A.Reduction of friction
B.Insulation of hot surfaces
C.Lubrication of moving parts
D.Elevation of cooler outlet temperatures
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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
A.pump must always be primed
B.volute must impart a radial and rotary motion of the water suction side
C.connection must guide the liquid to the lantern rings
D.stuffing box should not be allowed any water leakage
A.change in impeller diameter
B.square of the impeller diameter
C.cube of the impeller diameter
D.impeller efficiency for large changes in the size of the impeller
A.the suction pressure to decrease
B.the suction temperature to increase
C.increased ice formation on the evaporator coil
D.excessive short cycling of the compressor
最新試題
The amount of fluid friction or internal friction inherent in a mineral lubricating oil is reflected as a measure of its （）.
The control mode in which the final control element is moved from one of two flexed positions to the other is known as （）.
If the head pressure of a reciprocating refrigeration compressor is excessive, （）.
A salinity indicator is used to determine the （）.
A pressure drop through the refrigerant liquid line may cause （）.
When a refrigeration compressor has developed a high head pressure as a result of a refrigerant overcharge, you should （）.
A salinity indicator is used to determine the （）.
Which of the following statements is correct concerning heat transfer?（）
Thermostatic expansion valves can be adjusted for （）.
When the steering gear is in operation, you should （）.