A.directly increase the pressure of the liquid being pumped
B.directly increase the velocity of the liquid being pumped
C.convert the potential energy of the liquid to kinetic energy
D.separate air from the liquid being pumped
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A.overheated compressor bearings
B.excess lube oil viscosity
C.carbon deposits on the compressor piston rings
D.wax crystals forming in the lubricant
A.electric motor
B.volute
C.impeller
D.diffusion nozzle
A.expansion valve to overfeed
B.compressor to knock
C.water regulating valve to fail
D.crankcase drains to plug
A.poor distillate quality
B.reduced evaporator capacity
C.low brine concentration
D.improper vacuum regulation
A.refrigerant boiling out of solution from the lube oil
B.liquid refrigerant flooding the compressor and system
C.lube oil viscosity being reduced by refrigerant dilution
D.compressor suction pressure suddenly increasing
最新試題
One cause of high head pressure occurring in a refrigeration system can be （）.
Thermostatic expansion valves can be adjusted for （）.
If the head pressure of a reciprocating refrigeration compressor is excessive, （）.
A gradual decrease in the discharge pressure of an operating hydraulic pump can be caused by （）.
If the relief valve on the discharge side of a hydraulic pump lifts, the cause could be （）.
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 （）.
A grease gun is generally used to lubricate a （）.
The amount of fluid friction or internal friction inherent in a mineral lubricating oil is reflected as a measure of its （）.
If the thermal bulb of an expansion valve is incorrectly placed at the center of the coil instead of the end, it will （）.
Who is responsible for ensuring that someone is assigned to close the watertight doors in an emergency?（）