单项选择题
A.The blow down valve B.The scum valve C.The air release cock D.The soot-blower
In motor ship, （） is often used to recover some of the ...
单项选择题In motor ship, （） is often used to recover some of the heat carried in the exhaust gases from the main engine.
A.an diesel oil heater B.a waste heat boiler C.a fresh water generator D.all the above
Impurities from the boiler water surface can be removed...
单项选择题Impurities from the boiler water surface can be removed through the （）.
A.safety valve B.blow down valve C.scum valve D.feed check valve
You should frequently compare drum-mounted and remote-r...
单项选择题You should frequently compare drum-mounted and remote-reading water level indicators（） between these have contributed to failures because of overheating through shortage of water, when a boiler was being oil-fired.
A.descriptions B.discrepancies C.different D.deflections
