单项选择题
In a disk-type lubricating oil purifier, （）
A.the purifier driving gears are lubricated by the reclaimed
B.oil as it leaves the bowl all dirt and sludge are automatically discharged with the cooling water
C.sealing water must never be supplied until after oil is fed to the unit
D.deterioration of the bowl ring gasket will cause the purifier to lose its water seal
相关考题
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单项选择题
In sewage treatment, the term maceration refers to the process of （）
A.breaking up solid matter into fine particles
B.precipitating non-decomposed waste in a collection tank
C.chemically adjusting the sewage ph to 7-0
D.eliminating bacterium coli from the sewage -
单项选择题
Which of the equipment listed is most effective in processing bilge slops for overboard discharge?（）
A.100PPM oily water separator
B.Assembling the lube oil purifier as a separator and aligning bilge overboard
C.A 15PPM oily water separator
D.A magnetic duplex strainer -
单项选择题
If you heard a ‘crackling’ noise in centrifugal pump, the most probable cause of the problem would be（）
A.insufficient speed
B.cavitation
C.excess discharge pressure
D.excessive net positive suction head B
