A.Impeller
B.Electric motor
C.Volute
D.Eye
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A.carbon deposits on the compressor suction valves
B.the evaporator temperature to increase
C.rapid corrosion of the thermal expansion valve
D.no operating problems
A.increases brine density
B.increases distillate salinity
C.reduces metal corrosion
D.reduces heat transfer
A.positive head
B.negative suction head
C.mechanical seal
D.vent valve attached to the casing at the top of the volute
A.gate valve
B.globe valve
C.check valve
D.plug cock
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
最新試題
Which of the following statements is correct concerning heat transfer?（）
The output volume of a positive fixed displacement pump can be changed only by （）.
The rate of heat transfer between the hot and cold fluids passing through a shell-and-tube type heat exchanger will （）.
The usual symptoms of cavitation in a centrifugal pump is （）.
Low compressor head pressure in a refrigeration system can be caused by（）.
If the suction pressure at the refrigeration compressor is below normal, the cause can be（）.
The major source of chemical contaminants in hydraulic fluid is （）.
The rate of heat transfer from a hot region to a cold region is affected most by the （）.
Which of the problems listed would came the discharge temperature of an R-12 refrigeration compressor to increase?（）
Heavy wear in a particular area of the inner circumference of a packing ring may be caused by （）.