Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
19 Cards in this Set
- Front
- Back
|
On a packaged boiler a number of electrical switches connected in series can be categorized as
a) controls b) interlocks c) start-up devices d) programmer controls e) detectors |
B
|
|
|
A combustion air proving switch a) senses O content of the air 2 b) senses flue gas pressure c) detects O in flue gas 2 d) senses windbox pressure e) senses air temperature |
D
|
|
|
A lead sulphide cell is sensitive to IR rays and a) its resistance to current flow varies inversely with ray emissions b) its resistance to current does not change during operation c) will not sense steady IR rays, only pulsating ones d) will not respond to glowing hot refractory e) must be replaced at least monthly |
A
|
|
|
To operate the type of flame failure device which incorporates a lead sulphide cell, it must receive a) heat from flame b) ultraviolet rays c) infrared rays d) heat and radiation e) a digital signal |
C
|
|
|
The function of a flame failure device is to a) shut off the fuel supply when the pressure gets too high b) shut off the fuel when the burner flame goes out c) shut off the fuel when the fuel temperature is high d) shut off the feedwater supply to the boiler e) de-energize the fan and feedwater systems |
B
|
|
|
Which of the following is a flame sensing device? a) thermopile b) heat sensing control c) stack relay d) cut-off valve e) scanner |
E
|
|
|
A flame failure device a) must be installed on every high pressure boiler b) will shut off the steam leaving the boiler c) will control the pressure of the boiler d) will shut off the fuel to the burner e) will shut down the flame in the boiler |
D
|
|
|
Boiler modulating feedwater control flow rate depends on a) level set point b) control valve position c) actual level d) feedwater pressure e) set point, level, and valve position |
E
|
|
|
With single element feedwater control the level transmitter output is a) received by a final element b) proportional to drum level c) sent to a selector station d) constant regardless of level e) a function of steam flow |
B
|
|
|
The second element of a two element feedwater control system compensates for or offsets a) level variation b) differential feedwater pressure c) differential steam flow rate d) feedwater temperature variation e) shrink and swell |
E
|
|
|
A boiler control transfer or selector station a) can be used to manually override automatic control loops b) can be changed from manual to automatic without balancing c) is located upstream of the controller in a control loop d) output is directed to the primary element of a loop e) must be operated in manual mode for only short periods |
A
|
|
|
An automatic feedwater regulator is used to a) take the place of the boiler feed pump b) activate the low water fuel cut off c) maintain a constant water level in the boiler d) control the chemical feed treatment to the boiler e) control the feedwater pump output |
C
|
|
|
In a two element feedwater control the following items are measured: a) boiler water level and steam flow b) feedwater flow and steam flow c) boiler water level and feedwater flow d) boiler water level and fuel flow e) temperature and volume of feedwater |
A
|
|
|
On a steam boiler with single element feedwater control, the following item is measured: a) steam flow b) feedwater flow c) boiler water level d) fuel flow e) feedwater pressure |
C
|
|
|
An automatic boiler ON-OFF or operating control switch has an adjustment for cut-in or cut-out value and another for a) a differential between the two b) manual or automatic control c) rate of modulation d) high steam pressure limit e) rate of feedback |
A
|
|
|
A packaged steam boiler modulating combustion control system will routinely a) maintain drum level within a desired range b) maintain flue gas temperature at some set point c) alter fuel flow without changing the air flow d) satisfy all load demands regardless of capacity e) maintain boiler steam pressure within a desired range |
E
|
|
|
Modulating combustion control will a) change air and fuel flow proportionally to steam pressure change b) always be at set point when demand is at 50% c) alter only the air flow if a selector station is on manual d) respond to changes in atmospheric pressure e) always be a cascading control system |
A
|
|
|
Modulating pressure control a) will shut down and start up the burner b) will control the fuel and air flow to the boiler c) will control the temperature of the furnace d) can be used on small boilers only e) will control the pressure of the boiler |
B
|
|
|
Modulating combustion control on a heating boiler is accomplished by a) shutting down or lighting up the burner as pressure or temperature rises or falls b) regulating the air flow to control combustion c) changing the amount of fuel and air to the burner d) opening or closing the forced draft damper e) regulating the fuel and feedwater flow |
C
|
