单项选择题
A.the sensor of low oil level is fully covered by sludge
B.the coarse strainer before the pump in suction system is clogged
C.the screw pump is worn seriously and volumetric efficiency is decreased
D.bilge suction value is clogged
单项选择题 The pressure difference of the gauge on the oily water separator increases greatly, the reason is（）
单项选择题 Oily water separator mis-alarms, the most possible reason is （）
单项选择题 Because the flow rate of supply water pump is too large, oily water separator does not work wellWhich of the following is not the reason?（）