A.Absorb erosion of high velocity discharge stream
B.Seal pump shaft against entry of air
C.Isolate the discharge side from the suction side
D.Dampen the turbulent discharge flow
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A.cooling only
B.cooling and humidifying
C.cooling and dehumidifying
D.adiabatic cooling
A.Sea water is heated to boiling temperature while under a vacuum
B.Sea water is passed over heated plates in a thin film
C.Heated sea water is injected into a vacuum chamber
D.Sea water is forced through a heated eductor
A.Vapor pockets formed in the suction flow stream
B.Rough easing volute surfaces
C.Worn wearing rings
D.Heavy fluid in the flow stream
A.primarily to lubricate the shaft seals
B.due to the inability of this type of pump to lift water to cover the suction (eye) of the impeller
C.to initially unload the pump by having its head pressure equal to discharge pressure
D.in order to overcome the potential energy of water in the discharge line
A.humidification
B.dehumidification
C.vaporization
D.evaporation
最新試題
Which of the problems listed would came the discharge temperature of an R-12 refrigeration compressor to increase?（）
A salinity indicator is used to determine the （）.
An internal bypass is provided on some hydraulic system suction strainers to help reduce the possibility of （）.
When a refrigeration compressor has developed a high head pressure as a result of a refrigerant overcharge, you should （）.
One cause of high head pressure occurring in a refrigeration system can be （）.
A salinity indicator is used to determine the （）.
The output volume of a positive fixed displacement pump can be changed only by （）.
The major source of chemical contaminants in hydraulic fluid is （）.
If the viscosity of the liquid being transferred remains constant as the discharge pressure increases, the rotary pump （）.
An excessive charge of refrigerant in an air-cooled refrigeration system can cause （）.