GB159527A - - Google Patents

Abstract

159,527. Marks, E. C. R., (National Equipment Co.). Sept. 15, 1919. Disc mills.-The invention consists in the improved construction of reducing surfaces on the faces of discs which may be used in refining apparatus of the type disclosed in Specification 17074/12, and is an improvement on the disc construction disclosed in Specification 133,476; Specifications 20861/14 and 108,331 also are referred to. The disc is cast in sectors r with half. holes 10 for attaching to a backing-plate, each sector comprising a series of angularly spaced radial main feeding-grooves 18 extending from the central feed-opening to the inner boundary of an annular series of pockets 20 on the outer portion of the disc, each main feeding- groove being intersected at an acute angle by many auxiliary feeding-grooves 19 so that the substance to be refined may be distributed in fan-like form from the main feeding-grooves to the outer pockets. The main feeding-grooves have one longitudinal face normal to the outer surface of the disc, the other longitudinal face sloping upward from the bottom of the normal face. These grooves are of gradually decreasing depth and width from the centre of the disc, and are of relatively large dimensions compared with the auxiliary feeding-grooves. The auxiliary feeding-grooves are all substantially of the same width and depth having one normal and one sloping face. They are of progressive lengths and terminate at their outer ends in small progressively increasing distances from the centre of the disc. The pockets are in two series one A, B, C, &c. eccentric to, and the other A-A<3>, B-B<3>, &c. concentric with, the axis of rotation of the disc. The number of pockets in each series increases from the inner boundary which is nearer to the centre than to the periphery of the disc, " filling-in " pockets 21 being placed where necessary. The pockets are parallel to one another and to the auxiliary feeding-grooves and their small dividing-walls 22 stop the flow of the substance directly in a radial direction, their dividing-walls 23 preventing the flow directly in a circumferential direction, the result being that the flow between opposed discs takes place in a sinusoidal form throughout the pockets to the periphery. The half holes 10 have meeting- shoulders 12, and to provide a good bearing upon the cast surfaces a washer 15 is disposed between the shoulders and the head of the fixing bolt, the mating-surfaces of the bolt and washer being slightly curved to compensate for irregularities in casting.