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
您可能感興趣的試卷
你可能感興趣的試題
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
A.centerline of the pump and the level of the liquid in the suction well when the source of liquid is below the pump
B.centerline of the pump and the suction liquid level when the source of liquid is above the pump
C.centerline of the pump and the level of the discharge liquid
D.liquid levels of the suction and discharge
最新試題
Which of the following statements is correct concerning heat transfer?（）
A salinity indicator is used to determine the （）.
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 （）.
If the thermal bulb of an expansion valve is incorrectly placed at the center of the coil instead of the end, it will （）.
The amount of fluid friction or internal friction inherent in a mineral lubricating oil is reflected as a measure of its （）.
If the head pressure of a reciprocating refrigeration compressor is excessive, （）.
Which of the following problems could cause the high pressure cutout switch to shut down the compressor in a refrigeration system?（）
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?（）
Which of the problems listed would came the discharge temperature of an R-12 refrigeration compressor to increase?（）
If the suction pressure at the refrigeration compressor is below normal, the cause can be（）.