A.mixed-flow
B.axial-flow
C.centrifugal
D.displacement
您可能感興趣的試卷
你可能感興趣的試題
Which of the following operating features do displacement pumps bear if they are working under no-cavitation condition?（）
(1) output is almost directly proportional to speed
(2) they are self-priming
(3) they will develop a discharged pressure equal to the resistance to be overcome, irrespective of speed
A.（1）and（2）
B.（2）and（3）
C.（1）and（3）
D.（1），（2）and（3）
Which of the following pumps will build up a bursting pressure or stall their motors if the discharge valves are closed?（）
(1) gear
(2) centrifugal
(3) screw
A.（1）and（2）
B.（1），（2）and（3）
C.（1）and（3）
D.（2）and（3）
A.providing the impeller with balancing holes
B.the use of symmetrical impeller
C.neither A nor B
D.either A or B
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)
最新試題
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 （）.
The general purpose of a heat exchanger is to （）.
Low compressor head pressure in a refrigeration system can be caused by（）.
The rate of heat transfer from a hot region to a cold region is affected most by the （）.
The control mode in which the final control element is moved from one of two flexed positions to the other is known as （）.
A grease gun is generally used to lubricate a （）.
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?（）
Who is responsible for ensuring that someone is assigned to close the watertight doors in an emergency?（）
The major source of chemical contaminants in hydraulic fluid is （）.
An increasing head pressure in a refrigeration system, without any corresponding change in the cooling water inlet temperature, would probably be caused by （）.