GB999521A - Method and apparatus for controlling the interior contour of a tumbling mill - Google Patents

Abstract

999,521. Grinding mills. HARDINGE CO. Inc. Aug. 28, 1963 [Sept. 17, 1962], No. 34007/63. Heading B2A. An autogenous or ball mill includes a shell supported for rotation on trunnions 16, 18, Fig. 1, and lining means connected to the interior of the shell and comprising elements of relatively high, medium and low heights detachably arranged around the interior surface of the mill so as to permit adjustment of the inner contour of the mill, by replacement of elements to compensate for wear. As described, the aforesaid lining elements are provided both on the inner periphery and conical ends of the mill. Liner segments 24 are bolted adjacent the conical end 12, the edges being shaped to receive the bolted radial wedge and lifter bars 26, 28 of successively greater height. The peripheral portion 10 of the shell has curved liner segments 30, 32 with inner surfaces sloping towards each other. Medium and high wedge and lifter bars 34, 36, respectively, extend between the edges of the liner segments 30, 32, and are bolted by wedge bolts 38, and spaced as in Fig. 5. Grate sections 40 are bolted at the exit end and circumferentially spaced to receive the radial lifter bar sections 42, 44 also of successively greater heights. A space 48 receives material discharged through openings in the grates, and lifter blades 50 in the space carry material upwards until it falls under gravity against the conical end 52 of the mill and is discharged through an exit cone 22. Deflecting rings 54, 56 effect transverse movement of material axially within the mill. When a medium height bar 34<SP>1</SP>, Fig. 7, becomes worn, the high bars 36<SP>1</SP> have worn down to medium height and the bar 34<SP>1</SP> is then replaced by a high bar, so as to preserve a similar contour in the mill. Thus alternate medium and high bars are progressively changed in position around the mill with each replacement. In a modification, the grate is spaced at its periphery from the interior of the peripheral portion of the mill and an additional deflecting ring protects the grate from excessive abrasion. A further embodiment employs a cylindrical casing with liner segments extending between opposite ends of the mill, and alternate longitudinally extending high and medium height lifter bars, which may also be provided at the ends of the mill. The lifter bars may be of two-part construction, comprising wedge portions and upper portions, secured by wedge bolts extending through both portions as well as the shell plate ; as wear occurs, the upper portions only are replaced. In a further embodiment, the liner segments are flanged so that flanges 88, Fig. 9, on successive segments are receivable in recesses 90 formed along opposite sides of the lifter bars 92, 94. By clamping the segments 86 relative to the shell, the bars 92, 94 are operatively secured. In a still further modification, liner and lifting sections 106, 110, 108 of successively greater heights are provided as shown in Fig. 11. Specification 949,791 is referred to.