An increase in rotor clearances in a rotary pump will ______.A.increase discharge pressureB.decrease pump capacityC.decrease pump cavitationD.decrease reaction ring clearance
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
相关考题：
Which of the following terms is used to identify the pressure of the liquid entering a pump?A.Suction headB.Pump headC.Discharge headD.Total head
Which statement is NOT true?A.While displacement pump works, volume of the working chamber will increase and decrease alternatelyB.A gear pump always has two gearsC.Any vane pump will have a rotor within a ringD.A balanced vane pump has two outlet ports and they are positioned symmetrically
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
Which statement is NOT true?A.In a simple vane pump, the rotor and cam ring are exactly concentricB.Balanced vane pump has an elliptical cam ringC.Liquid in both gear pump and vane pump are forced out to the outlet.D.Balanced vane pumps can work at a higher pressure than the simple vane pump
An increase in the fuel injection pump discharge pressure can be caused by a/an _______.A.leaking delivery valveB.excessive bearing end playC.plugged injector spray holeD.increased plunger stroke
The pressure of a liquid leaving the pump can be referred to as the ______.A.total headB.discharge headC.net positive suction headD.suction head
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
Which method should be used to warm up the pump turbines prior to discharge ________．A.Lock the turbine rotor and slowly bleed in steam until operating temperature is reachedB.Run the pump at high speed with the discharge valves closedC.Run the turbine at slow speed with the pump disconnectedD.Shut the discharge valve and run the pump at slow speed
单选题In （） pump a closed discharge valve will not cause excessive pressure to build up.AgearBvaneCscrewDcentrifugal
单选题A multistage centrifugal pump can be BEST described as having （）.Atwo or more impellers housed together in one casing and mounted on a single shaftBa single stepped impeller mounted in a progressively staged casingCa large radial clearance between the impeller and casing to prevent overheating due toDan increase in the discharge velocity of the liquid with a corresponding decrease in pressure through the stages
单选题A centrifugal bilge pump requires priming （）.Aprimarily to lubricate the shaft sealsBdue to the inability of this type of pump to lift water to cover the suction (eye) of the impellerCto initially unload the pump by having its head pressure equal to discharge pressureDin order to overcome the potential energy of water in the discharge line
单选题Which of the following statements represents the advantage of rotary pumps as compared to reciprocating pumps?（）AThe high discharge pressure of the rotary pumps permits a larger volume of fluid per unit time than the reciprocating pumpBRotary pumps are capable of pumping more fluid than reciprocating pumps of the same weightCRotary pumps occupy only one-half the space of reciprocating pumpsDRotary pumps eliminate discharge slippage of the pumped liquid, while this does not hold true for a reciprocating pump
单选题If a hydraulic pump is overheating, the cause may be （）.Aexcessive internal leakage in the pumpBlow discharge pressure and fluid flowCexcessive fluid level in the hydraulic reservoirDoperation of the pump at 100% efficiency
单选题Which of the following will be the advantage of a centrifugal pump as compared with a reciprocating pump?（） (1) Its discharge is continuous (2) It has no internal valves (3) Upon accidental closing of discharge valve, excessive pressure will not build upA（1），（2）B（2），（3）C（1），（2），（3）D（2）only
单选题Which method should be used to warm up the pump turbines prior to discharge（）.ALock the turbine rotor and slowly bleed in steam until operating temperature is reachedBRun the pump at high speed with the discharge valves closedCRun the turbine at slow speed with the pump disconnectedDShut the discharge valve and run the pump at slow speed
单选题If the viscosity of the liquid being transferred remains constant as the discharge pressure increases, the rotary pump （）.Acapacity will increaseBcapacity will decreaseCsuction pressure will increaseDsuction pressure will decrease
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 （）.Adiameter of the discharge piping, with all other factors remaining the sameBdiameter of the suction piping, with all other factors remaining the sameCwidth of the impeller onlyDdiameter of the impeller
单选题The usual symptoms of cavitation in a centrifugal pump is （）.Anoise and vibrationBan increase in discharge pressureCan increase in suction pressureDlifting of the relief valve
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（）.Aexcessive pump speedBexcessive suction headCworn wearing ringsDgross pump misalignment
单选题Operating a rotary pump at speeds in excess of design requirements could cause（）.Adecreased clearances between rotating partsBdecreased slippage to the suction side of the pumpCair binding in the discharge portsDerosion and excessive wear
单选题If a bilge pump failed to build up discharge pressure, you should check for （）.Aexcessive water in the bilgesBa clogged suction strainerCoil in the bilgesDAll of the above
单选题To maintain design discharge pressure from a centrifugal pump, the design clearance must be maintained between the （）.Ashaft and impellerBmotor and pump shaftCcasing and impeller wearing ringsDlantern ring and impeller
单选题The （） discharge a nearly constant amount of liquid regardless of pressure.Amixed-flow pumpBaxial-flow pumpCcentrifugal pumpDdisplacement pump
单选题The pump discharge pressure will be considerably higher than the pressure at the （）.Apump entry branchBoutlet pipeCimpellerDNone of the above is true
单选题The boiler feed pump discharge pressure is higher than the steam drum pressure to （）.Aensure feed water flow into the boilerBkeep the steam drum pressure highCprevent water hammer in the feed lineDhelp the feed water flash to steam
单选题An increase in rotor clearances in a rotary pump will （）.Aincrease discharge pressureBdecrease pump capacityCdecrease pump cavitationDdecrease reaction ring clearance
单选题An increase in the fuel injection pump discharge pressure can be caused by a/an （）Aleaking delivery valveBexcessive bearing end playCplugged injector spray holeDincreased plunger stroke