A.Volute pump
B.Diffuser pump
C.Regenerative pump
D.All of the above
您可能感興趣的試卷
你可能感興趣的試題
A.mixed-flow
B.axial-flow
C.centrifugal
D.displacement
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
最新試題
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 amount of fluid friction or internal friction inherent in a mineral lubricating oil is reflected as a measure of its （）.
When a refrigeration compressor has developed a high head pressure as a result of a refrigerant overcharge, you should （）.
A pressure drop through the refrigerant liquid line may cause （）.
The rate of heat transfer between the hot and cold fluids passing through a shell-and-tube type heat exchanger will （）.
An internal bypass is provided on some hydraulic system suction strainers to help reduce the possibility of （）.
The general purpose of a heat exchanger is to （）.
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?（）
If the head pressure of a reciprocating refrigeration compressor is excessive, （）.