4Th Class Power Engineering B2 C106

Front 1

The application of flame detection devices depends on 1) the type of heating boiler used2) the type of fuel burned3) the quality of feedwater4) which flame it is monitoringA) 1, 2, 3, 4B) 1, 2, 3C) 2, 3, 4D) 1, 3, 4E) 1, 2, 4

Back 1

E

Front 2

A photocell is commonly called a A) thermostatB) thermocoupleC) thermometerD) thermistorE) scanner

Back 2

E

Front 3

If, for any reason, the burner should go out during normal operationA) the fuel burner should be shutoff immediatelyB) the air to the burner should be shutoff immediatelyC) the water to the boiler should be shutoff immediatelyD) the setam leaving the boiler should be shut off immediatelyE) the flue gas leaving the boiler should be shut off immediately

Back 3

A

Front 4

A flame scanner: 1) requires a photoelectric cell 2) responds to temperature changes 3) requires a clear line of sight to the flame 4) produces a steady voltage signalA) all of the above are correctB) 1 & 2 are correctC) 1, 2, & 4 are correctD) 1 & 3 are correctE) none of the above

Back 4

D

Front 5

A thermocouple used in conjunction with a gas valveA) will react to the infrared rays from the flameB) will react to the ultraviolet rays from the flameC) must be insrted in the flame to work effectivelyD) should not be exposed to temperatures over 100 degree CE) measures steam temperature

Back 5

C

Front 6

Thermocouples are connected in series to:A) monitor more than one flame sourceB) increase the sensitivity of the detection systemC) generate a higher voltageD) provide a spare thermocouple in case of failure of oneE) none of the above

Back 6

C

Front 7

Flame rodsA) are used on all heating boilersB) are commonly used with oil-fired boilers onlyC) are commonly used with gas-fired boilers onlyD) are not affected by deposits of carbonE) must be mounted in a vertical position

Back 7

C

Front 8

A lead sulphide cell is sensitive to IR rays and:A) its resistance to current flow varies inversely with ray emissionsB) its resistance to current does not change during operationC) will not sense steady IR rays, only pulsating onesD) will not respond to glowing hot refractoryE) must be replaced at least monthly

Back 8

A

Front 9

Fuel should be shut off immediately if it fails to ignite:A) to save fuelB) to prevent furnace explosionsC) to prevent spillsD) to save powerE) to prevent boiler corrosion

Back 9

B

Front 10

Lead sulphide cells operate when __________ is present.A) no lightB) infraredC) heatD) ultra-violet lightE) flue gas

Back 10

B

Front 11

When a flame failure occurs, the scanner cannot sense a flame so its resistance __________ causing the flame relay to _________.A) decreases, openB) decreases, closeC) increases, openD) increases, closeE) decreases, close to shutoff the fuel supply

Back 11

C

Front 12

High limit temperature controls:A) increase air flow to the boiler if temperature limits are exceededB) open a 3-way mixing valve to add cold water to the hot water to reduce the water temperatureC) are required on steam boilersD) are required under Section II of the ASME CodesE) shut off the fuel if the water temperature is too high

Back 12

E

Front 13

Flame safeguard devices:A) are all unaffected by heatB) should be kept as far away from the fire as possibleC) should not be cleaned except by a qualified servicemanD) should be kept cool enough to be touched by handE) should be tested following the manufacturers instructions

Back 13

E

Front 14

The infrared scanner should be mounted in such a way that its temperature will not exceed __________.A) 100 degree CB) 80 degree CC) 65 degree CD) 50 degree CE) 20 degree C

Back 14

D

Front 15

Which of the following is a flame sensing device?A) thermopileB) heat sensing controlC) stack relayD) cut-off valveE) scanner

Back 15

E

Front 16

Flame rods:A) should be cleaned of deposits regularlyB) should not be exposed to temperatures above 100 degrees CC) should shut off the fuel within four seconds of flame failureD) are very reliable and maintenance freeE) require frequent filing of electrical contacts to prevent corrosion build-up and failure of the device

Back 16

C

Front 17

A flame rod:A) forms an electric circuit with the rod, flame and relayB) is used for gas and oil fired burnersC) forms an electric circuit with the rod, flame and burnerD) senses the temperature of the flameE) is used to light the main burner

Back 17

C

Front 18

To test the flame failure device on a boiler, it is necessary toA) cut-off air supply to the burner firstB) simulate a flame failure conditionC) remove the device from the boilerD) clean the device with water firstE) isolate the boiler first

Back 18

B

Front 19

To test the flame failure device on a boiler, it is necessary toA) cut-off air supply to the burner firstB) simulate a flame failure conditionC) remove the device from the boilerD) clean the device with water firstE) isolate the boiler first

Back 19

B

Front 20

Which of the following is also known as a "cad" cellA) infrared scannerB) thermocoupleC) flame rodD) rectifying photocellE) ultraviolet scanner

Back 20

D

Front 21

To detect the presence of a flame, a flame rod uses the principle that a flameA) is capable of producing heatB) is capable of conducting electricityC) can emit the infrared raysD) can emit the ultraviolet raysE) can emit both the infrared and ultraviolet rays

Back 21

B

Front 22

During the start-up, a boiler equipped with an automatic control system and flame scanning device, the manual main fuel supply valve:A) must be opened before ignition can take placeB) can be opened before the flame scanner sees a flameC) can be opened any time during start-up sequenceD) should be opened as soon as the pilot valve opensE) must be closed before ignition

Back 22

E