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 gradual decrease in the discharge pressure of an operating hydraulic pump can be caused by （）.
Which of the listed pumps is NOT a positive displacement pump?（）
The output volume of a positive fixed displacement pump can be changed only by （）.
On tank vessels equipped with power operated cargo tank valves, the type of power operator most commonly used is （）.
The rate of heat transfer from a hot region to a cold region is affected most by the （）.
Which of the following problems could cause the high pressure cutout switch to shut down the compressor in a refrigeration system?（）
An excessive charge of refrigerant in an air-cooled refrigeration system can cause （）.
The general purpose of a heat exchanger is to （）.
Which of the following statements is correct concerning heat transfer?（）
The major source of chemical contaminants in hydraulic fluid is （）.