A.repack all valve stems
B.lubricate it prior to use
C.replace the foundation bolts
D.balance the warping heads
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A.blue
B.green
C.orange
D.purple
A.blue
B.green
C.orange
D.purple
A.excessive condenser cooling water
B.warm food in the refrigerator
C.a shortage of refrigerant
D.s shortage of compressor oil
A.either all the way open or all the way closed
B.normally open
C.throttled depending on load
D.controlled by suction pressure
When a hydraulic vane pump is working, which of the following is in contact with the vanes?（）
(1) the rotor
(2) the internal surface of the housing
(3) the external surface of the housing
A.(1) only
B.(2) only
C.(1) and (2)
D.(1), (2) and (3)
最新試題
One cause of high head pressure occurring in a refrigeration system can be （）.
The amount of fluid friction or internal friction inherent in a mineral lubricating oil is reflected as a measure of its （）.
Which of the following statements is correct concerning heat transfer?（）
The output volume of a positive fixed displacement pump can be changed only by （）.
A grease gun is generally used to lubricate a （）.
When the steering gear is in operation, you should （）.
The rate of heat transfer between the hot and cold fluids passing through a shell-and-tube type heat exchanger will （）.
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 （）.
If the viscosity of the liquid being transferred remains constant as the discharge pressure increases, the rotary pump （）.