A.either all the way open or all the way closed
B.normally open
C.throttled depending on load
D.controlled by suction pressure
您可能感興趣的試卷
你可能感興趣的試題
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)
A.Control of evaporation
B.A separate means to prevent feed-water contamination
C.Power circulating pump
D.Super-heater
A.check and regulate the water level
B.close the air cock once fires are lit
C.blowdown the gage glass
D.crack the steam stop to assure protective steam flow
A.furnace to be re-purged
B.electric charge to buildup in the igniter
C.fuel pump to restart
D.drum level to stabilize
A.The blow down valve
B.The scum valve
C.The air release cock
D.Scot-blower
最新試題
If the thermal bulb of an expansion valve is incorrectly placed at the center of the coil instead of the end, it will （）.
Pitting in the suction areas of a centrifugal pump bronze impeller is usually caused by （）.
Thermostatic expansion valves can be adjusted for （）.
The amount of fluid friction or internal friction inherent in a mineral lubricating oil is reflected as a measure of its （）.
When the steering gear is in operation, you should （）.
Heavy wear in a particular area of the inner circumference of a packing ring may be caused by （）.
If the relief valve on the discharge side of a hydraulic pump lifts, the cause could be （）.
If you are given the job of adding hydraulic fluid to a mooring winch, and are not certain as to the type of fluid to use, you should （）.
An increasing head pressure in a refrigeration system, without any corresponding change in the cooling water inlet temperature, would probably be caused by （）.
Which of the listed pumps is NOT a positive displacement pump?（）