86332162 fluidos spirax sarco design of fluid systems hookup book
DESCRIPTION
Design of Fluid Systems HookUp BookTRANSCRIPT
DESIGNOF FLUID
SYSTEMS
HO
OK
-U
PS
Published by
$19.95 per copy
First Printing January, 1968Second Edition – First Printing October, 1968
Third Edition – First Printing May, 1970Fourth Edition – First Printing September, 1974
Fifth Edition – First Printing August, 1975Sixth Edition – First Printing May, 1978
Seventh Edition – First Printing September, 1981Eighth Edition – First Printing January, 1987Ninth Edition – First Printing April, 1990Tenth Edition – First Printing January, 1991
Eleventh Edition – First Printing April, 1997Twelfth Edition – First Printing June, 2000
Copyright © 2000by Spirax Sarco, Inc.
All Rights ReservedNo part of this publication may be reproduced, stored in a
retrieval system or transmitted, in any form or by any means,electronic, mechanical, photocopying, recording, or otherwise,
without the prior written permission of the publisher.
Spirax Sarco, Inc.1150 Northpoint Blvd. Blythewood, SC 29016
Phone: (803) 714-2000Fax: (803) 714-2200
II
Spirax Sarco
III
Spirax Sarco is the recognized industry standard forknowledge and products and for over 85 years hasbeen committed to servicing the steam users world-wide. The existing and potential applications for steam,water and air are virtually unlimited. Beginning withsteam generation, through distribution and utilizationand ultimately returning condensate to the boiler,Spirax Sarco has the solutions to optimize steam sys-tem performance and increase productivity to savevaluable time and money.
In today’s economy, corporations are looking for reli-able products and services to expedite processes andalleviate workers of problems which may arise withtheir steam systems. As support to industries aroundthe globe, Spirax Sarco offers decades of experience,knowledge, and expert advice to steam users world-wide on the proper control and conditioning of steamsystems.
Spirax Sarco draws upon its worldwide resources ofover 3500 people to bring complete and thorough ser-vice to steam users. This service is built into ourproducts as a performance guarantee. From initial con-sultation to effective solutions, our goal is tomanufacture safe, reliable products that improve pro-ductivity. With a quick, responsive team of salesengineers and a dedicated network of local authorizeddistributors Spirax Sarco provides quality service andsupport with fast, efficient delivery.
Reliable steam system components are at the heart ofSpirax Sarco’s commitment. Controls and regulatorsfor ideal temperature, pressure and flow control; steamtraps for efficient drainage of condensate for maximumheat transfer; flowmeters for precise measurement ofliquids; liquid drain traps for automatic and continuousdrain trap operation to boost system efficiency; rotaryfilters for increased productivity through proper filteringof fluids; condensate recovery pumps for effective con-densate management to save water and sewagecosts; stainless steel specialty products for maintainingquality and purity of steam; and a full range of pipelineauxiliaries, all work together to produce a productivesteam system. Spirax Sarco’s new line of engineeredequipment reduces installation costs with prefabricatedassemblies and fabricated modules for system integri-ty and turnkey advantages.
From large oil refineries and chemical plants to locallaundries, from horticulture to shipping, for hospitals,universities, offices and hotels, in business and gov-ernment, wherever steam, hot water and compressedair is generated and handled effectively and efficiently,Spirax Sarco is there with knowledge and experience.
For assistance with the installation or operation of anySpirax Sarco product or application, call toll free:
1-800-883-4411
How to Use This Book
IV
Selection of the most appropriate type and size ofcontrol valves, steam traps and other fluid controlvalves, steam traps and other fluid control equip-ment, and installation in a hook up enabling thesecomponents of a system to operate in an optimalmanner, all bear directly on the efficiency and econ-omy obtainable in any plant or system.
To help make the best choice, we have assembledinto this book the accumulation of over 85 years ofexperience with energy services in industrial andcommercial use. The hook ups illustrated have allbeen proven in practice, and the reference informa-tion included is that which we use ourselves whenassisting customers choose and use our products.
The Case in Action stories dispersed throughout thisbook are actual applications put to the test by steamusers throughout the country. Their stories are testi-monials to the products and services Spirax Sarcooffers and the benefits they have received from uti-lizing our knowledge and services.
The Hook Up Book is divided into three sections:
Section I is a compilation of engineering data andinformation to assist in estimating loads and flowrates, the basic parameters which enable the bestchoice when selecting sizes.
Section II illustrates how the services and controlequipment can be assembled into hook ups tobest meet the particular needs of each application.
Section III is a summary of the range of SpiraxSarco equipment utilized in the hook ups. Althoughit is not a complete catalog of the entire range, itdoes describe generically the capabilities and limi-tations which must be remembered when makingproper product choices.
Most application problems will be approached in thesame order. Section I will enable the load informa-tion to be collected and the calculations made sothat sizing can be carried out; Section II will makesure that the essentials of the hook up, or combina-tion of hook ups, are not overlooked; and Section IIIwill serve as a guide to the complete equipment cat-alog so that the most suitable equipment can readilybe selected.
The Hook Up Book is intended to serve as a refer-ence for those actively engaged in the design,operation and maintenance of steam, air and liquidsystems. It is also intended as a learning tool toteach engineers how to design productive steamsystems, efficiently and cost effectively.
We gratefully acknowledge the valuable contribu-tions made by our field engineers, representatives,application engineers, and customers to the bodyof accumulated experience contained in this text.
V
Section 1: System Design Information .........................................................1
The Working Pressure in the Boiler and the Mains............................................................2Sizing Steam Lines on Velocity ..........................................................................................3Steam Pipe Sizing for Pressure Drop.................................................................................5Sizing Superheated Mains..................................................................................................6Properties of Saturated Steam ...........................................................................................7Draining Steam Mains ........................................................................................................8Steam Tracing...................................................................................................................12Pressure Reducing Stations .............................................................................................19Parallel and Series Operation of Reducing Valves...........................................................21How to Size Temperature and Pressure Control Valves ..................................................23Temperature Control Valves for Steam Service................................................................26Temperature Control Valves for Liquid Service ................................................................28Makeup Air Heating Coils .................................................................................................31Draining Temperature Controlled Steam Equipment ........................................................33Multi-Coil Heaters .............................................................................................................36Steam Trap Selection .......................................................................................................38Flash Steam......................................................................................................................41Condensate Recovery Systems .......................................................................................45Condensate Pumping .......................................................................................................48Clean Steam .....................................................................................................................50Testing Steam Traps .........................................................................................................55Spira-tec Trap Leak Detector Systems for Checking Steam Traps..................................58Steam Meters....................................................................................................................59Compressed Air Systems .................................................................................................62Reference Charts and Tables ...........................................................................................66
Section 2: Hook-up Application Diagrams................................................83
For Diagram Content, please refer to Diagram Index on page 149.
Section 3: Product Information .....................................................................143
An overview of the Spirax Sarco Product Line
Diagram Index .................................................................................149
Table of Contents
VI
SYSTEMDESIGN
INFORMATION
Section 1
The Working Pressure in the Boiler and the Mains
2
Steam should be generated at apressure as close as possible tothat at which the boiler isdesigned to run, even if this ishigher than is needed in theplant. The reasoning behind thisis clear when consideration isgiven to what happens in thewater and steam space within theboiler. Energy flows into the boil-er water through the outersurface of the tubes, and if thewater is already at saturationtemperature, bubbles of steamare produced. These bubblesthen rise to the surface andbreak, to release steam into thesteam space.
The volume of a given weightof steam contained in the bubblesdepends directly on the pressureat which the boiler is operating. Ifthis pressure is lower than the
design pressure, the volume inthe bubbles is greater. It followsthat as this volume increases, theapparent water level is raised.The volume of the steam spaceabove the water level is therebyreduced. There is increased tur-bulence as the greater volume ofbubbles break the surface, andless room for separation of waterdroplets above the surface.Further, the steam movingtowards the crown or steam take-off valve must move at greatervelocity with a higher volumemoving across a smaller space.All these factors tend to encour-age carryover of water dropletswith the steam.
There is much to be said infavor of carrying the steam closeto the points of use at a high pres-sure, near to that of the boiler.
The use of such pressure meansthat the size of the distributionmains is reduced. The smallermains have smaller heat losses,and better quality steam at thesteam users is likely to result.
Pressure reduction to the val-ues needed by the steam usingequipment can then take placethrough pressure reducing sta-tions close to the steam usersthemselves. The individual reduc-ing valves will be smaller in size,will tend to give tighter control ofreduced pressures, and emit lessnoise. Problems of having awhole plant dependent on a sin-gle reducing station are avoided,and the effects on the steamusers of pressure drops throughthe pipework, which change withvarying loads, disappear.
SYSTEMDESIGN
Table 1: Steam Pipe Sizing for Steam Velocity Capacity of Sch. 80 Pipe in lb/hr steam
Pressure Velocitypsi ft/sec 1/2" 3/4" 1" 11/4" 11/2" 2" 21/2" 3" 4" 5" 6" 8" 10" 12"
50 12 26 45 70 100 190 280 410 760 1250 1770 3100 5000 71005 80 19 45 75 115 170 300 490 710 1250 1800 2700 5200 7600 11000
120 29 60 110 175 245 460 700 1000 1800 2900 4000 7500 12000 1650050 15 35 55 88 130 240 365 550 950 1500 2200 3770 6160 8500
10 80 24 52 95 150 210 380 600 900 1500 2400 3300 5900 9700 13000120 35 72 135 210 330 590 850 1250 2200 3400 4800 9000 14400 2050050 21 47 82 123 185 320 520 740 1340 1980 2900 5300 8000 11500
20 80 32 70 120 190 260 520 810 1100 1900 3100 4500 8400 13200 18300120 50 105 190 300 440 840 1250 1720 3100 4850 6750 13000 19800 2800050 26 56 100 160 230 420 650 950 1650 2600 3650 6500 10500 14500
30 80 42 94 155 250 360 655 950 1460 2700 3900 5600 10700 16500 23500120 62 130 240 370 570 990 1550 2100 3950 6100 8700 16000 25000 3500050 32 75 120 190 260 505 790 1100 1900 3100 4200 8200 12800 18000
40 80 51 110 195 300 445 840 1250 1800 3120 4900 6800 13400 20300 28300120 75 160 290 460 660 1100 1900 2700 4700 7500 111000 19400 30500 4250050 43 95 160 250 360 650 1000 1470 2700 3900 5700 10700 16500 24000
60 80 65 140 250 400 600 1000 1650 2400 4400 6500 9400 17500 27200 38500120 102 240 410 610 950 1660 2600 3800 6500 10300 14700 26400 41000 5800050 53 120 215 315 460 870 1300 1900 3200 5200 7000 13700 21200 29500
80 80 85 190 320 500 730 1300 2100 3000 5000 8400 12200 21000 33800 47500120 130 290 500 750 1100 1900 3000 4200 7800 12000 17500 30600 51600 7170050 63 130 240 360 570 980 1550 2100 4000 6100 8800 16300 26500 35500
100 80 102 240 400 610 950 1660 2550 3700 6400 10200 14600 26000 41000 57300120 150 350 600 900 1370 2400 3700 5000 9100 15000 21600 38000 61500 8630050 74 160 290 440 660 1100 1850 2600 4600 7000 10500 18600 29200 41000
120 80 120 270 450 710 1030 1800 2800 4150 7200 11600 16500 29200 48000 73800120 175 400 680 1060 1520 2850 4300 6500 10700 17500 26000 44300 70200 9770050 90 208 340 550 820 1380 2230 3220 5500 8800 12900 22000 35600 50000
150 80 145 320 570 900 1250 2200 3400 4900 8500 14000 20000 35500 57500 79800120 215 450 850 1280 1890 3400 5300 7500 13400 20600 30000 55500 85500 12000050 110 265 450 680 1020 1780 2800 4120 7100 11500 16300 28500 45300 64000
200 80 180 410 700 1100 1560 2910 4400 6600 11000 18000 26600 46000 72300 100000120 250 600 1100 1630 2400 4350 6800 9400 16900 25900 37000 70600 109000 152000
Sizing Steam Lines On Velocity
3
The appropriate size of pipe tocarry the required amount ofsteam at the local pressure mustbe chosen, since an undersizedpipe means high pressure dropsand velocities, noise and erosion,while a generously sized pipe isunnecessarily expensive to installand heat losses from it will alsobe greater than they need be.
Steam pipes may be sizedeither so that the pressure dropalong them is below an accept-able limit, or so that velocitiesalong them are not too high. It isconvenient and quick to sizeshort mains and branches onvelocity, but longer runs of pipeshould also be checked to seethat pressure drops are not toohigh.
Steam Line VelocitiesIn saturated steam lines, reason-able maximum for velocities areoften taken at 80/120 ft. per sec-ond or 4800/7200 fpm. In thepast, many process plants haveused higher velocities up to 200ft. per second or 12,000 fpm, onthe basis that the increased pipenoise is not a problem within aprocess plant. This ignores theother problems which accompanyhigh velocities, and especially theerosion of the pipework and fit-tings by water droplets moving athigh speed. Only where apprecia-ble superheat is present, with thepipes carrying only a dry gas,should the velocities mentionedbe exceeded. Velocity of saturat-ed steam in any pipe may beobtained from either Table 1, Fig.1 or calculated in ft. per minuteusing the formula:
Formula For Velocity OfSteam In Pipes
V = 2.4Q VsA
Where:V - Velocity in feet per minuteQ - Flow lbs./hr. steamVs - Sp. Vol. in cu. ft./lb. at the
flowing pressureA - Internal area of the pipe—
sq. in.
Steam Piping For PRV’s andFlash VentsVelocity in piping other thansteam distribution lines must becorrectly chosen, including pres-sure reducing valve and flashsteam vent applications.
A look at Steam Properties(Table 3) illustrates how the spe-cific volume of steam increasesas pressure is reduced. To keepreducing valve high and low pres-sure pipe velocity constant, thedownstream piping cross-sec-tional area must be larger by thesame ratio as the change in vol-ume. When downstream pipesize is not increased, low pres-sure steam velocity increasesproportionally. For best PRVoperation, without excessivenoise, long straight pipe runsmust be provided on both sides,with piping reduced to the valvethen expanded downstreamgradually to limit approach andexit steam velocities to 4000/6000 fpm. A sizing example isgiven in Fig. 1.
Line velocity is also importantin discharge piping from steamtraps where two-phase steam/condensate mixtures must beslowed to allow some gravity sep-aration and reduce carryover ofcondensate from flash vent lines.Here line velocities of the flashsteam should not exceed 50/66 ft.per second. A much lower veloci-ty must be provided forseparation inside the flash vesselby expanding its size. The flashload is the total released by hotcondensate from all traps drain-ing into the receiver. Forcondensate line sizing example,see page 46 and see page 43 forvent line sizing example.
SYSTEMDESIGN
Multiply chart velocityby factor below to getvelocity in schedule
80 pipePipe Size Factor
1/2"3/4" & 1"
1-1/4" & 1-1/2"2" to 16"
1.301.231.171.12
20000
12000100008000
600050004000
3000
2000
1000
5000040000
30000
20000
10000
8000
600050004000
3000
2000
1000800
600
100
200
300
400500
Cap
acity
lb/h
ReasonableSteam Velocities
in Pipes
Process Steam8000 to 12000 ft/min
Heating Systems4000 to 6000 ft/min
Vel
ocity
ft/m
in
Steam Pressure psig(Saturated Steam)
Steam Velocity Chart
Pipe Size(Schedule 40 pipe)
25020015012510075
50
25
1050
25020015012510075
50
25
1050
16"
14"12"
10"
8"
6"
4"
3"
2"
1"1-1/4"
5"
3/4"
1/2"
EA
D
G
C
F
B
2-1/2"
1-1/2"
Sizing Steam Lines On Velocity
4
Fig. 1 lists steam capacities ofpipes under various pressure andvelocity conditions.EXAMPLE: Given a steam heat-ing system with a 100 psig inletpressure ahead of the pressurereducing valve and a capacity of1,000 pounds of steam per hourat 25 psig, find the smallest sizesof upstream and downstream pip-ing for reasonable quiet steamvelocities.
Upstream Piping SizingEnter the velocity chart at A for1,000 pounds per hour. Go overto point B where the 100 psigdiagonal line intersects. Followup vertically to C where anintersection with a diagonal linefalls inside the 4,000-6,000foot-per-minute velocity band.Actual velocity at D is about4,800 feet per minute for 1-1/2inch upstream piping.
Downstream Piping SizingEnter the velocity chart at A for1,000 pounds per hour. Go overto point E where the 25 psig diag-onal line intersects. Follow upvertically to F where an intersec-tion with a diagonal line fallsinside the 4,000-6,000 foot-per-minute velocity band. Actualvelocity at G is 5,500 feet perminute for 2-1/2 inch downstreampiping.
Pressure Drop in Steam LinesAlways check that pressure dropis within allowable limits beforeselecting pipe size in long steammains and whenever it is critical.Fig. 2 and Fig. 3 provide drops inSch. 40 and Sch. 80 pipe. Use ofthe charts is illustrated in the twoexamples.
EXAMPLE 1What will be the smallest sched-ule 40 pipe that can be used ifdrop per 100 feet shall notexceed 3 psi when flow rate is10,000 pounds per hour, andsteam pressure is 60 psig?Solution:1. Find factor for steam pres-
sure in main, in this case 60psig. Factor from chart = 1.5.
2. Divide allowable pressuredrop by factor 3 .–. 1.5 = 2 psi.
3. Enter pressure drop chart at2 psi and proceed horizontal-ly to flow rate of 10,000pounds per hour. Select pipesize on or to the right of thispoint. In this case a 4" main.
EXAMPLE 2What will be the pressure dropper 100 feet in an 8" schedule 40steam main when flow is 20,000pounds per hour, and steam pres-sure is 15 psig?
Solution:Enter schedule 40 chart at 20,000pounds per hour, proceed verti-cally upward to 8" pipe curve,then horizontally to pressure dropscale, read 0.23 psi per 100 feet.This would be the drop if thesteam pressure were 100 psig.Since pressure is 15 psig, a cor-rection factor must be used.Correction factor for 15 psig = 3.60.23 x 3.6 = 0.828 psi drop per100 feet for 15 psig
SYSTEMDESIGN
Figure 1: Steam Velocity Chart
Steam Pipe Sizing For Pressure Drop
5
SYSTEMDESIGN
Figure 2: Pressure Drop in Schedule 40 Pipe
Figure 3: Pressure Drop in Schedule 80 Pipe
100 300200 400 500 1,000 2 3 4 5 10,000 2 3 4 5 6 7 8 100,000 2 3 4 5 1,000,000 2.1
.2
.3
.4
.5
.6
.7
.8
.91.0
2.0
3.0
4.05.06.07.08.09.0
10.0
15.03/4" 1" 1-1/4" 1-1/2" 2" 2-1/2" 3" 4" 5" 6" 8" 20"10" 12" 14" 16" 18"
24"
psi 0 2 5 10 15 20 30 40 60 75 90 100 110 125 150 175 200 225 250 300factor 6.9 6.0 5.2 4.3 3.6 3.1 2.4 2.0 1.5 1.3 1.1 1.0 0.92 0.83 0.70 0.62 0.55 0.49 0.45 0.38
350 400 500 6000.33 0.29 0.23 0.19
Steam Flow lbs/hr
100 psig Saturated SteamFor other pressures use correction factors
Pre
ssu
re D
rop
psi
/100
ft
psi 0 2 5 10 15 20 30 40 60 75 90 100 110 125 150 175 200 225 250 300factor 6.9 6.0 5.2 4.3 3.6 3.1 2.4 2.0 1.5 1.3 1.1 1.0 0.92 0.83 0.70 0.62 0.55 0.49 0.45 0.38
350 400 500 6000.33 0.29 0.23 0.19
Steam Flow lbs/hr
100 psig Saturated SteamFor other pressures use correction factors
Pre
ssu
re D
rop
psi
/100
ft
100 300200 400 500 1,000 2 3 4 5 10,000 2 3 4 5 6 7 8100,000 2 3 4 5 1,000,000 2.1
.2
.3
.4
.5
.6
.7
.8
.91.0
2.0
3.0
4.05.06.07.08.09.0
10.0
15.03/4" 1" 1-1/4" 1-1/2" 2" 2-1/2" 3" 4" 5" 6" 8" 20"10" 12" 14" 16" 18" 24"
6
Sizing Superheated Mains
6
Sizing Superheated MainsWhen sizing steam mains forsuperheated service, the follow-ing procedure should be used.Divide the required flow rate bythe factor in Table 2. This will givean equivalent saturated steamflow. Enter Fig. 1, Steam VelocityChart on page 4 to select appro-priate pipe size. If unable, thenuse the formula on page 3 to cal-culate cross sectional area of thepipe and then Tables 38 and 39,page 81, to select the pipe sizewhich closely matches calculatedinternal transverse area.
Example:Size a steam main to carry34,000 lb/h of 300 psig steam at atemperature of 500° F.From Table 2 the correction factoris .96. The equivalent capacity is34,000
.96 = 35,417 lb/h.
Since 300 psig is not found onFig. 1, the pipe size will have tobe calculated. From the formulaon page 3:
V =2.3 x Q x Vs
ASolving for area the formulabecomes:
A =2.4 x Q x Vs
V
Select a velocity of 10,000 ft/min.(which is within the processvelocity range of 8,000 - 12,000ft/min.) and determine Vs (specif-ic volume) of 1.47 ft3/lb (from theSteam Table on page 7). The for-mula is now:
A =2.4 x 35,417 x 1.47
= 12.5 in2
10,000From Tables 38 and 39 (page 81)the pipe closest to this area is 4"schedule 40 or 5" schedule 80.
SYSTEMDESIGN
Table 2: Superheated Steam Correction Factor Gauge Saturated
Pressure Temp. TOTAL STEAM TEMPERATURE IN DEGREES FARENHEITPSI ˚F 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680
15 250 .99 .99 .98 .98 .97 .96 .95 .94 .93 .92 .91 .90 .89 .88 .87 .86 .86 .8520 259 .99 .99 .98 .98 .97 .96 .95 .94 .93 .92 .91 .90 .89 .88 .87 .86 .86 .8540 287 1.00 .99 .99 .98 .97 .96 .95 .94 .93 .92 .91 .90 .89 .88 .87 .86 .86 .8560 308 1.00 .99 .99 .98 .97 .96 .95 .94 .93 .92 .91 .90 .89 .88 .87 .86 .86 .8580 324 1.00 1.00 .99 .99 .98 .97 .96 .94 .93 .92 .91 .90 .89 .88 .87 .86 .86 .85
100 338 – 1.00 1.00 .99 .98 .97 .96 .95 .94 .93 .92 .91 .90 .89 .88 .87 .86 .85120 350 – 1.00 1.00 .99 .98 .97 .96 .95 .94 .93 .92 .91 .90 .89 .88 .87 .86 .85140 361 – – 1.00 1.00 .99 .97 .96 .95 .94 .93 .92 .91 .90 .89 .88 .87 .86 .85160 371 – – – 1.00 .99 .98 .97 .96 .95 .94 .93 .92 .91 .90 .89 .88 .87 .86180 380 – – – 1.00 .99 .98 .97 .96 .95 .94 .93 .92 .91 .90 .89 .88 .87 .86
200 388 – – – 1.00 .99 .99 .97 .96 .95 .94 .93 .92 .91 .90 .89 .88 .87 .86220 395 – – – 1.00 1.00 .99 .98 .96 .95 .94 .93 .92 .91 .90 .89 .88 .87 .86240 403 – – – – 1.00 .99 .98 .97 .95 .94 .93 .92 .91 .90 .89 .88 .87 .86260 409 – – – – 1.00 .99 .98 .97 .96 .94 .93 .92 .91 .90 .89 .88 .87 .86280 416 – – – – 1.00 1.00 .99 .97 .96 .95 .93 .92 .91 .90 .89 .88 .87 .86
300 422 – – – – – 1.00 .99 .98 .96 .95 .93 .92 .91 .90 .89 .88 .87 .86350 436 – – – – – 1.00 1.00 .99 .97 .96 .94 .93 .92 .91 .90 .89 .88 .87400 448 – – – – – – 1.00 .99 .98 .96 .95 .93 .92 .91 .90 .89 .88 .87450 460 – – – – – – – 1.00 .99 .97 .96 .94 .93 .92 .91 .89 .88 .87500 470 – – – – – – – 1.00 .99 .98 .96 .94 .93 .92 .91 .90 .89 .88
550 480 – – – – – – – – 1.00 .99 .97 .95 .94 .92 .91 .90 .89 .88600 489 – – – – – – – – 1.00 .99 .98 .96 .94 .93 .92 .90 .89 .88650 497 – – – – – – – – – 1.00 .99 .97 .95 .94 .92 .91 .90 .89700 506 – – – – – – – – – 1.00 .99 .97 .96 .94 .93 .91 .90 .89750 513 – – – – – – – – – 1.00 1.00 .98 .96 .95 .93 .92 .90 .89
800 520 – – – – – – – – – – 1.00 .99 .97 .95 .94 .92 .91 .90850 527 – – – – – – – – – – 1.00 .99 .98 .96 .94 .93 .92 .90900 533 – – – – – – – – – – 1.00 1.00 .99 .97 .95 .93 .92 .90950 540 – – – – – – – – – – – 1.00 .99 .97 .95 .94 .92 .91
1000 546 – – – – – – – – – – – 1.00 .99 .98 .96 .94 .93 .91
700 720 740 760
.84 .83 .83 .82
.84 .83 .83 .82
.84 .84 .83 .82
.84 .84 .83 .82
.84 .84 .83 .82
.85 .84 .83 .82
.85 .84 .83 .82
.85 .84 .83 .82
.85 .84 .83 .82
.85 .84 .83 .83
.85 .84 .83 .83
.85 .84 .84 .83
.85 .84 .84 .83
.85 .85 .84 .83
.85 .85 .84 .83
.86 .85 .84 .83
.86 .85 .84 .83
.86 .85 .84 .84
.86 .86 .84 .84
.87 .86 .85 .84
.87 .86 .85 .84
.87 .86 .85 .84
.87 .86 .86 .85
.88 .87 .86 .85
.88 .87 .86 .85
.88 .87 .86 .85
.89 .88 .87 .86
.89 .88 .87 .86
.89 .88 .87 .86
.90 .89 .87 .86
Properties Of Saturated Steam
7
SYSTEMDESIGN
Table 3: Properties of Saturated SteamSpecific Specific
Gauge Temper- Heat in Btu/lb. Volume Gauge Temper- Heat in Btu/lb. VolumePressure ature Cu. ft. Pressure ature Cu. ft.
PSIG °F Sensible Latent Total per lb. PSIG °F Sensible Latent Total per lb.
25 134 102 1017 1119 142.0 185 382 355 843 1198 2.2920 162 129 1001 1130 73.9 190 384 358 841 1199 2.2415 179 147 990 1137 51.3 195 386 360 839 1199 2.1910 192 160 982 1142 39.4 200 388 362 837 1199 2.145 203 171 976 1147 31.8 205 390 364 836 1200 2.090 212 180 970 1150 26.8 210 392 366 834 1200 2.051 215 183 968 1151 25.2 215 394 368 832 1200 2.002 219 187 966 1153 23.5 220 396 370 830 1200 1.963 222 190 964 1154 22.3 225 397 372 828 1200 1.924 224 192 962 1154 21.4 230 399 374 827 1201 1.895 227 195 960 1155 20.1 235 401 376 825 1201 1.856 230 198 959 1157 19.4 240 403 378 823 1201 1.817 232 200 957 1157 18.7 245 404 380 822 1202 1.788 233 201 956 1157 18.4 250 406 382 820 1202 1.759 237 205 954 1159 17.1 255 408 383 819 1202 1.72
10 239 207 953 1160 16.5 260 409 385 817 1202 1.6912 244 212 949 1161 15.3 265 411 387 815 1202 1.6614 248 216 947 1163 14.3 270 413 389 814 1203 1.6316 252 220 944 1164 13.4 275 414 391 812 1203 1.6018 256 224 941 1165 12.6 280 416 392 811 1203 1.5720 259 227 939 1166 11.9 285 417 394 809 1203 1.5522 262 230 937 1167 11.3 290 418 395 808 1203 1.5324 265 233 934 1167 10.8 295 420 397 806 1203 1.4926 268 236 933 1169 10.3 300 421 398 805 1203 1.4728 271 239 930 1169 9.85 305 423 400 803 1203 1.4530 274 243 929 1172 9.46 310 425 402 802 1204 1.4332 277 246 927 1173 9.10 315 426 404 800 1204 1.4134 279 248 925 1173 8.75 320 427 405 799 1204 1.3836 282 251 923 1174 8.42 325 429 407 797 1204 1.3638 284 253 922 1175 8.08 330 430 408 796 1204 1.3440 286 256 920 1176 7.82 335 432 410 794 1204 1.3342 289 258 918 1176 7.57 340 433 411 793 1204 1.3144 291 260 917 1177 7.31 345 434 413 791 1204 1.2946 293 262 915 1177 7.14 350 435 414 790 1204 1.2848 295 264 914 1178 6.94 355 437 416 789 1205 1.2650 298 267 912 1179 6.68 360 438 417 788 1205 1.2455 300 271 909 1180 6.27 365 440 419 786 1205 1.2260 307 277 906 1183 5.84 370 441 420 785 1205 1.2065 312 282 901 1183 5.49 375 442 421 784 1205 1.1970 316 286 898 1184 5.18 380 443 422 783 1205 1.1875 320 290 895 1185 4.91 385 445 424 781 1205 1.1680 324 294 891 1185 4.67 390 446 425 780 1205 1.1485 328 298 889 1187 4.44 395 447 427 778 1205 1.1390 331 302 886 1188 4.24 400 448 428 777 1205 1.1295 335 305 883 1188 4.05 450 460 439 766 1205 1.00
100 338 309 880 1189 3.89 500 470 453 751 1204 .89105 341 312 878 1190 3.74 550 479 464 740 1204 .82110 344 316 875 1191 3.59 600 489 473 730 1203 .75115 347 319 873 1192 3.46 650 497 483 719 1202 .69120 350 322 871 1193 3.34 700 505 491 710 1201 .64125 353 325 868 1193 3.23 750 513 504 696 1200 .60130 356 328 866 1194 3.12 800 520 512 686 1198 .56135 358 330 864 1194 3.02 900 534 529 666 1195 .49140 361 333 861 1194 2.92 1000 546 544 647 1191 .44145 363 336 859 1195 2.84 1250 574 580 600 1180 .34150 366 339 857 1196 2.74 1500 597 610 557 1167 .23155 368 341 855 1196 2.68 1750 618 642 509 1151 .22160 371 344 853 1197 2.60 2000 636 672 462 1134 .19165 373 346 851 1197 2.54 2250 654 701 413 1114 .16170 375 248 849 1197 2.47 2500 669 733 358 1091 .13175 377 351 847 1198 2.41 2750 683 764 295 1059 .11180 380 353 845 1198 2.34 3000 696 804 213 1017 .08
IN V
AC
.
Draining Steam Mains
8
Steam main drainage is one of themost common applications forsteam traps. It is important thatwater is removed from steammains as quickly as possible, forreasons of safety and to permitgreater plant efficiency. A build-upof water can lead to waterham-mer, capable of fracturing pipesand fittings. When carried into thesteam spaces of heat exchang-ers, it simply adds to the thicknessof the condensate film andreduces heat transfer. Inadequatedrainage leads to leaking joints,and is a potential cause of wire-drawing of control valve seats.
WaterhammerWaterhammer occurs when a
slug of water, pushed by steampressure along a pipe instead ofdraining away at the low points, issuddenly stopped by impact on avalve or fitting such as a pipebend or tee. The velocities whichsuch slugs of water can achieveare not often appreciated. Theycan be much higher than the nor-mal steam velocity in the pipe,especially when the waterham-mer is occurring at startup.
When these velocities aredestroyed, the kinetic energy in thewater is converted into pressureenergy and a pressure shock isapplied to the obstruction. In mildcases, there is noise and perhapsmovement of the pipe. Moresevere cases lead to fracture of thepipe or fittings with almost explo-sive effect, and consequent escapeof live steam at the fracture.
Waterhammer is avoided com-pletely if steps are taken to ensurethat water is drained away before itaccumulates in sufficient quantity tobe picked up by the steam.
Careful consideration ofsteam main drainage can avoiddamage to the steam main andpossible injury or even loss of life.It offers a better alternative thanan acceptance of waterhammerand an attempt to contain it bychoice of materials, or pressurerating of equipment.
Efficient Steam MainDrainageProper drainage of lines, andsome care in start up methods,not only prevent damage bywaterhammer, but help improvesteam quality, so that equipmentoutput can be maximized andmaintenance of control valvesreduced.
The use of oversized steamtraps giving very generous “safe-ty factors” does not necessarilyensure safe and effective steammain drainage. A number ofpoints must be kept in mind, for asatisfactory installation.1) The heat up method
employed.2) Provision of suitable collect-
ing legs or reservoirs for thecondensate.
3) Provision of a minimum pres-sure differential across thesteam trap.
4) Choice of steam trap typeand size.
5) Proper trap installation.
Heat Up MethodThe choice of steam trap dependson the heat up method adopted tobring the steam main up to fullpressure and temperature. Thetwo most usual methods are:
(a) supervised start up and(b) automatic start up.
A) Supervised Start UpIn this case, at each drain point inthe steam system, a manual drainvalve is fitted, bypassing thesteam trap and discharging toatmosphere.
These drain valves areopened fully before any steam isadmitted to the system. When the“heat up” condensate has beendischarged and as the pressurein the main begins to rise, thevalves are closed. The conden-sate formed under operatingconditions is then dischargedthrough the traps. Clearly, thetraps need only be sized to han-dle the losses from the linesunder operating conditions, givenin Table 5 (page 10).
This heat up procedure ismost often used in large installa-tions where start up of the systemis an infrequent, perhaps even anannual, occurrence. Large heat-ing systems and chemicalprocessing plants are typicalexamples.
SYSTEMDESIGN aaaaaaaaaaaaaaaaaaaaaaa Figure 4
Trap Boiler header or takeoff separatorand size for maximum carryover. On heavy
demand this could be 10% of generating capacity
Separator
Trap Set
SteamSupply
Draining Steam Mains
9
B) Automatic Start UpOne traditional method of achiev-ing automatic start up is simply toallow the steam boiler to be firedand brought up to pressure withthe steam take off valve (crownvalve) wide open. Thus the steammain and branch lines come up topressure and temperature with-out supervision, and the steamtraps are relied on to automatical-ly discharge the condensate as itis formed.
This method is generally con-fined to small installations thatare regularly and frequently shutdown and started up again. Forexample, the boilers in manylaundry and drycleaning plantsare often shut down at night andrestarted the next morning.
In anything but the smallestplants, the flow of steam from theboiler into the cold pipes at startup, while the boiler pressure isstill only a few psi, will lead toexcessive carryover of boilerwater with the steam. Such carry-over can be enough to overloadseparators in the steam takeoff,where these are fitted. Greatcare, and even good fortune, areneeded if waterhammer is to beavoided.
For these reasons, modernpractice calls for an automaticvalve to be fitted in the steamsupply line, arranged so that thevalve stays closed until a reason-able pressure is attained in theboiler. The valve can then bemade to open over a timed periodso that steam is admitted onlyslowly into the distributionpipework. The pressure with theboiler may be climbing at a fastrate, of course, but the slowopening valve protects thepipework.
Where these valves areused, the time available to warmup the pipework will be known, asit is set on the valve control. Inother cases it is necessary toknow the details of the boiler startup procedure so that the time canbe estimated. Boilers started from
cold are often fired for a shorttime and then shut off while tem-peratures equalize. The boilersare protected from undue stressby these short bursts of firing,which extend the warmup timeand reduce the rate at which con-densation in the mains is to bedischarged at the traps.
Determining Condensate LoadsAs previously discussed there aretwo methods for bringing a steammain “on line”. The supervisedstart up bypasses the traps thusavoiding the large warm up loads.The traps are then sized basedon the running conditions found inTable 5 (page 10). A safety factorof 2:1 and a differential pressureof inlet minus condensate returnpressure.
Systems employing automat-ic start up procedures requiresestimation of the amount of con-densate produced in bringing upthe main to working temperatureand pressure within the timeavailable. The amount of conden-sate being formed and thepressure available to discharge itare both varying continually andat any given moment are indeter-minate due to many unknownvariables. Table 4 (page 10) indi-cates the warm up loads per 100
feet of steam main during a onehour start up. If the start up timeis different, the new load can becalculated as follows:
lbs. of Condensate (Table 4) x 60Warm up time in minutes
= Actual warm-up load.
Apply a safety factor of 2:1and size the trap at a differentialpressure of working steam pres-sure minus condensate returnline presure. Since most driptraps see running loads muchmore often than start up loads,care must be taken when sizingthem for start up conditions. If thestart up load forces the selectionof a trap exceeding the capabilityof the “running load trap,” thenthe warm up time needs to beincreased and/or the length ofpipe decreased.
SYSTEMDESIGN
Warm Up Load ExampleConsider a length of 8" main which is to carry steam at 125 psig. Drippoints are to be 150 ft. apart and outside ambient conditions can be aslow as 0°F. Warm-up time is to be 30 minutes.
From Table 4, Warm Up Load is 107 lb./100 ft.For a 150 ft run, load is 107 x 1.5 = 160.5 lb/150 ft.
Correction Factor for 0°F (see Table 4) 1.25 x 160.5 = 200.6 lb/150 ft.A 30 minute warm up time increases the load by
200.6 x 6030
= 401 lb/htotal load
Applying a safety factor of 2:1, the trap sizing load is 802 lb/h. If the backpressure in the condensate return is 0 psig, the trap would be sized fora 125 psi differential pressure. This would result in an oversized trapduring running conditions, calculated at 94 lb/h using Tabe 5 (page 10).Either increase the warm up time to one hour or decrease the distancebetween drip traps.
Draining Steam Mains
10
SYSTEMDESIGN
Table 4: Warm-Up Load in Pounds of Steam per 100 Ft of Steam Main Ambient Temperature 70°F. Based on Sch. 40 pipe to 250 psi, Sch. 80 above 250 except Sch. 120 5" and larger above 800 psi
Steam O°FPressure Main Size Correction
psi 2" 21/2" 3" 4" 5" 6" 8" 10" 12" 14" 16" 18" 20" 24" Factor†0 6•2 9•7 12•8 18•2 24•6 31•9 48 68 90 107 140 176 207 308 1•505 6•9 11•0 14•4 20•4 27•7 35•9 48 77 101 120 157 198 233 324 1•44
10 7•5 11•8 15•5 22•0 29•9 38•8 58 83 109 130 169 213 251 350 1•4120 8•4 13•4 17•5 24•9 33•8 44 66 93 124 146 191 241 284 396 1•3740 9•9 15•8 20•6 90•3 39•7 52 78 110 145 172 225 284 334 465 1•3260 11•0 17•5 22•9 32•6 44 57 86 122 162 192 250 316 372 518 1•2980 12•0 19•0 24•9 35•3 48 62 93 132 175 208 271 342 403 561 1•27
100 12•8 20•3 26•6 37•8 51 67 100 142 188 222 290 366 431 600 1•26125 13•7 21•7 28•4 40 55 71 107 152 200 238 310 391 461 642 1•25150 14•5 23•0 30•0 43 58 75 113 160 212 251 328 414 487 679 1•24175 15•3 24•2 31•7 45 61 79 119 169 224 265 347 437 514 716 1•23200 16•0 25•3 33•1 47 64 83 125 177 234 277 362 456 537 748 1•22250 17•2 27•3 35•8 51 69 89 134 191 252 299 390 492 579 807 1•21300 25•0 38•3 51 75 104 143 217 322 443 531 682 854 1045 1182 1•20400 27•8 43 57 83 116 159 241 358 493 590 759 971 1163 1650 1•18500 30•2 46 62 91 126 173 262 389 535 642 825 1033 1263 1793 1•17600 32•7 50 67 98 136 187 284 421 579 694 893 1118 1367 1939 1•16800 38 58 77 113 203 274 455 670 943 1132 1445 1835 2227 3227 1•156
1000 45 64 86 126 227 305 508 748 1052 1263 1612 2047 2485 3601 1•1471200 52 72 96 140 253 340 566 833 1172 1407 1796 2280 2767 4010 1•1401400 62 79 106 155 280 376 626 922 1297 1558 1988 2524 3064 4440 1•1351600 71 87 117 171 309 415 692 1018 1432 1720 2194 2786 3382 4901 1•1301750 78 94 126 184 333 448 746 1098 1544 1855 2367 3006 3648 5285 1•1281800 80 97 129 189 341 459 764 1125 1584 1902 2427 3082 3741 5420 1•127
†For outdoor temperature of 0°F, multiply load value in table for each main size by correction factor shown.
Table 5: Running Load in Pounds per Hour per 100 Ft of Insulated Steam Main Ambient Temperature 70°F. Insulation 80% efficient. Load due to radiation and convection for saturated steam.
Steam 0°FPressure Main Size Correction
psi 2" 21/2" 3" 4" 5" 6" 8" 10" 12" 14" 16" 18" 20" 24" Factor†10 6 7 9 11 13 16 20 24 29 32 36 39 44 53 1•5830 8 9 11 14 17 20 26 32 38 42 48 51 57 68 1•5060 10 12 14 18 24 27 33 41 49 54 62 67 74 89 1•45
100 12 15 18 22 28 33 41 51 61 67 77 83 93 111 1•41125 13 16 20 24 30 36 45 56 66 73 84 90 101 121 1•39175 16 19 23 26 33 38 53 66 78 86 98 107 119 142 1•38250 18 22 27 34 42 50 62 77 92 101 116 126 140 168 1•36300 20 25 30 37 46 54 68 85 101 111 126 138 154 184 1•35400 23 28 34 43 53 63 80 99 118 130 148 162 180 216 1•33500 27 33 39 49 61 73 91 114 135 148 170 185 206 246 1•32600 30 37 44 55 68 82 103 128 152 167 191 208 232 277 1•31800 36 44 53 69 85 101 131 164 194 214 244 274 305 365 1•30
1000 43 52 63 82 101 120 156 195 231 254 290 326 363 435 1•271200 51 62 75 97 119 142 185 230 274 301 343 386 430 515 1•261400 60 73 89 114 141 168 219 273 324 356 407 457 509 610 1•251600 69 85 103 132 163 195 253 315 375 412 470 528 588 704 1•221750 76 93 113 145 179 213 278 346 411 452 516 580 645 773 1•221800 79 96 117 150 185 221 288 358 425 467 534 600 667 800 1•21
†For outdoor temperature of 0°F, multiply load value in table for each main size by correction factor shown.
Draining Steam Mains
11
Draining Steam MainsNote from the example that inmost cases, other than large dis-tribution mains, 1/2" Thermo-Dynamic® traps have amplecapacity. For shorter lengthsbetween drip points, and for smalldiameter pipes, the 1/2" lowcapacity TD trap more than meetseven start up loads, but on largermains it may be worth fitting par-allel 1/2" traps as in Fig. II-6 (page86). Low pressure mains are bestdrained using float and thermo-static traps, and these traps canalso be used at higher pressures.
The design of drip stationsare fairly simple. The most com-mon rules to follow for sizing thedrip pockets are:1. The diameter of the drip pock-
ets shall be the same size asthe distribution line up to 6inches in diameter. The diam-eter shall be half the size of thedistribution line over 6 inchesbut never less than 6 inches.
2. The length of the drip pocketshall be 1-1/2 times the diam-eter of the distribution line butnot less than 18 inches.
Drip Leg SpacingThe spacing between thedrainage points is often greaterthan is desirable. On a long hori-zontal run (or rather one with afall in the direction of the flow ofabout 1/2" in 10 feet or 1/250)drain points should be provided atintervals of 100 to 200 feet.Longer lengths should be split upby additional drain points. Anynatural collecting points in thesystems, such as at the foot ofany riser, should also be drained.
A very long run laid with a fallin this way may become so lowthat at intervals it must be elevat-ed with a riser. The foot of each ofthese “relay points” also requires acollecting pocket and steam trap.
Sometimes the ground con-tours are such that the steammain can only be run uphill. Thiswill mean the drain points shouldbe at closer intervals, say 50 ft.apart, and the size of the mainincreased. The lower steamvelocity then allows the conden-sate to drain in the oppositedirection to the steam flow.
Air venting of steam mains isof paramount importance and isfar too often overlooked. Steamentering the pipes tends to pushthe air already there in front of itas would a piston. Automatic airvents, fitted on top of tees at theterminal points of the main andthe larger branches, will allow dis-charge of this air. Absence of airvents means that the air will passthrough the steam traps (where itmay well slow down the dis-charge of condensate) or throughthe steam using equipment itself.
SYSTEMDESIGN
Figure 5Draining and Relaying Steam Main
Fall 1/2" in 10 FtSteam
Steam Trap
Steam Trap
Steam TrapSteam TrapSteam Trap
Condensate
The majority of steam traps in refineries are installed onsteam main and steam tracing systems. Thoroughdrainage of steam mains/branch lines is essential for effec-tive heat transfer around the refinery and for waterhammerprevention. This holds true for condensate drainage fromsteam tracing lines/jackets, though some degree of back-up (or sub-cooling) is permissible in some applications.
The predominant steam trap installed is a non-repairable type that incorporates a permanent pipelineconnector. Scattered throughout the system are a numberof iron and steel body repairable types.
Most notable failure of steam traps are precipitate for-mation on bucket weep-holes and discharge orifices thateventually plugs the trap shut. A common culprit is valvesealing compound injected into leaking valves which formssmall pellets that settle in low points, such as driplegs/steam traps and on strainer screens making blowdown difficult. This problem also occurs during occasional“system upset” when hydrocarbon contaminants are mis-takenly introduced to the steam system.
A noise detector and/or a temperature-indicatingdevice is required to detect trap failure. Especially costly is
the fact that operators are not allowed to remove traps forrepair when threading from the line is required.Maintenance personnel must be involved.
SolutionUniversal connector steam traps were installed for trial inone of the dirtiest drip stations at the refinery. The trapsheld up under adverse operating conditions requiring onlyperiodic cleaning. Since the time of installation, all failedinverted bucket traps in this service were replaced withuniversal connector traps. Strainers were installedupstream of each.
Benefits• The addition of Thermo-Dynamic® traps allowed for eas-
ier field trap testing.• The addition of universal connectors significantly
reduced steam trap installation and repair time.• 33% reduction in steam trap inventory due to standard
trap for all sizes.• Reduced energy loss is significantly reduced using Thermo-
Dynamic® steam traps versus original inverted bucket traps.
Case in Action: Steam Main and Steam Tracing System Drainage
Steam Tracing
12
The temperature of process liquidsbeing transferred through pipelinesoften must be maintained to meetthe requirements of a process, toprevent thickening and solidifica-tion, or simply to protect againstfreezeup. This is achieved by theuse of jacketed pipes, or by attach-ing to the product line one or moreseparate tracer lines carrying aheating medium such as steam orhot water.
The steam usage may be rel-atively small but the tracingsystem is often a major part of thesteam installation, and the sourceof many problems.
Many large users and plantcontractors have their owninhouse rules for tracer lines, butthe following guidelines may beuseful in other cases. We havedealt only with external tracing,this being the area likely to causedifficulties where no existingexperience is available. Externaltracing is simple and thereforecheap to install, and fulfills theneeds of most processes.
External Tracer LinesOne or more heat carrying lines, ofsizes usually from 3/8" up to 1"nominal bore are attached to themain product pipe as in Fig. 6.Transfer of heat to the product linemay be three ways—by conductionthrough direct contact, by convec-tion currents in the air pocketformed inside the insulating jacket,and by radiation. The tracer linesmay be of carbon steel or copper,or sometimes stainless steel.
Where the product line is of aparticular material to suit the fluidit is carrying, the material for thetracer line must be chosen toavoid electrolytic corrosion at anycontact points.
For short runs of tracer, suchas around short vertical pipes, orvalves and fittings, small bore cop-per pipes, perhaps 1/4" bore maybe wound around the product linesas at Fig. 7. The layout should bearranged to give a continuous fallalong the tracers as Fig. 9a rather
than Fig. 9b, and the use of wraparound tracers should be avoidedon long horizontal lines.
A run of even 100 ft. of 6 inchproduct line will have a total ofabout 500 to 600 ft. of wraparound tracer. The pressure dropalong the tracer would be veryhigh and the temperature at theend remote from the supply wouldbe very low. Indeed, this end ofthe tracer would probably containonly condensate and the temper-ature of this water would fall as itgives up heat. Where steam ispresent in the tracer, lifting thecondensate from the multiplicity oflow points increases the problemsassociated with this arrangement.
SYSTEMDESIGN
Figure 6Tracer Attached To Product Line
LaggingProduct
AluminumFoil
Air Space
Tracer
Figure 7Small Bore TracingWraped AroundVertical Product Line
Figure 8Clipping Tracer Around Bends
Figure 9 Continuous Fall On Wrap Around Tracer
Figure 10 Attaching Tracer To Line
Figure 10a Short Run Welds
Figure 10b Continuous Weld
Figure 10c Heat Conducting Paste
Product
Lagging
Tracer
HeatConducting
Paste
9a 9b
Steam Tracing
13
Clip On TracersThe simplest form of tracer is onethat is clipped or wired on to themain product line. Maximum heatflow is achieved when the traceris in tight contact with the productline. The securing clips should beno further apart than 12" to 18" on3/8" tracers, 18" to 24 on 1/2",and 24" to 36" on 3/4" and larger.
The tracer pipes can be liter-ally wired on, but to maintainclose contact it is better to useeither galvanized or stainlesssteel bands, about 1/2" wide and18 to 20 gauge thickness. Onevery practical method is to use apacking case banding machine.Where tracers are carried aroundbends particular care should betaken to ensure that good contactis maintained by using three ormore bands as in Fig. 8.
Where it is not possible to usebands as at valve bodies, softannealed stainless steel wire 18gauge thick is a useful alternative.Once again, any special needs toavoid external corrosion or elec-trolytic action may lead to thesesuggestions being varied.
Welded TracersWhere the temperature differ-ence between the tracer and theproduct is low, the tracer may bewelded to the product line. Thiscan be done either by short runwelds as Fig. 10a or by a contin-uous weld as Fig. 10b formaximum heat transfer.
In these cases the tracer issometimes laid along the top ofthe pipe rather than at the bot-tom, which greatly simplifies thewelding procedure. Advocates ofthis method claim that this loca-tion does not adversely affect theheat transfer rates.
Heat Conducting PasteFor maximum heat transfer, it canbe an advantage to use a heatconducting paste to fill the normalhot air gap as in Fig. 10c. Thepaste can be used to improveheat transfer with any of the clip-ping methods described, but it isessential that the surfaces arewirebrushed clean before apply-ing the paste.
Spacer TracingThe product being carried in theline can be sensitive to tempera-ture in some cases and it is thenimportant to avoid any local hotspots on the pipe such as couldoccur with direct contact betweenthe tracer and the line.
This is done by introducing astrip of insulating materialbetween the tracer and the prod-uct pipe such as fiberglass,mineral wool, or packing blocks ofan inert material.
InsulationThe insulation must cover boththe product line and the tracer butit is important that the air spaceremains clear. This can beachieved in more than one way.1. The product line and tracer
can first be wrapped with alu-minum foil, or by galvanizedsteel sheet, held on by wiringand the insulation is thenapplied outside this sheet.Alternatively, small mesh gal-vanized wire netting can beused in the same way asmetal sheet Fig. 11a.
2. Sectional insulation, pre-formed to one or two sizeslarger than the product main,can be used. This has thedisadvantage that it can eas-ily be crushed Fig. 11b.
3. Preformed sectional insula-tion designed to cover bothproduct line and tracer canbe used, as Fig. 11c.Preformed sectional insula-
tion is usually preferred to plasticmaterial, because being rigid itretains better thickness and effi-ciency. In all cases, the insulationshould be properly finished withwaterproof covering. Most insula-tion is porous and becomesuseless as heat conserving mate-rial if it is allowed to absorb water.Adequate steps may also beneeded to protect the insulationfrom mechanical damage.
SYSTEMDESIGN
Figure 11Insulating Tracer and Product Lines
ProductLagging
TracerAluminum
Foil
Wire Netting
ProductLagging
Tracer
Product
Lagging
Tracer
11b 11c11a
Steam Tracing
14
Sizing of External TracersThe tracing or jacketing of any linenormally aims at maintaining thecontents of the line at a satisfac-tory working temperature underall conditions of low ambient tem-perature with adequate reserve tomeet extreme conditions.
Remember that on someexposed sites, with an ambientstill air temperature of say 0°F,the effect of a 15 mph wind will beto lower the temperature to anequivalent of -36°F.
Even 32°F in still air can belowered to an effective 4°F with a20 mph wind—circumstanceswhich must be taken into full con-sideration when studying thetracer line requirements.
Details of prevailing condi-tions can usually be obtainedfrom the local meteorologicaloffice or civil air authority.
Most of the sizing of externaltracers is done by rule of thumb,but the problem which arises hereis what rule and whose thumb?
Rules of thumb are generallybased on the experiences of a cer-tain company on a particularprocess and do not necessarilyapply elsewhere. There are alsowidely differing opinions on the lay-out: some say that multiple tracersshould all be below the center lineof the product line while others say,
with equal conviction, that it is per-fectly satisfactory to space thetracers equally around the line.
Then there are those who willendeavor to size their tracers from3/8", 1/2", 3/4" or 1" and evenlarger pipe: while another schoolof thought says that as tracershave only minute contact with theproduct line it will give much moreeven distribution of heat if all trac-ers are from 1/2" pipe in multiplesto meet the requirements. Thisdoes have the added advantageof needing to hold a stock of onlyone size of pipe and fittings ratherthan a variety of sizes.
For those who like to followthis idea, Table 6 will be useful formost average requirements.
Type A would suffice for mostfuel oil requirements and wouldalso meet the requirement ofthose lines carrying acid, phenol,water and some other chemicals,but in some cases spacersbetween the product line andsteam line would be employed.
The steam pressure is impor-tant and must be chosenaccording to the product temper-ature required.
For noncritical tracing TypesA & B (Table 6) a steam pressureof 50 psi would generally be suit-able. For Type C, a higherpressure and a trap with a hotdischarge may be required.
Jacketed LinesIdeally jacketed lines should beconstructed in no more than 20 ft.lengths and the condensateremoved from each section.Steam should enter at the highestend so that there is a natural fall tothe condensate outlet as Fig. 12a.
When it is consideredimpractical to trap each length, anumber of lengths up a total of80-100 ft. approx. may be joinedtogether in moderate climates,but in extremely cold parts of theworld 40 ft. should be the maxi-mum. See Fig. 12b.
Always avoid connectingsolely through the bottom loop.This can only handle the conden-sate and impedes the free flow ofsteam as Fig. 12c. As a generalguide, see Table 7.
Although in most cases 1/2"condensate outlet will be ade-quate, it is usual to make this thesame size as the steam connec-tion as it simplifies installation.
External TracersIn horizontal runs, the steam willgenerally flow parallel to the prod-uct line, but as far as possible,steam should enter from the highend to allow free flow of the con-densate to the low end, i.e. itshould always be self-draining.
It is generally consideredpreferable to fit one tracer on thebottom of the line as Fig. 13a, twotracers at 30° as Fig. 13b, threetracers at 45° as Fig. 13c.
Where multiple 1/2" tracersare used, they should be arrangedin loop fashion on either side ofthe product line, as Fig. 14. In ver-tical lines, the tracers would bespaced uniformly, as Fig. 15a & b.
The maximum permissiblelength of tracer will depend to someextent on the size and initial steampressure, but as a general guide3/8” tracers should not exceed 60ft. in length and the limit for all othersizes should be about 150 ft.
Bends and low points in thetracer, as Fig. 16a should alwaysbe avoided. For example, if it isnecessary to carry a tracer lineround a pipe support or flange,
SYSTEMDESIGN
Table 6: Number of 1/2" (15mm) Tracers Usedwith Different Sizes of Product Lines
Type A Type B Type CNoncritical Noncritical Critical
General frost protection or Where solidification may When solidification maywhere solidification may occur at temps between occur at temps between
occur at temps below 75°F 75-150°F 150-300°F
Product Number of 1/2" Number of 1/2" Number of 1/2"Line Size Tracers Tracers Tracers1" 1 1 111/2" 1 1 22" 1 1 23" 1 1 34" 1 2 36" 2 2 38" 2 2 310"-12" 2 3 614"-16" 2 3 818"-20" 2 3 10
Steam Tracing
15
this should be done in the hori-zontal plane, Fig. 16b.
Where it is essential to main-tain the flow of heat to theproduct, the tracer should betaken up to the back of the flangeFig. 17, and the coupling shouldalways be on the center line ofthe flanged joint.
The same applies to an in-line run where the tracer has tobe jointed. This can be done intwo ways, Fig. 18 or Fig. 19.
Each of these is preferable toFig. 20 which could produce acold spot. Where two tracers areused it can be better to doubleback at a union or flange as Fig.21, rather than jump over it.
ExpansionExpansion in tracer lines is oftenoverlooked. Naturally the steamheated tracer will tend to expandmore than the product line.Where the tracer has to passaround flanges, the bends arequite adequate to take care of theexpansion, Fig. 22.
But where this does not occurand there is a long run of uninter-rupted tracer, it is essential toprovide for expansion which canbe done by forming a completeloop, Fig. 23.
SYSTEMDESIGN
Table 7: Steam Connection Size for Jacketed Lines Product Jacket Steam
Line Diameter Connection2-1/2" 65mm 4" 100mm 1/2" 15mm
3" 80mm 6" 150mm 3/4" 20mm4" 100mm 6" 150mm 3/4" 20mm6" 150mm 8" 200mm 3/4" 20mm8" 200mm 10" 250mm 1" 25mm10" 250mm 12" 300mm 1" 25mm
Figure 13Single and Multiple Tracing
Figure 12aJacketed Lines, Drained Separately
Figure 12bJacketed Lines, Connected
Figure 12cIncorrect Arrangement of Jacketed Lines
13a 13b 13c
Figure 14Multiple Tracing
Figure 15 Vertical Tracing
15a 15b
Figure 16a Incorrect Arrangement
Figure 16b Correct Arrangement
Figure 17
Figure 18
Figure 22Correct Arrangement
Figure 19 for Tracer-line Joints
Figure 20 Incorrect Arrangement
Figure 21Dual Tracer Double Back
Figure 23Expansion Arrangementson Long Tracers
Steam
SteamFall
Fall
Steam TrapSteam Trap
SteamTrap
Steam Trap
Steam
General Installation
Steam Tracing
16
Tracer Steam DistributionIt is important that the steam sup-ply should always be taken froma source which is continuouslyavailable, even during a normalshut down period.
Tracer lines and jacketed pipemay have to work at any steampressure (usually in the rangebetween 10 and 250 psi, butalways choose the lowest pres-sure to give the required producttemperature. Excessively highpressures cause much waste andshould only be used where a highproduct temperature is essential).
To suit product temperaturerequirements, it may be necessaryto use steam at different pres-sures. It should be distributed atthe highest pressure and reduceddown to meet the lower pressurerequirements. A Reducing Valvecan be used for this purpose, Fig.24. Note: it may be necessary tosteam trace the valve body to pre-vent damage due to freezing..
A number of tracers can besupplied from one local distribu-tion header. This header shouldbe adequately sized to meet themaximum load and drained at itslow point by a steam trap as Fig.25. All branches should be takenoff the top of this header, onebranch to each tracer line. Thesebranches should be fitted withisolating valves.
Don’t undersize these branchconnections (1/2" supply to even a3/8" tracer will avoid undue pres-sure drop) and serve only tracers
local to the header, otherwise highpressure drop may result.
The size of the header will, ofcourse, depend upon the steampressure and the total load on thetracers but as a general guide,see Table 8:
Tracer Trap SizingSubcooled discharge traps areusually a good choice for tracerservice. Tracing loads areapproximately 10 to 50 lb./hr., andeach tracer requires its own lowcapacity trap.
No two tracers can haveexactly the same duty, so grouptrapping two or more tracers toone trap can considerably impairthe efficiency of heat transfer, seeFig. 26 and Fig. 27.
Even with multiple tracers ona single product line, each tracer
should be separately trapped—Fig. 28.
When branched tracers aretaken to serve valves, then eachshould be separately trapped,Figs. 29, 30, 31 and 32.
SYSTEMDESIGN
Table 8 Recommended header size
for supplying steam tracer lines
Header Size Number of 1/2" Tracers3/4" 21" 3-5
11/2" 6-152" 16-30
Recommended header sizefor condensate lines
Header Size Number of 1/2" Tracers1" Up to 5
11/2" 6-102" 11-25 Figure 28
Header Steam Trap
Tracers
Figure 27Correct Arrangement
Figure 26Incorrect Arrangement
Figure 25
Steam Trap
Steam Trap
Steam Trap
Steam Trap
Steam TrapSteamTrap
Steam Trap
Steam Trap
Steam
Steam
Steam
3/8" (10mm) OD1/4" (6mm) Bore
3/8" (10mm) OD, 1/4" (6mm) Bore
Figure 31Tracer Lines Around Pump Casing
Figure 29
Figure 30
Figure 24Spirax SarcoReducingValve
Steam
Steam
Steam
Steam Tracing
17
Important—Getting Rid of the MuckPipes delivered to the site maycontain mill scale, paint, preserv-ing oils, etc. and during storageand erection will collect dirt, sand,weld splatter and other debris, sothat on completion, the averagetracer line contains a consider-able amount of “muck.”
Hydraulic testing will convertthis “muck” into a mobile sludgewhich is not adequately washedout by simply draining down aftertesting.
It is most important that thelines are properly cleaned byblowing through with steam to anopen end before diverting to thesteam traps.
Unless this is done, the trapswill almost certainly fail to operatecorrectly and more time will bespent cleaning them out when theplant is commissioned.
Steam Traps For Tracer LinesAlmost any type of steam trapcould be used to drain tracerlines, but some lend themselvesto this application better than oth-ers. The traps should bephysically small and light inweight, and as they are often fit-ted in exposed positions, theyshould be resistant to frost. Thetemperature at which the conden-sate is discharged by the trap isperhaps the most important con-sideration when selecting thetype of trap.
Thermo-Dynamic® traps arethe simplest and most robust ofall traps, they meet all of theabove criteria and they dischargecondensate at a temperatureclose to that of steam. Thus theyare especially suitable on thosetracing applications where theholding back of condensate in thetracer line until it has subcooledwould be unacceptable. Tracersor jackets on lines carrying sul-phur or asphalt typify theseapplications where the tracermust be at steam temperaturealong its whole length.
It must be remembered thatevery time a Thermo-Dynamic®
trap opens, it discharges conden-sate at the maximum ratecorresponding to the differentialpressure applied. The instanta-neous release rates of the steamflashing off the condensate canbe appreciable, and care is need-ed to ensure that condensatereturn lines are adequately sized
if high back pressures are to beavoided. Thus, the use of sweptback or “y” connections from trapdischarges into common headersof generous size will help avoidproblems.
Where the traps are exposedto wind, rain or snow, or lowambient temperatures, the steambubbles in the top cap of the trapcan condense more quickly, lead-ing to more rapid wear. Specialinsulating caps are available forfitting to the top caps to avoidthis, Fig. 33.
In other non-critical applica-tions, it can be convenient andenergy efficient to allow the con-densate to sub-cool within thetracer before being discharged.This enables use to be made ofsome of the sensible heat in thecondensate, and reduces or eveneliminates the release of flashsteam. Temperature sensitivetraps are then selected, usingeither balanced pressure orbimetallic elements.
The bimetallic traps usuallydischarge condensate at somefairly constant differential such as50°F below condensing tempera-tures, and tend to give acontinuous dribble of condensatewhen handling tracer loads, help-ing minimize the size ofcondensate line needed. Theyare available either in maintain-able versions, with a replaceableelement set which includes thevalve and seat as well as thebimetallic stack, or as sealednon-maintainable units asrequired.
Balanced pressure traps nor-mally operate just below steamtemperature, for critical tracingapplications, see Fig. 34.
The trap is especially suitablewhere small quantities ofcondensate are produced, onapplications where sub-cooling isdesirable, and where the conden-sate is not to be returned to therecovery system.
SYSTEMDESIGN
Figure 32Typical Instrument Tracing
Steam Trap
Steam
3/8" (10mm) OD1/4" (6mm) Bore
1/2" (15mm) OD
Figure 34Balanced Pressure Tracer Trap
Figure 33Insulating Cap forThermo-Dynamic®
Trap
Steam Tracing
18
A similar but maintainabletype intended for use on instru-ment tracer lines, where thephysical size of the trap is impor-tant as well as its operatingcharacteristics is shown in Fig. 35.
Just as the distribution ofsteam is from a common header,it often is convenient to connect anumber of traps to a commoncondensate header and this sim-plifies maintenance. As noted, thedischarge should preferably enterthe header through swept con-nections and the headers beadequately sized as suggested inTable 8 (page 16).
SYSTEMDESIGN
During steam tracing project design, it was found that fivethousand feet of 2" product piping was to be traced with150 psig steam. Product temperature was to be main-tained at 100°F, with maximum allowable temperature of150°F and a minimum allowable temperature of 50°F.
Of particular concern was the fact that the pipelinewould always be full of the product, but flow would beintermittent. Overheating could be a real problem. In addi-tion, the tracing system had to be protected from freezing.
SolutionThe 5,000 feet of product piping was divided into 30 sep-arate traced sections including: a cast steel temperatureregulator, a bronze temperature control valve used as ahigh limit safety cutout, a sealed balanced pressure ther-mostatic steam trap, a vacuum breaker, and pressureregulators supplying steam to all 30 tracing sections. Eachsection operates effectively at the desired temperature,regardless of flow rate or ambient temperature.
Benefits• The chance of product damage from overheating is min-
imized and steam consumption is reduced throughsteam pressure reduction (150 psig to 50 psig) with thepressure regulator.
• The product temperature is maintained at a consistentset temperature, maximizing process control under allflow conditions with the temperature regulator.
• Product damage from overheating is prevented throughuse of the high limit safety cutout. The system will shutdown completely, should the temperature regulator over-shoot its set point.
• The tracing system is protected from freezing with thesealed balanced pressure thermostatic steam trap dis-charging to drain. Thorough drainage is also facilitatedby the vacuum breaker.
Case in Action: Product Steam Tracing with Temperature Control and Overheat Protection
These may be increasedwhere high pressures and trapsdischarging condensate at nearsteam temperature are used, ordecreased with low pressuresand traps discharging cooler con-densate.
Temperature Controlof TracerWhere it is essential to preventoverheating of the product, orwhere constant viscosity isrequired for instrumentation,automatic temperature control isfrequently used.
On many systems, the sim-plest way to achieve control is touse a reducing valve on thesteam supply to the tracer lines orjacket. This can be adjusted inthe light of experience to give thecorrect steam pressure to pro-duce the required producttemperature.
Clearly this is an approximateway to control product tempera-ture and can only be used wherethe product flow is fairly constant.Where closer control is required,
Figure 35Maintainable Balanced PressureTracer Trap.
the simple direct acting tempera-ture control often provides aneconomic solution. This will giveclose control and since it is notnecessary to provide either elec-tric power or compressed air, thefirst cost and indeed the runningcosts are low.
Pressure Reducing Stations
19
Pressure Reducing StationsIt is a mistake to install even thebest of pressure reducing valvesin a pipeline without giving somethought to how best it can behelped to give optimal perfor-mance.
The valve selected should beof such a size that it can handlethe necessary load, but oversiz-ing should be avoided. Theweight of steam to be handled ina given time must be calculatedor estimated, and a valve capableof passing this weight from thegiven upstream pressure to therequired downstream pressure ischosen. The valve size is usuallysmaller than the steam pipeseither upstream or downstream,because of the high velocitieswhich accompany the pressuredrop within the valve.
Types of Pressure ReducingValves are also important andcan be divided into three groupsof operation as follows:
Direct Operated ValvesThe direct acting valve shown inFig. II-17 (page 91) is the sim-plest design of reducing valve.
This type of valve has twodrawbacks in that it allowsgreater fluctuation of the down-stream pressure under unstableload demands, and these valveshave relatively low capacity fortheir size. It is nevertheless per-fectly adequate for a whole rangeof simple applications whereaccurate control is not essentialand where the steam flow is fairlysmall and constant.
Pilot Operated ValvesWhere accurate control of pres-sure or large capacity is required,a pilot operated reducing valveshould be used. Such a valve isshown in Fig. II-12 (page 89).
The pilot operated designoffers a number of advantagesover the direct acting valve. Only avery small amount of steam has toflow through the pilot valve to pres-surize the main diaphragm
chamber and fully open the mainvalve. Thus, only very smallchanges in downstream pressureare necessary to produce largechanges in flow. The “droop” of pilotoperated valves is therefore small.Although any rise in upstreampressure will apply an increasedclosing force on the main valve, thisis offset by the force of theupstream pressure acting on themain diaphragm. The result is avalve which gives close control ofdownstream pressure regardlessof variations on the upstream side.
Pneumatically OperatedValvesPneumatically operated controlvalves, Fig. II-20 (page 93), withactuators and positioners beingpiloted by controllers, will providepressure reduction with evenmore accurate control.
Controllers sense down-stream pressure fluctuations,interpolate the signals and regu-late an air supply signal to apneumatic positioner which in turnsupplies air to a disphragm open-ing a valve. Springs are utilized asan opposing force causing thevalves to close upon a loss orreduction of air pressure appliedon the diaphragm. Industrysophistication and control needsare demanding closer and moreaccurate control of steam pres-sures, making pneumatic controlvalves much more popular today.
Piping And NoiseConsiderationThe piping around a steam pres-sure reducing valve must beproperly sized and fitted for bestoperation. Noise level of a reduc-ing station is lowest when thevalve is installed as follows:1. Avoid abrupt changes in
direction of flow. Use longradius bends and “Y” pipinginstead of “T” connections.
2. Limit approach and exitsteam velocity to 4000 to6000 FPM.
3. Change piping graduallybefore and after the valve withtapered expanders, or changepipe only 1 or 2 sizes at a time.
4. Provide long, straight, full-sizeruns of heavy wall pipe onboth sides of the valve, andbetween two-stage reductionsto stabilize the flow.
5. Use low pressure turndownratios (non-critical.)
6. Install vibration absorbingpipe hangers and acousticalinsulation.Most noise is generated by a
reducing valve that operates atcritical pressure drop, especiallywith high flow requirements.Fitting a noise diffuser directly tothe valve outlet will reduce thenoise level by approx. 15 dBA.
It must also be rememberedthat a valve designed to operate onsteam should not be expected towork at its best when supplied witha mixture of steam, water and dirt.
A separator, drained with asteam trap, will remove almost allthe water from the steam enteringthe pressure reducing set. Thebaffle type separator illustrated inFig. 36 has been found to be veryeffective over a broad range offlows.
SYSTEMDESIGN
Figure 36Moisture Separator for Steam or Air
Pressure Reducing Stations
20
PRV Station ComponentsA stop valve is usually needed sothat the steam supply can be shutoff when necessary, and thisshould be followed by a line sizestrainer. A fine mesh stainlesssteel screen in the strainer willcatch the finer particles of dirtwhich pass freely through stan-dard strainers. The strainer shouldbe installed in the pipe on its side,rather than in the conventionalway with the screen hangingbelow the pipe. This is to avoid thescreen space acting as a collect-ing pocket for condensate, sincewhen installed horizontally thestrainer can be self-draining
Remember that water whichcollects in the conventionally pipedstrainer at times when the reducingvalve has closed, will be carriedinto the valve when it begins toopen. This water, when forcedbetween the valve disc and seat ofthe just-opening valve, can leadrapidly to wire-drawing, and theneed for expensive replacements.
Pressure gauges at each sideof the reducing valve allow its per-formance to be monitored. At thereduced pressure side of the valve,a relief or safety valve may berequired. If all the equipment con-nected on the low pressure side iscapable of safely withstanding theupstream pressure in the event ofreducing valve failure, the reliefvalve may not be needed. It maybe called for if it is sought to protectmaterial in process from overlyhigh temperatures, and it is essen-tial if any downstream equipmentis designed for a pressure lowerthan the supply pressure.
Steam Safety Valve SizingWhen selecting a safety valve, thepressure at which it is to openmust be decided. Opening pres-sure must be below the limitationsof the downstream equipment yetfar enough above the normalreduced pressure that minor fluc-tuations do not cause opening ordribbling. Type “UV” Safety Valvesfor unfired pressure vessels aretested to ASME Pressure VesselCode, Section VIII and achieverated capacity at an accumulatedpressure 10% above the set-to-
open pressure. Safety valves foruse on boilers carry a “V” stampand achieve rated capacity at only3% overpressure as required bySection I of the Code.
The capacity of the safetyvalve must then equal or exceed
SYSTEMDESIGN
Figure 37Typical Installation of Single Reducing Valve with Noise Diffuser
the capacity of the pressurereducing valve, if it should failopen when discharging steamfrom the upstream pressure to theaccumulated pressure at the safe-ty valve. Any bypass line leakagemust also be accounted for.
Figure 38Typical Installationof Two ReducingValves in Parallel
Separator
PressureSensing Line
ReducingValve
Figure 39Two-Stage Pressure Reducing Valve Stationwith Bypass Arrangement to Operate EitherValve Independently on Emergency Basis
Safety Valve
Diffuser
Trap Set
Downstream Isolating Valve isneeded only with an alternativesteam supply into the L.P. System
Bypasses may be prohibitedby local regulation or byinsurance requirements
Parallel and Series Operation of Reducing Valves
21
Parallel OperationIn steam systems where loaddemands fluctuate through a widerange, multiple pressure controlvalves with combined capacitiesmeeting the maximum load per-form better than a single, largevalve. Maintenance needs, down-time and overall lifetime cost canall be minimized with this arrange-ment, Fig. 38 (page 20).
Any reducing valve must becapable of both meeting its maxi-mum load and also modulatingdown towards zero loads whenrequired. The amount of loadturndown which a given valve cansatisfactorily cover is limited, andwhile there are no rules whichapply without exception, if the lowload condition represents 10% orless of the maximum load, twovalves should always be pre-ferred. Consider a valve whichmoves away from the seat by 0.1inches when a downstream pres-sure 1 psi below the set pressureis detected, and which then pass-es 1,000 pounds per hour ofsteam. A rise of 0.1 psi in thedetected pressure then movesthe valve 0.01 inches toward the
seat and reduces the flow byapproximately 100 pph, or 10%.
The same valve might laterbe on a light load of 100 pph totalwhen it will be only 0.01 inchesaway from the seat. A similar risein the downstream pressure of0.1 psi would then close the valvecompletely and the change inflow through the valve which was10% at the high load, is now100% at low load. The figureschosen are arbitrary, but the prin-ciple remains true that instabilityor “hunting” is much more likelyon a valve asked to cope with ahigh turndown in load.
A single valve, when used inthis way, tends to open and close,or at least move further open andfurther closed, on light loads. Thisaction leads to wear on both theseating and guiding surfaces andreduces the life of thediaphragms which operate thevalve. The situation is worsenedwith those valves which use pis-tons sliding within cylinders toposition the valve head. Frictionand sticking between the slidingsurfaces mean that the valvehead can only be moved in a
series of discreet steps.Especially at light loads, suchmovements are likely to result inchanges in flow rate which aregrossly in excess of the loadchanges which initiate them.Load turndown ratios with piston-operated valves are almostinevitably smaller than wherediaphragm-operated valves arechosen.
Pressure Settingsfor Parallel ValvesAutomatic selection of the valveor valves needed to meet givenload conditions is readilyachieved by setting the valves tocontrol at pressures separated byone or two psi. At full load, orloads not too much below fullload, both valves are in use. Asthe load is reduced, the controlledpressure begins to increase andthe valve set at the lower pres-sure modulates toward the closedposition. When the load can besupplied completely by the valveset at the higher pressure, theother valve closes and with anyfurther load reduction, the valvestill in use modulates through itsown proportional band.
SYSTEMDESIGN
As part of a broad scope strategy to reduce operatingcosts throughout the refinery, a plan was established toeliminate all possible steam waste. The focus of the planwas piping leaks, steam trap failures and steam pressureoptimization.
Programs having been previously established todetect/repair steam trap failures and fix piping leaks, par-ticular emphasis was placed on steam pressureoptimization. Results from a system audit showed that aconsiderable amount of non-critical, low temperature trac-ing was being done with 190 psi (medium pressure)steam, an expensive overkill. It appeared that the mediumpressure header had been tapped for numerous smalltracing projects over the years.
SolutionRefinery engineers looked for ways to reduce pres-
sure to the tracer lines. Being part of a cost-cuttingexercise, it had to be done without spending large sums ofcapital money on expensive control valves. The self-con-
tained cast steel pressure regulators and bronze reducingvalves were chosen for the job. In 1-1/2 years, approxi-mately 40 pressure regulators and hundreds of bronzereducing valves have been installed at a cost of $250K.Annualized steam energy savings are $1.2M/year. Morespecifically, in the Blending and Shipping Division,$62,640 was saved during the winter of 1995, compared tothe same period in 1994.
Benefits• Low installed cost. The Spirax Sarco regulators and
bronze reducing valves are completely self-contained,requiring no auxiliary controllers, positioners, convert-ers, etc.
• Energy savings worth an estimated $1.2M/year.• The utilities supervisor who worked closely with Spirax
Sarco and drove the project through to successful com-pletion received company wide recognition and apromotion in grade.
Case in Action: Elimination of Steam Energy Waste
Parallel and Series Operation of Reducing Valves
22
This can be clarified by anexample. Suppose that a maxi-mum load of 5,000 lb/h at 30 psican be supplied through onevalve capable of passing 4,000lb/h and a parallel valve capableof 1,300 lb/h. One valve is set at29 psi and the other at 31 psi. Ifthe smaller valve is the one set at31 psi, this valve is used to meetloads from zero up to 1,300 lb/hwith a controlled pressure atapproximately 31 psi. At greaterloads, the controlled pressuredrops to 29 psi and the largervalve opens, until eventually it ispassing 3,700 lb/h to add to the1,300 lb/h coming through thesmaller valve for a total of 5,000lb/h.
There may be applicationswhere the load does not normallyfall below the minimum capacityof the larger valve. It would thenbe quite normal to set the 4,000lb/h valve at 31 psi and to supple-ment the flow through the 1,300lb/h valve at 29 psi in those fewoccasions when the extra capaci-ty was required.
Sometimes the split betweenthe loads is effectively unknown.It is usual then to simply selectvalves with capacities of 1/3 and2/3 of the maximum with thesmaller valve at the slightly high-er pressure and the larger one atthe slightly lower pressure.
Two-Stageor Series OperationWhere the total reduction in pres-sure is through a ratio of more than10 to 1, consideration should begiven to using two valves in series,Fig. 39 (page 20). Much willdepend on the valves being used,on the total pressure reductionneeded and the variations in theload. Pilot Operated controls havebeen used successfully with apressure turndown ratio as great as20 to 1, and could perhaps be usedon a fairly steady load from 100psig to 5 psi. The same valve wouldprobably be unstable on a variableload, reducing from 40 to 2 psi.
There is no hard and fastrule, but two valves in series willusually provide more accuratecontrol. The second, or LowPressure valve, should give the“fine control” with a modest turn-down, with due considerationbeing given to valve sizes andcapacities. A practical approachwhen selecting the turndown ofeach valve, that results in small-est most economical valves, is toavoid having a non-critical drop inthe final valve, and stay close tothe recommended 10 to 1 turn-down.
Series InstallationsFor correct operation of thevalves, some volume betweenthem is needed if stability is to beachieved. A length of 50 pipediameters of the appropriatelysized pipe for the intermediatepressure, or the equivalent vol-ume of larger diameter pipe isoften recommended.
It is important that the down-stream pressure sensing pipesare connected to a straight sec-tion of pipe 10 diametersdownstream from the nearestelbow, tee, valve or other obstruc-tion. This sensing line should bepitched to drain away from thepressure pilot. If it is not possibleto arrange for this and to still con-nect into the top of thedownstream pipe, the sensingline can often be connected to theside of the pipe instead.
Equally, the pipe between thetwo reducing valves shouldalways be drained through astream trap, just as any riserdownstream of the pressurereducing station should bedrained. The same applies wherea pressure reducing valve sup-plies a control valve, and it isessential that the connecting pipeis drained upstream of the controlvalve.
SYSTEMDESIGN
BypassesThe use of bypass lines andvalves should usually be avoided.Where they are fitted, the capaci-ty through the bypass should beadded to that through the wideopen reducing valve when sizingrelief valves. Bypass valves areoften found to be leaking steambecause of wiredrawing of theseating faces when valves havenot been closed tightly.
If a genuine need exists for abypass because it is essential tomaintain the supply of steam,even when a reducing valve hasdeveloped some fault or is under-going maintenance, considera-tion should be given to fitting areducing valve in the bypass line.Sometimes the use of a parallelreducing station of itself avoidsthe need for bypasses.
Back Pressure ControlsA Back Pressure regulator or sur-plussing valve is a derivative of apressure reducing valve, incorpo-rating a reverse acting pilot valve.The pressure sensing pipe is con-nected to the inlet piping so that thepilot valve responds to upstreampressure. Any increase in upstreampressure then opens the reverseacting pilot valve, causing the mainvalve to open, while a fall below theset pressure causes the main valveto close down, Fig. II-18 (page 92).
These controls are useful inflash steam recovery applicationswhen the supply of flash steammay at times exceed the demandfor it. The BP control can thensurplus to atmosphere anyexcess steam tending to increasethe pressure within the flashsteam recovery system, andmaintains the recovery pressureat the required level.
The control is also useful ineliminating non-essential loads inany system that suffers under-capacity at peak load times,leaving essential loads on line.
Back Pressure Controls arenot Safety Valves and must neverbe used to replace them.
How to Size Temperature and Pressure Control Valves
23
control may or may not be fullyopen. For three-port valves, it isthe difference in pressurebetween the two open ports.Working Pressure. The pressureexerted on the interior of a valveunder normal working conditions.In water systems, it is the algebra-ic sum of the static pressure andthe pressure created by pumps.Set Point. Pressure or tempera-ture at which controller is set.Accuracy of Regulation or“Droop”. Pressure reducingvalve drop in set point pressurenecessary to obtain the publishedcapacity. Usually stated for pilot-operated PRV’s in psi, and as a% of set pressure for direct-actingtypes.Hunting or Cycling. Persistentperiodic change in the controlledpressure or temperature.Control Point. Actual value ofthe controlled variable (e.g. airtemperature) which the sensor istrying to maintain.Deviation. The differencebetween the set point and themeasured value of the controlledvariable. (Example: When setpoint is 70°F and air temperatureis 68°F, the deviation is 2°F.)Offset. Sustained deviationcaused by a proportional control
taking corrective action to satisfy aload condition. (Example: If the setpoint is 70°F and measured roomtemperature is 68°F over a period,the offset is 2°F and indicates theaction of a proportional control cor-recting for an increase in heat loss.)Proportional Band or ThrottlingBand. Range of values whichcause a proportional temperaturecontrol to move its valve from fullyopen to fully closed or to throttlethe valve at some reduced motionto fully closed.Time Constant. Time requiredfor a thermal system actuator totravel 63.2% of the total move-ment resulting from anytemperature change at the sen-sor. Time increase when usingseparable well must be included.Dead Zone. The range of valuesof the controlled variable overwhich a control will take up nocorrective action.Rangeability. The ratio betweenthe maximum and minimum con-trollable flow between which thecharacteristics of the valve will bemaintained.Turn-Down Ratio. The ratiobetween the maximum normal flowand minimum controllable flow.Valve Authority. Ratio of a fullyopen control valve pressure dropto system total pressure drop.
SYSTEMDESIGN
Having determined the heating orcooling load required by theequipment, a valve must beselected to handle it. As the valveitself is only part of the completecontrol, we must be acquaintedwith certain terminology used inthe controls field:Flow Coefficient. The means ofcomparing the flow capacities ofcontrol valves by reference to a“coefficient of capacity.” The termCv is used to express this rela-tionship between pressure dropand flow rate. Cv is the rate offlow of water in GPM at 60°F, at apressure drop of 1 psi across thefully open valve.Differential Pressure. The differ-ence in pressure between the inletand outlet ports when the valve isclosed. For three-port valves, it isthe difference between the openand closed ports.Maximum Differential Pressure.The pressure difference betweeninlet and outlet ports of a valve,above which the actuator will notbe able to close the valve fully, orabove which damage may becaused to the valve, whichever isthe smaller.Pressure Drop. The differencebetween the inlet and outlet pres-sures when the valve is passingthe stated quantity. A self-acting
At a furniture manufacturing facility, the water used forbathing logs to prepare them for production was “rolling” inthe front of its containment tanks. The production manag-er had thought that the temperature had to be at least 212°F. Further examination showed the water’s temperatureto be 180°F. The water was “rolling” because the steam,entering the side of the tank, could not be absorbed by thewater before it rose to the surface in the front of the tank.
Cedar logs are cooked for 48 hours, in open top tanksbefore going through a veneer machine. The logs absorbthe hot water, making it easier to slice the wood into strips.The six log baths did not have any temperature controls.Twenty-five psig steam flowed through a 2" coupling intothe side of the tank to heat the water. With the tank sizebeing 12' x 12' x 6', the 105 cedar logs approximately 10'long occupy most of the space in the tank. River water or“condenser water” off of the turbine at 90°F is fed into thetank.
SolutionTwo temperature control valves to be open during start-upwith one closing as it approaches the desired cooking tem-perature. The second smaller valve continues to providesteam to the system until the set-point is reached. As addi-tional steam is required, the smaller valve supplies it. Asparge pipe was also sized and installed.
Benefits:• Payback of this system was less than 2 weeks on
materials and labor.
• Substantial cost savings due to improved energy use.
• Increased profitability by increasing productivity in thesteam system.
Case in Action: Log Bath-Furniture Manufacturing
Valve Sizing For SteamSatisfactory control of steam flow to giverequired pressures in steam lines orsteam spaces, or required temperaturesin heated fluids, depends greatly onselecting the most appropriate size ofvalve for the application.
An oversized valve tends to hunt, withthe controlled value (pressure or tempera-ture), oscillating on either side of thedesired control point. It will always seek tooperate with the valve disc nearer to theseat than a smaller valve which has to befurther open to pass the required flow.Operation with the disc near to the seatincreases the likelihood that any dropletsof water in the steam supply will give riseto wiredrawing. An undersized valve willsimply unable to meet peak load require-ments, startup times will be extended andthe steam-using equipment will be unableto provide the required output.
A valve size should not be deter-mined by the size of the piping intowhich it is to be fitted. A pressure dropthrough a steam valve seat of even afew psi means that the steam movesthrough the seat at high velocity. Valvediscs and seats are usually hardenedmaterials to withstand such conditions.The velocities acceptable in the pipingare much lower if erosion of the pipesthemselves is to be avoided. Equally, thepressure drop of a few psi through thevalve would imply a much greater pres-sure drop along a length of pipe if thesame velocity were maintained, andusually insufficient pressure would beleft for the steam-using equipment to beable to meet the load.
Steam valves should be selected onthe basis of the required steam flowcapacity (lb/h) needed to pass, the inletpressure of the steam supply at thevalve, and the pressure drop which canbe allowed across the valve. In mostcases, proper sizing will lead to the useof valves which are smaller than thepipework on either side.
Calculating Condensate LoadsWhen the normal condensate load is not known, the load can beapproximately determined by calculations using the following formula.
General Usage FormulaeHeating water with steam (Exchangers)*
lb/h Condensate = GPM x (1.1) x Temperature Rise °F2
Heating fuel oil with steam
lb/h Condensate = GPM x (1.1) x Temperature Rise °F4
Heating air with steam coils
lb/h Condensate = CFM x Temperature Rise °F800
Steam Radiation
lb/h Condensate = Sq. Ft. EDR4
*Delete the (1.1) factor when steam is injected directly into water
Specialized ApplicationsSterilizers, Autoclaves,
Retorts Heating Solid Material
lb/h Condensate = W x Cp x ∆TL x t
W = Weight of material—lbs.Cp = Specific heat of the material(∆)T = Temperature rise of the material °FL = Latent heat of steam Btu/lbt = Time in hours
Heating Liquids in Steam JacketedKettles and Steam Heated Tanks
lb/h Condensate = G x s.g. x Cp x (∆)T x 8.3L x t
G = Gallons of liquid to be heateds.g. = Specific gravity of the liquidCp = Specific heat of the liquid(∆)T = Temperature rise of the liquid °FL = Latent heat of the steam Btu/lbt = Time in hours
Heating Air with Steam;Pipe Coils and Radiation
lb/h Condensate = A x U x (∆)TL
A = Area of the heating surface in square feetU = Heat transfer coefficient (2 for free convection)(∆)T = Steam temperature minus the air temperature °FL = Latent heat of the steam Btu/lb
How to Size Temperature and Pressure Control Valves
24
SYSTEMDESIGN
Steam Jacketed Dryers
lb/h Condensate = 1000 (Wi - Wf) + (Wi x ∆T)L
Wi = Initial weight of the material—lb/hWf = Final weight of the material—lb/h(∆)T = Temperature rise of the material °FL = Latent heat of steam Btu/lbNote: The condensate load to heat the equipment must be addedto the condensate load for heating the material. Use same formula.
How to Size Temperature and Pressure Control Valves
25
1. For LiquidsCv = GPM Sp. Gr.
√Pressure Drop, psiWhere Sp. Gr. Water = 1GPM = Gallons per minute
2. For Steam (Saturated)a. Critical Flow
When ∆P is greater thanFL
2 (P1/2)
Cv = W 1.83 FLP1
b. Noncritical FlowWhen ∆P is less thanFL
2 (P1/2)
Cv = W 2.1√∆P (P1 + P2)
Where: P1 = Inlet Pressure psiaP2 = Outlet Pressure psiaW = Capacity lb/hrFL = Pressure Recovery Factor
(.9 on globe pattern valves for flow to open)(.85 on globe pattern valves for flow to close)
3. For Air and Other Gasesa. When P2 is 0.53 P1 or less,
Cv = SCFH √Sp. Gr.30.5 P1
Where Sp. Gr. of air is 1.SCFH is Cu. ft. Free Air perHour at 14.7 psia, and 60°F.
b. When P2 is greater than 0.53 P1,
Cv = SCFH √Sp. Gr.61 √(P1 - P2) P2
Where Sp. Gr. of air is 1.SCFH is Cu. Ft. Free Air per Hour at 14.7 psia, and 60°F.
4. Correction for Superheated SteamThe required Valve Cv is the Cv from theformula multiplied by the correction factor.Correction Factor = 1 + (.00065 xdegrees F. superheat above saturation)Example: With 25°F of Superheat,
Correction Factor= 1 + (.00065 x 25)= 1.01625
5. Correction for Moisture ContentCorrection Factor = √Dryness FractionExample: With 4% moisture,
Correction Factor = √1 - 0.04= 0.98
6. Gas—Correction for TemperatureCorrection Factor = 460 + °F
√ 520Example: If gas temperature is 150°F,Correction Factor = 460 + 150
√ 520= 1.083
SYSTEMDESIGN
Temperature Control Valve SizingAfter estimating the amount of steam flow capacity(lbs/hr) which the valve must pass, decide on thepressure drop which can be allowed. Where the min-imum pressure in a heater, which enables it to meetthe load, is known, this value then becomes thedownstream pressure for the control valve. Where itis not known, it is reasonable to take a pressure dropacross the valve of some 25% of the absolute inletpressure. Lower pressure drops down to 10% cangive acceptable results where thermo-hydraulic con-trol systems are used. Greater pressure drops canbe used when it is known that the resulting down-stream pressure is still sufficiently high. However,steam control valves cannot be selected with outputpressures less than 58% of the absolute inlet pres-
sure. This pressure drop of 42% of the absolutepressure is called Critical Pressure Drop. The steamthen reaches Critical or Sonic velocity. Increasing thepressure drop to give a final pressure below theCritical Pressure gives no further increase in flow.
Pressure Reducing Valve SizingPressure reducing valves are selected in the sameway, but here the reduced or downstream pressurewill be specified. Capacity tables will list the SteamFlow Capacity (lb/h) through the valves with givenupstream pressures, and varying downstream pres-sures. Again, the maximum steam flow is reached atthe Critical Pressure Drop and this value cannot beexceeded.
It must be noted here that for self-acting regula-tors, the published steam capacity is always givenfor a stated “Accuracy of Regulation” that differsamong manufacturers and is not always the maxi-mum the PRV will pass. Thus when sizing a safetyvalve, the Cv must be used.
Cv ValuesThese provide a means of comparing the flow capac-ities of valves of different sizes, type ormanufacturer. The Cv factor is determined experi-mentally and gives the GPM of water that a valve willpass with a pressure drop of 1 psi. The Cv requiredfor a given application is estimated from the formu-lae, and a valve is selected from the manufacturerscatalog to have an equal or greater Cv factor.
Temperature Control Valves for Steam Service
26
Temperature Control ValvesFor Steam ServiceAs with pressure reducing valves,temperature control valves canbe divided into three groups.Installation of these valves arethe same as pressure reducingstyles in that adequate protectionfrom dirt and condensate must beused as well as stop valves forshutdown during maintenanceprocedures. A noise diffuserand/or a safety valve would nor-mally not be used unless acombination pressure reducingand temperature control, isinstalled. See PRV station com-ponents on page 20 for moreinformation.
Direct Operated ValvesThe direct operated type asshown in Fig. 40 are simple indesign and operation. In thesecontrols, the thrust pin movementis the direct result of a change intemperature at the sensor. Thismovement is transferred throughthe capillary system to the valve,thereby modulating the steamflow. These valves may also beused with hot water. Such a sim-ple relationship between
temperature changes and valvestem movement enables sensorand valve combinations to givepredictable valve capacities for arange of temperature changes.This allows a valve to be selectedto operate with a throttling bandwithin the maximum load propor-tional band. See appropriatetechnical sheets for specific valveproportional bands.
Choice of Proportional Bandis a combination of accuracy andstability related to each applica-tion. However, as controlaccuracy is of primary impor-tance, and as direct operatedcontrols give constant feedbackplus minute movement, we canconcentrate on accuracy, leavingthe controller to look after stabili-ty. Generally, to give light loadstability, we would not select aProportional Band below 2°F.Table 9 gives the span of accept-able Proportional Bands for somecommon heat exchanger applica-tions.
Pilot Operated ValvesGreater steam capacities areobtained using pilot operatedvalves, along with greater accura-
cy due to their 6°F proportionalband. Only a small amount ofsteam has to flow through the pilotto actuate the main diaphragmand fully open the valve. Onlyvery small changes of movementwithin the sensor are necessary toproduce large changes in flow.This results in accurate controleven if the upstream steam pres-sure fluctuates.
Both direct and pilot operatedvalve types are self-containedand do not require an externalpower source to operate.
SYSTEMDESIGN
An office paper product manufacturer uses steam in itsprocess for a dry coating applied to the paper. Using apocket ventilation system, air is blown across the paper asit moves through the dryer cans.
The original design included inverted bucket typetraps on the outlet of the steam coils, but the coils are inoverload boxes where outdoor and indoor air mix. Thesteam supply is on a modulating control with maximumpressure of 150 psi. The steam traps discharge into a com-mon header that feeds to a liquid mover pump. The pumphad a safety relief valve on its non-vented receiver.
Problems observed included the inability to maintaindesired air temperatures across the machines, high backpressure on the condensate return system, the doors onthe coil boxes had to be opened to increase air flowsacross the coils, paper machine had to be be slowed downto improve dryness, steam consumption was way up,water make-up was up and vent lines were blowing livesteam to the atmosphere.
Solution:A pump trap combination was installed on five of the ninesections using a pressure regulator for motive steam sup-
ply reduction to the pumps. Float & thermostatic traps withleak detection devices were also installed for efficiency.Closed doors were then put on the coil boxes.
The back pressure on the return system dropped to anacceptable and reasonable pressure and the steam con-sumption also dropped. Temperature control was achievedand maintained and production increased from 1,000 feetper minute on some products to 1,600 feet per minute.They switched all five sections of the paper coater to 1" lowprofile Pressure Powered Pump with cast iron float & ther-mostatic steam traps. This manufacturer also switchedfrom inverted buckets on heating units to float and thermo-static steam traps with leak detection devices and replacedseveral electric pumps and the liquid mover with PressurePowered Pumps. Replaced all 16 inverted bucket traps onpaper coater with float and thermostatic steam traps withleak detection devices.
Benefits:• Production Increased • Trap failure went from 40% to 14%.• Over a half-million dollars in steam saved during first
year of operation
Case in Action: Dry Coating Process
Table 9 Acceptable Proportional Bandsfor Some Common Applications
ProportionalApplication Band °F
Domestic Hot Water 7-14Heat Exchanger
Central Hot Water 4-7
Space Heating 2-5(Coils, Convectors,Radiators, etc.)
Bulk Storage 4-18
Plating Tanks 4-11
Temperature Control Valves for Steam Service
27
Pneumatically OperatedValves.Pneumatically operated tempera-ture control valves as shown inFig. II-21 (page 93), provideaccurate control with the ability tochange the setpoint remotely. Acontroller, through a sensor,adjusts the air signal to the valveactuator or positioner which, inturn, opens or closes the valve asneeded. Industry demands formore accurate control of temper-ature and computer interfacing ismaking the pneumatically operat-ed valves grow within themarketplace.
Installation ofTemperature Control ValvesThe operation and longevity ofthese valves depends greatly onthe quality of the steam which is fedto them. The components of a tem-perature control valve station aresame as for a pressure reducingvalve, see page 19. In addition,attention must be paid to the loca-tion of the temperature sensingbulb. It should be completelyimmersed in the fluid being sensed,with good flow around the bulb,and, if used with a well, someheatsink material in the well to dis-place the air which prevents heattransfer. The capillary tubing shouldnot be in close proximity to high orlow temperatures and should notbe crimped in any fashion.
Heating Liquids By DirectSteam InjectionWhere noise and dilution of theproduct are not problems thendirect steam injection can beused for heating. Steam injectionutilizes all of the latent heat of thesteam as well as a large portionof the sensible heat. Two meth-ods, sparge pipes and steaminjectors, are used to direct andmix the steam with the product.
Sparge Pipe SizingA sparge pipe is simply a perforatedpipe used to mix steam with a fluidfor heating. Sizing of this pipe isbased on determining the requiredsteam flow, selecting a steam pres-sure within the pipe (normally lessthan 20 psig for non-pressurizedvessels), and calculating the num-ber of holes by dividing the requiredsteam flow by the quantity of steamthat will flow through each spargehole of a specific diameter as deter-mined from Fig. 42. Holes largerthan 1/8" diameter are used only onrelatively deep tanks where thelarger steam bubbles emitted willhave time to condense beforebreaking the liquid surface, orwhere the required number of 1/8"dia. holes becomes unreasonablygreat. The sparge holes should bedrilled 30° below the horizontalspaced approximately 6" apart andone hole at the bottom to permitdrainage of liquid within the pipe,see Fig. 41. The sparge pipe shouldextend completely across the ves-sel for complete and even heating.
SYSTEMDESIGN
Figure 41The sparge pipe diameter can be determined using Fig. 1 (page 4),limiting the maximum velocity to 6000 ft/min. A typical installation isshown on Fig II-42 (page 105).
Figure 40Operating Principle ofDirect Operated Valves
ValveMovement
Thrust Pin Movement(Movement caused byadding temp to sensor)
Sensor Bulb
Capillary
Add 1°F to Sensor
Valve Housing
Thrust Pin
6"
30°
Figure 42Steam Flow through Sparge Holes
50
40
30
20
10
706050403020100Sparge Pipe Pressure psig
Ste
am F
low
- lb
s. p
er h
r.
3/16" Dia.
1/8" Dia.
3/32" Dia.
Temperature Control Valves for Steam Service
28
Steam InjectorUnlike a sparge pipe, a steaminjector is a manufactured devicethat draws in the cold liquid,mixes it with steam within theinjector nozzle and distributes thehot liquid throughout the tank.
SYSTEMDESIGN
Fine steam filtration in the preparation of cheese production isimportant to the quality of the final product. Because the pro-ducer of cheese products was heating cheese vat washdownwater by direct steam injection, a filtration device was addedto enhance product quality by filtering out the particulates.
While pleased with this simple method of heating, therewas some concern that any particulates entering the wash-down water during steam injection may ultimately contaminatethe vats being cleaned, affecting the cheese production.
SolutionDirect steam injection was the best solution for the cheeseproducer, but the concern about the contamination wasvery important. • A separator was installed in the incoming steam supply
line, which removes a high percentage of the entrainedmoisture. A fine mesh screen strainer was installed toremove solid particulate matter.
• A pneumatically actuated two port valve was installed tocontrol tank temperature. The unit throttles the flow ofsteam to the tank based on the signal being transmittedby the temperature controller.
• Having removed the entrained moisture and majority of par-ticulate matter from the steam supply, a cleanable CSF16
stainless steel steam filter was installed which is capable ofremoving finer particles smaller than 5 microns in size.
• A vacuum breaker was added to the system in order toprevent any of the heated water being drawn back upinto the filter during certain periods of operation.
• A stainless steel injector system was installed which iscapable of efficiently mixing large volumes of high pressure steam with the tank contents with little noise ortank vibration. (The customer stipulated the reduction ofnoise levels in the production facility.)
Benefits:• Guaranteed steam purity and assured compliance with
the 3-A Industry Standard• Inexpensive installation compared with alternative heat
exchanger packages available• Cleanable filter element for reduced operating costs
(replacement element and labor costs).• Accurate temperature control using components of the
existing system• Quiet and efficient mixing of the steam and the tank contents• Product contamination is minimized, the cost of which
could be many thousands of dollars, loss of productionor even consumer dissatisfaction.
Case in Action: Cheese Production
The circulation induced by theinjector will help ensure thoroughmixing and avoid temperaturestratification. See Fig. II-43 (page105) for a typical injector installa-tion. Other advantages of the
injector over a sparge pipe isreduced noise levels and the abil-ity to use high pressure steam upto 200 psig. Refer to applicabletechnical information sheets forsizing and selection information.
Temperature control valves forliquid service can be divided intotwo groups. Normally associatedwith cooling, these valves canalso be used on hot water.
Direct Operated ValvesThree types are available for liq-uid service and a selection wouldbe made from one of the follow-ing styles.2-Port Direct-Acting.Normally open valve that the ther-mal system will close on risingtemperature and used primarilyfor heating applications.2-Port Reverse-Acting.Normally closed valve which isopened on rising temperature.For use as a cooling control,valve should contain a continu-ous bypass bleed to preventstagnate flow at sensor.
3-Port Piston-Balanced.This valve is piped either forhot/cold mixing or for divertingflow between two branch lines.
Pneumatically OperatedValvesAs with direct operated valves,the pneumatically operated typeshave the same three groups. Themajor difference is they requirean external pneumatic or electric(through a positioner or convert-er) signal from a controller.
Heating And Cooling LoadsFormulas for calculating the heat-ing or cooling load in gallons perminute of water are:Heating Applications:a. Heating water with water
Heating water GPM required= GPM (Load) x TR
∆T1
b. Heating oil with waterHeating water GPM required= GPM (Load) x TR
2 X ∆T1
c. Heating air with waterHeating water GPM required= CFM x TR
400 x ∆T1
Cooling Applications:d. Cooling air compressor
jacket with waterCooling Water GPM required= 42.5 x HP per Cylinder
8.3 x ∆T2
Where:GPM = Gallons per minute waterTR = Temperature rise of
heated fluid, °FCFM = Cubic feet per minute Air∆T1 = Temperature drop of
heating water, °F∆T2 = Temperature rise of
cooling water, °F
Temperature Control Valves for Liquid Service
Temperature Control Valves for Liquid Service
29
Water Valve SizingWater valve capacity is directlyrelated to the square root of thepressure drop across it, not thestatic system pressure. Knowingthe load in GPM water or anyother liquid, the minimum valveCv required is calculated from theallowable pressure drop (∆P):Cv = GPM S.G.
√ ∆P derived from...GPM(Water) = Cv √ ∆P(Other SG Liquids)GPM = Cv ∆P
√ S.G.
If the allowable differential pres-sure is unknown, the followingpressure drops may be applied:• Heating and Cooling systems
using low temperature hotwater (below 212°F)—Size valve at 1 psi to 2-1/2 psidifferential.
• Heating Systems using waterabove 212°F—Size valve on a 2-1/2 to 5 psidifferential.
• Water for process systems—Size valve for pressure dropof 10% up to 20% of the sys-tem pressure.
• Cooling Valves—Size for allowable differentialup to full system pressuredrop when discharging toatmosphere. Be sure tocheck maximum allowablepressure drop of the valveselected. A bellows-balancedtype may be required.
Using Two-Port andThree-Port ValvesOnly two-port valves are used onsteam systems. However, whendealing with controls for water wecan select either two-port orthree-port valves. But we mustconsider the effects of both typeson the overall system dynamics.
A three-port valve, whethermixing or diverting, is fairly closeto being a constant volume valveand tends to maintain constantpressure distribution in the sys-tem, irrespective of the position ofthe valve.
If a two-port valve were used,the flow decreases, the valvecloses and the pressure or headacross it would increase. Thiseffect is inherent in the use oftwo-port valves and can affect theoperation of other subcircuits.
Furthermore, the waterstanding in the mains will oftencool off while the valve is closed.When the valve reopens, thewater entering the heat exchang-er or load is cooler thanexpected, and it is some timebefore normal heating can com-mence. To avoid this, a smallbypass line should be installedacross the supply and returnmains. The bypass line should besized to handle flow rate due tomains losses but in the absenceof information, the bypass shouldbe sized for 10% of the designflow rate.
SYSTEMDESIGN
Figure 43Three-Port Mixing Valve in a Closed Circuit(Constant Volume, Variable Temperature)
Figure 43AThree-Port Diverting Valve in a Closed Circuit(Constant Temperature, Variable Volume)
ConstantlyOpen Port
BalanceValve
C
HeatingSystem
Pump
Pump
ConstantlyOpen Port
BalanceValve
Three-Port Valve
Boiler
Boiler
A
A
B
B
O
Z X
Three-Port Valve
O
X Z
C
HeatingPlant orProcessEquipment
Temperature Control Valves for Liquid Service
30
Mixing And DivertingThree-Port ValvesA three-port temperature controlhas one port that is constantlyopen and it is important that thecirculating pump is always posi-tioned on this side of the system.This will prevent the risk of pump-ing against dead end conditionsand allow correct circulation to doits job.
The valve can be used eitherto mix or divert depending uponhow it is piped into the system. Amixing valve has two inlets andone outlet, a diverting valve hasone inlet and two outlets.
Fig. 43 illustrates the three-port valve used as a mixing valvein a closed circuit. It has two inlets(X and Z) and one outlet (O) whichis the permanently open port. PortX is the port open on startup fromcold, while Port Z will normally beclosed on startup from cold. Theamounts of opening in Ports X andZ will be varied to maintain a con-stant outlet temperature from PortO. Thus a certain percentage ofhot boiler flow water will enterthrough Port X to mix with a corre-sponding percentage of coolerreturn water via Port Z.
When the three-port valve isused to blend cold supply waterwith hot water which may be from
another source, for use in show-ers or similar open circuits whereall the water does not recirculate,it is essential that the pressure ofthe supplies be equal. For theseapplications, it is recommendedthat both the X and Z ports be fit-ted with check valves to preventany scalding or other harmfulback-flow condition.
With the valve connected asshown in Fig. 43A, we now havea diverting arrangement. Thevalve has one inlet and two out-lets. Hot water enters Port O andis either allowed through Port X tothe equipment or through Port Zto return to the boiler.
The Need for BalancingThe action of a three-port valve ina closed circuit system, whethermixing or diverting, tends tochange the pressure conditionsaround the system much less thandoes a two-port valve. This stabili-ty is increased greatly when abalancing valve is fitted in thebypass (or mixing connection)line. Not fitting a flow balancingvalve may result in short circuitingand starvation of other subcircuits.
The balancing valve is set sothat the resistance to flow in thebypass line equals or exceeds thatin the load part of the subcircuit.
In Fig. 43, the balance valvemust be set so that the resistanceto flow in line B-Z is equal to theresistance to flow in line B-A-X. InFig. 43A, resistance B-Z mustequal resistance X-C-B.
Makeup Air Heating CoilsAir heating coils in vented con-densate return systems,especially preheat coils suppliedwith low pressure steam modulat-ed by a control valve, can presentdifficulties in achieving satisfacto-ry drainage of condensate. Thereis no problem at full load withproperly designed equipment, butpart load conditions often lead toflooding of the coils with conden-sate, followed by waterhammer,corrosion and sometimes byfreeze-up damage. These prob-lems are so widespread that it isworth examining their causes andremedies in some detail.
Coil ConfigurationsThe coils themselves are usuallybuilt with a steam header and acondensate header joined byfinned tubes. The headers may beboth at one side of the unit, withhairpin or U tubes between them,or sometimes an internal steamtube is used to carry the steam tothe remote end of an outer finnedtube. Vertical headers may beused with horizontal finned tubes,
SYSTEMDESIGN
Hydrogen gas is an important ingredient to many oil refin-ing processes. Large multi-stage compressors are locatedin operating sections throughout the refinery. Considerableattention is paid to maintaining gas quality, and keepingliquid from accumulating in the system.
The telltale signs of entrained liquid became evidentas a high-pitched whistling noise was heard coming fromthe compressor sections. It was determined to be theresult of poor cooling water temperature control. The cool-ing water/Glycol mixture leaving the heat exchanger at95°F, circulating through the compressor jacket was caus-ing excess hydrogen condensing on the cold surfaces ofjacket walls. It’s important to maintain the 95°F heatexchanger outlet temperature to assure that sufficiently-cool water/Glycol is supplied to the compressor sectionsnecessary for proper heat transfer.
SolutionA 2" temperature control with adjustable bleed and a sens-ing system was installed on the cooling water/Glycol outletpiping from three stages for each of two compressors.They were set to maintain a discharge temperature of140°F. This had the effect of holding back Glycol in thejacket sufficiently to prevent excess hydrogen condensingwhile, at the same time, maintaining necessary cooling.
Benefits• Reduced energy consumption as hydrogen condensing
is reduced.• Installation of a self-contained control was far less
expensive than a more sophisticated pneumatic typethat was also under consideration.
• System start-up was fast because of the easily-adjust-ed, pre-calibrated sensing system.
• Accurate process temperature control of each jacketresulted from having separate controls on each.
Case in Action: Hydrogen Compressor Cooling Jacket Temperature Control
Makeup Air Heating Coils
31
or sometimes horizontal headersat the bottom of the unit supplyvertical finned tubes. The alterna-tive arrangement has the headersat opposite sides of the unit, eitherhorizontally at top and bottom orvertically at each side.
While each different arrange-ment has its own proponents,some general statements can bemade, including the fact that evenso-called “freeze-proof” coils canfreeze if not properly drained ofcondensate. In “horizontal” coils,the tubes should not be horizontalbut should have a slight fall frominlet to outlet so that condensatedoes not collect in pools butdrains naturally. Steam inlets to“horizontal” headers may be atone end or at mid length, but withvertical headers the steam inlet ispreferably near the top.
Venting Air From CoilsAs steam enters a coil it drives airahead of it to the drain point, or toa remote area furthest from theinlet. Coil size and shape mayprevent a good deal of air fromreaching the trap and as steamcondenses, a film of air remainsreducing heat transfer. Coils witha center inlet connection make itmore difficult to ensure that air ispushed from the top tubes, thesteam tending to short circuit pastthese tubes to the condensateheader. Automatic air venting ofthe top condensate header ofthese coils is essential. With otherlayouts, an assessment must bemade of the most likely part of theunit in which air and noncondens-able gases will collect. If this is atthe natural condensate drainpoint, then the trap must havesuperior air venting capability anda Float-Thermostatic type is thefirst choice. When an invertedbucket or other type with limitedair capacity is used, an auxiliaryair vent should be piped in paral-lel above the trap. As a generalrule, a thermostatic vent and vac-uum breaker are desirable onmost coils to prevent problems.
Waterlogged CoilsThe most common cause of prob-lems, however, is lack of pressurewithin the steam space under partload conditions to push conden-sate through the traps, especiallyif it is then to be lifted to a returnline at high level or against a backpressure. System steam pres-sure lifts condensate, not thetrap, and is generally not appreci-ated how quickly the pressurewithin the steam space can bereduced by the action of the con-trol valve. When pressure used topush condensate through thetraps is lost, the system “stalls”and as condensate backs up intothe coil, waterlogging problems ofhammering, temperature stratifi-cation, corrosion and freeze-upbegin. The coil must be fitted witha vacuum breaker so that con-densate is able to drain freely tothe trap as shown in Fig. II-27(page 97) and from the trap bygravity to a vented receiver andreturn pump. This is especiallyimportant when incoming air tem-perature can fall below freezing.With low coils, this may requirethe pump to be placed in a pit orlower floor. How to determine
“system stall” conditions and thesolution for draining coils to apressurized return is coveredlater in this manual.
Vacuum BreakerAnd Trap LocationA vacuum breaker ensures thatsome differential pressure canalways exist across a trap thatdrains by gravity but any elevationof condensate after the trapreduces the hydraulic head avail-able. Heating is done using anatmospheric air/steam mixture socoil air venting is most important.A vacuum breaker should be fittedto the steam supply pipe, betweenthe temperature control valve andthe coil inlet. It is not recommend-ed to fit a vacuum breaker on thesteam trap where the hydraulichead of water used to push con-densate through the trap wouldhold the vacuum breaker closed.
In systems where the returnpiping is kept under vacuum, areversed swing check valveshould be used and piped toequalize any coil vacuum not toatmosphere, but to the dischargeside of the trap.
SYSTEMDESIGN
Figure 44Air Heater Coils
FinnedTubes
InletInlet
Inlets
Outlets
Outlets
OutletOutlet
Inlet
Air VentLocation
Alternative Steam Inlet andCondensate Outlet Connecitons
On Coils with Verticalor Horizontal Headers
Makeup Air Heating Coils
32
The steam trap must handlelots of air and drain condensateat saturated steam temperaturecontinuously while the load andpressure are changing and thus aFloat-Thermostatic type is recom-mended for all air heating coils.The trap is mounted below thecondensate outlet from the coilwith a vertical drop giving enoughhydraulic head to enable a suit-able size to be selected. A 14"head should be the minimum andrepresents about 1/2 psi, a 28"head about 1 psi, and to reducepossibility of freeze-up, a drop of3 ft. to the trap is recommended.
Preheat/Reheat CoilsThe preheat/reheat coil hookupshown in Fig. II-26 (page 96) mayemploy a direct-acting temperaturecontrol or with larger coils, a quick-er responding pilot-operated typewith a closer control band is rec-ommended. This arrangementallows filtration and perhaps humid-ification of the air to be carried outat the controlled preheat tempera-ture, and the reheat coil brings thedry bulb temperature of the condi-tioned air to the required value fordistribution. The preheat coil isused to heat outside air up to the
intermediate temperature but asoutside temperature increases, thetemperature control lowers thesteam pressure in the preheat coiland condensate drainage tends toslow down. If the coil is being usedwhere design loads occur at sub-zero temperatures, there cansometimes be only atmosphericpressure in the coil, although the airpassing over it is still cold enoughto lead to freeze-up problems.
This difficulty is greatlyreduced if the temperature sensorcontrolling the steam supply to thepreheat coil is set to the neededdistribution temperature. Part loadconditions would then lead firstly tolowering the steam pressure in thereheat coil, where freezing will notoccur, but pressure is maintainedin the preheat coil until outside airtemperatures are above the dan-ger point. Such an arrangementreduces freeze-up problems inmany instances on existing instal-lations, at minimal cost.
Corrosion AndWaterhammer ProblemsCondensate mixed with airbecomes corrosive and assumingthe boiler water treatment is satis-
factory, coil corrosion problemsare usually due to condensateregularly backing up or lying stag-nant on the bottom of the tubesduring shutdown. If the coil istrapped correctly, the most likelycause is an overhead returnwhich prevents the coil fromdraining. One remedy for this is tofit a liquid expansion steam trap atthe lowest piping level, as shownin Fig. II-26 (page 96), set to openwhen the temperature dropsbelow 90°F. The coil then drainsonly cold condensate to a sewer.
In high pressure systemswhere waterhammer on startupremains troublesome, a “safetydrain” trap is sometimes used. Thisconsists of a stock 15 psi ratedinverted bucket trap fitted abovethe main trap which discharges todrain whenever coil pressure islow, but due to its design locks shutat higher pressure. While this isuseful on pressurized mains, thesafety trap may require a pressureconsiderably higher than its nomi-nal rating to lock shut and onmodulating service a considerableamount of condensate may bewasted. This makes the combina-tion pump/trap a more viablesolution to this problem.
SYSTEMDESIGN
Typical storage buildings are extremely large and difficultto heat. This example in specific has three floors withapproximately 486,000 ft2 of floor space and heated with150 air handling units. These units are comprised of bayheaters, overhead door heaters and administrative officearea heaters. The minimum steam supply pressure to all ofthem is 20 psig and are pneumatically controlled.
In the preceding 12 month period, $201,000 wasspent on labor and materials to repair damaged coils. Thecommon problem was condensate standing in the coils,unable to drain, causing erosion due to presence of car-bonic acid and bulging/splitting as a result of freezing.
SolutionStarting with a training session at the facility that addressedthis problem and typical solutions, Spirax Sarco’s localsales office implemented a “Cooperative Research andDevelopment Agreement” (CRDA). The purpose of theagreement was to test a proposed solution includingPressure Powered Pumps™ and Pump/Trap combinationsto eliminate system stall, thereby assuring thorough con-densate drainage, regardless of supply air temperature,control valve turn-down or over-sized heaters.
A test was conducted on four air handling units. Oneunit was hooked up as usual, without Pressure Powered
Pump™ drainage systems. The other three were drainedby either open or closed loop PPP systems. Four days intothe test and the unit without a PPP drainage system hadthree frozen coils. It was found that as outside supply airtemperature dropped below 36˚F, it was necessary toclose outside dampers and use 100% recirculated air, orthe coils would freeze. The three units drained by PPP sys-tems continued operating trouble-free.
BenefitsEmployee Safety• Improved indoor air quality through the use of a higher
percentage of outside air supply.• Reduced chance of injury by eliminating water leakage on
the floor from broken coils and subsequent slippage.• Fewer burns because there are fewer steam leaks.• Greater employee awareness of hazards because of
training.Cost Savings• Reduced steam and condensate losses resulting in
energy savings.• Reduced cost for management support (paper-work).• Cost savings of up to 30% above the initial installation
cost in a 12 month period.
Case in Action: Air Handling System Steam Coil Drainage
Draining Temperature Controlled Steam Equipment
33
Makeup air heating coils andother heat exchange equipmentwhere the steam supply pressureis modulated to hold a desiredoutflow temperature must alwaysbe kept drained of condensate.Fitting a vacuum breaker andsteam trap, no matter what thesize, does not always result introuble-free operation and prob-lems with noisy, hammering,corroded and especially frozencoils are well documented. Theseproblems are the result of coilflooding at some point wheneither:a. Incoming makeup air increas-
es above minimum designtemperature, or
b. Flow rate through an exchang-er decreases below themaximum equipment output.In a steam system, tempera-
ture regulation actually meanscontrolling the pressure. Under par-tial load conditions, the steamcontroller, whether self-acting,pneumatic or any other type,reduces the pressure until the nec-essary trap differential is eliminated,the system “stalls,” and steam coilsbecome waterfilled coils.
Conditions Creating“System Stall”With the steam equipment andthe operating pressure selected,the load at which any systemstalls is a function of how closethe equipment is sized to theactual load and any condensateelevation or other back pressurethe trap is subject to.
Other less obvious things canalso seriously contribute to “sys-tem stall”; for instance, overlygenerous fouling factors andequipment oversizing. As anexample, a fouling factor of “only”.001 can result in a coil surfacearea increase of 50% (See Table10). Equipment oversizing caus-es the system to stall faster. Thisis particularly the case when theheating equipment is expected torun considerably below “designload.”
Saturated steam temperatureis directly related to its pressure
and for any load requirement, thecontrol valve output is determinedby the basic heat transfer equa-tion, Q = UA x ∆T. With “UA” for asteam-filled coil a constant, theamount of heat supplied, “Q”, isregulated by the “∆T,” the logmean temperature difference(LMTD) between the heated air orliquid and saturated steam tem-perature at the pressure deliveredby the valve. Thus, the steampressure available to operate thetrap is not constant but varies withthe demand for heat from almostline pressure down through sub-atmospheric, to completeshutdown when no heat isrequired. Actual differential acrossthe trap is further reduced whenthe heating surface is oversizedor the trap must discharge againsta back pressure. Knowing theseconditions, the system must bedesigned accordingly.
Plotting A “Stall Chart”An easy way to determine theconditions at which drainage
problems will occur, and preventthem at the design stage is to usethe “stall chart” shown in Fig. 45.
The steam supply pressure isshown on the vertical axis, withcorresponding temperatures onthe opposite side, and the plot willindicate graphically what will occurfor any percentage of the designload. This method provides a fairlyaccurate prediction of stall condi-tions even though the chart uses“arithmetic” rather than “log mean”temperature difference.
SYSTEMDESIGN
Table 10:Percentage Fouling AllowanceVelocity Fouling Factor
in Ft./Sec. .0005 .0011 1.14 (14%) 1.27 (27%)
2 1.19 (19%) 1.38 (38%)
3 1.24 (24%) 1.45 (45%)
4 1.27 (27%) 1.51 (51%)
5 1.29 (29%) 1.55 (55%)
6 1.30 (30%) 1.60 (60%)
7 1.31 (31%) 1.63 (63%)
Figure 45: Stall Chart
100 90 80 70 60 50 40 30 20 10 0
400
380
360
340
320
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25" Inch
es V
acu
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Draining Temperature Controlled Steam Equipment
34
An example plot is shown onFig. 46 for a coil where air is heat-ed to 80°F and the trap mustdischarge against back pressure.Step 1. The system is designed for100% load when air enters at 0°F(T1) and there is 0% load when airenters at 80°F (T2). Draw line(T1/T2) connecting these points.Step 2. At maximum load, thearithmetic mean air temperature(MT) is 40°F. Locate (MT) on line(T1/T2), extend horizontally to 0%load, and identify as (MT1).Step 3. Allowing for pressuredrop, the control valve has beensized to supply 25 psig steam tothe coil at 100% load. This pres-sure is (P1) and has a steamtemperature of 267°F. Mark (P1)and draw line (P1/MT1).Line (P1/MT1) approximates thesteam supply at any load condi-tion and the coil pressure is belowatmospheric when it drops belowthe heavy line at 212°F. In a grav-ity system with sub-atmospheric
conditions, a vacuum breaker andhydraulic pressure due to conden-sate will prevent stall and allowthe trap to drain the coil.Step 4. In many systems, the trapdoes not discharge freely toatmosphere and in our example,total back pressure on the trap is15 psig, drawn as horizontal dot-ted line (P2). Coil pressure equalsback pressure at the intersectionof (P2) with (P1/MT1) which whendropped vertically downward to(R1) occurs at 93% load. At lessthan this load, the required trapdifferential is eliminated, the sys-tem “stalls,” and the coil begins towaterlog. In our air heating coilthe air flows at a constant rateand extending the air tempera-ture intersection horizontally to(R2), stall occurs when the incom-ing air is 6°F or more.
The same procedure appliesto a heat exchanger although theexample temperature is not acommon one. If the stall chart
example represented a heatexchanger where the liquid was tobe heated through a constant tem-perature rise from 0 to 80°F, but ata flow rate that varies, stall wouldstill occur below 93% load. In thisinstance, if 100% load representsa 50 GPM exchanger, the systemwould stall when the demand was46.5 GPM (50 x .93) or less.
Draining Equipment Under“Stall” Conditions“System stall” is lack of positivedifferential across the steam trapand temperature controlledequipment will always be subjectto this problem when the trapmust operate against back pres-sure. Under these conditions, avacuum breaker is ineffectivebecause “stall” always occursabove atmospheric pressure.Even when steam is supplied at aconstant pressure or flow to“batch” type equipment, stall canoccur for some period of time onstartup when the steam condens-es quickly and the pressure dropsbelow the required differential.
What happens when the sys-tem stalls is that the effective coilarea (“UA” in the formula) drops asthe steam chamber floods andheat transfer is reduced until thecontrol valve responds to deliveran excessive supply of steam tothe coil. This results in a “huntingsystem” with fluctuating tempera-tures and hammering coils as therelatively cooler condensate alter-nately backs up, then at least someportion is forced through the trap.
The solution to all system stallproblems is to make condensatedrain by gravity. Atmospheric sys-tems tend to operate morepredictably and are generally eas-ier to control but major heatingequipment is usually not drainedinto an atmospheric returnbecause of the large amount ofenergy that is lost from the vent.In many process plants, ventingvapors of any type is discouragedand a “closed loop” system is notonly required but is less subject tooxygen corrosion problems.
SYSTEMDESIGN
Figure 46: Air Make-up Coil Stall Chart
100 90 80 70 60 50 40 30 20 10 0
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Draining Temperature Controlled Steam Equipment
35
Closed Loop DrainageSystemsTo make equipment drain bygravity against back pressure, thesteam trap must be replaced by aPressure Powered Pump™ orpump/trap combination installedin a closed loop system. In thisarrangement, the equipmentdoes not have a vacuum breakerbut is pressure equalized to drainby gravity, then isolated whilecondensate is pumped from thesystem. The basic hookup isshown in Fig. II-32 (page 99)where the equipment is constant-ly stalled and back pressurealways exceeds the control valvesupply pressure.
In many closed loop applica-tions, the pump alone is notsuitable because the steam sup-ply pressure can at times exceedthe back pressure (P1 is higher onthe “Stall Chart” than P2.) Theseapplications require the PressurePowered Pump™ to be fitted inseries with a Float andThermostatic trap (combinationpump-trap) to prevent steamblowthrough at loads above thestall point.
With pressurized returns andlarger coils, it is often economicalto fit a combination pump/trap toeach coil in a closed loop systemrather than the conventional grav-ity drain line acceptingcondensate from several trapsand delivering it to a commonpump. The pump/trap system isillustrated in Fig. II-35 (page 101)with the check valve fitted afterthe trap. This hookup assuresmaximum heat from the equip-ment and provides the additionaladvantages of no atmosphericventing, no vacuum breakers,therefore less oxygen contamina-tion and no electric pump seals toleak. Integral to the design of thissystem is the air vent for startup,the liquid reservoir for accumula-tion during discharge, andconsideration should also begiven to shutdown draining with aliquid expansion steam trap.
Sizing A CombinationPump/TrapThe Pressure-Powered Pump™
selected must have capacity tohandle the condensate load fromthe equipment at the % stall con-dition. Trap sizing is more criticaland should be a high capacity
Float and Thermostatic type sizednot for the equipment load, but tohandle the high flow rate duringthe brief pump discharge period.
The trap must be capable ofhandling the full system operatingpressure with a capacity of stallload at 1/4 psig. This size trap willallow the pump to operate at itsmaximum capacity.
Multiple Parallel Coils With ACommon Control ValveWhile group trapping should gen-erally be avoided, a system with asingle control valve supplyingsteam to identical parallel coilswithin the same air stream can bedrained to a single pump/trapcombination closed loop system.(See Fig. 47.) This hookuprequires that the pressure must befree to equalize into each coil. Noreduced coil connections can bepermitted and the common con-densate manifold must not onlypitch to the pump but be largeenough to allow opposing flow ofsteam to each coil while conden-sate drains to the pump/trap. Thebasic premise still applies, thatcoils which are fully air vented andfree to drain by gravity give maxi-mum heat output.
SYSTEMDESIGN
Figure 47Combination Pressure-Powered Pump/Traps in a Closed Loop Eliminate Waterlogging in Parallel Steam CoilsPreviously Trapped to a “Stalled” Level Control System
Steam Control Inlet
High PressureDrip Traps
To Drain
Level-ControlDrain Tank
Steam Control Inlet
SteamCoils
SteamCoils
ToCondensateReturn
Steam Control Inlet Steam ControlInlet
ToCondensateReturn
SteamCoils
SteamCoils
MotiveSteam
MotiveSteam
AirVent
AirVent
AirVent
AirVent
AirVent
AirVent
Pressure Powered Pump/Trap
Reservoir
Before After
Draining Temperature Controlled Steam Equipment
36
In many cases, a fluid is heatedby passing it through a series ofheat exchangers which are allprovided with steam through acommon control valve (Fig. 48).Multiple section air heater coils or“batteries” typify such applica-tions, as also the multi-roll dryersused in laundries. While the loadon the first heater is usuallyappreciably greater than the loadon later heater sections, the pro-portion of the total load whicheach section takes is often a mat-ter of “rule of thumb” or evenconjecture.
The temperature differencebetween the steam and the enter-ing cold fluid can be designated∆t1. Similarly, the temperature dif-ference between the steam andthe outlet heated fluid can be ∆t0.The ratio between ∆t1 and ∆t0 canbe calculated, and will always beless than one, see Fig. 49 (page37)
If the chart at Figure 50 isentered on the horizontal axis atthis ratio, a vertical can be takenupwards until the curve corre-sponding with the number ofheaters or coils in use is inter-sected. A horizontal from this
SYSTEMDESIGN
Absorption chillers are important sources of cooling nec-essary for many refinery processes. A typical example isthe need to cool products (using large heat exchangers)after the stripping process in an “alky” unit. Productsgoing to storage are generally maintained below 100°F.
Steam is used to drive the absorption process at lowpressure, typically below 15 psig. Condensate drainagebecomes a very real concern.
In this case, steam is supplied at 12 psig to the chillerthrough an automatic control valve. Condensate systembackpressure is a constant 6-7 psig, considering the 30 ft.uphill pipe-run to the vented condensate receiver. TheRefinery Contact Engineer recognized the potential forsystem stall (having previously used the PressurePowered Pump™ to overcome other similar problems).
SolutionTwo Pressure Powered Pumps™ were installed in paral-lel, along with necessary steam traps, air vents andstrainers . The Refinery supplied the reservoir and inter-connecting piping.
Benefits• Regardless of varying steam supply pressure, consid-
ering the throttling that naturally occurs through theautomatic control valve, thorough condensate drainageis assured and cooling efficiency is maintained.
• Installation cost was much lower with the PressurePowered Pumps™ over electric pumps that were alsobeing considered. Costly water and explosion proofcontrol panels were not required.
• Pump maintenance cost is also much lower throughelimination of the need for mechanical seals and pumpmotors.
Case in Action: Absorption Chiller, Condensate Drainage
Figure 48Multiple Coil Air Heater
point given the proportion of thetotal heater load which is carriedby the first section.
Multiplying this proportion bythe total load given the conden-sate rate in this section, andenables a trap with sufficientcapacity to be selected.
If it is required to accuratelydetermine the load in the second
section, estimate the temperatureat the outlet from the first section,and regard this as the inlet tem-perature for an assembly withone less section than before.Recalculate the ratio ts - to/ts - ti2,and re-enter the chart at thisvalue to find the proportion of theremaining load taken by the “first”of the remaining sections.
Multi-Coil Heaters
Steam Temp. ts
Air InletTemp. ti
Air OutletTemp. to
Multi-Coil Heaters
37
SYSTEMDESIGN
Figure 50Load on First Section of Multi-Coil Heater
Figure 49Temperature Distribution in Multi-Coil Heater
Paper Mills require a huge volume of air exchange. Thismeans that a great deal of air heating is necessary, partic-ularly during winter months. Air Make-Up systems are splitbetween two general applications:
a. Machine or Process Air Make-Up is supplied to t heimmediate area around the machine and, more specifi-cally, to certain areas within the machine for highertemperature heating (i.e. Pocket Ventilation or PV coils).
b. Mill Air Make-Up, which is distributed across the mill forHVAC comfort.
Either application may be accomplished with singlebanks of coils or double-preheat/reheat coils, dependingon heating requirements.
The mill experienced a chronic problem of frozen AirMake-Up coils, typically associated with condensate flood-ing and waterhammer. The 50/150 psig steam coilsballooned and ruptured routinely, creating costly mainte-nance headaches and safety hazards. Several coils wereremoved from service, requiring extensive repair.
SolutionMill Engineers, working with the local Spirax SarcoRepresentative, developed a long-range plan to redesignand retrofit the entire Air Make-Up System. Over the lasttwo years, approximately 20 Pressure PoweredPump™/float & thermostatic trap closed-loop packageshave been installed. The project will continue until theentire system is retrofitted. They have similarly retrofittedseveral shell and tube heat exchangers, improving waterheating efficiency.
Benefits• Energy savings are achieved through installation of
pressurized closed-loop packages. There is no loss toflash.
• Chemical savings are achieved because of the pressur-ized packages. Chemicals are not lost out the vent.
• Desired air heating efficiency has been achieved. Allretrofitted coils have operated properly and continuous-ly since installation. Flooding has been eliminated.
• Maintenance costs dropped dramatically with elimina-tion of condensate flooding, water-hammer andfreezing.
• Personnel safety has improved as steam/condensateleaks have been reduced.
Case in Action: Air Make-Up Coil Drainage
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
Ratio ∆to/∆tiP
rop
ort
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Lo
ad o
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0.9
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Three SectionFour SectionFive Section
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∆ti
ti2
∆to
Steam Trap Selection
38
Steam Trap SizingSteam main drip traps shall besized with a 2 times safety factorat full differential pressure. Inmost cases, they will be 3/4” sizewith low capacity orifice or small-er unless otherwise shown on thedrawings and they shall be locat-ed every 200 feet or less. Trapsfor steam tracing shall be 1/4" to1/2" size. They shall be locatedevery 100 feet or less. Radiatortraps shall be pipe size. Freezeprotection traps shall be 1/2" to3/4" size unless otherwise noted.
Traps for equipment drainageare sized with safety factors thatreflect the differences of theHVAC and Process industries,such as variations in actualhydraulic head and material con-struction of tube bundles. Asummary of these typical recom-mendations are as follows:HVAC Industry• Non-modulating control sys-
tems have traps selected witha 2 times factor at full pres-sure differential.
• Modulating control systemswith less than 30 psig inletpressure have traps selected
for full-load at 1/2 psi pres-sure differential, provide 18 to24" drip leg for condensate todrain freely to 0 psi gravityreturn. (With drip legs lessthan 18", consult a SpiraxSarco representative.)
• Modulating control systemswith greater than 30 psig inletpressure have traps selectedwith a 3 times factor at fullpressure differential for allpreheat coils, and a 2 timesfactor for others.
Process Industry• Non-modulating control sys-
tems have traps selected witha 2 times factor at full pres-sure differential.
• Modulating controls systemswith less than 30 psig inletpressure have traps selectedfor full load at 1/2 psi pres-sure differential, provide 18 to24" drip leg for condensate todrain freely to gravity returnat 0 psi. (With drip legs lessthan 18", consult a SpiraxSarco representative.)
• Modulating control systemshave traps selected with a 3times factor at full pressuredifferential.
SYSTEMDESIGN
A full discussion of steam trapfunctions are found in the com-panion Fluid System Designvolume, “STEAM UTILIZATION.”The material covers operation ofall types of traps, along with theneed for proper air venting andtrap selection. Traps are bestselected not just on supply pres-sure and load requirements, butafter reviewing the requirementsof the application compared totrap characteristics including dis-charge temperature, air ventingcapability, response to pressureand load change, and resistanceto dirt, corrosion, waterhammerand freezing conditions.Answering these questions leadsto the selection of the mostappropriate generic type of trapand the general recommenda-tions found in Table 11 reflect this.This Selection Guide covers mosttrap uses and the recommendedtype can be expected to give sat-isfactory performance.
Condensate removal was needed from 3 polyvinyl butyralextruders at a pressure of 240 psi. Application requiredthat a consistent temperature be maintained the length ofthe extruder to provide product quality in the melt. Therewere nine sections per extruder.
The customer had used various brands of traps andtrap styles to drain the extruders. Most recently they useda competitors bimetallic trap. They were experiencinginconsistent temperatures throughout the length of theextruder because the bimetallic traps subcooled the con-densate, which then backed up into the heat transfer area.They were also experiencing high maintenance costs inrelation to these traps.
SolutionFloat & Thermostatic steam traps were recommended fordraining the extruders. This would give them immediatecondensate removal; therefore maintaining a consistanttemperature throughout the length of the extruder, provid-ing better control over product melt. Also, uponrecommendation, strainers were installed before the trapsto help keep dirt out, and cut down on maintenance cost.
Benefits• Maintained consistent temperatures with existing equip-
ment because there is no condensate in the heattransfer area.
• There is less maintenance cost due to the strainersinstalled before the traps.
Case in Action: Polyvinyl Butyral Extruders
Steam Trap Selection
39
A QUICK GUIDE TO THE SIZING OF STEAM TRAPSNeed To Know:1. The steam pressure at the trap—after any pressure drop through
control valves or equipment.
2. THE LIFT, if any, after the trap.Rule of thumb: 2 ft. = 1 psi back pressure, approximately.
3. Any other possible sources of BACK PRESSURE in thecondensate return system.e.g.A) Condensate taken to a pressurized DA. tank.
B) Local back pressure due to discharges of numerous traps close together into small sized return.
4. QUANTITY of condensate to be handled. Obtained fromA) Measurement, B) Calculation of heat load (see page 24), and C) Manufacturer’s Data
5. SAFETY FACTOR—These factors depend upon particularapplications, typical examples being as follows:
General With Temp. ControlMains Drainage x2 —Storage Heaters x2 —Space Unit Heaters x2 x3Air Heating Coils x2 x3Submerged Coils (low level drain) x2 —Submerged Coils (siphon drain) x3 —Rotating Cylinders x3 —Tracing Lines x2 —Platen Presses x2 —
Rule of thumb: Use factor of 2 on everything except Temperature Controlled Air Heater Coils and Converters, and Siphon applications.
How To UseThe difference between the steam pressure at the trap, and the totalback pressure, including that due to any lift after the trap, is theDIFFERENTIAL PRESSURE. The quantity of condensate should bemultiplied by the appropriate factor, to produce SIZING LOAD. Thetrap may now be selected using the DIFFERENTIAL PRESSURE andthe SIZING LOAD.
ExampleA trap is required to drain 22 lb/h of condensate from a 4" insulatedsteam main, which is supplying steam at 100 PSIG. There will be a liftafter the trap of 20 ft.
Supply Pressure = 100 psigLift = 20 ft = 10 psi approx.
ThereforeDifferential Pressure = 100 – 10 = 90 psi
Quantity = 22 lb/hrMains Drainage Factor = 2
Therefore Sizing Load = 44 lb/hr
A small reduced capacity Thermo-Dynamic® steam trap will easilyhandle the 44 lb/h sizing load at a differential pressure of 90 psi.
SYSTEMDESIGN
Steam TrapSelection SoftwareSelecting the best type and sizesteam trap is easier today for sys-tem designers who use MS DOScomputer software programs.The Spirax Sarco “STEAMNEEDS ANALYSIS PROGRAM”is available on request and goesa step further. SNAP not only rec-ommends and sizes the trap frominput conditions, but also speci-fies condensate return pumps,other necessary auxiliary equip-ment, and warns of systemproblems that may be encoun-tered. The SNAP program isuser-friendly, menu-driven soft-ware that accurately calculatesthe condensate load for a widerange of drip, tracing and processapplications (described both bycommon name and genericdescription.) Significant is the factthat a SNAP user has the choiceof selecting either a recommend-ed type of trap or a different typethat may be preferred for any rea-son. For modulating steamsystems, the air temperature andpercentage of load at which “stall”occurs is predicted and, whenrequested, the combinationpump/trap solution is correctlysized and specified. For all selec-tions, a formal specification sheetmay be printed which containsadditional information.
As the USA’s leading provider of steam system solutions, Spirax Sarco recognizes that no two steam trappingsystems are identical. Because of the wide array of steam trap applications with inherently different characteristics,choosing the correct steam trap for optimum performance is difficult. Waterhammer, superheat, corrosive conden-sate, or other damaging operating characteristics dramatically affect performance of a steam trap. With over 80years of experience in steam technology, Spirax Sarco is committed to helping it’s customers design, operate andmaintain an efficient steam system. You have our word on it!
Steam Trap Selection Guide
40
SYSTEMDESIGN
1st Choice 2nd ChoiceFloat & Thermo- Balanced Liquid Inverted Float & Thermo- Balanced Liquid Inverted
Application Thermostatic Dynamic® Pressure Bimetallic Expansion Bucket Thermostatic Dynamic® Pressure Bimetallic Expansion Bucket
Steam Mains to 30 psig ✓ ✓
30-400 psig ✓ ✓
to 600 psig ✓ ✓
to 900 psig ✓ ✓
to 2000 psig ✓ ✓
with Superheat ✓ ✓
Separators ✓ ✓
Steam Tracers Critical ✓ ✓
Non-Critical ✓ ✓
Heating Equipment
Shell & Tube Heat Exchangers ✓ ✓
Heating Coils ✓ ✓
Unit Heaters ✓ ✓
Plate & Frame Heat Exchangers ✓ ✓
Radiators ✓
General Process Equipment
to 30 psig ✓ ✓
to 200 psig ✓ ✓
to 465 psig ✓ ✓
to 600 psig ✓
to 900 psig ✓
to 2000 psig ✓
Hospital Equipment
Autoclaves ✓ ✓
Sterilizers ✓ ✓
Fuel Oil Heating
Bulk Storage Tanks ✓ ✓
Line Heaters ✓
Tanks & Vats
Bulk Storage Tanks ✓ ✓
Process Vats ✓ ✓
Vulcanizers ✓ ✓
Evaporators ✓ ✓
Reboilers ✓ ✓
Rotating Cylinders ✓
Freeze Protection ✓
Table 11: Steam Trap Selection Guide
Flash Steam
41
The Formation of Flash SteamWhen hot condensate underpressure is released to a lowerpressure, its temperature mustvery quickly drop to the boilingpoint for the lower pressure asshown in the steam tables. Thesurplus heat is utilized by thecondensate as latent heat caus-ing some of it to re-evaporate intosteam. Commonly referred to as“flash steam”, it is in fact perfect-ly good useable steam even atlow pressure.
Proportion Of Flash SteamReleasedThe amount of flash steam whicheach pound of condensate willrelease may be calculated readi-ly. Subtracting the sensible heatof the condensate at the lowerpressure from that of the conden-sate passing through the trapswill give the amount of heat avail-able from each pound to provideLatent Heat of Vaporization.Dividing this amount by the actu-al Latent Heat per pound at theLower Pressure will give the pro-portion of the condensate whichwill flash off. Multiplying by thetotal quantity of condensate beingconsidered gives the weight ofLow Pressure Steam available.
To simplify this procedure wecan use Table 12 to read off thepercentage of flash steam pro-duced by this pressure drop. Anexample would be if we had 100PSIG saturated steam/conden-sate being discharged from asteam trap to an atmospheric,gravity flow condensate returnsystem (0 psig), the flash per-centage of the condensate wouldbe 13.3% of the volume dis-charged.
Conversely, if we had 15 psigsaturated steam discharging tothe same (0 psig) atmosphericgravity flow return system, thepercentage of flash steam wouldbe only 4% by volume. Theseexamples clearly show that theamount of flash released
depends upon the differencebetween the pressures upstreamand downstream of the trap andthe corresponding temperaturesof those pressures in saturatedsteam. The higher the initial pres-sure and the lower the flashrecovery pressure, the greaterthe quantity of flash steam pro-duced.
It must be noted here that thechart is based upon saturatedsteam pressure/temperature con-ditions at the trap inlet, and thatthe condensate is discharged asrapidly as it appears at the trap.Steam traps that subcool the con-densate, such as balancedpressure thermostatic andbimetallic traps, hold condensateback in the system allowing it togive up sensible heat energy andcausing it to cool below the satu-rated steam temperature for thatpressure. Under those circum-stances, we must calculate fromthe formula above the percentageof flash steam produced, but theamount of subcooling (the con-densate temperature) must beknown before calculating.
SYSTEMDESIGN
Table 12: Percent FlashSteam
Pressure Atmosphere Flash Tank Pressurepsig 0 2 5 10 15 20 30 40 60 80 100
5 1.7 1.0 010 2.9 2.2 1.4 015 4.0 3.2 2.4 1.1 020 4.9 4.2 3.4 2.1 1.1 030 6.5 5.8 5.0 3.8 2.6 1.7 040 7.8 7.1 6.4 5.1 4.0 3.1 1.3 060 10.0 9.3 8.6 7.3 6.3 5.4 3.6 2.2 080 11.7 11.1 10.3 9.0 8.1 7.1 5.5 4.0 1.9 0
100 13.3 12.6 11.8 10.6 9.7 8.8 7.0 5.7 3.5 1.7 0125 14.8 14.2 13.4 12.2 11.3 10.3 8.6 7.4 5.2 3.4 1.8160 16.8 16.2 15.4 14.1 13.2 12.4 10.6 9.5 7.4 5.6 4.0200 18.6 18.0 17.3 16.1 15.2 14.3 12.8 11.5 9.3 7.5 5.9250 20.6 20.0 19.3 18.1 17.2 16.3 14.7 13.6 11.2 9.8 8.2300 22.7 21.8 21.1 19.9 19.0 18.2 16.7 15.4 13.4 11.8 10.1350 24.0 23.3 22.6 21.6 20.5 19.8 18.3 17.2 15.1 13.5 11.9400 25.3 24.7 24.0 22.9 22.0 21.1 19.7 18.5 16.5 15.0 13.4
Percent flash for various initial steam pressures and flash tank pressures.
Thus, if for example, 2000lb/h of condensate from a sourceat 100 psi is flashed to 10 psi, wecan say:
Sensible Heat at 100 psi = 309 Btu/lbSensible Heat at 10 psi = 208 Btu/lb
Heat Available for Flashing = 101 Btu/lbLatent Heat at 10 psi = 952 Btu/lb
Proportion Evaporated = 101 .–. 952 = 0.106 or 10.6%
Flash Steam Available = 0.106 x 2000 lb/h= 212 lb/h
Flash Steam
42
Flash Steam UtilizationIn an efficient and economicalsteam system, this so calledFlash Steam will be utilized, onany load which will make use oflow pressure steam. Sometimesit can be simply piped into a lowpressure distribution main forgeneral use. The ideal is to havea greater demand for LowPressure steam, at all times, thanavailable supply of flash steam.Only as a last resort should flashsteam be vented to atmosphereand lost.
If the flash steam is to berecovered and utilized, it has tobe separated from the conden-sate. This is best achieved bypassing the mixture of flashsteam and condensate throughwhat is know as a “flash tank” or“flash vessel”. A typical arrange-ment is shown in Fig. II-76 (page120). The size of the vessel hasto be designed to allow for areduced velocity so that the sep-aration of the flash steam andcondensate can be accomplishedadequately, so as not to have car-ryover of condensate out into theflash steam recovery system.This target velocity is ten feet persecond per ASHRAE standardsto ensure proper separation. Thecondensate drops to the bottomof the flash tank where it isremoved by a float and thermo-static steam trap. The flash steamoutlet connection is sized so thatthe flash steam velocity throughthe outlet is approximately 50ft./sec. The condensate inlet isalso sized for 50 ft./sec. flashvelocity.
A number of basic require-ments and considerations have tobe met before flash steam recov-ery is a viable and economicalproposition:1. It is first essential to have a
sufficient supply of conden-sate, from loads at sufficientlyhigher pressures, to ensurethat enough flash steam willbe released to make recov-ery economically effective.
The steam traps, and theequipment from which theyare draining condensate,must be able to function sat-isfactorily while accepting thenew back pressure applied tothem by the flash recoverysystem. Particular care isneeded when attempting torecover flash steam fromcondensate which is leavingequipment controlled by amodulating temperature con-trol valve. At less than fullloads, the steam space pres-sure will be lowered by theaction of the temperaturecontrol valve. If the steamspace pressure approachesor even falls below the flashsteam vessel pressure, con-densate drainage from thesteam space becomesimpractical by a steam trapalone, and the equipmentbecomes “stalled” and waterlogging will most definitelyoccur.
2. The second requirement is asuitable use for low pressureflash steam. Ideally, low pres-sure load(s) requires at alltimes a supply of steamwhich either equals orexceeds the available flashsteam supply. The deficit canthen be made up through apressure reducing valve set.If the supply of flash steamexceeds the demand for it,the surplus may have to bevented to waste through abackpressure control valve(see Fig. II-77, page 120).Thus, it is possible to utilizethe flash steam from processcondensate on a space heat-ing installation - but thesavings will only be achievedduring the heating season.When heating is not required,the recovery systembecomes ineffective.Whenever possible, the bet-ter arrangement is to useflash steam from processcondensate to supply
process loads, and that fromheating condensate to supplyheating loads. Supply anddemand are then more likelyto remain “in step”. When allelse fails, in many facilitiesthere is always a need for hotwater, especially in the boilerhouse. This can be suppliedvia a heat exchanger and theuse of flash steam.
3. It is also preferable to selectan application for the flashsteam which is reasonablyclose in proximity to the highpressure condensate source.Piping for low pressuresteam is inevitably of largerdiameter. This makes itsomewhat costly to install.Furthermore, the heat lossfrom large diameter pipesreduces the benefits obtainedfrom flash steam recoveryand in the worst cases couldoutweigh them.Flash steam recovery is sim-
plest when being recovered froma single piece of equipment thatcondenses a large amount ofsteam, such as a large steam towater converter of a large air han-dling coil bank, but we cannotforget that flash steam recoverysystems by design will apply abackpressure to the equipmentbeing utilized as the flash steamsource.
How To Size Flash TanksAnd Vent LinesWhether a flash tank is atmos-pheric or pressurized for flashrecovery, the procedure for deter-mining its size is the same. Themost important dimension is thediameter. It must be large enoughto provide adequate separation ofthe flash and condensate to mini-mize condensate carryover.
SYSTEMDESIGN
Flash Steam
43
ExampleSize a 20 psig flash recovery ves-sel utilizing condensate from a160 psig steam trap discharging3000 lb/h.1. Determine percent flash
steam produced using Table12. With a steam pressure of160 psig and a flash tankpressure of 20 psig, read avalue of 12.4%.
2. Next, multiply the condensateload by the percent flash fromStep #1 to determine the
flowrate, of flash steam pro-duced. 3,000 lb/h x .124 =372 lb/h.
3. Using the calculated flashsteam quantity of 372 lb/henter Fig. 51 at “A” and movehorizontally to the right to theflash tank pressure of 20 psig“B”. Rise vertically to theflash tank diameter line (600ft/min) at “D”. Read tankdiameter of 5”. If schedule 80pipe is to be installed, thetable within the body of the
chart can be used to deter-mine whether the velocity willexceed the recommendedlimit of 600 ft/min.
4. From point “D” continue torise vertically to “E” to deter-mine the size of vent pipe togive a velocity between 3000and 4000 ft/min. In this case2” schedule 40 pipe. Asbefore, use the table withinthe body of chart for schedule80 pipe.
SYSTEMDESIGN
6000
3000
4000
2000
1000
600
100
66
50
33
50,000
30,000
20,000
10,000
8000
20
30
40
5060
80
100
200
300
500
8001000
2000
3000
5000
Fla
sh S
team
Flo
wra
te (
lb/h
)
Velocity(ft/sec)
Velocity(ft/min)
Pressure in
condensate line or
flash tank (psig)
Pipe Size (schedule 40)
A
D
E
C
RecommendedService
Condensate ReturnLine Sizing
Vent Pipe Sizing
Flash TankDiameter Sizing
10
17
28"30"24"
26"20"
18"16"
14"12" 10" 8" 6" 5" 4" 3"
2-1/2"2"
1-1/2"1-1/4"
1" 3/4"1/2"
B
1008060403020
1050
1008060403020
1050
1008060403020
1050
Multiply chart velocityby factor belowto get velocity
in schedule 80 pipe
Pipe Size1/2"3/4" & 1"1-1/4" & 1-1/2"2" & 3"4" to 24"26" to 30"
Factor1.301.231.151.121.11.0
10
Figure 51: Condensate Line, Flash Tank, and Vent Line Sizing
Flash Steam
44
SYSTEMDESIGN
Condensateinlet
Flash Steamoutlet or vent pipe
DiameterLength
Condensateoutlet
Length = 2 x diameter or24" minimum
For proper installation of flash vessels, controls and traps refer toFigures II-76, 77, 78, 79, 80, 81, 82, 83 (starting on page 120)
HorizontalFlash Vessel
Vertical FlashVessel
Figure 52: Flash Vessel Configurations
Diameter
35% ofheight
Condensateinlet
Condensateoutlet
Height = 3 x Diameter or36" minimum
Flash steam outletor vent pipe
The sour water condenser-reboiler is an important elementin a refinery sulfur unit. Though the configuration/designwill vary with the specific process used, the purpose andpriority remain the same. Process water contaminated withammonia and hydrogen sulfide gas (H2S) is stripped ofthose compounds for reuse. The remaining stream of con-taminants goes to waste treatment. The process dependson accurate temperature control of the steam heated con-denser-reboiler.
40 psig steam is supplied through a modulating con-trol valve. Condensate is lifted 15 feet from the outlet at thebottom of the vertical condenser-reboiler to the overheadcondensate receiver tank, which is maintained at 20 psig.Process load fluctuations and resultant turndown on themodulating steam control valve would have created aSTALL situation, unacceptable process temperature con-trol and reduced throughput.
SolutionA 3" x 2" PPF with 2-1/2" FTB 125 pump/trap combinationwas designed into the new project as was a VS 204 airvent. The installation was immediately successful.
Benefits• With faster start-up, it came up to temperature faster
than any other comparable unit, to date, at the refinery.This improves productivity.
• The feed rate is higher than designed because the unitis able to operate efficiently at any degree of turndown.
• Installation cost is several times less costly for thepump/trap combo than traditional level control systemthat would otherwise have been used.
• Maintenance cost is lower, through elimination of elec-tric/pneumatic controls and electric pumps used in atraditional level control system.
Case in Action: Sour Water Condenser-Reboiler Temperature Control
Flash Vessel ConfigurationsFlash vessels can be either horizontal or vertical. For flash steam recovery (pressurized receiver) the verticalstyle is preferred because of its ability to provide better separation of steam and water.
Condensate Recovery Systems
45
The importance of effective con-densate removal from steamspaces has been stressedthroughout this course. If maxi-mum steam system efficiency isto be achieved, the best type ofsteam trap must be fitted in themost suitable position for theapplication in question, the flashsteam should be utilized, and themaximum amount of condensateshould be recovered.
There are a number of rea-sons why condensate should notbe allowed to discharge to drain.The most important considerationis the valuable heat which it con-tains even after flash steam hasbeen recovered. It is possible touse condensate as hot processwater but the best arrangement isto return it to the boiler house,where it can be re-used as boilerfeed water without further treat-ment, saving preheating fuel, rawwater and the chemicals neededfor boiler feed treatment. Thesesavings will be even greater incases where effluent chargeshave to be paid for the dischargeof valuable hot condensate downthe drain.
Condensate recovery sav-ings can add up to 20 to 25% ofthe plant’s steam generatingcosts. One justifiable reason fornot returning condensate is therisk of contamination. Perforatedcoils in process vessels and heatexchangers do exist and thecross contamination of conden-sate and process fluids is alwaysa danger. If there is any possibili-ty that the condensate iscontaminated, it must not bereturned to the boiler. Theseproblems have been lessened bythe application of sensing sys-tems monitoring the quality ofcondensate in different holdingareas of a plant to determine con-densate quality and providing ameans to re-route the conden-sate if contaminated.
Condensate Line SizingCondensate recovery systemsdivide naturally into three sec-tions, each section requiringdifferent design considerations.a. Drain Lines to the traps carry
pressurized high temperaturehot water that moves by grav-ity.
b. Trap discharge lines thatcarry a two-phase mixture offlash steam and condensate.
c. Pumped return systems uti-lizing electric or non-electricpumps.
Drain Lines To TrapsIn the first section, the conden-sate has to flow from thecondensing surface to the steamtrap. In most cases this meansthat gravity is relied on to induceflow, since the heat exchangersteam space and the traps are atthe same pressure. The linesbetween the drainage points andthe traps can be laid with a slightfall, say 1” in 10 feet, and Table13 shows the water carryingcapacities of the pipes with sucha gradient. It is important to allowfor the passage of incondensiblesto the trap, and for the extra waterto be carried at cold starts. Inmost cases, it is sufficient to sizethese pipes on twice the full run-ning load.
Trap Discharge LinesAt the outlet of steam traps, thecondensate return lines mustcarry condensate, non-condensi-ble gases and flash steamreleased from the condensate.Where possible, these linesshould drain by gravity to the con-densate receiver, whether this bea flash recovery vessel or thevented receiver of a pump. Whensizing return lines, two importantpractical points must be consid-ered.
First, one pound of steamhas a specific volume of 26.8cubic feet at atmospheric pres-sure. It also contains 970 BTU’sof latent heat energy. This meansthat if a trap discharges 100pounds per hour of condensatefrom 100 psig to atmosphere, theweight of flash steam releasedwill be 13.3 pounds per hour, hav-ing a total volume of 356.4 cubicfeet. It will also have 12,901BTU’s of latent heat energy. Thiswill appear to be a very largequantity of steam and may welllead to the erroneous conclusionthat the trap is passing live steam(failed open).
Another factor to be consid-ered is that we have just released13.3 pounds of water to theatmosphere that should havegone back to the boiler house forrecycling as boiler feed water.Since we just wasted it, we nowhave to supply 13.3 pounds offresh city water that has beensoftened, chemically treated andpreheated to the feedwater sys-tem’s temperature before puttingthis new water back into the boil-er.
Secondly, the actual forma-tion of flash steam takes placewithin and downstream of thesteam trap orifice where pressuredrop occurs. From this pointonward, the condensate returnsystem must be capable of carry-ing this flash steam, as well ascondensate. Unfortunately, in thepast, condensate return lines
SYSTEMDESIGN
Table 13: Condensate, lb/hSteel Approximate Frictional ResistancePipe in inches Wg per 100 ft of TravelSize 1 5 7 101/2" 100 240 290 3503/4" 230 560 680 8201" 440 1070 1200 155011/4" 950 2300 2700 330011/2" 1400 3500 4200 50002" 2800 6800 8100 990021/2" 5700 13800 16500 200003" 9000 21500 25800 310004" 18600 44000 52000 63400
Condensate Recovery Systems
46
have been sized using water vol-ume only and did not include theflash steam volume that is pre-sent.
The specific volume of waterat 0 psig is .017 cubic feet perpound, compared to 26.8 cubicfeet per pound for flash steam atthe same pressure. Sizing of con-densate return lines from trapdischarges based totally on wateris a gross error and causes linesto be drastically undersized forthe flash steam. This causes con-densate lines to becomepressurized, not atmospheric,which in turn causes a backpres-sure to be applied to the trap’sdischarge which can causeequipment failure and flooding.
This undersizing explainswhy the majority of 0 psi atmos-pheric condensate returnsystems in the United States donot operate at 0 psig. To take thisthought one step further for thosepeople who perform temperaturetests on steam traps to determineif the trap has failed, the instantwe cause a positive pressure todevelop in the condensate returnsystem by flash steam, the con-densate return line now mustfollow the pressure/temperaturerelationship of saturated steam.So, trap testing by temperatureidentifies only that we have areturn system at a certain tem-perature above 212°F (0 psig)and we can then determine bythat temperature the systempressure at which it is operating.Elevated condensate return tem-peratures do not necessarilymean a trap has failed.
When sizing condensatereturn lines, the volume of theflash steam must be given dueconsideration. The chart at Fig.51 (page 43) allows the lines tobe sized as flash steam lines—since the volume of thecondensate is so much less thanthat of the steam released.
Draining condensate from
traps serving loads at differingpressures to a common conden-sate return line is a conceptwhich many find difficult. It isoften assumed that the HP “highpressure” condensate will pre-vent the “low pressure”condensate from passing throughthe LP traps and give rise towaterlogging of the LP system.
However, the terms HP andLP can only apply to the condi-tions on the upstream side of theseats in the traps. At the down-stream or outlet side of the traps,the pressure must be the com-mon pressure in the return line.This return line pressure will bethe sum of at least three compo-nents:1. The pressure at the end of
the return line, either atmos-pheric or of the vessel intowhich the line discharges.
2. The hydrostatic head neededto lift the condensate up anyrisers in the line.
3. The pressure drop needed tocarry the condensate andany flash steam along theline.Item 3 is the only one likely to
give rise to any problems if con-densate from sources at differentpressures enters a common line.The return should be sufficientlylarge to carry all the liquid con-densate and the varying amountsof flash steam associated with it,without requiring excessive linevelocity and excessive pressuredrop. If this is accepted, the totalreturn line cross sectional areawill be the same, whether a singleline is used, or if two or more linesare fitted, with each taking thecondensate from a single pres-sure source.
The return could becomeundersized, requiring a high pres-sure at the trap discharges andrestricting or preventing dis-charge from the LP traps, if it isforgotten that the pipe has to
carry flash steam as well as waterand that flash steam is releasedin appreciable quantity from HPcondensate.
While the percentage, byweight, of flash steam may berather low, its overall volume incomparison to the liquid is verylarge. By determining the quantityof flash steam and sizing thereturn line for velocities between4,000 and 6,000 ft/min, the two-phase flow within the pipe can beaccommodated. The informationrequired for sizing is the conden-sate load in lb/h, inlet pressure tosteam trap(s) in psig and returnline system pressure.Example:Size a condensate return linefrom a 160 psig steam trap dis-charging to 20 psig. flash tank.Load is 3,000 lb/h.1. Determine percent flash
steam produced using Table12 (page 41). With a steampressure of 160 psig and aflash tank pressure of 20 psigread a value of 12.4%.
2. Next, multiply the condensateload by the percent flash fromstep #1 to determine theflowrate, of flash steam pro-duced.3,000 lb/h x .124 = 372 lb/h.
3. Enter Fig. 51 (page 43) at theflash steam flowrate of 372lb/h at “A” and move horizon-tally to the right to the flashtank pressure of 20 psig “B”.Rise vertically to choose acondensate return line sizewhich will give a velocitybetween 4,000 and 6,000ft/min, “C”. In this example,an 1-1/2” schedule 40 pipewith a velocity of approxi-mately 5,000 ft/min. Ifschedule 80 pipe is to beused, refer to table withinbody of chart. Multiply thevelocity by the factor to deter-mine whether the velocity iswithin acceptable limits.
SYSTEMDESIGN
Condensate Recovery Systems
47
Pumped Return LinesFinally, the condensate is oftenpumped from the receiver to theboiler plant. These pumped con-densate lines carry only water,and rather higher water velocitiescan often be used so as to mini-mize pipe sizes. The extra frictionlosses entailed must not increaseback pressures to the point wherethe pump capacity is affected.Table 35 (page 77) can be usedto help estimate the frictionalresistance presented by thepipes. Commonly, velocities inpumped returns should be limitedto 6-8 ft./sec.
Electric pumps are commonlyinstalled with pumping capabilityof 2-1/2 or 3 times the rate atwhich condensate reaches thereceiver. This increased instanta-neous flow rate must be kept inmind when sizing the deliverylines. Similar considerationsapply when steam poweredpumps are used, or appropriatesteps taken to help attain con-stant flow along as much aspossible of the system.
Where long delivery lines areused, the water flowing along thepipe as the pump dischargesattains a considerable momen-tum. At the end of the dischargecycle when the pump stops, thewater tends to keep moving alongthe pipe and may pull air or steaminto the delivery pipe through thepump outlet check valve. Whenthis bubble of steam reaches acooler zone and condenses, thewater in the pipe is pulled backtowards the pump. As thereversed flow reaches and closesthe check valve, waterhammeroften results. This problem isgreatly reduced by adding a sec-ond check valve in the deliveryline some 15 or 20 ft. from thepump. If the line lifts to a highlevel as soon as it leaves thepump, then adding a generouslysized vacuum breaker at the top
of the riser is often an extra help.However, it may be necessary toprovide means of venting fromthe pipe at appropriate points, theair which enters through the vac-uum breaker. See Figures II-71and II-72 (page 118).
The practice of connectingadditional trap discharge linesinto the pumped main is to beavoided whenever possible. Theflash steam which is releasedfrom this extra condensate leadsto thermal shock creating a bang-ing noise within the pipingcommonly associated with water-hammer. The traps shoulddischarge into a separate gravity
line which carries the condensateto the receiver of the pump. If thisis impossible, a second bestalternative may be to pipe thetrap discharge through a spargeor diffuser inside the pumpedreturn line.
The trap most suitable for thisapplication would be the Floatand Thermostatic type due to itscontinuous discharge. This isvery much a compromise and willnot always avoid the noise (seeFig. 53 and 53A) although it willreduce the severity.
SYSTEMDESIGN
Figure 53Discharge of Steam Trap into Pumped (flooded) Return Line usingSparge Pipe.
CondensateReturn
Dischargefrom Trap
Figure 53ADischarge of Steam Trap into Pumped (flooded) Return Lineusing a Trap Diffuser.
Spira-tecLoss Detector
Thermo-Dynamic
Steam Trapwith Integral
Strainer
Trap Diffuser
Condensate Pumping
48
In nearly all steam-using plants,condensate must be pumpedfrom the location where it isformed back to the boilerhouse,or in those cases where gravitydrainage to the boilerhouse ispractical, the condensate must belifted into a boiler feed tank ordeaerator. Even where deaera-tors are at low level, they usuallyoperate at a pressure a few psiabove atmospheric and again, apump is needed to lift condensatefrom atmospheric pressure todeaerator tank pressure.
Electric CondensateReturn PumpsWhen using electric pumps to liftthe condensate, packaged unitscomprising a receiver tank (usu-ally vented to atmosphere) andone or more motorized pumpsare commonly used. It is impor-tant with these units to make surethat the maximum condensatetemperature specified by themanufacturer is not exceeded,and the pump has sufficientcapacity to handle the load.Condensate temperature usuallypresents no problem with returnsfrom low pressure heating sys-tems. There, the condensate isoften below 212°F as it passesthrough the traps, and a little fur-ther subcooling in the gravityreturn lines and in the pumpreceiver itself means that there islittle difficulty in meeting the max-imum temperature limitation. SeeFig. II-74 (page 119).
On high pressure systems,the gravity return lines often con-tain condensate at just above212°F, together with some flashsteam. The cooling effect of thepiping is limited to condensing alittle of the flash steam, with theremainder passing through thevent at the pump receiver. Thewater must remain in the receiverfor an appreciable time if it is tocool sufficiently, or the pump dis-charge may have to be throttleddown to reduce the pump’s capac-ity if cavitation is to be avoided.See Fig. II-75 (page 119).
The absolute pressure at theinlet to the pump is usually theatmospheric pressure in thereceiver, plus the static head fromthe water surface to the pumpinlet, minus the friction lossthrough pipes, valves and fittingsbetween the receiver and thepump. If this absolute pressureexceeds the vapor pressure ofwater at the temperature at whichit enters the pump, then a NetPositive Suction Head exists.Providing this NPSH is above thevalue specified by the pump man-ufacturer, the water does notbegin to boil as it enters the pumpsuction, and cavitation is avoided.If the water entering the pump isat high temperature, its vaporpressure is increased and agreater hydrostatic head over thepump suction is needed to ensurethat the necessary NPSH isobtained.
If the water does begin to boilin the pump suction, the bubblesof steam are carried with thewater to a high pressure zone inthe pump. The bubbles thenimplode with hammer-like blows,eroding the pump and eventuallydestroying it. The phenomenon iscalled cavitation and is readilyrecognized by its typical rattle-likenoise, which usually diminishesas a valve at the pump outlet isclosed down.
However, since in mostcases pumps are supplied cou-pled to receivers and the static
head above the pump inlet isalready fixed by the pump manu-facturer, it is only necessary toensure that the pump set has suf-ficient capacity at the watertemperature expected at thepump. Pump manufacturers usu-ally have a set of capacity curvesfor the pump when handlingwater at different temperaturesand these should be consulted.
Where steam systems oper-ate at higher pressures thanthose used in LP space heatingsystems, as in process work, con-densate temperatures are often212°F, or more where positivepressures exist in return lines.Electric pumps are then usedonly if their capacity is downratedby partial closure of a valve at theoutlet; by using a receiver mount-ed well above the pump to ensuresufficient NPSH; or by subcoolingthe condensate through a heatexchanger of some type.
Pressure PoweredCondensate PumpAll these difficulties are avoidedby the use of non-electric con-densate pumps, such as thePressure Powered Pump™. ThePressure Powered Pump™ isessentially an alternating receiverwhich can be pressurized, usingsteam, air or other gas. The gaspressure displaces the conden-sate (which can be at anytemperature up to and includingboiling point) through a check
SYSTEMDESIGN
The PUMP NPSH in any given application can readily be estimatedfrom:
NPSH = hsv = 144 (Pa - Pvp) + hs - hfW
Where:Pa = Absolute pressure in
receiver supplying pump,in psi (that is at atmos-pheric pressure in thecase of a vented receiver).
Pvp= Absolute pressure ofcondensate at the liquidtemperature, in psi.
hs = Total suction head in feet.(Positive for a head abovethe pump or negative for alift to the pump)
hf = Friction loss in suction piping.W = Density of water in pounds
per cubic foot at theappropriate temperature.
Condensate Pumping
49
valve at the outlet of the pumpbody. At the end of the dischargestroke, an internal mechanismchanges over, closing the pres-surizing inlet valve and openingan exhaust valve. The pressuriz-ing gas is then vented toatmosphere, or to the space fromwhich the condensate is beingdrained. When the pressures areequalized, condensate can flowby gravity into the pump body torefill it and complete the cycle.
As the pump fills by gravityonly, there can be no cavitationand this pump readily handlesboiling water or other liquids com-patible with its materials ofconstruction.
The capacity of the pumpdepends on the filling head avail-able, the size of the condensateconnections, the pressure of theoperating steam or gas, and thetotal head through which the con-densate is lifted. This will includethe net difference in elevationbetween the pump and the finaldischarge point; any pressure dif-ference between the pumpreceiver and final receiver; frictionin the connecting pipework, andthe force necessary to acceleratethe condensate from rest in thepump body up to velocity in thedischarge pipe. Tables listingcapacities under varying condi-tions are provided in the catalogbulletins.
Piping RequirementsDepending upon the application,the Pressure Powered Pump™
body is piped so that it is ventedto atmosphere or, in a closed sys-tem, is pressure equalized backto the space that it drains. Thisallows condensate to enter thepump but during the short dis-charge stroke, the inlet checkvalve is closed and condensateaccumulates in the inlet piping. Toeliminate the possibility of con-densate backing up into thesteam space, reservoir pipingmust be provided above thepump with volume as specified in
the catalog. A closed systemrequires only a liquid reservoir. Inopen systems, the vented receiv-er serves this purpose as it isalways larger in order to also sep-arate the flash steam released.
Vented SystemsCondensate from low pressureheating systems may be pipeddirectly to a small size PressurePowered Pump™ only when 50lb/h or less of flash steam mustvent through the pump body. Thisdoes not eliminate the require-ment that there must be enoughpiping to store condensate duringthe brief discharge cycle. In manylow pressure systems, the reser-voir may be a section of largerhorizontal pipe which is vented toeliminate flash steam. In higherpressure, high load systems, thelarger quantity of flash releasedrequires a vented receiver withpiping adequate to permit com-plete separation. To preventcarryover of condensate from the
vent line, the receiver should besized to reduce flow velocity toabout 10 FPS.
Closed Loop SystemsIt is often advisable where largercondensate loads are being han-dled to dedicate a PressurePowered Pump™ to drain a singlepiece of equipment. The pumpexhaust line can then be directlyconnected to the steam space ofa heat exchanger or, preferablywith air heating coils, to the reser-voir. This allows condensate todrain freely to the pump inlet andthrough a steam trap at the pumpoutlet. Only liquid is contained inthe reservoir of a closed loop sys-tem. Fig.II-32 (page 99) illustrateshow the Pressure-Powered pumpfunctions as a pumping trap, anduse Fig. II-35 (page 101) whenthe steam supply may sometimesbe greater than the return pres-sure and a combinationpump/trap is required.
SYSTEMDESIGN
Figure 54Venting of Pump Exhaust and Inlet Receiver Pipe in aLow Pressure System
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa aaaaaaaaaaaaaaaaaaaaaaaaaaaCondensateReturn
SteamSupply
PressurePowered
Pump
Vented Receiver
Vent
Clean Steam
50
Clean SteamThe term “Clean Steam” cancover a wide range of steamqualities, depending on the pro-duction method used and thequality of the raw water.
The term “Clean Steam” issomething of a misnomer and iscommonly used as a blanketdescription to cover the threebasic types - filtered steam, cleansteam and pure steam.a) Filtered steam is produced by
filtering plant steam using ahigh efficiency filter. A typicalspecification would call for
the removal of all particlesgreater than 2.8 microns,including solids and liquiddroplets (Fig. 55).
b) Clean steam is raised in asteam generator or takenfrom an outlet on a multi-effect still, and is oftenproduced from deionized ordistilled water. A simpliffiedgenerator and distributionsystem is shown in Fig. 56.
c) Pure steam is very similar toclean steam, but is alwaysproduced from distilled,deionized or pyrogen-free
water, and is normallydefined as “uncondensedwater for injection (WFI)”.Often, the generic term “clean
steam” is used to describe any ofthe three different types outlinedabove. It is therefore very impor-tant to know which is being usedfor any application, as the charac-teristics and system requirementsfor each can differ greatly. Notethat in the following text, theexpression “clean” steam will beused to denote any or all of thethree basic types, where no differ-entiation is required.
SYSTEMDESIGN
Printing mills frequently mix tolulene and isopropyl acetatewith dyes to produce “quick drying” inks. This flammablemixture requires special care to avoid explosions and fire.Larger printing mills typically use steam-heated rolls to drythe printed material. The electric motor-driven condensatepumps that are commonly used, require explosion-proofcontrols/enclosures to accommodate the flammableatmosphere.
During a new project design, the consulting Engineerand Client decided to find a better way to deal with thehazardous environment and costly explosion-proof con-densate pumps. The cost was of particular concernconsidering that the project included 16 dryer rolls on 2printing machines, requiring 4 condensate pumps.
SolutionFour non-electric Pressure Powered Pumps™ were select-ed as alternatives to costlier electric pump sets. Thesewere in addition to the 16 float and thermostatic steamtraps installed on each dryer roll.
Benefits• Installation cost was lower for the Pressure Powered
Pumps™—no electrical wiring/controls required.• Pressure Powered Pumps™ purchase price was sub-
stantially lower.• Pressure Powered Pumps™ operation is safer than with
electric pump/controls.• Without mechanical seals, the Pressure Powered
Pumps™ will operate with lower maintenance cost.
Case in Action: Printing Mill Dryer Roll Drainage
Figure 55Filtered Steam: A filtered steam station produces steam to be usedfor direct injection into food products, culinary steam, or for use insterilizers and autoclaves.
Separator
SampleCooler
PressureReducing
Valve
Filter
FilteredSteam
Clean Steam
51
Steam Qualityvs. Steam PurityIt is important to define the differ-ence between steam quality andpurity.Steam Quality— “The ratio of theweight of dry steam to the weightof dry saturated steam andentrained water. For example, ifthe quality of the steam has beendetermined to be 95%, the wet-steam mixture delivered from theboiler is composed of 5 parts byweight of water, usually in theform of a fine mist, and 95 partsby weight of dry saturated steam.Likewise, if the quality of thesteam has been determined to be100%, there is no wet steamdelivered from the boiler, 100% ofthe steam delivered from the boil-er is dry saturated steam.”Steam Purity— “A quantitativemeasure of contamination ofsteam caused by dissolved solids,volatiles, or particles in vapour orby tiny droplets that may remain inthe steam following primary sepa-ration in the boiler”.
Thus, the three differenttypes of “clean” steam (filtered,clean and pure) can, and will,have different characteristics,summarized in Table 14.Note in particular that:1. The quality of filtered steam
will normally be high becausewater droplets larger than thefilter element rating will beremoved. Clean and puresteam systems will have aquality related to the designand operating characteristicsof the generator, length andinstallation details of distribu-tion system, insulation ofsystem, number and effec-tiveness of mains, drainagepoints, etc.
2. Boiler additives may well bepresent in filtered steam andalso possibly in clean steam,but often this will be limitedby process requirements. Forexample, the FDA restrictsthe use of certain additives,including amines, in anysteam which comes intodirect contact with foods ordairy products.
3. Assuming the generating anddistribution system havebeen designed and installedcorrectly, the particles pre-sent in a pure steam systemwill be water only. Dependenton feed water type, the samemay also apply to cleansteam systems.
SYSTEMDESIGN
Figure 56Clean/Pure Steam Generator and Distribution System
Table 14: Differences in Steam CharacteristicsQuality Purity
Particles Boiler Additives
Filtered High Typically 2.8 microns Normally present
Clean Varies on System Design Varies Limited to process
Pure Varies on System Design Varies None
Condensate
DiaphragmValves
ProcessVessel
Condensate
Condensate
Condensate
PlantSteam
Clean SteamDistribution Main
Pure/CleanSteam
Generator
Pure Water
Main driptraps for
distributionsystem
condensateremoval
Process steam traps foreffective contaminatedcondensate drainage.
Hygienic ball valvesfor isolation on
distribution systems.
Regulatorsfor accurate
pressure control
Separators andfilters for efficient
conditioning ofsteam.
Clean Steam
52
Overall Requirements of a“Clean” Steam SystemThe overall requirements of a“clean” steam system, irrespec-tive of the means of generation ofproduction used, can be very sim-ply stated:
It is essential that thesteam delivered to the point ofuse is of the correct qualityand purity for the process.
In order to achieve this endgoal, there are three key areas ofdesign which must be consideredonce the requirement for cleansteam has been identified.• Point of Use• Distribution• Production
Design and operation ofequipment, piping, components,etc. in all these three areas willinfluence the quality of the finalprocess or products. It is essen-tial for the needs of the userprocess to be the first concern.Must the steam be pyrogen free?Are any boiler additives allowed?Are products of corrosion going toharm the process or product?Must the risk of biological conta-mination be totally prevented? Itis by answering these questions,and perhaps others, which willindicate the required type of pro-duction, design of the distributionsystem, and the operation modesof the user equipment, includingaspects such as steam trapping.
Specific Requirements of“Clean” Steam SystemsClean or pure steam producedfrom water of very high purity ishighly corrosive or “ion hungry”.The corrosive nature becomesmore pronounced as the concen-tration of dissolved ions decreaseswith the resistivity approaching thetheoretical maximum of 18.25megohm/cm at 25°C. In order torecover a more natural ionic bal-ance, it will attack many of thematerials commonly used inpipework systems. To combat this,pipework, fittings, valves andassociated equipment such astraps, must be constructed from
corrosion resistant materials.Typically, a “clean” steam systemof this type will have resistivity val-ues of the condensate in the 2-15megohm/cm range, resulting invery rapid attack of inferior qualitycomponents.
Even in some filtered plantsteam applications, such as in thefood, dairy and pharmaceuticalsindustries, certain corrosion inhibit-ing chemicals may be prohibitedfrom the boiler and steam generat-ing system. Again, condensate isthen likely to be very aggressiveand so careful consideration mustbe given to material selection.
A common problem encoun-tered on clean and pure steamsystems in the pharmaceuticalindustry is that of “rouging”, whichis a fine rusting of pipes and sys-tem components. This isencountered most frequentlywhen low grade stainless steelsare used, and further corrosiondue to galvanic effects can takeplace where dissimilar alloys arepresent in the same system.Unless care is taken with materi-al selection throughout thesystem, corrosion can become amajor problem in terms of:a) Contaminating the system
with products of corrosion,which are undesirable oreven potentially dangerous tothe process or product.
b) Severely reduce life of sys-tem components, increasingmaintenance time, materialreplacement costs, and sys-tem downtime.In order to prevent these
problems, austenitic stainlesssteel should be used throughout,never of lower grade than AISI304. For severe duties, the rec-ommended material is AISI 316or 3161L (alternatively 316Ti) orbetter, passivated to furtherenhance corrosion resistance.
In summary, 316 or 316Lstainless steel is essential inpure steam systems from its pro-duction at the generator rightthrough to the steam traps. Notonly will inferior materials corrodeand fail prematurely, they will also
lead to contamination of the sys-tem as a whole. Note thatalthough filtered plant steam willnot necessarily be so aggressiveby nature, the exclusion of manyof the corrosion inhibiting feedchemicals for end product purityreasons will still demand the useof austenitic stainless steel, neverof lower grade than 304/304L, butpreferable 316/316L.
Clean Steam and CondensateSystem Design The proper and effectivedrainage of condensate from anysteam system is good engineer-ing practice, as it reducescorrosion, erosion, and water-hammer, and increases heattransfer. This becomes evenmore important in “clean” steamsystem, where poor condensatedrainage in the distribution sys-tem or at the user equipment canresult in rapid corrosion and also,under certain conditions, the riskof biological contamination. Thefollowing points should be care-fully considered:• Pipework should have a fall in
the direction of flow of at least1.0 inch in 10 ft., and should beproperly supported to preventsagging.
• Adequate mains and servicepipe steam trapping should beprovided, for example at all ver-tical risers, upstream of controlvalves, and at convenientpoints along any extended pipelength. Trapped drain pointsshould be provided at intervalsof at least every 100 ft.
• Undrained collecting pointsshould not be used, as dirtshould not be present and theyprovide an ideal location forbacterial growth where systemsare shut down.
• Condensate should be allowedto discharge freely from steamtraps using gravity and an airbreak. This air break should beprovided at the manifold outlet orthe closest convenient location(Fig. 57). Where the air breakwould otherwise be in a cleanroom, the potentially harmful
SYSTEMDESIGN
Clean Steam
53
effects of flash steam can be pre-vented by using an expansionpot at the end of the manifold andventing through a filtered ventoutside the clean room. The ventfilter could alternatively be locat-ed at a kill tank, if used (Fig. 58).
• To prevent the risk of contami-nation, the direct connection of“clean” steam and condensateservices should be preventedwherever possible. Under nocircumstances should the con-densate line or manifold liftabove the level of the traps.
• Where the risk of biological con-tamination must be minimized,then care should be taken toselect pipeline products whichare self draining. This becomesmost important in applicationswhere the steam supply is fre-quently turned off, and wheresteam pipeline products areclose coupled to sanitaryprocess lines. Under these con-ditions, microbial growth willbecome possible in any pocketof condensate or process fluidretained in the system. However,where the steam supply is guar-anteed, then this requirementdoes not become so stringent.
• Never “group trap” i.e. alwaysuse a single trap for drainingeach process line, vessel, etc.Failure to do this will invariablycause back-up of condensatein the system.
• The presence of crevices onpipe and component walls canprovide an ideal location formicrobial growth. Pipeline com-ponents which are likely tobecome fouled, such as steamtraps installed on process sys-tems, should be installed sothey can be easily taken out ofservice for thorough cleaning.
• A “clean” steam service shouldnot be interconnected to anyother service which is not ofsanitary design.
• Condensate from clean or puresteam systems should not bereused as make up for theclean/pure steam generationplant.
• Dead legs of piping which arenot open to steam under normaloperating conditions should beavoided by proper initial systemdesign and the careful place-ment of isolation valves. Anydead leg open to steam must beproperly trapped to prevent con-densate build up.
• The use of OD tubing is becom-ing increasingly common forthe distribution of clean steam.Table 15 gives capacities in lb/hfor dry-saturated steam at vari-ous pressures. In order toreduce erosion and noise, it isrecommended that designsshould be based on flow veloc-ities of 100 ft/sec. or less.
SYSTEMDESIGN
Figure 57Steam Trap Discharge Details
Figure 58Steam Trap Discharge—Clean Room
Typical ApplicationSterile barriers, or block and bleedsystems are used extensively inthe biotechnology, pharmaceuti-cal, food, dairy and beverageindustries to prevent contaminat-ing organisms from entering theprocess. A simple example alsoillustrating steam in place, con-densate drainage from a processvessel, is shown in Fig. 59.
In this application, the steamtrap is directly coupled to theprocess pipework, which is nor-mally of sanitary design. It is quitepossible that contamination at thetrap, caused by either biologicalor chemical (corrosion) means,could find its way into the processsystem, thus resulting in failure ofa product batch. Steam traps withcorrosion resistant materials ofconstruction and self drainingfeatures will reduce this risk, tak-ing sanitary standards one stepfurther from the process.
Due to piping arrangements,process fluids will often be flushedthrough the trap. This can oftenresult in plugging if standardindustrial designs of trap are used.
Specialty steam traps arecalled for which have the featuresoutlined above plus the ability forrapid removal from the pipeline andquick disassembly for cleaning.
Clean Area
User Equipment
Vent Filter(alternativelyat kill tank)
Killer Tank/Sewer
CleanSteamTraps
CleanSteamTraps
Condensate
Manifold
To Process Drain
Air Break
Condensate
Air Break
To Process Drain
ManifoldArrangement
Single Trap
CleanSteamTrap
Clean Steam
54
SYSTEMDESIGN
Table 15: Saturated Steam Capacities — OD Tube Capacities in lb/h Tube Size (O.D. x 0.065 inch wall)
Pressure Velocitypsi ft/sec 1/4" 3/8" 1/2" 3/4" 1 11/2" 2" 21/2" 3"
50 — — 5 20 35 90 170 270 3955 80 — 5 10 30 60 145 270 430 635
120 — 5 15 45 85 215 405 650 95050 — 5 10 25 45 110 210 335 490
10 80 — 5 15 35 70 180 330 535 785120 — 10 20 55 110 270 500 800 117550 — 5 10 30 60 155 285 460 675
20 80 — 10 20 50 100 245 460 735 1080120 5 10 25 75 150 370 685 1105 162050 — 5 15 40 80 195 365 585 855
30 80 5 10 30 65 125 310 580 935 1370120 5 15 35 95 190 465 870 1400 205050 — 10 15 50 95 235 440 705 1035
40 80 5 10 25 75 150 375 700 1125 1655120 5 20 40 115 230 556 1050 1690 248050 — 10 20 55 110 275 515 825 1210
50 80 5 15 30 90 180 440 820 1320 1935120 5 20 50 135 265 660 1235 1980 290550 — 10 25 65 125 315 590 945 1385
60 80 5 15 35 105 205 505 940 1510 2215120 5 25 55 155 305 755 1411 2265 332550 5 15 30 80 160 395 735 1180 1730
80 80 5 20 45 130 255 630 1175 1890 2770120 5 30 70 195 380 950 1764 2835 415550 5 15 35 95 190 470 880 1415 2075
100 80 5 25 55 155 305 755 1410 2265 3320120 10 35 85 230 455 1135 2115 3395 497550 5 20 40 115 220 550 1030 1650 2420
120 80 5 30 65 180 355 885 1645 2640 3875120 10 40 95 270 535 1325 2465 3965 5810
A hospital was experiencing continuing problems with anumber of its sterilizers which were having an adverseeffect on both the sterilization process itself and theamount of maintenance required to keep the units in ser-vice. These problems included:• Ineffective sterilization• Prolonged sterilization cycles• Wet and discolored packs• Instrument stains, spotting and rusting• High maintenance of drain traps and controls• Dirty sterilizer chambers requiring frequent cleaning
SolutionIn discussion with the hospital maintenance engineer, theSpirax Sarco Sales Representative offered the opinionthat these problems were a result of a wet and contami-nated steam supply. In a number of cases the steamsupply to the sterilizers was unconditioned, allowing mois-ture and solid particles, such as pipe scale and rust, toenter both the sterilizer jacket and chamber, resulting inthe problems identified by the user.
The solution was to install Spirax Sarco steam filterstations. Each steam filter station is comprised of:• An isolation valve to aid in maintenance.• A separator complete with strainer and drain trap to
remove residual condensate and any entrained moisturebeing carried in suspension within the steam.
• A main line strainer to remove larger solid particles.• A steam filter and drain trap combination.
The steam filter specified was a Spirax Sarco CSF16fitted with a 1 micron absolute filter element. The cleanableCSF16 filter element ensured that 99% of all particles larg-er than 0.1 microns were removed, while the thermostaticsteam trap drained any condensate that formed in the filterbody during operation and periods when the steam supplyto the sterilizer was isolated. These installations resulted insteam supplies free of both moisture and solid particles.
Benefits• Effective sterilization every time• Reduced sterilization cycles and improved productivity• High quality of packs and instruments without spots,
stains or corrosion• Minimal re-work of sterilizer loads• Reduced cleaning and maintenance of sterilizer, drain
traps and controls
Cost SavingsWith the help of the hospital maintenance engineer, asteam filter station payback analysis sheet was completed.The estimated cost of maintenance, the cost associatedwith re-working wet or spotted packs, and the cost due toloss of performance were included in the payback calcula-tion. In total, annual costs were over $25,000 for eachsterilizer. Using this figure a payback period of less thantwo months was established for suitably sized SpiraxSarco steam filter stations.
Case in Action: Hospital Sterilizer
Figure 59Effective Condensate Drainage
Process/Medium
SteamInlet
ProcessTrap
DripTrap
Testing Steam Traps
55
Increasing attention is being paidin modern plants to means ofassessing steam trap perfor-mance. While it is important toknow if a trap is working normallyor is leaking steam into the con-densate return system, most ofthe available methods of assess-ing trap operation are of muchmore restricted usefulness than isappreciated. To explain this, it isnecessary to consider the modeof operation of each type of trapwhen operating and when failed,and then to see if the proposedtest method can distinguishbetween the two conditions.
Temperature Test MethodsOne well established “method” ofchecking traps is to measure tem-perature, either upstream ordownstream. People use pyrome-ters, remote scanners andtemperature sensitive crayons ortapes, while generations of mainte-nance men have thought theycould assess trap performance byspitting onto the trap and watchinghow the spittle reacted! Certainly, ifa trap has failed closed, the tem-perature at the trap will be lowerthan normal, but equally the equip-ment being drained will also cooldown. The trap is not leakingsteam since it is closed, and thisfailure is only a cause of problemsin applications like steam maindrips where the condensate notdischarged at the faulty trap is car-ried along the steam line. Moreusually, the temperature on theinlet side of the trap will be at orclose to the saturation temperatureof steam at whatever pressure isreaching the trap. Even if the trapwere blowing steam, the tempera-ture remains much the same.
The one exception is in thecase of a temperature sensitivetrap, especially one of the bimet-al pattern. If this fails open, thenthe temperature at the inlet sidewill rise from the normal sub-cooled level to saturation values,and this rise may be detectable ifthe steam pressure is a known,constant value.
Measuring temperatures onthe downstream side of a trap, bywhatever method, is even lesslikely to be useful. Let’s look firstat a trap discharging through anopen-ended pipe to atmosphere.The pressure at the trap outletmust be only just above atmos-pheric, and the temperature justabove 212°F.
With any condensate presentwith the steam at temperaturesabove 212°F on the inlet side, thecondensate, after passing throughthe trap will flash down to 212°Fand this temperature is the onethat will be found. Any leakingsteam will help evaporate a littlemore of the condensate withoutincreasing the temperature.Again, the only exception whichmay be encountered is the lowpressure steam heating systemwhere thermostatic traps normal-ly discharge at temperaturesbelow 212°F into atmosphericreturn. A temperature of 212°Fhere may indicate a leaking trap.
Discharge of condensate intoa common return line is moreusual than discharge to an openend, of course. The temperaturein the return line should be thesaturation temperature corre-sponding to the return pressure.Any increase in this temperaturewhich may be detected will showthat the return line pressure hasincreased. However, if trap “A”discharging into a line blowssteam and the pressure in theline increases, then the pressureand temperature at traps “B” and“C” and all others on the line willalso increase. Location of thefaulty trap is still not achieved.
Visual DeterminationsThe release of flashing steamfrom condensate nullifies theeffectiveness of test cocks, orthree-way valves diverting a trapdischarge to an open end for testpurposes. It also restricts the infor-mation which can be gained fromsight glasses. Consider a trap dis-charging to an open end some500 lbs. per hour of condensate
from a pressure of 125 psi. Thesteam tables show that eachpound of water carries 324.7 BTUwhich is a144.5 BTU more than itcan carry as liquid at atmosphericpressure. As the latent heat at 0psig is 970.6 BTU/hr., then144.5/970.6 lbs. of flash steam arereleased per pound of conden-sate, or 14.29%, which is some74.45 pounds per hour. The vol-ume of steam at 0 psig is 26.8 cu.ft. per pound, so some 1,995 cu. ft.per hour of flash steam isreleased. The remaining water,500 - 74.45 = 425.55 lbs. has avolume of about 7.11 cu. ft. perhour. Thus, the discharge from thetrap becomes 1995/1995 + 7.11 =99.65% steam and 0.35% water,by volume.
It is sometimes claimed thatan observer can distinguishbetween this “flash” steam andleakage steam by the color of thesteam at the discharge point.While this may be possible when atrap is leaking steam but has nocondensate load at all, so that onlysteam is seen at the discharge, itis obvious that the presence ofany condensate will make suchdifferentiation virtually impossible.It would be like trying to distinguishbetween 99.65% steam with0.35% water, and perhaps 99.8%steam with 0.20% water!
Trap Discharge SoundsIn a closed piping system, trapdischarge sounds may be a goodindicator of its operation. A simplestethoscope will be of little value,but the sound produced at ultra-high frequencies measured by anultrasonic instrument eliminatesbackground noise interference.Live steam flow produces agreater and steady level of ultra-sound, while flashing condensatetends to have a crackling soundand the level changes with thetrap load. The problem is that theinstrument requires the operatorto make a judgement as to trapcondition which will only be asreliable as his training and expe-rience provide for.
SYSTEMDESIGN
Testing Steam Traps
56
What must be done, using allaudible and visual clues, is todetect normal or abnormalcycling of the discharge. Eventhis method is very fallible, sincethe mode of operation of differenttrap types if not nearly so welldefined as is sometimes thought.Table 16 lists some of the possi-bilities and allows the problem tobe seen more clearly.
It is seen that the “signal” tobe obtained from the trap, whethervisual, audio or temperature, isusually going to be so ambiguousas to rely largely on optimism forinterpretation. The one trap whichis fairly positive in its action is thedisc thermodynamic type—if thisis heard or seen to cycle up to tentimes per minute, it is operatingnormally. The cycling rate increas-es when the trap becomes wornand the characteristic “machinegun” sound clearly indicates theneed for remedial action.
Spira-tec LeakDetector SystemLogic says that if it is not possibleto have a universally applicablemethod of checking steam trapsby examining the traps them-selves, then we must see if it canbe done by checking elsewhere.This is what Spirax Sarco hasdone with the Spira-tec system.See Fig. 61 (page 58).
The Spira-tec detector cham-ber is fitted into the condensate
line on the inlet side of the trap. Ifthere is, at this point, a normal flowof condensate towards the trap,together with a small amount of airand the steam needed to make upheat loss from the body of thesteam trap, then all is normal. Onthe other hand, an increased flowof gas along the pipe indicatesthat the trap is leaking.
The chamber contains aninverted weir. Condensate flowsunder this weir and a small holeat the top equalizes the pressureon each side when the steam trapis working normally. An electrodeon the upstream side of the baffledetects the presence of conden-sate by its conductivity which ismuch higher than that of steam.By plugging in the portable indi-cator, it is possible to check if theelectrical circuit is complete whena visual signal indicates that thetrap is working.
If the trap begins to leaksteam, then the pressure on thedownstream side of the weirbegins to fall. The higher pres-sure on the upstream side dropsthe condensate level below theelectrode and exposes it tosteam. The “conductivity” circuitis broken and the indicator lightgives a “fail” signal.
The advantage of the systemlies in the very positive signalwhich does not require experi-ence of personal judgementbefore it can be interpreted.
Using suitable wiring, the testpoint can be located remote fromthe sensor chamber or it canhave a multi switch to allow up totwelve (12) chambers to bechecked from a single test loca-tion. When appropriate, anelectronic continuous 16-waychecking instrument can monitorthe chambers and this is readilyconnected into a central EnergyManagement System.
The object of detecting leak-ing steam traps is to correct theproblem. This can mean replace-ment of the whole trap, orperhaps of the faulty part of theinternal mechanism. It is veryuseful indeed to be able to checka repaired trap in the workshopbefore it is installed in the line,and many repair shops now use aSpira-tec chamber as part of abench test rig. The diagramshows a simple hookup whichallows suspect or repaired trapsto be positively checked. (Fig. 60)
Cost Of Steam LeaksThe installation and use of theSpira-tec units does involve somecost, and it is necessary to com-pare this with the cost of steamleakages to see if the expenditureis economically justifiable. Sinceall equipment must wear andeventually fail, we need first anestimate of the average life of asteam trap. Let us assume that ina particular installation, this is,
SYSTEMDESIGN
Table 16: Steam Trap Discharge Modes Mode of Operation
Full or UsualTrap Type No Load Light Load Normal Load Overload Failure Mode
Float & Usually continuous but may Closed,Thermosatic No Action cycle at high pressure Continuous A.V. Open
Inverted Bucket Small Dribble Intermittent Intermittent Continuous Open
Balanced PressureThermostatic No Action May Dribble Intermittent Continuous Variable
Bimetallic Usually Dribble May blast atThermostatic No Action Action high pressures Continuous Open
Usually continuousImpulse Small Dribble with blast at high loads Continuous Open
DiscThermo-Dynamic No Action Intermittent Intermittent Continuous Open
Testing Steam Traps
57
say seven (7) years. This meansthat after the first seven years ofthe life of the plant, in any year anaverage of almost 15% of thetraps will fail. With an annualmaintenance campaign, some ofthe traps will fail just after beingchecked and some just before thenext check. On average, the 15%can be said to have failed for halfthe year, or 7-1/2% of traps failedfor the whole year.
Now, most of the traps in anyinstallation, on the mains drip andtracer installations are probably1/2" or 3/4" size and most of themare oversized, perhaps by a factorof up to 10 or more. Let usassume that the condenste load isas high as 25% of the capacity ofthe trap. If the trap were to failwide open, then some 75% of thevalve orifice would be available forsteam flow. The steam loss thenaverages 75% of 7-1/2% of thesteam flow capacity of the wholetrap population, or about 5.62%.
The steam flow through awide open seat clearly dependson both pressure differentials andorifice sizes, and orifice sizes in agiven size of trap such as 1/2"usually are reduced as thedesigned working pressureincreases.
Estimating Trap Steam LossSteam loss through a failed opentrap blowing to atmosphere canbe determined from a variant ofthe Napier formula as follows:Steam Flow in lbs/hr =
24.24 X Pa X D2
Where:Pa = Pressure in psi absoluteD = Diameter of trap orifice
in inchesBy multiplying the steam loss
by hours of operation, steam cost(typically $6.00 per 1,000pounds), and by the number offailed traps, total cost of steamsystem loss may be estimated.
The formula above shouldnot be used to directly comparepotential steam loss of one type
of trap against another becauseof differences in failure modes. Inthose that fail open only theinverted bucket trap orifice blowsfull open. Thermostatic typesusually fail with their orifice atleast partially obstructed by thevalve, and flow through thermo-dynamic types is a function ofmany passageways and must berelated to an equivalent passarea. In every case, no trapbegins losing steam through wear
or malfunction until the leakagearea exceeds that needed by thecondensate load. The cost thenbegins and reaches the maxi-mum calculated only when thetrap fails completely. The objectis, of course to prevent it fromreaching that stage. The steamsystem always functions bestwhen traps are selected that arebest for the application andchecked on a regular basis tocontrol losses.
SYSTEMDESIGN
Table 17: Steam Flow through Orifices Discharging to Atmosphere Steam flow, lb/h, when steam gauge pressure is
Diameter 2 5 10 15 25 50 75 100 125 150 200 250 300(inches) psi psi psi psi psi psi psi psi psi psi psi psi psi
1/32 .31 .47 .58 .70 .94 1.53 2.12 2.7 3.3 3.9 5.1 6.3 7.41/16 1.25 1.86 2.3 2.8 3.8 6.1 8.5 10.8 13.2 15.6 20.3 25.1 29.83/32 2.81 4.20 5.3 6.3 8.45 13.8 19.1 24.4 29.7 35.1 45.7 56.4 67.01/8 4.5 7.5 9.4 11.2 15.0 24.5 34.0 43.4 52.9 62.4 81.3 100 1195/32 7.8 11.7 14.6 17.6 23.5 38.3 53.1 67.9 82.7 97.4 127 156 1863/16 11.2 16.7 21.0 25.3 33.8 55.1 76.4 97.7 119 140 183 226 2687/32 15.3 22.9 28.7 34.4 46.0 75.0 104 133 162 191 249 307 3651/4 20.0 29.8 37.4 45.0 60.1 98.0 136 173 212 250 325 401 4779/32 25.2 37.8 47.4 56.9 76.1 124 172 220 268 316 412 507 6035/16 31.2 46.6 58.5 70.3 94.0 153 212 272 331 390 508 627 74511/32 37.7 56.4 70.7 85.1 114 185 257 329 400 472 615 758 9013/8 44.9 67.1 84.2 101 135 221 306 391 476 561 732 902 1073
13/32 52.7 78.8 98.8 119 159 259 359 459 559 659 859 1059 12597/16 61.1 91.4 115 138 184 300 416 532 648 764 996 1228 146015/32 70.2 105 131 158 211 344 478 611 744 877 1144 1410 16761/2 79.8 119 150 180 241 392 544 695 847 998 1301 1604 1907
Figure 60Steam Trap Test Rig
Inexpensive test stand may beused to test steam trap operation.Valves A, B, C, and D are closed andthe trap is attached. Valve C iscracked and valve D is slowlyopened. The pressure-reducing valveis adjusted to the rated pressure ofthe trap being tested, valve C isclosed, and valve A is opened slowly,allowing condensate flow to the trapuntil it is discharged. Valve B is thenpartially opened to allow the conden-sate to drain out, unloading the trap.Under this final condition, the trapmust close with a tight shutoff. Withsome trap configurations, a smallamount of condensate may remaindownstream of the trap orifice. Slowevaporation of this condensate willcause small amounts of flash steamto flow from the discharge of the trapeven though shutoff is absolute.
Strainer
Steam Supply
PressureReducing Valve
PressureGauge
Spira-tecLoss
Detector
TestTrap
ToAtmosphere
DrainDrain
A
C B
D
Spira-tec Trap Leak Detector System for Checking Steam Traps
58
PurposeThe Spira-tec Trap Leak Detector System is designed to indicate if asteam trap is leaking steam. It can be used to check any known type ormake of trap while it is working.
Equipment1. Sensor chamber fitted immediately upstream of the trap (close
coupled), the same size as the trap.
2. Indicator with cable.
3. Where the sensor chamber is not readily accessible, a RemoteTest Point may be fitted at a convenient position, wired backthrough a junction to the sensor chamber. Remote Test Points foreither one chamber or up to 12 chambers, are available.
4. An Automatic Remote Test Point, capable of interfacing with mostBuilding Management Systems, is also available allowing up to 16steam traps to be continuously scanned for steam wastage.
SYSTEMDESIGN
Figure 61
Multiple inaccessible steam trap checking system—Spira-tec sensor chambers, plug tails, wiring (by installer),remote multiple test point, indicator and indicator cable.
Continuous scanning system—Spira-tec AutomaticRemote test point, sensor chambers, plug tails.
Single inaccessible steam trap checking system—Spira-tec sensor chamber, plug tail, wiring (by installer),remote test point, indicator and indicator cable.
Basic steam trap checking system—Spira-tec sensor chamber, indicator and indicator cable.
SensorChamber
Indicator IndicatorCable
IndicatorMultipleRemote
Test Point
Indicator RemoteTest Point
SensorChamber
PlugTail
Wiringby InstallerJunction
AutomaticRemote
Test Point
Steam Meters
59
The steam meter is the basic toolthat provides an operator or man-ager, information vital inmonitoring and maintaining highefficiency levels within a plant orbuilding. This information can besplit into four categories:
Plant Efficiency • Is idle machinery switched off?• Is the plant loaded to capacity?• Is plant efficiency deteriorating
over time indicating the needfor cleaning, maintenance andreplacement of worn parts?
• When do demand levels peakand who are the major users?This information may lead to achange in production methodsto even out steam usage andease the peak load problemson boiler plant.
Energy Efficiency• Is an energy saving scheme
proving effective?• How does the usage and effi-
ciency of one piece of plantcompare with another?
Process Control• Is the optimum amount of
steam being supplied to a cer-tain process?
• Is that steam at the correctpressure and temperature?
Costing and Custody Transfer• How much steam is being sup-
plied to each customer?• How much steam is each
department or building withinan organization using?
Selecting a Steam MeterBefore selecting a steam meter itis important to understand how ameter’s performance is described.The overall performance of ameter is a combination ofAccuracy, Repeatability andTurndown.
AccuracyThis is the measurement(expressed as a percentage) ofhow close the meter’s indicationof flow is to the actual flowthrough the meter. There are twomethods used to express accura-cy (or percentage of uncertainty)and they have very differentmeanings.a.Measured Value or Actual
ReadingExample: Meter is ranged 0-1000 lb/h and has a specifiedaccuracy of ± 3% of ActualReadingAt an indicated flow rate of1,000 lb/h, the true flow rate liesbetween 1,030 and 970 lb/h.At an indicated flow rate of 100lb/h, the true flow rate liesbetween 103 and 97 lb/h.
b.F.S.D. or Full Scale DeflectionExample: Meter is ranged 0-1000 lb/h and has a specifiedaccuracy of ± 3% FSDAt an indicated flow rate of1,000 lb/h, the true flow rate liesbetween 1,030 and 970 lb/h. At an indicated flow rate of 100lb/h, the true flow rate liesbetween 130 and 70 lb/h (i.e. ±30% of Reading !).
RepeatabilityThis describes the ability of ameter to indicate the same valuefor an identical flowrate over andover again. It should not be con-fused with accuracy i.e. themeter’s repeatability may be excel-lent in that it shows the same valuefor an identical flowrate on severaloccasions, but the reading may beconsistently wrong (or inaccurate).Repeatability is expressed as apercentage of either actual readingor FSD. Good repeatability isimportant for observing trends orfor control e.g. batching.
TurndownSometimes called Turndown
Ratio, Effective Range or evenRangeability. In simple terms, it isthe range of flow rate over whichthe meter will work within theaccuracy and repeatability toler-ances given. If a meter workswithin a certain specified accura-cy at a maximum flow of 1,000lb/h and a minimum flow of 100lb/h, then dividing the maximumby the minimum gives a turndownof 10:1. A wide turndown is partic-ularly important when the flowbeing measured is over a widerange. This could be due to a vari-ation in process e.g. a laundrycould be operating 1 machine or20 machines (20:1 turndown), ordue to seasonal variations inambient temperature if the steamis being used for space heating -the difference in demand betweenmid winter and mid summer canbe considerable. Generally thebigger the turndown the better.The Spirax Sarco family of meterscovers a wide range of sizes, turn-down, accuracy, and repeatabilityas detailed in Table 18.
SYSTEMDESIGN
Table 18: Specification of the Spirax Sarco Meter RangeMeter Type Sizes Accuracy Turndown Repeatability
Orifice Plate 1" -24" ± 3% of Reading 4:1 ± 0.3% of Reading
Gilflo (Made to Order) 2" - 16" ±1% FSD (± 1% of Reading with flow computer) 100:1 ± 0.25% of Reading
Gilflo (S.R.G.) 2" - 8" ± 2% FSD (± 1% of Reading with flow computer) 100:1 ± 0.25% of Reading
Gilflo (I.L.V.A.) 2" - 8" ± 2% FSD (± 1% of Reading with flow computer) 100:1 ± 0.25% of Reading
Spiraflo 1-1/2" - 4" ± 2% of Reading (50% - 100% of meter range) 25-40:1 ± 0.5% of Reading± 1% FSD (1% - 50% of meter range)
Steam Meters
60
Density CompensationFor accurate metering of com-pressible fluids such as gasesand vapors, the actual flowingdensity must be taken intoaccount. This is especially true inthe case of steam. If the actualflowing density of the steam is dif-ferent to the specified density forwhich the meter was originally setup or calibrated, then errors willoccur. These errors can be con-siderable and depend on both themagnitude of difference betweenthe specified density and theactual flowing density, and thetype of meter being used. Example:The steam meter is set up andcalibrated for 100 psig (specificvolume = 3.89 ft3/lb) The steam is actually running at apressure of 85 psig (specific vol-ume = 4.44 ft3/lb). a. Differential Pressure Device
(e.g. Orifice Plate or Gilflo Meter)
Error = s.v. actual -1 x 100√ s.v. specified
Error = 4.44 -1 x 100√ 3.89
Error = 6.8 Therefore the meter will over read by 6.8%
b. Velocity Device(e.g. Vortex Meter)
Error = s.v. actual -1 x 100s.v. specified
Error = 4.44 -1 x 1003.89
Error = 14 Therefore the meter will over read by 14%
In the case of saturated steam,pressure and temperature arerelated and therefore to establishthe flowing density of saturatedsteam, either pressure or temper-ature should be measured. In thecase of superheated steam, pres-sure and temperature can varyindependently from one anotherand therefore to compensate forchanges in density of superheat-ed steam, both pressure andtemperature must be measured.
InstallationNinety percent of all metering fail-ures or problems are installationrelated. Care should be taken toensure that not only is the meterselected suitable for the applica-tion, but that the steam iscorrectly conditioned both toimprove meter performance andprovide a degree of protection,and that the manufacturer’srecommendations regardinginstallation are carefully followed.
Steam ConditioningFor accurate metering of saturat-ed steam, irrespective of themeter type or manufacturer, it isimportant to condition the steamso that it is in the form of, or asclose as possible to, a dry gas.This can be achieved by correctsteam engineering and adequate
trapping to reduce the annular filmof water that clings to the pipewall, and effective separationahead of the meter to removemuch of the entrained droplets ofwater. It is therefore recommend-ed that a steam conditioningstation (as shown in Fig. 62) ispositioned upstream of any type ofmeter on saturated steam applica-tions. This will enhance accuracyand protect the meter from theeffects of water droplets impactingat high velocity. Good steam engi-neering such as the use ofeccentric reducers, effective insu-lation and adequate trapping willalso prevent the dangerous effectsof high velocity slugs of waterknown as waterhammer whichcan not only destroy meters butwill also damage any valves or fit-tings in it’s path.
SYSTEMDESIGN
[ [
[ [
[ [
[ [
Figure 62Steam Conditioning Station
Strainer
Float &ThermostaticSteam Trap
ThermostaticAir Vent
SteamSeparator
CheckValve
IsolatingValve
Steam toMeter
Steam Meters
61
SYSTEMDESIGN
Table 19: Recommended Minimum Straight Lengths (D) for Various Meter Types On Upstream (inlet) side of the primary device Downstream
Meter Type ß Single Two 90° Bends Two or more 90° Bends Reducer Expander Globe Valve Gate Valve All FittingsRatio (3) 90° Bend Same Plane Different Planes 2D to D 0.5D to D Fully Open Fully Open in this table
Orifice Plate 0.30 10 16 34 5 16 18 12 5Orifice Plate 0.35 12 16 36 5 16 18 12 5Orifice Plate 0.40 14 18 36 5 16 20 12 6Orifice Plate 0.45 14 18 38 5 17 20 12 6Orifice Plate 0.50 14 20 40 6 18 22 12 6Orifice Plate 0.55 16 22 44 8 20 24 14 6Orifice Plate 0.60 18 26 48 9 22 26 14 7Orifice Plate 0.65 22 32 54 11 25 28 16 7Orifice Plate 0.70 (4) 28 36 62 14 30 32 20 7Orifice Plate 0.75 36 42 70 22 38 36 24 8Orifice Plate 0.80 46 50 80 30 54 44 30 8Vortex (1) N/A 20 - 40 20 - 40 40 10 - 20 10 - 35 50 20 - 40 5 - 10Spiraflo (2) N/A 6 6 12 6 12 6 6 3 - 6Gilflo (2) N/A 6 6 12 6 12 6 6 3 - 6Gilflo SRG (2) N/A 6 6 12 6 12 6 6 3 - 6Gilflo ILVA (2) N/A 6 6 12 6 12 6 6 3 - 6Notes:1. The table shows the range of straight lengths recommended by various Vortex meter manufacturers.2. Downstream requirements are 3D and 6D when upstream are 6D and 12D respectively.3. ß ratio = Orifice diameter (d) divided by Pipe diameter (D)4. Most Orifice Plates are supplied with a ß ratio of around 0.7 which gives the best pressure recovery without compromising signal strength.
Meter LocationMeters need to be installed indefined lengths of straight pipe toensure accurate and repeatableperformance. These pipe lengthsare usually described in terms ofthe number of pipe diametersupstream and downstream of themeter. For example, an OrificePlate with a Beta ratio of 0.7installed after a 90° bend requiresa minimum of 28 pipe diametersof straight pipe upstream and 7downstream. If the pipe diameteris 6", this is equivalent to 14 feetupstream and 3-1/2 feet down-stream. If the meter is located down-stream of two 90º bends indifferent planes, then the mini-mum straight length requiredupstream of the meter is 62 pipediameters or thirty one feet. Thiscan be difficult to achieve, partic-ularly in fairly complex pipeworksystems, and there may not infact be a location that allowsthese criteria to be met. This is animportant consideration whenselecting a meter.
Table 19 shows the minimum pip-ing requirements for OrificePlates as laid down in the USstandard ASME MFC-3M togeth-er with the manufacturersrecommendations for vortex andspring loaded variable areameters. See Figures II-93, 94, 95,96 (pages 131 and 132).
Figure 63: Moisture Holding Capacity of Air at Varying Temperatures
62
SYSTEMDESIGN
Compressed Air Systems
Air CompressorsHeat is released when air or anygas is compressed. The com-pressor must be cooled to avoidoverheating, usually by circuatingwater through the jackets.Cooling is an important functionwhich must be controlled toensure maximum efficiency.Overcooling wastes water andleads to condensation within thecylinders, with deterioration of thelubricating oils. Undercoolingreduces compressor capacityand can result in serious damageto the compressor. Automatictemperature control of coolingwater flow ensures maximum effi-ciency.
The atmosphere is a mixtureof air and water vapor. Free airhas a greater volume, and mois-ture holding capacity, thancompressed air at the same tem-perature. As the compressed airis cooled after leaving the com-pressor, or between stages,some of the water is precipitated.This water must be drained fromthe system to avoid damage topneumatic valves and tools.
Choice Of Drainer TrapThe quantities of water whichmust be drained from the air arerelatively small, even on quitelarge installations, providing theyare dealt with continuously. It isunusual to need air traps in sizeslarger than 1/2". Except where aworn compressor is allowinglubricating oils to be dischargedwith the compressed air, floatoperated drainers are the bestchoice.
Where the presence in thesystem of water/oil emulsionsinterferes with the operation of floatdrainers, the thermodynamic TDtrap is used. As the TD trap needsan operating pressure of at least50 psi when used as an air drainer,care must be taken when it is usedon small systems. Preferably, theTD’s should be valved off at start-up until the system pressure is upto 50 psi or more.
Sizing Compressed Air TrapsThe amount of water which is to be discharged is determined fromsteam table saturated vapor density or estimated with the help of agraph, Fig. 63 and compression ratio table. An example shows how thisis used.Example:How much water will precipitate from 150 cfm of free air at 70°F and 90%relative humidity when compressed to 100 psig and cooled to 80°F?Air flow = 150 cfm X 60 = 9000 cu. ft/hour.From Fig. 63, at 70°F water in air drawn in will be1.15 X 9000 X 90% = 9.32 lb/h
1000Determine excess moisture due to compression by dividing hourly airflow by factor from Compession Ratio Table 20B (page 64), and convertfor (absolute) temperature.Compression ratio at 100 psig = 7.8Air volume after compression = 9000 X (460 + 80) = 1175 cu. ft./h
7.8 (460 + 70)From Fig. 63, 1000 cu. ft. at 80°F can carry 1.6 lb. of water.1175 cu. ft. will carry 1175 X 1.6 = 1.88 lb/h
1000So, (9.32 lb. – 1.88 lb.) = 7.44 lb/h of water will separate out.
-20 -10 0 10 20 30 40 50
3.0
2.8
2.6
2.4
2.2
2.0
1.8
1.6
1.4
1.2
1.0
.8
.6
.4
.2
0
Air Temp °F
Po
un
ds
Wat
er V
apo
r p
er 1
,000
cu
bic
ft.
at
Sat
ura
tio
n
60 70 80 90 100
63
SYSTEMDESIGN
Distribution LinesThese form the all important linkbetween the compressor and thepoints of usage. If they are under-sized, the desired air flow will beaccompanied by a high pressuredrop. This necessitates extrapower input at the compressor.For example, a pressure at thecompressor of 120 psi where apressure of 100 psi would havesufficed without a high pressuredrop in the lines, needs an addi-tional power input of 10%.
The correct size of com-pressed air lines can be selectedby using Fig. 66 on page 66.Example: 1,000 cu. ft. of free airper minute is to be transmitted at100 PSIG pressure through a 4”line standard weight pipe. Whatwill be the pressure drop due tofriction?
1. Enter the chart at the top atthe point representing 100psig pressure.
2. Proceed vertically downwardto the intersection with hori-zontal line representing 1,000CFM.
3. Next proceed parallel to thediagonal guide lines to theright (or left) to the intersec-tion with the horizontal linerepresenting a 4" line.
4. Proceed vertically downwardto the pressure loss scale atthe bottom of the chart. Youwill note that the pressureloss would be 0.225 psi per100 ft. of pipe.It is usual to size compressed
air lines on velocity, while keepinga watchful eye on pressure drop.
Compressed Air Systems
Drainer InstallationAutomatic drainers are needed atany absorption or refrigerantdryer, and any separator which isinstaled in the air line from theaftercooler, or at the entry to abuilding. They are also needed atthe low points in the distributionlines. (Fig. 64)
Unless fitted close to thepoints being drained, and on lightloads, drainers often need a bal-ance line to allow air to bedisplaced from the piping or thedrainer body as water runs in.The balance line is connectedabove the drain point, and shouldnot be upstream of it. See Fig. II-115 (page 140).
Figure 64Compressed Air System
LiquidDrainTrap
SafetyValve
Strainer
PressureGauge
Separator
Drain Traps
Drain Trap
Receiver
Water CooledAftercooler
CompressorCoolingWater Control
Instrumentationand Control
System
Line Separator
AirGauging
DrainTrap
SprayGun
BreathingMask
PneumaticTool
Machine ToolAir Bearing
AirOperated
Hoist
DrainTrap
DrainTrap
DrainTrap
64
SYSTEMDESIGN
Compressed Air Systems
Table 20A: Pumped Circulation Water Storage Tanks Compressor Capacity, cfm free air 25 50 100 150 200 300 450 600 800
Tank Capacity, gallons 50 100 180 270 440 550 850 1000 1200
Table 20B: Ratio of Compression Gauge Pressure psi 10 20 30 40 50 60 70 80Ratio of Compression 1•68 2•36 3•04 3•72 4•40 5•08 5•76 6•44
Gauge Pressure psi 90 100 110 120 130 140 150 200Ratio of Compression 7•12 7•8 8•48 9•16 9•84 10•52 11•2 14•6
Table 21: Cooling Water Flow Rates Water Flow per
Compressor operating at 100 psi 100 cfm free air
Single Stage 1.2 gpmSingle Stage with Aftercooler 4.8 gpmTwo Stage 2.4 gpmTwo Stage with Aftercooler 6 gpm
An air velocity of 20 to 30 ft/sec-ond or 1200 to 1800 ft/minute, issufficiently low to avoid excessivepressure loss and to prevent re-entrainment of precipitatedmoisture. In short branches to theair-using equipment, volocities upto 60-80 ft/second or 3600-4800ft/minute are often acceptable.
Checking Leakage LossesAir line leaks both waste valuableair and also contribute to pressureloss in mains by adding uselessload to compressors and mains.Hand operated drain valves are acommon source of leakage thatcan be stopped by using reliableautomatic drain traps. Here is asimple way of making a roughcheck of leakage loss. First, esti-mate the total volume of systemfrom the receiver stop valve to thetools, including all branches, sep-arators, etc. Then with noequipment in use, close the stopvalve and with a stop watch notethe time taken for the pressure inthe system to drop by 15 psi. Theleakage loss per minute is:
Cu. ft. of Free AirLoss per Minute
=Volume of System Cu. Ft.Time in Minutes to Drop
Pressure 15 psi
Compressor CoolingAir cooled compressors, formerlyavailable only in the smaller sizes,are now found with capacities upto 750 cfm, and rated for pres-sures up to 200 psi. The cylindersare finned and extra cooling is pro-vided by arranging the flywheel ora fan to direct a stream of air on tothe cylinder. Such compressorsshould not be located in a con-fined space where ambient airtemperatures may rise and pre-vent adequate cooling.
Water cooled compressorshave water jackets around thecylinders, and cooling water is cir-culated through the jackets.Overcooling is wasteful and cost-ly, and can lead to corrosion andwear within the compressor.Temperature control of the cool-ing water is important.
Pumped CirculationLarger single-staged compres-sors may require a pump toincrease the water velocity whenthermo-siphon circulation is tooslow. The size of the water tankshould be discussed with thecompressor manufacturer, but inthe absence of information, Table20A can be used as a guide forcompressors operating at up to100 psi.
Single Pass CoolingThe hook-up shown in Fig. II-103(page 135) is used where waterfrom the local supply is passeddirectly through the compressorto be cooled. With increasingdemands on limited waterresources, many water supplyauthorities do not permit use ofwater in this way, especiallywhere the warmed water is dis-charged to waste, and require theuse of recirculation systems.
When single pass cooling isused, temperature controls willhelp ensure consumption is mini-mized. To avoid the sensorcontrol being in a dead pocket ifthe control valve ever closes, asmall bleed valve is arranged tobypass the control valve. Thisensures a small flow past thesensor at all times.
Many compressor manufactur-ers suggest that the temperature ofthe water leaving the cylinder jack-ets should be in the range of95-120°F. Typical water flow ratesneeded for compressors areshown in Table 21, but again, theseshould be checked with the manu-facturer where possible.The supply of cooling water cansometimes be taken from the soft-ened boiler feed water storagetank. The warmed outlet water thenbecomes a source of pre-heatedmakeup water for the boiler.
65
SYSTEMDESIGN
Compressed Air Systems
Closed Circuit CoolingEspecially with large compres-sors, economies are obtainedwhen the cooling water is recy-cled in a closed circuit. This alsominimizes any scaling in the jack-ets and coolers. The heat may bedissipated at a cooling tower or amechanical cooler, or sometimesused for space heating in adja-cent areas.Usually with closed circuit cool-ing, it is preferable to usethree-way temperature controls.Where cooling towers are used,freeze protection of the towersump may be needed in winterconditions. Often a steam heatingcoil is installed in the sump with atemperature control set to openwhen the water temperature fallsto say 35°F. A three-way temper-ature control diverts water directto the sump instead of to the topof the tower in low temperatureconditions. Heat loss from thesump itself then provides suffi-cient cooling.
Lubricant CoolersOn large reciprocating compres-sors, and especially on rotaryvane compressors, the lubricat-ing oil is usually cooled bypassing it through a heatexchanger. Here it gives up heatto cooling water and again thecoolant flow should be tempera-ture controlled. See Fig. 65.
Figure 65Temperature Control of Water to Oil Cooler
Compressor Equipment GuideApprox. CFM Air =
Compressor HP X 5GPM Cooling Water =
42.5 X HP/Cylinder8.33 X Temp. Rise
of Cooling Water
Air is a vital utility for all process plants, primarily to powercontrol valves, measurement devices and to drive tools,pumps, machinery, etc. Outdoor facilities (i.e. refineriesand chemical plants) are faced with continual problemsrelated to water accumulation in the air system.
Free and compressed air carries varying volumes ofwater at different pressures and temperatures. This affectsthe amount of entrained water that must be drained in dif-ferent parts of the system for effective operation.
Desiccant dryers critical for removing water from com-pressed air distributed to instruments and controls becomewater-logged due to excess moisture entrained in the free-air supplied. When this occurs, the dryers shut down,curtailing air for distribution.
The heat transfer across the wall of distribution pipingcreates additional condensing. Moisture, entrained in the airflow, exceeds the capacity of the coalescent filters installedat the point of use. The air-using equipment is then floodedwith water, affecting proper operation. This can ruin gaugesand instruments and affect control accuracy.
SolutionOver 30 separators with drain traps were installed in prob-lem areas providing proper drainage of equipment.
Benefits• Continuous operation of desiccant dryers, assuring
uninterrupted air supply.• Working with dry air, instrument accuracy is more con-
sistent.• Damage to gauges and other instruments, caused by
entrained water, is prevented, reducing maintenancecost.
• Air hose stations deliver dry air immediately eliminatingdelay/inconvenience of having to manually drain waterfrom the hoses before use.
Case in Action: Air System Moisture Separation/Drainage
Bypass ifnecessary
Reverse ActingTemperature
Control
SensorStrainer
66
SYSTEMDESIGN
Compressed Air Line Pressure Drop
Figure 66: Compressed Air Line Pressure Drop
Table 22: Calculation of Pipe Expansion Expansion (∆) = L0 x ∆t x a (inches)
L0 = Length of pipe between anchors (ft)
∆t = Temperature difference (°F)
a = Expansion coefficient
For Temp. Range 30 32 32 32 32 32 32 32(°F) to to to to to to to to
32 212 400 600 750 900 1100 1300
Mild Steel0.1-0.2% C 7•1 7•8 8•3 8•7 9•0 9•5 9•7 —
Alloy Steel1% Cr. 1/2% Mo 7•7 8•0 8•4 8•8 9•2 9•6 9•8 —
Stainless Steel18% Cr. 8% Ni 10•8 11•1 11•5 11•8 12•1 12•4 12•6 12•8
Expansion Coefficient a x 10-5 (inches)
Example 7•1 x 10-5 = 0.000071
Figure 67: Expansion Chart for Mild Steam PipePipe Expansion
1/2 3/4 1 11/2 2 3 4 6
700600500400
300
200
150125
100
75
50
25
16
Expansion of pipe (inches)8
12 16 20 26 32 40
Temperature difference (°F)100 200 300 400500600
700
800
900
Temperature ofSaturated Steam
psi gauge Temp (°F)5 228
10 24025 26750 29875 320
100 338125 353150 366200 388250 406300 421400 448500 470
.03 .04 .06 .08 .1 .2
12
10
8
6
5
431/2
3
21/2
2
11/2
11/4
1
3/4
1/2
Pressure Drop lbs per sq. inch per 100 feet.3 .4 .5 .6 .8 1.0 1.5 2
10000
600040003000
2000
1000
600
400300
200
100
60
4030
20
10
400 300 200 100 20 10 5 01412 10 8 7Gauge Pressure – lb. per sq. inch Abs. Pres. – P.S.I.A.
Len
gth
of
pip
e (f
eet)
No
min
al P
ipe
Siz
es –
Std
. wei
gh
t p
ipe
Cu
bic F
eet – Free A
ir per M
inu
te
6 5
67
SYSTEMDESIGN
Heat Transfer
Table 23: Heat Transfer Average Heat Loss from Oil in Storage Tanks and Pipe Lines
Position Oil Temperature Unlagged* Lagged*
Tank Sheltered Up to 50°F 1.2 .3Up to 80°F 1.3 .325Up to 100°F 1.4 .35
Tank Exposed Up to 50°F 1.4 .35Up to 80°F 1.5 .375Up to 100°F 1.6 .4
Tank In Pit All Temperatures 1.2 —
Pipe Sheltered Up to 80°F 1.5 .375Line 80 to 260°F 2.3 .575
Pipe Exposed Up to 80°F 1.8 .45Line 80 to 260°F 2.75 .7
*Heat Transfer Rate in BTU/h ft2 °F temperature differencebetween oil and surrounding air
For rough calculations, it may be taken that 1 ton of fuel oiloccupies 36.4 ft3. The specific heat capacity of heavy fuel is0.45 to 0.48 Btu/lb °F.
Heat Transfer from Steam CoilsApproximately 20 Btu/h ft2 of heating surface per °F differencebetween oil and steam temperature.
Heat Transfer from Hot Water CoilsApproximately 10 Btu/h ft2 of heating surface per °F differencebetween oil and water temperature.
Table 24: Heat Transmission Coefficients In Btu per sq. ft. per hr. per °F.
Water Cast Iron Air or Gas 1.4
Water Mild Steel Air or Gas 2.0
Water Copper Air or Gas 2.25
Water Cast Iron Water 40 to 50
Water Mild Steel Water 60 to 70
Water Copper Water 62 to 80
Air Cast Iron Air 1.0
Air Mild Steel Air 1.4
Steam Cast Iron Air 2.0
Steam Mild Steel Air 2.5
Steam Copper Air 3.0
Steam Cast Iron Water 160
Steam Mild Steel Water 185
Steam Copper Water 205
Steam Stainless Steel Water 120
The above values are average coefficients for practically still fluids.
The coefficients are dependent on velocities of heating andheated media on type of heating surface, temperature differenceand other circumstances. For special cases, see literature,and manufacturer’s data.
Table 25: Heat Loss from Open Tanks Liquid Heat Loss From Liquid Suface Heat Loss Through Tank WallsTemp. BTU/ft2 h BTU/ft2 h
°F Evap. Rad. Total Bare InsulationLoss Loss Steel 1" 2" 3"
90 80 50 130 50 12 6 4100 160 70 230 70 15 8 6110 240 90 330 90 19 10 7120 360 110 470 110 23 12 9130 480 135 615 135 27 14 10140 660 160 820 160 31 16 12150 860 180 1040 180 34 18 13160 1100 210 1310 210 38 21 15170 1380 235 1615 235 42 23 16180 1740 260 2000 260 46 25 17190 2160 290 2450 290 50 27 19200 2680 320 3000 320 53 29 20210 3240 360 3590 360 57 31 22
Table 26: Heat Emission Rates from PipesSubmerged in Water
Published Overall Heat Transfer Rates Btu/ft2 h °F
Tank Coils, Steam/Water(Temperature difference 50°F) 100 to 225
Tank Coils, Steam/Water(Temperature difference 100°F) 175 to 300
Tank Coils, Steam/Water(Temperature difference 200°F) 225 to 475
Reasonable Practical Heat Transfer Rates
Tank Coils, low pressure with natural circulation 100
Tank Coils, high pressure with natural circulation 200
Tank Coils, low pressure with assisted circulation 200
Tank Coils, high pressure with assisted circulation 300
Table 27: Heat Emission Coefficients fromPipes Submerged in Miscellaneous Fluids
The viscosity of fluids has a considerable bearing on heat trans-fer characteristics and this varies in any case with temperature.The following figures will therefore serve only as a rough guide.
Immersed steam coil, medium pressure, natural convection.
Btu/ft2 h °F difference
Light Oils 30Heavy Oils 15 to 20Fats* 5 to 10
Immersed steam coil, medium pressure, forced convection.
Btu/ft2 h °F difference
Light Oils (220 SSU at 100°F) 100Medium Oils (1100 SSU at 100°F) 60Heavy Oils (3833 SSU at 100°F) 30
* Certain materials such as tallow and margarine are solid at normal temperatures but have quite low viscosities in the molten state.
Typical Steam Consumption Rates
68
SYSTEMDESIGN
Table 28: Typical Steam Consumption RatesOperating Lbs per hrpressure
PSIG In use Maximum
BAKERIESDough room trough, 8 ft long 10 4Proof boxes, 500 cu ft capacity 7
Ovens: Peel Or Dutch Type 10White bread, 120 sq ft surface 29Rye bread, 10 sq ft surface 58Master Baker Ovens 29Century Reel, w/pb per 100 lb bread 29Rotary ovens, per deck 29Bennett 400, single deck 44Hubbard (any size) 58Middleby-Marshall, w/pb 58Baker-Perkins travel ovens, long tray (per 100 lbs) 13Baker-Perkins travel ovens, short tray (per 100 lbs) 29General Electric 20Fish Duothermic Rotary, per deck 58Revolving ovens: 8-10 bun pan 29
12-18 bun pan 5818-28 bun pan 87
BOTTLE WASHING 5Soft drinks, beer, etc: per 100 bottles/min 310Mill quarts, per 100 cases per hr 58
CANDY and CHOCOLATE 70Candy cooking, 30-gal cooker, 1 hour 46Chocolate melting, jacketed, 24” dia 29Chocolate dip kettles, per 10 sq ft tank surface 29Chocolate tempering, top mixing each 20 sq ft active surface 29Candy kettle per sq ft of jacket 30 60Candy kettle per sq ft of jacket 75 100
CREAMERIES and DAIRIES 15-75Creamery cans 3 per min 310Pasteurizer, per 100 gal heated 20 min 232
DISHWASHERS 10-302-Compartment tub type 58Large conveyor or roller type 58Autosan, colt, depending on size 29 117Champion, depending on size 58 310Hobart Crescent, depending on size 29 186Fan Spray, depending on size 58 248Crescent manual steam control 30Hobart Model AM-5 10Dishwashing machine 15-20 60-70
HOSPITAL EQUIPMENT 40-50Stills, per 100 gal distilled water 102Sterilizers, bed pan 3Sterilizers, dressing, per 10” length, approx. 7Sterilizers, instrument, per 100 cu in approx. 3Sterilizers, water, per 10 gal, approx. 6
Disinfecting Ovens, Double Door: 40-50Up to 50 cu ft, per 10 cu ft approx. 2950 to 100 cu ft, per 10 cu ft approx. 21100 and up, per 10 cu ft, approx. 16
Sterilizers, Non-Pressure TypeFor bottles or pasteurization 40Start with water at 70°F, maintained for 20 minutes at boiling at a depth of 3” 51 69
Instruments and Utensils:Start with water at 70°F, boil vigorously for 20 min: 40
Depth 3-1/2”: Size 8 X 9 X 18” 27 27Depth 3-1/2”: Size 9 X 20 X 10” 30 30Depth 4”: Size 10 X 12 X 22” 39 39Depth 4”: Size 12 X 16 X 24” 60 60Depth 4”: Size 10 X 12 X 36” 66 66Depth 10”: Size 16 X 15 X 20” 92 92Depth 10”: Size 20 X 20 X 24” 144 144
LAUNDRY EQUIPMENT 100Vacuum stills, per 10 gal 16Spotting board, trouser stretcher 29Dress finisher, overcoat shaper, each 58Jacket finisher, Susie Q, each 44
Typical Steam Consumption Rates
69
SYSTEMDESIGN
Table 28: Typical Steam Consumption RatesOperating Lbs per hrpressure
PSIG In use MaximumAir vacuum finishing board, 18” Mushroom Topper, ea. 20Steam irons, each 4
Flat Iron Workers: 10048” X 120”, 1 cylinder 24848” X 120”, 2 cylinder 3104-Roll, 100 to 120” 2176-Roll, 100 to 120” 3418-Roll, 100 to 120” 465
Shirt Equipment 100Single cuff, neckband, yoke No. 3, each 7Double sleeve 13Body 29Bosom 44
Dry Rooms 100Blanket 20Conveyor, per loop, approx. 7Truck, per door, approx. 58Curtain, 50 X 114 29Curtain, 64 X 130 58Starch cooker, per 10 gal cap 7Starcher, per 10-in. length approx. 5Laundry presses per 10-in. length approx. 7Handy irons, per 10-in. length, approx. 5Collar equipment: Collar and Cuff Ironer 21Deodorizer 87Wind Whip, single 58Wind Whip, double 87
Tumblers, General Usage Other Source 10036”, per 10” length, approx. 2940”, per 10” length, approx. 3842”, per 10” length, approx. 52Vorcone, 46” X 120” 310Presses, central vacuum, 42” 20Presses, steam, 42” 29
PLASTIC MOLDINGEach 12 to 15 sq ft platen surface 125 29
PAPER MANUFACTURECorrugators per 1,000 sq ft 175 29Wood pulp paper, per 100 lb paper 50 372
RESTAURANT EQUIPMENT 5-20Standard steam tables, per ft length 36Standard steam tables, per 20 sq ft tank 29Bain Marie, per ft length, 30” wide 13Bain Marie, per 10 sq ft tank 29Coffee urns, per 10 gal, cold make-up 133-compartment egg boiler 13Oyster steamers 13Clam or lobster steamer 29
Steam Jacketed Kettles 5-2010 gal capacity 13 10625 gal stock kettle 29 12440 gal stock kettle 44 14060 gal stock kettle 58 152
Plate And Dish Warmers 5-20Per 100 sq ft shelf 58Per 20 cu ft shelf 29Warming ovens, per 20 cu ft 29Direct vegetable steamer, per compartment 29 80Potato steamer 29 80Morandi Proctor, 30 comp., no return 87Pot sink, steam jets, average use 29Silver burnishers, Tahara 58
SILVER MIRRORINGAverage steam tables 5 102
TIRE SHOPS 100Truck molds, large 87Truck molds, medium 58Passenger molds 29Section, per section 7Puff Irons, each 7
70
SYSTEMDESIGN
Specific Heats and Weights
Table 29: Specific Heats and Weights: Various SolidsSpecific Heat,
Specific B.t.u. per Lb.Material Gravity per °F
Aluminum .................................... 2.55-2.8 .22Andalusite ................................... .17Antimony ..................................... .05Aatite ........................................... .20Asbestos ..................................... 2.1-2.8 .20Augite .......................................... .19Bakelite, wood filler ..................... .33Bakelite, asbestos filler ............... .38Barite........................................... 4.5 .11Barium......................................... 3.5 .07Basalt rock .................................. 2.7-3.2 .20Beryl ............................................ .20Bismuth ....................................... 9.8 .03Borax........................................... 1.7-1.8 .24Boron........................................... 2.32 .31Cadmium..................................... 8.65 .06Calcite, 32-100F.......................... .19Calcite, 32-212F.......................... .20Calcium ....................................... 4.58 .15Carbon ........................................ 1.8-2.1 .17Carborundum .............................. .16Cassiterite ................................... .09Cement, dry ................................ .37Cement, powder.......................... .2Charcoal...................................... .24Chalcopyrite ................................ .13Chromium.................................... 7.1 .12Clay ............................................. 1.8-2.6 .22Coal............................................. 64-.93 .26-.37Cobalt.......................................... 8.9 .11Concrete, stone........................... .19Concrete, cinder.......................... .18Copper ........................................ 8.8-8.95 .09Corundum ................................... .10Diamond...................................... 3.51 .15Dolomite rock .............................. 2.9 .22Fluorite ........................................ .22Fluorspar ..................................... .21Galena......................................... .05Garnet ......................................... .18Glass, common ........................... 2.4-2.8 .20Glass, crystal .............................. 2.9-3.0 .12Glass, plate ................................. 2.45-2.72 .12Glass, wool ................................. .16Gold............................................. 19.25-19.35 .03Granite ........................................ 2.4-2.7 .19Hematite...................................... 5.2 .16Hornblende.................................. 3.0 .20Hypersthene................................ .19Ice, -112F .................................... .35Ice, -40F...................................... .43Ice, -4F........................................ .47
Specific Heat,Specific B.t.u. per Lb.
Material Gravity per °F
Ice, 32F ....................................... .49Iridium ......................................... 21.78-22.42 .03Iron, cast ..................................... 7.03-7.13 .12Iron, wrought ............................... 7.6-7.9 .12Labradorite .................................. .19Lava ............................................ .20Lead ............................................ 11.34 .03Limestone.................................... 2.1-2.86 .22Magnetite .................................... 3.2 .16Magnesium.................................. 1.74 .25Malachite..................................... .18Manganese ................................. 7.42 .11Marble ......................................... 2.6-2.86 .21Mercury ....................................... 13.6 .03Mica............................................. .21Molybdenum................................ 10.2 .06Nickel .......................................... 8.9 .11Oligloclose................................... .21Orthoclose................................... .19Plaster of Paris............................ 1.14Platinum ...................................... 21.45 .03Porcelain ..................................... .26Potassium ................................... 0.86 .13Pyrexglass................................... .20Pyrolusite .................................... .16Pyroxylin plastics ........................ .34-.38Quartz, 55-212F.......................... 2.5-2.8 .19Quartz, 32F ................................. .17Rock salt ..................................... .22Rubber ........................................ .48Sandstone................................... 2.0-2.6 .22Serpentine................................... 2.7-2.8 .26Silk .............................................. .33Silver ........................................... 10.4-10.6 .06Sodium........................................ 0.97 .30Steel ............................................ 7.8 .12Stone........................................... .20Stoneware ................................... .19Talc.............................................. 2.6-2.8 .21Tar ............................................... 1.2 .35Tallurium...................................... 6.0-6.24 .05Tin ............................................... 7.2-7.5 .05Tile, hollow .................................. .15Titanium ...................................... 4.5 .14Topaz........................................... .21Tungsten ..................................... 19.22 .04Vanadium .................................... 5.96 .12Vulcanite ..................................... .33Wood........................................... .35-.99 .32-.48Wool ............................................ 1.32 .33Zinc blend ................................... 3.9-4.2 .11Zinc ............................................. 6.9-7.2 .09
71
SYSTEMDESIGN
Specific Heats and Weights
Table 30: Specific Heats and Weights: Various LiquidsSpecific Heat,
Specific B.t.u. per Lb.Liquid Gravity per °FAcetone....................................... 0.790 .51Alcohol, ethyl 32°F...................... 0.789 .55Alcohol, ethyl, 105°F................... 0.789 .65Alcohol, methyl, 40-50°F............. 0.796 .59Alcohol, methyl, 60-70°F............. 0.796 .60Ammonia, 32°F ........................... 0.62 1.10Ammonia, 104°F ......................... 1.16Ammonia, 176°F ......................... 1.29Ammonia, 212°F ......................... 1.48Ammonia, 238°F ......................... 1.61Anilin ........................................... 1.02 .52Benzol ......................................... .42Calcium Chloride......................... 1.20 .73Castor Oil .................................... .43Citron Oil ..................................... .44Diphenylamine ............................ 1.16 .46Ethyl Ether .................................. .53Ethylene Glycol ........................... .53Fuel Oil........................................ .96 .40Fuel Oil........................................ .91 .44
Specific Heat,Specific B.t.u. per Lb.
Liquid Gravity per °FFuel Oil........................................ .86 .45Fuel Oil........................................ .81 .50Gasoline ...................................... .53Glycerine ..................................... 1.26 .58Kerosene..................................... .48Mercury ....................................... 13.6 .033Naphthalene................................ 1.14 .41Nitrobenzole ................................ .36Olive Oil ...................................... .91-.94 .47Petroleum.................................... .51Potassium Hydrate..................... 1.24 .88Sea Water ................................... 1.0235 .94Sesame Oil ................................. .39Sodium Chloride ......................... 1.19 .79Sodium Hydrate .......................... 1.27 .94Soybean Oil ................................ .47Toluol........................................... .866 .36Turpentine ................................... .87 .41Water........................................... 1 1.00Xylene ......................................... .861-.881 .41
Table 31: Specific Heats and Weights: Gas and VaporsSpecific Heat, Specific Heat,B.t.u. per Lb. B.t.u. per Lb.
Gas or Vapor per °F per °Fat Constant at Constant
Pressure VolumeAcetone....................................... .35 .315Air, dry, 50°F ............................... .24 .172Air, dry, 32-392°F ........................ .24 .173Air, dry, 68-824°F ........................ .25 .178Air, dry 68-1166°F ....................... .25 .184Air, dry, 68-1472°F ...................... .26 .188Alcohol, C2H5OH......................... .45 .398Alcohol, CH3OH .......................... .46 .366Ammonia ..................................... .54 .422Argon........................................... .12 .072Benzene, C6H6............................ .26 .236Bromine....................................... .06 .047Carbon dioxide............................ .20 .150Carbon monoxide........................ .24 .172Carbon disulphide ....................... .16 .132Chlorine....................................... .11 .082Chloroform .................................. .15 .131
Specific Heat, Specific Heat,B.t.u. per Lb. B.t.u. per Lb.
Gas or Vapor per °F per °Fat Constant at Constant
Pressure VolumeEther............................................ .48 .466Hydrochloric acid ........................ .19 .136Hydrogen..................................... 3.41 2.410Hydrogen sulphide ...................... .25 .189Methane ...................................... .59 .446Nitrogen....................................... .24 .170Nitric oxide .................................. .23 .166Nitrogen tetroxide........................ 1.12 1.098Nitrous oxide ............................... .21 .166Oxygen........................................ .22 .157Steam, 1 psia
120-600 °F ................................ .46 .349Steam, 14.7 psia
220-600 °F ................................ .47 .359Steam, 150 psia
360-600 °F ................................ .54 .421Sulphur dioxide ........................... .15 .119
72
SYSTEMDESIGN
Specific Heats and Weights
Table 32: Specific Heats and Weights: FoodstuffsSpecific Heat, Specific Heat,B.t.u. per Lb. B.t.u. per Lb.
Food per °F per °Fabove freezing below freezing
Apples ......................................... .87 .42Apricots, fresh ............................. .88 .43Artichokes ................................... .87 .42Asparagus ................................... .94 .45Asparagus beans ........................ .88 .43Avocados .................................... .72 .37Bananas ...................................... .80 .40Barracuda.................................... .80 .40Bass ............................................ .82 .41Beef, carcass .............................. .68 .48Beef, flank ................................... .56 .32Beef, Loin.................................... .66 .35Beef, rib....................................... .67 .36Beef, round ................................. .74 .38Beef, rump .................................. .62 .34Beef, shanks ............................... .76 .39Beef, corned................................ .63 .34Beets ........................................... .90 .43Blackberries ................................ .87 .42Blueberries .................................. .87 .42Brains .......................................... .84 .41Broccoli ....................................... .92 .44Brussels sprouts ......................... .88 .43Butter........................................... .30 .24Butterfish ..................................... .77 .39Cabbage...................................... .94 .45Carp ............................................ .82 .41Carrots ........................................ .91 .44Cauliflower .................................. .93 .44Celery.......................................... .94 .45Chard .......................................... .93 .44Cherries, sour ............................. .88 .43Cherries, sweet ........................... .84 .41Chicken, squab ........................... .80 .40Chicken, broilers ......................... .77 .39Chicken, fryers ............................ .74 .38Chicken, hens ............................. .65 .35Chicken, capons ......................... .88 .44Clams, meat only ........................ .84 .41Coconut, meat and milk .............. .68 .36Coconut, milk only....................... .95 .45Codfish ........................................ .86 .42Cod Roe...................................... .76 .39Corn ............................................ .84 .423Cowpeas, fresh ........................... .73 .39Cowpeas, dry .............................. .28 .22Crabs........................................... .84 .41Crab apples................................. .85 .41Cranberries ................................. .90 .43Cream ......................................... .90 .38Cucumber.................................... .98 .45Currants ...................................... .97 .45Dandelion greens........................ .88 .43Dates........................................... .20 .007Eels ............................................. .77 .39
Specific Heat, Specific Heat,B.t.u. per Lb. B.t.u. per Lb.
Food per °F per °Fabove freezing below freezing
Eggs............................................ .76 .40Eggplant ...................................... .94 .45Endive ......................................... .95 .45Figs, fresh ................................... .82 .41Figs, dried ................................... .39 .26Figs, candied............................... .37 .26Flounders .................................... .86 .42Flour ............................................ .38 .28Frogs legs ................................... .88 .44Garlic........................................... .79 .40Gizzards ...................................... .78 .39Goose.......................................... .61 .34Gooseberry ................................. .86 .42Granadilla.................................... .84 .41Grapefruit .................................... .91 .44Grapes ........................................ .86 .42Grape juice.................................. .82 .41Guavas........................................ .86 .42Guinea hen ................................. .75 .38Haddoock .................................... .85 .42Halibut ......................................... .80 .40Herring, smokes.......................... .71 .37Horseradish, fresh....................... .79 .40Horseradish, prepared ................ .88 .43Ice Cream ................................... .74 .40Kale ............................................. .89 .43Kidneys ....................................... .81 .40Kidney beans, dried .................... .28 .23Kohlrabi ....................................... .92 .44Kumquats .................................... .85 .41Lamb, carcass............................. .73 .38Lamb, leg .................................... .71 .37Lamb, rib cut ............................... .61 .34Lamb, shoulder ........................... .67 .35Lard ............................................. .54 .31Leeks........................................... .91 .44Lemons ....................................... .91 .44Lemon joice................................. .92 .44Lettuce ........................................ .96 .45Lima beans ................................. .73 .38Limes........................................... .89 .43Lime juice.................................... .93 .44Litchi fruits, dried......................... .39 .26Lobsters ...................................... .82 .41Loganberries ............................... .86 .42Loganberry joice ......................... .91 .44Milk, cow ..................................... .90 .47Mushrooms, fresh ....................... .93 .44Mushrooms, dried ....................... .30 .23Muskmelons ................................ .94 .45Nectarines ................................... .86 .42Nuts............................................. .28 .24Olives, green............................... .80 .40Onions......................................... .90 .43Onions, Welsh............................. .91 .44
73
SYSTEMDESIGN
Specific Heat and Weights
Table 32: Specific Heats and Weights: FoodstuffsSpecific Heat, Specific Heat,B.t.u. per Lb. B.t.u. per Lb.
Food per °F per °Fabove freezing below freezing
Oranges, fresh ............................ .90 .43Orange juice................................ .89 .43Oysters........................................ .84 .41Peaches, Georgia ....................... .87 .42Peaches, N. Carolina .................. .89 .43Peaches, Maryland ..................... .90 .43Peaches, New Jersey ................. .91 .44Peach juice, fresh ....................... .89 .43Pears, Bartlett ............................. .89 .43Pears, Beurre Bosc..................... .85 .41Pears, dried................................. .39 .26Peas, young ................................ .85 .41Peas, medium ............................. .81 .41Peas, old ..................................... .88 .43Peas, split ................................... .28 .23Peppers, ripe............................... .91 .44Perch........................................... .82 .41Persimmins ................................. .72 .37Pheasant ..................................... .75 .36Pickerel ....................................... .84 .41Pickels, sweet ............................. .82 .41Pickels, sour and dill ................... .96 .45Pickels, sweet mixed................... .78 .29Pickels, sour mixed ..................... .95 .45Pig’s feet, pickled ........................ .50 .31Pike ............................................. .84 .41Pineapple, fresh .......................... .88 .43Pineapple, sliced or crushed....... .82 .41Pineapple joice............................ .90 .43Plums .......................................... .89 .43Pomegranate............................... .85 .41Pompano..................................... .77 .39Porgy........................................... .81 .40Pork, bacon................................. .36 .25Pork, ham.................................... .62 .34Pork, loin ..................................... .66 .35Pork, shoulder............................. .59 .33Pork, spareribs............................ .62 .34Pork, smoked ham...................... .65 .35Pork, salted ................................. .31 .24Potatoes ...................................... .82 .41Prickly pears ............................... .91 .43Prunes......................................... .81 .40Pumpkin ...................................... .92 .44Quinces ....................................... .88 .43Rabbit.......................................... .76 .39Radishes ..................................... .95 .45Raisins ........................................ .39 .26Raspberries, black ...................... .85 .41Raspberries, red ......................... .89 .43Raspberry juice, black................. .91 .44Raspberry juice, red.................... .93 .44Reindeer...................................... .73 .37Rhubarb ...................................... .96 .45
Specific Heat, Specific Heat,B.t.u. per Lb. B.t.u. per Lb.
Food per °F per °Fabove freezing below freezing
Rose Apple.................................. .89 .43Rutabagas................................... .91 .44Salmon........................................ .71 .37Sand dab, California ................... .86 .42Sapodilla ..................................... .91 .44Sapote......................................... .73 .37Sauerkraut................................... .93 .44Sausage, beef and pork.............. .56 .32Sausage, bockwurst.................... .71 .37Sausage, bologna ....................... .71 .37Sausage, frankfurt....................... .69 .36Sausage, salami ......................... .45 .28Sardines ...................................... .77 .39Shad............................................ .76 .39Shrimp......................................... .83 .41Spanish mackerel ....................... .73 .39Shad............................................ .76 .39Shrimp......................................... .83 .41Spanish mackerel ....................... .73 .39Strawberries ................................ .95 .45Strawberry juice .......................... .79 .39String beans................................ .91 .44Sturgeon, raw.............................. .83 .41Sturgeon, smoked....................... .71 .37Sugar apple, fresh....................... .79 .39Sweet potatoes ........................... .75 .38Swordfish .................................... .80 .40Terrapin ....................................... .80 .40Tomatoes, red ............................. .95 .45Tomatoes, green ......................... .96 .45Tomato juice................................ .95 .45Tongue, beef ............................... .74 .38Tongue, calf................................. .79 .40Tongue, lamb .............................. .76 .38Tongue, pork ............................... .74 .39Tongue, sheep ............................ .69 .36Tripe, beef ................................... .83 .41Tripe, pickled............................... .89 .43Trout ............................................ .82 .41Tuna ............................................ .76 .39Turkey ......................................... .67 .35Turnips ........................................ .93 .44Turtle ........................................... .84 .41Veal, carcass............................... .74 .38Veal, flank ................................... .65 .35Veal, loin ..................................... .75 .38Veal, rib ....................................... .73 .37Veal, shank ................................. .77 .39Veal, quarter................................ .74 .38Venison ....................................... .78 .39Watercress .................................. .95 .45Watermelons ............................... .94 .45Whitefish ..................................... .76 .39Yams ........................................... .78 .39
74
SYSTEMDESIGN
Conversions
Table 33: ConversionsTo Convert Into Multiply by
AAcres sq. feet 43,560.0Atmospheres cms. of mercury 76.0Atmospheres ft. of water (at 4°C) 33.90Atmospheres in. of mercury (at 0°C) 29.92Atmospheres kgs./sq. cm. 1.0333Atmospheres pounds/sq. in. 14.70
BBarrels (U.S. liquid) gallons 31.5Barrels (oil) gallons (oil) 42.0Btu foot-lbs 778.3Btu grams-calories 252.0Btu horsepower-hrs. 3.931 x 10-4
Btu kilowatt-hrs 2.928 x 10-4
Btu/hr. horsepower 3.931 x 10-4
Btu/hr. watts 0.2931C
Calories, gram (mean) B.t.u. (mean) 3.9685 x 10-3
Centigrade Fahrenheit 9/5(C° + 40) -40Centimeters feet 3.281 x 10-2
Centimeters inches 0.3937Centimeters mils 393.7Centimeters of mercury atmospheres 0.01316Centimeters of mercury feet of water 0.4461Centimeters of mercury pounds/sq. in. 0.1934Circumference radians 6.283Cubic centimeters cu. feet 3.531 x 10-5
Cubic centimeters cu. inches 0.06102Cubic centimeters gallons (U.S. liq.) 2.642 x 10-4
Cubic feet cu. cms. 28,320.0Cubic feet cu. inches 1,728.0Cubic feet gallons (U.S. liq.) 7.481Cubic feet liters 28.32Cubic feet quarts (U.S. liq.) 29.92Cubic feet/min. gallons/sec. 0.1247Cubic feet/min. pounds of water/min. 62.43Cubic inches cu. cms. 16.39Cubic inches gallons 4.329 x 10-3
Cubic inches quarts (U.S. liq.) 0.01732Cubic meters cu. feet 35.31Cubic meters gallons (U.S. liq) 264.2Cubic yards cu. feet 27.0Cubic yards cu. meters 0.7646Cubic yards gallons (U.S. liq.) 202.0
DDegrees (angle) radians 0.01745Drams (apothecaries’ or troy) ounces (avoirdupois) 0.13714Drams (apothecaries’ or troy) ounces (troy) 0.125Drams (U.S. fluid or apothecary) cubic cm. 3.6967Drams grams 1.772Drams grains 27.3437Drams ounces 0.0625
FFahrenheit centigrade 5/9(F + 40) - 40Feet centimeters 30.48Feet kilometers 3.048 x 10-4
Feet meters 0.3048Feet miles (naut.) 1.645 x 10-4
Feet miles (stat.) 1.894 x 10-4
Feet of water atmospheres 0.02950Feet of water in. of mercury 0.8826Feet of water kgs./sq. cm. 0.03045Feet of water kgs./sq. meter 304.8Feet of water pounds/sq. ft. 62.43Feet of water pounds/sq. in. 0.4335Foot-pounds Btu 1.286 x 10-3
Foot-pounds gram-calories 0.3238Foot-pounds hp.-hrs. 5.050 x 10-7
Foot-pounds kilowatt-hrs. 3.766 x 10-7
Foot-pounds/min. Btu/min. 1.286 x 10-8
Foot-pounds/min. horsepower 3.030 x 10-5
Foot-pounds/sec. Btu/hr. 4.6263Furlongs miles 0.125
To Convert Into Multiply byFurlongs feet 660.0
GGallons cu. cms. 3,785.0Gallons cu. feet 0.1337Gallons cu. inches 231.0Gallons cu. meters 3.785 x 10-3
Gallons cu. yards 4.951 x 10-3
Gallons liters 3.785Gallons (liq. Br. Imp.) gallons (U.S. liq.) 1.20095Gallons (U.S.) gallons (Imp.) 0.83267Gallons of water pounds of water 8.3453Gallons/min. cu. ft./sec. 2.228 x 10-3
Gallons/min. liters/sec. 0.06308Gallons/min. cu. ft./hr. 8.0208Grains (troy) grains (avdp.) 1.0Grains (troy) grams 0.06480Grains (troy) ounces (avdp.) 0.286 x 10-3
Grains (troy) pennyweight (troy) 0.04167Grains/U.S. gal. parts/million 17.118Grains/U.S. gal. pounds/million gal. 142.86Grains/lmp. gal. parts/million 14.286Grams grains 15.43Grams ounces (avdp.) 0.03527Grams ounces (troy) 0.03215Grams poundals 0.07093Grams pounds 2.205 x 10-3
Grams/liter parts/million 1,000.0Gram-calories Btu 3.9683 x 10-3
Gram-caloories foot-pounds 3.0880Gram-calories kilowatt-hrs. 1.1630 x 10-4
Gram-calories watt-hrs. 1.1630 x 10-3
HHorsepower Btu/min. 42.40Horsepower foot-lbs./min. 33,000.Horsepower foot-lbs./sec. 550.0Horsepower (metric) horsepower 0.9863
(542.5 ft. lb./sec.) (550 ft. lb./sec.)Horsepower horsepower (metric) 1.014
(550 ft. lb./sec.) (542.5 ft. lb./sec.)Horsepower kilowatts 0.7457Horsepower watts 745.7Horsepower (boiler) Btu/hr. 33,520.Horsepower (boiler) kilowatts 9.803Horsepower-hrs. Btu 2,547.Horsepower-hrs. foot-lbs. 1.98 x 106
Horsepower-hrs. kilowatt-hrs. 0.7457I
Inches centimeters 2.540Inches meters 2.540 x 10-2
Inches millimeters 25.40Inches yards 2.778 x 10-2
Inches of mercury atmospheres 0.03342Inches of mercury feet of water 1.133Inches of mercury kgs./sq. cm. 0.03453Inches of mercury kgs./sq.meter 345.3Inches of mercury pounds/sq. ft. 70.73Inches of mercury pounds/sq. in. 0.4912Inches of water (at 4°C) atmospheres 2.458 x 10-3
Inches of water (at 4°C) inches of mercury 0.07355Inches of water (at 4°C) kgs./sq./ cm. 2.538 x 10-3
Inches of water (at 4°C) ounces/sq. in. 0.5781Inches of water (at 4°C) pounds/sq. ft. 5.204Inches of water (at 4°C) pounds/sq. in. 0.03613
JJoules Btu 9.480 x 10-4
KKilograms grams 1,000.0Kilograms pounds 2.205Kilograms/cu. meter pounds/cu. ft. 0.06243Kilograms/cu. meter pounds/cu. in. 3.613 x 10-5
Kilograms/sq. cm. atmospheres 0.9678Kilograms/sq. cm. feet of water 32.84
75
SYSTEMDESIGN
Conversions
Table 33: ConversionsTo Convert Into Multiply by
Kilograms/sq. cm. inches of mercury 28.96Kilograms/sq. cm. pounds/sq. ft. 2,048Kilograms/sq. cm. pounds/sq. in. 14.22Kilograms/sq. meter atmospheres 9.678 x 10-5
Kilograms/sq. meter feet of water 3.281 x 10-3
Kilograms/sq. meter inches of mercury 2.896 x 10-3
Kilograms/sq. meter pounds/sq. ft. 0.2048Kilograms/sq. meter pounds/sq. in. 1.422 x 10-3
Kilograms/sq. mm. kgs./sq. meter 106
Kilogram-calories Btu 3.968Kilogram-calories foot-pounds 3,088.Kilogram-calories hp-hrs. 1.560 x 10-3
Kilogram-calories kilowatt-hrs. 1.163 x 10-3
Kilogram meters Btu 9.294 x 10-3
Kilometers centimeters 105
Kilometers feet 3,281.Kilometers miles 0.6214Kilowatts Btu/min. 56.87Kilowatts foot-lbs/min. 4.426 x 104
Kilowatts foot-lbs/sec. 737.6Kilowatts horsepower 1.341Kilowatts watts 1,000.0Kilowatt-hrs Btu 3,413.Kilowatt-hrs. foot-lbs. 2.655 x 106
Kilowatt-hrs horsepower-hrs 1.341Knots statute miles/hr. 1.151
LLiters cu. cm. 1,000.0Liters cu. feet 0.03531Liters cu. inches 61.02Liters gallons (U.S. liq.) 0.2642
MMeters centimeters 100.0Meters feet 3.281Meters inches 39.37Meters millimeters 1,000.0Meters yards 1.094Microns inches 39.37 x 10-6
Microns meters 1 x 10-6
Miles (statute) feet 5.280.Miles (statute) kilometers 1.609Miles/hr. cms./sec. 44.70Miles/hr. feet/min. 88.Mils inches 0.001Mils yards 2.778 x 10-5
NNepers decibels 8.686
OOhms megohms 10-6
Ohms microhms 106
Ounces (avoirdupois) drams 16.0Ounces (avoirdupois) grains 437.5Ounces (avoirdupois grams 28.35Ounces (avoirdupois) pounds 0.0625Ounces (avoirdupois ounces (troy) 0.9115Ounces (troy) grains 480.0Ounces (troy) grains 31.10Ounces (troy) ounces (avdp.) 1.09714Ounces (troy) pounds (troy) 0.08333
PParts/million grains/U.S. gal. 0.0584Parts/million grains/lmp. gal 0.07016Parts/million pounds/million gal. 8.33Pounds (avoirdupois) ounces (troy) 14.58Pounds (avoirdupois) drams 256.Pounds (avoirdupois) grains 7,000.Pounds (avoirdupois) grams 453.59Pounds (avoirdupois) kilograms 0.454Pounds (avoirdupois) ounces 16.0Pounds (avoirdupois) tons (short) 0.0005
To Convert Into Multiply by
Pounds (troy) ounces (avdp.) 13.1657Pounds of water cu. feet 0.01602Pounds of water cu. inches 27.68Pounds of water gallons 0.1198Pounds of water/min. cu. ft/sec. 2.670 x 10-4
Pounds/cu. ft. grams/cu. cm. 0.01602Pounds/cu. ft. kgs./cu. meter 16.02Pounds/cu. ft. pounds/cu. in. 5.787 x 10-4
Pounds/cu. in. pounds/cu. ft. 1,728.Pounds/sq. ft. atmospheres 4.725 x 10-4
Pounds/sq. ft. feet of water 0.01602Pounds/sq. ft. inches of mercury 0.01414Pounds/sq. in. atmospheres 0.06804Pounds/sq. in. feet of water 2.307Pounds/sq. in. inches of mercury 2.036Pounds/sq. in. kgs./sq. meter 703.1Pounds/sq. in. pounds/sq. ft. 144.0
RRadians degrees 57.30Revolutions/min. degrees/sec. 6.0Revolutions/min. radians/sec. 0.1047Revolutions/min. revs./sec. 0.01667
SSquare centimeters sq. feet 1.076 x 10-3
Square centimeters sq. inches 0.1550Square centimeters sq. meters 0.0001Square centimeters sq. millimeters 100.0Square feet acres 2.296 x 10-5
Square feet sq. cms. 929.0Square feet sq. inches 144.0Square feet sq. miles 3.587 x 10-6
Square inches sq. cms. 6.452Square inches sq. feet 6.944 x 10-3
Square inches sq. yards 7.716 x 10-4
Square meters sq. feet 10.76Square meters sq. inches 1,550.Square meters sq. millimeters 106
Square meters sq. yards 1.196Square millimeters sq. inches 1.550 x 10-3
Square yards sq. feet 9.0Square yards sq. inches 1,296.Square yards sq. meters 0.8361
TTemperature (°C) + 273 absolute temperature (°C) 1.0Temperature (°C) + 17.78 temperature (°F) 1.8Temperature (°F) + 460 absolute temperature (°F) 1.0Temperature (°F) - 32 temperature (°C) 5/9Tons (long) kilograms 1,016.Tons (long) pounds 2,240.Tons (long) tons (short) 1.120Tons (metric) kilograms 1,000.Tons (metric) pounds 2,205.Tons (short) kilograms 907.2Tons (short) pounds 2,000.Tons (short) tons (long) 0.89287Tons of water/24 hrs. pounds of water/hr. 83.333Tons of water/24 hrs. gallons/min. 0.16643Tons of water/24 hrs. cu. ft./hr. 1.3349
WWatts Btu/hr. 3.4129Watts Btu/min. 0.05688Watts horsepower 1.341 x 10-3
Watts horsepower (metric) 1.360 x 10-3
Watts kilowatts 0.001Watts (Abs.) B.t.u. (mean)/min. 0.056884Watt-hours Btu 3.413Watt-hours horsepower-hrs. 1.341 x 10-3
YYards centimeters 91.44Yards kilometers 9.144 x 10-4
Yards meters 0.9144
76
SYSTEMDESIGN
Flow of Water through Schedule 40 Steel Pipe
Table 34: Flow of Water through Schedule 40 Steel PipePressure Drop per 1,000 Feet of Schedule 40 Steel Pipe, in pounds per square inch
Dschg Vel. Pres- Vel. Pres- Vel. Pres- Vel. Pres- Vel. Pres- Vel. Pres- Vel. Pres- Vel. Pres- Vel. Pres-Gals. Ft. per sure Ft. per sure Ft. per sure Ft. per sure Ft. per sue Ft. per sure Ft. per sure Ft. per sure Ft. per sure
per Min. Sec. Drop Sec. Drop Sec. Drop Sec. Drop Sec. Drop Sec. Drop Sec. Drop Sec. Drop Sec. Drop
1"1 .37 0.49 1-1/4"2 .74 1.70 0.43 .045 1-1/2"3 1.12 3.53 0.64 0.94 0.47 0.444 1.49 5.94 0.86 1.55 0.63 0.74 2"5 1.86 9.02 1.07 2.36 0.79 1.126 2.24 12.25 1.28 3.30 0.95 1.53 .57 0.46 2-1/2"8 2.98 21.1 1.72 5.52 1.26 2.63 .76 .075
10 3.72 30.8 2.14 8.34 1.57 3.86 .96 1.14 .67 0.4815 5.60 64.6 3.21 17.6 2.36 8.13 1.43 2.33 1.00 0.99 3" 3-1/2"20 7.44 110.5 4.29 29.1 3.15 13.5 1.91 3.86 1.34 1.64 .87 0.5925 5.36 43.7 3.94 20.2 2.39 5.81 1.68 2.48 1.08 0.67 .81 0.42 4"30 6.43 62.9 4.72 29.1 2.87 8.04 2.01 3.43 1.30 1.21 .97 0.6035 7.51 82.5 5.51 38.2 3.35 10.95 2.35 4.49 1.52 1.58 1.14 0.79 .88 0.4240 6.30 47.8 3.82 13.7 2.68 5.88 1.74 2.06 1.30 1.00 1.01 0.5345 7.08 60.6 4.30 17.4 3.00 7.14 1.95 2.51 1.46 1.21 1.13 0.6750 7.87 74.7 4.78 20.6 3.35 8.82 2.17 3.10 1.62 1.44 1.26 0.80 5"60 5.74 29.6 4.02 12.2 2.60 4.29 1.95 2.07 1.51 1.1070 6.69 38.6 4.69 15.3 3.04 5.84 2.27 2.71 1.76 1.50 1.12 0.4880 6" 7.65 50.3 5.37 21.7 3.48 7.62 2.59 3.53 2.01 1.87 1.28 0.6390 8.60 63.6 6.04 26.1 3.91 9.22 2.92 4.46 2.26 2.37 1.44 0.80
100 1.11 0.39 9.56 75.1 6.71 32.3 4.34 11.4 3.24 5.27 2.52 2.81 1.60 0.95125 1.39 0.56 8.38 48.2 5.42 17.1 4.05 7.86 3.15 4.38 2.00 1.48150 1.67 0.78 10.06 60.4 6.51 23.5 4.86 11.3 3.78 6.02 2.41 2.04175 1.94 1.06 8" 11.73 90.0 7.59 32.0 5.67 14.7 4.41 8.20 2.81 2.78200 2.22 1.32 8.68 39.7 6.48 19.2 5.04 10.2 3.21 3.46225 2.50 1.66 1.44 0.44 9.77 50.2 7.29 23.1 5.67 12.9 3.61 4.37250 2.78 2.05 1.60 0.55 10.85 61.9 8.10 28.5 6.30 15.9 4.01 5.14275 3.06 2.36 1.76 0.63 11.94 75.0 8.91 34.4 6.93 18.3 4.41 6.22300 3.33 2.80 1.92 0.75 13.02 84.7 9.72 40.9 7.56 21.8 4.81 7.41325 3.61 3.29 2.08 0.88 10.53 45.5 8.18 25.5 5.21 8.25350 3.89 3.62 2.24 0.97 11.35 52.7 8.82 29.7 5.61 9.57375 4.16 4.16 2.40 1.11 12.17 60.7 9.45 32.3 6.01 11.0400 4.44 4.72 2.56 1.27 12.97 68.9 10.08 36.7 6.41 12.5425 4.72 5.34 2.72 1.43 10" 13.78 77.8 10.70 41.5 6.82 14.1450 5.00 5.96 2.88 1.60 14.59 87.3 11.33 46.5 7.22 15.0475 5.27 6.66 3.04 1.69 1.93 0.30 11.96 51.7 7.62 16.7500 5.55 7.39 3.20 1.87 2.04 0.63 12.59 57.3 8.02 18.5550 6.11 8.94 3.53 2.26 2.24 0.70 13.84 69.3 8.82 22.4600 6.66 10.6 3.85 2.70 2.44 0.86 12" 15.10 82.5 9.62 26.7650 7.21 11.8 4.17 3.16 2.65 1.01 10.42 31.3700 7.77 13.7 4.49 3.69 2.85 1.18 2.01 0.48 11.22 36.3750 8.32 15.7 4.81 4.21 3.05 1.35 2.15 0.55 14" 12.02 41.6800 8.88 17.8 5.13 4.79 3.26 1.54 2.29 0.62 12.82 44.7850 9.44 20.2 5.45 5.11 3.46 1.74 2.44 0.70 2.02 0.43 13.62 50.5900 10.00 22.6 5.77 5.73 3.66 1.94 2.58 0.79 2.14 0.48 14.42 56.6950 10.55 23.7 6.09 6.38 3.87 2.23 2.72 0.88 2.25 0.53 15.22 63.1
1,000 11.10 26.3 6.41 7.08 4.07 2.40 2.87 0.98 2.38 0.59 16" 16.02 70.01,100 12.22 31.8 7.05 8.56 4.48 2.74 3.16 1.18 2.61 0.68 17.63 84.61,200 13.32 37.8 7.69 10.2 4.88 3.27 3.45 1.40 2.85 0.81 2.18 0.401,300 14.43 44.4 8.33 11.3 5.29 3.86 3.73 1.56 3.09 0.95 2.36 0.471,400 15.54 51.5 8.97 13.0 5.70 4.44 4.02 1.80 3.32 1.10 2.54 0.541,500 16.65 55.5 9.62 15.0 6.10 5.11 4.30 2.07 3.55 1.19 2.73 0.62 18"1,600 17.76 63.1 10.26 17.0 6.51 5.46 4.59 2.36 3.80 1.35 2.91 0.711,800 19.98 79.8 11.54 21.6 7.32 6.91 5.16 2.98 4.27 1.71 3.27 0.85 2.58 0.482,000 22.20 98.5 12.83 25.0 8.13 8.54 5.73 3.47 4.74 2.11 3.63 1.05 2.88 0.562,500 16.03 39.0 10.18 12.5 7.17 5.41 5.92 3.09 4.54 1.63 3.59 0.88 20"3,000 19.24 52.4 12.21 18.0 8.60 7.31 7.12 4.45 5.45 2.21 4.31 1.27 3.45 0.73 24"3,500 22.43 71.4 14.25 22.9 10.03 9.95 8.32 6.18 6.35 3.00 5.03 1.52 4.03 0.944,000 25.65 93.3 16.28 29.9 11.48 13.0 9.49 7.92 7.25 3.92 5.74 2.12 4.61 1.22 3.19 0.514,500 18.31 37.8 12.90 15.4 10.67 9.36 8.17 4.97 6.47 2.50 5.19 1.55 3.59 0.605,000 20.35 46.7 14.34 18.9 11.84 11.6 9.08 5.72 7.17 3.08 5.76 1.78 3.99 0.746,000 24.42 67.2 17.21 27.3 14.32 15.4 10.88 8.24 8.62 4.45 6.92 2.57 4.80 1.007,000 28.50 85.1 20.08 37.2 16.60 21.0 12.69 12.2 10.04 6.06 8.06 3.50 5.68 1.368,000 22.95 45.1 18.98 27.4 14.52 13.6 11.48 7.34 9.23 4.57 6.38 1.789,000 25.80 57.0 21.35 34.7 16.32 17.2 12.92 9.20 10.37 5.36 7.19 2.25
10,000 28.63 70.4 23.75 42.9 18.16 21.2 14.37 11.5 11.53 6.63 7.96 2.7812,000 34.38 93.6 28.50 61.8 21.80 30.9 17.23 16.5 13.83 9.54 9.57 3.7114,000 33.20 84.0 25.42 41.6 20.10 20.7 16.14 12.0 11.18 5.0516,000 29.05 54.4 22.96 27.1 18.43 15.7 12.77 6.60
77
SYSTEMDESIGN
Friction Loss for Water in Feet per 100 ft. Schedule 40 Steel Pipe
Table 35: Friction Loss* for Water in Feet per 100 ft. Schedule 40 Steel PipeU.S. Velocity hf
Gal/Min. Ft/Sec. Friction
3/8" PIPE1.4 2.35 9.031.6 2.68 11.61.8 3.02 14.32.0 3.36 17.32.5 4.20 26.03.0 5.04 36.03.5 5.88 49.04.0 6.72 63.25.0 8.40 96.16 10.08 1367 11.8 1828 13.4 2369 15.1 297
10 16.8 364
1/2" PIPE2 2.11 5.502.5 2.64 8.243 3.17 11.53.5 3.70 15.34.0 4.22 19.75 5.28 29.76 6.34 42.07 7.39 56.08 8.45 72.19 9.50 90.1
10 10.56 110.612 12.7 15614 14.8 21116 16.9 270
3/4" PIPE4.0 2.41 4.855 3.01 7.276 3.61 10.27 4.21 13.68 4.81 17.39 5.42 21.6
10 6.02 26.512 7.22 37.514 8.42 50.016 9.63 64.818 10.8 80.920 12.0 99.022 13.2 12024 14.4 14126 15.6 16528 16.8 189
1" PIPE6 2.23 3.168 2.97 5.20
10 3.71 7.9012 4.45 11.114 5.20 14.716 5.94 19.018 6.68 23.720 7.42 28.922 8.17 34.824 8.91 41.026 9.65 47.828 10.39 55.130 11.1 62.935 13.0 84.440 14.8 10945 16.7 13750 18.6 168
* Aging Factor Included
U.S. Velocity hfGal/Min. Ft/Sec. Friction
1-1/4" PIPE12 2.57 2.8514 3.00 3.7716 3.43 4.8318 3.86 6.0020 4.29 7.3022 4.72 8.7224 5.15 10.2726 5.58 11.9428 6.01 13.730 6.44 15.635 7.51 21.940 8.58 27.145 9.65 33.850 10.7 41.455 11.8 49.760 12.9 58.665 13.9 68.670 15.0 79.275 16.1 90.6
1-1/2" PIPE16 2.52 2.2618 2.84 2.7920 3.15 3.3822 3.47 4.0524 3.78 4.7626 4.10 5.5428 4.41 6.3430 4.73 7.2035 5.51 9.6340 6.30 12.4145 7.04 15.4950 7.88 18.955 8.67 22.760 9.46 26.765 10.24 31.270 11.03 36.075 11.8 41.280 12.6 46.685 13.4 52.490 14.2 58.795 15.0 65.0
100 15.8 71.6
2" PIPE25 2.39 1.4830 2.87 2.1035 3.35 2.7940 3.82 3.5745 4.30 4.4050 4.78 5.3760 5.74 7.5870 6.69 10.280 7.65 13.190 8.60 16.3
100 9.56 20.0120 11.5 28.5140 13.4 38.2160 15.3 49.5
2-1/2" PIPE35 2.35 1.1540 2.68 1.4745 3.02 1.8450 3.35 2.2360 4.02 3.1370 4.69 4.1880 5.36 5.3690 6.03 6.69
100 6.70 8.18120 8.04 11.5140 9.38 15.5160 10.7 20.0180 12.1 25.2200 13.4 30.7220 14.7 37.1240 16.1 43.8
U.S. Velocity hfGal/Min. Ft/Sec. Friction
3" PIPE50 2.17 .76260 2.60 1.0670 3.04 1.4080 3.47 1.8190 3.91 2.26
100 4.34 2.75120 5.21 3.88140 6.08 5.19160 6.94 6.68180 7.81 8.38200 8.68 10.2220 9.55 12.3240 10.4 14.5260 11.3 16.9280 12.2 19.5300 13.0 22.1350 15.2 30
4" PIPE100 2.52 .718120 3.02 1.01140 3.53 1.35160 4.03 1.71180 4.54 2.14200 5.04 2.61220 5.54 3.13240 6.05 3.70260 6.55 4.30280 7.06 4.95300 7.56 5.63350 8.82 7.54400 10.10 9.75450 11.4 12.3500 12.6 14.4550 13.9 18.1600 15.1 21.4
5" PIPE160 2.57 .557180 2.89 .698200 3.21 .847220 3.53 1.01240 3.85 1.19260 4.17 1.38300 4.81 1.82350 5.61 2.43400 6.41 3.13450 7.22 3.92500 8.02 4.79600 9.62 6.77700 11.2 9.13800 12.8 11.8900 14.4 14.8
1000 16.0 18.2
6" PIPE220 2.44 .411240 2.66 .482260 2.89 .560300 3.33 .733350 3.89 .980400 4.44 1.25450 5.00 1.56500 5.55 1.91600 6.66 2.69700 7.77 3.60800 8.88 4.64900 9.99 5.81
1000 11.1 7.101100 12.2 8.521200 13.3 10.11300 14.4 11.71400 15.5 13.6
78
SYSTEMDESIGN
Moisture Content of Air
Figure 68: Ashrae Psychrometric Chart No. 1
79
SYSTEMDESIGN
Friction Head Loss for Water
Table 36: Equivalent Length in Feet of New Straight Pipe for Valves and Fittings for Turbulent Flow OnlyPipe Size
1/4 3/8 1/2 3/4 1 11/4 11/2 2 21/2 3 4 5 6 8 10 12 14 16 18 20 24
2.3 3.1 3.6 4.4 5.2 6.6 7.4 8.5 9.3 11 139.0 11
.92 1.2 1.6 2.1 2.4 3.1 3.6 4.4 5.9 7.3 8.9 12 14 17 18 21 23 25 303.6 4.8 7.2 9.8 12 15 17 19 22 24 28
1.5 2.0 2.2 2.3 2.7 3.2 3.4 3.6 3.6 4.0 4.63.3 3.7
1.1 1.3 1.6 2.0 2.3 2.7 2.9 3.4 4.2 5.0 5.7 7.0 8.0 9.0 9.4 10 11 12 142.8 3.4 4.7 5.7 6.8 7.8 8.6 9.6 11 11 13
.34 .52 .71 .92 1.3 1.7 2.1 2.7 3.2 4.0 5.53.3 4.5
.45 .59 .81 1.1 1.3 1.7 2.0 2.6 3.5 4.5 5.6 7.7 9.0 11 13 15 16 18 222.1 2.9 4.5 6.3 8.1 9.7 12 13 15 17 20
.79 1.2 1.7 2.4 3.2 4.6 5.6 7.7 9.3 12 179.9 14
.69 .82 1.0 1.3 1.5 1.8 1.9 2.2 2.8 3.3 3.8 4.7 5.2 6.0 6.4 7.2 7.6 8.2 9.61.9 2.2 3.1 3.9 4.6 5.2 5.9 6.5 7.2 7.7 8.8
2.4 3.5 4.2 5.3 6.6 8.7 9.9 12 13 17 2114 17
2.0 2.6 3.3 4.4 5.2 6.6 7.5 9.4 12 15 18 24 30 34 37 43 47 52 627.7 10 15 20 25 30 35 39 44 49 57
2.3 3.1 3.6 4.4 5.2 6.6 7.4 8.5 9.3 11 139.0 11
.92 1.2 1.6 2.1 2.4 3.1 3.6 4.4 5.9 7.3 8.9 12 14 17 19 21 23 25 303.6 4.8 7.2 9.8 12 15 17 19 22 24 28
1.1 1.3 1..6 2.0 2.3 2.7 2.9 3.4 4.2 5.0 5.7 7.0 8.0 9.0 9.4 10 11 12 142.8 3.4 4.7 5.7 6.8 7.8 8.6 9.6 11 11 13
21 22 22 24 29 37 42 54 62 79 11065 86
38 40 45 54 59 70 77 94 120 150 190 260 310 39077 99 150 210 270 330
.32 .45 .56 .67 .84 1.1 1.2 1.5 1.7 1.9 2.51.6 2.0
2.6 2.7 2.8 2.9 3.1 3.2 3.2 3.2 3.2 3.2 3.2 3.2 3.2 3.22.3 2.4 2.6 2.7 2.8 2.9 2.9 3.0 3.0 3.0 3.0
12.8 15 15 15 17 18 18 18 18 18 1815 15
15 15 17 18 18 21 22 28 38 50 63 90 120 140 160 190 210 240 30023 31 52 74 98 120 150 170 200 230 280
7.2 7.3 8.0 8.8 11 13 15 19 22 27 3822 31
3.8 5.3 7.2 10 12 17 21 27 38 50 63 90 120 14022 31 52 74 98 120
.14 .18 .21 .24 .29 .36 .39 .45 .47 .53 .65.44 .52
.04 .07 .10 .13 .18 .26 .31 .43 .52 .67 .95 1.3 1.6 2.3 2.9 3.5 4.0 4.7 5.3 6.1 7.6.55 .77 1.3 1.9 2.4 3.0 3.6 4.3 5.0 5.7 7.0
.44 .68 .96 1.3 1.8 2.6 3.1 4.3 5.2 6.7 9.5 13 16 23 29 35 40 47 53 61 765.5 7.7 13 19 24 30 36 43 50 57 70
.88 1.4 1.9 2.6 3.6 5.1 6.2 8.5 10 13 19 25 32 45 58 70 80 95 110 120 15011 15 26 37 49 61 73 86 100 110 140
4.6 5.0 6.6 7.7 18 20 27 29 34 42 53 61
h = (V1 - V2)2 FEET OF LIQUID; IF V2 = 0 h = V12
FEET OF LIQUID2g 2g
Reprinted from the STANDARDS OF THE HYDRAULIC INSTITUTE, Eleventh Edition.Copyright 1965 by the Hydraulic Institute, 122 East 42nd Street, New York, New York 10017.
Fittings
ScrewedSteelC.I.
FlangedSteelC.I.
ScrewedSteelC.I.
FlangedSteelC.I.
ScrewedSteelC.I.
FlangedSteelC.I.
ScrewedSteelC.I.
FlangedSteelC.I.
ScrewedSteelC.I.
FlangedSteelC.I.
ScrewedSteelC.I.
Reg. SteelFlanged C.I.
Long Rad SteelFlanged C.I.
ScrewedSteelC.I.
FlangedSteelC.I.
ScrewedSteelC.I.
FlangedSteelC.I.
ScrewedSteelC.I.
FlangedSteelC.I.
ScrewedSteelC.I.
FlangedSteelC.I.
ScrewedSteelC.I.
Bell Mouth SteelInlet C.I.
Square SteelMouth Inlet C.I.
Re-entrant SteelPipe C.I.
Y-Strainer
SuddenEnlarge-
ment
Regular90° ELL
Long Radius90° ELL
Regular45° ELL
Tee- LineFlow
Tee- BranchFlow
180°ReturnBend
Globe Valve
Gate Valve
Angle Valve
Swing CheckValve
Couplingor Union
80
SYSTEMDESIGN
ANSI Flange Standards
Table 37: ANSI Flange StandardsAll Dimensions are in Inches
Pipe Size 1/2 3/4 1 11/4 11/2 2 21/2 3 31/2 4 5 6 8 10 12125 lb CAST IRON – ANSIDiameter of Flange – – 41/4 45/8 5 6 7 71/2 81/2 9 10 11 131/2 16 19Thickness of Flange (min)1 – – 7/16
1/29/16
5/811/16
3/413/16
15/1615/16 1 11/8 13/16 11/4
Diameter of Bolt Circle – – 31/8 31/2 37/8 43/4 51/2 6 7 71/2 81/2 91/2 113/4 141/4 17Number of Bolts – – 4 4 4 4 4 4 8 8 8 8 8 12 12Diameter of Bolts – – 1/2
1/21/2
5/85/8
5/85/8
5/83/4
3/43/4
7/87/8
1 125 lb flanges have plain faces.
250 lb CAST IRON – ANSIDiameter of Flange – – 47/8 51/4 61/8 61/2 71/2 81/4 9 10 11 121/2 15 171/2 201/2
Thickness of Flange (min)2 – – 11/163/4
13/167/8 1 11/8 13/16 11/4 13/8 17/16 15/8 17/8 2
Diameter of Raised Face – – 211/16 31/16 39/16 43/16 415/16 511/16 65/16 615/16 85/16 911/16 1115/16 141/16 167/16
Diameter of Bolt Circle – – 31/2 37/8 41/2 5 57/8 65/8 71/4 77/8 91/4 105/8 13 151/4 173/4
Number of Bolts – – 4 4 4 8 8 8 8 8 8 12 12 16 16Diameter of Bolts – – 5/8
5/83/4
5/83/4
3/43/4
3/43/4
3/47/8 1 11/8
2 250 lb flanges have a 1/16” raised face which is included in the flange thickness dimensions.
150 lb BRONZE – ANSIDiameter of Flange 31/2 37/8 41/4 45/8 5 6 7 71/2 81/2 9 10 11 131/2 16 19Thickness of Flange (min)3 5/16
11/323/8
13/327/16
1/29/16
5/811/16
11/163/4
13/1615/16 1 11/16
Diameter of Bolt Circle 23/8 23/4 31/8 31/2 37/8 43/4 51/2 6 7 71/2 81/2 91/2 113/4 141/4 17Number of Bolts 4 4 4 4 4 4 4 4 8 8 8 8 8 12 12Diameter of Bolts 1/2
1/21/2
1/21/2
5/85/8
5/85/8
5/83/4
3/43/4
7/87/8
3 150 lb bronze flanges have plain faces with two concentric gasket-retaining grooves between the port and the bolt holes.
300 lb BRONZE – ANSIDiameter of Flange 33/4 45/8 47/8 51/4 61/8 61/2 71/2 81/4 9 10 11 121/2 15 – –Thickness of Flange (min)4 1/2
17/3219/32
5/811/16
3/413/16
29/3231/32 11/16 11/8 13/16 13/8 – –
Diameter of Bolt Circle 25/8 31/4 31/2 37/8 41/2 5 57/8 65/8 71/4 77/8 91/4 105/8 13 – –Number of Bolts 4 4 4 4 4 8 8 8 8 8 8 12 12 – –Diameter of Bolts 1/2
5/85/8
5/83/4
5/83/4
3/43/4
3/43/4
3/47/8 – –
4 300 lb bronze flanges have plain faces with two concentric gasket-retaining grooves between the port and the bolt holes.
150 lb STEEL – ANSIDiameter of Flange 31/2 37/8 41/4 45/8 5 6 7 71/2 81/2 9 10 11 131/2 16 19Thickness of Flange (min)5 – – 7/16
1/29/16
5/811/16
3/413/16
15/1615/16 1 11/8 13/16 11/4
Diameter of Raised Face 13/8 111/16 2 21/2 27/8 35/8 41/8 5 51/2 63/16 75/16 81/2 105/8 123/4 15Diameter of Bolt Circle 23/8 23/4 31/8 31/2 37/8 43/4 51/2 6 7 71/2 81/2 91/2 113/4 141/4 17Number of Bolts 4 4 4 4 4 4 4 4 8 8 8 8 8 12 12Diameter of Bolts 1/2
1/21/2
1/21/2
5/85/8
5/85/8
5/83/4
3/43/4
7/87/8
5 150 lb steel flanges have a 1/16”raised face which is included in the flange thickness dimensions.
300 lb STEEL – ANSIDiameter of Flange 33/4 45/8 47/8 51/4 61/8 61/2 71/2 81/4 9 10 11 121/2 15 171/2 201/2
Thickness of Flange (min)6 – – 11/163/4
13/167/8 1 11/8 13/16 11/4 13/8 17/16 15/8 17/8 2
Diameter of Raised Face 13/8 111/16 2 21/2 2-7/8 35/8 41/8 5 51/2 63/16 75/16 81/2 105/8 123/4 15Diameter of Bolt Circle 25/8 31/4 31/2 37/8 41/2 5 57/8 65/8 71/4 77/8 91/4 105/8 13 151/4 173/4
Number of Bolts 4 4 4 4 4 8 8 8 8 8 8 12 12 16 16Diameter of Bolts 1/2
5/85/8
5/83/4
5/83/4
3/43/4
3/43/4
3/47/8 1 11/8
6 300 lb steel flanges have a 1/16” raised face which is included in the flange thickness dimensions.
400 lb STEEL – ANSIDiameter of Flange 33/4 45/8 47/8 51/4 61/8 61/2 71/2 81/4 9 10 11 121/2 15 171/2 201/2
Thickness of Flange (min)7 9/165/8
11/1613/16
7/8 1 11/8 11/4 13/8 13/8 11/2 15/8 17/8 21/8 21/4
Diameter of Raised Face 13/8 111/16 2 21/2 27/8 35/8 41/8 5 51/2 63/16 75/16 81/2 105/8 123/4 15Diameter of Bolt Circle 25/8 31/4 31/2 37/8 41/2 5 57/8 65/8 71/4 77/8 91/4 105/8 13 151/4 173/4
Number of Bolts 4 4 4 4 4 8 8 8 8 8 8 12 12 16 16Diameter of Bolts 1/2
5/85/8
5/83/4
5/83/4
3/47/8
7/87/8
7/8 1 11/8 11/4
7 400 lb steel flanges have a 1/4” raised face which is NOT included in the flange thickness dimensions.
600 lb STEEL – ANSIDiameter of Flange 33/4 45/8 47/8 51/4 61/8 61/2 71/2 81/4 9 103/4 13 14 161/2 20 22Thickness of Flange (min)8 9/16
5/811/16 13/16
7/8 1 11/8 11/4 13/8 11/2 13/4 17/8 23/16 21/2 25/8
Diameter of Raised Face 13/8 111/16 2 21/2 27/8 35/8 41/8 5 51/2 63/16 75/16 81/2 105/8 123/4 15Diameter ofBolt Circle 25/8 31/4 31/2 37/8 41/2 5 57/8 65/8 71/4 81/2 101/2 111/2 133/4 17 191/4
Number of Bolts 4 4 4 4 4 8 8 8 8 8 8 12 12 16 20Diameter of Bolts 1/2
5/85/8
5/83/4
5/83/4
3/47/8
7/8 1 1 11/8 11/4 11/4
8 600 lb steel flanges have a 1/4” raised face which is NOT included in the flange thickness dimensions.
81
SYSTEMDESIGN
Pipe Dimensions
Table 38: Schedule 40 Pipe DimensionsLength of Pipe
Diameters Transverse Areas per Sq. Foot of NumberNominal External Internal Cubic Feet Weight Threads
Size External Internal Thickness External Internal Metal Surface Surface per Foot per Foot per InchInches Inches Inches Inches Sq. Ins. Sq. Ins. Sq. Ins. Feet Feet of Pipe Pounds of Screw
1/8 .405 .269 .068 .129 .057 .072 9.431 14.199 .00039 .244 271/4 .540 .364 .088 .229 .104 .125 7.073 10.493 .00072 .424 183/8 .675 .493 .091 .358 .191 .167 5.658 7.747 .00133 .567 181/2 .840 .622 .109 .554 .304 .250 4.547 6.141 .00211 .850 143/4 1.050 .824 .113 .866 .533 .333 3.637 4.635 .00370 1.130 141 1.315 1.049 .133 1.358 .864 .494 2.904 3.641 .00600 1.678 111/2
11/4 1.660 1.380 .140 2.164 1.495 .669 2.301 2.767 .01039 2.272 111/2
11/2 1.900 1.610 .145 2.835 2.036 .799 2.010 2.372 .01414 2.717 111/2
2 2.375 2.067 .154 4.430 3.355 1.075 1.608 1.847 .02330 3.652 111/2
21/2 2.875 2.469 .203 6.492 4.788 1.704 1.328 1.547 .03325 5.793 83 3.500 3.068 .216 9.621 7.393 2.228 1.091 1.245 .05134 7.575 8
31/2 4.000 3.548 .226 12.56 9.886 2.680 .954 1.076 .06866 9.109 84 4.500 4.026 .237 15.90 12.73 3.174 .848 .948 .08840 10.790 85 5.563 5.047 .258 24.30 20.00 4.300 .686 .756 .1389 14.61 86 6.625 6.065 .280 34.47 28.89 5.581 .576 .629 .2006 18.97 88 8.625 7.981 .322 58.42 50.02 8.399 .442 .478 .3552 28.55 810 10.750 10.020 .365 90.76 78.85 11.90 .355 .381 .5476 40.48 812 12.750 11.938 .406 127.64 111.9 15.74 .299 .318 .7763 53.614 14.000 13.125 .437 153.94 135.3 18.64 .272 .280 .9354 63.016 16.000 15.000 .500 201.05 176.7 24.35 .238 .254 1.223 78.018 18.000 16.874 .563 254.85 224.0 30.85 .212 .226 1.555 105.020 20.000 18.814 .593 314.15 278.0 36.15 .191 .203 1.926 123.024 24.000 22.626 .687 452.40 402.1 50.30 .159 .169 2.793 171.0
Table 39: Schedule 80 Pipe DimensionsLength of Pipe
Diameters Transverse Areas per Sq. Foot of NumberNominal External Internal Cubic Feet Weight Threads
Size External Internal Thickness External Internal Metal Surface Surface per Foot per Foot per InchInches Inches Inches Inches Sq. Ins. Sq. Ins. Sq. Ins. Feet Feet of Pipe Pounds of Screw
1/8 .405 .215 .095 .129 .036 .093 9.431 17.750 .00025 .314 271/4 .540 .302 .119 .229 .072 .157 7.073 12.650 .00050 .535 183/8 .675 .423 .126 .358 .141 .217 5.658 9.030 .00098 .738 181/2 .840 .546 .147 .554 .234 .320 4.547 7.000 .00163 1.00 143/4 1.050 .742 1.54 .866 .433 .433 3.637 5.15 .00300 1.47 141 1.315 .957 .179 1.358 .719 .639 2.904 3.995 .00500 2.17 111/2
11/4 1.660 1.278 .191 2.164 1.283 .881 2.301 2.990 .00891 3.00 111/2
11/2 1.900 1.500 .200 2.835 1.767 1.068 2.010 2.542 .01227 3.65 111/2
2 2.375 1.939 .218 4.430 2.953 1.477 1.608 1.970 .02051 5.02 111/2
21/2 2.875 2.323 .276 6.492 4.238 2.254 1.328 1.645 .02943 7.66 83 3.500 2.900 .300 9.621 6.605 3.016 1.091 1.317 .04587 10.3 8
31/2 4.000 3.364 .318 12.56 8.888 3.678 .954 1.135 .06172 12.5 84 4.500 3.826 .337 15.90 11.497 4.407 .848 .995 .0798 14.9 85 5.563 4.813 .375 24.30 18.194 6.112 .686 .792 .1263 20.8 86 6.625 5.761 .432 34.47 26.067 8.300 .576 .673 .1810 28.6 88 8.625 7.625 .500 58.42 45.663 12.76 .442 .501 .3171 43.4 810 10.750 9.564 .593 90.76 71.84 18.92 .355 .400 .4989 64.4 812 12.750 11.376 .687 127.64 101.64 26.00 .299 .336 .7058 88.614 14.000 12.500 .750 153.94 122.72 31.22 .272 .306 .8522 107.016 16.000 14.314 .843 201.05 160.92 40.13 .238 .263 1.117 137.018 18.000 16.126 .937 254.85 204.24 50.61 .212 .237 1.418 171.020 20.000 17.938 1.031 314.15 252.72 61.43 .191 .208 1.755 209.024 24.000 21.564 1.218 452.40 365.22 87.18 .159 .177 2.536 297.0
82
HOOK-UPAPPLICATION
DIAGRAMS
Section 2
HOOK-UP DIAGRAMS
84
Boiler Steam Headers provide collect-ing vessels for the steam flowing fromone or more boilers, and distribute it toas many mains as are needed to sup-ply the plant. Often the flow may be ineither direction along the headerdepending on which boilers and whichsupply lines are being used. Selectingthe ideal location for the drip point isthus complicated. It is recommendedto make the header of such an
Figure II-1Boiler Steam Header
To Plant
Spira-tecLoss
Detector
Thermo-Dynamic
Steam Trapwith Integral
Strainer
Figure II-2Draining End of Low Pressure Steam Main
FromBoiler
Spira-tecLoss
Detector
Thermo-Dynamic
Steam Trapwith Integral
Strainer
Float &ThermostaticSteam Trap
Spira-tecLoss
Detector
Strainer
CondensateReturn
In the case of low pressure mains,the use of Float and Thermostatictraps is recommended for the dripstations. The introduction of F & Ttraps with steel bodies, third gen-eration capsule type or bimetallicair vents, and operating mecha-nisms suitable for pressures up to465 psi, means that F & T trapscan also be used on properlydrained lines where waterhammerdoes not occur, even at pressureswhich would formerly have exclud-ed them. An auxiliary air vent isrecommended for the end of allmains where the system is startedup automatically.
LP Steam Main
increased diameter as to drop thesteam velocity through it to a low valueeven with maximum flow in eitherdirection. The header can then act alsoas a separator, and generously sizedsteam traps can be fitted at each end.The boiler header and the separator,which should be fitted in the steamtake off from modern high perfor-mance packaged boilers, maysometimes have to cope with carry-
over from the boiler. These two loca-tions form the exception to the generalrule that mains drip points rarely needa steam trap as large as the 1/2" sizeand can usually be fitted with 1/2" LowCapacity traps. Instead, traps in 3/4"and even 1" sizes are often used. Thepotential for steam losses when theselarger traps eventually become worn isincreased, and the use of Spira-tecsteam trap monitors is especially valid.
SupervisedStart-up
Valve
SupervisedStart-up
Valve
85
HOOK-UP DIAGRAMS
Drip points along the run of the steamlines, and at the bottom of any risers,should incorporate large diametercollecting pockets. Equal tees areuseful in sizes up through 6" andlarger size pipes can have pockets 2or 3 sizes smaller than the main butnot less than 6". The terminal pointsof the mains should have automaticair vents, and equal tees again pro-vide convenient collecting pockets forboth condensate and air wheninstalled as shown.
Figure II-3Draining and Air Venting Steam Lines
InvertedBucket
Steam Trapwith Integral
Strainer
Spira-tecLoss
Detector
BalancedPressure
ThermostaticAir Vent
Condensate Main
Thermo-Dynamic
Steam Trapwith Integral
Strainer
Spira-tecLoss Detector
Figure II-4Draining Expansion Loops
Condensate Return
Thermo-Dynamic
Steam Trapwith Integral
Strainer
Thermo-DynamicSteamTrap
Spira-tecLoss
Detector
Spira-tecLoss
Detector
Expansion loops are often fitted inthe vertical plane, with the loop eitherbelow or above the line. When belowthe line, condensate can collect in thebottom of the loop. Above the line, itwill collect just in front of the loop, atthe foot of the riser. Drainage pointsare necessary in each case, asshown.
SupervisedStart-up
Valve
SupervisedStart-up
Valve
Strainer
86
HOOK-UP DIAGRAMS
Both HP and LP mains often must bedrained to a condensate return line atthe same elevation as the steam line.The best location for the traps is thenbelow the steam line, with a riserafter the trap to the top of the returnline.aaaaaaaaaaaaaaaa aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaFigure II-5
Draining Steam Mains to Return Main at Same Level
Spira-tecLoss
Detector
Thermo-DynamicSteam Trap withIntegral Strainer
Connector
Float &ThermostaticSteam Trap
Strainer
Spira-tecLoss
Detector
CondensateMainHP
MainLP
Main
For supervised startup of steammains, a manual bypass is fitted sothat condensate can be drained bygravity while the line pressure is toolow for it to be handled by the trap atan adequate rate. If a second trap isfitted in the bypass line, a similarhookup is obtained which is suitablefor automatic startup.
Figure II-6Trapping Hook-up for Start-up of Steam Main
Often the normal trap discharges to areturn line at higher elevation. Thestartup trap must always dischargeby gravity so here it is separated fromthe “normal running” trap. AThermoton is used so that it will closeautomatically when the condensatetemperature shows that warm up ofthe main is nearing completion.
Figure II-7Hook-up with Condensate Return Line at High Level
Thermo-DynamicSteam Trapwith Integral
Strainer
Spira-tecLoss
Detector
Thermo-Dynamic SteamTrap with Integral Strainer
Spira-tecLoss
Detector
Thermo-DynamicSteam Trapwith Integral
Strainer
Spira-tecLoss
Detector
Liquid ExpansionSteam Trap
Drain
CondensateReturn
CheckValve
CheckValve
SupervisedStart-up
Valve
CheckValve
SupervisedStart-up
Valve
87
HOOK-UP DIAGRAMS
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaIn some cases, the existence of other service or processlines alongside the stream main is combined with theneed to lift the condensate from the drip point to higherlevel. Without the loop seal, clearance of condensatefrom length L and replacement with steam means that forappreciable times steam passes up length H and holdsthe trap closed, although condensate may be collecting inthe pocket. The arrangement shown minimizes this prob-lem and gives most consistent performance of the trap.
Thermo-Dynamic
Steam Trapwith Integral
Strainer
Spira-tecLoss
Detector
Figure II-8Draining Steam Main where Trapmust be at Higher Level
SteamMain
GenerousCollecting
Loop Seal(where “L”
exceeds “H”)
CondensateMain
L
H
Figure II-9Condensate Drainage to Reinforced Plastic Return Line, with Overheat Protection
Steam Main
CondensateReturn Pipe
CoolingChamber
Diffuser
Spira-tecLoss
Detector
Main DripSteam Trap
HighTemperature
Drain
T44 Temperature Control(set to open at temperature
limit of pipe)On some extended sites,steam distribution is under-ground and drip points areinside “steam pits”. Steammain drip traps should dis-charge into gravity returnsystems, but at times it maybe necessary to connect themdirectly to a pumped conden-sate line. To avoid failure ofplastic or fiberglass pipingcaused by high temperaturefrom steam leakage wheneventually the trap becomesworn, a cooling chamber andcontrol as shown can be used.If the temperature of the con-densate leaving the chamberever reaches the safe limit, thecontrol valve opens.Condensate is dischargedabove grade, where it can beseen, until its temperature fallsagain below the limiting value.
CheckValve
CheckValve
SupervisedStart-up
Valve
Set downabout 2"
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa88
HOOK-UP DIAGRAMS
A. TD traps on high temperature tracingapplication where tracer line must bedrained clear of condensate.
B. TSS300 traps on low temperature tracingwhere product temperature is below 150˚Fand some of sensible heat in condensatemay be utilized to improve efficiency.
Figure II-10 Typical Steam Tracer Trapping Arrangements
Thermo-Dynamic
Steam Trapwith Integral
Strainer
BalancedPressure
ThermostaticSteam Trap
Spira-tecLoss
Detector
Spira-tecLoss
DetectorStrainer
TracerTracer
Product Line Product Line
Insulation
A B
Steam will automatically shut downas ambient temperatures rise aboveproduct solidification temperature.Select self acting temperature controlfor number of tracer lines.
Figure II-11Steam Tracing System withPreassembled Manifolds
AmbientSensing
TemperatureControl
Strainer
SteamMain
SteamDistribution
Manifold
CondensateCollectionManifold
Steam Trap Stationwith Test Valves
Steam Trap Stationwith Test Valves
Steam toTracers
Condensatefrom Tracers
To Drain
ToCondensate
Return
To drain during supervisedstartup or during shutdown
Steam is uniformly distributed to tracers by forged steel manifold with integral pis-ton valves. After supplying heat to tracer lines, condensate is collected infabricated manifold preassembled with steam trap stations. Three-way test valvesallow for startup purging, checking of lines for blockage, isolation of trap for main-tenance, and visual testing of steam trap operation. Condensate manifold has aninternal siphon pipe to reduce waterhammer and provide freeze protection.
aa89
HOOK-UP DIAGRAMS
Spira-tecLoss
Detector
StrainerSelect inlet piping for reasonablevelocity and expand downstreamfor equal flow rate.
Figure II-12Typical Pressure Reducing Valve Station
Float &ThermostaticSteam Trap
Strainer
SafetyValve
SteamSupply
Pilot OperatedPressure Control Valve
Figure II-13Parallel Operation of Pressure Reducing Valvesaaaa
Set lead valve 2 psi above desiredset pressure and set lag valve 2 psibelow desired set pressure.
Spira-tecLoss
Detector
Strainer
SafetyValve
SteamSupply
Pilot OperatedPressure Control Valve
Pilot OperatedPressure Control Valve
Strainer
Strainer
Float &ThermostaticSteam Trap
MoistureSeparator
PressureSensing Line
PressureSensing Line
CheckValve
DripPan
Elbow
MoistureSeparator
ReducedSteam
Pressure
CheckValve
DripPan
Elbow
ReducedSteam
Pressure
aaaa90
HOOK-UP DIAGRAMS
Figure II-14Series Pressure Reducing Valve Station for High Turndown Rations
Note: Intermediate pressure takeoff requires an additional safety valve.
Spira-tecLoss
Detector
Strainer
SafetyValve
SteamSupply
Pilot OperatedPressure Control Valve
Pilot OperatedPressure Control Valve
Strainer Strainer
Float &ThermostaticSteam Trap
MoistureSeparator
PressureSensing
Line
Spira-tecLoss
Detector
Strainer
Float &ThermostaticSteam Trap
PressureSensing
Line
Figure II-15Hook-up for Remote Operation of 25 PRM Pressure Reducing Valve
Float &ThermostaticSteam Trap
Float &ThermostaticSteam Trap
Float &ThermostaticSteam Trap
Strainer
Strainer
SafetyValve
SteamSupply
MoistureSeparator
MainControl Valve
RemotePressure
Pilot
Limit pilot to 15 ft. drop below mainvalve and drain all supply tubing. Ifpilot is mounted above main valve,pilot line drip traps can be eliminated.For longer distance an air loadedpilot should be used.
CheckValve
DripPan
Elbow
ReducedSteam
Pressure
CheckValve
DripPan
Elbow
ReducedSteam
Pressure
CheckValve
CheckValve
CheckValve
Noise Diffuser(if required)
5/16" CopperTubing or 1/4" Pipe
1/2" Pipe
91
HOOK-UP DIAGRAMSFigure II-17
Low Capacity Pressure Reducing Station
Figure II-16Installation of Pressure Reducing Valve in “Tight Spaces”
PressureSensing LinePitch Down
Spira-tecLoss
Detector
Strainer
Thermo-DynamicSteam Trap
SafetyValve
Strainer
DirectOperatedPressureReducing
Valve
ReducedSteam
Pressure
10 PipeDiametersMinimum
Strainer
Strainer
Strainer
Float &ThermostaticSteam Trap
SteamSupply
MoistureSeparator
Float &ThermostaticSteam Trap
Float &ThermostaticSteam Trap
Strainer
SafetyValve
DripPan
Elbow
ReducedSteam
Pressure
CheckValve
CheckValve
CheckValve
Noise Diffuser(if required)
Pilot OperatedPressureControlValve
Ten PipeDiameters
DripPan
Elbow
92
HOOK-UP DIAGRAMS
Figure II-1825 BP Back Pressure Controls used to Restrict Supply to Low Priority Uses at Times of Overload
Steam toNon-essential
ServiceStrainer
Thermo-DynamicSteam Trapwith Integral
Strainer
Steam Supplyfrom Boiler
Strainer
Pilot OperatedPressure Reducingand Back Pressure
Valve
Steam toPriority Use
10 Pipe DiametersMinimum fromValve Outlet
At times of peak draw off, boilers which have sufficientcapacity to meet average load conditions may becomeoverloaded. This can cause carryover and priming, or evenlockout of boilers on low water. The pressure in the steamlines falls and essential services may be interrupted. Theuse of back pressure controls in the supplies to non-essen-tial loads allows these to be automatically shut down, inorder of priority, at peak load times while maintaining supplyto more important loads.
Spira-tecLoss
Detector
Header
Pilot OperatedBack Pressure Valve
Figure II-19Reducing Steam Pressure Using 25PA Control Valve with Remote Air Valve
Depending on pilot selected, reducedsteam pressure will be approximately 1:1,4:1 or 6:1 times the air loading pressuresent to the pilot.
SafetyValve
Spira-tecLoss
Detector
Strainer
Strainer
Float &ThermostaticSteam Trap
Filter/Regulator
SteamSupply
MoistureSeparator
AirSupply
PressureSensing LinePitch Down
Air Loaded
Pilot
Air OperatedControl Valve
DripPan
Elbow
ReducedSteam
Pressure
CheckValve
DripPan
Elbow
SafetyValve
Reduced SteamPressure to
Non-essential Service
93
HOOK-UP DIAGRAMS
Figure II-20Typical Pneumatic Single StagePressure Reducing Valve Station
Figure II-22Hook-up for 25 TRM Temperature Control Remotely Mounted (within 15 ft. of Main Valve)
StrainerSteamSupply
MoistureSeparator Main
Control Valve
Float &ThermostaticSteam Trap
Strainer
Float &ThermostaticSteam Trap
RegulatedSteam toProcess
Sensor
1/2" Pipe
Figure II-21Pneumatic Temperature Control of Heat Exchanger
StrainerSteamSupply
MoistureSeparator
Float &ThermostaticSteam Trap
Strainer
SafetyValve
VacuumBreaker
Strainer
MoistureSeparator
Float &ThermostaticSteam Trap
Strainer
Spira-tecLoss
Detector
Float &ThermostaticSteam Trap
Strainer
Spira-tecLoss
Detector
SteamSupply
DripPan
Elbow
ReducedSteam
Pressure
Noise Diffuser(if required)
SupplyAir
ControlSignal
PneumaticControlValve
CheckValve
Controller
Controller PneumaticControl Valve
with Positioner
Supply Air
Control Signal
Supply Air
Heat Exchanger
CheckValve
CheckValve
Sensor
Liquid in/out
CheckValve
CheckValve
RemoteTemp.Pilot
5/16" Copper Tubingor 1/4" Pipe
94
HOOK-UP DIAGRAMS
Figure II-23Pressure Reducing Valve for Pressure Powered Pump Motive Steam
Figure II-24Heat-up, Pressuring and Shutdown of Steam Mainsusing On/Off Control Valves and Programmer
Thermo-DynamicSteam Trapwith Integral
Strainer
Pilot OperatedOn/Off Control Valve
(for heatup only)
Spira-tecLoss
Detector
Strainer
SteamSupply
Strainer
Thermo-DynamicSteam Trapwith Integral
Strainer
Spira-tecLoss
Detector
Pilot OperatedOn/Off Control Valve(for maximum flow)
SteamMain
AutomaticTime
Switch
Power
Thermo-Dynamic
Steam Trap
SteamSupply
Strainer
Strainer
SafetyValve
DripPan
Elbow
MotiveSteam
to Pump
Direct or Pilot OperatedPressure Reducing Valve
Pressure Surge Reservoir1-1/2" or 2" diameter, 6’ longwith eccentric fittings on ends
Steam toSystem
Hand Valveto adjustflow rate
AdjustablePressurestat
(with N.O. Switch)
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HOOK-UP DIAGRAMS
Figure II-25Complete CondensateDrainage from Air HeaterCoil under “Stall” withCombination Pump/Trapin a Closed Loop System
When the steam pressure within thecoil is high enough to push conden-sate through the steam trap, againstany back pressure from a lift to high-er level or into a pressurized line, thepump is inoperative. If the action ofthe temperature control lowers thecoil pressure sufficiently, the conden-sate flow stalls. Water backing up intothe PPP body brings it into operationand the pump uses motive steam topush the condensate through the trapto the return line.At the end of each discharge stroke,the motive steam in the pump body isexhausted through a balance line tothe top of the liquid reservoir. A ther-mostatic air vent on the balance linevents air under startup conditions,even if the pump/trap is fully floodedwith condensate at this time.
Figure II-25AProcess Condensate Removal Module
A preassembled modular pumping systemprovides a sole source solution for airheater coil applications.
Float &ThermostaticSteam Trap
Direct orPilot OperatedTemperature
Control
Strainer
SteamSupply
MotiveSteamSupply
PressurePowered
Pump
MoistureSeparator
Thermo-Dynamic
Steam Trap
Reservoir
CondensateReturn
HeatedAir
Outlet
TemperatureControlSensor
ThermostaticAir Vent
AirInlet
CheckValve
Float &ThermostaticSteam Trap
Strainer
Spira-tecLoss Detector
Strainer
Coil
Drain toSafePlace
See Fig. II-25A for thepreassembled
Process CondensateRemoval Module
Steam Trap Station
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HOOK-UP DIAGRAMS
Figure II-26Controlling and Draining Preheat andReheat Coils in Vented CondensateSystem with Freeze Resistant Pipingfor Makeup Air
Each coil must be individually drainedto provide for proper and accuratecontrol. Strainers are not fitted in frontof the traps in case they become par-tially blocked. Freeze resistant coilsmust have vacuum breaker, trapssized for full load with 1/2 psi differen-tial and unobstructed piping to anatmospheric return system.
Float &ThermostaticSteam Trap
Pilot OperatedTemperatureControl Valve
Spira-tecLoss
DetectorMotiveSupply
PressurePowered
Pump
Thermo-Dynamic
Steam Trapwith Integral
Strainer
Vented Receiver CondensateReturn
TemperatureControlSensor
ThermostaticAir Vent
Pilot OperatedTemperatureControl Valve
ThermostaticAir Vent
Float &ThermostaticSteam Trap
Spira-tecLoss
Detector
Strainer
Float &ThermostaticSteam Trap
Strainer
Spira-tecLoss
Detector
TemperatureControlSensorHeated
AirOutdoor
Air
VacuumBreaker
SteamSupply
SteamSupply
Thermo-Dynamic
Steam Trapwith Integral
Strainer
VacuumBreaker
LiquidExpansionSteam Trap
LiquidExpansionSteam Trap
Drain toSafePlaceDrain to
SafePlace
97
HOOK-UP DIAGRAMS
Figure II-27Freeze Proof Piping ofLarge Vertical Air Heater Coil toAtmospheric Condensate Return System
* To preclude accidental closing, these valvesshould be chain locked in open position, orthey may be omitted.
Figure II-28High Pressure SteamCoils Trapped forFlash Recovery to LPSteam System
Float &ThermostaticSteam Trap
Pilot OperatedTemperatureControl Valve
MotiveSupply
PressurePowered
Pump
Thermo-Dynamic
Steam Trapwith Integral
Strainer
CondensateReturn
TemperatureSensor
ThermostaticAir Vent
Float &ThermostaticSteam Trap
Strainer
Float &ThermostaticSteam Trap
Strainer
Spira-tecLoss
Detector
Thermo-Dynamic
Steam Trap
PackagedPressurePowered
Pump Unit
Strainer
Spira-tecLoss
Detector
VerticalAir Coil
SteamSupply
Pilot OperatedBack PressureControl Valve
Condensate ReturnPitch Down
MoistureSeparator
Float &ThermostaticSteam Trap
Strainer
FlashRecovery
Vessel
Float &ThermostaticSteam Trap
Strainer
Pilot OperatedPressure
Control Valve
SafetyValve
SafetyValve
VacuumBreaker
VacuumBreaker
**
Vent
SteamSupply
Vent
DripPan
Elbow
CheckValve
To CondensateReturn
DripPan
Elbow
AirVent
AirHeating
Coils
Low Pressure Steam
Drain toSafePlace
98
HOOK-UP DIAGRAMS
Figure II-29Storage Cylinder withHigh Limit Protection
Fail safe protection against excess temperatures is provided by a separate con-trol valve, normally latched wide open. If the 130 self-acting control systemdetects a temperature overrun, or if the control system itself is damaged, a pow-erful spring is released in the HL10 unit and the high limit valve is driven closed.A switch is available as an extra to provide electrical warning that the device hasbeen actuated.
Figure II-30Condensate Drainage from Unit Heater
TemperatureControlSensor
Spira-tecLoss
Detector
Valve
MoistureSeparator
Float &ThermostaticSteam Trap
Float &ThermostaticSteam Trap
Strainer
Self ActingTemperature
Control
Spira-tecLoss
Detector
Strainer
SteamSupply
Strainer
High Limit130 Sensor
HL10OverheatProtection
Hot Flow
Circ.Return
ColdSupply
StorageTank
Float &ThermostaticSteam Trap
Spira-tecLoss
Detector
Strainer
SteamSupply
UnitHeater
Drain condensateby gravity where
possible—especially to vac.
return system
VacuumBreaker
CheckValve
CheckValve
ToCondensate
Return
ToOverhead
Return
Liquid ExpansionSteam Trap
To Drain
AlternateLocation
Note: The Liquid ExpansionSteam Trap will automatical-ly drain unit heater duringperiods of shutdown whichwill prevent damage due tocorrosion.
Liquid ExpansionSteam Trap
99
HOOK-UP DIAGRAMS
Figure II-31Temperature Control of Warm-up and RunningLoads at Storage Tank
Figure II-32Draining Heat Exchanger under Constant “Stall”Condition with Pumping Trap in Closed Loop Systemaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa aaaaaaaaaaaaaaaaaaaaaaaaaaa
A control valve suitably sized to supply the start upload on a tank is often very much oversized for therunning load, and this oversizing can lead to erraticcontrol. In such cases, a large control valve may beused to meet the warm up load, arranged to closeat a temperature perhaps 2° below the final controltemperature. The smaller control valve meets therunning load, and the supply is supplementedthrough the start up valve, only when the capacityof the smaller valve is exceeded.
Draining L.P. Heat Exchanger toOverhead Return. Pressure at pumpoutlet P2 always exceeds supplypressure P1 to Heat Exchanger.Completely immerse control sensorwithout well, right at hot outflow.To prevent overheating, the sensormust not see a “dead” flow.
LowTemperature
Sensor
Spira-tecLoss
Detector
MoistureSeparator
ThermostaticSteam Trap Strainer
RunningTemperature
ControlValve
StrainerSteamSupply
CondensateReturn
StorageTank
Spira-tecLoss
Detector
StrainerFloat &ThermostaticSteam Trap
Warm UpTemperature
ControlValve
RunTemperature
Sensor
Thermo-static
Air Vent
MoistureSeparator
Pilot OperatedTemperatureControl Valve
Strainer
SteamSupply
Heat Exchanger
Spira-tecLoss
Detector
Strainer
PressurePowered
Pump
Thermo-DynamicSteamTrap
Float &ThermostaticSteam Trap
Hot
Cold
MotiveSteamSupply
Reservoir
Sensor
PressurizedReturnSystem
CheckValve
Strainer
Check Valve
P1
P2
Drain toSafePlace
100
HOOK-UP DIAGRAMS
Figure II-33Combined Pressureand TemperatureControl of HeatExchanger
When the pressure of the steam supply is higher than theheat exchanger can withstand, or is at a higher valuethan necessary to allow for fouling of the heat exchangesurfaces, a pressure reducing valve is required. This caneconomically be combined with a temperature control byusing pressure sensing and temperature sensing pilotsto operate a common main valve. Sensor bulb must befully immersed right at hot outflow and use of a separa-ble well should be avoided.
Figure II-34Draining Small Heat Exchanger andOther Loads to Pressure Powered Pump
Arrangement of Small Steam/Liquid HeatExchanger where steam space pressure may fallbelow back pressure and trap has gravity drain.Note: Head “H” must be enough to give trapcapacity needed when steam space pressurefalls to zero.
ThermostaticAir Vent
MoistureSeparator
Pilot OperatedPressure/Temperature
Control Valve
Heat Exchanger
Spira-tecLoss
Detector
StrainerFloat &
ThermostaticSteam Trap
ColdWaterSupply
Sensor
Spira-tecLoss
Detector
Float &ThermostaticSteam Trap
SafetyValve
Strainer
GravityReturn
SteamSupply
StrainerFloat &
ThermostaticSteam Trap
SteamSupply
Spira-tecLoss Detector
StrainerFloat &
ThermostaticSteam Trap
VacuumBreaker
Temp.ControlSensor
Self ActingTemperature
ControlMoistureSeparator
Heat Exchanger
PressurePowered
Pump
ReceiverStrainer
Thermo-Dynamic
Steam Trap
CondensateReturn
Multiple LoadsConnected to
Vented Receiver
Spira-tecLoss Detector
VacuumBreaker
Drip PanElbow
LiquidIn/OutFlow
Strainer
H
See Fig. II-34A forthe preassembled
CondensateRecovery Module
Drain toSafePlace
Steam Trap Station
Steam Trap Station
Note: scensor mustnot see a“dead” flow.
Note: scensor mustnot see a“dead” flow.
101
HOOK-UP DIAGRAMSaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa a aaaaaaaaaaaaaa Figure II-35
Draining Equipment to PressurizedReturn with Closed LoopPump/Trap Drainage System
P1 exceeds P2 except when partialloads “stall” the exchanger. With thishook up, the reservoir pipe is alwaysconnected to, and at the same pres-sure as, the heat exchanger steamspace. Condensate drains to it freely.The pump body is connected in thesame way, except during the dischargestroke when the inlet check valve andthe exhaust valve are closed. After dis-charge, the residual steam in the pumpbody is exhausted to the heater and itslatent heat can then be recovered.Steam trap functions at full load andThermoton drains at shutdown.
SteamSupply
Spira-tecLoss Detector
Strainer
Float &ThermostaticSteam Trap
PneumaticControlValve
MoistureSeparator
Heat Exchanger
PressurePowered
Pump
Reservoir Pipe
Drain
Thermo-Dynamic
Steam Trap
Elevated orPressurizedReturn
Strainer
Strainer
Spira-tecLoss Detector
Float &ThermostaticSteam Trap
HotFlow
CoolReturn
MotiveSteam Supply
Thermo-static
Air Vent
P1
P2
See Fig. II-35A forthe preassembled
Process CondensateRemoval Module
Figure II-35AProcess Condensate Removal ModuleA preassembled modular will remove condensate from the heat exchanger under all operating conditions.
Figure II-34ACondensate Recovery ModuleA preassembled modular pumping system can be usedto recover and reuse the condensate.
Sensor
Controller
SupplyAir
ControlSignal
Drain toSafePlace
Steam Trap Station
Liquid ExpansionSteam Trap
Note: To prevent overheating, the scensor must not seea “dead” flow.
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HOOK-UP DIAGRAMS
Figure II-36Low Pressure Steam Absorption Chiller
Figure II-37High Pressure Steam Absorption ChilleraaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaFloat &
ThermostaticSteam Trap
PressurePowered
Pump
Reservoir Pipe
Thermo-Dynamic
Steam Trapwith Integral
Strainer
ToCondensate
Return
MotiveSteam Supply
ThermostaticAir Vent
CheckValve
AbsorptionChiller
Steam Supply(15 psig or less)
ToCondensate
Return
MotiveSteam Supply
Absorption Chiller
Steam Supply(normally 45
psig or higher)
Vent
PackagedPressurePowered
Pump
Thermo-DynamicSteam Trapwith Integral
Strainer
Note: Depending on chiller manufacturer, a steam trapmay not be required or it may be supplied with the chiller.Other specialties needed may include a steam pressurereducing valve on the inlet, steam separator with trap,steam safety valve or inlet strainer.
Drain toSafe Place
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HOOK-UP DIAGRAMS
Figure II-38 Automatic Control of BatchProcessor with Electrical Time SequenceProgrammer
Figure II-39Controlling Temperature of Open Tankfor Plating, Dyeing of Process Work
ThermostaticAir Vent
SteamSupply
Spira-tecLoss Detector
Float &ThermostaticSteam Trap
Pilot OperatedPressure/Temperature
Control Valvewith Solenoid
MoistureSeparator
Autoclave
SafetyValve
Strainer
Strainer
Spira-tecLoss
Detector
Float &ThermostaticSteam Trap
ElectricOperator
Spira-tecLoss
Detector
Strainer
Float & ThermostaticSteam Trap
SteamFilter
Power
StrainerFloat &
ThermostaticSteam Trap
Spira-tecLoss
DetectorStrainer
Float &ThermostaticSteam Trap
Spira-tecLoss
Detector
MoistureSeparator
Strainer
PressureSensing LinePitch Down
Strainer
PilotOperated
TemperatureControl Valve
LoopSeal
GravityReturn
DripPan
Elbow
BalancedPressure
ThermostaticSteam Trap
SteamSupply
Drain toSafe Place
SmallBoreRiser
104
HOOK-UP DIAGRAMS
Figure II-40Controlling Platen Press Temperaturewith Pressure Regulator and ElectricProgrammer. Indicating Pilot PermitsFast Temperature Changes
Figure II-41Controlling Temperature of Pressurized Boiler Feed Water Tank
Note: When supply pressure is above 125 psi, install an additionalSpirax Sarco pressure control valve ahead of pressure/temperaturecontrol valve to reduce pressure to 125 psi.
Strainer
Thermo-DynamicSteam Traps withIntegral Strainer
Spira-tecLoss Detector
Strainer
Float &ThermostaticSteam Trap
Spira-tecLoss
Detector
Strainer
Pressure ReducingControl Valvewith Solenoid
SteamSupply
MoistureSeparator
SafetyValve
ElectricOperatorPower
PressureSensing LinePitch Down
Float &ThermostaticSteam Trap
Condensate Return
Strainer
Spira-tecLoss
Detector
Strainer
Pilot OperatedPressure/Temperature
Control Valve
SteamSupply(125 psior less)
MoistureSeparator
SafetyValve
Float &ThermostaticSteam Trap
VacuumBreaker
Pilot OperatedBack PressureControl Valve
PerforatedHeater Tube
Pack HeatCompoundin Bulb Well
Make upWaterSupply
PumpSuction
CondensateReturn
ThermostaticAir Vent
DripPan
Elbow
Drain toSafe Place
105
HOOK-UP DIAGRAMS
Figure II-42Controlling Temperature of Vented Boiler Feed Water Tank
Figure II-43Controlling Temperature of Large Open Tank Heated by Direct Steam Injection
Strainer
Spira-tecLoss
Detector
Strainer
Pilot OperatedTemperatureControl Valve
MoistureSeparator
Float &ThermostaticSteam Trap
VacuumBreaker
SteamInjector
SteamSupply
OpenTank
Provide suitable supportand protection for
capillary tubing andtemperature bulbs
VacuumBreaker
Strainer
CondensateReturn
VentHead
SteamSupply
TemperatureControl Valve
Sensor
To B.F. PumpSuction
Perforated Heater Tube
Make upWater
CondensateReturn
106
HOOK-UP DIAGRAMS
Figure II-44Controlling Temperature of Small Open Tank, Heated by Direct Steam Injection
Figure II-45Controlling Temperature of Water Suppliedto Spray Nozzles of Egg Washing Machine
Strainer
SteamInjector/
Thermoton
VacuumBreaker
Strainer
Spira-tecLoss
Detector
Strainer
Pilot OperatedTemperatureControl Valve
SteamSupply
MoistureSeparator
ColdWaterSupply
Float &ThermostaticSteam Trap
VacuumBreaker
Pack Sensor Well withHeat Conducting
CompoundSteam Injector
CentrifugalPump
Float OperatedC.W. Valve
WarmWaterSupply
to WasherSpray
Nozzles
GravityReturnfrom
Washer
Open Tank
Vent
107
HOOK-UP DIAGRAMS
Figure II-46Controlling Temperature of Greenhouse or Other Similar Buildings
Figure II-47Steam Radiator
Strainer
Spira-tecLoss
DetectorStrainer
Fin-TubeRadiation
SteamSupply
MoistureSeparator
Float &ThermostaticSteam Trap
RoomThermostat
LiquidExpansionSteam Trap
Pilot OperatedOn/Off Control Valve
Return
ThermostaticRadiator
Trap
RadiatorValve
Supply
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HOOK-UP DIAGRAMS
Figure II-48Trapping and Air Venting HospitalSterilizer with Dry Steam Supply
Figure II-49Control and Drainage Hook-up forHospital Blanket and Bedpan Warmer
Strainer
Spira-tecLoss
Detector
Strainer
SteamSupply
MoistureSeparator
Float &ThermostaticSteam Trap
ThermostaticAir Vent
Float &ThermostaticSteam Trap
Float &ThermostaticSteam Trap
ThermostaticAir Vent
Ball Valve
Thermo-Dynamic
Steam Trap
Filter
Spira-tecLoss
Detector
Strainer
Float &ThermostaticSteam Trap
Thermo-Dynamic
Steam Trapwith Integral
Strainer
MoistureSeparator
BalancedPressure
ThermostaticSteam Trap
Spira-tecLoss
Detector
Self ActingTemperature
Control
HeatingCoil
Small size trapis required
Drain toSafe Place
SteamSupply
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HOOK-UP DIAGRAMS
Figure II-50Trapping Small Utensil Sterilizer
Figure II-51Condensate Drainage fromHospital Mattress Disinfector
Strainer
SteamSupply
Balanced PressureThermostaticSteam Trap
Strainer
SteamSupply
Float &ThermostaticSteam Trap
Spira-tecLoss
Detector
Spira-tecLoss
Detector
Strainer Float &ThermostaticSteam Trap
ThermostaticAir Vent
Strainer
Drain toSafe Place
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HOOK-UP DIAGRAMS
Figure II-52Float & Thermostatic TrapFreeze Resistant Hook-up
Float &ThermostaticSteam Trap
Liquid ExpansionSteam Trap
VacuumBreaker
Figure II-53Thermoton Controlling Temperatureof Large Storage TankaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaLiquid
ExpansionSteam Trap
SteamSupply
Strainer
Strainer
Figure II-54Equipment Drained with Permanent Connector Thermo-Dynamic Steam Trapsthat fit into both Horizontal and Vertical Pipework
Floor
Thermo-Dynamic
Steam Trapwith Integral
Strainer
Thermo-Dynamic
Steam Trapwith Integral
StrainerThermo-Dynamic
Steam Trapwith Integral
Strainer
CondensateReturn
Steam Main
StorageTank
111
HOOK-UP DIAGRAMS
Figure II-55Draining and Air VentingFlatwork Ironer
The steam traps are often located atone end for ease of maintenance,with long pipes connecting them tothe drainage points. If steam-lockingis a problem in these long pipes,then a Float / Thermostatic steamtrap with a steam-lock release is thebest selection. The beds should beair vented at points remote from thesteam entry. Steam supply lines toironers should be drained, ideallyusing a separator.
Figure II-56System Units for Condensate Removaland Air Venting of Rotating Cylinders(for surface speeds below 800 FPM)
GravityReturn
StrainerSightGlass with
Check Valve
Steam Beds
BalancedPressure
ThermostaticAir Vent
Strainer
BalancedPressure
ThermostaticAir Vent
Float &ThermostaticSteam Trap
with SLRfeature
SightGlass
GravityCondensate
Return
AirReservoir
Steam Main
RotatingCylinder
Drain toSafe Place
Float &ThermostaticSteam Trap
Drain toSafe Place
The Spirax Sarco units (Strainers,Float & Thermostatic Steam Traps withSLR feature, Sight Glass, Air Reservoirwith Air Vent) provides for the bestdrainage of condensate and non-condensibles from rotating cylinders.
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HOOK-UP DIAGRAMS
Figure II-57 Draining High Speed Paper Machine using Cascading or “Blow-through” Systems
Paper Machines running at higherspeeds in modern plants usually havea cascading or “blow-through” sys-tem. Condensate is swept by the flowof blowthrough steam, up the dryercan dip pipe and into a manifold lead-ing to a blowthrough separator.Control of the blowthrough steammay be at the separator outlet or on
individual cylinders or banks of cylin-ders. The blow-through steam maypass on to sections of the machineoperating at lower pressures. Theblowthrough separator is drained byan FT trap, unless the return is pres-surized in which case a closed loopcombination pressure poweredpump/trap is required.
Figure II-58 Draining High Speed Paper Machine using “Thermal-compressor” or Reused Steam SystemsaaaaaaaaaaaaaaaaaaaaaaaaaaThermo-Dynamic
Steam Trapwith Integral
Strainer
Spira-tecLoss Detector
Float &ThermostaticSteam Trap
Thermo-DynamicSteam Trapwith Integral
Strainer
Spira-tecLoss Detector
Safety Valvewith Drip
Pan Elbow
Float &ThermostaticSteam Trap
Safety Valvewith Drip
Pan Elbow
Separator
Blow throughSeparator
CondensateReturn
CondensateReturn
DryerCans
CheckValve
CheckValve
L.P. SteamH.P. Steam
Thermal Compressor
L.P.Steam
By-Pass
Modern paper machines also use “Thermal-compre-sor” systems. Condensate is swept by the flow ofblow-through steam up the dryer can dip pipe andinto a manifold leading to a separator. The L.P.steam from the separator is then reused through anH.P. steam driven thermal compressor or by-passed.The separator is drained like Fig. II-57 or engineeredsystems package, Fig. II-58A.
Figure II-58A Condensate Removal ModuleHigh speed paper machines can be fitted witha preassembled module that incorporates theseparator and condensate removal equipment.
DryerCans
SteamTrap
Station
See Fig. II-58A forthe preassembled
CondensateRemoval Module
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HOOK-UP DIAGRAMS
Figure II-59Air Venting and Condensate Drainage at Jacketed Kettle
Figure II-60Draining Tire MoldaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaFigure II-61
Steam Trapping High Pressure Coil (up to 600 psig)
Float &ThermostaticSteam Trap
Strainer
BalancedPressure
ThermostaticAir VentSteam
Supply
Thermo-Dynamic
Steam Trapwith Integral
Strainer
Spira-tecLoss
Detector
Spira-tecLoss
Detector
CondensateReturn
Float &ThermostaticSteam Trap
Strainer
BalancedPressure
ThermostaticAir Vent
Strainer
HPHeating
Coil
Condensate Return
Air
SteamSupply
(Air supply temp. not lower than 32°F)
Strainer
Thermo-Dynamic
Steam Trap
SteamSupply
FlexibleQuick
DisconnectLines
Drain toSafePlace
Drain toSafePlace
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HOOK-UP DIAGRAMS
Figure II-62Draining High Pressure Reboiler
Figure II-63Draining Condensate to Vented Receiver andLifting Condensate to Overhead Return Main
Reboiler
Float &ThermostaticSteam Trap
Strainer
BalancedPressure
ThermostaticAir Vent
Strainer
Condensate Return
SteamSupply
Total back pressure is the height (H)in feet x .0433 plus PSIG in returnline, plus downstream piping frictionpressure drop in PSI (Determined bythe maximum instantaneous dis-charge rate of the selected pump.)
Drain toSafePlace
Thermo-Dynamic
Steam Trap
Float &ThermostaticSteam Trap
Strainer
Spira-tecLoss Detector
Thermo-Dynamic
Steam Trap
VentedReceiver
Return LinePressure Gauge
CondensateReturn Main
MotiveSupply
Strainer
SteamSpace
PressurePowered
Pump
Vent toAtmosphere
FillingHead
TotalLift“H”
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HOOK-UP DIAGRAMS
Figure II-64Draining Evaporator whenEvaporator Steam Pressurecan fall from Above to BelowBack Pressure
Figure II-65Draining Condensate from vacuum Space to Return Main or Atmosphere Drainaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa aaaaaaaaaaaaaaaaaaaaaaaaaaa
Evaporator
ReservoirStrainer
ReturnMain
BalancedPressure
ThermostaticAir Vent
Thermo-Dynamic
Steam Trap
PressurePowered
Pump
1" Equalizer Line
Float &ThermostaticSteam Trap
MotiveSteamSupply
VacuumSpace
Reservoir
Strainer
ReturnMain
Thermo-Dynamic
Steam TrapPressurePowered
Pump
SteamSupply
Pipe toDrain
Pipe toDrain30"
WaterColumn
TotalLift“H”
FillingHead
1" Equalizer Line
ElevatedDischarge
Connection
1/8"Antisyphon
Hole
Drain toSafePlace
Check Valve
BackPressure
EvaporatorPressure
Drain toAtmosphere
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HOOK-UP DIAGRAMS
Figure II-66Lifting Fluids from Low Pressure Sourceto Higher Pressure Receiver
Figure II-67Draining Equipment with Condensate Outlet Near Floor Level using a Pump/Trap Combination in a Pitaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa a aaaaaaaaaaaaaaaaaaaaaaaaaaaaaa a aaaaaaaaaaa a aa aaaaa aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa a aaaaaaaaaaaa a a aaaaaaaaaaaaaa aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa aaaaaaaaaaaaaaaaaaaaaa aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa aaaaaaaaaaaaaa a aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
Reservoir
Strainer
BalancedPressure
ThermostaticAir Vent
SteamSupply
Low PressureSpace
Thermo-Dynamic
Steam TrapPressurePowered
Pump
PressurizedReceiver
Tank
Reservoir Pipe
Strainer
BalancedPressure
ThermostaticAir Vent
Motive Gas orSteam Supply
Thermo-Dynamic
Steam TrapPressurePowered
Pump
Float &ThermostaticSteam Trap
Equalizer Line
1" Equalizer Line
Total back pressureis the height (H) infeet x 0.433 plusPSIG in receiver, plusdownstream pipingfriction pressure dropin PSI (Determinedby the maximuminstantaneous dis-charge rate of theselected pump.)
Drain toSafePlace
Drain toSafe Place
Check Valve
CheckValve
TotalLift“H”
CheckValve
Check Valve
Check Valve
Drain toSafePlace
ToPressurized
Storage Tank
Plug
Condensatefrom
Equipment
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HOOK-UP DIAGRAMS
When multiple pumps in parallelare used to meet the load, Pump#1 fills first and Pump #2 operatesat full load. Supply piping isarranged to reduce simultaneousdischarge. Better staging occurswhen Pump #2 is elevated 3” to 6”above the floor.Intake pipe to Pump #3 is locatedabove the Filling Head requiredby Pump #1 & #2 so it will functionas a “Standby” and only operateon peak loads or in the event ofprimary pump failure.
Figure II-68Installation of Pump/Trap Combinationwhen Vertical Space is Limited
Figure II-69Multiple Pressure Powered Pump Hookupsfor Staged Operation and Standby Duty
PressurePoweredPump #3
PressurePoweredPump #1
PressurePoweredPump #2
Receiver
Condensate
Supplies
Vent
Return
Return
Exhaust
PPF-Top
PressurePowered
Pump
Reservoir
Strainer
BalancedPressure
ThermostaticAir Vent
Thermo-Dynamic
Steam Trap
ReturnMain
Float &ThermostaticSteam Trap
Drain toSafePlace
Check Valve
Check Valve
MotiveSupply
Drain toSafePlace
CheckValve
Condensatefrom Process
Equipment
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HOOK-UP DIAGRAMS
Figure II-70Pressure Powered Pump Draining Water from Sump Pit
Figure II-71Pressure Powered Pump Discharging to Long Delivery Line(Air Eliminator needed above return main wherever
elevation changes form a water seal.)
Total back pressure is theheight (H) in feet x .0433 plusPSIG in return line, plusdownstream piping frictionpressure drop in PSI(Determined by the maximuminstantaneous discharge rateof the selected pump.)
ReturnMain
PressurePowered
Pump
Receiver
PressurePowered
Pump
Condensate
VacuumBreaker
Float OperatedAir Vent
ReceiverWaterSeal
Strainer
Thermo-Dynamic
Steam Trap
Pump ExhaustPiped to Safe Place
MotiveSupply
Drain
OperatingWaterLevel
15°SwingCheck
Figure II-72Pressure Powered Pump Discharging toLong Delivery Line with Lift at Remote End
See Fig. II-72 forhook-up option withLift at Remote End
Receiver
ReturnMain
Line SizeCheck Valve
Height“H”
Covering Grate
Line SizeCheck Valve
Line SizeCheck Valve
Line SizeCheckValve
Strainer
MotiveSupply
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HOOK-UP DIAGRAMS
Figure II-73Draining Small Condensate Loads fromVacuum using Atmospheric Pressure
Figure II-74Typical Electric Pump Hook-upfor Subcooled Condensate
Figure II-75Electric Pump Lifting Condensatefrom Vented Receiver to HigherPressure or Elevation
Vent toAtmosphere
PumpDischarge
Condensate fromLow Pressure
System
Floor
PressurePowered
Pump
Inlet Open toAtmosphere
Check valve should be vacuumtight and water sealed. Largerdrop reduces emptying time.
Sub Atmospheric Line
EqualizerLine
To Drain
SwingCheckValve
MinimumDrop 3"
Receiver
ElectricCondensate
Pump
ElectricCondensate
Pump
Strainer
PumpDischarge
Vent
H. P.Condensate
Drain
Gate &Check Valves
VentHead
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HOOK-UP DIAGRAMS
Figure II-76Typical Flash SteamRecovery Hook-up
Figure II-77Flash Steam Recovery with Live Steam Make upand Back Pressure Surplussing Valves
Condensate from high pressure loads releases steam by flash-ing as it passes to the lower pressures, downstream of the highpressure traps. The mixture of steam and condensate is readi-ly separated in Flash Vessels of appropriate dimensions andproportions. A supply of Low Pressure steam then becomesavailable for use on any application which can accept steam atthis low pressure, or the separated steam may simply be takeninto the LP steam mains, where it is supplemented throughpressure reducing valves, for general plant use.Where the supply of flash steam may at times exceed thedemand from the LP system, the surplus flash steam can bedischarged through a back pressure control valve. This is setat a few psi above the normal LP steam pressure, but belowthe setting of the LP safety valve. See Figure II-77.The condensate leaving the flash recovery vessel is at low pres-sure. Usually it is handled by a float-thermostatic steam trap andis delivered to the receiver of a condensate pump for return tothe boiler house. Any residual flash steam from the low pressurecondensate is vented from the pump receiver. (Figure II-78.)In some cases, pressures are sufficiently high that the flashcan be taken off at an intermediate pressure and the con-densate leaving the flash vessel still contains a usefulamount of sensible heat. It can then be taken to a secondflash vessel working at low pressure, so that the maximumheat recovery is effected. The use of two flash vessels inseries, or “cascade”, means that these vessels may beinstalled generally as Figure II-76 and II-77.Alternatively, it may be desirable to use the recovered flashsteam at a low pressure, below that in the condensate returnline or perhaps the de-aerator tank. The arrangement adapt-ed may then be either as Figure II-78 or as Figure II-79. Thislatter system uses a steam powered pump, with the bottomof the flash recovery vessel serving as the pump receiver.Power steam used by the pump is vented to the LP steamline, so that pumping is achieved at virtually zero cost and theuse of unsightly or wasteful vents is avoided.
Strainer
ThermostaticAir Vent
Float &ThermostaticSteam Trap
Strainer
ThermostaticAir Vent
Strainer Float &ThermostaticSteam Trap
Spira-tecLoss
Detector
SafetyValve
Spira-tecLoss
Detector
Strainer
Float &ThermostaticSteam Trap
Spira-tecLoss Detector
SafetyValve
Strainer
FlashRecovery
Vessel
FlashRecovery
Vessel
MoistureSeparator
Pilot OperatedPressure
Control Valve
H. P. Condensate
H. P.SteamSupply
L. P.Steam
Pilot OperatedBack PressureControl Valve
Vent
L. P.Condensate
H. P. Condensate
L. P. Steam Main
L. P.Condensate
DripPan Elbow
DripPan
ElbowH. P. Condensate
CheckValve
Drain toSafe Place
Drain toSafePlace
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HOOK-UP DIAGRAMS
Figure II-78Flash Steam Recovery at Pressure above Atmospheric with L.P.Condensate Returned by Packaged Pressure Powered Pump Unit
Figure II-78ACondensate Recovery Module
A preassembled modular pumpingsystem provides a sole sourcesolution for condensate recoveryapplications.
Strainer
Float &ThermostaticSteam Trap
Spira-tecLoss
Detector
SafetyValve
FlashRecovery
Vessel
MoistureSeparator
Strainer Float &ThermostaticSteam Trap
Spira-tec LossDetector
Strainer
Strainer
H. P. Condensate
Pilot OperatedBack PressureControl Valve
Pilot OperatedPressure
Control Valve
PressurePowered
Pump
Strainer
Vent
DripPan
Elbow
L.P.Condensate
Inlet
Thermo-Dynamic
Steam Trap
PackagedPressurePowered
Pump
CheckValve
High PressureMakeup Supply
Low PressureSteam System
CondensateReturn
Strainer
Vent toAtmosphere
Steam Trap Station
Steam Trap Station
See Fig. II-78A forthe preassembled
CondensateRecovery Module
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HOOK-UP DIAGRAMS
Figure II-79Flash Steam Recovery at Pressure Above or Below Atmosphericin ASME Coded Receiver of Packaged Pump Unit
Figure II-79ACondensate and Flash SteamRecovery Module
A preassembled modular pumpingsystem will recover condensate anddirect flash steam to a low pressure user.
Strainer
Float &ThermostaticSteam Trap
SafetyValve
MoistureSeparator
Strainer
Float & ThermostaticSteam Trap
Strainer
Strainer
H. P.MakeupSupply
ToCondensate
ReturnMain
Motive SteamSupply
Vent toAtmosphere
Pilot OperatedPressure ReducingValve (for makeup)
PressurePowered
Pump
Pilot OperatedBack PressureControl Valve
H. P.Condensate(from traps)
DripPan
Elbow
L. P.MakeupSupply
Overflowto
Drain
Packaged ASMECode Stamped
Pressure PoweredPump Unit
Steam Trap Station
See Fig. II-79A for the preassembledCondensate and Flash Steam
Recovery Module
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HOOK-UP DIAGRAMS
Figure II-80Heating Water using Recovered Flash Steam with PackagedPump Unit Also Handling Other Condensate
Strainer
SafetyValve
FlashRecovery
Vessel
ThermostaticAir Vent
Strainer
Float & ThermostaticSteam Trap
Thermo-Dynamic
Steam Trap
Strainer
Heated Water
MotiveSteamor Gas
Vent toAtmosphere
Heat Exchanger
PressurePowered
Pump
CondensateReturn
Float & ThermostaticSteam Trap
VacuumBreaker
Cold Water Inlet
H.P.Condensate
& Flash
PumpExhaust
Pilot OperatedBack PressureControl Valve
Condensate from high pressure steam sources iscollected in a flash steam recovery vessel. Flashsteam is separated from the condensate whichdrains through an F & T trap set to the vented receiv-er of a condensate pump. The flash steam iscondensed in a heat exchanger, giving up its heatcontent to the water which is to be heated (or pre-heated). Condensate from the exchanger also drainsthrough an F & T trap set to the pump receiver. Non-condensibles are discharged at the receiver vent.
DripPan
Elbow
Pipe toSafe Place
Steam Trap Station
Steam Trap Station
See Fig. II-80Afor the
preassembledCondensate
RecoveryModule
Figure II-80ACondensate Recovery ModuleA preassembled modular pumping system can be usedto recover and reuse the condensate.
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HOOK-UP DIAGRAMS
Figure II-81Heating Water using Flash Steam Recovered in ASME CodedReceiver of Packaged Pressure Powered Pump Unit
Strainer
SafetyValve
ThermostaticAir Vent
Thermo-DynamicSteamTrap
StrainerHeated Water
Vent toAtmosphere
Heat Exchanger
PressurePowered
Pump
CondensateReturn
Cold Water Inlet
H.P.Condensate
& Flash
PumpExhaust
Pilot OperatedBack PressureControl Valve
DripPan
ElbowPipe to
Safe Place
PackagedASME CodeStamped Unit
125
HOOK-UP DIAGRAMS
Figure II-82Recovery of Flash Steam and Pump Power Steam on Preheater (Steam in the Shell)
Condensate from the main heatexchanger flows to a flash SteamRecovery Vessel. The flash steam isseparated and led to the Preheaterwhere it is condensed as it preheatsthe incoming cool water or other liq-uid. Any incondensibles aredischarged to atmosphere throughthe thermostatic air vent.
Residual condensate from the flashvessel, with that from the preheater,falls to the inlet of the PressurePowered Pump. Pump exhauststeam is taken to the Flash Steamline and its heat content recovered inthe preheater.
A Packaged Pump Unit with ASMEcoded receiver can be used in placeof the component flash vessels andPressure Powered Pump.
SafetyValve
FlashRecovery
Vessel
Strainer
Float &ThermostaticSteam Trap
Strainer
Heat Exchanger
PressurePowered
Pump
ToCondensate
Return
VacuumBreaker
CoolReturn
SteamSupply
PilotOperated
BackPressure
Valve
Float &ThermostaticSteam Trap
Pre-Heater
AirVent
ToVent
MoistureSeparator
Strainer
TemperatureControlValve
ToVent
AirVent
Strainer
Thermo-DynamicSteam Trap
Sensor
HeatedOutlet
Pipe toSafePlace
CheckValve
Pipe toSafePlace
Motive Steam Supply
DripPan
Elbow
CheckValve
CheckValve
126
HOOK-UP DIAGRAMS
Figure II-83Recovery of Flash Steam and Pump Power Steam in Preheater (Steam in Tubes)
Safety Valvewith Drip
Pan Elbow
FlashRecovery
Vessel
Strainer
Float &ThermostaticSteam Trap
Strainer
HeatExchanger
PressurePowered
Pump
CondensateReturn
VacuumBreaker
BackPressureControlValve
Float &ThermostaticSteam Trap
Air Vent
MoistureSeparator
Strainer
TemperatureControlValve
Float &ThermostaticSteam Trap
Strainer
Pre-Heater
ToVent
SightGlass
Spira-tecLoss
Detector
Strainer
CoolReturn
ToVent
HeatedOutlet
CheckValve
Pipe toSafePlace
127
HOOK-UP DIAGRAMS
Figure II-84Flash Steam Condensing by Spray
Residual flash steam for which nouse can found often causes a nui-sance if vented to atmosphere, andof course carries its valuable heatcontent with it. This steam may becondensed by spraying in cold water,in a light gauge but corrosion resis-tant chamber fitted to the receiver
tank vent. If boiler feed quality wateris used, the warmed water and con-densed flash steam is added to thecondensate in the receiver andreused. Condensing water which isnot of feed water quality is kept sep-arate from the condensate in thereceiver as shown dotted.
A self-acting, normally closed tem-perature control with sensor in thevent line can control the coolant flow.This minimizes water usage, andwhere condensed flash steam isreturned, avoids overcooling of thewater in the receiver.
Overflow
CoolingWater
BoilerMakeup
TankCentrifugal
Pump
TemperatureControl Sensor
Waste
(Alternate)
Strainer
Condensate Receiver
H.P. Condensate
Vent
Self ActingTemperature
Control
FlashCondenser
128
HOOK-UP DIAGRAMS
Figure II-86Culinary/Filtered Steam Station
Figure II-85Clean Steam Drip Station
Strainer with aFine Mesh Screen
Float &ThermostaticSteam Trap
Strainer
Spira-tecLoss
Detector
MoistureSeparator
CleanSteamSupply
Stainless SteelThermo-Dynamic
Steam Trap
Stainless SteelBall Valve
Product/MediaLine
Sanitary DiaphragmValve with Inlet
Drain Boss
1:120 min.
1:120 min.
Condensate Manifoldmust be free draining
A
B
Install valve “A” close toproduct/media line.Close-couple valves “A” and “B”
Stainless SteelThermo-Dynamic
Steam Trap
Plant SteamInlet
SampleCooler
Stainless SteelBall Valve
Stainless SteelBall Valve
Steam Filterwith a 2.8 micron
absolute filterelement
AB
A All piping, fittings, valves, etc. downstreamof this point shall be of austenitic stainlesssteel and of sanitary design
B Recommended position of plant steampressure reducing valve if required
Pressure gauges, fittings, valves, etc., are notshown for clarity.
SanitaryCheck Valve
CoolingWaterOutlet
CoolingWaterInlet
CooledSample
129
HOOK-UP DIAGRAMS
Figure II-87 Tank Sterilization
Figure II-88Block and Bleed Sterile Barriers
Stainless SteelThermostaticSteam Trap
CleanSteamSupply
Product Outlet
DiaphragmValve
Stainless SteelBall Valve
Stainless SteelThermostaticSteam Trapinstalled as
Air Vent
Stainless SteelBall Valve
Stainless SteelBall Valve
Condensate
DiaphragmValve
DiaphragmValve
DiaphragmValve
Stainless SteelBall Valve
Stainless SteelThermo-Dynamic
Steam Trap
Stainless SteelThermostaticSteam Trap
AsepticProcess
Line
Sanitary DiaphragmValve with inlet Drain Boss
AsepticProcess
Line
Condenate Manifoldmust be free draining
SanitaryDiaphragm
Valve SanitaryDiaphragm
Valve
Stainless SteelBall Valve
1:120 min.
CleanSteamSupply
A
A Close-couple valves
130
HOOK-UP DIAGRAMS
Figure II-89Product/MediaProcess Line Sterilization
Figure II-90Pressure Regulating Stationfor Pure Steam Service
Figure II-91Sterilizer Utilizing High Purity Steam
Stainless SteelThermostaticSteam Trap
Product/MediaLine
Sanitary DiaphragmValve with inlet Drain Boss
CondenateManifold
must be freedraining
SanitaryDiaphragm
Valve
Stainless SteelBall Valve
1:120 min.
CleanSteamSupply
A
A Close-couple Diaphragm Valves
Stainless SteelBall Valve
Stainless SteelThermo-Dynamic
Steam Trap
Stainless SteelBall Valve
Stainless SteelBall Valve
Stainless SteelSteam Separator
SanitaryPressureRegulator
ReducedSteam
Pressure
Stainless SteelBall Valve
PureSteamSupply
See Fig. II-85for proper CleanSteam hook-up
to product/medialine
A
Stainless SteelThermo-Dynamic
Steam Trap
Stainless SteelBall Valve
Stainless SteelSteam Separator
PureSteamSupply
Stainless SteelBall Valve
SanitaryPressureRegulator
Stainless SteelThermo-Dynamic
Steam Trap
Stainless SteelBall Valves
Stainless SteelBall Valve
Stainless SteelBall Valve
StainlessSteel
Ball Valve
Stainless SteelThermostaticSteam Trapinstalled asan Air Vent
Stainless SteelThermostaticSteam Trapinstalled asan Air Vent
Stainless SteelBall Valves
Stainless SteelThermostaticSteam Traps
Stainless SteelBall Valves
Note: Provide over pressure protection forchamber and jacket with properly sizedsafety valve(s) or rupture disc(s).
Sterilizer
131
HOOK-UP DIAGRAMS
Figure II-92Spiraflo Saturated Steam(Density Compensated) Metering System
Figure II-93Typical Superheated Steam (Density Compensated) Metering System
ThermostaticAir Vent
Float &ThermostaticSteam Trap
Strainer
SteamSeparator
IsolatingValve
CheckValve
SpirafloSteam Meter
Gilflo Meter
IsolatingValve
IsolatingValve
PressureTransmitter
FlowComputer
DifferentialPressure
Transmitter
3-ValveManifold
TemperatureTransmitter
Note: The same configuration issuitable for the Standard Range Gilflo,Gilflo ILVA and Orifice Plate Systems.
SteamSupply
Pipe toSafePlace
SteamSupply
CheckValve
SignalConditioning
Unit
FlowComputer
132
HOOK-UP DIAGRAMS
Figure II-94Typical Saturated Steamor Liquid Metering System(No Density Compensation)
Figure II-95Typical Saturated Steam(Density Compensated)Metering System
Figure II-96Typical Saturated Steam(Density Compensated)Metering System
Orifice Plate
IsolatingValve
IsolatingValve
FlowIndicator
DifferentialPressure
Transmitter
3-ValveManifold
Note: The same configuration issuitable for the Gilflo, Standard RangeGilflo, and Gilflo ILVA Systems.
Note: The same configuration issuitable for the Gilflo, Standard RangeGilflo, and Orifice Plate Systems.
For Saturated Steam, DensityCompensation is achieved by theflow computer accepting a signal fromeither a Temperature Transmitter(as shown here) or a PressureTransmitter (see Fig. II-96)
Gilflo ILVA
IsolatingValve
IsolatingValve
FlowComputer
DifferentialPressure
Transmitter
3-ValveManifold
TemperatureTransmitter
Gilflo ILVA
IsolatingValve
IsolatingValvePressure
Transmitter
FlowComputer
DifferentialPressure
Transmitter
3-ValveManifold
Note: The same configuration issuitable for the Gilflo, Standard RangeGilflo, and Orifice Plate Systems.
For Saturated Steam, DensityCompensation is achieved by theflow computer accepting a signalfrom either a Pressure Transmitter(as shown here) or a TemperatureTransmitter (see Fig. II-95)
SteamSupply
Steamor LiquidSupply
SteamSupply
133
HOOK-UP DIAGRAMS
Figure II-97Hand Operated Rotary Filter
Figure II-98Motorized Rotary Filter with Single Blowdown Valve
Figure II-99Control Panel Hook-up for One Valve Blowdown VRS-2 Rotary Filter System
MainPower
D.P.Switch
MotorWiring
Model VRSControl Panel
ValveWiring
InletPressure
Line Model VRS-2Rotary Filter
ReservoirPipe
RemovedSolids
RemovedSolids
DirtyMedia
Hand OperatedRotary Filter
FilteredMedia
HandOperatedBlowdown
Valve
RemovedSolids
DirtyMedia
MotorizedRotary Filter
FilteredMedia
Full PortQuarter Turn
Motorized Valve
Electric Supplyto Motor
Electric Supply toMotorized Valve
ReservoirPipe
Control of rotor and blowdownvalve is made with user sup-plied timers. The blowdownvalve should stay open forapproximately 10 seconds topurge filtered dirt and debrisfrom reservoir pipe. Intervaland duration of the rotor andblowdown valve will varydepending on the nature andquantity of the dirt and debris.
Full PortQuarter Turn
MotorizedValve
P1 P2Outlet
PressureLine
The Control Panel with useradjustable timers controls intervaland duration of the rotor and blow-down valve operation. The blowdownvalve opens for approximately 10
seconds to purge the reservoir pipeof filtered dirt and debris. The ControlPanel is shown with optional cyclecounter and differential pressureswitch which will activate rotor opera-
tion if excessive pressure dropoccurs. This hook-up illustrates anautomatic filtration system, providingcontinuous production flow with mini-mal product loss.
134
HOOK-UP DIAGRAMS
Figure II-100Control Panel Hook-up and Operation of Two Valve Blowdown VRS-2 Rotary Filter System
Figure II-101Motorized Rotary Filter withThree Valve Blowdown Systemfor Viscous FLuids
The Control Panel operates rotor andblowddown valves CV1 and CV2automatically. Fig. II-100A shows thenormal running mode with CV1 valveopen and CV2 valve closed, to allowreservoir to fill with dirt and debris. As
the reservoir pipe fills, valve CV1closes and valve CV2 opens purgingonly material held in the reservoir leg,Fig. II-100B. CV2 closes and CV1reopens returning system to normalrunning mode with no stoppage of
flow. This hook-up illustrates an auto-matic filtration system, providingcontinuous product flow with virtuallyno loss of usable fluid.
MainPower
D.P.Switch
MotorWiring
Model VRSControl Panel
ValveWiring
InletPressure
LineModel VRS-2Rotary Filter
ReservoirPipe
MainPower
D.P.Switch
MotorWiring
Model VRSControl Panel
ValveWiring
InletPressure
LineModelVRS-2
Rotary Filter
ReservoirPipe
MainPower
D.P.Switch
MotorWiring
Model VRSControl Panel
ValveWiring
InletPressure
LineModelVRS-2
Rotary Filter
ReservoirPipe
RemovedSolids
RemovesSolids
RemovedSolids
Full PortQuarter Turn
MotorizedValves
HighPressure
PurgeSee Fig. II-100A and II-100B for sequence ofoperation. In addition tothe blowdown valves onthe reservoir pipe, a thirdvalve CV3 has been addedfor a high pressure purgefluid or air should thedebris in the reservoir pipeprove to be too viscous toflow by gravity.
P1 P1P2P2
CV1
CV2
CV1
CV2
Full PortQuarter Turn
MotorizedValve
Full PortQuarter Turn
MotorizedValve
Figure II-100A Figure II-100B
OutletPressure
Line
OutletPressure
Line
P1 P2
CV1
CV2
CV3
OutletPressure
Line
135
HOOK-UP DIAGRAMS
Figure II-102Freeze Proof Safety Showerwith Antiscalding Protection
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa a aaaaaaaaFigure II-103Automatic Contol of Smaller CompressorCooling with Overheat Protection
The T-44 control valve incorporates a bypass needle valve to keep a min-imum flow of water past the sensor even when the main valve has closed.A float-type drainer is preferred for the separator rather than a TD drainer,to ensure immediate and complete drainage of the separated liquid.Larger compressors or low pressure cooling water supplies may call for aseparate supply of water to the aftercooler, with a solenoid valve orsimilar, to open when the compressor runs.
Fit T-44 control (withbypass closed), 85˚Fto 135˚F range, in 1-1/4” or larger pipe.Flow crosses sensorto shower, to coolingvalve inlet ending atthe #8 that openswhen ambient dropsbelow 40°F. Line flowprevents both freezeup and solar over-heating.
Drain
Strainer
LiquidDrainTrap
Air Line
MoistureSeparator
Strainer
CoolingControl
FloatOperatedAir Vent
CoolingWater
WarmedCoolant
CompressorJacket
AfterCooler
WaterSupply
#8 set@ 40°F
Strainer
CoolingControl
Spring ClosedValve To
Shower Head
OverheatDrain
136
HOOK-UP DIAGRAMS
Figure II-104Condensate Cooling System
Figure II-105Condensate Cooling and Flash Knockdown System
CoolingControlValve
Sensor
VacuumBreaker
VacuumBreaker
To Drain140°FMax.
Flash Tank
CondensateReturn
CoolingWater
ToVent
Sparge Pipe
CoolingControlValve
Sensor
To Drain140°FMax.
Flash Tank
CondensateReturn
CoolingWater
ToVent
Spray Nozzle
137
HOOK-UP DIAGRAMS
Figure II-106Continuous Boiler BlowdownCooling System
Figure II-107Controlling Coolant Flow to Vacuum StillCondenser and Draining Evaporator
Float & ThermostaticSteam Trap
Strainer
Evaporator
Self ContainedTemperature
Control
Spira-tecLoss
Detector
Thermo-DynamicSteam Trapwith Integral
Strainer
Spira-tecLoss
Detector
Condenser
ColdWaterSupply Waste Water
Sight Drain
Distillate
Strainer
Steam Main
CoolingControlValve
Sensor
VacuumBreaker
ContinuousBoiler
Blowdown
CoolingWater
BlowdownVessel
ToVent
SpargePipe
To Drain140°FMax.
GravityCondensate
Return
VentHead
138
HOOK-UP DIAGRAMS
Figure II-108ControllingTemperatureof Ball GrindingMill Jacket
Figure II-109Controlling Temperature of Oil Cooler
Figure II-110Controlling Temperature of Horizontal Solvent Condenser
Strainer
ColdWaterSupply
CoolerFilter
Drain
Hot Solvent
CoolingWaterOut Cooled
SolventCoolingWater
Discharge
Self ContainedCooling Control
SightDrain
Strainer
Cool Oil
Oil Cooler
Hot Oil
Self ContainedCooling ControlCold
WaterSupply
Strainer
Grinding Mill
CoolingControl ValveCold
WaterSupply
SightDrain
WaterJacket
TemperatureControlSensor
SightDrain
CheckValve
139
HOOK-UP DIAGRAMS
Figure II-112Cooling Water Economizerfor Multiple Rolls
Figure II-111Controlling Temperatureof Vertical Solvent Still
Strainer
Self ContainedCooling Control
CoolingWater
Discharge
Roll
Roll
Roll
FloatOperatedAir VentCold
Water
Perforated PipeHoles Pointing Down
Mixing Tank
CentrifugalPump
FlowBalancing
Valve
Strainer
ColdWaterSupply
Cooler
Solvent
Filter
Drain
Drain
Self ContainedCooling Control
Solvent toEquipment
Pipe WasteWater
To Drain
CheckValve
Drain
140
HOOK-UP DIAGRAMS
Figure II-113Alternate Methods of Draining Compressed Air Receiver
Figure II-114Draining Compressed AirDropleg to Equipment
Figure II-115Draining Riser in CompressedAir Distribution Line
Strainer
LiquidDrainTrap
LiquidDrainTrap
Strainer
Equipment Supply
Main
Drain Drain
Main Supply
BalanceLine
Branches are best takenoff the top of main lines.Condensation sweptalong the lines when airtools are used may over-load the filter of the airset at the take-off point,so a drainer is providedat the bottom of the sup-ply leg to remove asmuch as possible of thiscondensation.
Balance lines are notalways necessary onAir Drainers. Theybecome necessarywhen the trap locationis more remote fromthe line being drainedand when condensa-tion quantities aregreater. It is preferredto connect balancelines downstream ofthe point beingdrained.
LiquidDrainTrap Strainer
Balance Line
LiquidDrainTrap
Strainer
Air Receiver
Small air receivers are often“drained” through a manual valve atlow level on a once per day basis.Continuous drainage helps to main-tain better quality in the air supplied
but small receivers may be mountedso low as to preclude the use of theCA14 or FA pattern drainers. Thedrain point may be in the center of
the dished end of even on top, withan internal dip pipe to reach the col-lected liquid. The only possibleoption is the TD drainer.
141
142
PRODUCTINFORMATION
Section 3
Product Information
144
PRODUCT INFORMATION
• Pressure Powered Pumps™ • Packaged Pressure Powered Pumps™
• High Capacity Pressure Powered Pump™ • Electric PumpsSpirax Sarco offers the solutions to maintaining efficiency in all areas of
condensate recovery. For the total system solution, Spirax Sarco’s non-electricpumps drain and return condensate and other liquids from vacuum systems,condensers, turbines, or any other steam condensing equipment. The PressurePowered Pump™ can handle liquids from 0.65 to 1.0 specific gravity and capac-ities up to 39,000 lb/hr. Available in cast iron or fabricated steel (ASME codestamped) with stainless steel internals and bronze or stainless steel checkvalves, the rugged body allows a maximum pressure of 125-300 psig and a max-imum temperature of 450˚F. This system solution saves energy and providesoptimum system efficiency with low maintenance.
For easy installation, Pressure Powered Pump™ packaged units are pre-piped and combine any Pressure Powered Pump™, up to 3" x 2" with a receiver.
Spirax Sarco’s electric pumps are packaged units completely assembled,wired and tested. Electric condensate return pumps are available in simplexunits with an integral float switch or a mechanical alternator on the duplex units.
• Automatic Control Valves• Direct Operated Temperature Regulators• Direct Operated Pressure Regulators• Pilot Operated Temperature Regulators• Pilot Operated Pressure Regulators• Safety Valves
Maximum productivity requires delivering the steam at its most energyefficient pressure and temperature resulting in optimum energy usage, and asafe, comfortable environment. Spirax Sarco has a complete range of controls toefficiently provide the right heat transfer for any process or heating application.
Ranging in sizes from 1/2" to 6", operating pressures up to 600 psi, andcapacities up to 100,000 lb/hr, the complete range of controls and regulatorsprovide steam system solutions industry wide. Available in iron, steel, stainlesssteel, and bronze, Spirax Sarco controls and regulators are suitable for virtuallyall control applications.
Controls & Regulators
• Type VRS-2 Motor-Operated Rotary Filter • Model VRS Control Panel• Type VRS-2 Hand-Operated Rotary Filter
Filtration of foreign matter from fluids is an industry problem and SpiraxSarco has the ultimate products to provide a cost effective solution. The modelVRS-2 Rotary Filter provides an automatic self-cleaning filtration systemdesigned to meet today’s industrial requirements. The unique design of theVRS-2 provides a way to maintain a clean filter element with no interruption offlow or pressure drop, alleviating maintenance and downtown, and increasingproductivity and profitability. The VRS-2 offers numerous advantages, allowingfiltration of virtually any fluid in an environmentally safe and economical way.
The VRS-2 Rotary Filter is available in cast iron, steel, and stainless steel, withNPT, socket weld, and ANSI flanged connections, stainless steel internals withretention range of 3/4" perf to 75 micron and sizes ranging from 3/4" to 12" withflow rates to 5,000 GPM liquid capacity. The VRS-2 Control Panel provides a fully-automatic system to operate all functions of the motorized rotary filter product line.
Rotary Filters
Condensate Recovery
Product Information
145
• Balanced Pressure Thermostatic • Bimetallic• Float & Thermostatic • Inverted Bucket• Thermo-Dynamic® • Liquid Expansion• Steam Trap Fault Detection Systems • Steam Trap Diffuser
Spirax Sarco designs and manufactures all types of steam traps in a varietyof materials. Whether it be for steam mains, steam tracing, or heating andprocessing equipment, Spirax Sarco has the knowledge, service and productsto improve your steam system.
Mechanical steam traps are available in iron and steel with NPT, socketweld, or flanged connections in sizes ranging from 1/2" to 4". Thermostatic typesare available in brass, forged steel, stainless steel, cast alloy steel with stainlesssteel internals with NPT and socket weld connections and are available in sizes1/2" to 1-1/2". The kinetic energy disc types are available in stainless, alloy andforged steel and range in sizes from 1/2" to 1" with NPT, Socket Weld and ANSIconnections.
Steam Traps
Many industrial processes involve the removal of a liquid from a pressurizedgas. Spirax Sarco Liquid Drain Traps are ideally suited for this purpose as wellas removing condensate from compressed air lines. The float operated designinstantly and automatically adjusts to variations in liquid load and pressure.
The traps can handle liquids with a specific gravity as low as 0.5. LiquidDrain Traps have a maximum operating pressure to 465 psi and range in sizefrom 1/4" to 4" with capacities of up to 900,000 lb/hr. Construction is cast iron,ductile iron, carbon steel or 316L stainless steel bodies with NPT, socket weld orflanged connections.
Liquid Drain Traps
• Flash Vessels • Steam Separators• Strainers - Pipeline and Basket • Sight Glasses/Checks• Air Handling Equipment • Trap Diffusers• Radiator Valves • Vent Heads• Ball Valves • Vacuum Breakers• Steam Injectors
The Spirax Sarco line of Pipeline Auxiliaries complete the steam system and areavailable in a variety of materials and sizes to suit your needs.
Pipeline Auxiliaries
PRODUCT INFORMATION
Product Information
146
PRODUCT INFORMATION
A comprehensive range of stainless steel products:• Steam Traps • Separators • Hygienic Ball Valves• Pressure Controls • Filters • Sample Coolers
The use of clean or pure steam to reduce the risk of product or processcontamination spans many industries and applications, including pure steam forsterilization of equipment in the biotechnology and pharmaceutical industries,culinary steam for direct cooking and heating of foods, clean steam for humidi-fication of clean rooms, and filtered steam for hospital sterilizers. Spirax Sarco’srange of stainless steel specialty products have been designed and manufac-tured to the highest standards and specifications required to withstand the rigorsof service in clean steam and other aggressive process fluids.
Stainless Steel Specialty Products
Complete modular solutions for steam users worldwide:• Preassembled Steam Trap Stations• Steam Distribution and Condensate Collection Manifolds• Forged Steel Manifolds• Process Condensate Removal Modules• Condensate and Flash Steam Recovery Modules
From institutional condensate recovery applications to draining critical processheat transfer equipment, Spirax Sarco’s modular pumping systems are the mostcost effective and provide the lowest total installed cost. The conventional methodof individually specified and procured components with on-site assembly is laborintensive and not conducive to today’s competitive plant standards.
The Engineered Systems Advantage expedites the installation process anddelivers a quality solution to numerous types of steam users. Each modularpumping system utilizes reliable Pressure Powered Pump™ technology andsaves 25% over the conventional method. Spirax Sarco backs each unit with asole source guarantee and unequaled expertise in steam system technology.
Engineered Systems
Years of accumulated experience has enabled the development and nurtur-ing of in-depth expertise for the proper control and conditioning of steam.Experienced field personnel work closely with design, operations, andmaintenance engineers, continuously evaluating ways to improve productivity.Often, these solutions pay for themselves many times over.
The four U.S. training centers located in Chicago, Houston, Los Angeles,and Allentown, Pa., have on-site steam systems providing hands-on training.Education programs include the theory of steam, the application of steamproducts, and plant design and system efficiency, to name just a few. Programsalso can be tailored to meet individual needs. Thousands of engineers completeSpirax Sarco training programs each year and return to continue broadeningtheir knowledge of steam systems.
Training
147
PRODUCT INFORMATION
148
PRODUCT INFORMATION
Diagram Index
149
PRODUCT INFORMATION
Page
Figure II-1 Boiler Steam Header . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .84
Figure II-2 Draining End of Low Pressure Steam Main . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .84
Figure II-3 Draining and Air Venting Steam Lines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .85
Figure II-4 Draining Expansion Loops . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .85
Figure II-5 Draining Steam Mains to Return Main at Same Level . . . . . . . . . . . . . . . . . . . . . . . . . . .86
Figure II-7 Hook-up with Condensate Return Line at High Level . . . . . . . . . . . . . . . . . . . . . . . . . . . .86
Figure II-8 Draining Steam Main where Trap must be at Higher Level . . . . . . . . . . . . . . . . . . . . . . . .87
Figure II-9 Condensate Drainage to Reinforced Plastic Return Line, with Overheat Protection . . . . .87
Figure II-10 Typical Steam Tracer Trapping Arrangements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .88
Figure II-11 Steam Tracing System with Preassembled Manifolds . . . . . . . . . . . . . . . . . . . . . . . . . . .88
Figure II-12 Typical Pressure Reducing Valve Station . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .89
Figure II-13 Parallel Operation of Pressure Reducing Valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .89
Figure II-14 Series Pressure Reducing Valve Station for High Turndown Rations . . . . . . . . . . . . . . . .90
Figure II-15 Hook-up for Remote Operation of 25 PRM Pressure Reducing Valve . . . . . . . . . . . . . . . .90
Figure II-16 Installation of Pressure Reducing Valve in “Tight Spaces” . . . . . . . . . . . . . . . . . . . . . . . .91
Figure II-17 Low Capacity Pressure Reducing Station . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .91
Figure II-18 25 BP Back Pressure Controls used to Restrict Supply to Low Priority Uses at
Times of Overload . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .92
Figure II-19 Reducing Steam Pressure Using 25PA Control Valve with Remote Air Valve . . . . . . . . . .92
Figure II-20 Typical Pneumatic Single Stage Pressure Reducing Valve Station . . . . . . . . . . . . . . . . . .93
Figure II-21 Pneumatic Temperature Control of Heat Exchanger . . . . . . . . . . . . . . . . . . . . . . . . . . . . .93
Figure II-22 Hook-up for 25 TRM Temperature Control Remotely Mounted
(within 15 ft. of Main Valve) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .93
Figure II-23 Pressure Reducing Valve for Pressure Powered Pump Motive Steam . . . . . . . . . . . . . . .94
Figure II-24 Heat-up, Pressuring and Shutdown of Steam Mains using On/Off Control Valves
and Programmer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .94
Figure II-25 Complete Condensate Drainage from Air Heater Coil under “Stall” with Combination
Pump/Trap in a Closed Loop System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .95
Diagram Index
150
PRODUCT INFORMATION
Figure II-26 Controlling and Draining Preheat and Reheat Coils in Vented Condensate System with
Freeze Resistant Piping for Makeup Air . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .96
Figure II-27 Freeze Proof Piping of Large Vertical Air Heater Coil to Atmospheric
Condensate Return System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .97
Figure II-28 High Pressure Steam Coils Trapped for Flash Recovery to LP Steam System . . . . . . . . .97
Figure II-29 Storage Cylinder with High Limit Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .98
Figure II-30 Condensate Drainage from Unit Heater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .98
Figure II-31 Temperature Control of Warm-up and Running Loads at Storage Tank . . . . . . . . . . . . . .99
Figure II-32 Draining Heat Exchanger under Constant “Stall” Condition with Pumping
Trap in Closed Loop System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .99
Figure II-33 Combined Pressure and Temperature Control of Heat Exchanger . . . . . . . . . . . . . . . . .100
Figure II-34 Draining Small Heat Exchanger and Other Loads to Pressure Powered Pump . . . . . . . .100
Figure II-35 Draining Equipment to Pressurized Return with Closed Loop Pump/Trap
Drainage System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .101
Figure II-34A Condensate Recovery Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .101
Figure II-35A Process Condensate Removal Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .101
Figure II-36 Low Pressure Steam Absorption Chiller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .102
Figure II-37 High Pressure Steam Absorption Chiller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .102
Figure II-38 Automatic Control of Batch Processor with Electrical Time Sequence Programmer . . . .103
Figure II-39 Controlling Temperature of Open Tank for Plating, Dyeing of Process Work . . . . . . . . . .103
Figure II-40 Controlling Platen Press Temperature with Pressure Regulator and
Electric Programmer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .104
Figure II-41 Controlling Temperature of Pressurized Boiler Feed Water Tank . . . . . . . . . . . . . . . . . .104
Figure II-42 Controlling Temperature of Vented Boiler Feed Water Tank . . . . . . . . . . . . . . . . . . . . . .105
Figure II-43 Controlling Temperature of Large Open Tank Heated by Direct Steam Injection . . . . . . .105
Figure II-44 Controlling Temperature of Small Open Tank, Heated by Direct Steam Injection . . . . . . .106
Figure II-45 Controlling Temperature of Water Supplied to Spray Nozzles of Egg Washing Machine .106
Figure II-46 Controlling Temperature of Greenhouse or Other Similar Buildings . . . . . . . . . . . . . . . .107
Figure II-47 Steam Radiator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .107
Figure II-48 Trapping and Air Venting Hospital Sterilizer with Dry Steam Supply . . . . . . . . . . . . . . . .108
Diagram Index
151
PRODUCT INFORMATION
Figure II-49 Control and Drainage Hook-up for Hospital Blanket and Bedpan Warmer . . . . . . . . . . .108
Figure II-50 Trapping Small Utensil Sterilizer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .109
Figure II-51 Condensate Drainage from Hospital Mattress Disinfector . . . . . . . . . . . . . . . . . . . . . . . .109
Figure II-52 Float & Thermostatic Trap Freeze Resistant Hook-up . . . . . . . . . . . . . . . . . . . . . . . . . .110
Figure II-53 Thermoton Controlling Temperature of Large Storage Tank . . . . . . . . . . . . . . . . . . . . . .110
Figure II-54 Equipment Drained with Permanent Connector Thermo-Dynamic Steam Traps that fit into
both Horizontal and Vertical Pipework . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .110
Figure II-55 Draining and Air Venting Flatwork Ironer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .111
Figure II-56 System Units for Condensate Removal and Air Venting of Rotating Cylinders
(for surface speeds below 800 FPM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .111
Figure II-57 Draining High Speed Paper Machine using Cascading or “Blow-through” Systems . . . . .112
Figure II-58 Draining High Speed Paper Machine using “Thermal-compressor” or Reused
Steam Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .112
Figure II-58A Condensate Removal Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .112
Figure II-59 Air Venting and Condensate Drainage at Jacketed Kettle . . . . . . . . . . . . . . . . . . . . . . . .113
Figure II-60 Draining Tire Mold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .113
Figure II-61 Steam Trapping High Pressure Coil (up to 600 psig) . . . . . . . . . . . . . . . . . . . . . . . . . . .113
Figure II-62 Draining High Pressure Reboiler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .114
Figure II-63 Draining Condensate to Vented Receiver and Lifting Condensate to
Overhead Return Main . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .114
Figure II-64 Draining Evaporator when Evaporator Steam Pressure can fall from Above
to Below Back Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .115
Figure II-65 Draining Condensate from vacuum Space to Return Main or Atmosphere Drain . . . . . . .115
Figure II-66 Lifting Fluids from Low Pressure Source to Higher Pressure Receiver . . . . . . . . . . . . . .116
Figure II-67 Draining Equipment with Condensate Outlet Near Floor Level using a
Pump/Trap Combination in a Pit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .116
Figure II-68 Installation of Pump/Trap Combination when Vertical Space is Limited . . . . . . . . . . . . . .117
Figure II-69 Multiple Pressure Powered Pump Hookups for Staged Operation and Standby Duty . . .117
Figure II-70 Pressure Powered Pump Draining Water from Sump Pit . . . . . . . . . . . . . . . . . . . . . . . .118
Figure II-71 Pressure Powered Pump Discharging to Long Delivery Line . . . . . . . . . . . . . . . . . . . . .118
Diagram Index
152
PRODUCT INFORMATION
Figure II-72 Pressure Powered Pump Discharging to Long Delivery Line with Lift at Remote End . . .118
Figure II-73 Draining Small Condensate Loads from Vacuum using Atmospheric Pressure . . . . . . . .119
Figure II-74 Typical Electric Pump Hook-up for Subcooled Condensate . . . . . . . . . . . . . . . . . . . . . .119
Figure II-75 Electric Pump Lifting Condensate from Vented Receiver to Higher
Pressure or Elevation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .119
Figure II-76 Typical Flash Steam Recovery Hook-up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .120
Figure II-77 Flash Steam Recovery with Live Steam Make up and Back Pressure
Surplussing Valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .120
Figure II-78 Flash Steam Recovery at Pressure above Atmospheric with L.P. Condensate Returned
by Packaged Pressure Powered Pump Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .121
Figure II-78A Condensate Recovery Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .121
Figure II-79 Flash Steam Recovery at Pressure Above or Below Atmospheric in ASME Coded
Receiver of Packaged Pump Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .122
Figure II-79A Condensate and Flash Steam Recovery Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .122
Figure II-80 Heating Water using Recovered Flash Steam with Packaged Pump Unit Also
Handling Other Condensate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .123
Figure II-80A Condensate Recovery Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .123
Figure II-81 Heating Water using Flash Steam Recovered in ASME Coded Receiver of Packaged
Pressure Powered Pump Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .124
Figure II-82 Recovery of Flash Steam and Pump Power Steam on Preheater (Steam in the Shell) . .125
Figure II-83 Recovery of Flash Steam and Pump Power Steam in Preheater (Steam in Tubes) . . . . .126
Figure II-84 Flash Steam Condensing by Spray . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .127
Figure II-85 Clean Steam Drip Station . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .128
Figure II-86 Culinary/Filtered Steam Station . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .128
Figure II-87 Tank Sterilization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .129
Figure II-88 Block and Bleed Sterile Barriers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .129
Figure II-89 Product/Media Process Line Sterilization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .130
Figure II-90 Pressure Regulating Station for Pure Steam Service . . . . . . . . . . . . . . . . . . . . . . . . . . .130
Figure II-91 Sterilizer Utilizing High Purity Steam . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .130
Figure II-92 Spiraflo Saturated Steam (Density Compensated) Metering System . . . . . . . . . . . . . . .131
Diagram Index
153
PRODUCT INFORMATION
Figure II-93 Typical Superheated Steam (Density Compensated) Metering System . . . . . . . . . . . . . .131
Figure II-94 Typical Saturated Steam or Liquid Metering System (No Density Compensation) . . . . . .132
Figure II-95 Typical Saturated Steam (Density Compensated) Metering System . . . . . . . . . . . . . . . .132
Figure II-96 Typical Saturated Steam (Density Compensated) Metering System . . . . . . . . . . . . . . . .132
Figure II-97 Hand Operated Rotary Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .133
Figure II-98 Motorized Rotary Filter with Single Blowdown Valve133
Figure II-99 Control Panel Hook-up for One Valve Blowdown VRS-2 Rotary Filter System . . . . . . . .133
Figure II-100 Control Panel Hook-up and Operation of Two Valve Blowdown VRS-2
Rotary Filter System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .134
Figure II-101 Motorized Rotary Filter with Three Valve Blowdown System for Viscous FLuids . . . . . . .134
Figure II-102 Freeze Proof Safety Shower with Antiscalding Protection . . . . . . . . . . . . . . . . . . . . . . . .135
Figure II-103 Automatic Contol of Smaller Compressor Cooling with Overheat Protection . . . . . . . . . .135
Figure II-104 Condensate Cooling System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .136
Figure II-105 Condensate Cooling and Flash Knockdown System . . . . . . . . . . . . . . . . . . . . . . . . . . .136
Figure II-106 Continuous Boiler Blowdown Cooling System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .137
Figure II-107 Controlling Coolant Flow to Vacuum Still Condenser and Draining Evaporator . . . . . . . .137
Figure II-108 Controlling Temperature of Ball Grinding Mill Jacket . . . . . . . . . . . . . . . . . . . . . . . . . . . .138
Figure II-109 Controlling Temperature of Oil Cooler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .138
Figure II-110 Controlling Temperature of Horizontal Solvent Condenser . . . . . . . . . . . . . . . . . . . . . . .138
Figure II-111 Controlling Temperature of Vertical Solvent Still . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .139
Figure II-112 Cooling Water Economizer for Multiple Rolls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .139
Figure II-113 Alternate Methods of Draining Compressed Air Receiver . . . . . . . . . . . . . . . . . . . . . . . .140
Figure II-114 Draining Compressed Air Dropleg to Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .140
Figure II-115 Draining Riser in Compressed Air Distribution Line . . . . . . . . . . . . . . . . . . . . . . . . . . . .140
Group Companies and Sales Offices
154
ArgentinaSpirax Sarco S.A.Ruta Panamericana Km. 24,9001611 Don TorcuatoBuenos Aires, ArgentinaAustraliaSpirax Sarco Pty. LimitedP.O. Box 6308Delivery CentreBlacktownN.S.W. 2148, AustraliaAustriaSpirax Sarco Ges.m.b.H.Eisgrubengasse 2/PF 41A-2334 Vosendorf-Sud.AustriaBelgiumSpirax Sarco N. V.Industriepark Zwijnaarde 59052 Gent - ZwijnaardeBelgiumBrazilSpirax Sarco Ind. E Com LtdaRodovia Raposo Tavares Km. 31Caixa Postal 14306700-000. Cotia S.P.Brazil
CanadaSpirax Sarco Canada Limited383 Applewood CrescentConcordOntario L4K 4J3, Canada
ChinaSpirax Sarco Engineering Co. Ltd.2nd Floor, Block 20, No:481Gui Ping RoadCaohejing Hi Tech ParkShanghai, China, Postcode 200233
ColombiaSpirax Sarco Internacional LtdaApartado Aereo 32484Cali (Valle)Colombia, South America
Czech RepublicSpirax Sarco Spol. s. r. o.V korytech (areal nakladoveho nadrazi CD)100 00 Praha 10 StrasniceCzech Republic
DenmarkSpirax Sarco LimitedBirkedommervej - 312400-Copenhagen N.V., Denmark
East AfricaSpirax Sarco Sales RepresentativeP.O. Box 38919NairobiKenya, East Africa
FinlandSpirax OySorvaajankatu 900810 Helsinki, Finland
FranceSpirax Sarco S.A.B P 61F 78193 TrappesCedex, FranceGermanySpirax Sarco GmbHPostfach 10 20 42D-78420 Konstanz, Germany
Hygromatik Lufttechnischer Apparatebau GmbHLise-Meitner-StraBe 3D-24558 Henstedt-UlzburgGermanyGreat BritainSpirax Sarco LimitedHead OfficeCharlton House, CheltenhamGloucestershire, GL53 8ERGreat BritainHong KongSee SingaporeHungarySpirax Sarco Ltd.11-1143 BudapestZászlós u. 18.HungaryIndiaSpirax Marshall LimitedP.B. No. 29Bombay Poona RoadKasarwadiPune 411 034, IndiaIndonesiaSee SingaporeItalySpirax-Jucker S.r.l.Via Donat Cattin, 520063 Cernusco Sul Naviglio (MI)Milano, ItalyJapanSpirax Sarco Limited3rd Floor, Koyo Building1-10-17 Hamamatsu-choMinato-kuTokyo, JapanKoreaSpirax Sarco Korea Limited3rd-5th Floor, Jungwoo Building1552-8 Seocho-dongSeocho-kuSeoul 137-070, KoreaLebanonSpirax Sarco Resident EngineerP.O. Box 11-3052Beirut, LebanonMalaysiaSpirax Sarco Sdn Bhd25, Jalan PJS 11/1Bandar Sunway46150 Petaling JayaSelangor Darul EhsanWest MalaysiaMexicoSpirax Sarco Mexicana S.A. de CVApartado Postal 5287-KMonterrey NL64000 - MexicoNew ZealandSpirax Sarco LimitedP.O. Box 76-160Manukau CityAuckland, New ZealandNigeriaSpirax Sarco Sales RepresentativeCakasa Company Ltd.96 Palm Ave.P.O. Box 871Mushin Lagos NigeriaNorwaySpirax Sarco Limited (Norge)P.O. Box 471483 Skytta, Norway
PakistanSpirax Sarco Sales Representative2-C Gulistan-E-Zafar P.R.E.C.H.S.Near SMCHS Block BPostal Code 74400Karachi, PakistanPolandSpirax Sarco Sp. z o.o.Fosa 2502-768 Warszawa, PolandPortugalSpirax Sarco-Equipamentos
Industrias Lda.Rua Da Quinta Do Pinheiro, Lote 3Portela de Carnaxide2795 Carnaxide, PortugalRussiaSpirax Sarco Ltd.(Room 1401)4 Vozrozhdenija Str.198188 St. Petersburg, RussiaSingaporeSpirax Sarco Pvt. Limited464 Tagore AvenueUpper Thomson RoadSingapore 787833South AfricaSpirax Sarco (Pty) Ltd.P.O. Box 925Kempton Park 1620Transvaal, South Africa
SpainSpirax Sarco S.A.Sant Josep, 130Poligon El Pla08980 Sant Feliu de LlobregatSpain
SwedenSpirax Sarco ABVästberga Allé 60S-126 30 Haegersten, Sweden
SwitzerlandSpirax Sarco A. G.Gustav-Maurer-Str.98702 Zollikon, Switzerland
TaiwanSpirax Longbridge Limited6th FloorNo. 8, Lane 94, Tsao Ti WeiShen Keng HsiangTaipei CountyTaiwan, Republic of ChinaThailandSpirax Boonyium Limited9th Floor, Benjaporn Building222 Krungtep-kreetha RoadBangkapiBangkok 10240, Thailand
U.S.A.Spirax Sarco, Inc.Northpoint Park1150 Northpoint Blvd.Blythewood, SC 29016
Watson-Marlow Bredel Inc.220 Balladvale StreetWilmington, MA 01887
VenezuelaSpirax Sarco S.A.Apartado 81088Caracas 1080A, Venezuela