A.ensure feed water flow into the boiler
B.keep the steam drum pressure high
C.prevent water hammer in the feed line
D.help the feed water flash to steam
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A.take no measures
B.extinguish the fire as soon as possible
C.feed water to the boiler
D.open the blow down valve
A.feed pump suction line
B.hot well
C.shell of the feed heater
D.feed lines to the boiler
A.rise when the steam pressure is increased
B.remain constant as long as the feed pump operates
C.fall when the steam pressure is decreased
D.vary as the steam demand changes
A.to raise water level
B.only while making steam
C.to remove scum
D.when fire are secured
A.drop as the boiler warms up
B.rise as the boiler warms up
C.remain unchanged until the boiler is hot enough
D.rise and fall with the steam demand
最新試題
Which of the problems listed would came the discharge temperature of an R-12 refrigeration compressor to increase?（）
An excessive charge of refrigerant in an air-cooled refrigeration system can cause （）.
The usual symptoms of cavitation in a centrifugal pump is （）.
When a refrigeration compressor has developed a high head pressure as a result of a refrigerant overcharge, you should （）.
A pressure drop through the refrigerant liquid line may cause （）.
Which of the following problems could cause the high pressure cutout switch to shut down the compressor in a refrigeration system?（）
Heavy wear in a particular area of the inner circumference of a packing ring may be caused by （）.
Thermostatic expansion valves can be adjusted for （）.
If the viscosity of the liquid being transferred remains constant as the discharge pressure increases, the rotary pump （）.
The control mode in which the final control element is moved from one of two flexed positions to the other is known as （）.