超星 - Chapter_3_Pumps - 查题吧

单选题

The commonly used pressure of the pump includes: a. the output pressure of the pump; b. maximum pressure of pump; c. rated pressure of pump. The relationship of the above three pressures should be ().

A. b>a>c
B. b>c>a
C. a>c>b
D. c>a>b

单选题

The flow rate of pump at rated speed and rated pressure is called ().

A. actual flow
B. theoretical flow
C. rated flow

单选题

In the case of no leakage, the flow calculated from the pump is called ().

A. actual flow
B. theoretical flow
C. rated flow

单选题

In practice, when the pump pressure is zero,the flow rate of itis often regarded as ().

A. actual flow
B. theoretical flow
C. rated flow
D. leakage flow

单选题

The input power to hydraulic pump should be greater than the output power of the hydraulic pump, because of ().

A. leakage loss;
B. friction loss;
C. overflow loss;
D. both leakge loss and friction loss

单选题

Which type of hydraulic pump can be used as a variable displacement pump? ()

A. gear pump
B. single acting vane pump
C. double acting vane pump
D. B + C

单选题

Variable displacement pumps used in hydraulic applications can1. have variable flow rate2. consume less energy3. be operated with high accuracy for slow and rapid motion 4. generate more heat

A. 1 and 2
B. 3 and 4
C. 1, 2 and 3
D. all the above

单选题

Electric motor has a speed of 1200 rpm and output rate of pump is 6 mL/rev. Calculate flow rate of pump in l/min

A. 6 l/min
B. 7.2 l/min
C. 5 l/min
D. none of the above

单选题

Calculate the power absorbed by the pump if, it has a flow rate of 20 mL/rev and develops a maximum pressure of 70 bar, when electric motor runs at a speed of 1200 rpm.

A. 1.9 kW
B. 2.8 kW
C. 2.3 kW
D. none of the above

单选题

Volumetric efficiency of the pump is the ratio of

A. theoretical flow rate to actual flow rate
B. actual flow rate to theoretical flow rate
C. actual fluid power to pump input power
D. none of the above

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