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
The control mode in which the final control element is moved from one of two flexed positions to the other is known as （）.
If the viscosity of the liquid being transferred remains constant as the discharge pressure increases, the rotary pump （）.
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 listed pumps is NOT a positive displacement pump?（）
The rate of heat transfer between the hot and cold fluids passing through a shell-and-tube type heat exchanger will （）.
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 （）.
Who is responsible for ensuring that someone is assigned to close the watertight doors in an emergency?（）
If the thermal bulb of an expansion valve is incorrectly placed at the center of the coil instead of the end, it will （）.
If the head pressure of a reciprocating refrigeration compressor is excessive, （）.