GB721085A - Improvements in or relating to pulverisers - Google Patents

Abstract

721,085. Ball-and-ring mills. BABCOCK & WILCOX, Ltd. Feb. 10, 1953.[Feb. 12, 1952], No. 3753/53. Class 59. The non-rotary upper grinding ring 21 of a ball-and-ring mill is so formed as to expose major portions of the upper outer quadrants of the grinding balls 20 for the reception of recirculated material and is provided with a series of circumferentially spaced lugs 80 projecting outwardly therefrom and having curved undersides 81 forming continuations of the ball race 22. The opposite faces of the lugs are downwardly inclined in the direction of rotation of the lower grinding ring 18. The pulverised material is removed from the grinding area by means of an annular stream of a gaseous medium, e.g. air, which is directed upwardly and outwardly away from the row of grinding balls by means of a plate 43 which co-operates with a ledge 40 on the lower grinding ring to form a throat 42. The upper face of the lower grinding ring is cut away at 18a so as to form a material storage pocket inwardly of the ball race 19. Stationary deflector ploughs 69 are provided above the throat 42. Pressure is applied upon the grinding rings and balls by means of springs 25 which also prevent rotation of the upper grinding ring. The raw material to be pulverised is supplied by means of a regulatable table feeder 35 through an opening 36 to the inclined surface of a drive yoke 17 carrying the lower grinding ring. The material-laden air passes laterally to a classifier 60, the lower end of which surrounds the upper end of the yoke 17 which carries blades 68 which return oversize material from the classifier to the inner end of the row of grinding balls. Particles of dense unpulverised material drop through the throat 42 and are discharged through a gate 50 into a compartment 51. A portion of the throat plate 43 is cut away at one segmental section to accommodate a pivotally-mounted counterweighted relief gate 70 which allows large pieces of unpulverisable material to drop into the subjacent part of the mill. Specifications 523,753, 646,686 and 687,026 are referred to.