A.providing the impeller with balancing holes
B.the use of symmetrical impeller
C.neither A nor B
D.either A or B
您可能感興趣的試卷
你可能感興趣的試題
A.throttling the pressure line
B.changing the speed of the rotor
C.either A or B
D.None of the above is true
Which of the following pumps are self-priming, and can deal with liquid from a level below the pump（）
(1) ejector
(2) screw
(3) centrifugal
A.(1)only
B.(1)and(2)
C.(1),(2)and(3)
D.(2)and(3)
A.centrifugal
B.plunger
C.injector
D.water
A.discharges into a gradually widening channel
B.has stationary diffuser vanes
C.produces no kinetic energy
D.All of the above are true
A.Piston pump
B.Screw pump
C.Diffuser pump
D.Water-ring pump
最新試題
If the viscosity of the liquid being transferred remains constant as the discharge pressure increases, the rotary pump （）.
If the suction pressure at the refrigeration compressor is below normal, the cause can be（）.
Who is responsible for ensuring that someone is assigned to close the watertight doors in an emergency?（）
If you are given the job of adding hydraulic fluid to a mooring winch, and are not certain as to the type of fluid to use, you should （）.
If the relief valve on the discharge side of a hydraulic pump lifts, the cause could be （）.
The usual symptoms of cavitation in a centrifugal pump is （）.
The control mode in which the final control element is moved from one of two flexed positions to the other is known as （）.
An internal bypass is provided on some hydraulic system suction strainers to help reduce the possibility of （）.
An increasing head pressure in a refrigeration system, without any corresponding change in the cooling water inlet temperature, would probably be caused by （）.
A gradual decrease in the discharge pressure of an operating hydraulic pump can be caused by （）.