A.injector
B.positive displacement
C.centrifugal
D.centripetal
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A.injector pumps
B.positive displacement pumps
C.centrifugal pump
D.centripetal pumps
A.the mechanical seal
B.packed stuffing boxes
C.either A or B
D.neither A nor B
As for a hydraulic vane pump, which of the following is in contact with the vanes during working: （）
(1)the rotor
(2)the pump shaft
(3)the external surface of the housing
A.(1) only
B.(2) only
C.(1) and (2)
D.(1),(2)and(3)
A.circular
B.elliptical
C.rectangular
D.hexagon
A.suction
B.exhaust
C.pressure
D.discharge
最新試題
One cause of high head pressure occurring in a refrigeration system can be （）.
If the relief valve on the discharge side of a hydraulic pump lifts, the cause could be （）.
Which of the following problems could cause the high pressure cutout switch to shut down the compressor in a refrigeration system?（）
Pitting in the suction areas of a centrifugal pump bronze impeller is usually caused by （）.
Thermostatic expansion valves can be adjusted for （）.
When the steering gear is in operation, you should （）.
Which of the listed pumps is NOT a positive displacement pump?（）
Which of the problems listed would came the discharge temperature of an R-12 refrigeration compressor to increase?（）
The control mode in which the final control element is moved from one of two flexed positions to the other is known as （）.
The major source of chemical contaminants in hydraulic fluid is （）.