A.bypass the high pressure stage to the low pressure stage on 100% of the air compressors in service
B.prevent excessive inter-stage pressure buildup
C.control compressor discharge pressure
D.remove all but the frictional load during starting
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A.The relief valves in the system should be readjusted
B.The filters and strainers should be checked frequently
C.All system pressure should be readjusted
D.The system should be drained and renewed with a fluid of different operating characteristics
A.100℃
B.125℃
C.150℃
D.175℃
A.maintain radial alignment between the pump impeller and casing
B.absorb all impeller shaft end thrust
C.prevent water leakage to the atmosphere
D.prevent wear of the pump casing and/or impeller
A.psychrometer
B.salinometer
C.anemometer
D.sphygmomanometer
A.A large change of viscosity occurs with a minor change in temperature
B.No change in viscosity occurs with any change in temperature
C.Very little change in viscosity occurs with a significant change in temperature
D.The viscosity of the oil increases with an increase in temperature
最新試題
The major source of chemical contaminants in hydraulic fluid is （）.
An excessive charge of refrigerant in an air-cooled refrigeration system can cause （）.
Who is responsible for ensuring that someone is assigned to close the watertight doors in an emergency?（）
An increasing head pressure in a refrigeration system, without any corresponding change in the cooling water inlet temperature, would probably be caused by （）.
When a refrigeration compressor has developed a high head pressure as a result of a refrigerant overcharge, you should （）.
Low compressor head pressure in a refrigeration system can be caused by（）.
The general purpose of a heat exchanger is to （）.
If the relief valve on the discharge side of a hydraulic pump lifts, the cause could 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?（）
On tank vessels equipped with power operated cargo tank valves, the type of power operator most commonly used is （）.