A.oxygen in the water
B.poor boiler design
C.density too high
D.excessive steam demand
您可能感興趣的試卷
你可能感興趣的試題
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
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 （）.
An internal bypass is provided on some hydraulic system suction strainers to help reduce the possibility of （）.
The usual symptoms of cavitation in a centrifugal pump is （）.
A pressure drop through the refrigerant liquid line may cause （）.
Thermostatic expansion valves can be adjusted for （）.
A gradual decrease in the discharge pressure of an operating hydraulic pump can be caused by （）.
An excessive charge of refrigerant in an air-cooled refrigeration system can cause （）.
Which of the following problems could cause the high pressure cutout switch to shut down the compressor in a refrigeration system?（）
The rate of heat transfer between the hot and cold fluids passing through a shell-and-tube type heat exchanger will （）.
The control mode in which the final control element is moved from one of two flexed positions to the other is known as （）.