A.blue
B.green
C.orange
D.purple
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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)
A.Control of evaporation
B.A separate means to prevent feed-water contamination
C.Power circulating pump
D.Super-heater
最新試題
A pressure drop through the refrigerant liquid line may cause （）.
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 （）.
When the steering gear is in operation, you should （）.
Pitting in the suction areas of a centrifugal pump bronze impeller is usually caused by （）.
Which of the listed pumps is NOT a positive displacement pump?（）
The control mode in which the final control element is moved from one of two flexed positions to the other is known as （）.
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 （）.
A salinity indicator is used to determine the （）.