A.Energy can be created or destroyed
B.Energy may not be transformed
C.The total quantity of energy in the universe is always the same
D.None of the above
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A.evaporator
B.compressor
C.expansion valve
D.condenser
A.has continuously for a long period
B.suction pressure is below normal
C.oil level is below normal
D.starts after a long idle period
A.protect the pump from fine soluble contaminants
B.prevent solid particles from entering the pump
C.prevent solid particles from entering the filter
D.protect the directional control valves
A.Feed-water heater internal tube surfaces
B.Internal distillate cooler tubes
C.Flash chamber vertical surfaces
D.Distilling condenser tubes
A.Reduction of friction
B.Insulation of hot surfaces
C.Lubrication of moving parts
D.Elevation of cooler outlet temperatures
最新試題
An increasing head pressure in a refrigeration system, without any corresponding change in the cooling water inlet temperature, would probably be caused by （）.
Which of the following statements is correct concerning heat transfer?（）
A gradual decrease in the discharge pressure of an operating hydraulic pump can be caused by （）.
Pitting in the suction areas of a centrifugal pump bronze impeller is usually caused by （）.
When the steering gear is in operation, you should （）.
The general purpose of a heat exchanger is to （）.
If the thermal bulb of an expansion valve is incorrectly placed at the center of the coil instead of the end, it will （）.
The major source of chemical contaminants in hydraulic fluid is （）.
The rate of heat transfer between the hot and cold fluids passing through a shell-and-tube type heat exchanger will （）.
Which of the following problems could cause the high pressure cutout switch to shut down the compressor in a refrigeration system?（）