GB202906A - Improvements in and relating to roller and ring mills for grinding and crushing coal and the like - Google Patents

Abstract

202,906. Babcock & Wilcox, Ltd., (Deutsche Babcock & Wilcox Dampfkessel- Werke Akt.-Ges.). Dec. 28, 1922. Roller-and-ring mills.-In a mill for grinding or crushing coal &c. of the type in which spring- pressed rollers run against the inside surface of a stationary ring, scrapers or shovels arranged between and rotating with the rollers remove the material from the ring, and revolving conveying- shovels arranged laterally of the ring return the material passing near the ring back to the grinding-track of the ring. As shown, the spindles 3<1> of the rollers 3 are mounted in bearing-boxes 7, which are movable in radial frames 6 fixed to hubs 5 on a shaft 4 and are pressed outwards by springs 8 which can be tensioned by means of bolts 9 and spring plates 10. A scraper shovel 11, which has a number of stepped scraping surfaces or is set at an inclination, is arranged behind each roller, and conveying-shovels 12 placed laterally of the ring run between the roller systems to carry the coal &c. dropping from the side of the ring 2 back into the grinding system. A separating-chamber 13 is placed above the mill and communicates with a fan 15 by passages 14. Air from the burners at which the powdered coal is burnt is drawn into the mill through nozzles 16, and the coarser material separated in the chamber 13 passes back to the mill by the passages 13a. The ring 2 may be provided with two diametrically-opposite inletopenings 17 so that it can be turned when it becomes worn.