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
Which of the listed pumps is NOT a positive displacement pump?（）
If the head pressure of a reciprocating refrigeration compressor is excessive, （）.
Thermostatic expansion valves can be adjusted for （）.
When a refrigeration compressor has developed a high head pressure as a result of a refrigerant overcharge, you should （）.
The general purpose of a heat exchanger is to （）.
The usual symptoms of cavitation in a centrifugal pump is （）.
If the relief valve on the discharge side of a hydraulic pump lifts, the cause could be （）.
When the steering gear is in operation, you should （）.
The output volume of a positive fixed displacement pump can be changed only by （）.
One cause of high head pressure occurring in a refrigeration system can be （）.