A.condensate
B.a small amount of make-up feed
C.A and B
D.None of the above
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A.yellowish flame
B.golden yellow flame
C.white flame
D.brilliant white flame
A.low water level
B.low oil pressure
C.excessively high fuel pressure
D.an improper air/fuel ratio
A.Reciprocating pump
B.Screw pump
C.Diffuser pump
D.Water-ring pump
A.discharge is continuous
B.it has no internal valves
C.upon accidental closing of discharge valve, excessive pressure will not build up
D.all of the above are true
A.between the suction and discharge
B.below the liquid supply
C.above the liquid supply
D.any of the above
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 （）.
Which of the following statements is correct concerning heat transfer?（）
The temperature differential occurring between the inlet temperature of the fluid to be cooled and the outlet temperature of the cooling medium in a shell-and-tube heat exchanger is greatest in which of the flow designs listed?（）
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 rate of heat transfer from a hot region to a cold region is affected most by the （）.
Heavy wear in a particular area of the inner circumference of a packing ring may be caused by （）.
Which of the problems listed would came the discharge temperature of an R-12 refrigeration compressor to increase?（）
Which of the listed pumps is NOT a positive displacement pump?（）
Low compressor head pressure in a refrigeration system can be caused by（）.