A.variable stroke pumps
B.multistage pumps
C.positive displacement pumps
D.triple-ported pumps
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A.mixed-flow pump
B.axial-flow pump
C.centrifugal pump
D.displacement pump
A.on top cover
B.on sides of bowl
C.in drain line on the discs
D.on the discs
A.oil
B.sea water
C.refrigerant
D.fresh water
A.a flash generator
B.a flash evaporator
C.a vacuum boiling evaporator
D.a boiler
A.lower than
B.higher than
C.as much as
D.the same as
最新試題
The rate of heat transfer between the hot and cold fluids passing through a shell-and-tube type heat exchanger will （）.
One cause of high head pressure occurring in a refrigeration system can be （）.
The major source of chemical contaminants in hydraulic fluid is （）.
If the head pressure of a reciprocating refrigeration compressor is excessive, （）.
The amount of fluid friction or internal friction inherent in a mineral lubricating oil is reflected as a measure of its （）.
An excessive charge of refrigerant in an air-cooled refrigeration system can cause （）.
The usual symptoms of cavitation in a centrifugal pump is （）.
An increasing head pressure in a refrigeration system, without any corresponding change in the cooling water inlet temperature, would probably be caused by （）.
If the suction pressure at the refrigeration compressor is below normal, the cause can be（）.
Which of the problems listed would came the discharge temperature of an R-12 refrigeration compressor to increase?（）