GB1186770A - Process and System for Treating Rubber - Google Patents

Abstract

1,186,770. Separating foreign objects from rubber. FRENCH OIL MILL MACHINERY CO. 14 Nov., 1967, No. 51857/67. Headings B2A and B2H. [Also in Division C3] Foreign objects, such as dirt, sand, twigs and bark are separated from coagulated chunks of rubber by conveying the chunks to a shredder in which they are reduced to smaller pieces for releasing the embedded foreign objects, collecting the pieces within a chamber containing liquid to a depth sufficient to provide for settling of the foreign objects and floating of the pieces, withdrawing liquid with rubber pieces therein adjacent the surface of the liquid in the chamber to form a slurry and draining the liquid from the rubber pieces. The chunks C of rubber, Fig. 1 are fed by means of a conveyor 10 into a screening apparatus 12 which comprises a screen 15, Fig. 2 mounted within a frame 16 supported in an inclined position on a housing 18 by means of coil springs 20. The screen is vibrated by an eccentric weight 22 rotated through belt drive 25 by a motor 24. As the chunks move down the screen 15 they are washed of loosely adhering foreign objects by liquid sprayed from nozzles 27. The washed chunks are received in a hopper 29 to which liquid is added at 38. From the hopper the chunks are fed to a shredder 30 which may be of the type having a rotary drum with a series of axially extending chopper knives around its periphery and a half inch to one inch semi-circular screen. The shredded pieces A of rubber pass through a semi-cylindrical screen adjacent the bottom portion of the shredder drum together with liquid and are received in a settling chamber 40 in a tank 42 which includes an agitation chamber 44 separated from the chamber 40 by a weir 45. Liquid is maintained at level 46, e.g. by topping up as at 48. The relatively heavier foreign objects settle to the bottom of chamber 40 and are removed as sludge by a pump 50. The liquid and floating rubber pieces A flowing over the weir 45 are circulated in the chamber 44 and removed as a slurry by means of a pump P. The slurry may then be fed to a second and, if desired, third stage of washing, shredding and settling. The shredder 60 in the second stage of the twostage apparatus shown may be of the type having rigid hammers and a half inch (or smaller) perforated plate. The slurry from the last stage is fed via a line 68 and a pump 69 to a dewatering screen 12b from which the partially dried pieces of rubber are fed to a dewatering screw press 70 and to a dewatering and drying screw press 75.