单项选择题
A.deformed B.rusted C.cracked D.scaled
Centrifugal pumps can be designed with a number of impe...
单项选择题Centrifugal pumps can be designed with a number of impellers （） to attain a high final delivery pressure.
A.in series B.in parallel C.either A or B D.None of the above is tree
Which of the following pumps are self-priming, and can ...
Which of the following pumps are self-priming, and can deal with liquid from a level below the pump: （） (1)reciprocating (2)vane (3)gear
A.（1）only B.（1）and（2） C.（2）and（3） D.（1），（2）and（3）
Which of the following will be the advantage of a centr...
Which of the following will be the advantage of a centrifugal pump as compared with a reciprocating pump?（） (1) Its discharge is continuous (2) It has no internal valves (3) Upon accidental closing of discharge valve, excessive pressure will not build up
A.（1），（2） B.（2），（3） C.（1），（2），（3） D.（2）only
