bottom-blow valve
skin valve
feed-check valve
feed-stop valve
第1题：
A. It prevents the HTTP client or server from timing-out during an antivirus update
B. It prevents the HTTP client or server from timing-out during antivirus scanning.
C. It is an attack.
D. It is used to bypass antivirus scanners.
第2题：
What prevents water running along the shaft of a leaking centrifugal pump from entering the shaft bearing ________．
A.Shaft seal
B.Water flinger
C.Drain hole
D.Lantern ring
第3题：
A.water-tube
B.fire-tube
C.exhaust gas
D.composite
第4题：
low water level
high water level
excessively high fuel pressure
low oil temperature
第5题：
cradle
draft
harping
manger
第6题：
The boiler water alkalinity in a coil-type auxiliary boiler should be maintained at the pH recommended by the boiler manufacturer to______.
A.precipitate(使沉淀) silica （硅石）from solution
B.reduce corrosion in the heating coil
C.prevent clogging and erosion in the coil
D.maintain zero water hardness
第7题：
Which statement is correct about HTTP trickling?（）
第8题：
what chemicals did you use to treat the boiler water ?when you test alkalinity and acidity of water in boiler by pH test paper ? the result shows the boiler water is in acidiity . please describe what the possible cause is .
第9题：
Receives saturated steam from the generating tubes
Serves as a reservoir of boiler feed water
Holds internal fittings for separation of moisture from steam
Collects steam exhausted from the turbines
第10题：
natural circulation of the water in the water tube boiler is better than that in the fire tube boiler
for the same output the water tube boiler will carry less mass of water compared with the fire tube boiler
the water tube boiler will cost shorter time for steam raising
the water tube boiler require lower skill in operating and maintaining