A.in series
B.in parallel
C.either A or B
D.None of the above is tree
您可能感興趣的試卷
你可能感興趣的試題
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 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
A.reduce
B.rise
C.raise
D.fall
A.increase discharge pressure
B.increase suction vacuum
C.develop pulsation flow
D.keep a steady rate of flow
A.slack enough to allow slight leakage of fluid
B.slightly clocked
C.brought up tight so as not to allow any leakage
D.fitted with a relief valve
最新試題
Heavy wear in a particular area of the inner circumference of a packing ring may be caused by （）.
A salinity indicator is used to determine the （）.
When the steering gear is in operation, you should （）.
Who is responsible for ensuring that someone is assigned to close the watertight doors in an emergency?（）
If the thermal bulb of an expansion valve is incorrectly placed at the center of the coil instead of the end, it will （）.
Which of the problems listed would came the discharge temperature of an R-12 refrigeration compressor to increase?（）
A grease gun is generally used to lubricate a （）.
An increasing head pressure in a refrigeration system, without any corresponding change in the cooling water inlet temperature, would probably be caused by （）.
An excessive charge of refrigerant in an air-cooled refrigeration system can cause （）.
If the viscosity of the liquid being transferred remains constant as the discharge pressure increases, the rotary pump （）.