GB251524A - Improvements relating to grinding and mixing mills for mortar and other materials - Google Patents

Abstract

251,524. David, M. Oct. 14, 1925. Continuous-discharge apparatus with stationary containers. - In grinding and mixing mills for mortar &c., of the type comprising a cylindrical casing containing a rotary central shaft carrying a series of grinding and mixing runners that can move radially and rotate on their own axes, the runners extend the whole length of the casing and are constructed so as to convey the material from the feeding to the outlet end of the mill. As shown, Figs. 1 and 2, the central shaft 7 carries end plates 13, 14 having four radial slots 16 to receive sliding blocks 35 which carry the shafts 17 of the runners 18. The blocks 35 may have trunnion-like extensions slidably engaging grooves in the edges of the slots 16. Two of the runners 18 are provided on their front ends with right-handed threads which extend over about one-half of the length of the runner and the depth of which decreases towards the rear. The third runner has parallel circular grooves on the front half of its length while the fourth runner has a left-handed thread on the rear half of its length. All the runners are slightly conical with their larger ends towards the front of the mill. The open rear end 11 of the casing 1 forms an enlarged hollow portion 29 which contains a ring conveyer 27, 28 bolted to projections 26 of the rear plate 14. A false bottom of resistant material is provided in the lower part 2 of the mill. The materials to be treated are introduced through a feed-hopper 22, which may be fitted with a spray pipe 23, at the front end of the mill, and the disintegrated and mixed materials are discharged by the conveyer 27, 28 through a sleeve conveyer 31 to the outside of the mill. In a modification, Fig. 5, the front plate 13 is provided with one or more scraper plates 33 to facilitate the feed, and series of inclined scraper plates 45, Fig. 6, may extend from the front plate 13 to the rear plate 14 and between the runners. The plates 45 may be pivoted to a rod 42 secured to the plates 13, 14. and also to a parallel rod 43 which is adjustable longitudinally to vary the inclination of the plates. One or more scrapers 33<x> on the rear plate 14 direct the treated material into the outlet conduit 40. When treating moulding sand, some of the runners 18 may be replaced by runners consisting of end discs carrying longitudinal crushing-bars of circular, ovoidal, or other section. In some cases, cylindrical runners with parallel circular grooves are used.