A.acid
B.alkali
C.salt
D.None of the above
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A.proper combustion
B.water in the fuel
C.excess air
D.cold fuel oil
A.The safety valve escape piping should be disconnected from the valve body and a blank inserted
B.The boiler vent valves should be opened
C.All hand-hole/manhole covers should be tightened up as much as possible to preclude any leaks
D.All of the above
A.The boiler oil tank
B.The steam pipe
C.The fire side
D.The safety valves
A.oxygen in the water
B.poor boiler design
C.density too high
D.excessive steam demand
A.yellowish flame
B.golden yellow flame
C.white flame
D.brilliant white flame
最新試題
Heavy wear in a particular area of the inner circumference of a packing ring may be caused by （）.
The control mode in which the final control element is moved from one of two flexed positions to the other is known as （）.
Who is responsible for ensuring that someone is assigned to close the watertight doors in an emergency?（）
An increasing head pressure in a refrigeration system, without any corresponding change in the cooling water inlet temperature, would probably be caused by （）.
If the head pressure of a reciprocating refrigeration compressor is excessive, （）.
Low compressor head pressure in a refrigeration system can be caused by（）.
The output volume of a positive fixed displacement pump can be changed only by （）.
Thermostatic expansion valves can be adjusted for （）.
Which of the listed pumps is NOT a positive displacement pump?（）
Which of the following problems could cause the high pressure cutout switch to shut down the compressor in a refrigeration system?（）