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Power Engineering 5th Class Book 1 > Book 1: 2-09 - Boiler Combustion Controls > Flashcards

Book 1: 2-09 - Boiler Combustion Controls Flashcards

1
Q

The time taken for the automatic pilot valve to close in the event of a loss of flame detection is about _____ seconds
Select one:

A. 20

B. 15

C. 10

D. 4

E. 2

A

C. 10

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2
Q

In an oil fired boiler the fuel enters the furnace in a _____ state mixes with combustion air and is ignited.
Select one:

A. Mixed

B. Gaseous

C. Liquid

D. Solid

E. Vapourized

A

E. Vapourized

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3
Q

If the pilot flame fails, no power is generated by the thermocouple preventing the _____ from supplying fuel to the burner on boiler startup.
Select one:

A. Operating control

B. Pilot fuel control valve

C. Air supply valve

D. Main fuel control valve

E. Main relay valve

A

D. Main fuel control valve

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4
Q

Each automatically fired hot water boiler shall have a high limit temperature control that will shut off the fuel supply to the boiler to prevent the water from exceeding the maximum allowable temperature of:
Select one:

A. 150°C (302°F)

B. 75°C (167°F)

C. 100°C (212°F)

D. 200°C (392°F)

E. 120°C (248°F)

A

E. 120°C (248°F)

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5
Q

In a gas fired boiler the fuel enters the furnace in a _____ state mixes with combustion air and is ignited.
Select one:

A. Liquid

B. Mixed

C. Gaseous

D. Vapourized

E. Solid

A

C. Gaseous

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6
Q

The infrared scanner is mounted on the end of a sighting tube in such a way that its temperature will not exceed:
Select one:

A. 50°C (98°F)

B. 75°C (167°F)

C. 100°C (212°F)

D. 150°C (302°F)

E. 120°C (248°F)

A

A. 50°C (98°F)

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7
Q

A flame rod uses the principle that a flame is capable of:
Select one:

A. Conducting electricity

B. Holding the solenoid open

C. Supplying fuel to the burner

D. Heating the rod

E. Holding the solenoid closed

A

A. Conducting electricity

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8
Q

The most commonly used flame detection devices are:
1. Ultraviolet detectors
2. Thermocouples
3. Flame rods
4. Infrared detectors
5. Photoelectric cells
Select one:

A. 1, 2, 4

B. 1, 2, 3

C. 3, 4, 5

D. 2, 3, 4

E. 2, 3, 5

A

E. 2, 3, 5

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9
Q

This [Ultraviolet?] scanner is mounted as close to the flame as physically possible without subjecting it to a temperature over:
Select one:

A. 100°C (212°F)

B. 50°C (98°F)

C. 120°C (248°F)

D. 75°C (167°F)

E. 150°C (302°F)

A

A. 100°C (212°F)

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10
Q

A photoelectric cell reacts to the _____ emitted by the flame.
1. Ultraviolet rays
2. Thermocouples
3. Flame rods
4. Infrared rays
Select one:

A. 1, 3

B. 1, 2

C. 1, 4

D. 2, 3

E. 2, 4

A

C. 1, 4

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11
Q

The infrared scanner contains a _____ cell which reacts to infrared rays.
Select one:

A. Lead sulphide

B. Lead sulphate

C. Lithium bromide

D. Sodium chloride

E. Sodium sulphide

A

A. Lead sulphide

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12
Q

The voltage supply generated by the thermocouple is usually not more than:
Select one:

A. 50 millivolts

B. 15 millivolts

C. 100 millivolts

D. 0 millivolts

E. 30 millivolts

A

E. 30 millivolts

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13
Q

A thermocouple consists of two dissimilar wires welded together at one end to form a:
Select one:

A. Reference junction

B. Metering junction

C. Electric circuit

D. Cold junction

E. Hot junction

A

E. Hot junction

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14
Q

If for any reason, the burner should go out during normal operation, or the fuel should fail to ignite during startup:
Select one:

A. Increase the fuel flow

B. The air to the burner must be shut off immediately

C. Increase the combustion air flow

D. No action is required

E. The fuel to the burner must be shut off immediately

A

E. The fuel to the burner must be shut off immediately

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15
Q

The rectifying photocell, shown in Fig. 10, is also known as a _____ cell.
Select one:

A. IR

B. Rectifying

C. UV

D. Photoelectric

E. Cad

A

E. Cad

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16
Q

With the photoelectric flame scanner upon loss of flame it should take no longer than _____ seconds for the gas valve to close.
Select one:

A. 15

B. 4

C. 10

D. 20

E. 2

A

B. 4

17
Q

The flame rod method of sensing is often referred to as:
Select one:

A. The ionized particle principle

B. Infrared detection

C. Photoelectric scanning

D. Flame rectification

E. Ultraviolet detection

A

D. Flame rectification

18
Q

Unburned fuel collecting in the furnace can mix with the combustion air and may ignite, causing a
Select one:

A. Water tube explosion

B. Boiler drum failure

C. Spike in steam production

D. Serious explosion

E. Fire tube failure

A

D. Serious explosion

19
Q

When the hot junction of a thermocouple is exposed to heat its temperature is higher than that of the cold junction and a small _____ is generated.
Select one:

A. Wattage

B. Resistance

C. Conductance

D. Amperage

E. Voltage

A

E. Voltage

20
Q

This scanner is mounted as close to the flame as physically possible without subjecting it to a temperature over:
Select one:

A. 150°C (302°F)

B. 75°C (167°F)

C. 120°C (248°F)

D. 100°C (212°F)

E. 50°C (98°F)

A

D. 100°C (212°F)

21
Q

The infrared scanner is mounted on the end of a sighting tube in such a way that it’s temperature will not exceed:

A. 50°C (98°F)
B. 100°C (212°F)
C. 120°C (248°F)
D. 75°C (167°F)
E. 150°C (302°F)

A

A. 50°C (98°F)

22
Q

The most commonly used flame detection devices are:
1. Ultraviolet detectors
2. Thermocouples
3. Flame rods
4. Infrared detectors
5. Photoelectric cells

Select one:

A. 3,4,5
B. 2,3,4
C. 2,3,5
D. 1,2,3
E. 1,2,4

A

C. 2,3,5

23
Q

If the pilot flame fails, no power is generated by the thermocouple preventing the _____ from supplying fuel to the burner on boiler startup.

Select one:
A. Main fuel control valve
B. Main relay valve
C. Operating control
D. Air supply valve
E. Pilot fuel control valve

A

A. Main fuel control valve

24
Q

With the photoelectric flame scanner upon loss of flame it should take no longer than _____ seconds for the gas valve to close.

Select one:

A. 2
B. 20
C.10
D. 4
E. 15

A

D. 4

25
Q

The voltage supply generated by the thermocouple is usually not more than:

Select one:

A. 0 millivolts
B. 15 millivolts
C. 100 millivolts
D. 50 millivolts
E. 30 millivolts

A

E. 30 millivolts

26
Q

The rectifying photocell, shown in Fig. 10, is also known as a _____ cell.

Select one:

A. IR
B. Cad
C. UV
D. Photoelectric
E. Rectifying

A

B. Cad

27
Q

The time take for the automatic pilot valve to close in the event of a flame detection is about _____ seconds

Select one:

A. 15
B. 4
C. 10
D. 20
E. 2

A

C. 10

28
Q

A photoelectric cell reacts to the _____ emitted by the flame.
1. Ultraviolet rays
2. Thermocouples
3. Flame rods
4. Infrared rays

Select one:

A. 1,3
B. 1,4
C. 1,2
D. 2,4
E. 2,3

A

B. 1,4

29
Q

If for any reason, the burner should go out during normal operation, or the fuel should fail to ignite during startup:

Select one:

A. Increase the fuel flow
B. No action is required
C. The air to the burner must be shut off immediately
D. The fuel to the burner must be shut off immediately
E. Increase the combustion air flow

A

D. The fuel to the burner must be shut off immediately

30
Q

When the hot junction of a thermocouple is exposed to heat it’s temperature is higher than that of the cold junction and a small ______ is generated.

Select one:

A. Conductance
B. Resistance
C. Wattage
D. Amperage
E. Voltage

A

E. Voltage

Power Engineering 5th Class Book 1 (25 decks)

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