更多"When starting a centrifugal pump, t"的相关试题:
[单项选择]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
[单项选择]When starting a reciprocating pump, the inlet valve should be （）.
A. closed
B. opened fully
C. cracked open
D. partly open
[单项选择]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
[单项选择]The opening or closing of the cylinder starting valve is controlled by （）.
A. the starting air distributor
B. the cut-off valve on the air main
C. the main starting valve
D. the air bottle control valve
[单项选择]Pump up the starting air reservoirs to their maximum pressure and （）the air reservoirs and air system.
A. open
B. close
C. drain
D. vent
[单项选择]Before starting a reciprocating, steam-driven pump that has been idle for a period of time, you should （）.
A. open the steam line mot valve
B. drain the steam cylinder
C. close the steam cylinder drains
D. open the liquid cylinder drains
[单项选择]When disassembling or assembling an injection pump plunger and barrel you should （）
A. keep the parts immersed in diesel fuel
B. always keep the plunger and barrel together
C. work over a linoleum-type surface
D. all of the above
[单项选择]The starting air entering the cylinder begins when the piston（）
A. has nearly come to the TDC
B. has just past the TDC
C. has nearly come to the BDC
D. has just past the BDC
[单项选择]When start a screw pump, the by pass valve should be （）.
A. closed
B. opened fully
C. cracked open
D. partly open
[单项选择]
When a hydraulic vane pump is working, which of the following is in contact with the vanes?（）
(1) the rotor
(2) the internal surface of the housing
(3) the external surface of the housing
A. (1) only
B. (2) only
C. (1) and (2)
D. (1), (2) and (3)
[单项选择]A centrifugal pump may fail to deliver water when first started if the （）.
A. water seal pipe is plugged
B. pump is not primed
C. seal ring is improperly located
D. impeller is flooded
[单项选择]When starting an engine, the compressed air enters the cylinder when the corresponding piston is in position of its（）
A. suction stroke
B. compression stroke
C. power stroke
D. exhaust stroke
[单项选择]When the starting air valve closes on one cylinder, another starting air valve has （） opened on another cylinder whose piston has just commenced its downward stroke.
A. just
B. nearly
C. merely
D. already
[单项选择]If a centrifugal pump vibrates and is noisy when operating, the cause could be （）.
A. worn gland sealing shaft
B. worn wearing rings
C. a bent shaft
D. reversed pump coupling
[单项选择]When starting air is admitted, a diesel engine turns over very slowly without firingThe cause may be （）
A. an obstruction in an cylinder
B. water accumulation in some engine cylinders
C. low starting air pressure
D. low scavenge air pressure
[单项选择]When starting CPR on a drowning victim，you should（）.
A. start chest compressions before the victim is removed from the water
B. drain water from the lungs before ventilating
C. begin mouth-to-mouth ventilations as soon as possible
D. do not tilt the head back since it may cause vomiting
[单项选择]
When starting air-conditioner in the winter, we should open（）in sequence.
Ⅰ.alve of warming
Ⅱ.alve of humidifier
Ⅲ.an
A. Ⅲ-Ⅱ-Ⅰ
B. Ⅲ-Ⅰ-Ⅱ
C. Ⅰ-Ⅲ-Ⅱ
D. Ⅱ-Ⅲ-Ⅰ
[单项选择]When an engine is starting and has got a sufficiently high speed, say about 20 rpm,（）
A. the starting air supply is cut off and fuel is injected into the cylinders
B. the fuel feeding is cut off and the turning gear is put in
C. the starting air supply is cut off and turning gear is taken out
D. the electric blower is shut down and fuel is injected into the cylinders
