单项选择题
A.Boiler B.Incinerator C.Oily water separator D.Sewage treatment unit
High-speed rotation in a centrifugal purifier can produ...
单项选择题High-speed rotation in a centrifugal purifier can produce a force （） the force of gravity.
A.many thousand times larger than B.the same as C.many thousand times smaller D.none of the above
The separation of impurities and water from （） is essen...
单项选择题The separation of impurities and water from （） is essential for good combustion of diesel engines.
A.lube oil B.fuel oil C.turbine oil D.grease
Which of the following may hardness of the boiler water...
Which of the following may hardness of the boiler water cause?（） (1) scale formation (2) tube failure (3) corrosion
A.（1）and（2） B.（1）and（3） C.（2）and（3） D.（1），（2）and（3）
