A.oxygen in the water
B.poor boiler design
C.density too high
D.excessive steam demand
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A.yellowish flame
B.golden yellow flame
C.white flame
D.brilliant white flame
A.condensate
B.a small amount of make-up feed
C.A and B
D.None of the above
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
最新試題
The control mode in which the final control element is moved from one of two flexed positions to the other is known as （）.
An internal bypass is provided on some hydraulic system suction strainers to help reduce the possibility of （）.
Thermostatic expansion valves can be adjusted for （）.
The rate of heat transfer from a hot region to a cold region is affected most by the （）.
The rate of heat transfer between the hot and cold fluids passing through a shell-and-tube type heat exchanger will （）.
Pitting in the suction areas of a centrifugal pump bronze impeller is usually caused by （）.
An excessive charge of refrigerant in an air-cooled refrigeration system can cause （）.
Which of the problems listed would came the discharge temperature of an R-12 refrigeration compressor to increase?（）
Low compressor head pressure in a refrigeration system can be caused by（）.
An increasing head pressure in a refrigeration system, without any corresponding change in the cooling water inlet temperature, would probably be caused by （）.