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
最新試題
When the steering gear is in operation, you should （）.
Heavy wear in a particular area of the inner circumference of a packing ring may be caused by （）.
The usual symptoms of cavitation in a centrifugal pump is （）.
One cause of high head pressure occurring in a refrigeration system can be （）.
If the suction pressure at the refrigeration compressor is below normal, the cause can be（）.
The temperature differential occurring between the inlet temperature of the fluid to be cooled and the outlet temperature of the cooling medium in a shell-and-tube heat exchanger is greatest in which of the flow designs listed?（）
The control mode in which the final control element is moved from one of two flexed positions to the other is known as （）.
The general purpose of a heat exchanger is to （）.
If the viscosity of the liquid being transferred remains constant as the discharge pressure increases, the rotary pump （）.
If the thermal bulb of an expansion valve is incorrectly placed at the center of the coil instead of the end, it will （）.