GB508123A - Improved attrition mill - Google Patents

Abstract

508,123. Rumbles.BOLL, W. H. P. March 28, 1938, No. 9503. [Class 60] [Also in Groups II and XXXIV] A ball mill for grinding material comprises a chamber of cube shape mounted for rotation by diagonally-opposite corners in such manner that during rotation individual corners assume in succession the instantaneously lowest position and that the balls roll in a series of straight lines at angles to one another in moving to the lowest corner, and one of the mounted corners of the chamber includes an expansion bearing. As shown in Fig. 1, the drum 8 of cube form is supported at diagonal corners by ball bearings 16, Fig. 2, housed in sleeves 25 attached to the drum. The ball bearings comprise an inner race mounted on a cone 15 on a feed tube 11, an outer race 18 fixed to side plates 20, and a circumferential plate 19, the latter and the sleeve 25 being slotted longitudinally at four points on the circumference to house balls 24 which permit the drum to expand longitudinally. Lugs 27 are secured on the sleeve and driving sprocket wheels 29 are attached thereto. Material is fed to the mill by a screw 32 rotated by a sprocket 36, the screw being bored for the passage of compressed air to the mill from a pipe 38 rotatably 'connected to the screw at 37. The discharge tube 41 from the mill is venturi-shaped internally and carries externally a ball bearing housed in a sleeve on the drum similar to that shown in Fig. 2. Polished steel balls are added to the material in the drum for the purpose of adding their weight to the mass and causing it to slide freely over the interior of the drum during rotation.