单项选择题
Fins are installed on the fireside of water-tubes used in waste boiler to（）
A.decrease the velocity of gases flowing past the tubes B.increase the rate of heat transfer C.reduce accumulations carbon deposits D.direct the flow of gases
单项选择题 A smoking burner with a pulsating flame in auxiliary boiler, is an indication that the（）
单项选择题 The correct procedure for giving an auxiliary boiler a bottom blow, is to begin（）
单项选择题 Bottom blow valves are installed on auxiliary water-tube boilers to （）
