Principles of naval engineering - Historic Naval Ships Association

-IPRINCIPLES OF NAVAL ENGINEERINGBELT GUARDMOTOR PULLEY-•SPINDLECOUPLING NUTFUNNEL COVERFUNNEL BODY-[^^*- PURIFIED|j\ OIL OUTLET\ \—CLARIFIERFigure 6-4.— Tubular-type centrifugal purifier. 75.234or as the three-wing . The three-wing rotateswith the bowl and forces the liquid in the bowl torotate at the same speed as the bowl. The liquidto be centr ifuged is fed into the bottom of the bowlthrough the feed nozzle, under pressure, so thatthe liquid jets into the bowl in a stream.The process of separation is basically thesame in the tubular-type purifier as in the disktypepurifier. In both types, the separated oil assumesthe innermost position and the separatedwater moves outward. Both liquids are dischargedseparately from the bowl, and the solidsseparated from the liquid are retained in thebowl.Settling TanksLubrication systems aboard ship include settlingtanks in which used oil is allowed to standwhile water and other impurities settle out. Lubricatingoil piping is generally arranged to permittwo methods of purification: batch purificationand continuous purification.In the batch process, the lubricating oil istransferred from the sump to a settling tank bymeans of a purifier or a transfer pump. In thesettling tank, the oil is heated to approximately160 F and allowed to settle for several hours.Water and other impurities are removed fromthe settling tanks. The oil isthencentrifugedandreturned to the sump from which it was taken.In the continuous purification process, thecentrifugal purifier takes suction from a sumptank and, after purifying the oil, discharges itback to the same sump. The continuous methodof purification is used while a ship is underway.118