GB1265637A - - Google Patents

Abstract

1,265,637. Tube mills. ALLIS-CHALMERS MFG. CO. 8 Dec., 1970 [11 Dec., 1969], No. 58228/70. Heading B2A. A shielding device 40, Fig. 1, in a division head assembly 25 of a tube mill prevents migration of media from a fine to a coarse compartment. The tube mill comprises a rotatably-mounted cylindrical shell 1, having a compartment 4 containing media (rods 6) for coarse grinding and a compartment 5 containing media (balls 7) for fine grinding, the two compartments being separated by the division head assembly 25 perpendicular to the rotational axis of the shell, the assembly comprising a pair of spaced-apart annular transverse bulkheads 26, 27, Fig. 2, each having a central opening 37, 38. The openings are connected by an axiallyextending truncated cone-shaped passage whose central axis coincides with the central axis of the shell, the taper of the cone being directed towards the coarse grinding compartment. The shielding device 40 is mounted in the cone-shaped passage and presents a surface which blocks a central portion of the passage and thus prevents reverse passage of the balls. The shielding device has a channel through it to permit passage of material from the coarse to the fine grinding compartment. As described, the shielding device is a disc supported by mounting blocks, 41 Fig. 2, arcuately spaced around its periphery and having a diameter larger than the smaller end of the conical passage. The mounting blocks may be integrally-formed with the disc. The coneshaped passage may comprise a replaceable liner. As shown the bulkheads include liners 28, 29, and liners 30, 35 define the passage, Fig. 2. The mill includes a feeder 15, a discharge screen 19, lifter vanes 20, a discharge trunnion 12 and discharge cone 21, and is driven by a gear 13 secured (as shown) around the inlet end of the casing, or around the feed trunnion 11.