A.two or more impellers housed together in one casing and mounted on a single shaft
B.a single stepped impeller mounted in a progressively staged casing
C.a large radial clearance between the impeller and casing to prevent overheating due to
D.an increase in the discharge velocity of the liquid with a corresponding decrease in pressure through the stages
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A.add refrigerant to the system
B.adjust the thermal expansion valve to the proper setting
C.adjust the float valve to the proper holding pressure
D.open the hand expansion valve
A.a stuck solenoid valve
B.a shortage of refrigerant
C.too much oil in circulation
D.too much superheat
A.trick-wheel
B.follow-up control
C.six-way valve
D.Rapson slide
A.stress
B.strain
C.shear strength
D.ultimate tensile strength
A.increase discharge pressure
B.decrease pump capacity
C.decrease pump cavitation
D.decrease reaction ring clearance
最新試題
Which of the following problems could cause the high pressure cutout switch to shut down the compressor in a refrigeration system?（）
If the head pressure of a reciprocating refrigeration compressor is excessive, （）.
The amount of fluid friction or internal friction inherent in a mineral lubricating oil is reflected as a measure of its （）.
The major source of chemical contaminants in hydraulic fluid is （）.
The control mode in which the final control element is moved from one of two flexed positions to the other is known as （）.
Which of the listed pumps is NOT a positive displacement pump?（）
A salinity indicator is used to determine the （）.
A gradual decrease in the discharge pressure of an operating hydraulic pump can be caused by （）.
Heavy wear in a particular area of the inner circumference of a packing ring may be caused by （）.
Which of the following statements is correct concerning heat transfer?（）