4Th Class Power Engineering Chapter 59

Front 1

The ASAP Code states that "each boiler shall have at least one pressure relief valve and if it has more than _____m2 of bare tube water-heating surface, or if an electric boiler has a power input more than _______ Kw, it shall have ___ or more pressure relief valves.

Back 1

47 m2, 1,100 Kw, 2 or more

Front 2

Industry practice is that superheater and reheater safety valves must ______ ______ and _____ ______ drum safety valves. So that?

Back 2

Open before and close after

The superheater or reheater don't over heat due to a lack of cooling steam.

Front 3

The safety valve can't be manually opened unless the operating pressure of the boiler is at _____%

Back 3

75%

Front 4

If the safety valve is opened when there is no pressure what could happen?

Back 4

Scale or debris from the valve discharge line could fall into the valve preventing it from closing.

Front 5

ASME sections _____, ______ and _______ reference pressure relief valves.

Back 5

I, IV, VII

Front 6

The difference between the pressure at which the valve opens and closes is called the _____________.

Back 6

Blow down

Front 7

What is the opening pressure of a safety valve referred to as?

Back 7

Popping pressure

Front 8

Why would a safety valve have an exposed spring?

Back 8

To prevent the high temperature of the super heated steam from destroying the mechanical properties of the spring

Front 9

Torsion bar safety valves are designed for use on boilers operating at pressures of _________ kPa and higher

Back 9

8000 kPa

Front 10

If a long vertical discharge pipe is required, then it may be necessary to install a ______ _______ near the safety valve so that the expansion of the pipe won't put stress on the safety valve

Back 10

Flexible joint

Front 11

The ASME code recommends a try lever test be conducted how often?

Back 11

Once a month

Front 12

Pop tests should be conducted how often?

Back 12

At least once a year

Front 13

The regulations governing boiler safety valves are covered in detail in ASME Section _____.

Back 13

Section 1

Front 14

The temperature relief valve on a domestic hwt is designed to operate when temperatures reach approximately ______°C

Back 14

99°C

Front 15

Temperature relief valves can open on a rise in temperature by the expansion of a wax-filled rod or by the:

1) Melting of the alloy in a fusible plug

2) Action of a Bourdon tube

3) Action of a bi-metal strip

4) Melting of a fusible link

5) Action of a bellows

Back 15

1) Melting of the alloy in a fusible plug

Front 16

Safety valves "pop" open because the force of the steam:

1) Acts upon a blowdown ring

2) Decreases the force created by the spring

3) Acts upon a huddling chamber

4) Increases due to the discharge ports

5) Is suddenly increased due to a larger area

Back 16

5) Is suddenly increased due to a larger area

Front 17

LP boiler safety valves can be repaired:

1) By a licensed boiler operator

2) Only when authorized by the inspector

3) By anyone qualified to do so

4) By a qualified boiler operator after permission from the inspector

5) By only the manufacturer

Back 17

5) By only the manufacturer

Front 18

Popping pressure of a steam heating boiler safety valve may be adjusted:

1) Any amount

2) No more than the allowed blowdown

3) By anyone

4) Up to 7.5%

5) Up to 5%

Back 18

5) Up to 5%

Front 19

If you found the safety valve on your heating boiler stuck in the closed position while the boiler was in operation, the best thing to do is:

1) Shut down the boiler and repair or replace the safety valve

2) Report it to the shift team leader

3) Tap it gently with a bronze hammer to free it

4) Put the boiler on hand control and notify the inspector

5) Reduce the boiler pressure and continue operating

Back 19

1) Shut down the boiler and repair or replace the safety valve

Front 20

If the safety valve on a steam heating boiler opens, what is the pressure above the maximum allowable working pressure that the boiler is allowed to rise?

1) 35 kPa

2) 39 kPa

3) 50 kPa

4) 25 kPa

5) 27 kPa

Back 20

1) 35 kPa

Front 21

For a steam heating boiler, the safety valve shall be such that, with the fuel burning equipment installed and operated at maximum capacity, the pressure cannot rise more than _____ kPa above the maximum allowable working pressure when all steam outlets are closed.

1) 101

2) 100

3) 34

4) 103

5) 55

Back 21

3) 34

Front 22

If a safety valve fails to open at its popping pressure, you should:

1) Raise the pressure

2) Try the lifting lever

3) Tap it gently

4) Shut the boiler down

5) Reface the valve

Back 22

2) Try the lifting lever

Front 23

Cast iron fittings used for water columns and valves of a steam boiler can be deemed to have upper limitations of:

1) 1 100 kPa and 173ºC

2) 1 720 kPa and 232ºC

3) 3 000 kPa and 150ºC

4) 17 200 kPa and 1 100ºC

5) 8 000 kPa and 670ºC

Back 23

2) 1 720 kPa and 232ºC

Front 24

The popping pressure of a safety valve:

1) Can only be increased by 5%

2) Cannot be changed

3) Can only be decreased by 5%

4) Can be increased or decreased by up to 5%

5) Can be changed any amount

Back 24

4) Can be increased or decreased by up to 5%

Front 25

An operator should check that a boiler safety valve will open at its set pressure by:

1) Connecting the boiler to an air compressor during shutdown and raising the pressure in the boiler until the set pressure is reached

2) Sending for the inspector to bring his/her test gauge

3) Putting a piece of pipe over the lifting lever and lifting the valve off its seat when the seat pressure is reached

4) Increasing the boiler pressure until the valve opens and noting the pressure on the pressure gauge when the valve opened

5) Listening to the alarms of the set pressures

Back 25

4) Increasing the boiler pressure until the valve opens and noting the pressure on the pressure gauge when the valve opened

Front 26

If, during the testing of a safety valve, the valve does not open, you would first:

1) Try to open the valve with the lifting lever

2) Take the boiler out of service

3) Force it open by striking it with a hammer

4) Continue to increase the steam pressure

5) Stop the boiler and notify the Boiler's Branch

Back 26

1) Try to open the valve with the lifting lever

Front 27

When performing a safety valve pop test, one of the first things to do is:

1) Notify the chief engineer

2) Check the popping pressure

3) Check the blow down of the safety valve

4) Verify the accuracy of the applicable steam pressure gauge

5) Notify the boiler inspector

Back 27

4) Verify the accuracy of the applicable steam pressure gauge

Front 28

According to the current code, the valve seat diameter of the safety valve on a steam heating boiler must not be smaller than:

1) 63 mm (2 ½ in)

2) 13 mm (½ in)

3) 51 mm (2 in)

4) 38 mm (1 ½ in)

5) 25 mm (1 in)

Back 28

2) 13 mm (½ in)

Front 29

According to the current code, no safety valve on a steam heating boiler shall be smaller than:

1) 51 mm (2 in)

2) 15 mm (½ in)

3) 25 mm (1 in)

4) 7.5 mm (¼ in)

5) 100 mm (4 in)

Back 29

2) 15 mm (½ in)

Front 30

On steam heating boilers, the safety valve test lever must not be used unless:

1) Pressure is up to at least 34 kPa

2) The boiler inspector requests it

3) The boiler is at maximum pressure

4) There is no load on the boiler

5) The boiler is in operation

Back 30

1) Pressure is up to at least 34 kPa

Front 31

According to the current code, no safety valve on a steam heating boiler shall be larger than:

1) 50.8 mm (2 in)

2) 25.4 mm (1 in)

3) 63.5 mm (2 ½ in)

4) 38.1 mm (1 ½ in)

5) 115 mm (4 ½ in)

Back 31

5) 115 mm (4 ½ in)

Front 32

The steam heating boiler safety relief valve capacity for each boiler with a single safety relief valve shall be such that the pressure cannot rise more than _____ above the maximum allowable working pressure.

1) 6%

2) 20%

3) 10%

4) 15%

5) 5%

Back 32

3) 10%

Front 33

According to the current the minimum blowdown for a steam heating boiler safety valve is:

1) 5% of the set pressure

2) 30 kPa

3) 96% of the set pressure

4) 101.3 kPa

5) 14 kPa

Back 33

5) 14 kPa

Front 34

To raise only the closing pressure of the valve, one would:

1) Increase the tension on the spring

2) Decrease the spring tension

3) Screw the blowdown ring upwards

4) Screw the blowdown ring downwards

5) Decrease the seat diameter

Back 34

4) Screw the blowdown ring downwards

Front 35

The safety valves on a boiler meet code requirements and are set to a popping pressure of 1 380 kPa. What would be the maximum permissible pressure rise in the boiler if the boiler is fired at full capacity with the main steam stop valve closed?

1) 25 kPa

2) 82.8 kPa

3) 72.4 kPa

4) 47 kPa

5) 37.5 kPa

Back 35

2) 82.8 kPa

Front 36

A safety relief valve is like a safety valve except it:

1) Is prone to leakage

2) Must have greater blow down

3) Must discharge directly to the atmosphere

4) May have an isolation valve placed between it and the pressure vessel

5) Does not have a blowdown ring or bottom guides

Back 36

5) Does not have a blowdown ring or bottom guides