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
An excessive charge of refrigerant in an air-cooled refrigeration system can cause （）.
The rate of heat transfer between the hot and cold fluids passing through a shell-and-tube type heat exchanger will （）.
The general purpose of a heat exchanger is to （）.
The amount of fluid friction or internal friction inherent in a mineral lubricating oil is reflected as a measure of its （）.
One cause of high head pressure occurring in a refrigeration system can be （）.
If the viscosity of the liquid being transferred remains constant as the discharge pressure increases, the rotary pump （）.
Which of the problems listed would came the discharge temperature of an R-12 refrigeration compressor to increase?（）
The control mode in which the final control element is moved from one of two flexed positions to the other is known as （）.
The temperature differential occurring between the inlet temperature of the fluid to be cooled and the outlet temperature of the cooling medium in a shell-and-tube heat exchanger is greatest in which of the flow designs listed?（）
If the thermal bulb of an expansion valve is incorrectly placed at the center of the coil instead of the end, it will （）.