GB271780A - Improvements in grinding mills - Google Patents

Abstract

271,780. Hõnel, P. Feb. 10, 1927. Roller mills. - A grinding-mill comprises an even number of grinding-rolls, not less than four, arranged in series so that each roll of the series coacts with two other rolls of the series so as to form a number of grinding gaps equal to the number of rolls, each roll being positively rotated in the direction opposite to that of the rolls with which it coacts and the peripheral speed of the second and each subsequent roll being greater than that of the roll that precedes it. Means may be provided for displacing alternate rolls of the series for varying the widths of the gaps. As shown, four rolls a - - d are arranged to form four grinding gaps 1 - - 4 through which the material being ground passes in succession. The rolls are driven by spur gearing at the ends of the rolls on both sides of the machine, the speed of the rolls increasing from a through b and c to d. A trough e feeds the material to the gap 1 between the rolls a, b, and a scraper f removes the ground material from the last roll d. The rolls a, c may be mounted in stationary bearings, and the rolls b, d may be adjustable by means of screw spindles h, i. To prevent material from adhering to the roll a and passing directly to the last gap 4, a scraper x may be arranged between the rolls and bear against the roll a. The material scraped off the roll a falls on to the roll c and passes through the gap 2.