A.gate valve
B.globe valve
C.check valve
D.plug cock
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A.At the designed operating temperature, the liquid refrigerant charge has changed to a vapor
B.The liquid refrigerant tends to collect at the bellows or diaphragm and reduces the valve sensitivity
C.The sensing bulb is empty of liquid refrigerant charge at the designed operating temperature
D.The sensing bulb is never emptied of liquid refrigerant under normal operating conditions
A.diaphragm type gage
B.pressure transducer
C.manometer
D.All of the above
A.reduce radial thrust to the impeller
B.double the liquid velocity through the pump when compared to a single volute
C.reduce hydraulic end thrust
D.provide the effect of multi-staging
A.dirt will cause corrosion of bearing
B.bearings will leak oil excessively
C.dirt is very abrasive when mixed with grease
D.grease will become inflammable
A.promote refrigerant dehydration
B.be absorbed in the receiver
C.cause low condensing pressure
D.carry moisture and lead to corrosion
最新試題
Pitting in the suction areas of a centrifugal pump bronze impeller is usually caused by （）.
The general purpose of a heat exchanger is to （）.
One cause of high head pressure occurring in a refrigeration system can be （）.
Thermostatic expansion valves can be adjusted for （）.
Which of the listed pumps is NOT a positive displacement pump?（）
When a refrigeration compressor has developed a high head pressure as a result of a refrigerant overcharge, you should （）.
If you are given the job of adding hydraulic fluid to a mooring winch, and are not certain as to the type of fluid to use, you should （）.
Who is responsible for ensuring that someone is assigned to close the watertight doors in an emergency?（）
When the steering gear is in operation, you should （）.
An excessive charge of refrigerant in an air-cooled refrigeration system can cause （）.