetween the volume of the cylinder with thepiston at the bottom of its stroke and thecylinder volume with the piston at the top of its

*

111=611.1111111111* a_ I

75.151Figure 12-5.ml-A 2:stroko-cyclo engine cylinder with

the piston at the bottom all the power stroke.

stroke is called the COMPRESSION RATIO.Compressing the air to 1/16 of its originalvolume would represent a compression ratio of16 to 1.

As the compression ratio is increased, thetemperature of the air in the cylinder increases.Current gasoline engines operate at compressionratios between 8 to 1 and 11 to 1, butcompression ratios of diesel engines rangebetween 12 to I and 16 to 1. This means that onthe compression stroke of a diesel engine the airis compressed to a range of 400 to 600 psi;which results in a temperature ranging from700° to 800° F. However, when2the fuel isinjected Into the cylinder and begins to, burn,the pressure may increase to more than 1500 psiand the temperature may rise as high as 1800°F.

FUEL SYSTEM

The fuel system of the diesel engine drawsfuel oil from the service tank and injects it intothe engine cylinders. Figure 12-6 shows the unitsfound in a typical fuel system of the unitinjector type. The fuel pump draws the fuel oilfrom the tank through a primary filter anddelivers it under low pressure to the injector byway of the secondary- filter. The injector,operated by a rocker arm, meters, pressurizes,and atomizes the fuel as it is injected into thecombustion chamber. The outlet line carries theexcess fuel oll-from the injector back to the fueltank. In some installations, a transfer pump isinstalled between 'the tank and the primaryfilter. In other installations, the injection pumpand injection nozzles are separate units insteadof a combined unit, as shown in figure 12-6.

A diesel engine will not operate efficientlyunless clean fuel is delivered to the injector orinjection nozzles. As the fuel oil is pumped intothe fuel tanks, it is strained through a fine meshscreen. The larger particles of the solidssuspended in the fuel are trapped in the primary

*screen. The secondary filter separates the finerparticles of foreign matter wftich pass throughthe primary filter screen. The final filtering takesplace within the injector. Most filters have wLiain plug for removing the water, sludge, andother foreign matter. The filter should bedrained once each 'day.

161

167

0

FIREMAN

CRIVT PR

PR to. vTO mar RAPIPaD

tPl PIPS

auer01.0

ISCONORAY

PAL PPP

PIPS. 111uRT MP.*WIWI, 10 PUP,

PRUARIP PUP.PM VON ISPIR181)

PUP. ?ANN

2.67XFigure 12-6.The fuel supply system of a General

Motors portable diesel engine.

There are many methods of fuel injection.and just as many types of injection pumps andnozzles. The unit injector shown in figure 12-6consists basically of a small cylinder and aplunger, and extends through the cylinder headto the combustion chamber. A cam, located onthe camshaft adjacent to the cam that operatesthe exhaust valves, acts through a rocker armand depresses the plunger at the correct instantin the operating cycle.

When the injector plunger is depressed, afine spray of fuel is discharged into the cylinder,through small holes in the nozzle. The amountof fuel injected on each stroke of small boatengine fuel pumps is very small. The smoothoperation of the engine depends to a largeextent on the accuracy with which the plungers

inject the same amount .4 fuel into everycylinder.

The an-TOT\I t of fuel injected into thecylinders on each stroke is controlled byrotating the plungers of a unit injector. Thethrottle, which regulates the speed of the engine,is connected to the injectors through a suitablelinkage. A change in the throttle setting rotatesthe plungers and varies the amount of fuelinjected into the cylinders on each stroke.

LUBRICATION SYSTEM

The lubrication system of an internalcombustion engine is very important. If thelubricating system should fail, not only will theengine stop but also many of the parts are likelyto be damaged beyond repair. Therefore, whenlubrication failure occurs, the engine can seldombe run again without a major overhaul.

The lubricating system delivers oil to themoving parts of the engine to reduce frictionand to assist in keeping Them cool. Most dieseland gasoline engines are equipped with apressure lubricating system which delivers theoil under pressure to the bearings and bushingsand also lubricates the gears and cylinder walls.The oil usually reaches the bearings throughpassages drilled in the framework of the engine.The lubricating system of a typical diesel engineis shown in figure 12-7.

Many methqAs of lubleating the individualparts of each type of engine are in use in thedifferent engine models. Generally speaking, theoil is fed from the main gallery throughindividual passages to the main crankshaftbearings and one end of the hollow camshaft.All the other moving parts and bearings arelubricated by oil drawn from these two sources.The cylinder walls and the teeth of many of thegears are lubricated by oil spray thrown off bythe rotating crankshaft. After the oil has servedits purpose, it drains back to the sump to beused again.

'IThe oil pressure in the line leading from thepump to the engine is indicated on a,Bourdon-type pressure gage. A temperature gagein the return line provides an indirect methodfor indicating variations in the temperature o'the engine parts. Any abnormal drop in pressure

,or rise in temperature should _be investigated at

162

168

Chapter 12 INTERNAL COMBUSTION ENGINES

12 0 Ct ti ARM

PUSH ROO

OIL PRessuria ciaGe\

b

C 0 3 0E.. Jai

PISTON PIN

CONNECT= RooU

11.

CAMSHAFT OE AR

THRUST DUTTON 1.3.*V ALVC LIFTER

MAIN OIL LINE

CAMSHAFT

CRANKSHAFT

i±CRANKSHAFT GEAR

OIL PAN

OIL INLET SCREEN

OIL PUMP

OIL INLET SHIELO

.

Figure 12-7.Basic units and oil passages of a pressure feed lubrication system.

once. It is advisable to secure the engine untilthe trouble has been located and corrected.

All of the engine parts are lubricated with oildelivered by the gear-type oil pump. This pumptakes suction through a screen from an oil panor sump. From the pump, the oil is forcedthrough the oil strainer and the oil cooler intothe main oil gallery. This gallery extends thelength of the eeirgirie and serves as a passage andreservoir from which the oil is fed to the mainbearings.

Constant oil pressure, throughout a widerange of engine speeds, is maintained by thepressure relief valve which allows the excess oil

163

OIL LEVEL

29.96

to flow back into the sump. All of the oil fromthe pump passes through the strainer, unless theoil is cold and heavy, or if the strainer (or oilcooler) is clogged. In such cases, the bypass valveis forced Open and the oil flows directly to theengine. Part of the oil fed to the engine isreturned through the filter, which removesflakes of metal, carbon particles, and otherimpurities.

COOLING SYSTEM

Diesel engines are equipped with awater-cooling system to carry away the excess

169

I

FIREMAN

heat produced in e engine cylinders. The wateris circulated thr ugh water jackets in thecylinder walls and passages that surround thevalves in the cylind head. -

Ei erifr-freshiwat r or sea water may be used

wate is circulated t lough the engine and then

for ooling. IV som engines the sea water iscirc dated through the engine and thendisci arged overboar In other types, fresh

through a heat exchanger. Sea water is circulatedthrough this exchanger and cools the freshwater. An advantage of the fresh water system isthat it keeps the water passages cleaner and thusprovides better cooling and allows the engine tooperate at higher temperatures.

NSTARTING SYSTEMS

There are three types of starting systemsused in internal combustion engineselectric,hydraulic, and pneumatic.

As P Fireman you will probably have morec ntact with the electric starting system than

u will with the other two types. Most, if notall, lifeboats aboard ships use an electric starterto start the engine.

_Depending on ship type, the emergencygenerator, whether it be diesel or gas turbine, isstarted by either an electric starter or penumaticstarter. Main propulsion diesels and gas turbinesare usually pneumatic starter systems (air start).

Electric starting systems use direct currentbecause electrical energy in this form can bestored in batteries and drawn upon whenneeded. The bat 's electrical energy can berestored by charging the battery with anengine-driven generator.

The main components of the electric startingsystem are the storage battery, the startingmotor, the generator, and the associated controland protective devices. The storage battery isdescribed in detail in Basic Electricity, NavPers10086-B.

Electric Starting Motors

The starting motor for diesel and gasolineengines operates on the same principle as a

164

110

direct current electric motor. The motor isdesigned to carry extremely heavy loads but,because it draws a high current (300-665amperes), it tends to overheat quickly. To avoidoverheating, NEVER allow the motor to runmore than 30 seconds at a time. Then allow it tocool for 2 or 3 minutes before using it again.

To start a diesel, engine, you must turn itover rapidly to obtain sufficient heat to ignitethe fuel. The starting motor is located near theflywheel, and the drive gear on the starter isarranged so that it can mesh with the teeth onthe flywheel when the starting switch is closed.The drive mechanism must function to (1)transmit the turning power to the engine whenthe starting motor runs, (2) disconnect thestarting motor from the engine immediatelyafter the engine has started, and (3) provide agear reduction ratio between the starting motorand the engine. (The gear ratio between thedriven pinion and the flywheel is usuallvabout15 to 1. This means that the starting motor shaftrotates 15 times as fast as the engine, or-at 1,500rpm, to turn the engine at a speed of 100 rpm.)

The drive mechanism must disengage thepinion from the flywheel immediately after theengine starts. After the engine starts, its speedmay increase rapidly to approximately 1,509-rpm. If the dive pinion remained meshed witthe flywheel and also locked with the shaft ofthe starting motor at a normal engine speed(1,500 rpm), the shaft would be spun at a rapidrate-22,500 to 30,000 rpm. At such speeds, thestarting motor would be badly damaged.

Hydraulic Starting Systetns

There are several types of hydraulic startingsystems in use. In most installations, the systemconsists of a hydraulic starting motor, apiston-type accumulator, a manually-operatedhydraulic pump, an engine-driven hydraulicpumprand a reservoir for the hydraulic fluid.

Hydraulic pressure is obtained in theaccumulator by the manually-operated handpump or from the engine-driven pump when theengine is operating.

When the starting lever is operated, thecontrol valve allows hydraulic oil (underpressure) from the accumulator to pass through

`61

Chapter 12INTERNAL COMBUSTION ENGINES

the hydraulic starting motor, thereby crankingthe engine. When the starting lever is released,spring action disengages the starting pinion andcloses the control valve, stopping the flow ofhydraulic oil from the'accumulator. The starteris protected from the high speeds of the engineby the action of an overrunning clutch.

The hydraulic starting system is used onsome smaller diesel engines. This system can beapplied to most engines now in service withoutmodification other than to the clutch and pinionassembly, which must be changed whenconverting from a left-hand to a right-handrotation..

Air Starting' Systems

Most modern large diesel engines are startedby admitting compressed air into the enginecylinders at a pressure capable of turning overthe engine. The process is continyed until thepistons have built up sufficient compression heatto cause combustion. The pressure used in airstarting systems ranges from 250 to 600 psi.

Some larger engines and several smallerengines are provided with starting motors drivenby air. These motors are similar to those used todrive such equipment as large pneumatic drillsand engine jacking motors. Air starting motorsare usually driven by air pressures ranging from90 to 200 psi.

GASOLINE ENGINES

The main parts of the gasoline engine arequite similar to those of the diesel engine. Thetwo engines differ principally in that thegasoline engine has a carburetor and an electricalignition system.

The induction system ofja gasoline enginedraws gasoline from the f61 tank and air fromthe atmosphere, mixes them, and delivers themixture to the cyl4ders. The induction systemconsists of the fuel tan , the Juel pump, thecarburetor, and the necessary fuel lines and airpassages. Flexible copper tubing' carries the fuelfrom the tank to the carburetor, while theintake manifold carries the fuel-ai mixture fromthere to the individual cylinders. The fuel-airmixture is igted by an electric spark.

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The CARBURETOR is a device used to send I

a fine spray of fuel into a moving stream of airas it moves to the intake valves of the cylinders.The spray is swept along, vaporized, and mixed(as a gas) with the moving air. The carburetor isdesigned to maintain the same mixture ratioover a wide range of engine speeds. TheMIXTURE RATIO is the number of pounds ofair mixed with each pound of gasoline vapor. ARICH MIXTURE is one in which the percentageof gasoline vapor is high, while a LEANMIXTURE contains a low percentage of gasolinevapor.

The electrical system of the gasoline enginehas the same units as the diesel engine, plus theignition system. This system is designed todeliver a spark in the combustion chamber ofeach cylinder at a specific point in thatcylinder's cycle of operation. A typical ignitionsystem includes a storage battery, an ignitioncoil, breaker points, a condenser, a distributor, aspark plug in each cylinder, a switch, and thenecessary wiring.

There are two distinct circuits in the ignitionsystemthe primary and the secondary. Theprimary circuit carries a low-voltage current; thesecondary is a high-voltage circuit. The battery,the ignition switch, the ignition coil, and thebreaker points are connected in the primarycircuit. The seconctiry circuit, also connected tothe ignition coil, includes the distributor and thespark plugs.

The STORAGE BATTERY is usually the 12-and 24-volt type. One terminal is grounded tothe engine frame, while the other is connectedto the ignition system.

The IGNITION COIL is in many respectssimilar to an electromagnet. It consists of aniron core surrounded by the primary andsecondary coils. The primary coil is made up ofa few turns of heavy wire, while the secondarycoil has a great many trims of fine wire. In bothcoils, the wire is insulated, and the coils areentirely separate from each other.

The BREAKER POINTS constitute amechanical switch connected to the primarycircuit. They are opened by a cam which istimed to break the circuit at the exact instant atwhich each cylinder is due to fire. A condensiris connected across the breaker points to preventarcing and to provide a better high-voltage spark.

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FIREMAN

The DISTRIBUTOR, connected to thesecondary or high-voltage circuit, serves as aselector switch which channels electric currentto the individual cylinders. Although the breakerpoints are connected in the primary circuit, theyare often located in the distributor case. Thesame drive shaft operates both the breakerpoints and the distributor.

The SPARK PL11GS, which extend into thecombustion chambers of the cylinders, areconnected by heavy insulated wires to thedistributor. A spark plug consists essentially of ametal shell that screws into the spark plug holein the cylinder, a center electrode embedded in aporcelain cylinder, and a side electrodeconnected to the shell. The side electrode isadjusted so that the space between it and thecenter electrode is approximately 0.025 inch.When the plug Res, an electric spark jumpsacross the gap between the electrodes.

When the engine is running, the electriccurrent in the primary circuit flows from thebattery through the switch, the primary windingin the ignition coil, the breaker points, and thenback to the battery. The high voltage isproduced in the secondary winding in theignition coil and flows through the distributor tothe individual spark plugs and back to theignition coil through the engine frame. It isinteresting to note1fiat The high voltage, whichjumps the gap in the spark plugs, does not comefrom\the battery but is produced in the ignitioncoil.

The ignition coil and the condenser are theonly parts of the ignition system which requii4an explanation. The soft iron core and theprimary winding function as air electromagnet.

e current flowing through the primarywinding magnetizes the core. This same core andthe secondary winding function as atransformer. Variations in the primary currentchange the magnetism of the core which, inturn, produces high voltage in the secondarywinding.

With the engine running and the breakerpoints closed, a low-voltage current flowsthrough the primary circuit. When the breakerpoints open, this current is interrupted; thisproduces a high voltage in the secondary circuit.

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aThe electricity that would otherwise arc acrossthe breaker points, as they are separating, nowflows into the condenser.

The principal purpose of the condenser is toprotect the breaker points from being burned.The condenser also aids in 'obtaining a hotterspark.

The starting system of the gasoline engine isbasically the same as that of the diesel engine.The generator keeps the battery charged andprovides the current to operate the lights andother electrical equipment. The starter motordraws current from the battery and rotates theflywheel and crankshaft for starting. ?

The electrical system usually requires about90 percent of the routine maintenanceperformed on gasoline engines. You should keepthe connections tightened and the batteryterminals covered with a light coating ofpe tro 1 a t um. Unsatisfactory operation canusually be traced to either dirty fuel or fouledspark plugs. If the fuel is strained before it is putin the tank, and if the tank is filled each timethe engine is secured, most of the fueldifficulties will be eliminated. A fouled plug canbe removed and cleaned by wire brushing orsand blasting.

You will find detailed informatiori on sparkignition systems in Engineman 3 & 2, NavPers1054I-B.

GAS TURBINE ENGINES

Until recently, the application of the gasturbine engine to marine use in the Navy hasbeen experimental. Experiments have provedthat the gas turbine engine can be used to powershort-range ships, landing craft, high-speed craftsuch as PT and air-sea rescue boats, emergencygenerators, and portable firefighting equipment.The MSB-5 class minesweepers were the firstU.S. naval ships to use gas turbine engines on anoperational basis. Gas turbine installationsaboard the MSB-5 class minesweepers supplypower for the generators.

In the past few years several classes of shipshave been built, or are under construction,which are totally gas turbine. These ships are ofthe size of the light cruiser and large DLG' class

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Chapter 12INTERNAL COMBUSTION ENGINES

ships. Several other types of ships which are gasturbine-powered are at various stages ofdevelopment.

As service experience has been gained, thenumber of gas turbines in use has increased. Thefollowing discussion deals with a comparison ofgas turbines and reciprocating engines, theadvantages and disadvantages of the gas turbineengines and their principal parts, or components.

COMPARISON OFGAS TURBINES ANDRECIPROCATING ENGINES

The gas turbine is similar to reciprocatingengines in that air is compressed, a fuel-airmixture is burned, and the gases of combustionare expanded to produce useful power. Enginesof the reciprocating type use onecomponentthe cylinderfor compression,combustion, and expansion. Since all threephases take place Within one component, thepower impulse must occur intermittently orperiodically, as the cycle is repeate.. This is nottrue in gas turbine engines; instead, ompression,combustion, and expansion take p ace in threeseparate components. Air is comp essed in onecomponent, combustion takes dace in anadjacent burner, and a turbine for turbines)receives the energy generated by co bustion. Asdoes the piston in a reciprocatin engine, theturbine transmits the energy of th gases to ashaft which drives a useful load. Th three basiccomponents of the gas turbine e a ne are soarranged and connected that the power outputfrom the turbine is steady and co tinuous. Inbrief, the gas turbine engine can be defined as aninternal combustion engine that produces powerby a continuous and self-sustaining process. Anair mass is. compressed and then combined withatomized fuel. The resulting mixture is thenignited and burns. The combustion gas expandsthrough one or more turbines which changesome of the energy into useful power.

ADVANTAGES ANDDISADVANTAGES OFGAS TURBINE ENGINES

In additiod to the development of a uniformflow of power output, gas turbine engines have

several advantages over reciprocating euines.However, there are certain undesirable featuresof gas turbine engines. Not all of the desirable orundesirable features of gas turbine engines arediscussed here, but some of the more importantones are pointed out. The advantages anddisadvantages of the gas turbine engine cannotbe listed in order of importance, because therequirements of the engine as a source of powerdiffer in various applications.

Compared with other types of internalcombustion engines, the gas turbine engineweighs less, takes up less space, and is normallyof simpler design with a smaller _number ofmoving parts. The gas turbine engine developsmore power per unit of weight and unit ofvolume than other engines.

Gas turbine engines start quickly andaccelerate rapidly. Some models can develop fullpower from a cold start in less than one-tenththe time required for a diesel engine in acomparable application. The gas turbine adjuststo varying loads more rapidly than other typeengines.

The number of personnel required tooperate and maintain a gas turbine engine, andthe time required for the training of suchpersonr.e! are much less than for engines ofother types. Only one man is needed to start andoperate some gas turbir4 engines. The simplicityof the operating controls and the automaticsafety devices used reduce the time required fortraining operators.

Compared to a diesel engine, the gas turbinehas far fewer components and produces muchless vibration at full power. The gas turbineengine has a significant advantage over thegasoline engine in the fuel used. The fuel used ingas turbines presents much less fire hazard thanthe highly volatile fuel used in gasoline engines.

Even though the gas turbine engine has someadvantages over other types of internalcombustion engines, it also has sortiedisadvantages, such as a higher r to of fuel

ciland larger componen require

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consumptionfor air inlet and exhaust.

tr.

FIREMAN

COMPONENTS OFGAS TURBINE ENGINES

The gas turbine engine uses processes in itsoperation which-aro similar to those employedin other types ofnternal combustion engines.The engine components and the terms used toidentify them are considerably different fromthe parts and terms which are common to thediesel and gasbline engines. Although gas turbineengines vary in design and Navy installationsinclude engines of other manufacturers, much ofthe discusfion in the following section isapplicable to all gas turbine engines.

The components of a gas turbine engine maybe grouped as (1) parts of the basic engine, (2)engine accessories, and (3) engine systems (fig.12-8).

Parts of theBasic Engine

The forward (compressor end) section of theengine, where a stream of hot expandable gasesis created as a result of continuous compressionand combustion, is called the gas producingsection. This section consists principally of the

STARTER

COMPRESSOR

ATMOSPHERICAIR INTAKE

compressor, combustion chamber (burners), andturbine wheel(s).

The COMPRESSOR is that part of theengine which draws in air and compresses it bycentrifugal force (that force which tends tomove something outward from a center ofrotation). The compressor consists of a rotatingimpeller enclosed by a case. The BURNER isthat part of the engine in which combustionoccurs. It consists of a cylindrical outer shell,perforated inner liner, fuel nozzle, and igniterplug. A NOZZLE is a metal chamber whichcollects combustion gases from the burners anddirects them through fixed vanes or nozzles. TheROTOR is a rotating assembly, consisting ofthe compressor, an interconnecting shaft, andfirst-stage turbine wheel.

The section of the engine which changesenergy into useful power is known as the poweroutput section. The main parts of this sectionare the power turbine wheel, exhaust ducts,reduction gear, and output shaft.

The TURBINE WHEEL is a bladed diskwhich turns when the exhaust gas stream actsupon its blades. A circular metal duct,containing a ring of fixed vanes that formnozzles, which directs the gas flow from the

1

COMBUSTION ICHAMBER

(..

SHAFT TURBINE

PROPULSIONPOWER

COUPLING

-0EXHAUST TOATMOSPHERE

147.135Figure 12-8.Schematic diagram showing relationsh p of parts in single-shaft gas turbine engine.

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Chapter 12INTERNAL COMBUSTION ENGINES

first-stage turbine to the second-stage turbine iscalled the INTERSTAGE NOZZLEASSEMBLY.

Engine Accessories

The main engine components discussed tothis point are not the only components requiredto make a complete engine. Like other types ofinternal combustion engines, the gas turbineengine includes, various accessories.

The pa is which constitute the engineaccessory gr up are driven by the engine rotoror by the output shaft. The rotor-drivenaccessories include the gear-type fuel pump,centrifugal fuel control governor, combinationpressure-scavenge oil pump. A centrifugal.overspeed switch is driven by the output shaft.

Engine Systems

The principal systems of a gas turbine engineare those which supply fuel for combustion, oilfor lubrication, and electricity or air for startingthe engine and for the operation of instrumentsand warning and safety devices.

The engine accessories are usually consideredas components of whichever system they affect.

OPERATION OFSMALL BOAT ENGINES

When a ship is at anchor, the officers andcrew travel to and from the shore in small boats.As a Fireman, you may be assigned as anengineer on one of these small craft. A coxswainwill be in charge of the boat. In some boatsthere may also be two seamen actpg as bow andstern hooks.

You will be responsible for operating theboat's engine. You will receive your orders fromthe coxswain over the boat's bell system. Youshould know the. bell signals; two sounds forneutral, one for slow ahead, three for reverse,and four calls for full speedin the direction inwhich you are going. The coxswain will expectyou to comply with the bells instantly. You willbe required to follow certain safety precautions

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as a boat engineer. Refer to Basic MilitaryRequirements, NavTra 10054-D, chapter 19, foradditional information.

DIESEL - POWEREDBOAT OPERATION

The actual operation of a small boat dieselmight be considered as consisting merely ofstarting it, regulating the speed, and stopping it.However, there are other factors which shouldbe considered. If you are goof to depend on theengine to give reliable service, you must give it alot of attention. Your first experience in havinga casualty halfway between the ship and dockmay leave a lasting impression on you,particularly if you happen to have the captainaboard.

When you are assigned to a boat, your firstresponsibility is to inspect the engine and warmit up. You should check the fuel supply, thelubricating oil, and the cooling system. Whenyou are satisfied that everything is as it shouldbe, you are ready to start the engine.

Starting a diesel engine ordinarily consists ofplacing the throttle in the idle position, oropening it part way, and pressing the starterbutton. The engine should start after the starterhas turned it over a couple of times. It should bewarmed up by running it at low speed until it isup to operating temperature.

While the engine is warming up, you willhave a chance to find out whether it is in goodrunning condition. Watch the instrument panelto help you determine the condition of theengine. (See fig. 12-9.) For example, if the oilgage fails to register any pressure, you shouldstop the engine immediately. The watertemperature gage is used as an indication of thetemperature of the engine parts. The engineexhaust is usually cooled by sea water; the(exhaust discharge should be inspectedimmediately after starting to determine whetherthe water pump has suction. If the pump does,not have suction, stop the engine and check thecooling system for such troubles as a cloggedstrainer and closed sea valves. You should checkthe idling speed by bringing the throttle back tothe idling position. The engine should respond

FIREMAN

0

Figure139.48

12-9.The instrument panel of a smalldiesel-powered boat.

normal'y to changes in the throttle setting, andit should run smoothly after being brought up tooperating temperature.

Yotr should know where the fuel- andlube-oilkrainer drains are located so that youcan get- rid of any water that may accumulate inthese sy4tems. If lube oil must be added, see that

cPf

the proper grade approved for that particularengine is used.

The engine can be stopped by merely closingthe throttle. You 'should leave the enginecompartment clean and orderly. A report callingattention to any abnormal operating conditionthat you may have noticed will be a help to themaintenance and servicing crew.

Another important part of your job isTROUBLESHOpTING. Diesel engine failure'canuscially be attributed either to the fuel system orto improper cooling or lubrication. If the fuel isnot reaching the engine cylinders, you can oftentrace the trouble to an empty fuel tank or anaccumulation of water in the strainers. Aplugged vent in the fuel tank filler cap will causea vacuum to form in the top of the tank, and theengine will stop for lack of fuel. Overheatinggenerally results from a lack of either oil orcooling water.

GASOLINE ENGINEOPERATION (

The operation of a small boat gasolineengine is similar Cothat of a diesel engine. Sincegasoline from a leak or an 'open container willvaporize quickly and may form an explosivemixture, additional precautions against fire mustbe taken. Adequate ventilation must be providedto rid the engine compartment of anycombushble vapors which may accumulate. Nosmoking is permitted in small boats at any time,this is especially important in boats equippedwith gasoline engines.

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CHAPTER 13

ENGINEERING WATCHES

Throughout the chapters of this trainingmanual you have become acquainted with theorganization and ratings of the engineeringdepartment. You may be assigned to one ofmany different types of ships. On these shipsyou will find that the engineering spaces vary insize and appearance. If you are assigned to asteam-driven ship, you may find the boilers, themain engines, and their associated equipment inone space; or you may find the boilers and theirequipment in one space, and the main enginesan d their equipment in another space.Regardless of the number of boilers and mainengines, many of the watches are basically thesame. Therefore, the information in this chapteris general in nature and does not applyspecifically to any one ship.

This cha ter contains information related tosome of the ktches and the duties that you willbe required t perform such as messenger of thewatch, soup ing and security watch, andcold-iron, watch.' As you progress and becomeacquainted with the fireroom or engioneroomyou will be required to stand otherfwatchesunder the supervision and instruction of a pettyofficer. These watches include: (1) for thefireroomburnerman, blcvwerman, andcheckman; and (2) for the engineroomlowerlevel watch, upper level watch, evaporatorwatch, shaft alley watch, and throttle watch.

MESSENGER OF THE WATCH

The messenger of the watch-- performs anumber of important (1,4t;,,a wilit.h involve agreat' deal of responsibility. The messenger isusually assigned as telephone talker on theengineering JV circuit during close maneuvering

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conditions with other ships, when entering orleaving port, or when refueling or replenishingfrom another ship. Because the JV circuit is usedto provide communications between all theengineering spaces, you must ;-now propertelephone procedures; when you talk, speakslowly and in a very distinct mannerpronouncing Qte syllables of each word veryclearly. When you receive a message, or are givena message to transmit, be sure to repeat it wordfor word, exactly as it was given to you; do notengage in any idle chatter.

As the messenger on the watch you will alsoperform such other duties as the petty officer ofthe warcl may designate. This includes checkingall operating machinery to see that it isoperating, properly, recording temperature andpressure readings in the appropriate logs, andcalling the watch relief.

The' dy,\erating log is an hourly record. ofoperating pressures and temperatures of almostall operating machinery. . The log readingsinclude lube oil pressures and temperatures,boiler pressures and temperatures, pumpsuctions and discharge pressures, and other itemsof importance to the operation of theengineering plant. You will be required to writeand print legibly, to correctly spell commonNavy terms and to maintain your logs neatly andaccurately. You should become acquainted withproper operating pressures and temperatures sothat you will know when a piece of machineryor equipment is not operating properly.

SOUNDING ANDSECURITY WATCH

As a Fireman you will be required to standsounding and security watches. While on this

e44

FIREMAN

watch, your primary mission is to look for fireand flooding hazards. On most ships, this watchis from the end of the working day until 0800the next morning and is also in effect duringholiday routine. The watch is particularlyneeded at these times because there are fewerpersonnel working aboard 'the ship and certainspaces that require frequent observation are notunder the normal observation of personnelworking in or near them. On some ships(particularly the larger ones), sounding andsecurity watches are stood around the clock.When you stand this watch, in addition tolooking for fire and flooding hazards, be surethat no fresh water spigots are leaking or leftrunning in heads, washrooms, galleys, andpantries. Another of your responsibilities whileon watch is to maintain the-proper condition ofmaterial readiness by checking all watertight airports, doors, hatches, scuttles, and all otherdamage controh-fittings. Report any irregularcondition (change in soundings, violations ofmaterial condition, fire hazards, etc.) to yourwatch supervisor.

SOUNDINGS

A sounding tube is usually made ofI I /2-inch pipe. The lower end is fitted at a lowpoint in the compartment, tank, or void whichthe tube serves. The upper end terminates in aflush deck plate which is usually located on themain or second deck; it is closed with a threadedplug or cap.

Tubes are made as straight as possible, butstrrie are, necessarily curved. Some soundingtubes, partichlarly thOse serving spaces under theenginerooms and firerooms, cannOt be extendedto the upper decks because of the constructionof the ship. These tubes terminate in risers

0, which extend approximately 3 feet above theserved; they have gate valvecompartment

closures.Sounding are taken with a sound rod or

sounding tape, whichever is provided for thatpurpose aboard ship. Normally, the soundingrod is approximately 6 feet long and is made of12 -inch lengths of 1/2-inch brass or bronze rods.It is lowered with a chain or line. The soundingtape is a steel tape, coiled on a reel suitable forholding while the tape is lowered. The tape is

'weighted at the end to facilitate lowering intothe sounding tUbe.

HOW TO TAKeA SOUNDING

Wher is relatively hard to see on a brass orbronze sounding rod. Before 'yoU take asounding, dry the rod or tape thoroughly andcoat it with white chalk. When the chalkbecomes wet, it turns to a distinctly visible lightbrown color. For example, if there is 6 inches ofwater in a tank when you take a sounding, thelight brown,color of the chalk will be distinctlyvisible up to the 6-inch mark; while theremainder of the sounding rod will still becovered with the white chalk. The chalk methodis used only where water may be present.

When you have coated the sounding rodwith chalk, lower it down the tube until ittouches the bottom; immediately draw it back.Do not drop the rod or tape to the bottom, butlower it slowly so that it his bottom withoutinjuring the rod or tape. If the ship is rolling, tj,kto lower and hoist the rod or tape while the shipis on an even keel. After you have taken thesounding, enter the reading in the sounding log.

COLD-IRON WATCH

When a ship moves alauside aepair ship or, a tender, or into a naval shipyard,, and is

receiving power from these activities, a securityand'fire watch is usually set by each department.This watch is commonly called the COLD-IRONWATCH.

Each cold-iron watch makes frequentinspections of the area, assigned to him and looksfor fire hazards or other unusual, conditionsthroughout the area. He sees that nounauthorized persons are in his watch area, thatall spaces are cleaned, and that no tools, rags,gear, and the like are left, adrift. He keeps bilgesreasonably free of water.

The watch makes hourly reports to theofficer of the deck as to alt, existing conditions.Any unusual conditions that do exist arereported -to the officer of the deck immediately

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Chapter I3ENGINEERING WATCHES

so that the department responsible can benotified to take the necessary correctivemeasures.

In the event that welding or burning is goingon in his area, the -gold-iron watch sees that afire watch is stationed. (The fire watch stands bywith a CO2 extinguisher.) If none has beenstationed, the cold-iron watch has the workdiscontinued until the fire watch has beenstationed. The cold-iron watch carries out allorders and special orders pertaining to the dutiesof that watch.

If the ship is in drydock,.the cold-iron watchwchecks all sea valves after working hours to see

that the valves are secure or are blanked off. Hemust see that no oil is pumped' into thedrydocks at any time. He Wiill not allow anyweights, such as fuel oil, feedwater,' or potableWater, to be shifted without perniission of theengineeofficer.

LL,

The cold-iron watch must be-a II regulations, instructions, anoNi safetyprecautions and must see t 1W (tites'e arcobserved. He gives his relief aWinformation.regarding existing conditions, orders, and specialorders. If the relieving watch is not satisfied withthe conditions, he will not relieve him, but willreport for instructions to the petty officer withthe day's duty.

BURNAIMAN

The bumerman 'maintains proper steampressure by cutting burneit in or out, or byregulating the fuel, oil ppessure at the burners.The steam pressure must be held at the workingpressure, amqp- as steady as possible. Thebumerman 'must keep a close check for dirtyatomizers, by observing their operation and thecondition of the fire. He changes the atomizerswhen authorized by tyre petty officer in chargeof the watch.

The burner7man depends on a steam pressuregage and ,a superheated steam anaperaturethermometer for information °on conditionswithin the boiler. In most cases anengine'gdertelegraph (annunciator) located near theburner front' so that 'the fireroom watch willknow what main engine changes,ale being Made.

M engine speed and steam conditionschange, the bumerman must rapidly eut burnersin or out, as required, to hold the steam pressure '

steady. -During maneuve'rIng il, close contactwith other ships, and when the ship is enteringor leaving ...port, the bumerman must beconstantly alert for large, rapid changes inengine speed. ';

BLOWERMAN

The blowerman is responsible for operatingthe\ forced draft blowers that supply combustionair to the boiler. Although the air pressure in thedouble casings is affected by the number ofregisters in- use and the extent to which eachregister is open, it is chiefly determined by the,manner in whiCh the forced draft blowers areoperated. The opening, setting, or adjustingofthe air registers is the BURNERMAN'S job. Thecontrol of forced draft bloWers is theBLOWaRMAN'S job. It is important that thebumerman and the blowerman cooperate with

-each other because both are concerned with thecombustion of the fuel oil.

4-

CHECiMAN

The checkinan is responsible for operatingthe feed stop valve and the feed check valve. Thecheckman has ONLY ONE JOBto maintain theproper water level in the boiler: This job requiresfull attention at all times. When a boiler is beingoperated srrianually,the checkman must NEVERbe giVen'any tither duties.

Some ships are equipped with fullyautomatic feedwat on s, so a checkman isnot 'normally needed. Hovyev,T, if the automaticsystem fails or is switched to mantkal control,therra checkmah must be imm diately stationedon the checks.

THROTTLE WATCH

The tasks. of a throttkman at the main,

engines are very important: Orderi from thebridle relative to movement' of the propellers,

'must.be complied with immediately. To. make'

I73

1- 7 9 4

1

ti

FIREMAN

correct adjustments for the required speed, you/must keep a (-lose watch on the rpm indicator onthe throttl board and open or close thethrottle, a required: to attain or maintain thenecessary, rpm. In addition to handling thethrottle itself, you may also have to operate avariety of associated valves, accurately log allspeed changes in the Engineer's Bell Book,visually 'check all gages (pressure, temperature,vacuum, etc.) installed on the throttle board,and keep the petty offices' in charge informed ofany abnormal gage readings.

You should become thoroughly familiarwith all the gages, instruments, and indicators onthe throttle board so. thatypti wilt know what anormal reading is. ThereAare steam pressuregage< steam ternperatur thermometers, arevolutions-per-minute (rpm) indicator, anengine order telegraph, feedwater pressure gages,cooling water pressurepies, gages indicating thevacuum obtained in the main engine low -pressure turbine, and others. Whenever anopportunity presents itself, study thelAhrottleboard and ask questions. Do not hesitate to askthe operator whether those are normal readings,and whether they are the approximate readingsyou should alwaykqee there during steamingconditions. When --ou have learned thedifference between a normal reading and anabnormal reading, you max possibly help- to

prevent a major casualty 'by observing an- abnormal reading and reporting it to the pettyofficer in charge of the watch.

P 0V '

4,

LOWER _VEV*Et. WATCHES

c.When you are assi ed to the lower level to

assist the lower level atch (pumpman) and tolearn his duties and re onsibilities, you will find

considerable n ber of pumps and otherauxiliary machinery. Some of the pumps anVequipment you will find are the main lube oil'pumps and lube oil coolers, main condensatepumps and main conderiser and, when installedin the engineroom, main feed*, pumps, main feedbooster pumps, and 'fire pumps.. In someinstallhtions you 91 als9.--1incl air compressorson the lower level..

In addition, to learning the properprocedures for starting, operating, and stopping

the pumps -and equipment, you must learn tomake various routine checks on the operatingmachinery. Some of the checks for the mainfeed punip, the lube oil pump, and the maincondensate pump.are discussed in the sectionsthat follow. alnder the watchful eye of -thepumpman, you will learn how to make thefollowing checks and to perfbrni the followingduties.

MAIN FEED PUMP

In addition to complying with the postedinstructions and safety precautions for themachinery and equipment at this station, thepumpman performs the following auties:

II 'Maintains main feed pump dischargepressure at a predetermined 'value by adjustingthe constant presire governor,

2. Keeps ihfain feed pump bearing s at theproper temperature by regulatinrtothe flow .ofwater through tha.feed pump lube oil cooler.

3. Checks to ensure proper lube oil pressureto the bearings.

4. Keeps shaft packing glands adjusteliproperly. A small leakage is necessd.0 ,f9rlubrication to prevent burning out the *kilt,but an excessive amount of leakage wastes boilerf eedwater.

5. Checks and maintains proper 1 e oillevel in the main feed pump sump tank.

6. KeeRs valve packing glands tightened toprevent leak4.

7. Keeps his watch station clean; removesfire hazards by wiping up oil and picking up ragsand other stray gear.

Is alert for unusual sounds, vibrations,temperatures, and pressures.

9. Keeps the standby pump ready forinstant use.

LOBE OIL pump

1. Maintains the proper lukke oil' pumpdischarge pressure by adjusting the constantpressure governor.

2. Keeps the stand y -pump bn automaticstandby, ready for i stant use.

3. Shirts and cle s main rube oil strainersonce each watch or mo a ften if required.

Chapter 13 ENGINEERING WATCHES

4. "ChIcks the lube oil system for leaksmaintains the proper off level in the main ensump tank.

5, Operates the lube oil purifier as ordered.6. Checks the oil pres'sure,to the lube oil

service pump bevings and maintains the oil atthe proper ,,tepera,ture by regulating' 'theamount of water through the pump lube oilcooler. ,

7. Regulates the cooling water flowthrough the lube oil cooler go maintain thecorrect oil outlet temperature.

MAIN CONDEN$ATJ PUMP

I. Keeps the condensate in the condenserhot well at the proper level.

2./ Frequently checks the exhaust trunk andm a in condenser overboard for abnorinaltemperatures.

3. Checks the main condensate pumpbearings for proper oil pressure and temperature.

4. Keeps fhe main condenser vented.5. Starts or secures an additidnal pump, as

required, to keep the ;condensate level at thecorrect height.

6. 'Constantly checks fqr . unusualconditions such as vibrations, sounds, and highor low temperature or pressures.

All watch standers should be constantly alert'for signs of leakageln all parts of the steam andwater systems. Some of the more commoncauses of feedwater waste are: (1) leaks in pipefittings, flanges, valve and pump packing glands,pump hodtings and relief valves'? (2) use ofexcessive gland sealinestak and (3) failure toshift drains from-glie.bilie to the appropriatedrain system. Using an excessive amotint ofboiler feedwater is an indication of a poorlyoperated plant and reflects on the lility bf thewatch stander.

UPPER -LEVEL 'WATCH

VVVhen,yoli are"assigned to the dutrerbf theupper level watch in the engineroom, you willrecord , periodic temperature and pressurereadings fr he various gages otw, or connectedto, the upp evel machinery; make required

valve adjustments to correct conditionsindicated by slight variations from the normalreadings, and report unusual con bons to thepetty officer In charge; maintain a normal waterlevel in the deaerating tank, if it is in theengineroom, by adjusting the excess and makeupfeed valves; light off and secure turbogenerators;and other upper level machinery, as ordered; andmaintain an adequate gland seal pressure on theturbogenenitor.

SHAFT ALLEY WATCH

Another main engine duty to which youmay be assigned is that of keeping watch on thebearings of the propeller shafts leading froin thereduction gears (or motors of a turboelectricdriven ship) to the ship's propellers. The shaftalley watch stander:

1. Checks all spring bearings for properlubrication, including correct oil level, conditionof the oil, proper operation of self-oiling devices(ring or cjiain), and bearing temperature.

2. Checks and adjusts stern tube gland forcorrect amount of leak-off.

3. is responsible for having the shaft, alleybilge -pumped.

4. Is to be especially alert during high speedto observe any abnormal , rise in bearingstemperature.

5. Reports hourly, by phone, to the controlengineroom and at any time that abnormalconditions develop:

6. In ships, which have the main thrustbearing in the shaft responsible foroperation of the main thruiT bearing lube oilsystem.

7. Performs any other additional dutieswhich may be assigned.

EVAPORATOR WATCH

A ship requires a large amount of pure freshater daily, yet a ship can only store sufficient

water to last a few dayi; therefore proper andcareful watches must be maintained on theevaporators whenever they are in operation.Proper watch standing requires the operator to

475

181

FIREMAN

constantly check pressures, temperatures,vacuim, and salt content of the distilled water.The stiff) cannot operate if the distilled waterthat is to be used for feedwater contains moresalt than the maximum allowable limits.

OTHER WATCHESOR ASSIGNMENTS

Each division Officer prepares a Watch,Quarter, and Station Bill for his division. Youwill generally find the following information onthis bill:

I. Organization of the division (i.e.,sections and watches).

2. Listing of, each person as to billetnumber, locker number, bunk number,

182176

compartment number, name, rating, and rate(actual and allowance).

3. Watch assignments for each person undervarious conditions of battle readiness.

4. Station each person will have arfd -whathe will provide for emergency situations Such asFire, Rescue and Assistance, and GeneralEmergency.

5. Visit and search party, landing force,spettfl sea detail, and other special duties andstations which each person is assigned.

. The Watch, Quarter, and Station Bill to Isyou where' you fit into the ship's organizatio alpicture. Check it frequently, for it is your dutyto know where you belong udder all conditions.There is NO EXCUSE FOR NOT KNOWING.The bills may be differently designed fordifferent ships,. but the stations and duties arealways approximately the same.

4

is

APPENDIX I

GLOSSARY

, When you enter a new occupation, you mustlearn the vocabulary of the trade so that youunderstand your fellow workmen and can mq,keyourself understood by them. Shipboard liferequires that Navy personnel learn a relativelynew vocabularyeven new terms for manycommonplace items. The reasons for this needare many, but most of them boil down toconvenience and safety. Under certaineircbmstances, a word or a few words may meanan exact thing or may mean a certain sequenceof actions which makes it unnecessary to give alot of explanatory details.

A great deal of the work of a Fireman is-such that an incorrectly interpreted inOruetion-.4could cause confusion, breakage of machinery,or even loss of life. Avoid this confusio4nd itsattendant danger by learning the meaning -ofterms common to the Engineering Department.

This glossary is not all-inclusive, but it doescontain many terms that every Fireman shouldknow. The terms given in this glossary may havemore than one definition; ortly those definitionsas related to engineering are given.

ttBT (automatic pus transfer): An automaticelectrical device that supplies power to vitalequipment. This device will, shift from thenormal power supply to an alternate powersupply any time,'the normal supply isinterrupted.

ACETYLENE: A gas that is chemicallyproduced from calcium carbide and water, usedfor welding and cutting.

ADAPTER: A coupling or similar device thatpermits fittings with different-sized openings(apertures)

fittingsbe joined together.

V

p

AFTERCOOLER: Ai terminal heat- transferunit after the last stage.

AIR EJECTOR: A type of jet pump, used toremove air and other gases from the condensers.

AIR CHAMBER: A chamber, usuallybulb-shaped, on the suction and discharge sidesof a pump. Air in the chamber acts as a cushionand prevents sudden shocks to the pump.

edit REGISTER: A device in the casing of aboiler which ,regulates the amount of air forcombustion and provides a circular motion tothe air. .

AISE: Association. of.lron and Steel Engineers.

ALLOY: A mixture of two or more metals.

ALTERNATING. CURRENT fa-c): Currentthat is constantly changing in value anddirection at regular recurring intervals.

AMBIENT TEMPEof the surrounding area.

mperature

AMMETER: , An instrument for measuring therite of flow of electrical current in amperes.

EALING: Theheatingand slow coolr

A*UNCIATOR:TELEGRAPH.

softening of,. metal bying.

See ENGINE ORDER

, ARGON: An inert gas, slightly heavier,,,than air,used in inert-gas shielded metal arc welding.

177

183

FIREMAN

ARMORED CABLE: An electric cable that isprotected on the outside by a metal covering.

ASTM:` American Society for Testing Metals.

AUTOMATIC COMBUSTION CONTROLSYSTEM (ACC): A system that automaticallycontrols the fuel and air mixture in a boiler.

AUXILIARY MACHINERY: Any system orunit of machinery that supports the mainpropulsion units or helps support the ship andthe crew. Example: Pump, evaporator, steeringengine, air-conditioning, and refrigeratorequipment, !aunt*/ and galley equipment, deckwinch, etc.

IAN'S r"BACK PRESSURE: The pressure'. exerted onthe exhaust side of a pump or engine.

BDC (bottom dead center): The position of areciprocating piston at its lowest point of travel.

BALLASTING: The process of filling emptytanks with salt water to protect the ship fromunderwater damage and to increase its stability.See DEBALLASTING.

BLUEPRINT: Reproduced copy of drawing(usually having white lines on a bluebackground).

BOILER: A strong metal tank or vesselcomposed of tubes, drums,'and headers, inwhich water is heated by the gases ofcombustion to form steam.

BOILER CENTRAL CONTROL STATION: Acentrally, located station for directing thecontrol 6f all boilers in the fireroom.

BOILER DESIGN PRESSURE: Pressyrespecified by the manufacturer, usually about103% of normal steam drum operating pressure;

BOILER INTERNAL FITTINGS: All partsinside the boiler which colntrol the flow of steamand water..

BOILER OPERATING PRESSURE: 'Thepressure required to he maintained in a boilerwhile in service.

BOILER OPERATING STATION: A locationfrom which boilers are operated.

BOILER RECORD SHEET: A NavShips formmaintained for each boiler, which serves as amonthly summary of operation.

BOILER REFRACTORIES: Materials used inthe boiler furnace to protect the boiler fromheat of combustion.

BOILER ROOM: A compartment containingboilers but not containing a station for operatingor firing the boilers. Refers specifically tobulkhead enclosed bo4r installations.

BOILER TUBE CLEANER: A cylindricalbrush that is used to clean the insides of boilertubes.

BOILER WATER: The water actuallycontained in the boiler.

BRAZING: A method of joihing two metals athigh temperature with a molten alloy.

BRINE: A highly concentrated solution of saltin water, normally associated with the overboarddischarge of distilling plants.

BRITTLENESS: That property of a materialwhich causes it to break or snap suddenly withlittle or no' prior sign of deformation.

BULL GEAR: The largest gear in reductiongear trainthe main gear, as in a geed turbinedrive.

BURNERMAN: Man in fireroom who tendsthe burners in The boilers.

BUSHING: A rivewable lining for a holethrough which a moving part passes.

BYPASS: To divert the flow of gas or liquid.'Also, the line that diverts the flow.

CALIBRATION: The comparison of anymeasuring instrument with a set standard.

CANTILEVER: A projecting arm or beamsupported only at one end. .

0

178

/-\ - 184

Appendix I GLOSSARY

CAPILLARY TUBE: A slender, thin-walled,small-bored tube used with remote-reading.indicators.

CARBON DIOXIDE: A colorless, odorless gasused as a fire.( extinguishing agent and forinflating liferafts A-0 lifejackets.

CARBON PACKING: Pressed segments ofgraphite used to prevent steam leakage aroundshafts.

CASUALTY POWER SYSTEM: Portablecables that are rigged to transmit power to vitalequipment in an emergency.

CHECK VALVE: A valve that permits the flowof a liquid in one direction only.

CHILS? SHOCKING: A method that uses steamand cold water to rem9ve scale from'the tubesof a distilling plant.

CHLORINE: A heavy,,greenish-yellow gas usedin water purification, sewage disposal, and in thepreparation of bleaching solutions. Poisonou's inconcentrated form.

CIRCUIT BREAKER: An electrical, device thatprovides circuit overload protection. .4

CLUTCH: A form of coupling designed _tpconnect or disconnect a driving or thenmember.

COLD IRON CONDITION: An idle plant as ina destroyer when all port services are receivedfrom an external ,source such as shore or tender.

CONDENSATE: Water produced in the coolingsystem of the steam cycle from steam that hasreturned from the turbine or from steam that hasreturned from various heat exchanges. The water

.is used over again to generate steam in the boilerfor an endless repetitive cycle.

P

CONDENSER: A heal transfer device in whichsteam or vapor is condensed to water.

CONDUCTION: A method of heat transferfrom one body to another when the two bodiesare in physicalgontact.

179

CONSTANT PRESSURE GOVERNOR: Adevice that maintains a constant pump discharge,pressure under varying'loads.

CONTROLLER: A device Lsed to stop, start,and protect motors from overloads, while themotors are running.

COOLER: Any device that removes heat. Somedevices such as oil coolers remove heat to wastein overboard seawater discharge, and otherdevices such as an ejector cooler conserve heatby heating condensate for boiler feedwater.

CORROSION: The process or being ;atenaway gradually by chemical action, sucfir asrusting.

COUNTERSINK: A cone-shaped tool used toenlarge and bevel one end of a drilled hole.

CREEP-RESISTANT ALLOY:' A metal whichresists the slow plastic deformation that occursat high temperatures when the materialtis underconstant stress.

CROSS-CONNECTED 'PLANT: A method ofoperating two or more plants as one unit from acommon steam supply.

CURTIS STAGE: A velocity-compoundedimpulse turbine stage that has one pressure dropin the nozzles and two velocity drops in theblading.

DEAERATING FEED TANK (DA tank): Aunit in the steam -water cycle that (1) frees thecondensate of diisolved oxygen, (2) heats thefeedw.ater,. and (3) acts as a reservoir forfeedwater.

DEBALLASTING: The process by which salt isemptied from tanks to protect the ship fromunderwater damage and to increase its stability.

DEGREE OF SUPERHEAT: The amount bywhich the temperature of steam exceeds thesaturation temperature.

DIRECT CURRENT (d-c): Current that movesin one direction only.

185

FIREMAN

DIRECT DRIVE: One in which the drivemechanism is coupled directly to the drivenmember.

DISTILLATE: Water produced in distillingplants.

DI STILLING PLANTS: Units commonlycalled evaporators (evaps) used to convertseawater into fresh water.

DRAWING: Illustrated plans that showfabrication and assembly details.

DRUM, STEAM: The large tanlrat the top ofthe boiler in which the steam colltcts.

DRUM, WATER: A tank at the bottom of abOiler; also called MUD DRUM.

DRY PIPE: A perforated pipe at the highestpoint in a steam drum to collect steam.

DUCTILITY: Property possessed by metalsthat allows them to be drawn or stretched.

ECONOMIZER: A heat transfer device on aboiler that uses' the gases of combustion topreheat the feedwater.

EDUCTOR: A jet-type pump (no movingparts) used to empty flooded spaces.

EFFICIENCY: The ratio of the output to theinput.

ELASTICITY: The ability of a material toreturn to its original size and shape.

ELECTRODE: A metallic rod (welding rod),used in electric welding, that melts when currentis passed through it.

ELECTROJIIYDRAULIC STEERING: Asystem <baying a motor-driven hydraulic pumpthat creates the force needed to actuate the ramsto position the ship's rudder.

ELECTROLYSIS: A chemical action that takesplace between unlike metals in syste, using saltwater. . 0

ELECTROMOTIVE FORCE (EMF): A forcethat causff electrons to move through a closedcircuit; expressed in volts.

ELEMENT: A substance which consists ofchemically united atoms of one kind.

ENERGY: The capacity for doing work.

ENGINEER'S BELL BOOK: A legal record,maintained by the throttle watch, of all orderedmair),engine speed changes.

E INE ORDER TELEGRAPH: A device onth ship's bridge to give orders to theen ineroom. Also called ANNUNCIATOR.

EPM (equivalents per million): The number ofequivalent parts of a substanZe per million partsof another substance. The word "equivalent"refers to the equivalent weight of a substance.

EVAPORATOR: A distilling device to producefresh water from seawater.

EXPANSION JOINT: A junction which allowsfor expansion and contraction.

FATIGUE: The tendency of a material tobreak under repeated strain.

FEED HEATER: A heat transfer device thatheats the feedwater before it goes to the boiler.

FEEDWATER: Water of e high t possiblelevel of purity made in vaporat s for use inboilers.

FERROUS METAL: Metal with a high ironcontent.

FIREBOX: The section of a ship's boiler wherefuel oil combustion takes place.

FIRE MAIN:. The saltwater line that providesfirefighting water and flushing water throughoutthe ship.

FIRE TUBE BOILER: Boilers in which thegaSes of combustion pass through the tubes andheat the water surrounding them.

PLARFBACK: A backfire of flame and hotgases into a ship's fireroom from the firebox.Caused by a fuel oil exploSion in the firebox.

180.a

Appendix IGLOSSARY

FLASH POINT OF OIL; The temperature atwhich oil vapor will flash into fire although themain body of the oil will not ignite.

FLEXIBLE I-BEAM: An I-shaped steel beamon which the forward end of a turbine ismounted; it allows for longitudinal expansionand contraction.

FLOOR cLATES: The removable deck platingof a rueroom or engineroom aboard ship.

FLUX: A chemical agent that retards oxidationof the surface, removes oxides already present,and aids fusion.

FORCE: Anything that tends to produce ormodify motion.

FORCED. DRAFT: Air under pressure suppliedto the burners in a ship's boiler.

FORCED DRAFT BLOWERS: Turbine- drivenfans which supply air to the boiler furnace.

FORCED FEED LUBRICATION: Alubrication system that uses a pump to maintaina constant pressure.

FORGING: The forming of metal by heatingand hammering.

FRESH WATER SYSTEM: A piping systemwhich supplies fresh water throughout the Ship.

FUEL OIL MICROMETER VALVE: A valveinstalled at the burner manifold, that controlsthe fuel oil pressure to the burners.

FUEL OIL 'SERVICE TANKS: Tanks whichprovide suction to the fuel oil service pumps todischarge o4-tQ theers.,,,,, -

II., \ ,FUSE: A protective device that will open. acircuit if the current. .flow exceeds apredetermined valtie. -t-z. .''

- .

GAGE GLASS: A device that indicates theliquid level in a tank.

GAS FREE: A term used to describe a spacethat has been tested-and found safe for hot work(welding and cuttjng).

GEARED-TURBINE DRIVE: A turbine thatdrives a pump, generator, or other machinerythrough reduction gears.

GROUNDED PLUG: A three-prongedelectrical plug used to ground portable tools tothe ship's structure.' It is a safety device whichalways must be checked prior to your usingportable tools.

HAGEVAP SOLUTION: A chemicalcompound used in distilling plants. to preventthe formation of scale.

HALIDE LEAK DETECTOR: A device thatisused to locate leaks in refrigeration systems.

HANDHOLE: An opening large enough for thehand and arm to enter the boiler for makingslight repairs and for inspection purposes.

HANDY BILLY: A small portable water pump.

HARDENING: The heating and rapid cooling(quenching) of metal to induce hardness.

HARDNESS: The ability (of a material to resistpenetration.

" HEADER: A chamber, or tank, located withina boiler, to which tubes are connected so thatwater or steam may pass freely from one tube tothe other(s). 'Similar to, but Mailer than-, a

water drum.

HEAT EXCHANGER: Any device that allowsthe transfer of he-at from one fluid (liquid, orgas) to another.

HYDROGEN: A higi r explosive, light,invisible, nonpoisonous as used in underwaterwelding and cutting operations.

4,

HYDROMETER* An instrument used todetermine thevspecific gravity of liquids.

1.81

1.8.7

FIREMAN

,HYDROSTATIC TEST: A pressure test thatuses water to detect leaks in a boiler or in otherclosed systems. 13-

IGNITION, COMPRESSION: When the heatgenerated by compression in an internalcombustion engine ignites the fuel (as in a dieselengine).

IGNITION SPARK: When the mixture of airand fuel in an internal combustion engine isignited by an electric spark (as in a gasolineengine).

IMPELLER: An encased, rotating elementprovided with vanes which draw in fluid at thecenter and expel it at a high velocity at the outeredge.

IMPULSE TURBINE: A turbine in which themajor part of the driving force is received fromthe impulse of incoming steam.

INDIRECT DRIVE: A drive mechanismcoupled to the driven member ,by gears or bets.

INERT: Inactive.

INJECTOR: A device which uses a jet of steamto force water into the boiler. Injectors are alsoused in the diesel engine to force fuel into thecylinders.

INSULATION: A material used to retard heattransfer.

I NT E RCOO LE R: An intermediate heattransfer unit between two successive stages, as inan air compressor.

JACKBOX: Receptacle, usually secured to abulkhead, in which telephone jacks aremounted.

-JOB ORDER: An order issue by ,a re ..jractivity to its own subdivision to perform arepair job in,response to work request.

JUMPER: Any connecting Pipe, hose, or wire,normally used in emergencies aboard ship to

182

bypass damaged sections of a pipe, 'a hose, or awire. (See BYPASS.)

JURY RIG: Any temporary or Makeshiftdevice.

LABYRINTH PACKING: Rows of metallicstrips or fins that prevent steam lebitage alongthe shaft of a turbine.

LAGGING: A protective and confining coverplaced Over insulating material.

LIGHT OFF: Start. Literally, to startiltfffe in,as in "light off a boiler."

LOG- BOOK: Any chronological record ofevents, such as engineering watch log.

LOG, ENGINEERING: A legal record of,.important events and data concerning themachinery of a ship.

LOG ROOM: Engineer's office aboard ship.

LUBE OIL PURIFIER: A unit that removeswater and sediinent from lubricating oil bycentrifutal force.

MACHINABILITY: The ease with which ametal may be turned, planed, milled, orotherwise shaped.

MAIN CONDENSER: A heat ex ner whichconverts exhaust steam to feedwat r.

MAIN DRAIN SYSTEM: , Syst nr used forpumping bilges; consists of pumps andassociated piping.

\;\MAIN INJECTION (sCoOp injection): Anopening in the skiin of a ship through whichcooling water,' ehvered to the main condenser

er by the forward motion

\

and mgiirliofsthe s p.

MAKEUP FEED:" Water of required purity foruse in ship's boilers. This water is needed toreplace that lost in the steam cycle.

' ,ar.

Appendix IGLOSSARY

MALLEABILITY: That property of a materialwhich enables it to be stamped, hammered, orrolled into thin sheets.

MANIFOLD: A fitting with numerousbranches which conveys fluids between a largepipe and several smaller pipes.

MECHANICAL ADVANTAGE (MA): Theadvantage (leverage) gained by the use of devicessuch as a wheel to open a large valve, chain fallsand block and-tackle to lift heavy weights, andwrenches to tighten nuts on bolts.

MECHANICAL CLEANING: A method ofcleaning the firesides of boilers by scraping andwire-brushing.

ROMHOS: Electrical units used withsalinity indicathrs to measure the conductivityof water.

MOTOR GENERATOR SET: A machinewhich consists Of a motor mechanically coupledto a generator and usually mounted on the same,.base.

NAVY BOILER COMPOUN A powderedchemical mixture used in boile w ter treatmentto convert scale- foi`tYli-ng, salts int ludge.

NAVY SPECIALgrade of fuel oil tships.

NIGHT ORDER BOOK: A noteb ok,containing standing and special, instructionsfrom the engineer officer to the -night

.engineering officer of the watch.

NITROGEN: An inert...gas which will not"support life or combustion. Used in recoilsystems-and other -spaces that require an inertatmosphere.

NONFERROUS METAL: Metals thatcomposed primarily of .- some elementelements other than iron.

OIL (NSFO): The -

at the Navy uses icombatant

OIL KING: A petty officer who recoiv.es,transfers, discharges, and lusts fuel. oil Andmaintains fuel oil records.

OIL POLLUTION ACTS: The Oil" PollutionAct of 1924 (as amended) aid the Oil PollutionAct of 1 961 prohibit the overboard discharge ofoil or water, which contains oil, in Port, in anysea area within 50 stiles of land, and in specialprohibited zones.

ORIFICE: A smail opening.

OVERLOAD RELAY: An electrical Protectivedevice which autorhatically-trips when,a circuitdraws excessive current.

,4A

OXIDATION: The process of various elementsand compounds combiningWith oxygen. TIcorrosion of metals' is generally a form ofoxidation; rust on iron, for example, is ironoxide or oxidation.

p, ,

PANT, PANTING: A series of pulsationscaused by minor, recurrent explosions in thefirebox- of a ship's boiler. Usually caused by ashortage of air.

PERIPHERY: Tire curved line which forms theboundary of a circle (circumferepte), ellipse, orsimilar figure.

"PITOMETER LOG: "Device that indicates thespeed -of a 'ship and the distance traveled byieasuring water pressure on a tube projectedoutside the ship's hull.

PLAST-/CITY:. That property which enables a.material to be excessively and, perMan9tly,deformed without breaking.

PNEUMERCATOR: A type. of manometerused to measure the,voltime of liquid in tanks.

t PPM (parts per million): Comparison of theare number of .parts- of a substance' with a milli nOr parts of another substance. Used to measure the

salt content of water.J

PREHEATING: The application. of Mkt to thelase metal before itis elded or cut.

OFFICER OF THE WATCH (00W): Officeron duty in the engineering spaces.

183

1.89

FIREMAN

PRIME MOVER: The source of motionas aturbine, automobile engine, etc.

PUNCHING TUBES: Process for cleaning ,theinteriors of boiler tubes.

RADIATION, HEAT: Heat emitted in theform of heat waves.

REACHPRoDS:#X length of pipe or back stockused as an extension on stems.

REACTION TURBINE: A turbine in which the'major part of the driving. force Is received fromthe reactive force of steam as it leaves theblading.

REDUCER: Any coupling or fitting whichconnects a large opt-King to a smaller pipe orhose.

REDUCING VALVES: Automatic valves thatprovide a steady pressure lower than the supplypressure.

REDUCTION GEAR: A set of gears thattransmit the rotation of one shaft to anothera slower speed.

REEFER: A provision cargo ship or a

refrigerated compartment. An authorizedabbreviation for refrigerator.

REFRACTORY: Various types of heatresistant, insulating material used to line theinsides of boiler furnaces.

RE,FRIGERANT 12 (R-12): A, nonpoisonousgas used in air conditioning and refrigerationsystems.

REGULATOR (gas): ,An instrument thatcontrols the flow of gases from compressed gascylinders.

R EMOTE OPERATlivG GEAR: Flexiblecables attached to valve wheels so the,valves canbe operated from anothencompartment.

4

RISER: A verticalepipe leading off a large One.Example: a fireman riser.

184

ROOT VALVE: A valve located where abranch line comes off the main line.

ROTARY SWITCH: An electrical switch whichcloses or opens the circujt by a rotating motion.

ROTOR: The rotating part of a turbine, imp,mp,or electric motor.

SAE: Society of Automotive Engineers.

SAFETY VALVE: An automatic, .quick -opening and closing valve which has a resetpressure, lower than the lift pressure.

1.

SALINITY: Relative salt content of water.

SALINOM'ETER: A hydrometer that measuresthe concentration of salt in a solution.

SAi,RATION PRESSURE: The pressurecorr sponding to the saturation tem,peratdre.

SATURATION TEMPERATURE: Temperatureat which g liquid boils under a givenpressure. For any given saturation tem-perature there is a corresponding satura-tion pressure.

SCALE: Undesirable deposit, mostly calciumsulfate, which forms in the tubes of boilers.

SECURE: To make fast or safethe ordergiven on completion of a drill or exercise. Theprocedure followed when any piece ofequipment is to be shut down.

SENTINEL VALVES: Small relief valves usedprimarily as a warning device.

SHAFT ALLEY:. The Pong compartment of aship in which the propeller shafts revolve.

SKETCH; A rodgh drawing indicating majorfeatures of an object to be constructed.

SLIDING FEET: A mounting for turbines andboilers which allows for expansion andcontraction.

SLUDGE: The sediment left_in fuel oil tanks.

Appendix IGLOSSARY

SOLID COUPLING: A device that joins twoshafts rigidly.

SOOT BLOWER: Soot removal device (fiatuses a steam jet to clean the firesides of a boiler.

SPECIFIC HEAT: The amount of heatrequired to raise the temperature of I pound ofa substance. 1°F. All substances are compared towater which has a specific heat of I BTU /lb / °F.

SPEED-LjMITING GOVERNOR: A devicet limits the rotational speed of a prime

over.

SPEED-REGULATING GOVERNOR: Adevice that maintains a constant speed on apiece of machinery that is operating undervarying load conditions.

SPLIT ,PLANT: A . method of °O ratingpropulsion plants so that they are divided intotwo or more separate and complete units.

SPRING BEARINGS: Bearings positioned atvarying intervals along a propulsion shaft-to helpkeep it in alignment and to support its weight.

STANDBY, EQUIPMENT: Two identicalauxiliaries that perform onaunction. When oneauxiliary is running, the standby is so connectedthat it may be started if the first fails.

STATIC: A force exerted by reason of ightalone as related to bodies at rest or in bal' ce.

STEAMING WATCH: Watches stood when themain engines are in use and the ship isunderway.

STEAM LANCE: A device that uses lowpressure steam to remove .3,--.;°t Cluin insideboiler's and to remove carbon from boiler tubes.

STEERING ENGINE: The machinery thatturns the rudder.

STERN TUBE: A watertight enclosure for therkerpeller

STRAIN: The deformation, or change in shape,of a material which results from the weight ofthe applied load.

185

STRENGTH: The ability of a material to resiststrain. .

STRESS: A force which produces or tends toproduce, deformation in a metal.

STUFFING BOX'. 'A device to prevent leakagebetween a moyitig and a fixed part in.a steamengineering plair(

STUFFING TUBE: A packed tube that makesa watertight fitting for a cable or small pipepassing through a bulkhead.

SUMP: A container, compartment, or- reservoir,used as a drain or receptacle for fluids.

SUPERHEATER: A unit in the boiler that drysthe steam and raises its temperature.

SWASH PLATES: Metal plates in th; lowerpart of the steam drum that prevent the surging

of boiler water with the motion of the ship_ _

SWITCHBOARD: A panel or group of panels,,with automatic piotective devices that distributeelectrial power throughout the ship.

TAKE LEADS:- A method of determiningbearing clearance.

TANK TOP: Top side oank section or,double bottom of a ship.

TDC (top dead center): The position* of areciprocating piston at its uppermost point oftravel.

TEMPERING: -The heating and controlledcooling of a metal to produce the desiredhardness.

THIEF SAMPLE: A sample 'Of bfl or watertaken frornla ship's tank for analysis.

THROTTLEMAN: Map in the engineroom whoOperates the throttles to control the main

engines.

THRUST BEARING: A bearing that limits theend play and absorbs the axial thrust of a shaft.

FIREMAN

TO BLOW TUBES: To use steam to removesoot and carbdn from the tubes of steamingboilers.

TOP OFF: To fill up, as a ship tops off, withfuel oil before leaving port.

_TOUGHNESS: The property of a materialwhich enables it to w thstand shock as well as tobe deformed witho breaking.

TRANSFORMER:step up or step do an a-c voltage.

An electrical device used to

TRICK WHEEL: A steering wheel in thesteering engineroom or emergency steeringstation of a ship.

TUBE EXPANDER: A tool that expandsreplacement ,tubes into their seats in boilerdrums and headers.

a.

TURBINE: A multibladed rotor driven bysteam or hot gas.

TURBINE JACKING GEAR: A motor-drivengear arrangement that slowly rotates idlepropulsion shafts and turbines.

TURBINE STAGE: One set of nozZles and thesucceeding row or rows of moving blades.

UPTAKES (exhaust trunks): Large enclosedpassages for exhaust gases o rnovefromboilersto the stacks.

VENT: A valve in a tank or compartment thatprimarily permits air to escape.

VENTURI INJECTOR: A devic'e used to washthe firesides of boilers.

\)492l86

VOID: et. small empty compartment Itowdecks.

VOLATILE: The term that describes a liquidwhich vaporizes quickly.

VOLTAGE TESTER: A portable instrumentthat4etects electricity.

WATER TUBE BOILER: Boilers in which thewater flows through the tubes an is heated by .the gases of combustion.

WATER WASHING: A method of cleaning thefiresides of boilers to rerve soot and carbon.

LWELDING LEAD: The conductor throughwhich electrical current is transmitted from thepower sOurce to the electrode holder andwelding rod.

WHELPS: Any of the ribs or ridges on thebarrel of a capstaQ or windlass.

WIPED BEARINGS: A bearing in which thebabbitt has melted because of excess heat.

WIREWAYS: Passageways betteen decks andon1he overheads of co

Vartments that contain

electric cables.

WORK REQUEST: Request iced to navalshipyard, tender, or repair ship for repairs.'

ZERK FITTING: A small fitting to which agrease gun can be applied to force lubricatinggrease into bearings or moving _parts ofmachinery.

ZINC: A metal placed in saltwater systems tScounteract the effects of electrolysis.

tlf

s.

APPENDIX II

TOIE METRIC SYSTEM

The metric system was developed by Frenchscientists in 1790 and was specifically designedto be an easily used system of weights andmeasures to benefit science, industry, andcommerce. The metric system is calculatedentirely in powers of 10, so one need not workwith the various mathematical bases used withthe English system, such as 12 inches to a foot,3 feet to a yard, and 5280 feet to a mile.

The system is based on the "meter" which isone ten-millionth of the distance from theEquator to the North Pole. It is possible todevelop worldwide standards from this base dfmeasurement. The metric system of weights isbased on the gram, which is the weight of aspecific quantity of water.

Soon after the system was developedscientists over the world adopted it and wereable to deal with the 'mathemaircs of their'experiments more easily. The data andparticulars of their work could be understood byother scientists anywhere in the world..Duringthe early 19th century many European nationsadopted the new system for engineering andcommerce. It was possible for these countries totrade manufactured goods with one anotherwithout worrying whether it would be possibleto repair machinery from another countrywithout also buying special wrenches andmeasuring tools. Countries could buy and sellmachine tools and other sophisticated andprecision machinery without troublesomemodifications or alterations. It was much easierto teach the metric system, since meters cjn bechangefr-tcl kilometers or centimeters with\ themoveitent of a decimal point, which is roughlylike being able to convert yards to miles orinches by adding zeros and a decimal instead ofmultiplying by 1760 or dividing by 36.

*44

0

With the exception of the United States,-allthe industrialized nations of the world haveadopted the -metric system. Even England andCanada are changing from their traditionalsystems of measure, and the mptric system willbe almost universal by 1980.

Although the metric system has not beenofficially legislated by the Congress, the metricsystem is becoming more prominent in thiscountry. Most automobile mechanics own somometric, wrenches to work on foreign cars orforeign components in American 'cars. Almost allphotographic equipment is built to metricstandards. Chemicals and drugs are usually soldin metric quantities, and "calorie counters" areusing a metric unit of thermal energy.

Because we are allied with countries who usethe metric system, much of Our militaryinformation is in, metric terms. Military maps usemeters and kilometers instead of miles, andmany weapons are in metric sizes, such as 7.62mm, 20 mm, 40 mm, 75 mm, and 155 mm.Interchange of military equipment has caused amixture of metric and English measureequipment since World War I when the armyadopted the French 75 mm field gun, and WorldWar II when the Navy procured the Swedish 40mm Bofors and the Swiss 20 mm Oerlikon heavymachine guns.

It is inevitable that the United States willofficially adopt the metric system. Exactly whenthis happens and how rapidly the changeoverwill depend on economics, since the expense ofretooling our industry and commerce to newmeasurements will be very great. The cost ofconversion will be offset by increased earningsfrom selling machinery and products overseas.Another benefit is that scientists use the metricsystem, but their calculations now have to be'

187

193

FIREMAN

translated into English measure to be used byindustry. With adoption of the metric systemideas can go directly from the drawing board tothe assembly line.

The Navy will be using the metric systemmore during the next few yioars. Although youwill find it easier to solve problems using thissystem, at first you will find it difficult tovisualize or to estimate quantities in unfamiliarunits of measure.

Fortunately many metric units can berelated to equivalent units in the English system.

The meter which is the basic is

approximately one-tenthltonger than a yard.

The basic Emit of volume, the liter, is

approxiMately one quart. The gram is the weightof a cubic centimeter, or milliliter, of pure waterand is the basic unit of weight. As a commonweight though, the kilogram, or kilo, whichequals the weight of a liter of water, weighs 2,2pounds. The cubic centimeter (cc) is used wherewe would use the square inch. and where wemeasure by the fluid ounce. the metric systememploys the milliliter (ml). For power measurethe metric system uses the kilowatt (kW), whichis approximately 1.3 horsepower.

In terms of distance, a land n c is

eight-fifths of a kilometer and a nautical mile is1.852 kilometers. or nearly 2 kilometer

A basic metric expression of pressure thekilogram per square centimeter, which is 4.2psi. nearly I atmosphere of pressure.

When working on foreign machinery, youmay notice that your-half-inch, three-quarterinch, and one-inch wrenches will fit many of thebolts. These sizes correspond to 13 mm, 19 mm,and 2 mm respectively in the metric system,and are very popular use they are

interchangeable. The I af nch spark plugwrench, which is standar this country, isintended to fit a 20 mm n

194188

The basic quantities of the Metric system aremultiplied or divided by powers of 10 to giveother workable values. We cannot easily measuremachine parts in terms of a- meter, so 'themillimeter, or one-thousandth of a meter is used.For very fine measure thernicron, also called themicrometur, can be used. It is one-millionth partof a meter, or one-thousandth of a millimeter.For small, weights the milligram, one-thousandthof a gramexpressedLatin:

is used. All of these multiples arewith standard prefixes taken from

micro I ,000,000milli 1/1,000cent' 1/100

*deci 1/10*deco 10

*hecto 100kilo I ,000

*myna 10,000mega 1,000,000

* Rarely used

Over the next few years the metric systemwill become more used by the Navy as well as bythe civilian world. You will find it easy to work ,

with once you have mastered the basic terms. Itwill be difficult to translat values from ourpresent system to the metric s m, but thisoperation will become unpecessary o e the newmeasurements are totally adopted.

Tables of equivaleriT English measure andmetric equivalents are essential when you worksimultaneously with both systems. The tablewhich follows shows the equivalent measures ofthe two systems. The columns on the left havethe equivalent values which are accurate enoughfor most work. and on the right are themultiples used to convert the values with a high

'degree of accuracy.

/e

Appendix IITHE METRIC SYSTEM

THESE PREFIXES MAY BE APPLIED

TO ALL SI UNITS

Vittipla sad SmbewItip Iss

1 000 000 000 000 = 10"1 000 000 000 = 10'

1 000 000 = 10'

i 000 = 10'

100 = 101

10= 10

0.1 = 10-'

0.01 = 104

0.001 = 10-'

0.000 001 = 104

0.000 000 001 = 100.000 000 000001, = 1041

0.000 000 000 000 001 10-"0.000 000 000 000 000 001 = 104'

Most commonly mut

Prefize3 Symbols

tera (WO T

giga (Pgif) G

mega (megler) M

kilo (kill) k

hecto (helet6) h

deka (deed) da

deci (des% d

centi (seta) c

milli (mill) mmicro (mi'krii) AL

nano (nan16) n

pico (pesk6)

femto (fernsto)

atto (ert6) a

pf

195

189

1

FIREMAN

Multiply By To Obtain Multiply Bye

To Obtain

Acres 40.41 Ares Feet . 30.48 Centimeters

Acres 4,041 Centares - Feet 0 1661 Fathoms

Acres 10 Square chains Feet 0.3048 Meters,

Acres 43,560 Square Feet Feet per Minute 0 01136 Miles per Hour

Acres 1,840 Square Yards . Feet per Second 0 5921 Knots

Ares 0 02411 Acres Feet per Second 18.288 Meters per Minute

Ares 100 Centares Feet per Second 0.6818 Miles per Hour

Ares 1,076 Square Feet Furlongs 10 Chains

Ares 119.6 Square Yards Furlongs 660 Feet

Barrels (U.S., dry) 3.281 Bushels Furlongs 40 Rods

Barrels (U.S., liquid) 4.21 Cubic Feet Furlongs 220 Yards ..

Barrels (U.S., liquid) 31.5 - Gallons Gallons (British) 4,546.1 Cubic Centimeters

Board Feet (1' x 1' x 1') 144 Cubic inches Gallons (British) . 0 1605 Cubic Feet

Cable lengths (U.S.) 120 Fathoms Gallons (British) 211.214 Cubic Inches

Cable lengths (U.S.) 120 Feet Gallons (British) 1.2009 Gallons (U.S.)

Cable lengths (U.S.) 240 Yards Gallons (British) 4.546 Liters

Centares 10.16 Square lel Gallons (British) 4 Quarts (British)

Centares

Centimeters

1.196

0 3931

Square yards

Inches

Gallons (U.S.? 0 03115 Barrels (hold,U.S.)

Cubic Centim'eters 0 06102 Cubic Inches Gallons (U.S.) 3,185.4 Cubic Centimeters

Chains 66 Feet Gallons (U.S.) 0 13368 Cubic Feet

Chains 100 Links Gallons (U.S.) 231 Cubic Inches

Chains 4 Rods Gallons (U.S.) 0 8327 Gallons (British)

Cubic Feet 1,128 Cubic Inches Gallons (U.S.) 3.185 Liters

Cubic Feet 0 02832 Cubic Meters Gallons (U.S.) 4 Quarts U.S.)I

Cubic Feet 0 03104 Cubic Yards Grams 15.43 Grains

Cubic Feet 6.229 , Gallons (British) Grams 0 001 Kilograms

Cubic Feet 1.481 Gallons (U.S.) Grams 1,000 Milligrams

Cubic Feet 28.316 Liters Grams 0.035,2? Ounces (ayon

Cubic Inches 16.39 Cubic Centimeters dupois)

Cubic Inches 0 0005181 Cubic Feet Hands 10.16 Centimeters

Cubic Inches 0 003606 Gallons (British) Hands 4 Inches

Cubic Inches 0 004329 Gallons (U.S.) Hectares 2.471 Acres

Cubic Inches 401639 Liters Hectares 100 Ares

Cubic Meters 35,S.1 Cubic Feet Hectoliters 0 1 Cubic Meters

Cubic Meters L308 Cubic Yards Hectoliters 26.411 t Gallons (U.S.)

Cubic Yards 21 Cubic Feet Hectoliters 100 Liters

Cubic Yards

Cubic Yards

0 1646

164.6

Cubic Meters

Liters

.. Hogsheads 2 Barrels (Liquid,

U.S.)

Degrees (C.)+ 11.8 1.8 Degrees (F.) Hogsheads (U.6.) 63 Gallons (U.S.)

Degrees (F.) -32 0 5556 __.DZees (C.) Hundredweights..0 508 Quintals (metric)

(:),e-grees , 0 01145 r Rad)ons Inches 12 Points

Fathoms 0.00833 Cable Lengths (U. Inches 6 Picas

S.) Inches 6 Ems

Fathoms ti Feet Inches 12 Ens

Fathoms 1.8288 Meters Inches 2.54 Centimeters

196

190

O

9Appendix II THE METRIC SYSTEM

Multip ly By To Obtain Multiply By To ObtainInches 0.0833 Feet Miles, Nautical 6,016.1 FeetInches 1,000 Mils Miles, Nautical 72,363 InchesInches 0.0277 Yards Miles, Nautical 1.8532 KilometersInches of Mercury 0.49131 Pounds per Square Inch Miles, Nautical 5 1,853.2 MetersKilograms 1,000 Grams Miles, Nautical 1.1508 Miles, StatuteKilograms 2.2046 Pounds (Avoir-

dupois). Miles, Nautical 1 Minutes.of

LatitudeKiloliters .1 / Cubic Meters Miles, Nautical 2,026.8 YsKiloliters 1.300 Cubic Yards Miles per Hour Off Fe Si per Minute

, Kiloliters 264.18 Gallons (U.S.) (Statute)Kiloliters 1,000 Liters Miles per How 1.467 Feet per SecondKilometers 4.557 Cable Lengths (Statute)Kilometers 3,280.8 .Feet Miles per How 0.8684 KnotsKilometers , 39,370 Inches Miles, Statute 7.33 Cable LengthsKilometers 1,000 Meters Miles, Statute 5,280 FeetKilometers 0.5396 Miles, Nautical Miles, Statute 6 8 48 FurlongsKilometers 0.62137 Miles, Statute Miles, Statute 63,360 InchesKilometers 1,093.6 Yards Miles, Statute 1.6093 Kilometers .Knots 1.1516 Statute Miles per Miles, Statute 1,609.3 Meters

How Miles, Statute 0.8689 Miles, NauticalKnots ,1.688 Feet per Second Miles, Statute 1,760 Yards.Leagues, frautical 25.33 Cable Lengths Millier (See Tons -Leagues, Nautical 5.5597 Kilometers Metric)

,

Le ues, Nautical 3 Miles, Nautical Milliradians 206.265 Seconds of ArcLeagues, Statute 4.8280 Kilometers Mils 0.001 InchesLeagues, Statute 3 Miles, Statute , Myriameters 10 KilometersLinks 7.92 Inches Ounces (avoirdupois) 28.3495 GramsLiters 1,000 Cubic Centimeters Pint (Liquid, U.S.) 4 Gills (U.S.)Liters 61.025 Cubic Inches Pint (Liquid, Br.) 4 Gills (British)Liters 0.21998 Gallons (British) Pint (Liquid, Br.) 0.56825 Liters,Liters 0.26418. Gallons (U.S.) Pint (Liquid, U.S.) 0.4732 LitersLiters , 0.8799 Quarts (British) Pounds (avoirdupois) 7,000 GrainsLiters 0.908 Quarts (U.S.,dry) Pounds (avoirdupois) 453.59 GramsLiters 1.0567 Quarts (1-00. Pounds (avoirdupois) 0.4536 Kilograms

.

U.S.) Pounds (avoirdupois) 16 OuncesMeters 100 Centimeters Pounds (avoirdupois) 1.2153 Pounds (troy)Meters 0.001 Kilometers' Pounds (troy) 0.8229 sounds (avoir-Meters 1.0936 Yards dupois)Meters 3.281 Feet Pounds per Square Inch 2.03537 Inches ofMeters 39.37 Inches MercuryMeters 1,000 Millimeters Quart (British) 1.1365 LitersMeters 1.0936 Yallit'. Quart (British) 2 Pints (British)Meters per Minute 0.0541 Feet per Second Quart (Liquid, U.S.) 0.9463 LitersMeters per Second 2.237 Miles per Hour Quart (U.S.) 2 Pints (U.S.)Microns 0.001 Millimeters Quintals (Metric) 1.97 HundredweightsMiles, Nautical 8.44 Cable Lengths Quintals (Metric) 100 Kilograms

197191

1 'N.

FIREMAN

)

Multiply By To Obtain Multiply By To Obtain

Radians 57.30 Degrees Square Miles, Statute 259 HectaresRods 16:3 Feet Square Miles, Statute 2.59 r Square KilometersRods 25 Links Square Yards '-0.8362 CentaresSquare Centimeters 1;1550 Square Inches Square Yards 9 Square FeetSquare Feet 0.b929 Centares Square Yards 1,296 Square InchesSquare Feet 929 Square Centimeters Tpns (Long), 1.016 Metric TonsSquare Feet 144 s Square Inch -.J Tons (Long) 2,240 Pounds (Avoir-Square Feet 0.1111 Square Yards dupois)Square Inches 6.452 Square Centimeters Tons (Metric) 1,000 KilogramsSquare Inches 0.006944 Square Feet . (Millier)Square Kilometers . 100 Hectares ,Tons (Metric) 2,204.6 PdAls (Avoir-Square Kilometers 0.3861 Square Miles (Whe) dupois)

(Statute) Tons (Short) 0 9072 Metric TonsSquare Meters (See

Cen tares)Tons (Short) 2,000 Pounds (Avoir-

dupois)Square Miles, Statute 640 Acres Yards 91.44 CentimetersSquare Miles, Statute 25,900 Ares Yards 0.9144 Meters

O

198192

A

A-c generators, 144-146Advancement, preparing for, 1-4Advancement rewards, 4Air compressors, 94Air conditioning equipment, 89Air registers, 62Anchor windlass and capstan, 92Appendix I, glossary, 177-186Appendix II, metric system, 187-192Assembly, boiler, 56-60Atomizers, 60Auxiliary machinery and equipment, 88-99Auxiliary steam cycle, 53-55

B

Basic steam cycles, 48-55Batteries, 151Battle lanterns, 151-153Bellows gages, 103,Bimetallic dial thermometers, 104Blowerman, 173Boiler assembly, 56-60Boiler technician (BT), 12Boilermaker (BR), 13Boilers, '6-71Boilers, classification of, 62-65Boilers, new high-pressze, 68-70Bourdon tube gages, 100-103.Burnerman, 173Burners, fuel oil, 60-62

C

Capstan and anchor windlr 92Checkman, 173

INDEX

elassification.of boilers, 62-65, furnace arrangement, 65

location of fire and water spaces, 62type of superheater, 65types of circulation, 64

Cold-iron watch, 172Combustion, 28CondensatiorerbConstant-pressuiRiump governors,. 125-128Converting power to drive, 38*

clutches and reverse gears, 44r-46reduction gears, 39-41

Cranes, 95

D

D-c generators and exciters, 144Damage control assistant, 8Diaphragm gages, 103Diesel-driven generators, 146Diesel electric drive, 35Diesel engine drive, 36-38Diesel engines, 158-165

air sOtem, 160'cooling system, 163fuel system, 161lubrication system, 162power system, 159starting systems, 164valve mechanism, 160

Diesel-powered boat operation,, 69Distant-reading dial thermometer, 104Distilling plants, 90

E

Electric motors, 150motor controllers, 151d-c and a-c motors, 1

193

199

1

lr

o.

FIREMAN

Electrical equipment, shipboard, 143-155Electrical officer, 8Electrical safety precautions, 154Electrician's Mate (EM), 13-15Electricity introduction, 143

electric current, 143electromotive force, 143resistance, 144watt, 144

Elevators, 96-98Energy, 18Engineer officer, 5Enginernan (EN), 11Equipment, portable, 151-153Evaporator watch, 175Expansion, 49-51Engineering department, 5-16Engineering department organization, 5-10Engineering department ratings, 10-16

boilermaker (BR), 13boiler technician k BT), 12electrician's mate (EM), 13-15engineman (EN), 11hull maintenance technician (HT), 15interior communications eleetrician (IC), 15machinery repairman (MR), 12machinist's mate (MM), 10molder (ML), 15patternmaker (PM), 15

Engineering funda entals, 17-30

iiEngineering instrum nfttl 12-115

engi e order tel aph, 114lube oil pressure alarm, 114salinity indicator, 113smoke indicator, 113steam flow indicator, 112superheater temperature alarms, 112

Engineering watches0171-176

F

Feed, 51-53Fire marshal, 9Fireman rate, 1-3Fireroom safety precautions, 70Fluid meters, 107-109Force, 17Fuel oil burners, 60-62

air registers, 62atomizers, 60

Furnace arrangement, 65

J

200194.

Gage glasses, 106Galley equipment, 99Gas-free engineer, 9Gas turbine engines, 166 -169

comparison of gas turbines andreciprocating engines, 167

components of gas turbine engines, 168Gaskets and packing, 137Gasoline engines, 165(;eared- turbine drive, 31-33Generation, 49Generator and distribution switchboards, 148Generator types and drives, 144-147

a-c generators, 144-146d-c generators and exciters, 144diesel-driven generators, 146

. ship's service turbine-driven generators, 146Glossary, appendix I, 177-186

H

High-pressure boilers, new, 68-70Hull maintenance technician (HT), 15Hydraulics principles, 22-24

Information sources, 3Instruments, 100-115Interior communications electrician (IC), 15Internal combustion engines, 156-170

L

Laundry equipment, 99Lighting distribution systems, 154Liquid lei/el indicators, 106

gage glasses, 106tank gaging system, 106

Liquid-in-glass thermometers, 104-106bimetallic dial thermometers, 104distant reading dial thermometers, 104pyrometers, 105,

Lovvei level watches, 174lube oil pump, 174main .c)ndensate pump, 175main feed pump, 174 -0,,

INDEX

Lube oil pressure alarm, 114Lube oil purifiers, 93Lubrication, 84-87

;),

M

MachineryV equipment, auxiliary, 88-99Machinery repairman (MR), 12Machinist's mate (MM), 10Main propulsion assistant, 7Main propulsion, double-reduction gearing,

81-83Main steam cycle, 49-53

condensatiog, 51expansion, 49-51feed, 51-53generation, 49

Manometers, 103Messenger of the watch, 171Metals, 29Meters, fluid, 107-109Metric system, appendix II, 187-192Molder (ML), 15

N

NBC defense officer, 8Naval boilers, other, 65-68New high-pressure boilk,rs, 68-70

0

Operation of small boat engines, 169diesel powered boat operation, 169gasoline engine operation, 170

Organization of engineering department, 5-10damage control assistant, 8department administrative assistant, 6department fra.ining officer, 7.division officeri, 9electrical officer, 8engineer officer, 5enlisted personnel, 9fire marshal, 9gas-free engineer, 9main propulsion assistant, 7NBC defense officer, 8technical assistants, 9

.s?

P

Packing and gaskets, 137Patternmaker (PM), 15

Physics, 17-29combustion, 28energy, 18

Fl

force, 17laws of gases, 19mass, weight, and inertia, 17power, 19pressure and vacuum, ;0-22principles of hydraulics, 22-24principles of pneumatics, 24-27

,...speed, velocity, and acceleration, 17steam, 29temperature, 27work, 18

Piping, 134-137pipe fittings, 136 -

piping definitions, 134-136piping materials, 136

Pneumatics principles, 24-27

Portable equipment, 151-153battle lanterns, 151-153portable extension lights, 153portable tools, 153sealed beam lights, 153

Power distribution systems, 15ePreparing for advancement, 1-4

Pressure gages, 100-10Vbellows gages, 163Bourdon tube gages, 100-103diaphragm gages, 103manometers, 1()3

}Principles of ship propulsion, 31Propeller, 46Propulsion, ship, 31-47Propulsion units, typical, 31-38Pump governors, constant-pressure, 125-128Pumps, 116-125

centrifugal, 122jet0124propeller, 123

4. reciprocating, 117-121rotary, 121

Pyrometers, 1105

195

201

FIREMAN

R

Ratings, engineering department, 10-16Reciprocating engines, 156-158

ignition principles, 156operating cycle, 156-158

Reduction gears, 39-41, 81-87lubrication, 84-87main propulsion, double-reduction

gearing, 81-83reduction gear construction, 83

Refrigeration equipment, 88Resistance, 144Reverse gears and clutches, 41-46Revolution counters and indicators, -109-112

S

Safety precautions, electrica1,154Safety precautions, fireroom, 70Salinity indicator, 113Sealed beam lights, 153Shaft alley watch, 175Ship propulsion, 31-47Ship propulsion principles, 31Shipboard electrical equipment, 143-155Shipboard electrical systems and connections,

153lighting distribution systems, 154power distribution systems, 154shore power connections, 154

Ship's service turbine-driven generators, 146Small boat engines, operation of, 169Smoke indicator, 113Sounding and security watch, 171

soundings, 172Steam, 29Steam cycles, basic, 48-55Steam flow indicator, 112Steam traps and drains, 140-142Steam turbines and reduction gears, 72-87Steering gears, 91Strainers, 137-140Superheater temperature alarms, 112Superheater, type of, 65Switchboards, 147-150

components of a switchboard, 148-150generator and distribution switchboards,'

14

196

2O2

T.

Tank gaging system, 106Thermometers, liquid-in-glass, 104-106Thermometers and pyrometers. 103Throttle watch, 173

Turbines, 72-81classification of turbines, 72-77construction of turbines, 77-81

Turboelectric drive, 33-35

Typical propulsion units, 31-38diesel electric drive, 35 ,

diesel ehgine drive, 36-38geared-turbine drive, 31-33turboelectric drive, 33-35

Upper level watch, 175

V

Vacuum and pressure, 20-22

Valves, 128-134check, 130reducing, 133relief, 132safety, 134stop, 128-130stop-check, 131throttle, 132

Watch, 171-175 '4

cold-iron, 172evaporate, 175lower level, 174messenger, 171shaft alley, 175throttle, 173upper level, 175

Watch messenger, 171Watches,engineering, 171-176Watt, 144Winches, 98

OCCUPATIONAL STANDARDS

Firemen,(FN) train for one of the general or, service ratings of Engineering and Hull Group VII.Firemen stand messenger, cold iron, and fire watches; clean engineering spaces and eq3ipment;make minor repairs to engineering equipment; record readings of gages; participate in generaldrills; and perform general detail duties.

40(

The observance of proper safety precautions in all areas is an integral part of each billet and the, responsibility of every Navy man and woman: therefore, it is a universal requirement for all ratings.

OCCUPATIONAL STANDARDS ei Coveredin

Assignment25 NAVAL ORIENTATION AND ORGANIZATION

25251 Identify organizational structure of the engineering department 1

28 TECHNICAL DRAWINGS

28286 Read a three-view working drawing

28287 Use damage-control drawings to locate principal valves in main 1,4,5steamline .4

30 MECHANICAL MAINTJOPERA -AUX EQUIPMENT

30609 Locate refrigeration equipment, anchor windlasses, distillingplants, compressors, steering engines, cranes, elevators, winches,and the following pumps: fuel oil service, fuel oil transfer, fire

r and flushing, fire and bilge, main lubricating oil, fresh water,,condensate, main circulating, main feed,'main feed booster, acrdemergency feed pump

30610 Operate centrifugal and reciprocating pumps using checkoffsheet

30611_

Define functions of the folloWing auxiliary equipment: aircompressors, distilling plants, refrigeratiaplants, fuel oilheaters, lube oil coolers, main and auxiliary condensers, airejector condenser assembly, a.c. and d.c. generators and motors,and pumps

. 197

203

4,5

4,5

4,5

ft

OCCUPATIONAL STANDARDS -

31 MECHANICAL MAINT/OP,ERA-PROPULSION0

31376 Read fuel, water, oil, air and steam'gages, indicators, andthermometers

31377 Identify basic types and component parts of:A. Naval boilersB. Steam turbinesC. Reduction gearsD. Propeller and shaftingE. Shipboard electrical systemsF. Internal combustion engines

-31378 Define functions of valves found in engineering systems

31379 Pealikm functions of boat engineer_

.31380 Replace gaskets and repack valves in law pjessure steam and 5,water piping systems

c.

31381 Perform minor ejgine maintenance . ,6) \

31382 Trace path of main steam from boiler to engine and back to 1,4,5boiler, naming eitial fittings, piping, and main machinery

Covered. in

'Assignment

1

through which it

31383 Define principles of maiTand auxiliary steam cycles ,\

31384 Define basic principles of:A. Mass, weight, and inertiaB. Force energy, and powerC. ,.velocity, and accelerationD. Pressure and vacuumE. Hydraulics And pneumaticsF. Combustion, heat, and temperature

31385 Recognize common engineering terms and nomenclature

31386 Assist in perfornfance ormaintenance.using maintenance,requirement cards (MRC)

Use weekly 3-guschedule to determine maintenance assignments'31387

38 ADMINISTRATION1

38001 File- shlip's blueprints

2 0 4 .

198 ,

2

1,21,21,21,21,21,2

OCCUPATIONAL STANDARDS

42 GENERAL WATCHSTANDING

422421 Stand following engineering watches:A. Fire watchB. Messengerc:'C. Cold ironD. Sounding and security watch

4243 Mai in required records at watch station

94 MECH i ICAL MAINTENANCE

94368 Use and maintain handtools4r

94369 Use lubricating oils and greises

'

I

205

199

f

Jo'

Coveredin

Assignment

6666

3

ff

FIREMANI .

NAVEDTRA 10520-E

Prepared bythe Naval Education and Training Program DevelopmentCenter,_ Pensacola, Florida

4

Your NRCC contains A set of assign-ments and self-scoring answer sheets(packaged separately). Tt)e Mate TrainingManual"Fireman, NAVEDTRA 10520-E, isyour textbook for the NRCC. If an erratasheet comes with the NRCC, ma e all indi-cated changes or correttions.. notchange or correct the textboolc ssign-

iments in any other way.

HOWTOCOMPLETETHIS COURSE SUCCESSFULLY

Stud e textbobk pages given atthe begi nin of each assignment beforetrying o an wer the items. Pay attentionto tabte an ustrations as theycontain a lot of information. Making yourown drawings can help you understand thesubject matter. Also, read the .learnengobjectives that precede the sets of itemsThe learning objectives and items arebased on the subject matter or studymaterial in the textbook. The objectivestell you what you should be able to doby studying assigned textual material

7"and answering the items.

At this point you should be ready4 to answer the items in" the assignment.

Read each item carefully.aSelect theBEST ANSWER for each item, consultingyour textbook when necessary. Be sureto select the BEST ANSWER from the

. subject matter in the textbook. You maydiscuss difficult points in the course,with others. However, the answer youselect must be your own. Use only theself- scoring answer sheet designatedfor your assignment. Follow the scoringdirections given on dhe answer sheetitself and elsewhere in this course.

Your NRCC will be administered byyour command or, in the case of smallcommands, by the Naval Education and'Training Program Development Center.No matter who administers your courseyou can complete it successfully byearning gradeS that average 3.2 or

higher. If you are on active duty, theaverageof your grades in all assign-ments must be at least 3.2. If you areNOT on active duty, the average of yourgrades in all assignments of eachcreditaable unit must be at least 3.2.The unit breakdown of the course, ifany, is shown later under Naval ReserveRetirement Credit.

WHEN YOUR.COURSE IS ADMINISTEREDBY LOCAL COMMAND

As soon as you have finished anassignment, submit the completed self-scoring answer sheet to the officerdesignated to administer it. He will

% chock the accuracy of your score anddiscuss with you the items that you donot understand. )(Cod may wish to record

. your score on the assignment itself sincethe self-scoring answer sheet is notreturned.

If you are completing this NRCC tobecome eligible to take the fleetwideadvaricement examination, follow aschedule that.will.,enable you to completeall assignments in time. Your scheduleShould( call for the completion of atleast bne assignment per month.

Although you complete the coursesuccessfully, the Naval Education andTraining Program Development Center willnot issue you a letter of satisfactorycompletion. Your command will make a note.in your service record, giving you creditfor your work.

WHEN YOUR COURSE IS ADMINISTEREDBY THE NAVAL EDUCATION AND TRAPIINGPROGRAM DEVELOPMENT CENTER

After finishing an assignment, goon to the next. Retain each completedself-scoring answer sheet until youfinish all the assignments in a unit (orin the course if it is not divided intounits). Using the envelopes provided,

206

mail your aelf-ocoreki answer oheetOtO theNaval Education and Training ProgramDevelopment Center where the scores willbe verified and recorded. Make oure allblanks at the top of each answer sheetare filled in. Unless you furnish all theinformation required, it will beimpossible to give you c edit for yourwork. You may wish to rec rd your scoreson the assignments since e oelf-ocoringanswer oheetn are not returned.

The Naval Education and Training4

Program Development Center will issue aletter of satisfactory completion tocertify successful completion of thecourse (or a creditable unit of thecourse). To receive a course-completionletter, follow the directions given ofthe course-completion form in the backof this NRCC.

NAVAL RESERVE RETIREMENT CREDIT

This course is evalUated at 10NaValReserve retirement points. These pointsare creditable to personnel eligible toreceive them under current directivesgoverning retirement of Naval Reservepersonnel. Points will be credited uponsatisfactory completion of the entirecourse.

You may keep the textbook andassignments for this course. Return themonly in the event you disenroll from the

ODURSE 011IECTIVEcourse or otherwise fail complete thecourse. Directions for re urning thetextbook and assignments are given on thebook-return form in the back of thisNRCC.

PREPARING FOR YOUR ADVANCEMENTEXAMINATION

Your examination for advancement isbased on the Manual of Navy Enlisted Man-power and Personnel Classification andOccupational Standards (NAVPERS 18068-D).The sources of questions in this examine-tion,.are given in the Bibliography for Ad-vancement Study (NAVEDTRA 10052). Sinceyour NRCC and textbook are among thesources listed in this bibliography, besure to study both in preparing to takeyour advancement examination. The stand-ards for your rating may have changedsince your course and textbook wereprinted, so refer to the latest editionsof NAVPERS 18068-D and NAVEDTRA 10052.

When you complete this course, youwill halt abroad concept of how theengineering plant works from the beginningof the steam.cycle in the fireroom throughthe engineroom and return to the fireroom.You will have a general knowledge of thepiping and auxiliary systems needed tooperate a steam plant. You will have abroad view of the electrical distribu-tion system, damage control, and small'boats. You will have been introducedto the engineering'Iplant organizationand the types of watches stood byengineering personnel.

While working on this nonresidentcareer course, you may refer freely tothe text. You may seek advice and instruc-tion from others on problems arising inthe course, but the solutions submittedmust be the result of your own work and -.decisions. You are prohibited from re-ferring to or copying the solutions ofothers, or giving completed solutions toanyone else taking the same course.

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4

Naval nonresident career courses may include a variety of items multiple-choice;lue-falSet. matching, etc. The items are not grouped by type; regardless of type, they are presented in the same

general sequence as be textbook material upon which they are based. This presentation is designedto preserve continuity of thought, permitting step-by-step development of ideas. Some courses usemany types of items, others only a few. The student c4n readily identify the type of each item (andthe action required of him) through inspection of the SampIes given below.

MULTIPLE-CHOICE ITEMSEach item contains several alternatives, one of which provides the best answer to the item..

Select the best alternative and erase the appropriate x on the answer sheet.

SAMPLEs-1. The first person to be appointed Secretary of Clefense The erasure of a correct answer is in-

under the National Security Act of 1947 was dicated in this way on the dhswer sheet:1. George Marshall2. James Forrestal3. Chester Nimitz4. William Halsey °II I Is-i

TRUE-FALSE ITEMSDetermine if the statement is true or false. If any part of the statement is false the state-

ment is to be considered false. Erase the appropriate box on the answer sheet as indicated below.

The erasure of a correct answer is alsoindicated in this way on the answersheet:

SAMPLEs-2. Any naval officer is authorized to correspon

officially with a bureau of the Navy Departmentwithout his commanding officer's endorsement. 2

L_MATCHING ITEMS IS -2 CC

Each set of items consists of two columns, each listing words, phrases or sentences. The taskis to select the item in column B which is the best match for the item in column A that is beingconsidered. Specific instructions are given with each set of items. Select the numbers identifyingthe answers and erase the appropriate boxes on the answer sheet.

SAMPLEIn items s-3 through s-6, match the name (7-IFi shipboard officer in column A by selecting from

column B the name of theNepartment in which the officer functions.

A. Officers B. Departments

s-3. Damage Control Assistant 1. Operations Department

s-4. CIC Officer 2. Engineering Department

s-5. Assistant for Disbursing * 3. Supply Department

s-6. Communications Officer

The erasure of a correct answer is in-dicated in this way on the answer sheet:

How To Score Your Immediate Knowledge of Results (IKOR) Answer Sheets

T F

99

C

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Total the number of in- Sample onlycorrect erasures (thosethat show page numbers)for each item and placein the blank space atthe end of each item.

Number of boxeserased incorrectly 0-2 3-7

Your score 4.0 151)

Now TOTAL the column(W6f incorrect erasures and find your score in the Table at thebottom of EACH answer sheet.

NOTICE: If, on erasing, a page numbe,r appears, review text (staFting on that page) and erase againuntil "C", "CC", or "CCC" appears. For courses administered by the Center, the mdximumnumber of points (or incorrect erasures) will be deducted from each item which does NOT havea "C", "CC", or "CCC" uncovered (i.e., 3 pts. for four choice items, 2 pts. for three choiceitems, and -1 pt. for T/F ieema).

iii

208

lo

Assignment 1Preparing for AdvanceneVIssAngineering Department and Enghaporing Fundamental°

Textbook Asaignment: Chapter° 1, 2, and 3

In this couroo you will demonotrato that learning hao taken place by correctly anowering teach-ing item°. Tho mere phyoical act of indicating a choice on an answer ohoot io not in itself impor-tant; it io the pentrq achievement, in whatever form it may take, prior to the physical not that ioimportant and toward which nonreoident career couroe learning objectives are directed. The °electionof the correct choice for a nonreoident career course teaching item indicate° that you have ful-filled, at leant in part, the nted objective(n).

Tho accomplishment of certain objective°, for example, a Alynical act ouch ao drafting a memo,cannot readily bo determined by means of objective typo nonresident career course items; however, youcan demonotrate by means of anowero to teaching items that you have acquired the requiaite knowledgeto perform the phyoical act. The accomplishment of certain other learning objeotivea, for example,the mental. act° of comparing, recognizing, evaluating, ohooping, selecting, etc., may be readilydomonotrated a nonresident career courne by indicating the correct answers to teaching items.

The com re enoive objective for thia oourae has already been given. It atatea the purpose ofthe oourae terms of what you will be able to do ac you complete the oourae.

The de iled objectives in each aaaignment state what you ahould accomplish aa you progressthrough the course. They may appear aingly or in clusters of olooely related objectives, aaappropriate; they are followed by items which will enable you to indicate your accomplishment.

All objectives in this course are learning objectives and items are teaching items. Thry pointout important thinga, they assist in learning, and they should enable tyou to do a Letter JA forthe Navy.

This aelf-atudy course is only one part of the total Navy training program; by .1.3 very aatureit can take you only part of the way to a training goal. Practical experience, achools, selectedreading, and the desire to accompliah are also neceasary to round out a fully meaningful trainingprogram.

Learning Objective: Recognize the gen-eral duties of a Fireman and identifythe bagic military and professionalrequirements for advancement. Textbookpages 1 through 4.

1-tl. A Fireman trains for1. Ordnance2. Operations3. Supply4. Engineering

what group of ratings?

1-2. Aboard ship, the tasks performed by aFireman include standing security andfire watches in the engineering spacesand serving as messenger for damagecontrol repair parties.

1

1-3. The petty officers you assist aboard shipwill give you opportunities to performtasks on your°own before showing yol.ektowto do them.

1-4. The knowledge factors of a professional ora military requirement for advancement aresubdivisions of the requirement that specifythe

1. mental skills one must have toperform the duties of the rating

2. physicalskills one must have toperform the duties of the rating

3. performance tests one must pass4. physical skill tests one must pass

1-57 The qualification standards for advance-ment in rating listed in the Manual ofNavy Enlisted Manpower and PersonnelClassifications and Occupational Standardsare the1. maximum requirements2. average requirements3. minimum requirements4. suggested, but not necessary require-

ments

209

1-6. Which.of the following publications [Mouldyou consult to find the military and pro-foot:lona' requirements for advancement?1. NAVSEA Journal2. Manual of Navy Enlisted Manpower and

Personnel Classifications and Occupa-tional Standards

3. List of Training Manuals and Corre-spondence Courses

4. Basic Military Requirements '

1-7. Before you can take the examination foradvancement, there must be en entry inyour service record to prove that you havequalified in the

ge factors

1. professional qual orations2. knowle3. military qualifica ons4. practical factors

1-8. Upon being transferred another dutystation, you should make sure that yourNAVEDTRA 1414/1 is1. among your personal papers2. retained by your division officer3. destroyed and a new one started at

your new duty stationin your-rarvice record

1-9. The final requirement that must be metbefore you are eligible to take theexamination for advancement is 'the1. required length of service in pay grade2. satisfactory completion of the prac-

tical factors for the next higher rate3. completion of training manuals for the

next higher rate4. recommendation by your commanding

officer

1-10. A recommended publication for finding .

titlesof reference materials to helpyou prepare for your servicewide exami-nation is the latest-revision of1. Bibliography for Advancement Study2. NAVSHIPS Technical Manual3. Manual of Qualifications for Advance-

ment in Rating4. Military Requirements for Petty

Officer 3 and 2

1-11. How will you rqpognize the trainingmanuals in the Bibliography for Advance-ment Study that you must complete 'to

come eligible to take an examinationfo vancement?1. They are listed by title in especial

column under your rating2. Their titles are each marked with a

dagger3: They are listed by title ''in a,"manda-

tory completion" column4. Their titles are marked with

asterisk

1-12. Which of the following publications willbe useful to you when you study foradvancement in rating?1. Tools and Their Uses2. Blueprint Reading and Sketching3. Rate Training Manual4. All of the above

Learning Objective: Identify theadministrative and operationalfunctions of the engineering depart- -

ment and the eleven Group VII ratings.Textbook pages 4 through 16.

1-13. Men assigned to the engineering departmentwill probably be called upon to repairwhich shipboard equipment?1. Computers2. Electric motora3. Fire control radar sets4. Loran gear

1-14. Assists is to the engineer officer Lallyinc lud the

1. da ge control assistant, repairofficer, and electronics officer

2. electrical officer, main propulsionassistant,sand damage control,assistant

3. main propulsion assistant, C divisionofficer, and electricalOofficer

4. damage control assistant, operationsofficer, and the main propulsionassistant

cP

1-15. The duties and responsibilities of theengineer officer are established by1. the Chief of Naval Personnel2. the commanding officer3. the Naval Ship Engineers enter/4. U.S. Navy Regulatiorlf

1-16 Who aids the engineer officer by screeningall his incoming mail and controlling theissuance of directives which he hasreleased?1. Engineering department administrative

assistant2. Leading Yeoman assigned to the

engineering department3. Leading Yeoman assigned to,the ship's

office4. A technical assistant assigned to the

engineering department

2,;.0

, 1-17. In a typical organization of a largenhip's engineering department, the mainpropulsion assistant, the damage controlassistant, and the electrical officer areresponsible to the1. gas-free engineer2. engineer officer3. engineering division officer4. NBC defence officer

1-18 Which of the following are duties of theengineering department training officer?1. Observing instructions given at drills,

on watch, and on station2. Supervising the preparation of train-

ing materials3. Routing information about available

service schooling4. All of the above

1-19. Which of the following responsibilitiesbelongs to the'main propulsion assistant?1. Preparing the Engineering Log and Bell

Book2. Supervising the engineering department

yeoman''N\L Training ship's personnel' in emergency

repair work4. Maintaining the ship's power and

lighting systems

1-20. The duty station of a Fireman assigned tothe M division of a ship is probablylocated in one of the1. enginerooms2. firerooms3. repair shops4. auxiliary spaces'

1-21. Which of the following practices are bestfor learning the locations of steam valves

4 in a ship's fireroom?1. Ask a petty officer from the B.-division

to point out each valve on the ship'sblueprint and then memorize theselocations

2. Trace all the steam 1\nes from begin-ning to end with the aid of the ship's ,

blueprints and.diagrams and then ask 1-30.the engineer dfficer to point out eachvalve

1-22. Tate training of personnel to fight firmsoard nhclip is administered by the'

1. ship's training officer2. damage control assistant3. adminintrative.annistant to the

engineer officer4. B division leading petty officer

In items 1-23 through 1-27, select the divisionof the shipboard engineering department fromcolumn B that is responsible for the tusk givenin column A.

A. Tasks

1-23. Operating air com-pressors

1

1-24. Preserving watertightintegrity

Maintaining firefighting 4. M divisionequipment

1-26. Maintaining gyro-

B. Divisions

1. R division

2. A division

3. E division

compasses

1-27. Operating steam-driventurbogenerators

1-28.

1-29.

3. Memorize the location of all the valveswith the aid of the ship's blueprintsand verify the information on yourfirst trip through the fireroom

4. Learn the location of a few valves ata time with the aid of the ship'sblueprints and diagrams and actuallytrace steam lines from beginning toend

3

A fireman assigned to E division may beexpected to work in which of the follow-

, ing spaces?1. Main motor room2. IC room3. Electric repair shop4. Each of the above

A

Who is responsible for training personnOiin nSnmedical defensive measufes againstNBC attack?1. Ship's training offi2. Damage control s atant3. Leading petty o' icer in A division4. Leading DC petty officer

,J

Wech of the follo ing are duties of theNBC defense office ?1. 'Maintenance o' NBC defense equipment2. Decontaminat on of personnel. and ship3. Transport on of NBC casualties4. All. of t e above

1-31. If one of the voids in your ship is opened,which of the following is the duty of thegas-free engineer to perform?1. Determine whether personnel may safely

enter the void2. Determine whether Wig safe for

welding in the area3. Do both i and 24. Ensure that each welder in the area has

a firewatch checking for explosive gases

211

1-32. As one of his duties, a division of cer

recommends changes to the allowance 0 his

division. He makes his recommendationdirectly to the1. commanding officer2. department head

4) 3. division's technical assistant4. department admin strative assistant

1-33. Aboirrd a large steam - driven ship, the oilking supervises the op ration of1. small boats2. motion picture projeaCtors3. transfer and booster umps

4. steam turbines

1-34. Small boat engineers are usually of whatratings?1. FN, EN, or IC2. HT, EN, or FN3. FN, EN, or MM,

4. EN, FN, or MR

1-35. It is desirable that a Fireman striking '

for an engineering rating (Group VII) havea knowledge of which of the following?1. Mathematics2. Physics3. Mechanical drawing4. All of the above I

Ih items 1-36 through 1-38, select from column Bthe rating of personnel who perform the tasks inyolumn A.

A. Tasks B. Rating.

1-36. Pour castings of 1. Molder -ferrous metals

-'91 -37. Operate millir2. Boilermaker

machines 3. Machinery Repairman

1-38. Repair boiler 4. Machinist's Mateequipment

'1-39. The main propulsion turbines are main-.tained by what rating?1. Boiler Technician2. Machinist's Mate3. Machinery Repairman4. Engineman

1-40. Whic of the following ratings has therespo sibility for making repairs on theemerge cy generator diesel engines?1. Machinist's Mate

Machinery Repairman3. Engin@man

Electrician's Mate

1-41. Hull Maintenance Techniciano perform whichof the following duties?1. Plan, supervise, and perform tasks

necessary fqx!abrication, installa-tion, and repair of allatypes ofstructures

2. Perform tasks relating to shipboarddamn fp control, CBR defense, andfirefight ng

3. Supervis and train personnel inmainte nce, hull repair, CBR defense, '

and damage control4. All of the above

Learning Objectives Recognize thebasic principles of physics thatapply to shipboard machinery andequipment to produce work. Textbookpages 17 through 21.

L 4

1-42. Matter can be defrined as anything thatoccupies space nd has definite1. shape

2. volume3. weight4. visibility

1-43. What is meant by the inertia of astationary object?1. 'Quantity of matter which the object

contains2. Force with which the object is pulled

toward the center of the earth'PhysicalPhysical property that keeps theobject '&t rest

4. Measurement of the mass and the weightof an object'

1-44. An object moving at a constant velocitywill eontinue moving at the same speedin the same direction until acted uponby some outside force. i

4

1-45. Which of the following definitionsdescribes the force that is exerted

con a stationary object?1. A push or pull with which you cause

or try to cause an object to move2. A quantity that keeps the object at

rest3. A quantity of matter contained in the

object

4. A physical property that causes amoving object to continue moving

21.2

1-46. Which of the following is a measure of .

velocity? ,

1. 50 revolutions2. 50 rpm clockwise3. 50 rpm per }sec counterclockwise4. 50 rpm per sec clockwise

Information for items 1-47 through 1-49:

Assume that an object at rest was placedin motion and moved along a straight path.During the first 4 minutes of travel, the

'velocity of the object was marked at 1-minuteintervals as shown by the following table:

Mark

0-minutelrminute2-minute3-minute4-minute

Velocity

0 ft/sec5 ft/sec

20 ft/sec10 ft/sec15 ft/sec

1-55. Energy that exists because of tht$relativevelocities of two-oramore objects is called1: potential energy2. kinetic energy3. energy in transition4. both energy in transition and potential

energy

O

1-56. Expended energy can be measured in workunits of1. horsepo2. specif heat3. Btu4. foot-pounds

In items 1-57 through 1-59, select the definitionfrom columnB that best describes the term incolumn A.

1-47. What was the average acceleation of the 441-57.objeCt during the first minUte?1. 0 ft per sec 1-58.2. 2.5 ft per sec3. 15 ft per sec 1-59.4. 20 ft per sec

1-48. The object was decelerating between thesecond and third minute marks.

1,419. During the first 4 minutes, the object

accelerated and decelerated at uniformrates.

In items 1-50 through 1-53, select from column Bthe, source of the, type of energy in column A.

A. Type of Energy

1-50. Mechanical

1-51. Electrical

1-52. Nuclear

1-53. Thermal

B. Source

1. Sun

2. Battery

3. Auto piston

4. Reactor

1-54. Which of the following situations indi-cates potential energy?1. Water striking a water wheel2. Water behind a dam3. Steam passing through a nozzle4. Water being converted to steam

A. Term B. Defini4on

gY

Power

1. Applicatidn of forcethrough a distance

2. Capacity for producingWork an effect

3. Amount of force per unit

oarea

o4. Time rate of doing work

1-60. How much work is done when a 60-pound boxis raised from the ground to the top of an80-foot platform?1. 60 ft-lb2. 140 ft-lb3. 480 ft-lb4. 4,800 ft-lb

1-61. A motor-driven hoist lifts a 165-poundload to a height of 50 feet in 30 seconds.How much power does the motor develop?1. 1/4 hp2. 1/2 hp3. 3 fip

4. 10 hp0

1-62. What is the horsepower of a pump that canlift 2,500 lb of water per minute from a

`depth of 66 feet?-1. 4 hp2. 5 hp3. 6 hp4. ,40 hp

1=63. How much work can be done by,a 4-horsepowerengine?1. 2,200,000 foot-pounds of work per

minute-Z. 132,000 foot-pounds of work per

minute .

vs 3. 22,000 foot-pounds of work per minute04. 142,000 foot-pounds of work per hour

1 -64. According tiCbarleslaw, if the tem-perature of Alexibfe container of air

I'were doubled, the volume of air would

. 1. be reduced by one -half

2'4 be reduced to one quarter the originalvolume A

3. remain Constant' ut the pressure woulddouble

4. be increased to &ice the originalvolume

I

qa

6

1-65.a

214

A 5-gallon closed steel'tank is full ofwater. `What happens to the pressut'e andvolume of the water in the tank when itstemperature rises?1. Pressure increases; volume remains

constant2. Pressure decreases; volume increases3. Hoek pressure and volume remain the

same4. Prepsure decreases; volume remains the

same

"Assigitriieitt 2 /Engineering Fundamentals; Ship Propulsion; Basic Steam Cycle

Textbook Assignment: Chapters 3, 4, and 5 >

Learning Objective:. Recognize thebasic principles of physics thatapply to shipboard machinery andequipment to produce work. Textb knages 21 through 30.

2-1. Compared with water, how heavy ismercury?1. One-fourteenth as heavy2. The same weight3. Fourteen times as heavy4. Fifty times as heavy

2-2. The forces in a mercurial barometerwhich balance each other are the1. forces exerted by the atmosphere

and the weight of a column of mercury2. force exerted by steam under pres-

re and the force exerted by theweight of a column of mercury

3. weight of a column of mercury plusthe force exerted by the air in thetube above the mercury, and theforce exerted by the atmosphereplus 14.7 psi

4. weight of a column of mercury, andthe pressure of the vacuum abovethe mercury,plus the force exertedby the atmosphere

2-3. At sea level tle.absolute pressure in anair tank measures 31 inches of mercury.How much more or less than atmosphericpressure is the pressure in the airtank?

1. 1 inch less2. 1 inch more3. 2 inches less4. 2 inches more

_J

. If a barome r reads 28 inches of mercury,what is the lmospheric pressure inpounds per square inch?1. 0.986psi2. 13.72 psi

.., 3. 14.70 psitp 16,68 psi

2-5. At sea level the pressu in a tire is24 psi gage.. The absolute pressure inthe tire is approximately1. 9 psi2. 24 psi'

. 3. 33 psi4. 39 psi

2-6. The pressure of the air in a space atsea level is 27 -In. of mercury. What isthe pressure reading of the vacuum gage?1. 3.0 in. of mercury2. 12.3 in. of mercury3. 27.0 in. of mercury4. 45..7 in. of mercury

2-7C What is the absolute pressure of a ;pacefor which the vacuum gage reading is 20in. of mercury?1. 10 in of mercury2. 20 in. of mercury.3. 30 in of mercury4. 40 in. of mercury

2-8. What is the approximate absolute pres-sure of a space in which the vacuumreading is 4 in. of mercury?1. 2.0 psi2. 4.0 psi3. 12.7 psi4. 16.7 psi

2-9. If a pressure gage must be located at apoint below ,the pipe of the pressureline being measured, th," vading on thegage includes the I exerted bythe weight of the 'iquid abovethe gage.

7

2 I 5

0

2-10. PA Williams obtains a reading on a waterpressure gage of 18 psi. The gage islocated 3 feet above the water pipe.Williams calculates the actual pressureof the water to be1. 16.7 psi2. 18.0 psi3. 18.4 psi,4. 19.3.psi

1

40Items 2-11 through 2,414'are related tofigure 1A.

2-11 If a certain fprce is applied to thesmall piston, what are the relationshipsbetween pressuies in various parts ofthe system?

t-

1. The pressure on the small piston isgreater than the pressure on thelarge piston

2. The pressure on the small cylinderis the same as the pressuDE-Actingagainst the small piston and isgreater than the pressure in thelarge cylinder

3. The pressure in the connecting tubeis the same as the pressure in thesmall cylinder and is greater thanthe pressure in the large cylinder

4. The pressure is the same on all partsof all surfacee-.that enclose theliquid

to.

2-13. What is the relationship between A, theforce applied to the small piston, andB, the force exerted by the large piston?1. Force B minus force A 10 lb

2. Force B is 10 times force to3. Force A plus force B o 10 lb4. Force Ais 10 times force B

2-14. The area of the small piston in a hydraulic 'pfess is 3 square inches and the area 91the large piston is 75 square inches. Ifa.force of 50 pounds is applied to thesmall piston, the large piston will(neglecting frictiohal losses) exert aforce of1. 25 lb

2. 250 lb4,

3." 725 lb

4. 1,250 lb

2-15. How is the water removed froM the mainballast tanks when a submerged submarineis surfacing?1. Motor-driven pumps syphon off the

water2. The water is forced out with air3. The water flows-out thrIgh the phits

under the pull of gravity4. Hydraulic pumps syphon off the water

2-16. The heat produced in a nail which isbeing.hammered into a piece of wood isenergy caused by1. physical changes in the nail2. the increased motion of the molecules' .

in the nail3. chemical, changes in the nail

4. the friction between the hammer andthe nailhead

2-17. Heat is defined as the flow of thermalenergy.

2-18. How many calories are there in 25 Britisthermal units?

2-19.

2-12. If the weight onk'the large piston justbalances the weight on the small pistonit follows that the1, force per unit of area is the same

on both pistons2. weights onythe two pistons are equal

3. force on the large piston equals thaton the small piston

4. pressure is greater below the smallpiston than it is below the large

piston 21 08

1. 25

2. 252

3. 2,5204. 6,300

In which of thsofollowi4 forms of matterare the molecu!s closest together?1. Steel2. Boiling water3. Gas4. Chilled water

4

2-20. A block of ice at 32° F is allowed tomelt into water at 32° F. The thermalenergy needed to bring about this changeof state is referred to as1. internal heat2. specific heat3. latent heat of fusion

sensible heat

2-21. H much heat is required to change 10 lbof ce at 32° E to water at 50° F?

\. Z. ,440 Btu180 Btu

3. 1,620 Btu4. 16,200 Btu

2-22. How much heat is required to change 10 lbof water at 82° F to steam at 212° F?1. 82 Btu2. 130 Btu3. 1,300 Btu4. 11,000.0tu

2-23. When ice is changed tolisteam, the greatestamount of heat is required for1.- changing the ice at 32° F to water at

32° F2. heating the water from 32° F to 150° F..3. heating the water from 150° F to 2-31.

212' F4. changing the water at 212° F to steam

at 212' F

.

2-28. All of the following are products_ ofcombustion except1. .sulphur dioxide2. carbon dioxide3. nitrogen4. oxygen

2-29. ,The com4eteness wit4(

0

which fuer,oil burnsin the cylinders of a dieeel enginedepends on ,

1. how well the fuel is mixed with air.2. how much air is present in the

cylinder3. how much timeime the fuel-aiy mixture

is allqwed to burn4. all lie above factors '44

2-30. If water is placed in a closed containerand boiledLt,e steam, will be saturated,when the

.1. pressure in the container increases'2. temperature of the water rises above

212° F3. temperature of the steam risk above

212° F4. water changes Completely to steam at

the temperature of boiling water

2-24. The amount o heat released by steam whenit changes in water at the sametemperature is c led1. sensible heat2. latent heat of condensation3. latent heat of vaporization4. latent heat Of fusion

V-25. A reading of 75' C is equivalent to1. 160° F2. 163° F3. 167° F4. 170° F

2-26 A reading of 77° F is equivalent to1. 23' C2. 25° C3. 27° C4. 29° C

2 -27. A Fahrenheit thermometer and a Celsiusthermometer are placed into water thatcontains melting ice. What are theTowest possible temperature readings tobe expected?1. 0° on Celsius and 32° on Fahrenheit2. 0° on Celsius and 0° onFahrenheit3. 32° on Celsius and 0° on Fahrenheit4. 32° on Celsius and 32° on Fahrenheit

At 1 pressure of 110 psi absolute, waterboils at 335° F. What is the actualtemperature of superheated steam at110 psi absolute when it has 200° F ofsuperheat?1. 310° F2. 412° F3. 535° F4. 665° F

2-32. If you hammer a sheet of copper intgitheshape of a hollow bowl, you are takingadvantage of what property of the metal?1. Strength "

2. Malleability3. Hardness4. Toughness

2-33. What property of a metal permit it tobe shaped into wire form or sheets?1. Strength2. Ductility3. Hardness4. Toughness

2-34, All of the following are ways to reducecorrosion to steel except1. adding nickel or chromium pr both2. chogaing a better grade of base metal3. pa4Sting the surface with a good

grade of_paint.4! coating the surface with ir.;<[ofide

?

0

7

0

2-35. You can determine whether a metal isferrous or nonferrous by using a magnet

cbecause most metals containing iron aremagnetic.

What technique is used in marking a steelbar according to the continuous Identifi-cation marking system?1. A continuous strip of specified4Lidth

is painted along the entire lengthof the bar Po F

2. The appropriate marking is painted onwith heavy ink at specified intervalsalong the bar's length

3. The appropriatsjiarking is punched onwith a metal Olfter at specifiedintervals along the bar's length

4. The appropriate symbol of specifiedcolor is painted on each end of thebar

Learning Objective: Recognize the0- basic principles of ship propulsion.

Textbook pages 31 through 33.

2-37: What type of force (thrust) is developedagainst the velocity imparting devicesshipboard) and causes the ship to move

thrbugh the water?1. Acceleration2. Inertia

,4 3. Reaction4. "TorqUe

2-38.

1 2-39.

In answering ithms 2-38 through 2-41,refer to. figure 4-1 of your textrok.

The thrust on the propeller is transmittedto the ship by means of the1. strut2. main shaft3. high - pressure turbine

4. math reduction gear.

fThe prime mover of the ship's propulsionunit shown 1.1.1 the figure consists of a1. geared turbine2. diesel engine3. generator and turbineter generator and diesel engine

2-40. The reactive force along the axis of themain shaft is absorbed by the1.'.slrut bearing2. stern tube bearing3. line shaft bearings4 thrust bearing.,-

2-41: The strut, stern. tube, and line shabearings funceion to support the mshaft and keep it aligned.

Learning,Ohjective: Identify thevarious'types of propulsion units.Textbook pages 4 through 36.

15W

10

One f, the main differencekibetwe -a

tur oelectric drive and a Para urbinedri e is that the former uses'1. a46maller Vatio.toreduce.turbine

speed to propeller)! speed AL2., a laraer'ratio to q.Uuce turbine

speed to propeller speed3. a cruising turbine to reduce turbine

speed' to propeller speed

4. an electrical means instead of aturbine element to reverse propellershaft rotation

2-43." By which of the foilowing is the speed.of a diesel d=c electric-driyenincreased? t' L1. Increasing generator'vortage ""%e:101KI,

2. Increasing,engine speed.3. Combining changes inagenerator

voltage and engine si$0114. Any of the above ,'

2-44. In diesel d-c electric-diiven ships thedirection of rotation of the propelleris reversed by1.' using reverse.gears2. reversing the flow of current through

the motor3. reversing the direction of rotation

of the diesel engine4: reversing the pitch of the propeller

blades

2-45. Advantage(s) of the diesel engine overthe gasoline engine as the prime moverof a propulsion...unit for a naval vesselinclude1. less dan er:of fire "2. cheaper fuel3:1--standardiz4 fuels4. all of the above

21.8

Learning Objective: Identify reductiongears and clutch°, used to convert powerto drive. Textbook paqs 38 through47.

.. .

2-46. By what means are low propeller-shaftspeedo obtained in ship° driven by high-.speed diesel, engines?1. Clutcheo2. Reverse gears3. Reduction gears

.4. Pitch-changing devices

2-47. How are the opeeds of turbineo and pro-pellers related when a proputsion plantio operating at maximum efficiency?1. Turbines are operating At high speeds;

propellers at low speeds. . Propellers are -operating at high

speeds; turbines at low speeds3 Both turbines and propellers are

operating at high speeds4. Both propellers and turbines fire

.

operating at low speeds

2-48. End thrust imparted to b shaft by, reduc-ticin gearing can be eliminated throughthe use of1. single-helical gears2. do4ble-helical geais3. spur gears4. worm wheels

2-49. That isvpical about a double reductionpropulsi gear arrangement?1. Each double helical gear used does

the work of tt single- helical gears. Turbine speed is twice propeller

speed3. The rpm pro&ced by the turbine is

reduced in YWo steps4. Its efficiency is doUble that oL s

single-teduction gear

2-50. Most diesel-driven ships and boats arebacke&down by reversing the1. pitch of the propeller2. direction of rotation of the propeller

ohaft3. position of the engine relative to

the propeller shaft4. rotation of the engine crankshaft

2-51. Regardless of type or aize'df inatalla-non, the arrangements of clutch, reverse'gear, and reduction gear are the same.

11

2-52. Which of the following statement° Oboutclutcheo io faloe?1.. Friction clutcheo con be cl000ificd

as diok or band and wet or dry2. Simple friction clutcheo may be used

alone in engine° with power ratingsao high ao 2,000 hp

3. Wear occuro on a wet clutch duringengagement, dioengagement, and .

operation4. Coot iron ourfaceo are good for

friction clutches becauce theyreoiot ocoring and ocuffing

2-53. What type of clutch in uoed in the clutchaoaembly of the Gray Marina tranomiooionmechaniom2,1. Dry-type, single-diok2. Dry-typo, twin -diok3. Wet-type, single-diok4. Wet-type, twin-dick'

2-54. An astern operation of the ohaft and .

propeller driven by the Gray Marineengine is'accompliohed by1. reveroing the crankshaft rotation2. using separate dicks and gear train3. reversing the forward disk rotation4. reversing the bock plate

With Joe's clutch a d reverse geavothecrankshaft rotation o transmitted Cothe redUction gear ohaft through the

.

1. crankshaft driV'e gear extenoipn2. first reduction gear3. locked train gearing4. clutch and reverse gear unit

2 -5.

A

2-56. What happens when compressed air (100 psi)is admitted into the flexible tire of anairflex clutch while it rotates at,enginespe0.?1. The clutch moves out'of contact with

the engine flywheel'2. The clutch make:I-contact with the

engine flywheel,3. Friction blocks on the inner tired

surface make,contact with a clutch-drum

4. Friction bloCka on the inner tiresurface move out of contact with aclutch drum

2 -57' What is one of the adyentageo of fluiddrives over mechanicgl clutches?1. /lippage is completely eliminated2. No mechanical connection is needed

between the engine and the reductiongear)

3. Power loss is only 1 percent4. Driving fluid doeb not absorb power

loss

"

2-58. What function io served by the dog clutch 2-62. Suppose you boil the water in two

when it in used in addition to the containero, A and B. A io an open

friction clutch? container and exposed to atmospheric

1. Engagingait juot before engaging the/ pressure, whereas B io a cloned container

friction clutch speedo up the action in which the pressure io greater than

of the friction clutch the atmosphere. What in the,relationohip

2. Engaging it after the friction clutch 4. between the temperatures of the water

has equalized the speed of the two boiling in the containern?

nhafts prevents slipping and mini- 1. The water tempeuture in A is higher

sizes wear of the' rictionoclutch than that in D

3. Engaging it at the same time the 2. The water temperature in A in lower

friction clutch in,engaged provides than that fn D

for smoother transfer from one speed 3. The water temperature in A in 212° y,

to another which in the same an that in 13 \

4. Engaging it during and after engaging 4. The water temperature in A in 212° F.

the friction clutch helps to quicken which in greater than that in

the change from one speed to anotherand makes for greater smoothness of 2-63. What in the purpone(n) of the nuaerheater

operation furnace shown in the textbook fiihre

02-59. The reaction forcedeveloped by the forceof the water being moved astern by apropeller acts on what part of the pro-peller?1. The back2. The leading edge

S3. me root4. The face

2-60. Which of the following statements withregard to propellers in true?1. Direction of propeller thrust can

be changed on.some propellers bychanging the pitch of the blades

2. The number of blades on ship propellersvaries ',from two to four

3. Co., roll7lable pitch propellers are of

the Mingle casting type4. Left-hand helical propellers, as

viewe4 from astern, trn clockwiseto mov41 the ship forward

Learning Objective: Recognize the(our areas ation of the basic

steam cycles. Text ook Pages 49through 53.

2-61. The amouni.of latent heat required to"change boiling water to steam is the sameregardless of the pressure in the gener-ating container. .

tt,

5-2?

1. Raise the temperature of the maturatedsteam

2. Draw the saturated steam from thegenerating furnace

3. Raise the temperature of the feedwater without increasing prennure

4. Do each of the above

2-64. For which of the following reasons arenaval boilers designed to produce bothsaturated and superheated steam?1. Because superheated steam for propul-

sion in more efficient than saturatedsteam

2. Because most auxiliary machineryoperaten on saturated steam

3. Both 1 and 2 above

4. Because propulsion and auxiliarymachinery operate on saturated andsuperheated steam and frequentlyswitch from the use of one to theuse of the other

2-65. What energy conversion takCs place aftersteam enters the turbine of a oteam-driven ship?1, Heat energy to electrical energy2. Mechanical energy to heat energy

3. Heat energy to mechanical energy4. Electrical energy to heat energy

2-66. If your ship's main turbin stallation

is like that shown in text k figure

5-1, steam from the boilete4o expandedin the1. cruising turbine2. hl,gh- pressure turbine

3. slow- pressure turbine

4. cruising, high-pressure, and low-pressure turbines

22 0

.

Porgy itemo 2-67 through 2-70, refer tofigure 5-1 in your textbook.

2-67. In which port of the oteam cycle Jo airremoved from the condenoato?1. A2.

3. C4. D

2-68. The dotted linoo onelooing C and D Dhowthat tho deaerating tank belongs to which

'part° of the otoam cycle?1. Generation and feed2. Feed and condenoato

,3. Expanoion and generationCondenoato and expanoion

2-69. The deaerating tank in the oteam cycleio uoed for which of the Allowingpurpooeo?1. To remor any trapped oxygen or air

from the condenoate2. To preheat the water before it g000.

to the economizer3. To verve ao a otorage tank for

reocrve feed water and for ourpluo-condenooto

4. All the obovo

2-70. The condenoato from part C of the otoomcycle firot become° feed water in the1. economizer2. top section of the deaerating tank3. otorago ()action of the deaerating

tank4. piping between the main and b000tor

. feed pump()

2-/1. The diccharge preasure of a main feedpup diacharging to a boiler operettasat 600 poi lo approximately1. 55C poi2. 700 poi3. 750 poi4. 1,000 poi

2-72. Watpr io preheated in the oconotiter by1. heating it with a ouperhooter located

directly under tho economizer2. circulating it in tubeo ourrounded

by tho got= of combuotion3. mixing it with jeto of hot air that

are pumped into the economizer4. mixing it with hot water dioeharged

from the main feed piping oyotem

2-73. The main difference between the auxiliaryoteam cycle and the main nee= cycle iothat the auxiliary doco NOT include the

.22113

1. condenoer2. &lactating feed tank3. ouperheater4. economizer'

El

7Assignment 3

3Boiler°, Steam Turbine° and Reduction Gear°

Textbook Aseigntent: Chapter°, 6 and 7

Learning Objective: Identify majorcomponent° of naval boiler° andstate their functions. Textbookpage° 56 through 71.

z

3-1. The °teem drum of a boiler aerve° as allof the following except a1. reaervgir for the ateam generated in

the tube°2. °operator of moiature from the °team

%generated in the tube°3. .'otorage apace for boiler water which

is diatributed to downcomera4. separator of air from the °team

generated in the tube°

3-2. Which part° of a boiler function to'Pk distribute water equally to the generating

tubea?'

1. Steam drum and economizer2. Downcomera and economizer3. Water drum and sidewall hedder4. Sidewall tutie° and aidewell header

3-3. The generator tubes in a boiler are 1 to2 inches in diameter instead of 3 to 4inches becauao smaller tube° absorb morehjat from the hot gape° circulating aroundthem.

3-4. In addition to d&recting the flow of steamfrom the eidewell header to the °team drum,the tidewell generating tubes nerve to1. direct the flow of water from the

°team drum to the aidewell header2. protect the sidewall from the intense

heat in the furnace3. dietribute water equally to the down-

camera4. direct the flow of combuotion gases

around the economizer tubes

3-5. Downcomers are uced to direct the flow of,water from the steam drum into, the1. economizer2. water drum3. aidewell header4. water drum and sidewall header

222

3-6. Refractory material is uoed to line the°teal caning of d boiler furnace in orderto

1. prevent excepoive loaaeo of furnaceheat

2. help maintotAn high furnace temperatures.3._ protect the caning from the intense

heat in the furnace4. do all of the above

3-7. What boiler component utilize° heat fromcombuotion gat= to heat incoming feedwater?1: Air preheater

_2. Economizer3. Deaerating feed-heater4. Header

3-8. Finn on economizer tube° nerve to1. decrease the right of the tube°2. absorb the heat from combuotion gage°3. speed the flow of combuotion genes4. increase the capacity of the tubes to

hold steam

3-9. Each end of a horizontal superheater tubeis connected to a1. vertical superheater header2. horizontal superheater header3. vertical sidewall header4. horizontal aidewell header

3 -10. What type of atomizer is Most common anduoed on most older °hips?1. Return -flow 4

2. Straight-steam3. Steam- ssiat4. Str ght-through-flow

3-11. Which part or parta,of an air regioter ina burner assembly impart a whirling motionto inrualling air?1. Air doors2. Diffuner plate3. Air foila4. Air doors and diffuser plate

SO

3 -] v....1)08e of the tangential oloto in aoprayer plate are to1. form the cone ohaped spray .

2. break up the.oil into fine particles3. impart a rotational velocity to

the oil4. mix the fuel with air

3-19 The baoic typed of auxiliary boilero usedby the Navy include1. fire-tube boilero2. water-tube natural circulation

boilero3. water-tube forced circulati9n boilero4, all of the above

3-13. Fire-tube boilers have been replacedby 3-20water-,tube boilero on most naval shipsbecause1. fire-tube boilers have a higher

concentration of scale-forming salts 3-21.than water-tube boilers

2. fire-tube boilers are more difficultto examine than water-tube boilero

3. fire-tube boiltrs are not able to 3-22.meet the demand for rapid changes inload that water-tube boilers can

4. fire-tube boilers have more compli-cated construction than water-tube 3-23.boilers

3-14. The circulation of water in natural circu-lation boilers depends on the differencebetween the density of rising steam-freewater and the density of falling hot.waterand oteam.

3-24.3-15. "Water is made to run faster in accelerated

natural circulation boilers than in freenatural circulation boilers by1. wider nozzles of generating water

tubes2. tubes connecting steam drum to water

drum sloping at a steeper angle3. application of more heat4. an increased number of downcomers

3-16. Where are downcomers installed on accel.-erated natural circulation boilers?1. In the furnace area2. Between the steam drum and water

drums outside the furnace3. Between the sidewall tubes and inner

casing4. Between the economizer and the super-

heater

3-17. The superheater tubes in convection-type' superheaters are protected from the

radiant heat'of the furnace by1. ,baffles2. water screen tubes3. downcomers4. generating tubes

3-18. The steam from a pressure-fired boilerinstalled on a 1040-class destroyerescort is used exclusively for1. propelling the ship2. distilling sea water3. heating the crew's berthing spaces4. laundering

Boilers operating at 700 poi burn leoofuel for a given shaft horsepower than doboilero that operate at lower preooureo.

When working in"a fireroom aboard ohip)you should keep your shirtmleeveo rolleddown at all times.

Before lighting off a boiler you shouldremove some of the water from the econo-mizer by using the emergency feed pump.

You are preparing to put 0a boiler into

operation. Before lighting off the firotsaturated burner you should be oure toI blow down the gage glasses

purge the furnace

leave disconnected atomizers in place4. remove the atomizers from the regiotero

Which of the following safety precautionoapplies to the securing of a boiler?1. Closing_the openings to the furnace as

soon as the atomizers have been putout

2. Bringing the water level in the gageglass to the point where it showsthree-fourths full

3. Closing the master oil valve"after thefuel oil pump is securedS

A. Each of the above

Learning Objective: Recognize theprinciples of operation of naval steamturbines and identify major componentsand their functions. Textbook pages72 through 81.

3-25. In addition,, to direction of steam flow,in which way may turbine types be classi-fied?1. The way in which the steam makes the

turbine rotor rotate2. Type of staging and compounding of

steam pressure and velocity3. Division of steam flow4. All of the aboy ways

15

2 2a

Figure 3A.-Diagram of Hero's engine.

3-26. In figure 3A, the steam escaping fromthe nozzles causes the engine to1. remain stationary2. turn clockwise around point X3. turn counterclockwise around point X4. turn alternately clockwise and

counterclockwise around point X

3-27. Which of the following devices operatesmost nearly according to the impulseturbine principle?1. Hero's2. An elect ic fan3. A windmill4. A jet pump

3-28. What happens to the ste4 that passesthrough the steam nozzles of an impulseturbine?1. It loses pressure and2. It loses pressure and3. It gains pressure and4. It gains pressure and

gains velocityloses velocityloses velocitygains velocity

3-29. What happens to the energy in pressurizedsteam as it emerges from the nozzles ofan impulse turbine?1. Kinetic energy converts to potential

energy2. Potential energy converts to kinetic

energy3. Kinetic energy converts to thermal

a

energy4. Potential energy converts to mechanical

energy

3-30. How are the blades arranged in a velocity-compounded impulse turbine?1. Two or more rows of revolving blades

are followed by a like number of rowsof stationary jets

2. One row of stationary blades followseach two rows of revolving blades

3. Revolving and stationary blades areinstalled in alternate rows

4. Both revolving and stationary bladesare provided on each row

16

3-31. The function of the otationary bladed ina velocity-compOunded impuloe turbine ioto

1. increase the velocity of oteam2. direct the flow of oteam3. decrease the velocity of oteam4. increase oteam pressure without loss

in velocity

3-32. The efficiency of a single -stage impablaturbine is increased by adding1. rows of moving blades to the rotor

wheel2. simple impulse stages in the oame

casing3. either 1 or 2 above4. rows of fixed blades to the casing

3-33 A reaction turbine is driven by thereaction of the force required toincrease the velocity of steam as'itpasses through the nozzles.

3-34 The length of the blades of a reaction-type turbine is increased at each succeed-ing stage in order to accommodate the1. higher turbine speeds2. steam condensate3. increased steam pressure4. increased volume of,the steam

3-33. What happens. through each

1. It gains2. It gains3. It loses4. It loses

to the steam that passesstag& of-a reaction turbine?pressure and loses velocity.pressure and velocitypressure and velocitypt4ssure and gains velocity

3-36. To permit a turbine to expand and contracton its foundation, the turbine is usuallyinstalled by securing its1. forward end rigidly and allowing some

freedom of movement to the after end2. forward and after ends in separate

grooves Olowing each end to moveindependently

3. forward and after ends to a slidingsunken plate

4. after end rigidly and allowing somefreedom of movement to the forwardend

3-37. Which of the folowing metals is used inthe making of turbine casings and rotorsto enable them to withstand the effectsof superheated 700° F steam?1. Carbon steel2. Carbon molybdenum steel3. Cast irorf.4. Bronze

224/

3-38: Which bearings aro used in 'a propulsionturbine to carry the weight of the rotorand to maintain the proper radial clear-ance between the rotor and the caoiig?I. Ball or roller bearings2. Spherical - seated sleeve bearings3. Cylindrical sleeve bearings -4. Spherical-seated or cylindrical

sleeve bearings

3-39. Propeller thrust bearings and turbinethrust bearings differ chiefly in1. design2. size3. materials from which they are made4. function

3-40. A function of the turbine rotor-shaftglands is to prevent1. lubricating ail from leaking into

the turbine casing2. lubricating oil from leaking into

the engineroom3. steam from leaking out of the turbine

casing4. any of the above from happening

3-41. When carbon and Labyrinth packing areused in one turbine rotor-shaft gland,how are they arranged?1. Carbon packing is us in the high-

pressufe area and yrinth infthelow-pressure are.

2. Labyrinth packing is used in thehigh-pressure area and carbon packingis used in the low-pressure area

3. Carbon and labyrinth packing areused interchangeably

4. When temperatures are to go over650° F, only labyrinth packing isused

3-42. By what means are low pressure turbineglands sealed at all times to keep airfrom entering the condenser?.1. By passing auxiliary exhaust steam

to the glands2. By increasing the pressure inside the

steam chest3. By decreasing the temperature inside. the steam chest4. By lubricating the glands will low-

-,viscosity oil

3-43. In low pressure turbines, and gland seal-ing steam pressure is maintained atapproximately1. 0 to 1 psi2. 1/2 to 2 psi3. 2 to 3 psi4. 1/2 to 4 psi

Learning Objective: Recognize thecommon form of reduction gears usedin shipboard machinery. Textbook pages .

81 through 83.

3-44. Which type of double reduction gearing(if any) do moot auxiliary ships usefor main propulsion?1. Nested2. Articulated3. Locked train4. None

3-45. Wiat type of metal is used for the teethin the,ptnion gears of the main reductiongears?1. Bronze2. Cast steel3. Forged steel ,4. Copper-nickel

3-46. Bull gears are usually secured to theirshafts by means of1. spot welds2. keyo3. locking nuts4. keys and locking nuts

3-47. The base section of a bull gear casing isused for several purposes, one of whichis to support the1. main thrust bearing2. bearing housing for the intermediate

pinions3. bearing housing for the intermediate

gears4. bearing housing for the high ope

pinions

3-48. Which gears are used in transmittinmotion from a turbine to the shaft 9f acondensate pump and in reducing turbinespeed to pump speed?1. Pinion and single helical gear2. Two bevel gears3. Worm and worm wheel4. Pinion and double helicargear

17

225

ssv

Learning Objective: Recognize thecharacteristics and purposes oflubricating oils and greases usedin the Nally. Textbook pages 84 through87.

3-49. Which of the following 1.8 the beatdefinition of friction?

A1. Friction is the amount of pre:inure,

with which one surface is pressedagainst another surface

2. Friction is the amount of heatgenerated between two slidingsurfaces

3. Friction is the resistance that onesurface offers to its movement overanother surface

4. Friction is the ratio of the rough-ness of one surface to the roughnessof another surface

3-50. Under ideal conditions, what kind offriction occurs when a main shaft rotatesin a properly oiled main journal?1. Fluid friction between the molecules

of the oil and.the suspended foreignmatter in the oil

2. Fluid friction between. the moleculesof the oil and between the film ofoil on the shaft and the film onthe journal

3. Sliding friction between the mainshaft and the main journal

4. Rolling friction between the mainshaft and the main journal

3-51. If the correct lubricating oil is replacedby an oil of a higher viscosity, a bear-ing will be subject to1. increase in pressure and in operating

temperature2. increase in friction and in operating

temperature3. decrease in friction but increase in

operating temperature4'4. increase in friction but decrease in

operating temperature

3-52. Whefe are Zerk fittings used?1. On rotary water pumps2. On turbine bearings3. On lube oil pumps4. On bearings with a heavy load

3 -53. Which of the folloqing valve° io uacd toprevent excessive piteobure in.thecd1feed lines of a lube oil pump protem?1. Governor2. Throttlg3. Reducing4. Relief

3-54. How do you regulate the temperat rthe oil flowing around the tubes o_.,atube-in-shell type of oil cooler?1. By regulating the amount of oil flow-

ing around the tubes2. By regulating the amount of sea water

flowing through the bes3. By doing both of t e a..ve4. By regulating the

circulating around

3-55. 'ssume that you notice n su en; decideddrop in the pressure gage in the oil feedline to the turbine bearings. The ChiefMachinist's Mate will immediately orderyou to 0

1. slow down the engine until cressurebuilds- up.again

2. stop the engine3. deCiease the pressure in the co ,ling

, tubes4. increase the pressure in the cooling

tubes

3-56. Mineral lubricating oils can withstandthe effects of high temperatures and'speeds better than either animal orVegetable oil.

3-57. Assume that 60 clof a class 3 oil at a,temperature of 130° F require 3 minutesto pass through the Saybolt viscosimeter.Which of the following symbol numbers

.,would be used to designate the oil?1. 13002. 1803

3. 30034. 3180

3-58. Why does a,,2190TEP oil provide reductiongears more protection than a 2190 oil?1. It resists corrosion better2. It protects better against the effects ,

of water3. It can withstand heavier loads4. It does all of the above

3-59. What type of grease is used as a generalpurpose grease for light loads and ordi-nary operating temperatures?1. Graphite grease2. Soda soap grease1. Lime soap grease4. Lead oleate soap grease

18

226

3-60. Which of the following lubricating greasier)contains a (menial additive to preventmeting at high temperatpren?1. Lead oleate grease2. Extreme prenoure greaoe3. Graphite grease4. Oxidation inhibitor greaoe

Hard grades of greaoe are used for lubri-cation of part° used at1. high opeedo under light pressure2. medium opeedo under medium pressure3. plow speeds under hpavy pressure4. high opeedo under heavy pressure

3-61.

3-62. If a lubricating chart has not been Modeup for a certain unit of machinery Aboardship, you should determine the type oflube oil opecified lor the unit by con-ealting the manuface4pr's technicalmanual.

19

227

.

Assignment 4Auxiliary Machinery and Instruments, Pumps, Valves, and Piping

Textbook Assignment: Chapters 8, 9, and 10

Learning Objective: Identify thelocation and functions of shipboardauxiliary machinery and equipment.Textbook pages 89 through 99.

0-

44-1. ThS vapor compression refrigeration-system

is used on naval ships for which of thefollowing applications?,1: Refrigerated cargo2. Refrigerated ship's stores3. Ship's service store equipment4. All of the above

4-2. For Navy ships designed after 1950, thefreeze room and chill,rts are kept atwhich of the following te peratures?1. 0° F and 33° F, respectively2. -5° F and 20° F, respectively3. -10° F and 10° F, respectively4. -20° F and 5° F, respectively

4-3. The purpose of air. aboardnaval ships is to1. provide comfort for the crew 12. protect equipment from high tempera- .

tures3. increase personnel efficiency4. do all of the above

4-4.' In the vapor compression distilling plant,the source of energy used t heat seawater is1. steam2. boiling water3. electricity4. furnace gases

4-5. How is fresh water obtained from thevertical basket type of steam-operateddistilling plant?1. By vaporizing preheated feed water

over and over again and,then condens-ing the feed water vapdr

2. By using steam to boil sea water andthen condensing the fresh water vaporgiven off by the boiling sea water

3. By using combustion gases from aboiler furnace to boil feed water ina coil and then condensing the freshwater vapor glen off by the boiling'feed water

4. By using combustion gases froin aboiler furnace to boil sea water in a'coil and then condensing the freshwater vapor given off by the boilingseawater

4-6. When there are two soloshell double-effectevaporator plants aboard a destroyer,they are located in the aft engineroom.

4 -7 The two types of steering gear used bythe Navy are electromechanical andelectrohydraulic.

4-8 In which of the following respects iselectrohydraulic steering gear superior '

to electromechanical steering gear?1. Depend it and flexibility2. Saving' In weight and space occupied3. Less friction between moving parts

and quicker responses to movements ofthe steering wheel

4. All of the above respects

4T9. To meet Navy requirements, an anchorwindlase must be equipped with brakes and'a means of reversing direction.

4-10. The capstan shown in textbook figure 8-7is used for1. heaving-in on anchor chain2. paying-out on anchor chain3. heaving-in on heavy mooring lines4. lifting boats

) 22820

4. P

4-11. The three wings on the tubular-type ofoil purifier serve to

le keep the oil rotating at the speedof,the,bowl A

2. collect the sediment or other impuri-ties

3. separate the oil into three layers4. help accelerate the rotation of the

bowl

4-12. Aboard Navy ships, compressed air is usedfobX. charging and firing torpedos2. starting diesel engines3. operating pneumatic tools4. all of the above

4-13. Which type of air compressor is used mostin the Navy?

Learning Objective: Recognize theprinciples of operation and uses ofengineering measuring instruments.Textbook pilges 100 through 115.4

t4-18. The gages and other measuring instrumentsin a shipboard engineering plant enableoperating personnel to1. determine operating efficienOy of,

)he plant' 2. bbtain data for records and reports

3. detect abnormal operating conditionsin a system

4. go all the above

1. Centrifugal, turbine-drive2. Reciprocating, electric-drive3. Rotary, diesel-drive In items 4-19 through 4-4, select the type of4. Rotary, electric-drive measuring instrument from column B that provides

the kind' measurement in column A4-14. Medium pressure air compressors are those

with discharge pressures that rangebetween -*

1. 51 and 100 psi2. 101 and 150 psi3. 151 and 1,000 psi4. 1,001 and 1,200 psi

4-15. If pressure fails in the high-pr Aburetank of a direct plunger lift elevator,what devices check the elevator's fall?1. Mechanical locks2. Guide rails3. Special control valves4. Automatic quick closing valves in the

oil line

4-16. The speed of the gypsy head of an electro-hydraulic winch is controlled b71. regulating the operating curtsnt of

its a-c motor2. regulating the operating voltage of

its a-c motor3. adjusting the stroke of its hydraulic

pump4z adjusting the clearance between the

friction surfaces of its brake

4-17. The galley equipment aboard modern navalships include all of the following except

A. Measurements

4-19. Height in inches

4-20. Turns per minute

4-21. Total gallons

4 -22. Pounds per squareinch

B. Instruments

1. Pressure gages

2- Liquid levelindicators

3. Revolutioncounters

4. Fluid flowmeters

4-23. On what principle does a Bowdon tubegage work?1. Volume changes in a str ght elastic

tube tend to expand the tube2. Volume changes in a coi ed elastic

tube tend to collapse t3. Pressdre in a straight elastic tube

tends to bend the tube4. Pressure in a curved elastic tube

tends to straighten the tube

4-24. The tube in a simplex Bourdon tube gageis connected to a pressure source andto an indicating mechanism. The endsof the tube are fastened to a

stationary base and a connecting link,respectivelystationary base and a connectinglever, respectivelyconnecting link and a connectingAver, respectivelymovement support and a gear sector,respectively

1. toasters 1.

2. mixing machines3. extractors 2.

4. refrigerators3.

4.

229

21

6

/4-25. ,,When the press a being measured with the

gage shown irr,t ctbook figure 9-2 isincreased, the Lnkage end of the Bourdontube has a tend icy to move so as tocause the

gear sector teeth to disengage frome pinion zar"

2. to bect ae more curved.3. ter to tun cl4, p er to tun c unterclockwise

4-26. Which the following measurements istaken w th a simplex Bourdon ttiBt gage?1. Depth of water in a ship's fresh

water tanks2. Amount of fuel oil flowing through a

valve3. Pressure in a cOmpiessed air system4. Pressure drop between inlet and outlet

sides of a lube oil strainer

4-27. 'The duplex Bourdon tube gage .can be ,

thought of as two simplex gages in ong.However, the duplex gage ups a'single1. gear mechanism2. dial3. pointer4. tube

4-28. The type of gage whose.indicating mecha-nism is shown in figure 9-6 of yourtextbook is used for measuringkressuresthat range between1. , 0 and 15 psi gage2. 16 and 30 psi gage3. 31 and 50 psi gage4. 51 and 100 psi gage

4-29. Which type of instrument is best formeasuring air pressure in the spacebetween the inner and outer casings ofa boiler?1. Duplex Bourdon tube gate2. Compound Bourdon tube gage3. Bellows gage4. Diaphragm gage

4 -30.' Which of the following parts is theessential element of a manometer?1. Bellows2. Bimetallic strip3. Diaphragm-covered chamber4. Liquid-filled U-tube

4-31. Most liquid-in-glass thermometers -ins pboard engineering plants are filled

1. hyl alcohol2. be ine

3. mercurydyed water

4 -32. The element of a bimetallic dial thermom-%eter responds to a rise in temperatureby1. expanding outward, thereby 'leasing

against the wall of the retainingtube

2. unwinding, thereby twisting the freeend of the element

3. contracting lengthwise, thereby pull-ing the free end of the elementinward

4. expanding lengthwise, thereby, push-ing the free end of the elemdhtoutward

4-33. Which component is the sensing elementof a distant-reading mercury - filledthermometer?1. Mercury bulb2. Capillary tubing3. Flexible cable4. Bourdon-tube pressure gage

'4-34. Which of the following types of thermom-eters indicates temperature change asa result of pressure-volume changes?1. Bimetallic2. liistant-reading3. Liquid-in-glass4. Pyrometers

ts`

4-35. The metals that makeup the actuatirikielement of a pYrometar tespond to arise in temperature by converting heatenergy into1. chemical energy,2. luminous energy »3. electrical energy4. mechanical energy

..

36. In thestatic head gaging system, the

'..) amount of liquid in a tank is determinedby means of a-direct measurement and '

conversion to another unit of measure. t,

Which direct measurement and conversionis used to determine the amount of oilin a fuel oil storage tank?1. The depth of oil is measured directly

in feet and is converted to gallonsof oil'

2. The pressure of the oil at the tankbottom is measured in inches of

-..

mercury and the pressure is convertedto.gallons of oil .

3. The temperature of the oil at thetank is measured, directly in degreesand the temperature is converted togallons of oil

4. The volume is measured directly incubic feet and volume is converted7 to gallons of oil

22

230,

FIRST READING

Figure 4A.-4ound reading

4-37. The two meter readings of figure 4A weretaken 1 hour apart. How much liquid wasmeasured during the hour?1. 699 gal2. 869 gal3. 938 gal4. 1,129 gal

4-38. Which quantity is measured directly withicYrevolution counter?

Rotational speed of a turbine2. Rate at which oil flows through a

r pipe3. Total number of turns made by a shaft4. Rotational speed of a pump

4-39. What instrument is commonly used tomeasure the rotational speed of a shaft?1. Manometer2. Tachometer3, Hydrometer

Barometer

4-40. Withhich kind of tachom f do youmake direc't contact w a LacABgshaft to obtain instantaneoug vAITOof speed on a dial face?1. Centrifugal2. Chronometric3. Both 1 and 2 are correct4. Resonant

23

SECOND READING

registers.

4-41. Which of the followin& types of tachom-eters an be used to asure the speedof a rotor when there is no access toits rotating shaft?1. Centrifugal2. Chronometric3. Resonant4. Any of the above

4-42. Which type of tachometer is used to t

obtain speed readings continuously insteadof intermittently?1. Portable centrifugal2. Portable chronometric3. Revolution counter4. Resonant reed tachometer

4-43. The superheater temperature alarm on aboiler is actuated by an electric micro-switch. The force that throws themicroswitch is provided by a1. pressure that is exerted by a rise in

temperature2. cantilever arm that moves when mercury

P expands in a spiralzwound Bourdontube

3. revolving gear that meshes with themicroswitch

4. torque that is exerted when a bimetal-lic element is heated -

4-44.

231

Which signal is an indication of low ,

pressure at the bearing located farthestfrom the lube oil, pump?1. Steady red light on a control board2. Ringing bell or loud siren3. Intermittent buzzing sound4. White light flashing on and off

4

e throttleman warned if he triesto open the ahead throttle valve when theengine ordef telegraph indicates "astern"?1. By smoke coming deankfro;the pert.,

scope smoke indicator2. By a flashing light on the throttle-

board3. By a loud signal coming from the

wrong direction alarm4. By a burting sound coming, from the

static head gaging system Itg

Learning Objective: Identify someprinciples of pump operation andspecify the ways of classifying pumps,giving essential construction featuresof different components. Textbookpages 116 through 123.

4-46. What is the name for a device which isle to move a fly frem one place to

any her through the use of an Tmernalpo source to Apply a force to theflui1. or2. urbine3. Pump .

4. Valve

4-47: Pumps supply the sea water in a ship'sfiremain system. ValvesAn the systemfurnish the means of controlling'ihe

directidh that .the sea water flows A2. amount of seawater flowing3. pressure of the set water4. direction of flaw, amount, and pres-

sure of "he sea' water

4-48. Which of the following pumps is classi-.fled according to,the- type of movement,that causes it to pump?1. Variable stroke pump2. Positive displacement pump3. Self-priming pump4. Jet pump

4-49. Which of the following pairs of wordsrefer to the same end of a pump?1. Power end and fluid end2. Liquid end and pump end3. Power end and pump end.4. Pump end and Ateam'end

4-50. Aboard ship, you might refer to the powerenl of a fireroom pump drivetkby anauxiliary turbine as the1. rotorend2.. turbine end3. impulse end

r 4. steam -end

gV24

4-51. In which, pump is the Movement of fluid .

due to a plunger that moves up and downinside a cylinder?1'. Rotary2. Reciprocating3. Catrifugal4. Propeller

4-52. Why, are reciprocating pumps used foremergency feed water pumps on navalvessels?1. They are easy to operate2., The are reliable starters under cold

conditions3. They can be started safely even by

personnel having little experience4. Al) of the above reasons

Figure O.-Double-acting pump.

4-53. In the pump'shown in figure 4B, fluid isdischarged on the dowdAtroke'through

° 1. valve B2. vafve D "..

Valvds B and D4. valves C and 'D

4-54, How do the valves move when piston P inthe pump shqr in figure 4B moves upward?

u 1. Valves A and C close; valves B and Dopen

2. Valves A and D open; valves B and Cclose

I- Valves A and \p close; -valves B and C-open

4. Valves A aqd open; valves .0 and D\close

'232

zb

STEAM CHEST

Figure 4C.-Operatingprinciple of D-phaped

slide valve of a reciprocating pump.

4-55. The D-valve in the pump, figure 4C ismoved up and down by the1. pressure in the steam chest2. piston rod through a mechanical

linkage3. movement of exhaust steam through the

cylinder ports4. difference in pressure betwejk the

upper, and lower halves of the steamchest

' 4-56. Aftei- first closing the throttle in theprocess of securingaoreciprocating pump,

the next step you take is to1. close the exhaust valve2. cloSe theralves in the discharge

lines3. open the drain valveh

ft

4. close the valves in the suction line

4-57. The movement that causes a variablestroke pump to actually pump and by whichthe pump is classified

is brought aboutby

1. a tilting block rotating inside acylinder

2. pistons reciprocating inside cylinders3. propellers rotating inside cylinders4. an impeller rotating inside a casing

4-58. The of a aterbury variablestroke pum is determined by they1. size of the cylinder2. tilt of the angle plate'3. speed of the motor4. direction of oil flow

4-59. Which condition'eiiiits when the tiltingbox is at right angles to the drive shaftwhile the pump is rotating?1. The pistons reciprocate2. Liquid is pumped3. No liquid is pumped4.. Power is

transmitted hydraulically

A

8

Figura 40.-Simplo goar pump.

4-60. Aasame that the gear pump of figure4D...isused for lubricating oil service. Nowdoes the oil pass through the pump?

1. 011 moves into the pump throughsuction side A, passes around thegears in,the spaces between the pumpcase and he gear teeth and dischargesthrough ditlet B

2. Oil moves into the pump throughsuction side A, passes through tE. twogears, and discharges

through out-let B

3. Oil moves into the pump throughsyction side B, passes around thegears in the spaces between pumpcase and the gear teeth, an4 dis-charges through outlet A

4. Oil moves into the pump throughsuction side B, passes thrpugh thetwo gears, and discharges

throughoutlet A

4-61. Positive displacementpumps include allof the following except

1. Screw2. Reciprocating3. Centrifugal4. Variable stroke

L

25

233

$

Assignment 5Pumpo, .Valveo; Piing, and Shipboard Electrical Equipment

TentbOok Apoignment: Chaptoro 10 and 11

Learning Objeative: Iden$,ify the

. location and functions of ohipboardauxiliary machinery and equipment.Textbook pagan 122 through 126.

5-1., The,,ocroc pump io similar to the gear pump

" in that both are1. pooitive diopladement rotary pumpo

2. variable capacity pumps

3. pooitive dioplacement centrifugal

pumpo4. non -self- priming pump°

5-2. Fluid entering the inlet pipe of a con-

trifpgal pump in firot,directed into the

1. center of the cooing,

2. ,vane o of the impeller

3. opac6 between the impeller vaned and

, thd cooing

4. volute diffuoer

5-3. What precaution muot be taken in the

inntallatipn of a centrifugal pump to

enoure ffilt it Will become primed hen

its lake pipeln open?

1. e intake pipe only in above the

urface of the liquid to be pumped

2. The intake pipe only in below the our-

face of the liquid to be pumped

3. The entire pump io above the'ourface

of the liquid to be pumpedThe entire pump in below the Surface

of the liquid to be pumped

5-4. A propeller pump pueheo liquid in a

direction perpendicular to the ohaft.

5-5. Which feature of jet pump::: makeo them

different from all Other pumpo claonified

acqording to the type of movement causing

'the pumping action?1. HigH auction lift

2. No moving parts

3. Self priming4. Positive displacement

4.

5-6. Jet pumps are Clapp/fled ao ejectors or

eductorn deco dim to whethetooteam orvoter io used to entr

'lin and move fluido.

ATMOSPHERICPRESSURE

E

Figure 5A

5-7. Refer tq'f/gure 5A. Why in pumping actionm4ablid,heti after °team lower° the pren-

26

23 i

sure'in C by forcing fluid into E?

1. Velocity increase at B drawn fluid

from A and diochargeo it through ,B

2. Pressure difference between candatmoopheee lifts fluid /Tao C and

through A

3. PresstA difference between C and theatmosphere lifts fluid into C and

through E44Velocity increase at B draws fl

from A and discharges it throu

5-0. On new combatant nhipo, the primary meannof dewatoring comparCmontn through thedrainage ayatem are1. fire and blip pump°2. fixed-type cOuctor°3. centrifugal tiro pumpa4. Watorbury variable-volume pump° ,

5-9. If a conotant-pronouro pump governor inattached to a gear pump, the governor inconnected to-the1. driving gear2. driven guar3. suction lino4. diochargo line

Learning Objective: Identify thevarious kind° and type° of chipboardvalvoo, including constructionfeature°, their location°, andfunctiono. Textbook page° 127 through134.

tJ

5-10. Refer tp textbook figure 10-14. Whichparto of the globe valve move when thehandwheel in turned counterelockwioe?1. Stem and dick2. Gland and flange3. Bonnet and bushing4. Packing and otop ring

5-11. The special dooign of back °eating valvedmakeo it p000ible to operate them fullyopened with no leakage pant the packing.

5-12. Fluid io permitted to flow through thebody of a globe otop valve by turningthe handwheel in the direction which willcause the1. dick to lift off the valve neat2. dick to fit tightly againot the valve

coat3, stem to pull away from the packing4. stem to make contact with the packing

gland

5-13. In which way doe° a gate valve differ froma globe valve?1. Path of the fluid through the gate

valve in straight, through the gI'obevalve the path in not straight

2. Flow in regulated by degree° throughthe gate v lve but not through theglobe valv

3. The gate alvo workn well ao a throttle.valve, the glObe valve doeol.not

4. The gate valve in uped in, fuel linenonly, the 'globe valve in water linen

5-14. What tattoo place inolde /cho body of aplug wave when tho handle io turned toopen tho valvo?1. A dick lift° oft its °eating ourface2. A ball-ohaped piece float° off a

owning ring3. 4 poo0Ogovay in an othorwioo solid

piece linen up with the porto in thevalve body

4. A wedgo-ohaped piece ri000 to createan opening in the parmageway throughthe valve body

Tho plug valv; may be uped ao a1. throttle valve2. aoloctqr valve3. neodlo valve4.. chock valve

5-16. What typo of valve in wed in a lino/ whore the flow of fluid through an open-ing cunt bo regulated gradually andexactly?1. Pioton2. Needle3. Gate4. Globe

5-17. You can rortii; a fully opened butterfly-valve to its fully cloned pooition by1. doprepoing a pushbutton2. turning the handle to the opPIPoite

pooition3. lifting up on the handle4. turning the handle ono-fourth a turn

5-18. The owing check valve opono only when the1. inlet pm:lour() in greater than outlet

'preonure2. outlet pronnuro in greater than inlet

prepoure1. inlet prepoure in greater than spring

tenoion4. outlet prennure in greater than opting

tenoion

5-19. Whethof a ollap-check valve act° ao a otopvalve or ao a check valve depend° on the1. pooition of the control lover2. direction of flow3. typo of dick inotalled4. pooition of the stem

5,-20. The double-poppet throttle valve inactuated by1. manual force and power from an

electric motor/-

2. mapUal force and power from a hydraulicmotor

3.. steam preooure within the valve andmanual force

4. oteam prenoure within the valve andpower from a hydraulic motor"

,1

5-21. IA rol(of valvo lo'a typo of sure-control valve that io docti6 d to openautomitically when lino projeuro lo toohigh.

5-22. Uhothor a relief valve iD of the dicktypo or ball type, it lo kept eloped bythe

1. compreoolon of a °tool spring2. woight of ito valvo body3. annual forco with which ito stem lo

turned4. reactive force opposing the manual

force uped to turn its stem

5-23. Reducing valvoo uoed in roduced proaaurelino° aboard chip are deolgned to1. prevent damage to the lineo due to

(=cooly° preaoure2. keep operating propoure oqual to

supply prepoure3. vary operating proof:Jure according

to demand4. provide a °toady proof:Jure lower than

the supply proof:Jure

5-24. Uhat is one of the factor° that the opera-tion of a reducing valve depend° upon?1. The valve maintains outlet prepourn

and inlet prof:Jour° in equilibrium2. The valve maintain° outlet prof:Jour°

at one-half the inlet proof:Jure3. The inlet preaaure controls the rate

at which outlet oteam woe° throUghthe valve

4. The outlet proof:Jure controlo.the

rate at which inlet oteam paopeothrough the valve

5-25. A relief valve to never installed ac asafety ualve on the oteam drum of aboiler. Why?1. It will not remain open long enough

for blowdown to occur2. It will not pop ate °pacified prep-

pure3. It will not clooe tightly without

chattering nor remain- closed longenough after °eating

4. It io not installed because of allthe above reaoono

Learning Objeetivo: Delineatechipboard piping, including pipedefinition°, pipe cntOrialo, pipefitting°, socket° and packing,°trainer°, otcam trope, and drain°.Textbook page° 135 through 141.

5-26. Pipe deoignationo that refer to the wallthickn000 on the pipe include1. otandard2. extra otrong3. double extra otrong4. all of the above

5-27. If the nominal ID of a auble extraotrong pipe lo 7 infheo, ito actual ID Jo1. leo° than the actual ID of a 7-inch

extra otrong pipemore than the actual ID of a 7-inchextra otrong pipe

3. more than the actual ID of a 7-inchotandard pipe

4. more than 7 inches

k5-28. The °ire of tubing lo generally expressedin term° of its1. actual inside diameter2. actual inside circumference3. nominal outoide diameter4. nominal outoide circumference

5-29. Steam and fuel OVfitOMP i.boardchip are made of1. °tea2. copper3. braoo4. copper-nickel alloy

5-30. What type of oteel tubing io uguallyused for high-prpooure, high-te eraturetiteam cervico?1. SeaMleao carbon steel2. Molybdenum alloy oteel3. Chromium alloy steel4. Welded carbon steel

5-31. The composition of the gaoket material°elected for use in a piping oyotemdepends upon all of the following except

temperatures to which the fluidcarried in the system will beoubjected

2. prof:mum° to which the fluid carriedin the oyotem will be oubjected

3. kind of fluid carried in the system4. number of atrainero installed in the

oyatem .

2.3 p

28

5-32. On naval veoosflo, condensate io removedfrom steam lnea by means of1. mechaAical atom crape2. thermeotatic oteam trapo3. impuloe oteam trapo4. drains and mechanical, thermootatic,

and impulse steam traps

Learning Objective: Recognize theinherent hazards of electricityand °beery° all oafety procautionowhen working with or near electricalayotems and equipment. Textbook pages

142 through 154.

5-33. Which of the following oubotancen offerothe moot reolotance to electric current?1. Iron2. Mica3. Aluminum4. Copper

5-34. The rate at which a current paoaenthrough a lighting circuit is measured in

'1. watto2. volta3 ohms 44z

4. amperes

5-35. A unit of electrical reniatance in the1. watp2. ogir

3. ampere4. volt

5-36. Anaume that a soldering iron is rated at100 watts. This information tells youabout the1. power consumed by the iron2. realatance of the iron3. 'emf of the iron4. rate at which current flows through

the iron

5-37. A shipboard generator operates at greatestefficiency lallen operating1. in eerier, with other generators of

same rated output2. at 1$11 rated output3. at Yerioda of minimum power demand4. with batteries fully charged

5-38 The rotatiqiRmember of a d-c generator isusually called the1. armature2. yoke3. field winding4. rotor

5-39. What io the difference between the gyrate=for delivering current from the a-cgenerator and from the d-c generator?1. In the d-c generator, current flowo

from the commutator to olip ringoto the circuit; in the a-c generator,it flows from the otator to bruoheoto the circuit

2. In the d-c generator, current flowofrom the rotor to atator to thecircuit; in the a-c generator, itflowo from the rotor to the circuit

3. In the d-c generator, current flowafrom the commutator to bruoheo tothe circuit; in the a-c generator,it flown from the otator to thecircuit

4. In the d-c generator, current flownfrom thealip rings to the bruahecto the circuit; in the a-c generator,it flown from the bruaheo to therotor to the circuit

5-40. Revolving-field generators are superiorto revolving-armature generatora in thatthey1. have their load current from the

atator connected to the externalcircuit without the uoe of slip rings

2. need only two clip ring') to supplyexcitation to the revolving field

3. do not have their atator windingssubjected to mechanical stressed due,to centrifugal'forces

4. have all the above features

5-41 What provision Jo made to prevent a high-speed turbine-driven alternator fromoverheating?1. A forced ventilation system circulates

air through the stator and rotor2. The alternator is used in conjunction

with others and automatically goesoff when it becomes warm

3. A heat-limiting Overnor controls thetemperature

4. The alternator parte are encased in ametal structure that is surrounded bycold water

5-42.' What is the source of energy for theturbines that drive a ship's servicegenerators?1. Saturated steam2. Superheated steam3. Diesel engines4. Batteries t

23729

5-43. One °pacification that all ohipo oervicegenerator° cunt meet Jo that they1. oupply at leaot 600 volto of elec-

tricity2. operate at a conotant °peed3. be able to run indefinitely without

shutdown4. oupply alternating and direct current

to ohipo circuito

5-44. Why are emergency generators aboard Navyohipo dieoel driven rather than turbinedriven?1. Dieoel engine° can generate tore

power than turbine°2. Dieoel engines can °tart faster than

turbine°3. Dieoel engine° are copier to operate.

than turbine°4. There io leo° danger.e4 fireo from

dieoel engine° than from turbines

5-45. The control switchboard on a destroyerhao inotrumento and control° for paral-leling the forward and after ohip'soervice generator° and for equalizingthe load between them.

5-46. The automatic voltage regulator maintainaconotant voltage during load change byvarying1. armature reoiotance2. field excitation3. generator opeed4. governor °peed

5-47. Switchboards on Navy ohipo are providedwith fuses instead of automatic trippingcircuit breakers to protect againstvoltage failure.

5-48. Which of the followingcause an ,a-c generatorto trip?1. Gun fire2. Power reversal3.4 Short circuit in a4. Short circuit in a

troubles willcircuit breaker

lighting circuitfresh water pump

5-49. Emergency generators provide electricpower to1. emergency lighting 4

2. limited lighting and vital auxiliaries3. limited auxiliaries4. fireroom auxiliaries

30

238

5-50. What io used to oupply (1...c power tothe d-c loado on the new ohipo thathave a-c power planto?1. Rectifier°2. Motor generator°3. D-c generatoro4. Emergency generator°

5-51. What device in a ohipboard electricaloyotem will operate when power io ouddenlyapplied to a gun mount and to the anchorwindlaoo at the-oame time?1. Circuit breaker2. Rheootat3. Voltage regulator.4. Emergency generator

5-52. Although °team Jo readily availableaboard moot °hip° to drive auxiliarymachinery, electric power ie uoed formoot equipment located outoide themachinery °paces. Electric cable iosuperior to °team piping for transmittingpower because it io1. more eaoily controlled, leoo eaoily

damaged, and more durable2. more durable, more eaoily repaired,

and more convenient3. less eaoily damaged, Gofer, and more

easily controlled4. more eaoily controlled, Gofer, and

more convenient

5-53. Which of the following piecea of equip-ment may be equipped with electricbroken?1. Anchor windlass2. Switchboards3. Generators4. Auxiliary pumps

5-54. Shipboard motor controllers are used for1. starting and stopping motors2. increasing and decreasing motor

speeds3. reversing the direction of rotating

motor shafts4. all the above purposes

5-55. The presence of salt water in the elec-trolyte of a battery can set up achemical reaction that is damagng to the 1

Battery. 4

5-56. Assume that you are assigned to a shiploboat as boat engineer. If you see thebowhook poudding on a steel bolt with asteel hammer in the vicinity of thebattery compartment, you should stop himimmediately in order to prevent1. damage to the battery case2. serious inidry from spilled electro-

lyte

3. electrical shock4. a possible battery explosion

5-57. The roloy-oporoted bottle lantorn in onemergency lighting ,circuit auto-matically whon theI. emergency switchboard is energized2. relay Jo connected to the circuit3. power to the circuit Jo phut off4. switchboard emergency circuit is

clooed

5-58. Rand (battle) lanterns installed through-out the ship that pro not connected torelays are used for1. explooion proof light when needed in

newly opeRld voids2. nocesoary lighting when shifting

generators3. Droop not covered by the lighting

distribution (*Totem4. emergency use only

5-59. Portable power tools in use on Navy shipsare provided with three conductors, thethird conductor is to1. provide heavier loads for heavier

work2. protect operators from shock3. permit reversing of dud-tool4. provide emergency service if one of

the conductors is damaged

5-60. Normally, electric current for the lightsin a ship's machinery spaces is conveyedby power distribution system,

5-61. Power and lighting distribution (*lot=vary in that the1. oyotems have different power sources2. over diotribution systems carry

h her voltages3. power diotribution systems are more

n oroua4: ighting diotribution oyotemo have

larger cobloo

5-62. If o ohipio service generators furnishcurrent at 445 volts, what devices areused to atop down the voltage to operate110- to 120-volt equipment?1. Rheostats2. Controllers3. Transformers4. Voltage regulotora

5-63. Only Electrician'o Mateo or I. C. Elec-triciano ohould topoir electrical equip-ment aboard a Arlo.

5-64. You are repairing a motor-driven pump.The motor circuit contains o switch.You will be observing electrical safetyprecautions' when you have an electrician1. disconnect the motor from the circuit

by opening the switch2. attach a warning tag to the switch3. connect the motor to the circuit by

closing the switch after the repairwork is done

4. do all the above

31

239

It

Assignment 6Internal Combustion EnAineo and Engineering Watches

Textbook Asoignment: Chapters 12 and 13

Learning objective: Recognize the

ibaoic principles of internal com-

bustion engines. Textbook pages156 through 158.

.6-1. An internal combustion engine converts1. thermal energy to mechanical energy

through the use of steam2. mechanical energy to thermal energy

through the burning of fuel incylinders

3. thermal energy to mechanical energythrough the burning of a fuel-airmixture in cylinders

4. mechanical energy to thermal energythrough the use of steam

6-2. Combustion takes place in (A) a dieselengine and (B) a gasoline engine as aresult of ignition by1. expansion of compressed gases in A and

by a spark in B2. heat of compression in A and by a spark

in B3. a spark in A and by heat of compression

in B4. a spark in A and by expansion of

compressed gases in B

6-3. The one-way distance a piston travelsbetween its upper and lower limits oftravel in a cylinder is referred to as a1,7cycl

at ke

3. s roke-cycle4. revolution

6-4. During the intake stroke of a piston in a4-stroke-cycle diesel engine, the pistonmoves downward and draws a charge of airinto the cylinder through open intakevalves while exhaust valves remain closed.

.10

6-5. In the operation of a gasoline engine,the force that puoheo the piston downward /?

io the1. compression of fuel-air mixture2. intake of fuel-air mixture3. expansion of burning gapes4. removal of burned [poen

6-6. During which of the following pistonotrokeo is power furnished to the crank-shaft by the piston?1. Intake, compression, power, and

exhaust2. Intake, compression, and power3. Compression and power4. Power

6-7. Which of the following events in theoperating cycle of a diesel engine doesnot take place in the operating cycle ofa gasoline engine?1. Injection of fuel2. Compression of air3. Expanoion of gases4. Removal of burned gases

6-8. With respect to which factor must 2-stroke-cycle diesel engines differ from 4-stroke-cycle diesel engines?1. Number of pistons2. Piston arrangement A

3. Number of piston strokes in a completecycle

4. Distance a piston travels during astroke

6-9. When the piston nears the bottom of thepower stroke in the 2-stroke-cycle engine,what is forced through the cylinder intakeports?1. Fuel oil2. Scavenging air3. Lubricating oil4. Cooling water

2i032

6-10. Which of tho'following reasons partiallyaccounts for the failure of a 2-atroke-cycle engine to produce twice the powerof a 4- stroke -cycle engine of the camealoe?1. Some power developeq, the 2-atroke-

cycle engine io used to force airC) into each cylinder

2. Lean than all the combuotion,ganeaare scavenged from each cylinder ofthe 2-atroke-cycle engine

3. For a given air-fuel mixture, leasfuel and air enter the cylinders ofthe 2-atroke-cycle engine

1!, 4. Any of the above reasons

Learning Objeei,ive: Identify theAlain componentortbe.dieuel.crigine

indicate the r fpnctiono. fOXtbookpages 159 through 164.

6-11. The combustion chamber of a one-cylinderdiesel engine io sealed off from thecrankdaae by1. a piston and its rings2. an exhaust valve and an intake valve3. a piston and an exhaust valve4. a piston and an intake valve

6-12. The part of a diesel engine used tochange rotary motion to intermittentreciprocating motion is the1. crankshaft2. driveshaft3. bearing4. camshaft.

Figure 6A

6-13. Which letter of figure 6A refers to thepart of a can that io known ao the camflat?1. A2. B

3. C4. D

6-14. The exhaust valvea in the cylinders of adiesel engine are opened by action of the1. crankshaft2. connecting rode3. valve apring4. camshaft I

6-15. The motion of the cam in a diesel engineis tranamitted to the exhaust valves-bythe action of the1. rocker arm and the bridge2. rocker lever shaft and the bridge3. rocker. lever shaft and the cam. roller4. rocker arm and valve guide

6-16. In a 2.-stroke-cycle engine, how many timesdoes the camshaft turn as the crankshaftmakes 16 turns?1. 8

2. 163. 32

4. 64

6-17. The speed of a reciprocating engine isthe same as the speed of the engine'scrankshaft. Relative to engine speed,how fast does the camshaft of an

8-cylinder, 4-stroke-cycle engine turn?1. One-eighth as fast2. One-fourth as fast3. One-half as fast4. Twice as fat

6-18. During the intake stroke of a 4-stroke-cycle engine, air is forced into thecylinder by

- 1. atmospheric pressure2. the pressure of exhaust gases3. rotary blowers4. unit injector

6-19 Describp the changes in the temperaturearid volume of the air in a cylinder of areciprocating engine during the compres-sion. stroke of a piston.1. Temperature increases; volume

decreases2. Both temperature and volume increase3. Temperature detreases; volume .

increases4. Both temperature and votume decrease

24133

4

6-20. Which-of the following compression rttios 6-26.io typical of diesel engines?1. 4:12. 5:13. 10:14. 5:1

Itemsauppl

6-21 through 6-23 refer to the fuel""ayotem of texthlbok figure .

6-21. Which c mponent functions to meter,pressurize, and atomize the fuel?1. Fuel pump2. Inlet manifold3. Injector4. Outlet manifold

6-22. Which component &there for the last timethe fuel that enters the combustionchamber of the engine?1. Primary filter2. Secondary filter3. Fuel pump4. Injector

6-23. The speed of the engine is controlled byvarying the amount of fuel in ected intothe cylinders of the engine. The fuelcharge is varied by1. rotating the plungers in he unit

injectors t.2. enlarging the holes in the injector

nozzleser47

3. increasing the capacity of the fuelpump

4. changing the compression ratio of theengine

6-24. Which of the following types of actionwould most likely be necessary if thelubrication system of an internal com-bustion engine should fail?1. Main oil line should be flushed out2. Oil pYessure gage should be replaced3. Camshaft gear and crankshoft gear

should be cleaned4. Engine should be completely overhauled

6-25. The engine should be secured until thetrouble is located and corrected if1. the oil pressure should drop to lower

than normal2. the temperature"of the oil should

rise abnormally-3. either 1 or 2 above should occur4. the oil strainer should become clogged

Fresh water and salt Water are both usedas coolinwagents in a type of dieselengine. In this engine the function ofthe sea water is to1. cool the fresh water after it cir-

culates through the engine2. replace the fresh water when its

temperaturF:exceeds 212° F3. supplement the supply of fresh water

lost due to evaporation4. sloW,down the cooling process when

higher engine operating temperaturesare desired

6-27. How long may the electric startermotor for a diesel engine beoperated?1. 30 to 0 .seconds

2. 30 se onds3. 2 to minutes4. 3 to 5 minutes

34

Learning Objective: Identify themain components of the gasolineengine and indicate their functions.Textbook pages 165 through 169.

6-28. In a gasoline engine carburetor themixture ratio is the number of1. pounds of gasoline vapor mixed with

each pound of air2. cubic feet of air mixed with each

cubic foot of gasoline vapor3. pounds of air mixed with each pound

of gasoline vapor4. cubic feet of gasoline, vapor mixed

with each cubic foot of air

6-29 Which of_the components of a gasolineengine ignition system belong to thesecondary circuit of the system?1. Battery, ignition switch, and breaker

points2. Distributor cap, distributor rotor,

and spark plugs3. Battery, spark plugs, and condenser4. Distributor cap, breaker points, and

coil

64-30. The device that serves as a selectorswitch for channeling electricity to theindividual cylinders of a gasoline engineis the1. condenser2. ignition switch3. distributor4. ignitiodcoil

242

A

6-31. In the primary circuit of a gasolineengine ignition bystem, current flowsfrom the ignition coil directly to the1. spark plugs2. distributor rotor3. breaker points4. battery

6-32 The breaker points of a gasoline engineare protected from burning by1.. a condenser2. a coil3. a ground to the engine frame4. ins tors

6-33. A recommended method of cleaning.fouledspark plugs is to1. soak'them in cleaning fluid2. wirebrush or sandblast them3. rub them with an emery cloth4. scrub them with warm soapy water

Learning Objective: Identify themain components of the gas turbineengine and indicate their functions.Textbook pages 167 through 169.

6-34. Gas turbines are like reciprocatingengines in which of the followingrespects?1. Air is compressed2. A fuel-air mixture is burned3. Combustion gases are ended in

developing power4. All of the above respects

6-35. In gas turbine engines compression, com-bustion, and expansion take place inthree separate components while inreciprocating engines these events occurin only one component.

6-36. Which component serves the gas turbineengine as the pistonjerves the recipro-cating engine?1. Burner2. Turbine3. Rotor4. Compressor

6-37. One advantage the gasoline engine hasover the gas turbine is that the gasolineengine /

1. uses less explosive fuel2. consumes fuel at a slower rate3. needs fewer moving parts4. accelerates rapidly from cold starts

a.

6-38. Advantages of the gas turbine engine overthe diesel, engine include all of thefolibwin except1. less bration at full power2. smalle number of components3. faster adjustment to varying loads4. smaller components for air inlet and

exhaust

6-39. Which events occur in the forward sectionof the gas-turbine engine?1. Compression and combustion2. Compression and expansion3. Combustion and expansion4. CombustiOn, compression, and expansion

6-40. Which of the following parts arein the power 9tput section of a gasturbine?1. Compressor2. Burner3. Reduction gear4. Nozzle

6-41. All of the following gas-turbine engineaccessories are driven by the rotorexcept the1. fuel pump2. governor3. oil pump4. overspeed switch

Learning Objective: Recognize safeprocedures in the operation of smallboat engines. Textbook pages 169and 170.

6-42. You are the engineer of a ship's smallboat and the coxswain rings three bells.What does this signal mean?1. Full speed n the direction in which

you are ng2. Ahead ow3. Rever4. Neu al

6-43. After ou start a cold diesel engine,your next step is to run it at1. low speed until it warms up2. ,low speed for a minute so you can

check the supply of lubricating oil3. top speed so you can check the fuel

and cooling systems for leaks4. top speed so you can check the oil

pressure

35

243

4

6-44. If you find that the ex1aust of the dieselengine of a small boat indicates no suc-tion by the water pump during warm-up,you.should1. stop the engine2. pheck,the cooling systeni for clogged

strainers3. check the cooling system for closed

sea valves4. do all the above

6-45. A diesel engine has stopped runningbecause fuel is not'xreaching the enginecylinders. Enciligh fuel remains in the

tank. A possible cause of engine failureis

1. an accummulation of water in thestrainers

2. a plugged vent in the tank filler cap3. a lack of either oil or cooling water4. either 1 or 2 abov)

6-46. When a gasoline-powered boat is beingdriven, which of the following pre-cautions is needed in addition to thosethat apply to a diesel-powered boat?1. Being sure that there is enough

cooling water2. Being sure that the vent in the fuel

tank filler cap is not plugged3. Seeing that the engine compartment is

ventilated so as to pievent an accu-mulation of flammable vapors

4. Seeing that there is an adequatesupply of lubricating oil

6-47. The cause of fuel system failure in adiesel driven boat is often found to

be1. improper cooling

2. water in the strainers

3. an ungrounded fueling hose4. faulty spark plugs

Learning Objective: Recognize theduties and responsibilities ofthe FIREMAN standing engineeringwatches in port and underway.Textbook pages 170 through 176.

6-48. Which assignment is usually carried outby the messenger of the watch during closemaneuvering conditions with other ships?

1. Shaft alley watchstanderI-1- 2. Telephone talker on the engineering

JV circuit3. Evaporator operator4. Throttleman

6-49. What is the maximum time lapse betweenroutine entries in the operating log?1. One half-hour2. One hour3. Four hours4. Twenty-four hours

6-50. If a ship's workday ends at 1600, whenis the most likely time period for stand-ing the sounding and, security watch?1. 1600 to 20002. 1600 to 24003. 1600 to 04004. 1600 to 0800

6-51. A sounding tube is generally constructedof

1. 1/2-inch pipe2. 1 -iech pipr3. 1 1/2-inch pipe4. 2 -inch pipe

^6-52. Why are some sounding tubes constructedso that they terminate in risers extend-ing about three feet above the ship'scompartment to be served?1. They are unable to be extended to

the upper decks2. They are straight3. They have an upper end terminating

in a flush deck plate4. They have a closed threaded plug

6-53. Assume that a sounding tape shows a read-ing of one foo of liquid in a normallydry compartment. What action should betaken?

1. Wait until the next time you takesoundings to see if the level hasincreased

2. Notify the main engineroom so that,the level of liquid can be recorded

3. Pass the word about the liquid levelto your relief

4. 'Notify'your watch supervisorimmediately

6-54. Why should you coat a sounding rod wfihwhite chalk bef e taking a sounding of awater tank?1. To enable the rod to slip through the r

sounding tube without bending2. To make it easier to see the dividing

point between the dry and wet partsof the rod

3. To facilitate leering the rod in thesounding tube

4. To keep the rod from hitting the 1

bottom of the tank with enough forceto damage the rod

2i436

6-55: Assume dint you are on a cold=iron watchand-you find that a welder is weldingin your area without a fire watch. Whataction should you take first?1. Stop the welding2. Report to the OOD3. Station a fire watch4: Bring a fire extinguisher to the area

6-56. When your ship is in drydock, feed watermay not be shifted without permissionfrom the1. officer of the deck2. chief machinist's mate3. engineer officer4. chief boiler technician

6-57. Which of the following jobs will aburnerMan carry out on a shakedown CrUwhile his ship is maneuvering?1. Control forced draft blower2. Warming up standby fuel oil pumps3. Performing routine maintenance4. Cutting burners in and out

6-58-cir

DurIng'regular steaming operations, whichwatchstanders in the fireroom mustcooperate with -each other in marsthat concern the burning of fuel oil?1. :Blowerman and burnerman2. Checkman and burnerman3. Messenger and blowerman4. 'Messenger and checkman

In items 6-59 through 6-63, select from column Bthe fireroom-watchs nder who performs the job 1listed in column Assume that.feed water isbeing controlled ually.

A. Job Watchstantler

6-59. Adjusting the 1.air registers

Mess

2. Burnerman6-60. Maintaining the

proper waterlakrel in the

3. Blowerman

boiler 4. Checkman

6-61. Regulating fueloil pressure atthe burners

6-62. Recording tempera-ture and pressurereadings in theoperating log

C

6-63. Controlling theforced 'draft blowers

ir US GOVERNMENT PRINTING 0I-FICL19/b- 641-277:30

6-64. You can ldarn how a normal reading of athrottleboard differs from an abnnreading.by studying the throttleh dand asking the throttleman questions.

6-65.,4ich watchstander in the engineroom isresponsible for keeping both the standbymain feed pump and standby lube oil pumpready for instant,mse?1. Pumpman2. Upper level watchstander "3. Shaft alley watchstander4. Evaporator watchstander

6-66. Who is responsible for maintainiqg theproper water lever-in a deaerating feedtank located in the engineroom1. Pumpman2. Upper level watchstander3. Checkman4. Evaporator watchstander

6-67. A Fireman Apprentice should learn hisduty stations under various conditions 4of battle readiness by1. checking with his division. officer

frequently2. memorizing the duties of his watch3. followit!g the ordeN of the petty

f the watch4. checking the Watch, Quarter, and

Station,dill frequently

37-

245 a

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