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
An excessive charge of refrigerant in an air-cooled refrigeration system can cause （）.
If the thermal bulb of an expansion valve is incorrectly placed at the center of the coil instead of the end, it will （）.
An internal bypass is provided on some hydraulic system suction strainers to help reduce the possibility of （）.
The output volume of a positive fixed displacement pump can be changed only by （）.
A salinity indicator is used to determine the （）.
Which of the listed pumps is NOT a positive displacement pump?（）
The rate of heat transfer between the hot and cold fluids passing through a shell-and-tube type heat exchanger will （）.
Pitting in the suction areas of a centrifugal pump bronze impeller is usually caused by （）.
When a refrigeration compressor has developed a high head pressure as a result of a refrigerant overcharge, you should （）.
Who is responsible for ensuring that someone is assigned to close the watertight doors in an emergency?（）