PRINCIPLES OF NAVAL ENGINEERING 



BELT GUARD 



MOTOR PULLEY- 



• SPINDLE 



COUPLING NUT 



FUNNEL COVER - 

 FUNNEL BODY- 



CLARIFIER 



[^^*- PURIFIED 

 |j\ OIL OUTLET 



\ \— I 



Figure 6-4.— Tubular-type centrifugal purifier. 



75.234 



or as the three-wing . The three-wing rotates 

 with the bowl and forces the liquid in the bowl to 

 rotate at the same speed as the bowl. The liquid 

 to be centr ifuged is fed into the bottom of the bowl 

 through the feed nozzle, under pressure, so that 

 the liquid jets into the bowl in a stream. 

 The process of separation is basically the 

 same in the tubular-type purifier as in the disk- 

 type purifier. In both types, the separated oil as- 

 sumes the innermost position and the separated 

 water moves outward. Both liquids are dis- 

 charged separately from the bowl, and the solids 

 separated from the liquid are retained in the 

 bowl. 



Settling Tanks 



Lubrication systems aboard ship include set- 

 tling tanks in which used oil is allowed to stand 



while water and other impurities settle out. Lu- 

 bricating oil piping is generally arranged to per- 

 mit two methods of purification: batch purifica- 

 tion and continuous purification. 



In the batch process, the lubricating oil is 

 transferred from the sump to a settling tank by 

 means of a purifier or a transfer pump. In the 

 settling tank, the oil is heated to approximately 

 160 F and allowed to settle for several hours. 

 Water and other impurities are removed from 

 the settling tanks. The oil isthencentrifugedand 

 returned to the sump from which it was taken. 



In the continuous purification process, the 

 centrifugal purifier takes suction from a sump 

 tank and, after purifying the oil, discharges it 

 back to the same sump. The continuous method 

 of purification is used while a ship is un- 

 derway. 



118 



