GB206879A - Improved method of and means for pulverising coal and other materials - Google Patents

Abstract

206,879. Duffield, F. L. May 18, 1922. Impact pulverizers.-In disintegrating or pulverizing coal &c., the material is introduced into a chamber or casing at the bottom thereof, subjected therein to repeated. impacts in zones of increasing area by rotary elements, and caused to move upwards through such zones and strike against stationary elements, all under the combined influence of centrifugal force, gravity, and suction whereby the material rises, circulates, and falls until finally drawn off in powdered form at the top of the chamber. As shown, the coal is fed from a hopper k through an opening b at the base of an inverted conical casing a in which rotates a vertical shaft c mounted in ball bearings c<1> and carrying arms or beaters d secured to carriers e. Stationary beaters f fixed to the casing are formed with openings g through which air is drawn by a fan h at the top of the casing, the ports g opening into the casing in the direction of the rotation of the beaters d. The beaters d are preferably arranged in staggered relationship and may be formed with canted faces, and the stationary beaters f with similar faces but sloping in the opposite direction. A motor j drives the shaft c, and secondary air is admitted near the top of the casing by a valve m. The pulverized material is withdrawn by the fan h and forced through a pipe i to the furnace &c. One of the Provisional Specifications describes apparatus in which the material is fed in at the top of a conical casing containing a rotary shaft carrying beaters of triangular section and having pockets, the pulverized material being forced upwards and out through a pipe by the air current set up by the rotary beaters.