A.flooding back
B.superheating
C.overflowing
D.recycling
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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
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
最新試題
A salinity indicator is used to determine the （）.
The general purpose of a heat exchanger is to （）.
Which of the listed pumps is NOT a positive displacement pump?（）
When a refrigeration compressor has developed a high head pressure as a result of a refrigerant overcharge, you should （）.
The output volume of a positive fixed displacement pump can be changed only by （）.
Which of the following problems could cause the high pressure cutout switch to shut down the compressor in a refrigeration system?（）
One cause of high head pressure occurring in a refrigeration system can be （）.
The rate of heat transfer from a hot region to a cold region is affected most by the （）.
Which of the following statements is correct concerning heat transfer?（）
Heavy wear in a particular area of the inner circumference of a packing ring may be caused by （）.