4B Power Engineering: Unit 3 - Boiler Safety Devices
Questions With Complete Solutions
a
On fully automatic boilers, the programming controller initiates
the ignition sequence when the _________ are closed:
Select one:
a. on-off and operating control switches
b. draft fan control switches
c. combustion air flow switches
d. fuel oil switches Correct Answers a
A _________ situation would stop the steam flow through the
superheater.
a. underpressure
b. overpressure
c. pressure drop
d. temperature drop Correct Answers b
A blowdown ring is used on a safety valve to:
Select one:
a. Adjust the differential between opening and closing pressures
b. Increase the blowdown frequency of the safety valve
c. Prevent the safety valve from popping while blowing down
the boiler
d. Adjust the operating pressure of the valve Correct Answers a
A blowdown ring on a safety valve is used to:Select one:
a. Increase the life of the cone shaped lip
b. Adjust the blowdown differential
c. Increase the effectiveness of the safety valve
,d. Set the opening pressure
e. Adjust the operating pressure of the valve Correct Answers b
A boiler feedwater isolation valve:
Select one:
a. May be a globe valve, provided water enters below the disc
b. Should be located close to the feedwater pump
c. Must be a globe valve
d. Is used to isolate the deaerator Correct Answers a
A boiler with a single safety valve has a maximum allowable
working pressure of 1000 kPa. What is the maximum boiler
pressure permissible when the safety valve is blowing?
Select one:
a. 1100 kPa
b. 1030 kPa
c. 1000 kPa
d. 1060 kPa Correct Answers d
A burner cannot begin a start-up sequence when the main test
firing valve is:
a. open
b. closed
c. upright
d. shut Correct Answers a
A digital input computer is protected from harmful voltages by
means of:
a) Fuses
b) Isolating circuits limits
c) Circuit breakers built
,d) Stand-alone devices Correct Answers b
A feedwater pipe, where connected to a power boiler, must
have:
a. A quick and slow opening stop valve
b. A stop valve only
c. A check valve between the stop valve and the boiler
d. A check valve, with a stop valve between the check valve and
the boiler Correct Answers d
A feedwater pipe, where connected to a power boiler, must
have:
Select one:
a. A quick and slow opening stop valve
b. A stop valve only
c. A check valve between the stop valve and the boiler
d. A check valve, with a stop valve between the check valve and
the boiler Correct Answers d
A flame control switch:Choose one answer.
a. Varies electrical current to a modutrol motor
b. Will start and stop a boiler
c. Cannot have its settings adjusted
d. Will not result in simultaneous adjustment of air and fuel
e. Eliminates the need for a high limit control Correct Answers
a
A flame failure device is unresponsive to:
Select one:
a. Fuel flow
b. Visible light
, c. Infra-red light
d. Ultraviolet light Correct Answers a
A flame rod:
Select one:
a. Develops a high resistance in the presence of a flame.
b. Forms an electric circuit with the rod, flame and burner
c. Is used only for oil fired burners
d. Is used in combination with a photocell Correct Answers b
A float operated low water fuel cutoff has its switch separated
from boiler pressure by:
Select one:
a. Packing
b. A seal cage
c. A bellows
d. A float cage Correct Answers c
A fuel strainer in a gas fuel train is fitted after the: Correct
Answers main manual shut-off valve
A gauge glass shows the level of a clear, colourless liquid as
very dark, is the ______________ gauge glass.
Select one:
a. Flat
b. Tubular
c. Reflex
d. Bi-colour Correct Answers c
Questions With Complete Solutions
a
On fully automatic boilers, the programming controller initiates
the ignition sequence when the _________ are closed:
Select one:
a. on-off and operating control switches
b. draft fan control switches
c. combustion air flow switches
d. fuel oil switches Correct Answers a
A _________ situation would stop the steam flow through the
superheater.
a. underpressure
b. overpressure
c. pressure drop
d. temperature drop Correct Answers b
A blowdown ring is used on a safety valve to:
Select one:
a. Adjust the differential between opening and closing pressures
b. Increase the blowdown frequency of the safety valve
c. Prevent the safety valve from popping while blowing down
the boiler
d. Adjust the operating pressure of the valve Correct Answers a
A blowdown ring on a safety valve is used to:Select one:
a. Increase the life of the cone shaped lip
b. Adjust the blowdown differential
c. Increase the effectiveness of the safety valve
,d. Set the opening pressure
e. Adjust the operating pressure of the valve Correct Answers b
A boiler feedwater isolation valve:
Select one:
a. May be a globe valve, provided water enters below the disc
b. Should be located close to the feedwater pump
c. Must be a globe valve
d. Is used to isolate the deaerator Correct Answers a
A boiler with a single safety valve has a maximum allowable
working pressure of 1000 kPa. What is the maximum boiler
pressure permissible when the safety valve is blowing?
Select one:
a. 1100 kPa
b. 1030 kPa
c. 1000 kPa
d. 1060 kPa Correct Answers d
A burner cannot begin a start-up sequence when the main test
firing valve is:
a. open
b. closed
c. upright
d. shut Correct Answers a
A digital input computer is protected from harmful voltages by
means of:
a) Fuses
b) Isolating circuits limits
c) Circuit breakers built
,d) Stand-alone devices Correct Answers b
A feedwater pipe, where connected to a power boiler, must
have:
a. A quick and slow opening stop valve
b. A stop valve only
c. A check valve between the stop valve and the boiler
d. A check valve, with a stop valve between the check valve and
the boiler Correct Answers d
A feedwater pipe, where connected to a power boiler, must
have:
Select one:
a. A quick and slow opening stop valve
b. A stop valve only
c. A check valve between the stop valve and the boiler
d. A check valve, with a stop valve between the check valve and
the boiler Correct Answers d
A flame control switch:Choose one answer.
a. Varies electrical current to a modutrol motor
b. Will start and stop a boiler
c. Cannot have its settings adjusted
d. Will not result in simultaneous adjustment of air and fuel
e. Eliminates the need for a high limit control Correct Answers
a
A flame failure device is unresponsive to:
Select one:
a. Fuel flow
b. Visible light
, c. Infra-red light
d. Ultraviolet light Correct Answers a
A flame rod:
Select one:
a. Develops a high resistance in the presence of a flame.
b. Forms an electric circuit with the rod, flame and burner
c. Is used only for oil fired burners
d. Is used in combination with a photocell Correct Answers b
A float operated low water fuel cutoff has its switch separated
from boiler pressure by:
Select one:
a. Packing
b. A seal cage
c. A bellows
d. A float cage Correct Answers c
A fuel strainer in a gas fuel train is fitted after the: Correct
Answers main manual shut-off valve
A gauge glass shows the level of a clear, colourless liquid as
very dark, is the ______________ gauge glass.
Select one:
a. Flat
b. Tubular
c. Reflex
d. Bi-colour Correct Answers c
