US1068289A - Tube-mill lining. - Google Patents

Description

W. Av. WHITE &'W. P. SCHMIDT.

TUBE MLL LINING.

APPLICATION FILED MAY 27, 1913.

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UNITED STATES PATENT OFFICE.

WILLIAM ALFRED WHITE AND WILLIAM FRIEDRICH SCHMIDT, 0F EAST RAND, TRANSVAAL.

TUBE-MILL IIINING.

To all whom t may concern le it known that we, llViLLi'AM ALFRED IVX-Irre and WILLIAM Frommen SCHMIDT, both British subjects, residing at li/ltarried Quarters, East Itand Proprietary li/lines, East Rand, in the Province of the Transvaal, Union oit South Africa,have invented certain new and usetul Improvements in lube-llf'lill Innings; and we do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to malte and use the same.

The present invention has reference to linings tor tube mills which comprise longitudinal bars positioned radially to form longitudinal troughs open to the interior of the mill and ot such dimensions as to cause pebbles or like elements ol the mill charge to pack into them and i'orm a wearingl sui'- tace. In conjunction with said bars there is usually a cylindrical lining coveringl the actual shell oit the mill. TWhen such a lining is put into use, the radially placed bars gradually Vwear away, and the lining requires periodically to be renewed. In constructions hitherto used, the radial bars have been retained in place by inserting them between the edges of tlat bars laid longitudinally and flat-wise on the shell of the mill to form the circumferential lining. Consequently, when the liner is worn down to its useful limit, a considerable portion of each radial bar remains unused and is wasted. Moreover', the radial bars wear away more rapidly at the feed end of the mill than at the discharge end ot the same, so that when that portion of the bars nearest the t'eed end ot the mill has worn to the extent to require the lining to be discarded, the other ends ot the bars are still not worn out, but have to be wasted.

It is a purpose of the present invention to .minimize this waste of' material forming the radial bars; to provide improved means for holding said bars in place, and to enable linings to be more cheaply and expeditiously renewed than hitherto.

In the accompanying drawings: Figure I a projected and longitudinally tore shortened view of part of a tube mill lining constructed according to this invention. Figs. II, III and IV are projected views ot the checks hereafter referred to and drawn to an enlarged scale.

Specification of Letters Patent.

Application lecl May 1913.

Patent-,ea July a2, 1913. Serial No. 770,269.

The shell oi the mill is indicated by uuw meral l. It may be provided with a. cylindrical lining' which, as here shown, is constructed of 'llat bars 2 relatively wide as compared with their thickness and positioned longitudinally and flat-wise on the inner surface oi.Z the shell l. They are laid edge to edge and are secured in place in any appropriate manner as by cementing them in place or wedging them together'. This construction of the cylindrical liningl is considered preferable, but it may, if desired, be made ot relatively large plates curved to tit to the mill 0r of concrete or otherwise; or again it may be omitted altogether.

El indicates the longitudinally and radially placed bars forming between them the troughs et in which the pebbles pack. They are positioned wholly within the inner surface of the cylindrical portion of the mill (consisting of the shell l and cylindrical lining 2, it' present), so that the whole ot their depth is available for wear. They are secured in place and spaced. apart in the constructions shown to the left of Fi I, by means ot choclis 5 placed between them. Said checks and the bars are, during construction, forced firmly together, or wedged up it necessary by driving in a tew wedges o in each circumferential series ot choclrs. Said radial bars and choclrs together thus form an independent arch structure having only trictional engage ment with the cylindrical portion of the mill. Some ot the checks, (e. g. those in the circumferential series 5, 5l and 5C Fig. I, and III and IV), or all of them it desired, may have feet 7 which extend under the bars 3 and so keep the checks from talling out oi place during the building of the lining. lVhen the bars 3 seat on the cylindrical part oi' the mill (as indicated by 3a) in order to avoid cutting said bars where they cross over said teet 7, the latter may be sunk in annular recesses 8 provided by separating the edges ot adjacent longitudinal sections of the cylindrical liningbars o z will appear more clearly :from Fig. III.

The radial bars may be spaced away from the cylindrical part ot the mill, for instance by resting them on said feet 7 of the checks, which themselves then rest on the cylindrical lining` 2. This device virtually increases the depth of the troughs fl formed by a given depth of the bars 3 and thus enables the bars to retain pebbles when worn to a greater extent than is the case when they seat directly onto the cylindrical part of t-he mill. The bars may also be sectionalized longitudinally and the sections made narrower and increasingly spaced from the cylindrical part as they are farther from the feed end of the mill. Thus, as shown in the drawings, the middle section 3b of each bar is narrower than section 3 at th-e feed end of the mill and is spaced farther from the cylindrical part than the latter; while sec- 30 at the discharge end is still narrower and still farther spaced. Their radially inner` edges 9 however, are preferably lrept substantially in alinement and parallel with the axis of the mill. By suitably adjusting the depths of the sections of the bars in this manner the variations in the rate of wear at different parts of their length are provided for, and the bar as a whole may be worn down practically simultaneously so economizing material without the expense of rolling tapering bars and without the disadvantage of having the lining, at the outset, of various diameters in dilferent parts. A few of the spaces between the radial bars and the cylindrical part of the mill may be lled up by blocks 1S to stop the pulp contents of the mill from washing freely over the surface of the cylindrical part and so abrading the same.

The ends of the bars 3 may conveniently be supported by means of rings 10. The latter are retained in the angle between the end plates 11 and the cylindrical liner` 2 by any suitable means; for instance by dividing them into sections and driving Wedges 12 between the sections. The inner faces 13 of the rings are beveled away outwardly as shown, or otherwise shaped to retain the bars against inward radial movement and the ends of the bars 3 are complementally beveled or shaped to engage therewith.

1n place of the separate checks 5, angle iron or like rings 14 may be used for supporting the radial bars. Said rings may be divided and be wedged at the points of division 15. They are slotted suitably at 16 to receive the bars 3, which may be retained in the slots by means of wedges 17, or otherwise.

In renewing or 11e-fitting a liner as described, it is only necessary as a rule to dismantle and replace the radial bars 3 and the chocks 5 or the rings 14, as the case may be. As the radial bars are gripped at rela tively few points of small area, viz. where they are engaged by the chocks 5 or the rings 14, they do not require to be quite straight and may be used in the condition in which they ar-e produced by the rolling mill. In the type of lining in which the radial bars are gripped between the edges of the bars forming the circumferential lining, the said radial bars require to be specially straightened, at considerable expense. Moreover, the gripping contact between the radial bars and the circumferential series of chocks, being localized, is better and more easily effected than that between continuous bars.

What we claim and desire to secure by Letters Patent is 1. Tn a tube mill, the combination with the cylindrical part of the mill, of longitudinally and radially positioned bars forming between them pebble catching troughs, and chocks between the bars, said chochs having feet extending under the bars.

2. in a. tube mill, the combination with the shell of the mill, of a cylindrical lining composed of iat bars Vlaid longitudinally of the mill and edge to edge, and longitudinally and radially positioned bars forming between them pebble catching troughs and arranged wholly within said cylindrical lining.

3. In a tube mill, the combination with the cylindrical part of the mill, of separate longitudinally and radially positioned bars forming between them pebble catching troughs, said bars being spaced radially away from said cylindrical part.

et. In a tube mill, the combination with the cylindrical part of the mill, of separate longitudinally and radially positioned bars forming between them pebble retaining troughs, said bars beingspaced away from said cylindrical part unequally at different parts of the length of the mill.

5. Tn a tube mill, the combination with the cylindrical part of the mill, of separate longitudinally and radially positioned bars forming between them pebble retaining troughs, said bars being spaced away from said cylindrical part unequally at different parts of the length of the mill, and the radially inner edges of said bars being rect-ilinear and substantially parallel with the aXis of the mill.

In testimony whereof, we affix our signatures, in presence of two witnesses.

WlLLIAM ALFRED WHITE. WILLIAM FREDRICK SCHMIDT.

ll/Titn-esses ALFRED L. Sroon, WTESLEY E. JOHN.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. C.

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