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
A salinity indicator is used to determine the （）.
A pressure drop through the refrigerant liquid line may cause （）.
The general purpose of a heat exchanger is to （）.
An excessive charge of refrigerant in an air-cooled refrigeration system can cause （）.
The usual symptoms of cavitation in a centrifugal pump is （）.
An internal bypass is provided on some hydraulic system suction strainers to help reduce the possibility of （）.
Which of the following problems could cause the high pressure cutout switch to shut down the compressor in a refrigeration system?（）
Low compressor head pressure in a refrigeration system can be caused by（）.
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 （）.
Which of the listed pumps is NOT a positive displacement pump?（）