Chapter 5: Steam Traps, Water Hammer, and Insulation

Question 1

The coefficient of thermal conductivity of an insulating material:
Select one:

a.
Does not change with temperature

b.
Is higher for glass fibre than steel

c.
Is lower when the material has a large number of microscopic air spaces

d.
Is decreased as the number of air spaces in the material decreases

e.
Is affected by atmospheric pressure

Answer 1

c.
Is lower when the material has a large number of microscopic air spaces

Question 2

Out of the steam traps listed below, which one uses the heat energy of the stream and condensate to operate?.
Select one:

a.
Impulse

b.
Bellows

c.
Ball float

d.
Inverted bucket

e.
Corrugated

Answer 2

a.
Impulse

Question 3

A2C05Q04 When the inlet and outlet to a steam trap are checked, it is noted that they are at the same temperature. This could mean that the trap line is blocked or that the trap is undersized. What other factors would indicate that the trap is undersized?
Select one:

a.
The trap would make a rattling noise

b.
The trap would only discharge condensate intermittently

c.
The trap would be silent

d.
The trap would have a continuous, smooth discharge

Answer 3

d.
The trap would have a continuous, smooth discharge

Question 4

A2C05Q09 Which type of insulation is formed into soft masses to be applied to irregular surfaces?
Select one:

a.
Insulating cement

b.
Calcium silicate

c.
Elastomeric

d.
Glass fibre

Answer 4

a.
Insulating cement

Question 5

A2C05Q10 Besides protection from mechanical damage, what else does insulation cladding do?
Select one:

a.
Allows insulation to be installed on irregular surfaces

b.
Provides rigidity to insulation installed on flexible lines

c.
Allows insulation to be installed in prefinished sections

d.
Reduces radiation heat losses

Answer 5

d.
Reduces radiation heat losses

Question 6

When metal cladding is used in chemical installations where there are caustic lines, the insulation is covered or wrapped with _____.
Select one:

A.
Stainless steel

B.
Canvas

C.
Linen

D.
Galvanized tin

E.
Aluminum

Answer 6

A.
Stainless steel

Question 7

Which of the following factors should be considered in steam trap selection?
1. Condensate capacity, under start-up
2. Condensate capacity, under normal operating conditions
3. Condensate temperature that the trap will have to handle
4. Steam header temperature
5. Pressure differential across the trap
6. The location of the trap
Select one:

a.
1, 3, 4, 5, 6

b.
1, 2, 3, 4, 5, 6

c.
1, 2, 3, 5, 6

d.
1, 2, 3, 4

e.
5, 6

Answer 7

b.
1, 2, 3, 4, 5, 6

Question 8

A2C05Q02 A thermostatic-type steam trap can handle large amounts of condensate but cannot handle what?
Select one:

a.
Superheated steam

b.
Large amounts of air

c.
Low-pressure steam

d.
Freezing temperatures

Answer 8

a.
Superheated steam

Question 9

A2C05Q03 A steam trap installed on a steam main must be able to handle the largest amount of condensate created in the line. When does this large amount of condensate typically occur?
Select one:

a.
During steady states

b.
During shutdown

c.
During load changes

d.
During start-up

Answer 9

d.
During start-up

Question 10

Which of the following traps is a thermodynamic type?
Select one:

a.
Impulse

b.
Bellows

c.
Ball float

d.
Inverted bucket

e.
F and T trap

Answer 10

a.
Impulse

Question 11

Centrifugal type steam separators have _____ sets of baffles:
Select one:

a.
5

b.
1

c.
3

d.
4

e.
2

Answer 11

e.
2

Question 12

The phenomenon of water hammer in pipe lines is caused by which of the following?
1. Rapid opening of valves
2. Rapid condensation of a pocket of steam
3. Rapid closing of valves
4. Sudden stopping of a motor-driven centrifugal pump
5. Rapid opening of the check valve
Select one:

a.
1, 2, 3, 4

b.
2, 3, 4

c.
3, 4, 5

d.
1, 2, 3

e.
2, 4, 5

Answer 12

a.
1, 2, 3, 4

Question 13

Steam traps may be classified into the following types according to their principles of operation:
Select one:

a.
Mechanical, float, temperature

b.
Mechanical, thermostatic, thermodynamic

c.
Thermodynamic, thermostatic, float & thermostatic

d.
Impulse, bellows, bucket

e.
Thermodynamic, steam pressure, mechanical

Answer 13

b.
Mechanical, thermostatic, thermodynamic

Question 14

If several traps drain into a common return header, a _____ valve should be installed between the trap and the return header.
Select one:

a.
Check

b.
Globe

c.
Gate

d.
Control

e.
Butterfly

Answer 14

a.
Check

Question 15

A material suitable for use as insulation should have which of the following characteristics?
Select one:

a.
Transmits heat poorly

b.
Transmits heat readily

c.
Has no k value

d.
Has a small number of microscopic air pockets

e.
Eliminates heat loss

Answer 15

a.
Transmits heat poorly

Question 16

A2C05Q01 Which type of steam separator is the simplest in design and has the lowest efficiency?
Select one:

a.
Mechanical coalescing separator

b.
Coalescing separator

c.
Baffle-type separator

d.
Centrifugal separator

Answer 16

c.
Baffle-type separator

Question 17

Which of these tasks should be done during a yearly trap inspection?
1. The trap body and operating parts should be examined for corrosion, erosion, mechanical wear, etc.
2. All internal parts should be cleaned and worn valves, seats, levers etc. should be replaced, as should cracked buckets, floats, or bellows.
3. Check trap housing temperature.
4. All gasket seating surfaces should be thoroughly cleaned and new gaskets used on reassembly.
Select one:

a.
1, 2, 3, 4

b.
1, 2

c.
1, 2, 4

d.
1, 2, 3

e.
2, 3, 4

Answer 17

c.
1, 2, 4

Question 18

Where are strainers installed in steam lines?
Select one:

a.
Downstream of separators

b.
To reduce steam temperature

c.
To remove moisture

d.
To prevent water hammer

e.
Before steam traps

Answer 18

e.
Before steam traps

Question 19

What type of insulation will most likely be used for high-pressure steam piping?
Select one:

a.
Fibreglass

b.
Cloth

c.
Calcium silicate

d.
Refractory fibre

e.
Cellulose

Answer 19

c.
Calcium silicate

Question 20

A2C05Q07 When warming up a steam header, when may the main header isolation valve be cracked open?
Select one:

a.
After the bypass is fully opened and there is no pressure rise in the steam header

b.
At the same time as the bypass is opened

c.
After steam flow is established

d.
Once all traps are proven to be working properly

Answer 20

a.
After the bypass is fully opened and there is no pressure rise in the steam header

Question 21

Find the warm-up load in kg/h in warming up 50 m of 203.2 mm, schedule 40 steel pipe to a working pressure of 1737 kPa in a warm-up time of 20 minutes. Initial temperature of the pipe is 20°C. The mass/unit length of the pipe is 42.2 kg/m. Assume the specific heat of the steel is 0.494 kJ/kg°C.
Select one:

a.
500.7 kg/h

b.
10.29 kg/h

c.
58 kg/h

d.
2142 kg/h

e.
301.4 kg/h

Answer 21

e.
301.4 kg/h

Question 22

The primary purposes of insulation include which of the following?
1. Retaining heat in hot lines
2. Preventing corrosion of metal surfaces
3. Preventing high temperature in power plant buildings
4. Preventing injury to personnel
Select one:

a.
2, 3, 4

b.
1, 2, 3

c.
1, 3, 4

d.
1, 2, 4

e.
1, 2, 3, 4

Answer 22

c.
1, 3, 4

Question 23

A2C05Q05 Besides the rapid closing of a valve, what else might cause flow-induced water hammer?
Select one:

a.
The rapid opening of a valve

b.
A high pressure differential across a steam trap

c.
The gradual blockage of a steam trap

d.
A centrifugal pump suddenly tripping out

Answer 23

d.
A centrifugal pump suddenly tripping out

Question 24

A2C05Q06 What is the best way to avoid water hammer in a condensate return line?
Select one:

a.
Install the steam traps so the condensate discharges into a gravity return line.

b.
Ensure that the steam traps are fitted with automatic drains.

c.
Ensure proper venting arrangements are installed at regular intervals along the return line.

d.
Install steam traps in tandem, with minimal piping lengths between them.

Answer 24

a.
Install the steam traps so the condensate discharges into a gravity return line.

Question 25

Water hammer may occur in which of the following lines?
1. Steam
2. Water
3. Air
4. Oil
Select one:

a.
1, 2, 3

b.
2, 3, 4

c.
1, 3, 4

d.
1, 2, 4

e.
1, 2

Answer 25

d.
1, 2, 4

Question 26

In a thermostatic trap, the bellows are usually filled with:
Select one:

a.
Mercury

b.
Water

c.
Alcohol

d.
Carbon dioxide

e.
Helium

Answer 26

c.
Alcohol

Question 27

What is the most positive method to test a trap to ensure it is working?
Select one:

a.
Touch the body of the trap

b.
Observe the discharge by means of a test valve

c.
Check the temperatures of the inlet and outlet

d.
Remove the trap for bench testing

e.
Replace the trap with a new one

Answer 27

b.
Observe the discharge by means of a test valve

Question 28

A2C05Q08 Which insulation is used at temperatures above 815°C?
Select one:

a.
Cryogenic insulation

b.
Refractory insulation

c.
High-temperature insulation

d.
Thermal insulation

Answer 28

b.
Refractory insulation

Question 29

Which of the following traps is a thermodynamic type?
Select one:

a.
Impulse

b.
Bellows

c.
Ball float

d.
Inverted bucket

e.
F and T trap

Answer 29

a.
Impulse

Question 30

Glass fibre may be used for pipe insulation up to a temperature of:
Select one:

a.
454°C

b.
595°C

c.
150°C

d.
185°C

e.
212°C

Answer 30

a.
454°C