industrial plant engineering reviewer - complete.pdf

INDUTRIAL PLANT ENGINEERING

REVIEWER

(LECTURE)

Revision 0

2012

Prepared By:

Agerico U. Llovido – PME

CONTENTS

A. PUMPS

B. FANS ANDLOWERS

C. AIR COMPRESSORS

D. MACHINERY FOUNDATIONS

E. HEAT TRANSFER AND HEAT EXCHANGERS

F. REFRIGERATION

G. AIR CONDITIONING

H. COOLING TOWERS

I. DRYERS

J. EVAPORATORS

K. CONVEYORS

L. INDUSTRIAL PROCESSES

M. INSTRUMENTATION AND CONTROLS

N. METROLOGY

O. PIPING

P. FIRE PROTECTION SYSTEMS

Q. MATERIAL HANDLING

R. AC AND DC MACHINERY

A. PUMPS - LECTURE

1

1. Purpose of Pump

The purpose of a pump is to transfer a fluid from a region of low pressure to another region at the same or higher

pressure.

A pump is a machine that imparts energy into a liquid to lift the liquid to a higher level, to transport the liquid from

one place to another, to pressurize the liquid for some useful purpose, or to circulate the liquid in a piping system by

overcoming the frictional resistance of the piping system.

2. Classification of Pumps

2.1 Reciprocating

a. Direct-acting

b. Indirect-acting

2.2 Rotary

2.3 Jet

2.4 Centrifugal

3. Definitions

Total dynamic head or dynamic head – is the sum of the pressure and velocity heads at a given section stated in

units of feet of the fluid flowing.

Total dynamic suction lift – is applied to pumps handling cold water and is the reading of a manometer or vacuum

gage (converted to feet of the fluid flowing).

Net positive suction head (NPSH) – is the difference between the absolute dynamic pressure of the liquid measured

at the centerline of a pump and the saturation pressure corresponding to the temperature of the liquid at the same

point, all expressed ion terms of feet head of the fluid flowing. NPSH may also be defined as the pressure at the

pump suction flange, corrected to the pump centerline, that prevents vaporization of the water.

Developed head (DH) – is the difference between the sum of the absolute pressure head and velocity head (or

absolute dynamic head) at the outlet of the pump and the sum of the absolute pressure head and velocity head (or

absolute dynamic head) at the inlet, both corrected to the centerline of the pump and expressed in feet head of the

fluid.

Static head – is the height of the surface of water above the gauge point.

Pressure head – is the static head plus gauge pressure on the water surface plus friction head.

Velocity head – is the head required to produce a flow of the water.

Suction lift – the vertical distance in feet (meters) from the liquid supply level to the pump center line with the pump

physically located above the liquid level supply.

Suction head - the vertical distance in feet (meters) from the liquid supply level to the pump center line with the

pump physically located below the liquid level supply.

A. PUMPS - LECTURE

2

Static discharge head – the vertical distance in feet (meters)between the pump center line and the point of free

discharge on the surface of the liquid in the discharge tank.

Total static head – the vertical distance in feet (meters) between the liquid level of the supply and the point of free

discharge on the surface of the liquid in the discharge tank.

Friction head - the head required to overcome the resistance to flow in the pipe and fittings.

Total dynamic suction lift – is the static suction lift plus the velocity head at the pump suction flange plus the total

friction head in the suction pipeline.

Total dynamic suction head - is the static suction head minus the velocity head at the pump suction flange minus the

total friction head in the suction pipeline.

Total dynamic discharge head – is the static discharge head plus the velocity head at the pump discharge flange plus

the total friction head in the discharge line.

Capacity – is the rate of flow of fluid measure per unit time, usually gallons per minute (gpm) or liters per minute

(lpm).

Centrifugal pump – a pump in which the pressure is developed principally by the action of centrifugal force.

End suction pump – a single suction pump having its suction nozzle on the opposite side of the casing from the

stuffing box and having the face of the suction nozzle perpendicular to the longitudinal axis of the shaft.

In Line pump – a centrifugal pump whose drive unit is supported by the pump having its suction and discharge

flanges on approximately the same center.

Horizontal pump – a pump with the shaft normally in a horizontal position.

Vertical shaft turbine pump – a centrifugal pump with one or more impellers discharging into one or more bowls and

a vertical educator or column pipe used to connect the bowls to the discharge head on which the pump driver is

mounted.

Horizontal split-case pump – a centrifugal pump characterized by a housing which is split parallel to the shaft.

Booster pump – is a pump that takes suction from a public service main or private use water system for the purpose

of increasing the effective water pressure.

Submersible pump – is a vertical turbine pump with the pump and motor closed coupled and designed to be

installed underground, as in the case of a deepwell pump.

A. PUMPS - LECTURE

3

Static water level – the level, with respect to the pump, of the body of water from which it takes suction when the

pump is not in operation.

Pumping water level – the level, with respect to the pump, of the body of water from which it takes suction when

the pump is in operation.

Draw-down – the vertical difference between the pumping water level and the static water level.

4. Typical Pumping Installation

5. Head and Power Calculation

A. PUMPS - LECTURE

4

5.1 Continuity equation

ttanconsAVQ ==

ddss VAVAQ ==

5.2 Developed Head (DH)

Developed head (DH) = static head + pressure head + velocity head + friction head

( ) ( )fsfdsd

w

sdsd hh

g

VVppzzHDH ++

−+

−+−==

2

22

γ

Where:

zs is negative if the source is below pump centerline and

ps is negative if it is a vacuum.

5.3 Friction head

Darcy Equation

=

g

V

D

Lfhf

2

2

5.4 Water power

QHWP wγ=

5.5 Brake power (BP) and Pump efficiency (ηp).

p

WPBP

η=

BP

WPp =η

BP = WP + PL + PDF + PHL + PML

Where:

PL = power required to overcome leakage

PDF = power required to overcome disk friction

PHL = power required to overcome hydraulic losses

PML = power required to overcome mechanical losses

6. Characteristics of Reciprocating Pumps.

6.1 Piston displacement, VD.

Piston rod neglected

LSnDVD

2

42

=

π

Piston rod considered

( ) LSndDDVD

−+=

222

44

ππ

where:

D = inside diameter or bore.

d = piston rod diameter.

L = piston displacement or length of stroke.

A. PUMPS - LECTURE

5

S = strokes per minute.

N = number of cylinders.

6.2 Volumetric Efficiency, Ev

Volumetric efficiency – is the ratio of actual volume to the piston displacement.

D

vV

QE =

6.3 Slip

Slip – is one minus the volumetric efficiency.

vESlip −=1

6.4 Actual discharge.

AVQ =

( )slipVQ D −= 1

7. Characteristics of Centrifugal Pumps.

7.1 Specific speed – is defined as the speed in revolutions per minute at which a geometrically similar impeller

would operate to develop 1 ft of head when displacing 1 gpm.

43H

QNNs =

where:

Ns = specific speed, rpm

N = speed, rpm

Q = discharge, gpm

H = head, ft

7.2 Impeller Contours

a. Radial or conventional

b. Francis

c. Mixed flow

d. Axial flow

A. PUMPS - LECTURE

6

7.3 Range of Specific Speeds

Radial impellers have specific speeds up to about 3000 rpm, while Francis wheels go up to 4500 rpm. Mixed flow

impellers range from the specific speed of the Francis wheels to about 10,000; for Propeller types the range is

from 10,000 to 14,000 rpm.

7.4 Similar Pumps

43

2

22

43

1

11

H

QN

H

QN=

3

22

2

3

11

1

DN

Q

DN

Q=

where D is the impeller diameter.

7.5 Affinity Law

Affinity laws – these laws express the mathematical relationship and illustrate the effect of changes in pump

operating conditions or pump performance variables such as pump head, flow, speed, horsepower, and pump

impeller diameters at nearly constant efficiency.

Flow,

=

1

2

1

2

12D

D

N

NQQ

Head,

2

1

2

2

1

2

12

=

D

D

N

Nhh

Power,

3

1

2

3

1

2

12

=

D

D

N

NPP

a. Constant impeller diameter, variable speed

1

2

1

2

N

N

Q

Q=

2

1

2

1

2

=

N

N

H

H

3

1

2

1

2

=

N

N

P

P

A. PUMPS - LECTURE

7

b. Constant speed, variable impeller diameter

1

2

1

2

D

D

Q

Q=

2

1

2

1

2

=

D

D

H

H

3

1

2

1

2

=

D

D

P

P

7.6 Centrifugal Pumps in Parallel and Series Operations.

a. Parallel pumps – performance is obtained by adding the capacities at the same head.

b. Series pumps – performance is obtained by adding the heads at the same capacity.

8. Cavitation

Cavitation – is a two-stage phenomenon consisting of the formation of vapor cavities resulting from low

pressure and their collapse as they move out of the low-pressure into higher pressure regions. The higher pressure

region causing the vapor cavity to collapse can be immediately following the formation of the vapor cavity or some

distance downstream from the impeller inlet, depending on the downstream pressure conditions and the quantity

of vapor formed.

Net positive suction head (NPSH) – is the term used by the pump industry for describing pump cavitation

characteristics. NPSH is defined as the pressure (head) in excess of the saturation pressure of the fluid being

pumped. NPSH is expressed as NPSH A (available) and NPSHR (required).

NPSHA is the NPSH available or existing at the pump installed in the system.

NPSHR is a performance characteristic of a pump and is established through closed loop or valve suppression

tests conducted by the pump manufacturer.

Causes of Cavitation:

a. Low suction pressure

b. Low atmospheric pressure

c. High liquid temperature

d. High velocity

e. Rough surfaces and edges

f. Sharp bends

Bad effects of Cavitation:

a. Drop in capacity and efficiency

b. Noise and vibration

c. Corrosion and pitting

A. PUMPS - LECTURE

8

B. FANS AND BLOWERS - LECTURE

1

1. Definitions.

Fan – is a machine used to apply power to a gas to increase its energy content thereby causing it to flow or move.

Blower – is a fan used to force air under pressure which means resistance to gas flow is imposed upon discharge. F

Exhauster – is a fan used to withdraw air under pressure which means resistance to gas flow is imposed upon

suction

2. Common Uses of Fans.

Ventilation, air conditioning, force and induced draft service for boilers, dust collection, drying and cooling of

materials, cooling towers, heating, mine and tunnel ventilation, pneumatic conveying and other industrial process

work.

3. Basic Differences According to the ASME.

Pump – a machine which adds energy to a liquid.

Fan – a machine which adds energy to a fluid at a pressure rise equal to or below 1 psig.

Blower – a machine which add energy to a fluid at a pressure rise between 50 and 1 psig.

Compressor – a machine which add energy to a fluid at a pressure rise above 50 psig.

4. Basic Element of Fan Design.

a. Wheel or impeller – the rotating member.

b. Housing – stationary member provided with an intake opening (inlet) and a discharge opening (outlet).

5. Types of Fan.


2

6. Types of blades and performance curves used on centrifugal fans

7. Functions of Fans.

a. To move air or gases through distribution systems and apparatus required for conditioning of buildings.

b. For drying and cooling.

c. For pneumatic conveying.

d. For duct collection, separation and exhaust.

e. For mine and tunnel ventilation.

f. For forced and induced draft of steam-generating units.

8. Factors Affecting Fan Selection.

a. Quantity of gas (air) to be moved per unit time.

b. Estimated resistance and expected variations.

c. Amount of noise permitted.

d. Space available for the fan.

e. Economic implications.

9. Fan Performance and Design.

9.1 Fan capacity, Q – volume handled by a fan expressed in cubic meter per sec at fan outlet conditions.

AVQ =


3

where:

Q = volume flowrate measured at outlet, m3/s

A = fan outlet area, m2

V = velocity at outlet, m/s

9.2 Fan static pressure head, hs – the total pressure diminished by the fan velocity pressure.

a

wws

hh

ρ

ρ=

where:

hs = static pressure head, meters of air

hw = manometer reading, meters of water

ρw = density of water = 9.81 kN/m3 or 1000 kg/m3 or 62.4 lb/ft3.

ρa = density of air at standard conditions = 1.2 kg/m3/

Standard condition: 101.325 kPa (29.92 in Hg) and 21.1 C (70 F).

9.3 Fan velocity pressure head, hv – corresponds to the average velocity determination from the volume of air flow

at the fan outlet area.

g

Vh o

v2

2

=

where:

hv = velocity head, meters of air

Vo = velocity at outlet, m/s

g = acceleration due to gravity, 9.81 m/s2

9.4 Total pressure head , htotal – the rise of the pressure head from fan inlet to fan outlet.

vstotal hhh +=

9.5 Power output – is the power output of a fan developed based on total pressure.

totalaQhOutputPower ρ=

9.6 Static air power – air horsepower calculated from static pressure.

saQhPowerAirStatic ρ=

9.7 Static efficiency ηs – static air power divided by the shaft power.

PowerShaft

PowerAirStatics =η

9.8 Mechanical efficiency ηm – power output divided by the shaft power.

PowerShaft

OutputPowerm =η

10. Bernoulli’s Equation Applied to Fans.

Basic Assumptions:

a. Considering inlet and discharge static pressure.

b. Considering inlet and discharge velocities.

c. Constant temperature.


4

Total head = static pressure head + velocity head

g

VVpph

a

total2

2

1

2

212−

+−

=γ

g

VV

g

pph

a

total2

2

1

2

212−

+−

=ρ

( )g

VVhhh

a

wwwtotal

2

2

1

2

212−

+−

=ρ

ρ

P1 and hw1 is negative if below atmospheric pressure.

Where:

P1 and hw1 = inlet static pressure reading.

P2 and hw2 = discharge pressure reading.

ρw = density of water (10000 kg/m3).

ρa = density of air (1.2 kg/m3 at 101.325 kPa and 21.11 C).

V1 = inlet velocity, m/s.

V2 = outlet velocity, m/s.

g = acceleration due to gravity.

11. Fan Characteristics and Fan Laws

Fan characteristics – is the term for the variation in fan capacity or volume pressure, power requirement, and fan

efficiency, with degree of restriction or resistance to gas flow, at constant speed.

Fan Laws - three basic relationships between fan size, fan speed, and gas density which are the bases for predicting

full-size fan performance.

=

1

2

3

1

2

12N

N

D

DQQ

=

1

2

2

1

2

2

1

2

12ρ

ρ

N

N

D

Dhh

=

1

2

3

1

2

5

1

2

12ρ

ρ

N

N

D

DPP

For fan efficiency equal.

11.1 Variable fan speed – constant fan size, constant density

=

1

2

12N

NQQ

2

1

2

12

=

N

Nhh

3

1

2

12

=

N

NPP


5

11.2 Variable fan size – geometrically similar fans, constant density 3

1

2

12

=

D

DQQ

12hh =

2

1

2

12

=

D

DPP

11.3 Variable gas or air density – constant fan size and speed, constant system or point of rating

12QQ =

=

1

2

12ρ

ρhh

=

1

2

12ρ

ρPP

12. Fan Combinations

Fans in series – used to increase head with the same discharge.

12QQ =

21hhhtotal +=

Fans in parallel – used to increase discharge with the same head.

12

hh =

21QQQtotal +=

- End -

C. AIR (GAS) COMPRESSORS - LECTURE

1

1. Introduction

Air or Gas compressor - is a machine used to increase the pressure of air (or gas) by decreasing its volume.

2. Classification of air compressors.

2.1 Positive Displacement Compressors

Positive displacement compressors – are those in which successive volumes of air are confined within a closed

space and elevated to a higher pressure.

2.1.1 Reciprocating compressors – where the compressing and displacing element (piston or diaphragm) has a

reciprocating motion.

2.1.2 Screw (Helical or spiral lobe) compressors – are machines in which two intermeshing rotors, each in helical

configuration displace and compress the air.

2.1.3 Sliding-vane compressors – are machines in which axial vanes slide radially a rotor motor mounted

eccentrically within a cylindrical casing.

2.1.4 Two impeller straight-lobe compressors – are machines in which two straight, mating but non-touching

lobes impellers trap the air and carry it from intake to discharge.

2.2 Dynamic Compressors

Dynamic compressors – are rotary continuous-flow machines in which the rapidly rotating element accelerates

the air as it passes through the element, converting the velocity head into pressure, partially in the rotating

element and partially in stationary diffusers or blades.

2.2.1 Centrifugal compressors – where acceleration of the air is obtained through the action of one or more

rotating impellers.

2.2.2 Axial compressors – where acceleration of the air is obtained through the action of a bladed rotor, shrouded

at the blade ends.

3. Application of Air Compressors

3.1 Reciprocating compressors – for high-pressure, low-capacity applications.

3.2 Rotary compressors – for moderate (medium)-pressure, low-capacity applications.

3.3 Centrifugal compressors – for low-pressure, high-capacity applications.

4. Performance of Single-Stage, Single-Acting Reciprocating Compressor


2

4.1 Compression Process (1-2)

nnVpVp

2211=

1

2

1

1

1

2

1

2

−−

=

=

nn

n

V

V

p

p

T

T

where n = polytropic exponent, = k for isentropic process (k = 1.4 for air and n =1 for isothermal process.)

4.2 Piston Displacement, VD

smLNDV D

32

4

π=

where D = bore, m ; L = stroke, m; N = speed, rev/sec.

4.3 Capacity of compressors, V1’.

1

1

1p

RTmcapacitycompressorV

′==′

4.4 Volumetric Efficiency, ηv.

D

vV

V

volumentDisplaceme

capacityCompressor1′

==η

n

vp

pcc

1

1

21

−+=η

where c = clearance = (V1 – VD)/VD.

4.5 Mass of compresses air inside the cylinder, m’

clmmm +′=

where:

m = amount of air inside cylinder

mCL = clearance mass

Also,

( ) DDD VccVVV +=+= 11

( )( )vVcV η11

1 ′+=

( )[ ]

′+=

1

1

1

11

p

RTmc

p

mRTvη

( )[ ]mcm v′+= η1

4.6 Compressor Work (Power)

−

−

′=

−

11

1

1

211n

n

kp

p

n

VnpW

where p1 = suction pressure, kPaa; p2 = discharge pressure, kPaa


3

4.7 Brake Power

Brake power – is the power required to drive the compressor

Brake power = Compressor power / compressor efficiency

Compressor Power = Brake power x compressor efficiency

4.8 Piston Speed

Piston speed = 2LN m/s

4.9 Adiabatic Compressor Efficiency

Adiabatic compressor efficiency = isentropic work /actual fluid work

4.10 Ideal Indicated Power

Ideal indicated power = pmiVD

where: pmi = indicated mean effective pressure.

4.11 Transferred heat in the cylinder, Q

( )12

TTmcQ n −=

where:

−

−=

n

nkcc vn

1

For air cv = 0.72 kJ/kg.K

4.12 Free Air Capacity, Vo

mmo =

RT

pV

RT

Vp

o

oo =

=

T

T

p

pVV o

o

o

where:

p, V, T – actual or given conditions.

Po, Vo, To – standard conditions. If not given, use 14.7 psi, 68 F or 101.325 kPa, 20 C.

4.13 Probable actual volumetric efficiency, ηa.

=

1

1

1T

T

p

p o

o

a ηη


4

5. Double-acting, Single-stage Reciprocating Compressor

Piston Displacement

a. Piston rod neglected:

LNDVD

2

42

=

π

b. Piston rod considered:

( )LNdDLNDVD

222

44−+=

ππ

6. Two-Stage Reciprocating Compressor.

Ideal (Optimum) Conditions:

a. No pressure drop in intercooler

b. Perfect intercooling

c. Work in first stage = work in second stage

−

−=

−

−

−−

11

11

1

21

1

1

1n

n

x

n

n

x

p

p

n

nmRT

p

p

n

nmRT

x

x

p

p

p

p2

1

= or 21

pppx =

Compressor work:

−

−

′=

−

11

2

1

1

11n

n

xk

p

p

n

VnpW

Heat rejected in intercooler:

( )1

TTmcQ xp −=

n

n

xx

p

pTT

1

1

−

=

1

11

RT

Vpm

′=′


5

7. Three-Stage Reciprocating Compressor.

Wk1 = Wk2 = Wk3

For ideal conditions, pressure ratios are equal:

yx

yx

p

p

p

p

p

p2

1

==

( ) 31

2

2

1pppx =

( ) 312

21pppy =

Compressor work:

−

−

′=

−

11

3

1

1

11n

n

xk

p

p

n

VnpW

Heat rejected in intercooler:

( )1

2 TTmcQ xp −=

8. Performance of Centrifugal and Rotary Compressors


6

Compressor work:

−

−=

−

11

1

1

211n

n

kp

p

n

VnpW

- End -

D. MACHINERY FOUNDATIONS - LECTURE

1

1. Definitions

Foundation – is that part of structure which transmit the loads to the supporting material.

Monolithic Foundation – is a concrete foundation which is formed by pouring the entire concrete mixture

continuously at one time and allowing the structure to harden as a whole unit.

Grouting – a process of filling a small clearance between machine and foundation, after the machine is aligned and

leveled, by using a special hardening mixture.

2. Functions of Foundations.

2.1 Support the weight of the engine.

2.3 Maintain proper alignment with the driven machinery, and

2.4 Absorb the vibration produced by unbalanced forces created by reciprocating revolving masses.

3. Materials

The foundation should be concrete, of 1 part cement, 2 parts sand and 4 parts broken stone or gravel (50 mm max).

To produce 1 cu yd of concrete using 1:2:4 mixture, the following are needed: 6 sacks cement, 0.44 cu yd sand

and 0.88 cu yd stone. (To produce 1 m3 of concrete using 1:2:4 mixture, the following are needed: 7.8 sacks cement,

0.44 m3 sand and 0.88 m

3 stone).

For given properties of concrete mixture use

( )

w

cx

xSG

ratioVV

ρ

ρ=

4. Recommended Dimensions

4.1 The distance of the edges of the foundation from the bedplate must be 6 in (150 mm) to 12 in (300 mm) to

secure the bolts within the foundation.

4.2 The vertical distance from the floor or soil level to the top edge of the foundation must be around 6 inches (150

mm) as minimum depth.

4.3 The foundation depth maybe taken to be 3.2 to 4.2 times the engine stroke, the lower factor for well-balanced

multi-cylinder engines and higher factor got engines with fewer cylinders, or on less firm soil.


2

4.4 Foundations should be isolated from floor slabs or building footings at least 25 mm around its perimeter to

eliminate transmission of vibration. Fill openings with watertight mastic.

5. Weight of Foundation

5.1 The minimum weight required to absorb vibration could be expressed as a function of the reciprocating masses

and the speed of the engine. However, for practical purposes it is simpler to use the empirical formula.

NWeWEF

××=

where :

WF = weight of foundation, kg

WE = weight of the engine, kg

e = empirical coefficient from PSME Code 2008, page 13. If not given and no table available, use e = 0.11.

5.2 Foundation mass should be from 3 to 5 times the weight of the machinery it is supposed to support.

5.3 In computation 2,406 kg/m3 or 150 lb/ft

3 may be used as weight of concrete.

6. Volume of Concrete Foundation.

If the weight and speed of the engine are not known, the volume of concrete for the foundation may be estimated

by the following data from PSME Code 2008, page 13.

7. Bearing Pressure

The first objective is achieved by making its supporting area sufficiently large. The safe loads vary from 4,890

kg/m2 for alluvial soil or wet clay to 12,225 kg/m3. (The latter is assumed to be a safe load average).


3

The weight of the machine plus the weight of the foundation should be distributed over a sufficient soil area

which is large enough to cause a bearing stress within the safe bearing capacity of the soil with a factor of safety of

five (5).

Knowing the bearing capacity of the soil, solve for the base width “b”. For machine foundation use only ½ of the

given safe soil bearing capacity,

bL

WW

A

WWSFE

b

FEb+

=+

=2

Then compute the depth of the foundation “h”.

hLba

VF

+=

2

Make adjustment in the dimensions if necessary provided that the required volume is maintained and without

reducing base area.

8. Steel Bar Reinforcement

Concrete foundations should have steel bar reinforcements placed both vertically and horizontally, to avoid thermal

cracking. Weight of reinforcing steel should be from ½% to 1 of the weight of foundation.

9. Foundation Bolts

Foundation bolts of specific size should be used and surrounded by a pipe sleeve with an inside diameter of at

least three (3) times the diameter of the anchor bolt and a length of at least 18 times the diameter of the bolt. No

foundation bolts shall be less than 12 mm diameter.

To prevent pulling out of the bolts when the nuts are tightened, the length embedded in concrete should be

equal to at least thirty (3) times the bolt diameter. The upper ends are surrounded by a 50 mm or 75 mm sheet

metal pipe, 460 mm to 610 mm long to permit them to bend slightly to fit the holes to the bedplate.

- End

E. HEAT TRANSFER AND HEAT EXCHANGERS- LECTURE

1

1. Definitions.

Heat – is defined as energy in transition due to a temperature difference.

Heat exchanger – is any device which effects a transfer of heat from one substance to another.

Heat exchanger – the equipment used to implement heat exchange between two flowing fluids that are at different

temperatures and separated by a solid wall.

Examples: boilers, evaporators, economizers, superheaters, condensers, coolers and heaters.

Heat transfer – is the term applied to a study in which the details or mechanisms of the transfer of energy in the

form of heat are of primary concern.

Hear transfer - is energy in transit, which occurs as a result of a temperature gradient or difference.

2. Modes of Heat Transfer.

2.1 Conduction – when the transition takes place because of contact of the particles of one or more bodies.

Conduction – is the transmission of heat through a substance without perceptible motion of the substance itself.

2.2 Convection – when the energy is transferred because of the motion or mixing of the particles of a fluid.

Convection – is the term applied to heat transfer due to bulk movement of a fluid.

Free convection – the substance moves because of the decrease in its density which is caused by increase I n

temperature.

Forced convection – the substance moves because of the application of mechanical power such as that of a fan.

2.3 Radiation – when all matters receive or reject energy to some degree as a wave motion.

Radiation – is the transfer of energy by electromagnetic radiation having a defined range of wavelengths.

3. Fourier’s Law of Conduction:

dx

kdt

A

Q−=

Fourier’s law: “the heat flux resulting from thermal conduction is proportional to the magnitude of the temperature

gradient and opposite to it in sign.

4. Conduction through Plane Wall.

( )x

ttkAQ

ba −=

Where:

Q = heat transmitted, W

A = heat transfer area, m2

ta = surface temperature on hot side, C

tb = surface temperature on cold side, C


2

k = thermal conductivity, W/m-C

5. Conduction through Composite Plane Wall.

( )

1

1

x

ttAkQ ba −

=

( )

2

2

x

ttAkQ cb −

=

Where:

k1 = thermal conductivity of first layer.

k2 = thermal conductivity of second layer.

A = heat transfer area which is common to both layers.

6. Heat Transfer from Fluid to fluid.

( )attAhQ −=11

( )22

ttAhQ d −=

Where:

h1 = surface film conductance on the hot side, W/m2-C.

h2 = surface film conductance on the cold side, W/m2-C.

( )( )

21

23

3

2

2

1

1

1

21

11ttUA

hk

x

k

x

k

x

h

ttAQ −=

++++

−=


3

23

3

2

2

1

1

1

11

1

hk

x

k

x

k

x

h

U

++++

=

where:

U = overall conductance or overall coefficient of heat transfer, W/m2-C.

7. Conduction Through Pipe

( )

1

2

2

r

r

ttkLQ ba

ln

−=

π

where:

L = length of pipe.

8. Conduction Through Composite Pipe.

( )

1

2

12

r

r

ttLkQ ba

ln

−=

π

( )

2

3

22

r

r

ttLkQ cb

ln

−=

π

( )( ) ( )

2

23

1

12

22

k

rr

k

rr

ttLkQ ca

lnln+

−=

π

where:

k1 = thermal conductivity of inner pipe.

k2 = thermal conductivity of outer pipe.


4

L = common length of the pipe.

9. Heat Transfer from Fluid to Fluid through Pipe.

( )aii ttAhQ −=1

( )2

ttAhQ coo −=

Where:

hi = surface film conductance on the hot side, W/m2-C.

ho = surface film conductance on the cold side, W/m2-C.

Ai = 2πr1L

Ao = 2πr3L

( )( ) ( ) ( ) ( )

2121

2

23

1

12

21

1

22

1ttAUttAU

hALk

rr

Lk

rr

hA

ttQ ooii

ooii

−=−=

+++

−=

ππ

lnln

( ) ( )

oi

i

hr

r

k

rrr

k

rrr

h

U

3

1

2

231

1

1211

1

+++

=lnln

( ) ( )

oi

o

hk

rrr

k

rrr

hr

rU

1

1

2

233

1

123

1

3 +++

=lnln

Where:

Ui = overall conductance based on inside area.

Uo = overall conductance based on outside area.

10. Types of Heat Exchanger.

a. Concentric tube – counterflow and parallel flow.

b. Crossflow

c. Shell and tube – single-shell pass and double-tube pass, multipass and so on.


5

11. Methods of Heat-Exchanger Analysis.

a. Logarithmic mean-temperature-difference (LMTD) method.

b. Number-of-transfer-units (NTU) method.

12. Mean Temperature Difference.

mtUAQ ∆=

a. Arithmetic mean temperature difference.

Arithmetic 2

BAm

ttt

∆+∆=∆

b. Logarithmic (True) mean temperature difference.

Logarithmic

B

A

BAm

t

t

ttt

∆

∆

∆−∆=∆

ln

13. Heat Balance

( ) ( ) myxpxyxyp tUAttcmttcmQ ∆=−=−=121212


6

14. Film Coefficient

Film coefficient , h – is a function of a characteristic dimension of the containing surfaces D, the density of the fluid

ρ, the conductivity of the fluid k, the velocity of the fluid V, the absolute viscosity µ, the specific heat of the fluid (at

constant pressure in case of a gas) cp, and the length L of the pipe or duct in which flow and transfer of heat occurs.

15. Dimensionless Numbers

Re – Reynolds number

µ

ρVD=Re

Nu – Nusselt number

k

hDNu =

Pr – Prandtl number

k

cpµ=Pr

St = 1/Pr – Stanton number

µpc

kSt =

Gz – Graetz number

kL

mcGz

p=

Gr – Grashof number

2

23

µ

βρ tgDGr

∆=

16. Film Coefficient, Turbulent Flow Inside Pipe

For fluids being heated or cooled during turbulent flow inside pipes of internal diameter D, 4080

0230

..

.

b

p

bb

i

k

cDV

k

Dh

=

µ

µ

ρ

For limits: 0.7 < Pr < 120; 10,000 < Re < 120,000 for high viscosity liquids; Re > 2100 for low viscosity liquids and

gases; L/D > 60; moderate ∆t.

Where subscript b indicates that the properties k, µ, and ρ should evaluated at the bulk temperature , and hi is the

inside film coefficient.

Close approximation for gases and vapors, Re > 2100.

80

80

02100210.

.

Re.. =

=

bb

i DV

k

Dh

µ

ρ


7

17. Film Coefficient, Laminar Flow of Liquids in Pipes.

McAdams equation for small D and small ∆t, fluid being heated. For viscous liquids, Re < 2100; mcp/(kL) >10.

31140

022

b

p

w

b

b

i

kL

mc

k

Dh

=

.

.µ

µ

where:

m = mass flow rate per unit time.

µw = viscosity of the fluid measured at the temperature of the inside wall of the pipe.

L = heated length of a straight pipe.

cp = specific heat of the liquid.

Sieder and Tate film coefficient h for laminar flow of liquid in a pipe.

140333033303330

861

....

.

=

s

pi

L

D

k

cDV

k

Dh

µ

µµ

µ

ρ

In dimensionless groups

1403330

33303330861

..

..PrRe.

=

sL

DNu

µ

µ

where:

µs = viscosity of the fluid measured at the inside pipe surface temperature.

18. Film Coefficients for Annular Space.

nNu PrRe. .80

0230= or

n

b

pe

k

cVD

k

hD

=

µ

µ

ρ80

0230

.

.

where: n = 0.4 for heating and n = 0.3 for cooling.

De = equivalent diameter which is four times the hydraulic radius.

The hydraulic radius is the sectional area of the stream divided by the wetted perimeter.

12

12

2

1

2

244

4 DDDD

DDDe −=

+

−=

ππ

ππ

19. Film Coefficients for flow over outside of a Single Pipe, Forced Convection. (McAdams)

60

240

.

.

=

f

o

f

o VD

k

hD

µ

ρ

where:

000501000 ,<<f

oVD

µ

ρ

2

wbf

ttt

+=


8

Do = outside diameter.

tb = the bulk temperature.

tw = the temperature of the pipe wall on the side whose film temperature is desired.

20. Film Coefficients with Free Convection. (McAdams)

The form of equation applicable to many problems in free convection is

m

f

p

ff

c

k

ctgDC

k

Dh

∆=

µ

µ

βρ2

23

where the subscript f indicates that the properties of the fluid are evaluated at the film temperature, C and m are

dimensionless constants, b is the coefficient of thermal expansion ( = 1/T for ideal gases), and the other symbols

have the usual meanings.

Simplified equation for hot surface in atmospheric air,

a. Vertical plates over 1 ft high.

FhrftBtuthc −−∆= 2250270

..

b. Horizontal pipes and vertical pipes over 1 ft high.

FhrftBtuD

th

o

c −−

∆= 2

250

270

.

.

21. Film coefficient for Condensing Vapors on a surface.

Types of condensation

a. Dropwise condensation – occurs when the vapor condenses as drops which are eventually removed from the

surface by gravity.

b. Film-type condensation – occurs when a vapor condenses and forms a liquid film over the cool surface, has

much lower film coefficient for steam than the former.

FhrftBtutND

ghkh

fo

fg−−

∆= 2

25023

7250

.

.µ

ρ

where N is the number of tubes in a vertical row of horizontal tubes.

22. Vaporization.

Types of Vaporization.

a. Film Boiling

b. Nuclear Boiling

23. Overall Heat Transfer Coefficient.

( )( )

( ) ( )

oi

o

hk

IDODOD

hID

ODU

1

2

1

++

=ln

24. Overall Heat Transfer Coefficient with scale coefficient.

( )( )

( )( )

( ) ( )

soosii

o

hhk

IDODOD

hID

OD

hID

ODU

11

2

1

++++

=ln

where hsi and hso is the scale coefficients.


9

25. Radiation.

Radiation – is a form of wave motion that obeys the same laws as other waves – light waves for example.

Radiation – is a heat transfer in which invisible electromagnetic waves are passed from one body to another through

space.

Reflectivity, ρ – is the fraction of the radiant energy reflected by a body.

Absorptivity, α – is the fraction of the radiant energy absorbed by the body.

Transmissivity, τ – is the fraction of the radiant energy transmitted through the body.

1=++ ταρ

Perfect black body – is any body that would absorb all the radiant energy it received.

Kirchhoff’s law – states that the ratio of the rate of emitting and absorbing energy is a constant for any body for a

given temperature and wave length.

Emissivity of any body – is the ratio of the rate of emission of radiant energy for that body to the rate of emission

for a perfect black body under the same conditions. Also called emittance ε.

Gray Body – is the actual body that radiates less heat than a black body.

26. Stefan-Boltzmann Law

The Stefan-Boltzmann law states that the amount of radiation from a black body is proportional to the fourth power

of the absolute temperature.

4ATQR σ=

where σ = 0.1713 x 10-8

is the Stefan-Boltzmann constant in Btu/ft2-R

4. In SI units it is 5.669 x 10-8 W/m

2-K

4.

27. Heat Transfer Between Two Black Bodies, Q.

( )4

1

4

2TTAQ −= σ

where

T1 = temperature of blackbody 1

T2 = temperature of blackbody 2

28. Heat Transfer Between Two Gray Bodies, Q.

( )4

1

4

2TTAFQ G −= εσ

where

ε = emissivity

FG = geometric view factor or configuration factor or angle factor or shape factor.

Configuration center – is the fraction of diffuse radiant energy that leaves one surface in space and directly strikes

another surface. Its value is based solely upon the manner in which the two surfaces are positioned.

- End -

F. REFRIGERATION - LECTURE

1

1. Definitions:

1.1 Reversed cycle – is a system that receives heat from a colder body and delivers heat to a hotter body, not in

violation of the second law, but by virtue of a work input.

1.2 Refrigeration – is to maintain a cold region at a temperature below the temperature of its surroundings.

1.3 Refrigeration – is defined as the process of extracting heat from a lower-temperature heat source, substance, or

cooling medium and transferring it to a higher-temperature heat sink.

1.4 Vapor compression systems – In vapor compression systems, compressors activate the refrigerant by

compressing it to a higher pressure and higher temperature level after it has produced its refrigeration effect.

The compressed refrigerant transfers its heat to the sink and is condensed to liquid form. This liquid refrigerant

is then throttled to a low-pressure, low temperature vapor to produce refrigerating effect during evaporation.

Vapor compression systems are the most widely adopted refrigeration systems in both comfort and process air

conditioning.

1.5 Absorption systems – In an absorption system, the refrigeration effect is produced by thermal energy input.

After absorbing heat from the cooling medium during evaporation, the vapor refrigerant is absorbed by an

absorbent medium. This solution is then heated by direct-fired furnace, waste heat, hot water, or steam. The

refrigerant is again vaporized and then condensed to liquid to begin the refrigeration cycle again.

1.6 Air or gas expansion systems – In an air or gas expansion system, air or gas is compressed to a high pressure by

mechanical energy. It is then cooled and expanded to a low pressure. Because the temperature of air or gas

drops during expansion, a refrigeration effect is produced.

1.7 Refrigerant – is the primary working fluid used for absorbing and transmitting heat in a refrigeration system.

Refrigerants absorb heat at a low temperature and low pressure and release heat at a higher temperature and

pressure.

1.8 Cooling medium – is the working fluid cooled by the refrigerant to transport the cooling effect between a central

plant and remote cooling units and terminals.

1.9 Liquid Absorbents – A solution known as liquid absorbent is often used to absorb the vaporized refrigerant

(water vapor) after its evaporation in an absorption refrigeration system. This solution, containing the absorbed

vapor, is then heated at high pressure. The refrigerant vaporizes, and the solution is restored to its original

concentration for reuse. Lithium bromide and ammonia, both in a water solution, are the liquid absorbents used

most often in absorption refrigerating systems.

2. Reversed Carnot Cycle


2

Heat Added = QA =Qin = TC∆s

Heat Rejected = QR = Qout = TH∆s

Coefficient of performance (Cooling):

CH

CAC

TT

T

W

QCOP

−==

Coefficient of performance (Heating):

CH

HRH

TT

T

W

QCOP

−==

Net work = W = QA – QR

3. Tons of Refrigeration.

Tons of refrigeration – is the amount of heat that must be extracted to freeze 1 ton of water at 32 F into ice at 32 F

(at 1 atm) in 1 day. Since the latent heat of fusion of water is closely 144 Btu/lb, we find (144)(2000) = 288,000

Btu/day = 12,000 Btu/hr.

4. Ideal Vapor Compression Cycle.

The cycle consists of the following series of processes:

Process 1–2: Isentropic compression of the refrigerant from state 1 to the condenser pressure at state 2.

Process 2–3: Heat transfer from the refrigerant as it flows at constant pressure through the condenser. The

refrigerant exits as a liquid at state 3.

Process 3–4: Throttling process from state 3 to a two-phase liquid–vapor mixture at 4.

Process 4–1: Heat transfer to the refrigerant as it flows at constant pressure through the evaporator to complete

the cycle.


3

4.1 Work of Compression

W = m(h2 – h1)

where:

m = refrigerant mass flow rate, kg/s

h1 = enthalpy entering compressor, kJ/kg

h2 = enthalpy leaving compressor, kJ/kg

4.2 Heat Rejected in the Condenser

QR = m(h2 – h3)

where:


h2 = enthalpy entering condenser, kJ/kg

h3 = enthalpy leaving condenser, kJ/kg

4.3 Quality of flash gas during throttling

h4 = h3

h4 = hf4 + x4hfg4

where:

h3 = enthalpy entering throttling device, kJ/kg

h4 = enthalpy leaving throttling device, kJ/kg

hf4 = enthalpy at saturated liquid conditions leaving throttling device, kJ/kg

hfg4 = latent heat at wet vapor conditions leaving throttling device, kJ/kg

x = quality or weight of flash gas per unit weight of refrigerant.

4.4 Refrigerating Effect

QA =m(h1 – h4)

where:


h1 = enthalpy entering evaporator, kJ/kg

h4 = enthalpy leaving evaporator, kJ/kg

In tons of refrigeration:

( )5163

41

.

hhmQA

−=

4.5 Coefficient of Performance

12

31

12

41

hh

hh

hh

hh

ncompressioofwork

effectingrefrigeratCOP

−

−=

−

−==

4.6 Power in kw per ton

ionrefrigeratofTons

powerCompressortonkw =


4

4.7 Volume Flow Rate at Suction

V1 = mv1

Where:


v1 = specific volume, m3/s

4.8 Displacement Rate of Compressor

LNDVD2

4

π=

where:

D = diameter of cylinder or bore, m

L = length of stroke, m

N = number of cycles completed per cycle

Note:

For single-acting compressor (makes one complete cycle in one revolution)

N = n

For double-acting compressor (makes two complete cycles in one revolution)

N = 2n

Where n is compressor speed.

4.9 Actual Volumetric Efficiency, ηva

D

vaV

V1=η

where:

V1 = volume flow rate at suction, m3/s

VD = volume displaced at suction, m3/s

4.10 Clearance volumetric efficiency, ηvc

−+=

−+=

2

1

1

1

211

V

Vcc

p

pcc

k

vcη

where:

c = percent clearance

for ammonia, use k = 1.4

4.11 Adiabatic compression efficiency, or simply efficiency, ηc

ncompressioofworkActual

ncompressioofworkIsentropicc =η

4.12 Mechanical efficiency, hm

BP

IP

powerBrake

powerIndicatedm ==η


5

5. Actual Vapor Compression Cycle

Actual vapor compression cycle - deviates from the ideal cycle primarily because of the inefficiency of the

compressor.

Possible Alternatives

1-2 Polytropic compression with friction and heat transfer.

2-3 Pressure drop at compressor discharge valve.

3-4 Pressure drop in delivery line.

4-5 Heat loss in delivery line.

5-6 Pressure drop in the condenser.

6-7 Liquid subcooling in condenser.

7-8 Heat gain in the liquid line.

8-9 Isenthalpic (or throttling) expansion.

9-10 Pressure drop in the evaporator.

10-11 Superheating of vapor in evaporator.

11-12 Heat gain in the suction line.

12-13 Pressure drop in the suction line.

13-14 Pressure drop due to wire drawing at the compressor suction valve.

6. Basic Components of Refrigeration System

6.1 Compressor – compresses the low-pressure refrigerant gas to a high-pressure refrigerant gas and cause to to

flow in the system.

6.1.1 Types of compressors:

a. Reciprocating compressor

b. Centrifugal compressor

c. Rotary compressor – vane type and screw-type

6.1.2 Classification of compressor based on enclosure.

a. Open-type compressor – whose crankshaft extends through the compressor housing so that a motor

can be externally coupled to the shaft.


6

b. Hermetically sealed compressor – a type in which the compressor and the motor are enclosed in the

same housing.

c. Semi-hermetic compressor – hermetically sealed compressor in which the cylinder head can be

removed for servicing of the valve and pistons.

6.2 Condenser – receives the high-pressure refrigerant gas and then condenses while rejecting heat to the cooling

medium which is either air or water.

6.2.1 Types of condensers used in refrigeration.

a. Air-cooler (Bare tube and finned tube).

b. Water-cooled (Shell-and-tube and shell-and-coil).

6.3 Throttling Device or Expansion Device – reduces the pressure of the refrigerant so that low temperature will be

attained; it also regulates the flow of refrigerant to the evaporator.

6.3.1 Functions of the Expansion Device

- To reduce the pressure of the liquid refrigerant from the condenser in order to attain low

temperature.

- To control the flow of the refrigerant to the evaporator.

6.3.2 Types of expansion Devices

6.3.2.1 Capillary Tubes

Inside diameter = 0.50 mm to 2 mm

Length = 1 m to 6 m

Capacity = up to 10 kw

6.3.2.2 Expansion Valves

- Gate valves

- Constant pressure expansion valves

- Thermostatic Expansion valves

- Thermostatic Expansion valves with external equalizer.

6.4 Evaporator – where the liquid portion of the refrigerant evaporates while absorbing heat from the surrounding.

Types of Evaporators

6.4.1 Dry-type compatible to all condenser types.

6.4.2 Flooded compatible to water-cooled condenser only (high-capacity system).

7. Refrigerants

7.1 Halocarbon refrigerants – contains one or more of the three halogens chlorine, fluorine and bromine.

R-11 CCl3F Trichloromonofluoromethane

R-12 CCl2F2 Dichlorodifluoromethane

R-13 CClF3 Monochlorotrifluoromethane

R-22 CHClF2 Monochlorodifluoromethane

R-40 CH3Cl Methyl Chloride

R-113 CCl2FCClF2 Trichlorotrifluoroethane

R-114 CClF2CClF2 Dichlorotetrafluoroethane

7.2 Inorganic refrigerants

R-717 NH3 Ammonia

R-718 H2O Water


7

R-729 Air

R-744 CO2 Carbon Dioxice

R-764 SO2 Sulfur Dioxide

7.3 Hydrocarbon refrigerants

R-50 CH4 Methane

R-170 C2H6 Ethane

R-290 C3H8 Propane

7.4 Azeotropes

Azeotropes – is a mixtures of two substances in which the components cannot be separated by distillation. (R-

502 is a mixture of 48.8% R-22 and 51.2% R-115).

8. Desirable Properties of Refrigerant

8.1 Thermodynamic Properties

a. Low freezing point

b. Low condensing pressure

c. Low evaporating pressure

d. Low power per ton

e. Low volume flow per ton

f. High COP

8.2 Chemical Properties

a. Non-toxic

b. Non-flammable

c. Non-corrosive

d. Not destructive to refrigerated products

8.3 Physical Properties

a. Low viscosity

b. High thermal conductivity

c. Easy leak detection

d. Miscible with oil

e. Reasonable cost

9. Refrigeration Cycle with Liquid Subcooling and/or Suction Vapor Superheating.


8

Advantages of subcooling:

a. Reduces quality of gas vapor.

b. Increases refrigerating effect of system.

How to employ subcooling?

a. Use of water subucoolers

b. Use of liquid refrigerant subcoolers – more expensive

10. Refrigeration Cycle with Liquid Suction Heat Exchanger

Heat Balance in the Heat Exchanger HE

mh3 + mh6 = mh1 + mh4

Purposes of the heat exchanger

a. To superheat the vapor going to the compressor, or to ensure pure vapor us entering the compressor.

b. To subcool the liquid from the condenser, thereby eliminating the flash gas.

11. Multi-Pressure Systems

These are refrigeration systems with two or more low-side pressures. Low-side pressure is defined as the refrigerant

pressure between expansion valve and compressor intake.

Intercooler – reduces the work per kilogram of vapor between two stages of compression; may be accomplished by

a water-cooled heat exchanger or by using a refrigerant.

Flash tank – equipment in which vapor is separated from the liquid.


9

a. Refrigeration system with Two-Stage Compressor

Compressor Work = (hx – h1) + (h2 – hy)

b. Refrigeration system with One Compressor serving Two (or more) Evaporators

By heat balance at junction

m1h6 + (m – m1)h8 = mh1

c. Refrigeration system with Two Evaporators and Two Compressors.


10

d. Refrigeration system with Flash Tank

By heat balance in Flash Tank:

mh4 = m1h5 + (m – m1)h7

By heat balance at junction:

m1h6 + (m – m1)h9 = mh1

12. Cascade Refrigeration Systems

These systems combine two-vapor compression units, with the condenser of the low-temperature system discharging

its heat to the evaporator of the high-temperature system.

12.1 Closed-cascade system – where fluids in the high pressure and low-pressure are separate and could be

distinct.


11

Heat Balance in the cascade condenser:

m1(h2 – h3) = m2(h5 – h8)

Compressor work = m1(h2 – h1) + m2(h6 – h5)

Refrigerating effect = m1(h1 – h4)

12.2 Direct-contact heat exchanger – where same fluid is used throughout the system.

Heat balance in the cascade condenser

m1(h2 – h3) = m2(h5 – h8)

Total compressor work = m1(h2 – h1) + m2(h6 – h5)

13. Air-Cycle Refrigeration System

Air-cycle refrigeration system – is operating on the reverse Brayton cycle, it is the only air-cooling process developed

commercially wherein a gaseous refrigerant is used throughout the cycle; an air cooler replaces the condenser and a

refrigerator takes the place of an evaporator whereas the expansion valve is substituted by an expansion engine or

turbine.

Types:

a. Closed or dense-air system

b. Open-air system

Schematic diagrams:

Closed or Dense-Air System


12

Open-air system

Processes:

1-2 reversible adiabatic (or isentropic) compression

2-3 reversible constant-pressure (or isobaric) heat rejection

3-4 reversible adiabatic (or isentropic) expansion

4-1 reversible constant-pressure (or isobaric) heat addition

Advantages:

a. Light in weight which makes it ideal in cooling aircraft.

b. It occupies less space as compared to vapor-compression systems.

Cycle Analysis:

a. Refrigerating effect or hear added in the refrigerant, QL

( )41

TTmcQ pL −=

where:

cp = constant-pressure specific heat; for air cp = 1.0062 kJ/kg-K.

b. Heat rejected in the air cooler, QR

( )23

TTmcQ pR −=

c. Work of compression in the compressor, WK

Isentropic work of compression


13

−

−=

−

11

1

1

211k

k

Kp

p

k

VkpW

Polytropic work of compression

−

−=

−

11

1

1

211n

n

Kp

p

n

VnpW

d. Work of compression in the expander, WE

Isentropic work of compression

−

−=

−

11

1

3

433k

k

Ep

p

k

VkpW

Polytropic work of compression

−

−=

−

11

1

3

433n

n

Ep

p

n

VnpW

e. Net work, Wnet

EKnet WWW −=

f. Coefficient of performance, COP

net

L

W

QCOP =

14. Other Methods of Refrigeration

14.1 Absorption refrigeration system (NH3 – H2O system).


14

14.2 Steam jet refrigeration.

15. Cold Storage

Brine – is water plus sodium chloride and/or calcium chloride mixture whose purpose of addition of impurities is to

decrease the fluid freezing temperature.

15.1 Heat load in Cold Storage Room

a. Heat conducted through the walls, ceiling and floor of the cold storage room.

b. Heat generated from the mechanical and electrical equipment.

c. Heat from the occupants.

d. Heat from infiltration and ventilation air.

e. Product heat load which is the largest load.

15.2 Heat released from the products (or commodities) in the Cold Storage Room

a. Sensible heat during cooling of products from entering temperature to freezing temperature (or cooling

above freezing).


15

b. Latent heat of fusion (or enthalpy of freezing).

c. Sensible heat during cooling of products below freezing.

d. Heat of respiration – applicably only for fruits and vegetables.

15.3 Total Heat Load, Qtotal

( ) ( )[ ] ( )HRmttcLHFttcmQ bsfaffebfbtotal +−++−=

where:

mb = brine mass flow rate

cbf = specific heat before freezing

caf = specific heat after freezing

te = entering temperature

tf = freezing temperature

ts = storage temperature

LHF = latent heat of fusion.

HR = heat of respiration

16. Ice Plant

16.1 Heat to be removed from water to produce ice, Q

( ) ( )[ ]iffaffwibfr ttcLHFttcmQ −++−=

where:

mr = refrigerant mass flowrate

cbf = specific heat of water before freezing, 4.187 kJ/kg-K or 1.0 Btu/lb-R

caf = specific heat of ice after freezing, 2.093 kJ/kg-K or 0.5 Btu/lb-R

tf = freezing temperature, 0 C or 32 F

twi = initial temperature of water, F

tif= ice final temperature, F

LHF = latent heat of fusion


16

16.2 Allowance for heat losses

Usually 10 to 20% of the heat to be removed; if not given, use higher value thus.

QQtotal 21.=

16.3 Empirical Equation for Freezing Time, in hours

bt

cxFT

−=

32

2

where:

c = empirical constant in the range of 5.75 to 7; if not given, use c = 7.0

x = average or mean thickness of ice block (ice cake), inches

Common in the Philippines, 300-lb ice block, mean x = 11 inches.

tb = brine temperature, F

16.4 Number of ice cans per ton of ice, N.

iceW

FTN

24

2000=

where:

FT = freezing time, hours

Wice = weight of ice block, lbs.

17. Units of Refrigerating Capacity

The standard unit of refrigeration is ton of refrigeration (or simply ton), denoted by the symbol TR.

In English units,

1 TR = 12,000 Btu/hr = 200 Btu/min

In Metric units

1 TR = 3,024 kcal/hr = 50.4 kcal/min

In SI units,

1 TR = 211 kJ/min = 3.516 kW

- End -

G. AIR CONDITIONING - LECTURE

1

1. Definitions

Air conditioning – implies the automatic control of an atmospheric environment either for the comfort of human

beings or animals or for the proper performance of some industrial or scientific process.

Psychrometry – is the science of involving thermodynamic properties of moist air and the effect of atmospheric

moisture on materials and human comfort.

Psychrometric chart – provide a graphical representation of the thermodynamic properties of moist air, various air

conditioning processes, and air conditioning cycles

Psychrometer – is the instrument used in the study of the properties of air.

Atmospheric air – is a mixture of many gases plus water vapor and countless pollutants.

Saturated air – air whose condition is such that any decrease in temperature will result in condensation of the water

vapor into liquid.

Moist air – is a binary mixture of dry air and water vapor.

Dry air – a non-condensing components of a mixture mainly nitrogen and oxygen.

Vapor – a condensable components of the mixture.

Unsaturated air – air containing superheated vapor.

Heating – is the transfer of energy to a space or to the air in a space by virtue of a difference in temperature

between the source and the space or air.

Humidifying – is the transfer of water vapor to atmospheric air.

Cooling – is the transfer of energy from a space, or air supplied to a space, by virtue of a difference in temperature

between the source and the space or air.

Dehumidifying – is the transfer of water vapor from atmospheric air.

Sensible heat factor – is the ratio of sensible to total heat, where total heat is the sum of sensible and latent heat.

Room sensible heat factor – is the ratio of room sensible heat to the summation of room sensible and room latent

heat.


2

Grand sensible heat factor – is the ratio of the total sensible heat to the grand total heat load that the conditioning

apparatus must handle, including the outdoor air heat loads.

Bypass factor – represents that portion of the air which is considered to pass through the conditioning apparatus

completely unaltered.

Effective room sensible heat factor – is the ratio of effective room sensible heat to the effective room sensible and

latent heats.

2. Functions of Air Conditioning

a. Control the temperature

b. Control the humidity

c. Control the purity, that is , removal of duct and other impurities

d. Control of air movement or circulation.

3. Moist Air Properties

3.1 Temperatures

Dry bulb temperatures (DB) – is the actual temperature of the air or the temperature of air as registered by an

ordinary thermometer.

Wet bulb temperatures (WB) – is the temperature of air if it is saturated or temperature of air as registered in a

wetted wick thermometer and exposed to a current of rapidly moving air.

Wet bulb depression – is the difference between the wet bulb and dry bulb thermometers.

Dew point temperature – it the temperature at which condensation of moisture begins when the air is cooled.

3.2 Dalton’s Law of Partial Pressure

vda ppp +=

where:

p = total mixture pressure.

pda = partial pressure exerted by dry air

pv = partial pressure exerted by water vapor.

3.3 Humidity Ratio (Specific Humidity or Moisture Content)

The humidity ratio of moist airW is the ratio of the mass of water vapour w

m to the mass of dry air am

contained in the mixture of the moist air, in lb/lb (kg/kg).

v

v

pp

pW

−=

6220.

For moist air at saturation:

s

ss

pp

pW

−=

6220.


3

where:

p = total pressure of air-water vapor mixture.

Pa = partial pressure of dry air.

Pv = partial pressure of water vapor.

3.4 Relative Humidity

The relative humidity φ of moist air, or RH, is defined as the ratio of the actual water vapor pressure of the air

to the saturated water vapor pressure of the air at the same temperature.

s

v

p

p=φ

3.5 Degree of Saturation (Percent Saturation)

The degree of saturation µ is defined as the ratio of the humidity ratio of moist air W to the humidity ratio of

the saturated moist air sW , at the same temperature and pressure.

φµ ≈=

pTsW

W

,

3.6 Enthalpy

The enthalpy h of a mixture of perfect gases is equal to the sum of the enthalpies of each constituents,

va Whhh +=

And for the air-water vapor mixture is usually referenced to the mass of dry air.

Enthalpy – a thermal property indicating the quantity of heat in the air above an arbitrary datum.

In English units. ( )FlbmBtucpa −= 2400. , ( )FlbmBtucpv −= 4440.

Enthalpy of saturated water vapour gi at 0 F is 1061.2 Btu/lbm.

( ) lbmaBtutWth 4440210612400 ... ++=

In SI units. ( )CkgkJcpa −= 01. , ( )CkgkJcpv −= 861.

Enthalpy of saturated water vapor gi at 0 C is 2501.5 kJ/kg.

( ) kgakJtWth 8613250101 ... ++=

3.7 Specific Volume (Moist Volume)

The moist volume of moist air v , ft3/lb (m

3/kg), is defined as the volume of the mixture of the dry air and water

vapour when the mass of the dry air is exactly equal to 1 lb (1 kg), that is,

am

Vv =

where, V = total volume of mixture, ft3 (m3).


4

am = mass of dry air, lb (kg).

Then,

( )

at

Ra

a P

WTR

m

Vv

607811 .+==

( ) ( )RlbmlbfftRa −−= 35253.

( )KkgJRa −= 287

3.8 Density

The air density aρ , in lb/ft3 (kg/m

3), is defined as the ratio of the mass of dry air to the total volume of the

mixture, i.e., the reciprocal of moist volume.

vV

ma

a

1==ρ

3.9 Specific Heat of moist air at constant pressure

The specific heat of moist air at constant pressure pac is defined as the heat required to raise its temperature 1

F (0.56 C) at constant pressure.

FlbBtucpa −= 2430.

KkgJcpa ⋅=1020

4. The Psychrometric Chart


5

5. Basic Psychrometric Processes.

0-1 Sensible Cooling

0-2 Heating (Dryer)

0-3 Humidifying (Isothermal dryer)

0-4 Dehumidifying

0-5 Cooling and Dehumidifying (Air conditioner)

0-6 Heating and Humidifying (Cooling tower)

0-7 Cooling and Humidifying (Adiabatic dryer)

0-8 Heating and Dehumidifying (Chemical Dehumidification).

6. Air Mixing

By heat balance:

m1h1 + m2h2 = (m1 + m2)h3

By moisture balance:

m1W1 + m2W2 = (m1 + m2)W3

By temperature balance (dry bulb):

m1T1 + m2T2 = (m1 + m2)T3


6

7. Applications of Psychrometry

a. Air conditioner

b. Cooling tower

c. Dryer

8. The Air Conditioner

Refrigerating Capacity = m(h1 – h2)

Rate of moisture removal = m(W1 – W2)

9. Air conditioning calculations


7

Conditioners:

a. Cooling and dehumidifying coils of a refrigerating system

b. Water chiller

c. Spray equipment

Sensible Heat Load

Qs = mscp(t2 – t1) kW

where:

cp = 1.0 kJ/kg.C

t1, t2 = dry bulb temperatures, C

Latent Heat Load

QL = ms(W2 – W1)hv kW

where:

hv = 2442 kJ/kg (average)

Total Heat Load

QT = Qs + QL = ms(h2 – h1) kW

Sensible Heat Ratio (or Factor)

Ls

s

QQ

QSHR

+=

Mixing of recirculated air and outside air before entering the conditioner.

moh3 + (ms – mo)h2 = msh4

Air conditioner capacity = ms(h4 – h1) kw

Recirculated air and outside air separately enter the conditioner.

Air conditioner capacity = mo(h3 – h1) + (ms – mo)(h2 – h1) kw

Ventilation load = mo(h3 – h1) kw

10. Methods of Handling the Air Supplied to a Conditioned Space.

a. 100% outside air (fresh air) – economical in areas whose outside conditions are close in temperatures and

humidity to the space conditions being maintained.


8

b. Outside air with recirculation – more economical than using all outside air since the recirculated air temperature

is closer to the conditioned space; impractical in areas where noxious odors arise.

c. Outside air with external bypass system – part of the recirculated air is controlled by damper action making it

bypass the conditioner.


1

1. Definitions

Cooling Tower – whose function is to reject heat to the atmosphere by reducing the temperature of water circulated

through condensers or other heat-rejection equipment.

Cooling Tower – is a device in which recirculating condenser water from a condenser or cooling coils is evaporatively

cooled by contact with atmospheric air.

2. Types of Cooling Towers

2.1 Atmospheric or natural draft

2.1.1 Deck type

2.1.2 Spray type

2.2 Mechanical draft

2.2.1 Forced draft

2.2.2 Induced draft

3. Schematic Diagram


2

4. Cooling Range

Cooling Range – is the difference between the entering and leaving water temperature.

Cooling range = ta – tb

5. Approach

Approach – is the difference in temperature between the cold water and the entering air wet bulb.

Approach = tb – twb

6. Cooling Tower Efficiency of Effectiveness.

Cooling efficiency – is the ratio of the actual cooling range to the theoretical cooling range.

Cooling efficiency = wba

ba

tt

tt

−

−

7. Make-up Water Requirement

By mass balance:

m1W1 + m3 = m1W2 + m4

m5 = m3 – m4 = m1(W2 – W1)

% make-up water = 3

5

m

m

FloorWaterofMass

WaterupMakeofAmount=

−

where:

m5 = make-up water requirement, kg/s

m1 = mass flow of air entering, kg/s

W1 = humidity ratio of air entering, kg/kg

W2 = humidity ratio of air leaving, kg/kg

m3 = mass flow of water entering, kg/s

m4 = mass flow of water leaving, kg/s

Energy Balance:

m1h1 + m3h3 + m5h5 = m1h2 + m4h4

where m5 = m3 – m4

m1h1 + m3h3 (m3 – m4)h5 = m1h2 + m4h4

Heat Balance:

Heat absorbed by air = Heat rejected by water

m1(h2 – h1) = m3cp(ta – tb)

where:

m3 = mass flow rate of water flowing, kg/s

cp = specific heat of water = 4.187 kJ/kg-C

8. Cooling Tower Specification

40-30-20 means than ta = 40 C, tb = 30 C and twb = 20 C.

- End -

I. DRYERS - LECTURE

1

1. Definitions

Hygroscopic Materials – are substances which are variable in the moisture content they can h old at different times.

Bone-dry weight (BDW) – is the final constant weight attained by any hygroscopic substance after being dried out or

no trace of moisture left.

Regain – the hygroscopic moisture content of a substance expressed as the ratio of the moisture weight to the bone

dry weight.

Gross weight – expressed as the sum of the moisture weight and bone-dry weight.

Gross weight = Moisture weight + Bone-dry weight

Moisture content – expressed as the ratio of the moisture weight to the gross weight.

Moisture content = Moisture weight / Gross weight

2. Dryer Calculation

Gross Weight = Bone-dry Weight + Moisture Weight

GW = BDW + MW

BDW of entering material = BDW of leaving material

GWA – MWA = GWB – MWB

Moisture removed from materials, mR

mR = MWA – MWB

Moisture removed by air = moisture removed from materials

mA(H4 – H3) = mR = MWA – MWB

I. DRYERS - LECTURE

2

34HH

MWMWm BA

A−

−=

where:

MWA = total moisture content at A, kgvapor/s

MWB = total moisture content at B, kgvapor/s

H4 = moisture content of air leaving dryer, kgvapor/kgdry air

H3 = moisture content of air entering dryer, kgvapor/kgdry air

mA = air mass flow rate, kgdry air/s

Considering the air preheater and ms = steam mass flow rate

Heat gained by the air = heat lost by the steam

mA(h2 – h1) = mshfg

( )

fg

As

h

hhmm 12

−=

3. Three Methods of drying based on heat transfer

3.1 Direct of convection drying

3.2 Indirect drying

3.3 Infrared or radiant heat drying

4. Types of dryers based on movement of materials

4.1 Continuous dryer

4.2 Batch dryer

5. Types of dryers based on heat source

5.1 Steam heated

5.2 Oil fired, coal fired

5.3 Electric

6. Classification of Dryers

6.1 Rotary Dryer – most commonly used dryer which consists of a rotating cylinder inside which the materials flow

while getting in contact with the hot gases; the cylinder is tilted at a slight angle and fitted with lifting flights;

used for copra, sand, wood chips.

6.2 Tower Dryer – consist of a vertical shaft in which the wet feed is introduced at the top and falls downward over

baffles while coming in contact with the hot air which rises and exhausts at the top; used for palay, wheat,

grains.

6.3 Hearth Dryer – a type of dryer in which the material to be dried is supported on a floor through which the hot

gases pass; used for copra, coal, enamel wares.

6.4 Centrifugal Dryer – consists of centrifuge revolving at high speeds causing the separation, by centrifugal force, of

the water from the material; used for drying fertilizer, salt, sugar.

6.5 Tray Dryer – consists of trays, carrying the materials to be dried, placed in compartment or moving conveyor;

used for ipil-ipil leaves, grains.

6.6 Infrared Ray Dryer – consists of infrared lamps in which the rays are directed to the articles to be dried; use for

during painted articles like cars.

- End -

J. EVAPORATORS - LECTURE

1

1. Definition

Evaporators – are used either to remove the water from a liquid substance, like sugar juice, or to produce distilled

water by condensing the steam.

2. Three Principal Types of Evaporators according to construction.

2.1 Horizontal tube evaporator – consist of vertical horizontal cylindrical body; two rectangular steam chests in the

lower section contain tube sheets; primarily suitable for non-viscous liquids that do not deposit salt or scale

during evaporation.

2.2 Standard vertical tube evaporator – consists of vertical cylindrical shell with flat, dished or conical bottom; most

widely used type; can be used for liquids that deposit salt or scale during evaporation.

2.3 Long-tube, natural-circulation vertical evaporator – consists of long tubes so that the liquor passes through the

evaporator but once, used with non-salting or non-scaling liquids; can be used with high viscosities; one of the

cheapest types.

3. Multiple Effect Evaporator

A series of evaporators so connected that the vapor from one body is used as the heating steam in the next.

Types of Multiple Effect (Multi-Stage) Evaporator:

a. Parallel feed

b. Backward feed

c. Forward feed

d. Mixed feed

4. Two Styles of Evaporators

a. Film type – where a spray of water falls on tubes that are kept at a high temperature by motivating steam on the

inside.

b. Submerged type – where the tube bundle is submerged in the liquid.

5. Relieving Rate or Disengaging Rate

Relieving rates – can be given as the velocity at which the vapor leaves the water surface.

Relieving surface – is defined as the width of the water surface in the shell times the distance between the tube

sheets.

Disengaging area = Relieving surface = weight of vapor per sec x specific volume / velocity

J. EVAPORATORS - LECTURE

2

6. Parallel and Series Evaporator Arrrangement

7. Series (Forward Feed) Arrangement Evaporators

Effect – each evaporator when in arranged in series.

First Effect – the first evaporator in the chain.

Second Effect – the second evaporator in the chain. Etc.

Heat Head – is defined as the difference between the saturation temperature of the motivating fluid and the

saturation temperature of the vapor.

Energy Balance:

For 1 lb of steam entering the first effect.

( )

w

ds

hh

hhW

−

−=

1

1

1

1

For W1 lb of steam entering the second effect.

( )

w

d

hh

hhWW

−

−=

2

211

2

And so on..

Raw water required per steam evaporated = W1 + W2

- End -

K. CONVEYORS - LECTURE

1

1. Definition

Conveyors – are defined as either fixed or portable devices for moving materials between two fixed points at the

same or different elevations, with continuous or intermittent forward movement.

2. Types of Conveyors

2.1 Belt Conveyors – continuous system; belt usually troughed; high capacities possible.

2.2 Spiral Conveyors – endless helicoids screw in a trough. Can easily be made dust-tight. Not having a return strand,

it required a minimum of space. Limited in length. Considerable wear.

2.3 Flight or Scraper Conveyors – low in first cost but having large energy consumption. There is considerable wear,

caused by abrasion.

2.4 Pivoted Bucket Carriers – material is carried and buckets are supported on rollers which reduce friction to a

minimum. The pivoted bucket carries can both elevate and convey. Since it is run at low speed, the operation is

both silent and free from vibration.

2.5 Larries – suspended rail types are generally used because even though they require more headroom than the

floor type, they leave the boiler aisle free from obstruction.

3. Belt Conveyors

Belt conveyors – is probably more universally used than any other. The first cost is reasonable and the power

consumption is low. It is widely used for horizontal movement of coal and, to a certain extent, for inclined runs.

Let

P1 = pull to move the weight of material on loaded run

P2 = pull to move conveyor parts on loaded run

P3 = pull to move conveyor parts on empty run

P = total chain pull = P1 + P2 + P3

Power = Total Chain Pull x Velocity

- En d -

L. INDUSTRIAL PROCESSES - LECTURE

1

1. Flow Diagram or Flow Sheet

Flow Diagram – is a diagram showing the flow of materials through the various equipment or processes involved in

the manufacture of a certain product.

a. Process flow diagram – indicates only the processes involved, drawn in block diagrams.

b. Equipment flow diagram – shows the various equipment used in the processing.

c. Equipment-Process flow diagram – combines the equipment and processes in the diagram.

2. Industries in the Philippines

Sugar manufacturing (raw and refined sugar)

Cement manufacturing (wet and dry process)

Rice and corn milling

Pulp and paper manufacturing

Plywood manufacturing

Glass manufacturing

Beer manufacturing

Copper milling

Steel manufacturing

Coconut oil milling

Fertilizer manufacturing

Flour milling

3. Foundry Equipment

3.1 Melting furnaces used in foundry

a. Crucible furnace – suitable for non-ferrous metals; the metal is melted inside a crucible heated by an oil-

fired burner.

b. Cupola furnace – for melting iron; the heat comes from coke burning inside the cupola itself.

c. Induction furnace – for ferrous and non-ferrous metals, uses electric current for melting the scraps or ingots.

3.2 Methods of casting used in foundry

a. Sand casting

b. Pressure die casting

c. Metal mold casting

d. Centrifugal casting

e. Plaster mold casting

- End -

M. INSTRUMENTATION AND CONTROLS - LECTURE

1

1. INSTRUMENTATION

Instrumentation – refers to a collection of instruments for the purpose of observation, measurement and controls.

Instruments – are devices used directly or indirectly to measure and/or control a variable.

2. Definitions

Accessible – a term applied to a device of a function that can be used or be seen by an operator for the purpose of

performing control actions, e.g., set point changes, automatic-manual transfer, or on-off actions.

Alarm – a device or function that signals the existence of an abnormal condition by means of audible or visible

discrete change, or both, intended to attract attention.

Assignable – a term applied to a feature permitting the channeling (or direction) of a signal from one device to

another without the need for switching, patching, or changes in wiring.

Auto-Manual Station – synonym for control station.

Balloon – synonym for bubble.

Behind the Panel – a term applied to a location that is within an area that contains (1) the instrument panel, (2) its

associated rack-mounted hardware, or (3) is enclosed with the panel.

Binary – a term applied to a signal or device that has only two discrete positions or states.

Board – synonym for panel.

Bubble – the circular symbol used to denote and identify the purpose of an instrument or function. It may contain a

tag number.

Computer device – a device or function that performs one or more calculations or logic operations, or both, and

transmits one or more resultant output signal. A computing device is sometimes called the computing relay.

Configurable – a term applied to a device or system whose functional characteristics can be selected or rearranged

through programming or other methods. The concept excludes rewiring as a means of altering the configuration.

Controller – a device having an output that varies to regulate a controlled variable in a specified manner. A

controller may be a self-contained analog or digital instrument, or it may be the equivalent of such an instrument in

a shared-control system.

Control station - a manual loading station that also provides switching between manual and automatic control

modes of a control loop. It is also known as an auto-manual station.


2

Control valve – a device, other than a common, hand actuated ON-OFF valve or self-actuated check valve, that

directly manipulated the flow of one or more fluid process streams.

Converter – a device that receives information in one form of an instrument signal and transmits an output signal in

another form.

Digital – a term applied to a signal or device that uses binary digits to represent continuous valve or discrete states.

Distributed Control System – a system which, while being functionally integrated, consist of subsystems which may

be physically separate and remotely located from one another.

Final Control Element – the device that directly controls the value of the manipulated variable of a control loop.

Often the final control element is a control valve.

Function – the purpose of, or an action performed by a device.

Identification – the sequence of letters of digits, or both, used to designate an individual instrument or loop.

Instrument – a device used directly or indirectly to measure and/or control a variable.

Instrumentation – a collection of instruments or their application for the purpose of observation, measurement,

control, or any combination of these.

Local – the location of an instrument that is neither in nor on a panel or console, nor it is mounted in a control

room.

Local Panel – a panel that is not a central or main panel. Local panel are commonly in the vicinity of plan subsystems

or sub-areas.

Loop – a combination of two or more instruments or control functions arranged so that signal pass from one to

another for the purpose of measurement and/or control of a process variable.

Manual Loading System – a device or function having a manually adjustable output that is used to actuate one or

more remote devices

Measurement – the determination of the existence or the magnitude of the variable.

Monitor – a general term for an instrument or instrument system used to measure or sense the status of magnitude

of one or more variables for the purpose of deriving useful information.

Monitor light – synonym for pilot light.


3

Panel – A structure that has a group of instruments mounted on it, houses the operator-process interface, and is

chosen to have a unique designation.

Panel-Mounted – a term applied to an instrument that is mounted on a panel or console and is accessible for an

operator’s normal use.

Pilot Light – a light that indicates which of a number of normal conditions of a system or device exists.

Primary Element – synonym for sensor.

Process – any operation or sequence of operations involving a change of energy, state, composition, dimension, or

other properties that may be defined with respect to a datum.

Process Variable – any variable property of a process.

Program – a repeatable sequence of actions that defines the status of outputs as a fixed relationship to a set of

inputs.

Programmable Logic Controller – a controller, usually with multiple inputs and outputs, that contains an alterable

program.

Relay – a device whose functions is to pass on information in an unchanged form or in some modified form.

Scan – to sample, in a predetermined manner, each of a number of variables intermittently.

Sensor – that part of a loop of instrument that first senses the value of a process variable, and that assumes a

corresponding, predetermined, and intelligible state or output.

Set Point – an input variable that sets the desired value of the controlled variable.

Shared Controller – a controller, containing programmed algorithms that are usually accessible, configurable, and

assignable.

Shared Display – the operator interface device (usually a video screen) used to display process control information

from a number of sources at the command of the operator.

Switch – a device that connects, disconnects, selects, or transfers one or more circuits and is not designated as a

controller, a relay, or a control valve.

Test Point – a process connection to which no instruments is permanently connected.


4

Transducer –a general term for a device that receives information in the form of one or more physical quantities,

modifies the information and/or its form, if required, and produces a resultant output signal.

Transmitter – a device that senses a process variable through the medium of a sensor and has an output whose

steady-state value varies only as a predetermined function of the process variable.

- End -

N. METROLOGY - LECTURE

1

1. Definition

Metrology – concerns with the fundamental standards and techniques of measurements, and with the scientific

principles of the instrumentation involved.

Correctness / Accuracy – degree of conformity of a measured or calculated value to some recognized standard or

specific value.

Error of measurement – the difference between the measured and true value.

Precision – is the repeatability of the measuring process, or how well identically performed measurement agree,

which concept applies to a set of measurements.

Tolerance - is the amount of variation permitted in the part of total variation allowed in a given dimension.

Allowance – is the minimum clearance space intended between the mating parts and represents the conditions of

tightest possible fit.

Standard – something that is set up and established by authority as a rule for the measure of quantity, weight,

extent, value or quality.

Sensitivity – is the ability of a measuring device to detect small differences in a quality being measured.

Readability – is the susceptibility of a measuring device to having its indication converted to a meaningful number.

2. Common Measuring Instruments

Physical Quantity Measured Instrument Used

Pressure Bourdon pressure gauge

Compound gauge

Vacuum gauge

Manometer

Draft gauge

Barometer

Temperature Mercurial thermometer

Bi-metallic thermometer

Thermocouple

Radiation pyrometer

Optical pyrometer

Weight Platform balance


2

Spring balance

Analytical balance

Beam balance

Pendulum scale

Density; specific gravity Hydrometer

Pycnometer

Westphal balance

Heating value of fuel Bomb calorimeter

Gas calorimeter

Viscosity Viscosimeter

Area of irregular plane figures Planimeter

Rotational speed Tachometer

Centrifugal, vibration, electric

Stroboscope

Vibration intensity and frequency Vibrometer

Linear speed Speedometer

Distance travelled by a vehicle Odometer

Velocity of flow Velometer

Flow rate Rotameter

Anemometer

Flowmeter

Indicated power Engine indicator

Brake power Dynamometer

a. Absorption dynamometer

Prony brake

Water brake

b. Transmission dynamometer

Electric dynamometer

Electric cradle dynamometer


3

Analysis of flue gas Orsat apparatus (Gas analyzer)

Quality of steam Steam calorimeter

-throttling, separating, condensing barrel, electric

Dry Bulb and Wet Bulb Temperature of air Psychrometer

- Sling, aspiration

Moisture content (humidity) of air Hygrometer

Relative humidity of air Humeter

Hardness of steel Brinell Hardness tester

Rockwell hardness tester

Vickers hardness tester

Surface roughness Profilometer

Angle Protractor

Linear distance (thickness, depth, etc.) Rule, depth gauge, vernier caliper, micrometer caliper

Inaccuracy in alignments, eccentricities Dial indicator

Space clearance, gap Feeler gauge

3. Graduated Manual Measuring Tools

Rules – the most generally used graduated measuring instrument in the industrial metrology field for approximately

determining linear dimensions.

Shrink Rules – commonly employed in the pattern-making trade where the casting of metals are involved.

Hook Rule – frequently used to assure the user that the end of the workpiece is flush with the end of the rule.

Tapered Rules – used in measuring inside of small holes, narrow slots, and grooves.

Slide Calipers – consist of a stationary integral with graduated beam on which the movable jaws slides, with a

reference point for inside and outside reading.

Vernier Caliper – a measuring instrument which can be used for taking both inside and outside dimension.

Dial Caliper – directly reading calipers which are accurate up to the thousandth of a centimeter.


4

Vernier Height Gages – vertically-positioned vernier calipers used in tool rooms, inspection departments, or

wherever layout and jig and fixtures work necessitate accurately measuring or marking off vertical distances.

Vernier Depth Gages – provide long range accuracy for determining the depths of holes, slots, and recesses as well

as measuring from a plane surface to toolmaker’s buttons in locating center distances.

Gear Tooth Vernier Calipers – use to check the pitch line thickness of gear teeth by measuring the tooth chord at a

specific distance (chordal addendum) from the top of the gear tooth.

Micrometer Calipers – most useful close tolerance measuring devices for quick and accurate measurements to the

thousandth part of a centimeter.

Outside Micrometer – precision measuring instrument used in determining outside measurements.

Direct Reading Micrometers – are read directly in thousandths from figures appearing in small windows on the

barrel of the micrometer.

Blade Type Micrometer – are an adaptation of standard micrometers in which the anvil and spindle ends are thinned

to a blade shape which are used for checking the root diameter of circular form tools as well as the diameter and

depth of narrow slots, keyways, recesses, etc.

Quick Adjusting Micrometers – allow spindle to be slid quickly to any point within their range which makes them

particularly efficient thousandths-reading micrometers for checking work where a variety of dimensions are

involved.

Screw Thread Micrometers – are designed to measure the pitch diameter of screw threads to thousandths accuracy

by the use of a pointed spindle and double V-anvil which are available for varying diameters of work and each size

normally covers a range of the threads-per-centimeters.

Inside Micrometer –used for measuring the diameters of holes and other inside dimensions, consist of a permanent

contact micrometer head and a set of interchangeable rods in various increments which are seated snugly in the

opposite end of the head against a shoulder and locked securely.

Protractor – consists of a rectangular head graduated in degrees along a semi-circle, with a blade pivoted on the

center pin, any angle from 0 to 180 degrees can be set.

Combination Protractor and Depth Gage – is a combination of a movable graduated blade (depth gage) and a

graduated protractor head.

Universal Bevel Protractor – consist of a round body with a fixed blade, on which a graduated turret rotates.


5

Dial Indicator – composed of a graduated dial, spindle, pointers and a satisfactory means of supporting or clamping

it firmly, which is used to measuring inaccuracies in alignment eccentricity, and deviations on surfaces supposed to

be parallel.

Dial Test Indicator – commonly known as toolmaker’s indicator which are smaller than the smallest A.G.D. standard

indicator.

Planimeter – is a tool for checking the flatness of plane surfaces to tenths-of-thousandths of a centimeter and

consist of a diabase straight edge, and adjustable mounting for the straight edge, ,and a 0.00005 cm reading

indicator.

4. Non-Graduated Manual Measuring Tools

Calipers – follow a progression which originates with standard inside and outside calipers and are non-graduated

tools for measuring the distance between two points of contact on the work piece.

Standard Calipers – consist of two movable metal legs attached together by a spring joint at one end and with

formed contacts at the other, and so designed as to take inside readings, or readings from one point to another and

these are called inside calipers, outside calipers, and dividers, respectively.

Bevels – consists of two three-non-graduated slotted blades with one or two screws and knurled nuts connecting

them, by loosening the nuts, the blades can be set to varying angles.

Trammels – used in sizes beyond the range of dividers, consist of a long bar on which two arms or trammels slide.

Gage – is a device used to determine whether the part has been made to the tolerance required and does not

usually indicate a specific dimension.

Straight edges – are flat length of tools or stainless steel, ground to extremely fine tolerance, particularly along the

edges.

5. Special-Purpose Measuring Tools

Tap and Drill Gages – consist of a flat rectangle of steel with holes accurately drilled and identified according to their

size.

Wire Gages – are round steel plates with slots of ascending width along their edge.

Screw Pitch Gages – consist of a metal case containing many separate leaves.

Radius Gages – are individual leaves or a set of leaves in a case and are designed to check both convex and concave

radii.


6

Thickness / Feeler Gage – consists of a number of thin blades/leaves of different thickness and used in checking

clearances, backlash in gears and for gaging in narrow points or places.

6. Pressure and Vacuum Measurements

U-type Liquid-Column Gage – is made of glass or some other type of transparent tubing with an inner bore of 6 mm

or larger diameter and a wall thickness adequate to withstand the pressure for which the manometer was in design.

Well-Type Liquid-Column Gage – is similar to the U-type, however, one leg of the U-type is replace by a well.

Inclined Manometer or Draft Gage – is a well manometer whose vertical leg is placed in an almost horizontal

position so that a very slight difference of change in the pressure of the gas or air in the well causes a very large

change in the measured level of the liquid in the inclined tube.

Barometer – is an upright measuring tube which is vacuum sealed on the upright end and the open end and inserted

in a well filled with liquid mercury.

Limp-Diaphragm Gages – are used for measuring low pressure in boiler houses and on other implications where low

pressures must be accurately measured.

Bell-Type Gages – designed for measuring low pressures. This type of gage utilizes the large area of a liquid-sealed

bell chamber to provide the force necessary to actuate an indicating or recording mechanism and can be made

sensitive to the smallest change of pressure likely to be significant in an industrial application.

Piston Gages – suitable for pressure up to 350 kg/sq cm and higher but limited largely to hydraulic applications

where oil is the fluid under pressure.

Bourdon Tube Gage – is the most widely used in industrial pressure gage applied to both pressure and vacuum,

either separately or in a compound gage.

Helical Type of Pressure Gage – a variations of the simple Bourdon type of pressure gage wherein the element or

tube is wound in the form of a spiral having four or five turns.

Spiral Type of Element in Bourdon Type of Pressure Gage – the elements is of Bourdon type of tube wherein it is

wound in the form of a spiral having several turns rather than restricting the length of the tube to approximately 270

deg of arc.

Metallic-Diaphragm Pressure Gage – consists of a metal diaphragm built into diaphragm housing with one side of

the diaphragm exposed to the pressure to be measured and the other under atmospheric pressure.

Cam and Roller Arrangement – employs a can sector and a helicoids roller to which a pointer is attached.


7

Electromechanical Pressure Instruments – employ a mechanical means for detecting the pressure, and electrical

means for indicating or recording the detected pressure.

Electronic Pressure Measuring Instruments – depends on some physical change that can be detected and indicated

or recorded electronically.

Vacuum Gages – used primarily for measuring pressure below atmospheric pressure.

McLeod Gage – is a mercury gage for the measurement of absolute pressure.

Pirani Gage – is a hot wire vacuum gage. This gage employs a wheatstone bridge circuit to balance the resistance of

a tungsten filament or resistor sealed off in a high vacuum against that on a tungsten filament which can lose heat

by conduction to the gas whose pressure is being measured.

Knudsen Type Vacuum Gage – operates on the principle of heated gases rebounding from a heated surface and

bombarding a cooled movable surface spaced less than a mean free path length from the heated surface.

Phillips Vacuum Gage – are cold cathode ionization gages which provide direct measurement for pressure values

both above and below 1µm.

Alphatron Gage – uses a radium source sealed in a vacuum chamber where it is in equilibrium with its immediate

decay products.

7. Thermometry and Pyrometry

Indicating and Recording Thermometer – pressure actuated instrument that uses the energy available in the form of

increase pressure or volume of a substance to indicate and record the change in temperature that liberated this

energy.

Thermocouple Pyrometers – in which the voltage, generated at the junction of two dissimilar metal wires indicates

the degree of temperature, the voltage at the junction increasingly proportionally with the temperature.

Copper-Constantan – commonly used in the 185 to 300 C temperature range.

Iron-Constantan – used in reducing atmosphere where there is a lack of free oxygen and useful in the -18 to 760 C.

Chromel-Alumel – shall be used extensively in oxidizing atmospheres where there is an excess of free oxygen and

shall be used to measure temperature up to 1320 C, but are most satisfactory at temperatures up to 11509 C for

constant service.

Platinum-Platium-Rhodium – normally designated noble metal thermocouples, shall be used for higher temperature

range (700 to 1500 C) and are adversely affected by atmospheres containing reducing gases and shall be protected

by an impervious tube when used at temperatures above 540 C when such gases are present.


8

Resistance Thermometers – in which the resistance of a calibrated wire changes with the temperature, the

resistance change being proportional to the increase in temperature.

Thermistor – are electronic semiconductors whose electrical resistance varies with temperature and are useful

industrially for the automatic detection, measurement, and control of physical energy.

Liquid-filled Glass Thermometers – in which there is an expansion or contraction of a liquid corresponding to the

changes in temperature, the expansion of the liquid being proportional to the increase in temperature, the liquids

commonly used of which are mercury, alcohol, or pentane.

Bourdon Tube Thermostat – which operate by the expansion of a fluid (liquid or gas).

Radiation Pyrometers – in which there is a small body capable of absorbing radiation of all wave lengths, the

radiation absorbed being proportional to the temperature.

Optical Pyrometers – by which the temperatures is determined by matching the luminosity of the hot body of which

the temperature is to be determined with the luminosity of a calibrated source of light.

Pyrometer Cones – by which the temperature is determined by the bending over of a graded set of ceramic cones,

each having a definite heat resisting value.

Bimetallic Thermometers – depends on the differential expansion of two solids, the differential expansion being

proportional to the increase in temperature. Constructed of two thin strips of dissimilar metal which are bonded

together for their entire length.

Electronic Thermometers – the latest breakthrough in the measurements of temperature with very high accuracies,

fast speed of response and above average linearity.

8. Flow Metering

Inferential Type Flow Meters – obtains a measurement of the flow of a fluid or gas not by measuring the volume or

weight of the medium but by measuring some other phenomenon that is a function of the quantity of fluid passing

through the pipe.

Rotameter – consist of a tapered glass tube set vertically in the fluid or gaseous piping system with its large end on

top and a metering float which is free to move vertically in the tapered glass tube.

Anemometers – are instruments for measuring the flow of gas or air consisting of a set rotating vane placed at an

angle of about 45 degrees to the axis flow and free to rotate about an axis set in jeweled bearings

Hot Wire Anemometers – which consist of a small resistance wire inserted in the steam of gas whose velocity is to

be measured.


9

Thomas meter – which consist of wire grid inserted in the pipe line or duct and supplied with a current of sufficient

magnitude to heat the air passing through the pipe.

Electromagnetic Flowmeter – where an electromotive force is induced in the fluid by its motion through a magnetic

field provided by the electromagnet.

Piston-Type Volumetric Flow Meter – used to inject an exact amount of fluid into flow line or collecting vessel.

Nutating-Disc Pump – a positive displacement flowmeter wherein the piston is the only moving part on the

measuring chamber.

Rotary Sliding-Vane Flowmeter – a volumetric meter constructed similar to the standard vane type of vacuum pump,

wherein the design requires that the meter body be in the shape of a closed drum with shaft carrying a smaller

cylinder arranged to rotate inside the meter body.

Oscillating-Piston Flowmeter – consists of the hollow piston arranged to oscillate about the center abutment which

is encircled by a confining ring housed in a drum-shaped meter body.

Rotating-Bucket Flowmeter – a positive-displacement of a volumetric meter consisting of a meter with a drum type

of boy having the outlet and inlet ports side by side with a dividing baffle between them.

Screw Type of Flowmeter – consist of three meshed screws or rotors mounted vertically and rotating in a measuring

chamber.

Spiral-Vane Flowmeter – consists of metering chamber in which a rotor is mounted with a hollow shaft which admits

the liquid into a meter.

Bellows-Type Gas Flowmeter –design primarily and exclusively for gas-receiving bellows having metal slides and

tanned sheepskin flexible connections between the metal slides.

Water-Sealed Rotary Gas Meter – consists of a drum-shaped meter body slightly more than half full of water.

Roots Type of Volumetric Gas Meter – consist of a set of two rotors having a cross-sectional area in the

approximately shape of a figure eight.

Turbine-Type Current Flowmeters – used for measuring flows ranging from 0.003 to 15,000 gpm as standard liquid

flow meters, and 20 to 9000 cu. ft./min as gas flow meters.

9. Measurement of Weight

Platform Scale – used in the laboratory and consists of a compound leverage system.


10

Pendulum Scales – give automatic indication on over a wide range and are extensively used when speed is

important.

Electrical Scales – are combinations of mechanical elements and electrical measuring devices.

10. Rational Speed Measurements

Counter and Timer – a common type of revolution counter wherein the rubber of steel tip is applied directly to the

shaft center and friction is relied upon to drive the spindle.

Tachometer – gives a direct and continuous indications of speed and is therefore the most convenient for observing

speed variation or fluctuations and for general observations in which a high degree of accuracy is unnecessary.

Stroboscope – utilizes the phenomenon of persistence of vision when an object is viewed intermittently.

11. Environmental and Pollution Measurements

Humeter – instrument to measure the relative humidity of the atmospheric air which is important as comfort factor

and is measurable of how many airborne particulates are held in suspension where we can take them into our lungs

as we breathe.

Hygrometer / Psychrometer – instrument to measure also the relative humidity of the environment, which utilized

the physical or electrical change of certain materials as they absorbed moisture.

Hygrometers – depend on physical changes employ by human hair, animal membrane, or other materials that

lengthen when it absorb water.

Electrical Hygrometers – use transducers that convert humidity variations into electrical resistance changes.

- End -

O. PIPING - LECTURE

1

1. Definitions

The fundamental difference between pipe and tube is the dimension standard to which each is manufactured.

Pipe – is a tube with a round cross section conforming to the dimensional requirements for nominal pipe size as

tabulated in table for pipe schedules.

Tube – is a hollow product of round or any other cross section having a continuous periphery.

Black Pipe – steel pipe that has not been galvanized.

Bell and Spigot Joint – the commonly used joint in cast-iron pipe. Each piece is made with an enlarged diameter or

bell at one end into which the plain or spigot end of another piece is inserted when laying. The joint is then made

tight by cement, oakum, lead or rubber caulked into the bell around the spigot.

Bull Head Tee – a tee the branch of which is larger than the run.

Butt Weld Joint – a welded pipe joint made with the ends of the two pipes butting each other, the weld being

around the periphery.

Carbon Steel Pipe – steel pipe which owes its properties chiefly to the carbon which it contains.

Check Valve – a valve designed to allow a fluid to pass through in one direction only.

Compression Joint – a multi-piece joint with cup shaped threaded nuts which, when tightened compress tapered

sleeves so that they form joint on the periphery of the tubing they connect.

Cross-Over – a small fitting with a double offset, or shaped like the letter U with the ends turned out.

Expansion Loop – a large radius bend in a pipe line to absorb longitudinal expansion in the pipe line due to heat.

Galvanized Pipe – steel pipe coated with zinc to resist corrosion.

Gate Valve – a valve employing a gate, often wedge-shaped, allowing fluid to flow when the gate is lifted from the

seat. Such valves have less resistance to flow than globe valves.

Globe Valve – one with a somewhat globe shaped body with a manually raised or lowered disc which when closed

rests on a seat so as to prevent passage of a fluid.

Header – a large pipe or drum into which each of a group of boilers is connected.

Malleable Iron – cast-iron heat-treated to reduce its brittleness.

Manifold – a fitting with a number of branches in line connecting to a smaller pipes. Used largely as an

interchangeable term with header.

Medium Pressure – when applied to valves and fittings, implies they are suitable for a working pressure of from 862

to 1207 kPa (125 to 175 psi).

O. PIPING - LECTURE

2

Mill Length – also known as random length. Run-of-mill pipe is 4880 mm to 6000 mm in length. Some pipe are made

in double lengths of 9150 to 10,68=75 mm.

Relief Valve – one designed to open automatically to relieve excess pressure.

Run – a length of pipe made of more than one piece of pipe.

Saddle Flange – a flange curved to fit a boiler or tank and to be attached to a threaded pipe. The flange is riveted or

welded to the boiler or tank.

Socket Weld – a joint made by use of a socket weld fitting which has a prepared female end or socket for insertion of

the pipe to which it is welded.

Standard Pressure – formerly used to designate cast-iron, flanges, fittings, valves, etc., suitable for a maximum

working pressure of 862 kPa.

Street Elbow – an elbow with male thread on one end, and female thread on the other end.

Stress-Relieving – uniform heating of a structure or portion thereof to a sufficient temperature to relieve the major

portion of the residual stresses, followed by uniform cooling.

Wrought Iron – iron refined to a plastic state in a puddling furnace.

Wrought Pipe – this term refers to both wrought steel and wrought iron. Wrought in this sense means worked, as in

the process of forming furnace-welded pipe from skelp, or seamlell pipe from plates or billets.

2. Fluid Flow Velocities

Water - - - 1.5 to 3.0 m/s

High Pressure Saturated Steam - - 25 to 50 m/s

High Pressure Superheated Steam - - 50 to 77 m/s

Atmospheric Exhaust Steam - - 40 to 60 m/s

Low Pressure Exhaust Steam - - 100 to 120 m/s

O. PIPING - LECTURE

3

3. Identification Colors for Pipes

O. PIPING - LECTURE

4

4. Schedule Number

Schedule number – standard designation for pipes and is approximated by

S

pNumberSchedule

1000≈

where:

p = gauge pressure

S = working stress

5. Pipe Wall Thickness for Power Piping System

CYPS

pDtm +

+

=

2

where:

tm = minimum pipe wall thickness

p= maximum internal service pressure

t = nominal pipe wall thickness

D = outside diameter of pipe

S = allowable stress in materials

C = allowance for threading, mechanical strength or corrosion depending on the type of pipe.

Y = coefficient for type of steel and temperature.

Since all pipe furnished by the mill is subject to 12 ½% variation in wall thickness, the thickness tm should be

multiplied by 8/7 to obtain the nominal wall thickness t.

6. Pipe Wall Thickness for Industrial Gas and Air Piping System, for Refrigerant Piping System.

CPS

pDtm +

+

=

802 .

where:

tm = minimum pipe wall thickness

p= maximum internal service pressure

t = nominal pipe wall thickness

D = outside diameter of pipe

S = allowable stress in materials

C = allowance for threading, mechanical strength or corrosion.

7. Classification of piping systems based on the fluid carried.

a. Steam

b. Cold Water

c. Hot Water

8. Classification of piping systems based on the service conditions.

a. High-pressure superheated or saturated steam

b. High-pressure drip piping

c. Low-pressure steam piping

d. Boiler feedwater piping

e. Heater piping

O. PIPING - LECTURE

5

f. Blow-off piping

g. Condensate piping

h. Hot and cold water service piping

9. Commercial Pipe

9.1 Cast iron – is principally used for drainage or for resistance to corrosion and abrasion.

9.2 Wrought steel – most power plant piping, low-cost and strong.

9.3 Alloy steels – are steels which owe their special properties to alloying elements other than carbon.

9.4 Wrought iron – is a two-component metal consisting of iron permeated with 1% to 3% of finely divided and

uniformly distributed iron silicate.

9.5 Copper and Brass – the use of it is limited by its cost to piping in which flexibility, appearance, or resistance to

certain forms of corrosion are important.

10. Pipe Connections

a. Packed joints – such as leaded bell-and-spigot, or plain end coupling.

b. Screwed joints – such as couplings and unions.

c. Flanged Joints – with companion flanges either loose or screwed, shrunk, riveted, or welded to the pipe.

d. Welded joints – weld made by the fusion process using gas or metal arc welders.

11. Pipe Fittings

Fittings – consist of the pieces required to make turns, junctions, and reductions. The straight size fittings are the 45

deg and 90 deg elbows, the tees, crosses, Y’s, laterals, and reducers.

12. Common Valves

12.1 Globe valves (straight or angle)

a. Inside screw; outside screw

b. Screw bonnet top; bolted yolk top

12.2 Gate valves (straight or angle)

a. Rising stem; nonrising stem

b. Wedge valve (split and solid); parallel seat valve

12.3 Check valves (lift and swing types)

a. For vertical pipe

b. For horizontal pipe

13. Common Valves Materials

a. Bronze valves – noncorrosive, very malleable

b. Iron valves – iron body, bronze mounted (IBBM); or all iron

c. Cast steel – high strength carbon or alloy steel with special high-temperature duty seat trim

14. Special Valves

a. Safety Valves – are primarily the boiler safety valves which constitute the ultimate line of defense against the

occurrence of hazardous steam pressures in the boiler.

b. Relief Valves – is a form of safety valve, but usually intended for less severe service and of less importance from

the safety viewpoint.

c. Blow-off Valves – together with their connected lines, are to rid the mud drums of sediment accumulations, to

drain the boiler, to reduce concentration of boiler water, and to provide a means for rapidly lowering the boiler

water level in case the feedwater regulator becomes deranged or hand regulation has been careless.

O. PIPING - LECTURE

6

d. Control and Regulating Valves – are for water level, steam pressure, water flow, etc. Some makes are

thermostatically controlled, others mechanically, as by a float, others by pressure either steam, hydraulic, or

pneumatic.

e. Boiler Outlet Valves – are of the stop-check or automatic non-return type so as to prevent one of boilers in

parallel receiving backflow from the others should its pressure become substandard.

15. Steam Traps

Continuous float traps – are primarily a float-operated valve, quite simple in principle and operation.

Intermittent float traps – the bucket trap is a well-known example, this being seen in upright and inverted bucket

traps.

Upright bucket traps – floats on the incoming condensation and holds the discharge valve closed until the

accumulating water rises in the trap body far enough to spill into the bucket.

Inverted bucket traps – vents both the condensate and air through the main valve.

Thermostatic traps – a temperature-sensitive element is used to detect whether steam or condensate surrounds it.

Expansion, or orifice traps – have a flash chamber, or expansion chamber, between two restrictions in the flow line.

- End -

P. FIRE PROTECTION SYSTEMS - LECTURE

1

1. General

Fire protection engineering – involves designing devices, systems and processes to serve a particular function. In this

case the function is protecting people, property and business operations from the results of fire.

2. Commodity Classification

Class I – is defined as essentially non-combustible product on wood pallets, or in ordinary corrugated cartons with or

without single thickness dividers, or in ordinary paper wrapping, all on wood pallets.

Ex. Metal Products, Foods.

Class II – is defined as products in slatted wooded crates, solid wooden boxes, or equivalent combustible packaging

materials on wood pallets.

Ex. Incandescent lamps or fluorescent bulbs, beer or wine up to 20 percent alcohol

Class III – is defined as wood, paper, natural fiber cloth, plastic products on wood pallets, products may contain a

limited amount of plastics.

Ex. Wood dresserd with plastic drawer glides, handles, and trim.

Class IV – is defined as products containing an appreciable amount of plastics in paper board cartons on wood

pallets.

Ex. Small appliances, typewriters, and cameras with plastic parts.

3. Definitions

Available Height for Storage – the maximum height at which commodities, packaging or storage can be stored above

the floor and still maintain adequate clearance from structural members and the required clearance below

sprinklers.

Ordinary Combustibles – this term designates commodities, packages or storage aids which have heats of

combustion kilojoules per kilogram similar to wood, cloth or paper and which produce fires that may normally be

extinguished by the quenching and cooling effect of water.

Exposure – the exterior presence of combustibles which, if ignited, could cause damage to the storage building or its

contents.

Fire Wall – a wall designed to prevent the spread of fire having a fire resistance rating of not less than four hours and

having sufficient structural ability under fire conditions to allow collapse of construction on either side without

collapse of wall.

Horizontal Channel – any uninterrupted space in excess of 1524 m in length between horizontal layers of stored

commodities.


2

Non-combustibles – this term designates commodities, packaging or storage aids which will not ignite, burn or

liberate flammable gases when heated to a temperature of 745 C for five minutes.

Packaging – this term designates any commodity wrapping, cushioning or container.

Storage aids – this term designates commodity storage devices such as shelves, pallets, dunnage, decks, platforms,

trays, bins, separators and skids.

Warehouse – any building or area within a building used principally for the storage of commodities.

Extra Combustible – materials, which, either by themselves or in combination with their packaging, are highly

susceptible to ignition and will contribute to the intensity and rapid spread of fire.

Moderate Combustible – materials or their packaging, either of which will contribute fuel to fire.

Non-Combustibles – materials and their packaging which will neither ignite nor support combustion.

Approved – acceptable to the “Authority having jurisdiction”/

Authority Having Jurisdiction – is the organization, office or individual responsible for approving equipment, an

installation or procedure.

Class A Fire – fire involving ordinary combustible materials such as wood, cloth, paper, rubber and plastics.

Class B Fire – fire in flammable liquids and gases.

Class C Fire – fire involving energized electrical equipment.

Class D Fire – fire involving combustible metals, such as magnesium, sodium, potassium, titanium, and other similar

metals.

Dry Stand Pipe- a type of stand pipe system in which the pipes are not normally filled with water.

Fire Service – an organization or a component of the Philippine National Police Fire Department personnel in-charge

with the mission of fire prevention, fire protection.

Means of Egress – a continuous and unobstructed route of exit from any point in a building, structure or facility to a

safe public way.

Occupant Load – the maximum number of persons that may be allowed to occupy a particular building, structure, or

facility or portion thereof.


3

Shall – indicate a mandatory requirement.

Should – indicates a recommendation or that which is advised but not required.

Sprinkler system – is an integrated system of one or more water supplies for fire use, underground and overhead

piping designed in accordance with fire protection engineering standards.

4. Classification of Storage

Type I – is that in which combustible commodities or noncombustible commodities involving combustible packaging

or storage aids are stored over 4,550 mm but not more than 6,400 mm high in solid piles or over 3,650 mm but not

more than 6,400 mm high in piles that contain horizontal channels.

Type II – is that in which combustible commodities or noncombustible commodities involving combustible packaging

or storage aids are stored not over 4,500 mm high in sold piles or not over 3,650 mm high in piles that contain

horizontal channels.

Type III – is that in which the stored commodities packaging and storage aids are noncombustible or contain only a

small concentration of combustibles which are incapable of producing a fire that would cause appreciable damage

to the commodities stored or to noncombustible wall, floor or roof construction.

5. Classification of Sprinkler Systems

Wet Pipe System – a system employing automatic sprinklers attached to a piping system containing water and

connected to a water supply so that water discharges immediately from sprinkles opened by a fire. This is the type

of sprinkler system commonly used and adaptable to the climate in our country.

Deluge system – a system employing open sprinklers attached to a piping system connected to a water supply

through which is opened by the operation of a fire detection system installed in the same areas as sprinklers; when

this valve opens, water flows into the piping system and discharges from all sprinklers attached thereto.

6. Classification of Occupancies

Light Hazard Occupancies – occupancies where the quantity and/or combustibility of contents are low and fire with

relatively low rate of heat release are expected.

Ex. Churches, Clubs, Educational.

Ordinary Hazard Occupancies:

a. Ordinary Hazard Group 1 – occupancies where combustibility is low, quantity of combustible is moderate,

stockpiles of combustibles do not exceed 2,400 mm and fire with moderate rate of heat release are expected.

Ex. Automobile parking garages, Bakeries, Beverages manufacturing

b. Ordinary Hazard Group 2 – occupancies where quantity and combustibility of content is moderate. Stockpiles do

not exceed 3,700 mm and fire with moderate heat release is expected.

Ex. Machine shops, Metal working, Cold storage warehouses.


4

c. Ordinary Hazard Group 3 – occupancies where quantity and/or combustibility of contents is high, and fire of

high rate of release are expected.

Ex. Feed Mills, Pulp and Paper Mills, Paper Process Plants.

Extra Hazard Occupancies – occupancies where quantity and combustibility of contents is very high, and flammable

and combustible liquid, dust, lint or other materials are present introducing the probability of rapidly developing fire

with high rate of heat release.

a. Extra Hazard Group 1 – include occupancies with little or no flammable or combustible liquids.

Ex. Die Casting, Metal Extruding, Plywood and Particle Board Manufacturing.

b. Extra Hazard Group 2 – include occupancies with moderate to substantial amount of flammable or combustible

liquids or where shielding of combustible is extensive.

Ex. Asphalt Saturating, Flammable Liquids Spraying

7. Establishment to be protected with automatic water sprinkler system (Fire Code of the Philippines)

a. High Rise Buildinigs

b. Places of Assembly

c. Educational Building

d. General Storage

e. Institutional Occupancies or Residential Areas

f. Mercantile Occupancies

g. Business Occupancies

h. Industrial Occupancies

i. Pier and Water Surrounded Structure

j. Cellulose Nitrate Plastics (Pyroxilin)

k. High Piled Combustible Stock

l. Dip Tanks

8. Portable Fire Extinguishers

Portable Fire Extinguishers – are appliances to be used by the occupants of a building or area, primarily for

immediate used on small fires.

9. Basic Types of Fire

a. Class A Fires

b. Class B Fires

c. Class C Fires

d. Class D Fires

- End -

Q. MATERIAL HANDLING - LECTURE

1

1. Definitions

Boom – a timber or metal section or strut which is pivoted or hinged at the heel (lower end) at a fixed point on a

frame, mast, or vertical member.

Boom Type Extractor – a power operated excavating crane-type machine used for digging or moving materials.

Booming, Luffing or Topping – raising or lowering the head of a boom.

Brake (Electric) – an electric motor acting as a brake by regenerative, counter-torque, or dynamic means.

Brake (Electrically Operated) – a friction brake actuated or controlled by electrical means.

Bridge (of an Overhead, Gantry, or Storage Bridge Crane) – structural member or members supporting one or more

trolleys.

Buffer –a cushioning device at the end of trolley, bridge, or other moving part of a crane operating on rails to

minimize shock in the event of collision.

Bumper – a device which stops the moving part at the limit of travel of a trolley, bridges, or crane operating on rails,

and prevents further motion beyond that point.

Cab – an enclosure for housing the operator and the hoisting mechanism, power plant, and equipment controlling

crane.

Cage – an enclosure for housing the operator and equipment controlling a crane.

Crane – a machine for lifting or lowering a load and moving it horizontally, in which the hoisting mechanism is an

integral part of the machine.

Boom Type Mobile Crane – a self-propelled crane equipped with a boom and mounted on a chassis which is

supported on either rubber tires, endless belts or treads, or railway wheels running on railroad tracks.

Cantilever Gantry Crane – a crane in which the bridge girders or trusses are extended transversely beyond the crane

runway on one or both sides.

Crawler Crane – a boom type mobile crane mounted on endless tracks or tread belts.

Gantry Crane – a crane similar to an overhead traveling, except that the bridge for carrying the trolley or trolleys is

rigidly supported on two or more movable legs running on fixed rails or other runway.

Hammerhead Crane – a rotating counterbalanced cantilever equipped with one or more trolleys and supported by a

pivot or turntable on a traveling or fixed tower.

Jib Crane – a fixed crane consisting of a supported vertical member from which extends horizontal swinging arms

carrying a trolley hoist or other hoisting mechanism.

Locomotive Crane – a boom type mobile crane consisting of a self-propelled car operating on a railroad track.


2

Motor-Tractor Crane – see crawler crane.

Motor Truck Crane – a boom type mobile crane mounted on a motor truck frame or rubber-tire chassis.

Overhead Travelling or Bridge Crane – a crane on a pair of parallel elevated runways, adapted to lift and lower a load

and carry it horizontally parallel to, or at right angles to, the runways, or both.

Pillar Crane – a fixed crane consisting of a vertical member held at the base, with horizontal revolving arm carrying a

trolley.

Pillar Jib Crane – a fixed crane consisting of a vertical member held at the base, with horizontal revolving arm

carrying a trolley.

Pintle Crane – a crane similar to the hammerhead, but without a trolley, and which supports the load at the outer

end of the cantilever arm.

Portal Crane – a gantry crane without trolley motion, which has the boom attached to a revolving crane mounted on

a gantry, with the boom capable of being raised or lowered at its head (outer end).

Semi-Gantry or Single Leg Crane – a gantry with one of the bridge rigidly supported on one or more movable legs,

running on a fixed rail or runway, the other end of the bridge being supported by a truck running on an elevated rail

or runway.

Semi-Portal Crane – A portal crane mounted on a semi-gantry frame instead of a gantry frame.

Tower Crane – a portal crane, with or without an opening between the legs of its supporting structure, adapted to

hoist and swing load over high obstructions and mounted upon a fixed or mobile tower-like gantry.

Tractor Crane (Caterpillar Crane) – see crawler crane.

Wall Crane – a crane having jib with or without a trolley and supported from a side wall or line of columns of a

building so as to swing through an arc.

Crane Runway – the structure upon which a crane runs.

Derrick – a structure or building appurtenance for hoisting, but does not include a hoistway nor a car or platform

traveling thorough guides.

Hoist – a mechanical contrivance for raising or lowering a load by the application of a vertical pulling force, but does

not include a car or platform traveling through guides.

Base-Mounted Electric Hoist – a hoist similar to an overhead electric hoist, except that it has a base or feet and may

be mounted overhead, on a vertical plane, or in any position for which it is designed.

Clevis Suspension Hoist – a hoist whose upper suspension member is a clevis or a U-shaped structural member

designed to carry pulling loads.

Hook Suspension Hoist – a hoist whose upper suspension member is a hook.


3

Monorail Hoist – a trolley suspension hoist whose trolley is suspended from a single rail.

Overhead Electrical Hoist – a motor-driven hoist having one or more drums or sheaves for rope or chain, and

supported overhead.

Simple Drum Hoist – a hoist with one or more drums controlled by manually operated clutches, brakes, or ratched

and pawl on drum and control levers, which is operated by hand or power.

Double Drum Hoist – a simple drum hoist having two independent hoisting drums.

Single Drum Hoist – a simple drum hoist having only one hoisting drum.

Single Fixed Drum Hoist – a single drum hoist with the drum geared or fixed directly to the power unit instead of by

means of friction clutches.

Triple Drum Hoist – a simple drum hoist having three independent hoisting drums.

Trolley Suspension Hoist – a hoist whose upper suspension member is a trolley, for the purpose of running the hoist

below a suitable runway, it may be either floor or cage-operated.

Jib – a horizontal arm, for supporting a trolley or fall block, which does not change its inclination with the horizontal.

Jib – an extension added to the head of a boom for increasing the reach.

Radius (of a Crane or Derrick) – the horizontal distance from the center of rotation of a tower, hammerhead portal

or pillar crane, or derrick to the center of the hook or load.

Swinging or Slewing – the act of moving a boom through a horizontal arc.

Trolley – a truck or carriage on which the hoisting mechanism is mounted and which travels on an overhead beam or

track.

Truck (of an overhead, gantry, or locomotive crane) – the framework and wheels operating on the runway or rails

and supporting the bridge, trolley, or body of the crane.

2. Auxiliary Hoisting Equipment

2.1 Hoisting chains and ropes

2.2 Hooks, slings, and fittings

2.3 End attachment

2.4 Chain splices

2.5 Hoist for sling hooks, rings, and chain links

2.6 Sheave nip-point

- End -

R. AC AND DC MACHINERY - LECTURE

1

1. Transformers

Transformers – are devices used for transferring electric energy from one AC circuit to another with change in

frequency.

2. Types of Transformers

2.1 Step-up – receives energy at one voltage and delivers it at a higher voltage.

2.2 Step-down – receives energy at one voltage and delivers it at a lower voltage.

2.3 One-to-one – receives energy at one voltage and delivers it at the same voltage.

3. Industrial Uses of Transformers

3.1 Step up the voltage to high values for transmission purposes and thus effect a saving in the weight.

3.2 Step down the voltage from its transmission value to values suitable for industrial uses such as operating motors

and supplying lamps.

4. Transformer Principle

A transformer is based on the principle that energy maybe efficiently transferred by magnetic induction from one

set of coils to another set by a varying magnetic flux, provided both sets of coils are on the same magnetic circuit.

5. Synchronous Motors

5.1 DC generator – when supplied with electrical energy at its rated voltage, operates satisfactorily as a motor and

at the same electrical rating as when operating as a generator.

5.2 Synchronous generator – when supplied with electrical energy at its rated voltage and frequency, operates

satisfactorily as a motor and at the same electrical rating as when operating as a generator.

5.3 Synchronous motor – when a synchronous machine operates as a motor.

6. Types of Motors for Machine Shop Equipment and Forging Machinery

A – adjustable speed, shunt-wound, direct-current motor, wherever a number of speeds are essentials.

B – constant speed, shunt-wound, direct-current motor, when the required speeds are obtainable by a gear-box or

other adjustable speed transmission or when only one speed is required.

C – squirrel-cage induction motor, when direct-current is not available a gear-box or other adjustable speed

transmission must be used to obtain different speeds.

D – constant speed, compound-wound, direct-current motor, when speeds are obtainable by a gear-box or other

adjustable speed transmission or when only one speed is required.

E – wound secondary or squirrel-cage induction motors with approximately 10 percent slip, when direct current is

not available.

F – adjustable speed, compound-wound, direct-current motor.

- End -

industrial plant engineering reviewer - complete.pdf

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