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单选题
An increase in rotor clearances in a rotary pump will （）.
A
increase discharge pressure
B
decrease pump capacity
C
decrease pump cavitation
D
decrease reaction ring clearance
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An increase in rotor clearances in a rotary pump will ______.A.increase discharge pressureB.decrease pump capacityC.decrease pump cavitationD.decrease reaction ring clearance
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The high discharge pressure of the rotary pumps permits a larger volume of fluid per unit time than the reciprocating pumpB
Rotary pumps are capable of pumping more fluid than reciprocating pumps of the same weightC
Rotary pumps occupy only one-half the space of reciprocating pumpsD
Rotary pumps eliminate discharge slippage of the pumped liquid, while this does not hold true for a reciprocating pump
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noise and vibrationB
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考题
单选题Operating a rotary pump at speeds in excess of design requirements could cause（）.A
decreased clearances between rotating partsB
decreased slippage to the suction side of the pumpC
air binding in the discharge portsD
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result in decreased acceleration time onlyB
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cause a greater starting torqueD
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考题
单选题The basic function of the centrifugal pump impeller is to （）.A
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单选题Increasing the speed of a rotary pump above its rated speed will result in which of the following conditions to occur?（）A
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connection must guide the liquid to the lantern ringsD
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A radial piston pump houses sliding pistons in a stationary cylinder block through which passes a rotating pintle or ported shaftC
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DramB
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单选题When a hydraulic vane pump is working, which of the following is in contact with the vanes?（） (1) the rotor (2) the internal surface of the housing (3) the external surface of the housingA
(1) onlyB
(2) onlyC
(1) and (2)D
(1), (2) and (3)
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leaking delivery valveB
excessive bearing end playC
plugged injector spray holeD
increased plunger stroke
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（1）B
（1）and（2）C
（2）D
neither（1）nor（2）
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单选题As for a hydraulic vane pump, which of the following is in contact with the vanes during working: （） (1)the rotor (2)the pump shaft (3)the external surface of the housingA
(1) onlyB
(2) onlyC
(1) and (2)D
(1),(2)and(3)
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单选题Why are removable sleeves installed on centrifugal pump shafts?（）A
They make it easier to replace the pump shaft packingB
They can be economically replaced as they wear outC
They can be removed when it is necessary to lighten the weight of the pumpD
They increase the strength of the shaft
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