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What is the function of wearing rings found on some centrifugal pumps ________．
A.Absorb erosion of high velocity discharge stream
B.Seal pump shaft against entry of air
C.Isolate the outlet side from the inlet side
D.Dampen the turbulent discharge flow
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更多 “ What is the function of wearing rings found on some centrifugal pumps ________．A.Absorb erosion of high velocity discharge streamB.Seal pump shaft against entry of airC.Isolate the outlet side from the inlet sideD.Dampen the turbulent discharge flow ” 相关考题
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If a centrifugal pump is driven by a constant speed electric motor and produces a discharge pressure less than designed, the cause is probably ______.A.excessive pump speedB.excessive suction headC.worn wearing ringsD.gross pump misalignment
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What causes cavitation in a centrifugal pump ________．A.Vapor pockets in the flow streamB.Rough impeller surfacesC.Worn wearing ringsD.Heavy fluid in the flow stream
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单选题If a centrifugal pump vibrates and is noisy when operating, the cause could be （）.A
worn gland sealing shaftB
worn wearing ringsC
a bent shaftD
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单选题What is the function of wearing rings found on some centrifugal pumps? （）A
Absorb erosion of high velocity discharge streamB
Seal pump shaft against entry of airC
Isolate the outlet side from the inlet sideD
Dampen the turbulent discharge flow
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单选题What is a function of the wearing rings used in most centrifugal pumps?（）A
Absorb erosion of high velocity discharge streamB
Seal pump shaft against entry of airC
Isolate the discharge side from the suction sideD
Dampen the turbulent discharge flow
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starting the engine while hotB
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nonpositive displacementC
positive displacementD
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单选题What is a characteristic of all centrifugal cargo pumps? （）A
They are self-primingB
Decreasing the speed of rotation will decrease the discharge pressureC
Opening the discharge valve wider will increase the discharge pressureD
All of the above
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Increases the sludge forming tendency of lube oilB
Prevents the accumulation of combustible gasesC
Improves lube oil coolingD
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单选题Centrifugal pumps have what advantage(s) over reciprocating pumps?（）.A
They are less expensiveB
They are smaller for equivalent pumping abilityC
They pump more cargo in less timeD
All of the above
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单选题Under centrifugal pumps are the volute, diffuser, mixed-flow, axial flow and （） or regenerative types.A
reciprocatingB
hydraulicC
turbineD
vane
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单选题The capacity of a centrifugal pump can be increased by the installation of a larger diameter impeller Another means of increasing the pump capacity is to （）.A
increase speedB
increase the size of the cardent assemblyC
reduce wearing ring clearancesD
change the pump to a close coupled arrangement
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单选题If you were operating a centrifugal water service pump with worn wearing rings, the （）.A
pump would be very noisyB
pump would vibrate excessivelyC
pump would develop insufficient flowD
stuffing box would leak excessively
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单选题If a centrifugal pump is driven by a constant speed electric motor and produces a discharge pressure less than designed, the cause is probably（）.A
excessive pump speedB
excessive suction headC
worn wearing ringsD
gross pump misalignment
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单选题To absorb the wear resulting from impeller rotation and abrasives in the liquid, a centrifugal pump is usually fitted with （）.A
lantern ringsB
bearingsC
easing volutesD
wearing rings
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单选题Lube oil pumps taking suction from the sump of most small marine engines are usually （）.A
of the diaphragm typeB
of the centrifugal typeC
of the positive displacement typeD
independently driven by electric motors
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单选题If the capacity of a centrifugal pump decreases gradually over a long period of time, you should replace the （）.A
packing glandB
mechanical sealsC
lantern ringsD
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单选题The piston rings if found worn out （） and supplied by shipchandler.A
must replaceB
must to be equippedC
has to be repairedD
have to be renewed
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单选题The purpose of the wearing rings used in a centrifugal pump is to （）.A
prevent an internal explosion in the pump when it is overheatedB
enable a visual inspection of the pump while it is runningC
insure a proper alignment of the pump coupling to the driverD
accommodate for friction between the impeller and the easing
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单选题When installed for bilge pumping or ballast duty, centrifugal pumps require a （） to remove air from the suction pipe.A
air chamberB
head lankC
primerD
prime mover
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单选题Which of the following pumps belongs to centrifugal pump?（）A
Piston pumpB
Screw pumpC
Diffuser pumpD
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单选题To maintain design discharge pressure from a centrifugal pump, the design clearance must be maintained between the （）.A
shaft and impellerB
motor and pump shaftC
casing and impeller wearing ringsD
lantern ring and impeller
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单选题Which of the materials listed is used as the dynamic seal material on mechanical seals installed on most centrifugal pumps used in water service?（）A
CopperB
Copper and carbonC
CarbonD
Bronze
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单选题Which features of a centrifugal pump reduce the need for renewing worn impellers and pump casings?（）A
Close radial clearance between impeller hub and casingB
Low rotational speed of impellerC
Removable end plateD
Replaceable impeller and casing wearing rings
考题
单选题Centrifugal pumps, however, can be designed with a number of impellers （） to attain a large amount of liquid.A
in seriesB
in parallelC
assembledD
together
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单选题Which of the listed conditions can lead to cavitation气穴in a centrifugal pump?（）A
Vapor pockets formed in the suction flow streamB
Rough easing volute surfacesC
Worn wearing ringsD
Heavy fluid in the flow stream
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