A.centrifugal pumps
B.jet pumps
C.propeller pumps
D.reciprocating pumps
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A.a compressed packing gland
B.lantern tings between the packing rings
C.a liquid seal
D.the stuffing box gland
A.loss of second stage vacuum
B.contamination of the distillate
C.lower feed inlet temperature
D.contamination of the second stage condenser
A.total head
B.discharge head
C.net positive suction head
D.suction head
A.slide block
B.tilting box
C.pintle
D.reaction ring
A.Liquids with different viscosities will always have the same specific gravity
B.Liquids with different viscosities will never have the same specific gravity
C.Viscosity and specific gravity are directly proportional
D.Viscosity and specific gravity are not related in that one does not define or limit the other
最新試題
Which of the following problems could cause the high pressure cutout switch to shut down the compressor in a refrigeration system?（）
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 problems listed would came the discharge temperature of an R-12 refrigeration compressor to increase?（）
The amount of fluid friction or internal friction inherent in a mineral lubricating oil is reflected as a measure of its （）.
The output volume of a positive fixed displacement pump can be changed only by （）.
An internal bypass is provided on some hydraulic system suction strainers to help reduce the possibility of （）.
One cause of high head pressure occurring in a refrigeration system can be （）.
Low compressor head pressure in a refrigeration system can be caused by（）.
A pressure drop through the refrigerant liquid line may cause （）.
If the relief valve on the discharge side of a hydraulic pump lifts, the cause could be （）.