A.misalignment or worn main bearings
B.insufficient cylinder lubrication
C.defective or poorly fitted valves
D.all of the above
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A.They make it easier to replace the pump shaft packing
B.They can be economically replaced as they wear out
C.They can be removed when it is necessary to lighten the weight of the pump
D.They increase the strength of the shaft
A.superheated
B.saturated
C.condensed
D.convected
A.radially from the shaft
B.parallel to each other and to the shaft
C.parallel to each other but at a right angle to the shaft
D.at an angle to each other and to the shaft
A.3 or 5
B.5 or 7
C.7 or 9
D.9 or 11
A.sensible heat
B.latent heat
C.total heat
D.residual heat
最新試題
A salinity indicator is used to determine the （）.
Which of the following problems could cause the high pressure cutout switch to shut down the compressor in a refrigeration system?（）
If the head pressure of a reciprocating refrigeration compressor is excessive, （）.
The temperature differential occurring between the inlet temperature of the fluid to be cooled and the outlet temperature of the cooling medium in a shell-and-tube heat exchanger is greatest in which of the flow designs listed?（）
The usual symptoms of cavitation in a centrifugal pump is （）.
Which of the following statements is correct concerning heat transfer?（）
Heavy wear in a particular area of the inner circumference of a packing ring may be caused by （）.
Which of the problems listed would came the discharge temperature of an R-12 refrigeration compressor to increase?（）
If the relief valve on the discharge side of a hydraulic pump lifts, the cause could be （）.
The major source of chemical contaminants in hydraulic fluid is （）.