GB331877A - Improvements in grinding or crushing mills - Google Patents

Abstract

331,877. Robinson, G. H. April 10, 1929. Roller-and-ring mills are provided with means for imposing an initial load upon the rolls so as to produce a grinding action between the same and the grinding ring before centrifugal action comes fully into operation. The grinding rulls d are each mounted in a carriage c pivoted to a carrier or spider b, the direction of rotation being such that the rolls lag behind the points c' at which the carriages are pivoted to the carrier. The carrier b is mounted on a vertical or horizontal spindle a which is driven direct or through bevel gears l enclosed in a casing containing oil which is pumped through the bearing by a pump v. Each carrier c is bored to receive a fixed spindle g on which is mounted a roller d either by ball or roller bearings or by a sleeve. The roller d is recessed at each end to take a ring i and thrust washer k, piston ring packing being inserted in the circumference of the rings i to prevent escape of oil from the bearings which are supplied with oil from a central bore m in the shaft a through flexible tubes n and ducts n<1>, n<2>, n<3>. The carrier is provided with upper and lower discs o, o' to prevent access of material to the springs q or r which press the rollers d against the grinding ring e. The springs r may be of ribbed rubber formed in such manner that the load is not unduly increased as the rubber is compressed. The material to be ground is fed in by a screw s<1> whereby it is distributed to shoots or scoop-like devices t rotating with the mill and having their delivery ends located in advance of the corresponding grinding roll. A plough u, rotating with the mill, picks up and delivers the material which has passed through the rollers, back again to the rollers for further grinding. The ground material. may be removed by a current of air.