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单选题
The basic function of the centrifugal pump impeller is to （）.
A
directly increase the pressure of the liquid being pumped
B
directly increase the velocity of the liquid being pumped
C
convert the potential energy of the liquid to kinetic energy
D
separate air from the liquid being pumped
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更多 “单选题The basic function of the centrifugal pump impeller is to （）.A directly increase the pressure of the liquid being pumpedB directly increase the velocity of the liquid being pumpedC convert the potential energy of the liquid to kinetic energyD separate air from the liquid being pumped” 相关考题
考题
It is possible to mount a double suction centrifugal pump impeller with the vanes facing in the wrong direction. This would cause the pump ______.A.head capacity to improveB.discharge to be reversedC.efficiency to decreaseD.slippage to decrease
考题
A centrifugal pump may fail to deliver water when first started if the ______.A.water seal pipe is pluggedB.pump is not primedC.seal ring is properly locatedD.impeller is flooded
考题
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
考题
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
考题
单选题With respect to centrifugal pump impellers, which of the following descriptions represents the correct centrifugal pump classification? （）A
Single stage or multistageB
High pressure or low pressureC
Open or close coupledD
Horizontal or vertical
考题
单选题Which of the following statements is correct with regards to the operation of a centrifugal cargo pump?（）A
Oil is discharged from the impeller through the outletB
Gravity causes the oil to flow toward the dischargeC
The self-priming feature of the centrifugal pump enables it to draw its own suction as it startsD
The discharge capacity varies directly with the speed of the impeller
考题
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
考题
单选题The function of a centrifugal pump double volute casing is to （）.A
reduce radial thrust to the impellerB
double the liquid velocity through the pump when compared to a single voluteC
reduce hydraulic end thrustD
provide the effect of multi-staging
考题
单选题A double suction centrifugal pump impeller has been installed in the reverse direction, and will （）.A
have a greater head capacityB
operate with increased impeller efficiencyC
discharge through the suction side of the pump casingD
require more power to run the shaft
考题
单选题A multistage centrifugal pump can be BEST described as having （）.A
two or more impellers housed together in one casing and mounted on a single shaftB
a single stepped impeller mounted in a progressively staged casingC
a large radial clearance between the impeller and casing to prevent overheating due toD
an increase in the discharge velocity of the liquid with a corresponding decrease in pressure through the stages
考题
单选题Pitting in the suction areas of a centrifugal pump bronze impeller is usually caused by （）.A
cavitationB
electrolysisC
abrasionD
corrosion
考题
单选题Increasing the speed of a centrifugal pump will result in an increase in its capacity Another means of increasing the capacity of a centrifugal pump is to increase the （）.A
diameter of the discharge piping, with all other factors remaining the sameB
diameter of the suction piping, with all other factors remaining the sameC
width of the impeller onlyD
diameter of the impeller
考题
单选题Increasing the speed of a centrifugal pump will result in an increase in its capacity in its capacityAnother means of increasing the capacity pump is to increase the（）A
diameter of the discharge piping, with all other factors remaining the sameB
diameter of the suction piping, with all other factors remaining the sameC
width of the impeller onlyD
diameter of the impeller
考题
单选题One of the main functions of wearing rings, as used in a centrifugal pump, is to （）.A
maintain radial alignment between the pump impeller and casingB
absorb all impeller shaft end thrustC
prevent water leakage to the atmosphereD
prevent wear of the pump casing and/or impeller
考题
单选题A centrifugal impeller consists of a number of vanes curving （） from the direction of rotation.A
backwardsB
forwardsC
upwardD
downwards
考题
单选题Attempts are made to eliminate axial thrust in centrifugal pump by （）.A
providing the impeller with balancing holesB
the use of symmetrical impellerC
neither A nor BD
either A or B
考题
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
考题
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
考题
单选题It is possible to mount a double suction centrifugal pump impeller with the vanes facing in the wrong directionThis would cause the pump （）.A
head capacity to improveB
discharge to be reversedC
efficiency to decreaseD
slippage to decrease
考题
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
考题
单选题Which of the listed statements is correct concerning the starting of centrifugal pumps?（）A
They should always be started with the discharge valve closedB
They should always be started with the discharge valve openedC
A priming pump is always required to flood the impeller suctionD
They should always be started with the sealing line valves closed
考题
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
考题
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The discharge head of a centrifugal pump will vary directly with the （）.A
change in impeller diameterB
square of the impeller diameterC
cube of the impeller diameterD
impeller efficiency for large changes in the size of the impeller
考题
单选题The discharge rate or capacity of a centrifugal pump will vary directly as the （）.A
change in the impeller diameterB
square of the impeller radiusC
cube of the impeller diameterD
impeller efficiency for large changes in its size
考题
单选题On modern ships, centrifugal pump with a self-primer has replaced reciprocating pump as bilge pump because（）A
centrifugal pump is cheaper than reciprocating pumpB
the size of centrifugal pump with same capacity is smaller than that of reciprocating pumpC
centrifugal pump makes maintenance easier than reciprocating pump doesD
all of the above
考题
单选题A centrifugal pump vibrates excessively during operationUpon disassembling the pump it is found that the impeller is out of balanceWithout an available spare, you should （）.A
drill holes through the heavy side of the impeller until it balancesB
weld counterweights to the light side of the impellerC
remove metal from the heavy side by machining in a latheD
acid wash and serape the heavy side until it balances
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