GB251665A - Improved method of grinding or crushing - Google Patents

Abstract

251,665. Barthelmess, E. May 2, 1925, [Convention date]. Mills and apparatus.-In grinding and crushing materials by pneumatic or hydraulic means, the materials in a container are subjected by means of air or liquid under high pressure to a rapid circular movement so that they are ground by centrifugal impact with the container walls. The fluid may be directed longitudinally into the grinding-chamber, and pieces of harder material such as flint stones may be added to the materials under treatment to increase the grinding action. Fig. 1 shows a pneumatic apparatus in which the air blast from a blower d is introduced longitudinally into the grinding-chamber b by a pipe p into which the materials to be ground are fed continuously at c. The air and finer particles pass through a sorting-device e surmounting the chamber b and through a pipe q into a cyclone separator f,from whence the air is returned by a pipe r to the blower. The size of the particles entering the pipe q is regulated by means of adjustable flaps h, and the coarser particles are returned to the chamber b through a central funnel s fitted with pivoted flaps q. Fig. 2 shows an hydraulic device in which liquid is fed tangentially into the grinding-chamber b by means of a pump i, the materials to be ground being fed directly into the chamber at c<1>. The overflowing sludge is received in a surrounding tray t from which a pipe q<1> leads to the upper part of a closed separator f<1> fitted with a series of superposed conical settling-rings m, The pump i draws its supply from the separator, and the ground materials which settle in the separator are discharged at l. In a modification, Fig. 3, suitable for the reduction of ores, the grinder is fitted with a bell mouth u, whence the sludge overflows on to a baffled settling-bed o where the ground ores are separated off.