GB544397A - Improvements relating to the refining of dry materials - Google Patents

Abstract

544,397. Centrifugal separators; jet pulverizers. INTERNATIONAL PULVERIZING CORPORATION. July 28, 1941, No. 9566. Convention date, July 31, 1940. [Classes 23 and 59] Solid materials of different particle sizes or different specific gravities are separated centrifugally after being fed into a circulating stream of gaseous medium moving at a high velocity ; the smaller particles with some gas are withdrawn from the inner region while the larger particles form a load circulating under the influence of centrifugal force and are periodically discharged. While the circulation is proceeding the particles are reduced in size by impact and abrasion. This may be achieved in an apparatus substantially of the type described in Specification 432,191. A shallow cylindrical chamber 10 has a number of jet openings 14 in its periphery so that gaseous fluid can be injected from a header 16 to maintain a vortex in the chamber. Material, such as clay or pigment is supplied to the hopper 19 from the conveyer tube 20 by a worm 21 and is fed by an injector 22 into the vortex. The. smaller particles are carried to the central portion of the vortex and pass into the separator 24 where the small solid particles drop to the small discharge outlet 26 while the gas passes from the separator by the axial discharge conduit 27. The larger particles are thrown to the periphery of the vortex chamber and while they continue to whirl, more of them are broken up and the small parts continually move towards the centre Eventually the heavy particles are discharged through the aperture 31 which is opened by the valve 32 operated by a piston 39 actuated by fluid supplied through the pipe d'. The admission of fluid to the cylinder 30 by pipes d<SP>1</SP>, b' is controlled by a slide valve 42 which is operated by a rod 49 in one direction and by a spring 43 in the other. The proper sequence of operations is obtained by means of a rotating cam disc 53, Fig. 4, which carries cams 66, 52 the former of which operates a clutch member 72 so that the feed of material by the conveyer 21 to the hopper 19 is interrupted when the cam 52 operates the rod 49 to move the slide valve 42 to the position causing discharge of the heavy particles.