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

题目

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 improve

B.discharge to be reversed

C.efficiency to decrease

D.slippage to decrease

相似考题

1.第二组Displacement pumps are those where the volume of the pump chamber is alternately increased to draw the liquid in from the suction pipe and then decreased to force the liquid out into the delivery pipe. Centrifugal pumps are those wherein an impeller rotating at high speed throws the liquid by centrifugal force from the center to the periphery of the impeller where the liquid is discharged through the delivery outlet.Gear pump consists of two or more meshing gears (spur, single or double helical teeth) enclosed m a close-fitted housing. These are used extensively for pumping fuel oil, lubricating oil and hydraulic oil. When gears are unmeshed on the inlet side, a pressure drop occurs that helps the atmospheric pressure acting on the surface of the oil in the reservoir to force it up the pipe to fill the void, the oil is then transferred around the periphery of the pump housing. As the gear teeth mesh again on the outlet side, they form. a seal that prevents oil from backing up to the inlet, the oil in the void is then be forced out into the discharge line.All vane pumps have a rotor driven within a ring (cam ring) by a drive shaft coupled to a prime mover. A cylindrical rotor with sliding vanes, generally in radial slots, rotates within the ring. The center of the rotor is offset from the center of the ring. In a simple vane pump, as the rotor turns, the vanes are forced outward against the inner surface of the cam ring by centrifugal force. This outward radial movement of the vanes and turning of the rotor causes the chamber between the vanes to increase as the vanes pass further away from the inlet port. This increase in volume results in a lowering of pressure until the atmospheric pressure is sufficient to force oil from the reservoir into the inlet chamber. Oil from the inlet is swept away by the vanes toward the outlet port through a decreasing series of chambers until it is forced through the outlet port. A vane pump of balanced design has an elliptical cam ring so that two pumping chambers are formed. This pump is in hydraulically balance, since the two intake and two outlet ports are diametrically opposed to each other. Therefore the side loads exerted on the rotor cancel out, thereby increasing bearing lift and permitting high operating pressure.According to the last sentence of paragraph 1, from where the liquid is discharged through the delivery outlet?A.from the eye of the impellerB.from passage of impellerC.from the periphery of the impellerD.from the impeller

2.All of the following steps are taken in starting a centrifugal pump，EXCEPT to ______．A.Set the relief valveB.Check the lubrication systemC.Vent the pump casingD.Open the pump suction and discharge valves

3.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

4.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

更多“It is possible to mount a double suction centrifugal pump impeller with the vanes facing i ”相关问题

  • 第1题：

    单选题
    A double suction centrifugal pump impeller has been installed in the reverse direction, and will （）.
    A

    have a greater head capacity

    B

    operate with increased impeller efficiency

    C

    discharge through the suction side of the pump casing

    D

    require more power to run the shaft


    正确答案： A
    解析： 暂无解析

  • 第2题：

    单选题
    Pitting in the suction areas of a centrifugal pump bronze impeller is usually caused by （）.
    A

    cavitation

    B

    electrolysis

    C

    abrasion

    D

    corrosion


    正确答案： A
    解析： 暂无解析

  • 第3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 same

    B

    diameter of the suction piping, with all other factors remaining the same

    C

    width of the impeller only

    D

    diameter of the impeller


    正确答案： C
    解析： 暂无解析

  • 第4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 casing

    B

    absorb all impeller shaft end thrust

    C

    prevent water leakage to the atmosphere

    D

    prevent wear of the pump casing and/or impeller


    正确答案： D
    解析： 暂无解析

  • 第5题：

    单选题
    A centrifugal impeller consists of a number of vanes curving （） from the direction of rotation.
    A

    backwards

    B

    forwards

    C

    upward

    D

    downwards


    正确答案： B
    解析： 暂无解析

  • 第6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 speed

    B

    increase the size of the cardent assembly

    C

    reduce wearing ring clearances

    D

    change the pump to a close coupled arrangement


    正确答案： A
    解析： 暂无解析

  • 第7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 rings

    B

    bearings

    C

    easing volutes

    D

    wearing rings


    正确答案： D
    解析： 暂无解析

  • 第8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 overheated

    B

    enable a visual inspection of the pump while it is running

    C

    insure a proper alignment of the pump coupling to the driver

    D

    accommodate for friction between the impeller and the easing


    正确答案： C
    解析： 暂无解析

  • 第9题：

    单选题
    Most pump manufacturers recommend that the suction piping dimension for centrifugal pumps be （）.
    A

    one size smaller than the pump suction nozzle

    B

    the same size as the pump suction nozzle

    C

    one size larger than the pump suction nozzle

    D

    installed with a short radius elbow at the pump


    正确答案： B
    解析： 暂无解析

  • 第10题：

    单选题
    To maintain design discharge pressure from a centrifugal pump, the design clearance must be maintained between the （）.
    A

    shaft and impeller

    B

    motor and pump shaft

    C

    casing and impeller wearing rings

    D

    lantern ring and impeller


    正确答案： C
    解析： 暂无解析

  • 第11题：

    单选题
    The discharge head of a centrifugal pump will vary directly with the （）.
    A

    change in impeller diameter

    B

    square of the impeller diameter

    C

    cube of the impeller diameter

    D

    impeller efficiency for large changes in the size of the impeller


    正确答案： B
    解析： 暂无解析

  • 第12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 balances

    B

    weld counterweights to the light side of the impeller

    C

    remove metal from the heavy side by machining in a lathe

    D

    acid wash and serape the heavy side until it balances


    正确答案： D
    解析： 暂无解析

  • 第13题：

    单选题
    Reduced capacity, accompanied by vibration and noise at the suction of a centrifugal pump is a result of （）.
    A

    cavitation

    B

    water hammer

    C

    fluid friction

    D

    steam knock


    正确答案： A
    解析： 暂无解析

  • 第14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 same

    B

    diameter of the suction piping, with all other factors remaining the same

    C

    width of the impeller only

    D

    diameter of the impeller


    正确答案： B
    解析： 暂无解析

  • 第15题：

    单选题
    All of the following steps are taken in starting a centrifugal pump，EXCEPT to（）.
    A

    set the relief valve

    B

    check the lubrication system

    C

    vent the pump casing

    D

    open the pump suction and discharge valves


    正确答案： C
    解析： 暂无解析

  • 第16题：

    单选题
    The usual symptoms of cavitation in a centrifugal pump is （）.
    A

    noise and vibration

    B

    an increase in discharge pressure

    C

    an increase in suction pressure

    D

    lifting of the relief valve


    正确答案： B
    解析： 暂无解析

  • 第17题：

    单选题
    Attempts are made to eliminate axial thrust in centrifugal pump by （）.
    A

    providing the impeller with balancing holes

    B

    the use of symmetrical impeller

    C

    neither A nor B

    D

    either A or B


    正确答案： A
    解析： 暂无解析

  • 第18题：

    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 speed

    B

    excessive suction head

    C

    worn wearing rings

    D

    gross pump misalignment


    正确答案： D
    解析： 暂无解析

  • 第19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 improve

    B

    discharge to be reversed

    C

    efficiency to decrease

    D

    slippage to decrease


    正确答案： C
    解析： 暂无解析

  • 第20题：

    单选题
    In order to properly remove air from the casing of a centrifugal pump when starting, the pump should have a （）.
    A

    positive head

    B

    negative suction head

    C

    mechanical seal

    D

    vent valve attached to the casing at the top of the volute


    正确答案： D
    解析： 暂无解析

  • 第21题：

    单选题
    A centrifugal pump produces the required pressure energy by means of a rotating （） provided with vanes.
    A

    propeller

    B

    impeller

    C

    circumference

    D

    screw


    正确答案： A
    解析： 暂无解析

  • 第22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 casing

    B

    Low rotational speed of impeller

    C

    Removable end plate

    D

    Replaceable impeller and casing wearing rings


    正确答案： C
    解析： 暂无解析

  • 第23题：

    单选题
    The discharge rate or capacity of a centrifugal pump will vary directly as the （）.
    A

    change in the impeller diameter

    B

    square of the impeller radius

    C

    cube of the impeller diameter

    D

    impeller efficiency for large changes in its size


    正确答案： B
    解析： 暂无解析

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