US1470597A - Rotary pulverizer - Google Patents

Description

Patented Oct. 16. 1923.

UNITED STATES PATENT OFFICE.

JAMES JOHN DENNY AND ROLLA BARNUM WATSON, OF COBALT, ONTARIO, CANADA.

ROTARY PULVERIZER.

Application filed December 3, 1921. Serial No. 519,593.

fication and illustrated in the accompanying drawings, that form part of the same.

The objects of this invention are to minimize the wear in pulverizing or granu- 'lating machines such as used in the pulverizing of ores. thereby lessening the cost of operation and obtaining the maximum service of the machine, and further to provide an improved liner for the machine which will be materially lighter than the formof'liners at present in use and will therefore absorb less power.

A still further object is to obtain the maximum service from the grinding me- 5 dium.

The principal feature of the invention consists in providing a lining for rotating pulverizers of a resilient wear-resisting material. I

In the drawings. Figure 1 is a perspective view of the cylinder of a ball pulverizer showing the preferred form of lining.

Figure 2 is a section perspective view similar to Figure 1 illustrating a different form of liner.

Figure 3 is'a diagrammatic illustration of a'ball mill showing the location of the balls in operation.'

In the practice of grinding of'ores it has been the custom to line ball granulators and rotating tube mills with wear-resisting materials such as manganese steel, white iron, silica blocks, etc., against which the grinding medium in the form of steel balls or hard pebbles of flint or like material impinge in the rotative action of the mill. Such types of liners are extremely heavy and thereforerequire a considerable amount of power to rotate the mills. A considerable loss is sustained through the wear of the grinding medium operating against the extremely hard liners. These liners wear out very quickly and require the frequent shutting down of the machines for the purpose of renewal which in addition to material cost results in a very heavy labor loss.

The present invention contemplates a radical change in that the liner is formed of a material of light weight having great resilience and high resistance to wear through the impact of heavy bodies thereagainst and when worn such linersmay be replaced at the minimum expense of time on account of the ease with which they may be handled.

This improved form of lining is preferably produced in the form of strips of rubber material substantially the same as that used for the tread rubber of automobile tires, which has been found in practice to be a very eflicient resistant to wear.

The strips 1 as illustrated in Figure 1 are placed around the inner circumference of the cylinder, the flexible nature of the material allowing them to conform to the circular shape. A lining in such form requires the minimum of fastening devices for bolding it in place. If desired, the liner may be formed of a single slab of a width equal to the length of the cylinder. If desired the liner may be formed of slabs or bars 2 of a suitable resilient material placed longitudinally of the cylinder as illustrated in Figure 2.

Alining formed of rubber material while sufliciently hard to resist wear, is of a very tough nature but ithassuflicient resiliency to cause the steel balls or other grinding medium to rebound therefrom upon impact in such a manner as to avoid disintegration of the liner surface. Further, the rebounding action of the grinding media produces a very marked increase in efliciency in the pulverizing of the ore between such media.

' Such a lining is infinitely light in weight than those heretofore used, consequently the heavily weighted mill will be greatly lightened with the result that much less power is expanded. Furthermore, the replacement of. the rubber lining is a comparatively simple matter and may be effected very rapidly.

What we claim as our invention is 1. In a rotary pulverizer, the combination with the rigid shell and the loose grinding balls, of a lining of resilient material interposed between the shell and the balls and adapted to be temporarily depressed b the balls in immed a e c n ac th w t.

during the rotation of the pulverizer, said ing balls, of a lining of semi-hard vulcanized resilient material by its yielding and fricrubber forming the inner wall of the shell tional character being adapted to carry the and compressible under the weight of the 1 balls and the material upward with the mass of balls to form an undulating contact 5 minimum amount of slippage. surface to lift the balls.

2. In a rotary pulverizer, the combina- JAMES JOHN DENNY. tion with the rigid shell and the loose grind- ROLLA BARNUM WATSON.

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