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)
您可能感興趣的試卷
你可能感興趣的試題
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
A.pump entry branch
B.outlet pipe
C.impeller
D.None of the above is true
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
最新試題
A salinity indicator is used to determine the （）.
If the suction pressure at the refrigeration compressor is below normal, the cause can be（）.
The amount of fluid friction or internal friction inherent in a mineral lubricating oil is reflected as a measure of its （）.
Which of the following statements is correct concerning heat transfer?（）
An internal bypass is provided on some hydraulic system suction strainers to help reduce the possibility of （）.
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?（）
A gradual decrease in the discharge pressure of an operating hydraulic pump can be caused by （）.
The major source of chemical contaminants in hydraulic fluid is （）.
If the head pressure of a reciprocating refrigeration compressor is excessive, （）.
Heavy wear in a particular area of the inner circumference of a packing ring may be caused by （）.