A.has continuously for a long period
B.suction pressure is below normal
C.oil level is below normal
D.starts after a long idle period
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A.protect the pump from fine soluble contaminants
B.prevent solid particles from entering the pump
C.prevent solid particles from entering the filter
D.protect the directional control valves
A.Feed-water heater internal tube surfaces
B.Internal distillate cooler tubes
C.Flash chamber vertical surfaces
D.Distilling condenser tubes
A.Reduction of friction
B.Insulation of hot surfaces
C.Lubrication of moving parts
D.Elevation of cooler outlet temperatures
A.higher boiling temperature for a given pressure than does a pure refrigerant
B.lower boiling temperature for a given pressure than does a pure refrigerant
C.boiling pressure equal to that of a pure refrigerant at a given pressure
D.boiling point will not be affected by entrained oil
A.Degree of saturation
B.Saturation temperature
C.Superheated temperature
D.Degree of superheat
最新試題
When a refrigeration compressor has developed a high head pressure as a result of a refrigerant overcharge, 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 （）.
When the steering gear is in operation, you should （）.
The output volume of a positive fixed displacement pump can be changed only by （）.
One cause of high head pressure occurring in a refrigeration system can be （）.
A salinity indicator is used to determine the （）.
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?（）
Who is responsible for ensuring that someone is assigned to close the watertight doors in an emergency?（）
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 internal bypass is provided on some hydraulic system suction strainers to help reduce the possibility of （）.