CASTOE-OIL INDUSTRY. 



29 



A centrifugal machine (fig. 14) has been devised departing in some 

 respects from the ordinary basket or cone centrifuge, which has been 

 found quite satisfactory on a laboratory scale for removing from the 

 oil large quantities of the sticky albuminlike product which on long 

 standing settles from oils and which so seriously impairs the capacity 

 of the filter press. This machine by removing such meal and other 

 substances as are difficult to 

 filter out leaves an oil with 

 only a thin cloud, but which 

 can be treated with fuller's 

 earth, bleached, and filtered 

 with much greater ease than 

 with the bulky precipitate 

 retained. The walls of this 

 centrifuge are solid and not 

 perforated, as in the laundry 

 type. A series of baffles (fig. 

 1 5) attached alternately to the 

 wall and to the central shaft 

 forces the oil to take a deviat- 

 ing course through the centri- 

 fuge, result- 

 ing in the col- 

 lection of the 

 precipitate in 

 the lower por- 

 tions of the 

 centrif ug e 

 somewhat 

 similar to the 

 throwing out 

 of moisture 

 from steam 



when the latter passes through the trap or catchall in a vacuum 

 entrainment. (Fig. 11.) 



The hot oil with its charge of fuller's earth and carbon is then 

 pumped through an ordinary plate-and-frame filter press, the 

 cloths of which should be covered with paper in order to obviate the 

 trouble and difficulty of washing out the adhering earth from the 

 pores after each filtration. All that is necessary in this case is to 

 wash the cloths with alkali after several runs in order to remove the 

 oil without the attendant rubbing necessary to clean up the pores. 

 The filter papers with their charges of earth and carbon can be lifted 

 off the cloths and thrown into the solvent extractors, thus greatly 



Fig. 14.— A centrifugal separator. 



