... to be discharged outlet,discharge overboard through water discharging 3-way valve,first,second change valve(N.O,N.C solenoid ... open,compressed air should enter into top pneumatic cylinder of three 3-way valves,drive piston downward,close the N.O port,open ... dirty oil tank through top water adsorber/discharging oil 3-way valve N.C port. Bilge Oily Water Separator