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
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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
A.liquid strainer
B.refrigerant inlet of the condenser
C.inlet side of the evaporator
D.suction side of the compressor
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One cause of high head pressure occurring in a refrigeration system can be （）.
When a refrigeration compressor has developed a high head pressure as a result of a refrigerant overcharge, you should （）.
An excessive charge of refrigerant in an air-cooled refrigeration system can cause （）.
The amount of fluid friction or internal friction inherent in a mineral lubricating oil is reflected as a measure of its （）.
On tank vessels equipped with power operated cargo tank valves, the type of power operator most commonly used is （）.
An internal bypass is provided on some hydraulic system suction strainers to help reduce the possibility of （）.
Which of the listed pumps is NOT a positive displacement pump?（）
Which of the problems listed would came the discharge temperature of an R-12 refrigeration compressor to increase?（）
The rate of heat transfer from a hot region to a cold region is affected most by the （）.
A pressure drop through the refrigerant liquid line may cause （）.