A.CO2
B.Methyl chloride
C.R-22
D.Sulphur dioxide
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A.Suction head
B.Pump head
C.Discharge head
D.Total head
A.toxic
B.flammable
C.explosive
D.all of the above
A.Fire pump and lube oil pump
B.Lube oil pump and distilling plant
C.Distilling plant and shaft alley door
D.Shaft alley door and fixed CO2 release
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
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
最新試題
Pitting in the suction areas of a centrifugal pump bronze impeller is usually caused by （）.
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 problems listed would came the discharge temperature of an R-12 refrigeration compressor to increase?（）
One cause of high head pressure occurring in a refrigeration system can be （）.
The rate of heat transfer between the hot and cold fluids passing through a shell-and-tube type heat exchanger will （）.
The rate of heat transfer from a hot region to a cold region is affected most by the （）.
The control mode in which the final control element is moved from one of two flexed positions to the other is known as （）.
Who is responsible for ensuring that someone is assigned to close the watertight doors in an emergency?（）
The usual symptoms of cavitation in a centrifugal pump is （）.
A gradual decrease in the discharge pressure of an operating hydraulic pump can be caused by （）.