A.superheated outside the system
B.in contact with an open flame
C.heated to the boiling point
D.All of the above
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A.Variable volumes can be obtained with gear pumps only by variation of the pump drive speed
B.A radial piston pump houses sliding pistons in a stationary cylinder block through which passes a rotating pintle or ported shaft
C.The amount of fluid displaced per revolution of an axial piston rotary pump is dependent on the angle formed between the cylinder block and valve plate
D.All of the above
A.transmit the rudder angle to the bridge indicator
B.prevent the control linkage from striking the stops when hard over
C.automatically purge all entrained air from the system
D.send hydraulic signals to the receiving unit
A.horizontally mounted
B.never fitted with intake filters
C.fitted with intercoolers
D.operated in an unloaded condition at all times
A.High pressure compressors are more efficient than low pressure compressors
B.Mechanical efficiency divided by compressor efficiency will equal the overall efficiency of the compressor unit
C.Two stage compressors are generally more efficient than single stage compressors
D.The volumetric efficiency is decreased in multistage compressors
A.precipitation number
B.neutralization number
C.pour point
D.demulsibility
最新試題
An increasing head pressure in a refrigeration system, without any corresponding change in the cooling water inlet temperature, would probably be caused by （）.
The amount of fluid friction or internal friction inherent in a mineral lubricating oil is reflected as a measure of its （）.
Pitting in the suction areas of a centrifugal pump bronze impeller is usually caused by （）.
One cause of high head pressure occurring in a refrigeration system can be （）.
The temperature differential occurring between the inlet temperature of the fluid to be cooled and the outlet temperature of the cooling medium in a shell-and-tube heat exchanger is greatest in which of the flow designs listed?（）
A pressure drop through the refrigerant liquid line may cause （）.
A salinity indicator is used to determine the （）.
If the thermal bulb of an expansion valve is incorrectly placed at the center of the coil instead of the end, it will （）.
Which of the following statements is correct concerning heat transfer?（）
An internal bypass is provided on some hydraulic system suction strainers to help reduce the possibility of （）.