更多"Centrifugal pumps are non-positive "的相关试题:
[单项选择]Centrifugal pumps are popular because they are very simple in construction,and produce smooth, constant, （） discharge.
A. non-pulsating
B. pulsating
C. positive
D. non-positive
[单项选择]Under centrifugal pumps are the volute, diffuser, mixed-flow, axial flow and （） or regenerative types.
A. reciprocating
B. hydraulic
C. turbine
D. vane
[单项选择]Centrifugal pumps can be designed with a number of impellers （） to attain a high final delivery pressure.
A. in series
B. in parallel
C. either A or B
D. None of the above is tree
[单项选择]Centrifugal pumps have what advantage(s) over reciprocating pumps?（）.
A. They are less expensive
B. They are smaller for equivalent pumping ability
C. They pump more cargo in less time
D. All of the above
[单项选择]Centrifugal pumps, however, can be designed with a number of impellers （） to attain a large amount of liquid.
A. in series
B. in parallel
C. assembled
D. together
[单项选择]Gear pumps are of positive displacement type pumps because they discharge a near constant amount of liquid （） pressure.
A. depending on
B. in relative to
C. regardless of
D. because of
[单项选择]Which of the following centrifugal pump components converts the liquid kinetic energy of velocity to the potential energy of pressure?（）
A. Impeller
B. Electric motor
C. Volute
D. Eye
[单项选择]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
[单项选择]Why are removable sleeves installed on centrifugal pump shafts?（）
A. They make it easier to replace the pump shaft packing
B. They can be economically replaced as they wear out
C. They can be removed when it is necessary to lighten the weight of the pump
D. They increase the strength of the shaft
[单项选择]The centrifugal pump component responsible for converting the mechanical energy of the liquid being pumped, to that of kinetic energy is the （）.
A. electric motor
B. volute
C. impeller
D. diffusion nozzle
[单项选择]A centrifugal pump produces the required pressure energy by means of a rotating （） provided with vanes.
A. propeller
B. impeller
C. circumference
D. screw
[单项选择]A centrifugal pump attempting to develop flow against a closed discharge valve has a/an （）.
A. capacity of 0%
B. efficiency of 100%
C. internal slippage of 0%
D. shut off horsepower rating of 100%
[单项选择]If you were operating a centrifugal water service pump with worn wearing rings, the （）.
A. pump would be very noisy
B. pump would vibrate excessively
C. pump would develop insufficient flow
D. stuffing box would leak excessively
[单项选择]If a centrifugal bilge pump were continually operated with the discharge valve closed the （）.
A. motor overload would open
B. relief valve would open
C. pump would eventually overheat
D. motor would overheat
[单项选择]If a centrifugal pump were continually operated with the discharge valve closed, the （）.
A. motor controller overload would open
B. pump would eventually overheat
C. relief valve would continuously cycle open
D. motor would overheat
[单项选择]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
[单项选择]A spring-loaded centrifugal flyweight governor responds to reduced engine load with an immediate increase in （）
A. pilot valve oil pressure
B. speeder spring force
C. compensation needle valve clearance
D. centrifugal force on the flyweights
[单项选择]What is a characteristic of all centrifugal cargo pumps? （）
A. They are self-priming
B. Decreasing the speed of rotation will decrease the discharge pressure
C. Opening the discharge valve wider will increase the discharge pressure
D. All of the above
[单项选择]For optimum results, centrifugal purification of heavy fuel oil should be accomplished with the fuel at the lowest practicable（）
A. throughput
B. additive percent
C. cetane number
D. TBN number
