positive displacement
ejector
centrifugal
air compressor
第1题：
Which statement is NOT true?
A.In a simple vane pump, the rotor and cam ring are exactly concentric
B.Balanced vane pump has an elliptical cam ring
C.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
第2题：
conduction
radiation
convection
advection
第3题：
Which of the following terms is used to identify the pressure of the liquid entering a pump?
A.Suction head
B.Pump head
C.Discharge head
D.Total head
第4题：
two or more impellers housed together in one casing and mounted on a single shaft
a single stepped impeller mounted in a progressively staged casing
a large radial clearance between the impeller and casing to prevent overheating due to
an increase in the discharge velocity of the liquid with a corresponding decrease in pressure through the stages
第5题：
kinetic；pressure
kinetic；essential
pressure；kinetic
pressure；height
第6题：
draw the liquid in；force the liquid out
force the liquid out；draw the liquid in
suction；draw
deliver；outlet
第7题：
Oil is discharged from the impeller through the outlet
Gravity causes the oil to flow toward the discharge
The self-priming feature of the centrifugal pump enables it to draw its own suction as it starts
The discharge capacity varies directly with the speed of the impeller
第8题：
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 impeller
B.from passage of impeller
C.from the periphery of the impeller
D.from the impeller
第9题：
reduce radial thrust to the impeller
double the liquid velocity through the pump when compared to a single volute
reduce hydraulic end thrust
provide the effect of multi-staging
第10题：
In order for a fluid to be pumped, a fluid must be made to flow
A substance must be cold in order for it to be pumped
The kinetic energy imparted by the pump can be used to force a liquid through a hydraulic system
A pump must receive its energy from an external source