Patent GB-1054249-A (GB)
IPC: B02C15/12
Abstract: 1,054,249. Ball-and-ring mills; roller-andring mills; continuous discharge mixing appliances. J. R. BEREND. Feb. 13, 1964 [Nov. 13, 1964], No. 42786/62. Headings BIC and B2A. Apparatus for processing material, as by grinding, mixing or homogenizing, comprises a processing surface 5, Fig. 1, a plurality of processing elements, eg. balls 1, at least part of the surface of each engaging and rolling over the surface 5, a<SP>1</SP>spacing member 8 between adjacent elements, and a driving member 3 to cause the elements to move relative to and to roll on the processing surface. As described, two rings of balls I separated by a disc 2, keyed for axial but non-rotational movement to the shaft 3, are in contact on one side with a concave race on the disc 2 and on the other side with a concave processing race 5. Pressure is applied to the balls 1 by exerting force on a top plate 7. The spherical spacers 8, which separate the balls 1, are maintained against the spheres 1 by a surface 9 in a bushing 10 which is supported on the shaft 3 by bearings 11 in a member 12 keyed to the shaft, so that the bushing 10 and member 12 slide while the bushing 10 may rotate independently. A block 13 supports the lower ring of spheres 8 and resilient pads 16 between an upper block 13a and the lower block exert resilient pressure on the spheres 8. In operation, material, e.g. to be ground, is fed in at 17, falls on to the outer surface 18 of the rotating block 13a, is thrown on to the upper processing surface 5 and ground and thence falls to the lower surface 5 where it is further ground and leaves the machine via the outlet funnel 19. Cooling air is introduced tangentially by a duct 20, and cooling water is fed into an annular chamber 21 by an inlet 22 and flows out via an outlet 23 to cool the fixed parts 6 bearing the processing surfaces 5. Material is prevented from entering the bearings 11 by the outward turning configuration of the gaps 25, between the disc 2 and the bushing 10. In a second embodiment for dry-grinding coal, air is introduced into a vortex chamber 27, Fig. 3 (not shown), and material to be ground falls on to a rotating distribution core 28. Pressure is exerted on the processing race 5 by a hydraulic member 30. Air and entrained ground material leave via a gap 31 and a duct 32. In a further embodiment, a single ring of spacing spheres maintains two parallel rings of balls correctly spaced, and the balls are driven by axially outer races formed on supporting members keyed to the shaft. The spacing spheres may be replaced by suitably shaped rollers on axles integral with upper and lower spindles, which are mounted via bearings on the driving shaft. Alternatively, the central disc may be supported on the shaft by bearings, the spindles being keyed to the shaft. The spheres may be replaced by ovoid rollers 42, Fig. 10 (not shown), free to roll between races 4, 5 and separated by spacing rollers 37 mounted on bearings-supported spindles 39 or spindles keyed to the shaft 3, or alternatively separated by spacing balls. Such an arrangement is suitable for grinding soft bulk material, e.g. talc. The spheres 1 may be driven over a processing race 5 by spacing rollers 37, Fig. 12 (not shown), which can roll over a convex complementary race 43, which is keyed to the shaft 3, or alternatively the mounting spindle 39 for the rollers may be driven and the convex race held stationary. Alternative forms of processing elements may be cylindrical rollers coacting with a convex processing surface, or concave or convex rollers co-operating with a convex or concave processing surface. Flat processing surfaces may be used and more than one of the surfaces may be driven. More than two processing surfaces may be used in series. The apparatus may be used with recirculation of coarse material from a separator, the carrying air being cleaned and recycled to the air inlet.