A.to fill 2 tanks at the same time
B.to use pump at a higher pressure
C.to return liquid to suction side if discharge valve is closed
D.All of the above are true
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A.injector
B.positive displacement
C.centrifugal
D.centripetal
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
最新試題
If the suction pressure at the refrigeration compressor is below normal, the cause can be（）.
A salinity indicator is used to determine the （）.
When the steering gear is in operation, 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 usual symptoms of cavitation in a centrifugal pump is （）.
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Which of the following statements is correct concerning heat transfer?（）
The rate of heat transfer between the hot and cold fluids passing through a shell-and-tube type heat exchanger will （）.
The major source of chemical contaminants in hydraulic fluid is （）.
If the viscosity of the liquid being transferred remains constant as the discharge pressure increases, the rotary pump （）.