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
A gradual decrease in the discharge pressure of an operating hydraulic pump can be caused by （）.
The control mode in which the final control element is moved from one of two flexed positions to the other is known as （）.
Thermostatic expansion valves can be adjusted for （）.
If the thermal bulb of an expansion valve is incorrectly placed at the center of the coil instead of the end, it will （）.
On tank vessels equipped with power operated cargo tank valves, the type of power operator most commonly used is （）.
An internal bypass is provided on some hydraulic system suction strainers to help reduce the possibility of （）.
An increasing head pressure in a refrigeration system, without any corresponding change in the cooling water inlet temperature, would probably be caused by （）.
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 （）.
A pressure drop through the refrigerant liquid line may cause （）.
The general purpose of a heat exchanger is to （）.