US991317A - Ore crusher or grinder. - Google Patents

Description

G. JOHNSTON. ORE GRUSHER 0R GRINDER. APPLICATION FILED AUG.4.-1910.

Patented May 2, 1911.

- Z'SHEETS-SHEET 1.

. e. JOHNSTON. ORE CRUSHER 0R GRINDER. APPLICATION FILED AUG. 4. 1910.

2 SHEETS-SHEET 2.

Patented May 2, 1911.

GEORGE JOHNSTON, OF CHIHUAHUA, MEXICO.

ORE CBUSHER OR GRINDER.

Specification of Letters Patent.

Patented May 2, 1911.

Application filed August 4, 1910. Serial No. 575,583.

T 0 all whom it may concern:

Be it known that I, Gnonon JOHNSTON, a subject of the King of GreatBritain and Ireland, residing at Chihuahua, Mexico, have invented an Ore Crusher or Grinder, of which the following is a specification.

Auriferous quartz, banket material and other hard ores or substances after being broken down into suitably small pieces, are commonly crushed or ground by stamps, ball mills and the like to a sufficiently fine condition to admit of further treatment thereof. Such crushing or grinding apparatus is however of great weight and cost, is expensive to transport and erect, requires heavy and secure foundations and is, com pared with its output, costly to operate.

When roller mills are used for crushing or grinding hard materials of the kind referred to, the rolls are usually of large and substantially equal diameters driven at comparatively slow speeds and arranged to form between their upper converging surfaces a deep hopper-like space that is kept charged with the material to be crushed and ground. With such an arrangement the material forms between the upper portions of the rolls, a comparatively deep wedge shaped mass that is subjected to lateral compression between the rolls, whereby it tends to move upward as well as downward and cause slip and ineflicient working, and a heavy lateral unbalanced thrust is also produced on the roll bearings which causes considerable wear and necessitates frequent renewal thereof. Such roller mills are moreover very heavy and expensive to operate.

Now the present invention has for its object to enable auriferous quartz, banket ma terial and other hard ores or substances (hereinafter referred to for brevity as ore) to be crushed or ground to the desired degree of fineness in a quicker, cheaper and more convenient manner than heretofore usual and with apparatus that can be constructed, transported and erected in a quicker, easier and more convenient manner than that heretofore usual and by means of which the milling cost for each ton of ore treated, can be considerably reduced as compared with the milling methods and means now commonly employed. For this purpose, ore is crushed or ground by feeding it, with or without water, at a comparatively slow velocity, say of the order of several hundred feet per minute, and in a comparatively thin stream between a pair of rolls one of which is made of small diameter and the other of relatively large diameter and both of which have a high peripheral velocity of the order of say ten thousand feet per minute and upward, so that the successive portions of the stream of material are practically subjected individually to a sudden nipping or crushing action between the adjacent portions of the rolls in a manner analogous to that which would result if pieces of hard material were fed consecutively between a rapidly acting hammer and an anvil. In this way a large quantity of ore can be easily, quickly and cheaply dealt with.

In apparatus suitable for carrying out the invention, it is advantageous to use two pairs of small and large diameter rolls arranged with their axes parallel, the two smaller rolls being arranged adjacent to each other and between the two larger rolls so that lateral thrust on the smaller rolls is balanced and their bearings thus relieved of undue wear. Two pairs of rolls thus arranged may constitute a milling unit. two or more such units may be mounted side by side, that is to say in parallel, upon a common base plate or support or upon separate base plates or supports and be driven in any convenient manner from a driving shaft common to them, suitable ore feeding means being provided for simultaneously feeding ore between each pair of rolls.

In the accompanying illustrative drawings, Figure 1 shows in side elevation, and Fig. 2 partly in plan and partly in horizontal section with the feeding means removed, one arrangement of crushing or grmdmg apparatus according to the invention. Fig. 3 is a plan of the apparatus to a smaller scale, showing the feeding means in positlon.

In the example shown, the apparatus comprises two crushing and grinding units each comprising a pair of rolls a, b of small diameter, say for example twenty inches in diameter, arranged adjacent to each other and between a pair of rolls 0, d of large diameter, say for example sixty inches in diameter. The rolls are fixed upon parallel shafts e mounted in bearings f fixed upon a metal base piece or support 9 built up of angle iron or otherwise suitably constructed, each shaft 6 being common to a pair of rolls belonging to both units and provided with a belt pulley 7L. 2' is a driving pulley fixed upon a driving shaft 74 that is mounted in bearings m on the base piece 9 and is provided with a driving wheel or pulley n by which it can be rotated at a high speed. 0 is a loose pulley. Or the shaft 76 may be driven direct at a high speed, as by a steam turbine. The Various rolls are driven simultaneously at a high speed from the driving pulley 2' by an endless band 79 passing around that pulley and the pulleys '71, in the direction shown in Fig. 1 so that the rolls a, b in each unit rotate in opposite directions to one another and to the adjacent rolls 0 and (Z. Each roll, which is preferably made of small width, say about eighteen inches, is made with a hard peripheral crushing or grinding surface. F or this purpose it may conveniently be provided with a renewable sleeve of hard steel, such as hardened cast carbon steel, suitably fixed in place on the roll core or body. The several rolls, arranged at a distance apart to produce the required degree of fineness of the material passed between them, may run in contact with each other near their outer sides and be provided with peripheral grooves Q with a view of preventing ore fed thereto escaping laterally outward.

The ore feeding means in the example, comprises a launder 1 through which the ore is fed with water and from which itis dis tributed. into hopper-like receptacles s, 6 through the bottom of which it falls in thin streams between the adjacent pairs of rapidly rotating rolls?) (Z and a 0 respectively where it is subjected to the rapid crushing and grinding action hereinbefore referred to. The excess of water, with any float gold or other matter in suspension therein, flows onward from the receptacles s, 25 into a common discharge launder u. The entrance to each receptacle sis provided with a perforated distributing plate 1), through which some of the ore passes to the receptacle be low, the remainder passing on to the recep tacles t.

The rolls in each pair may have the same peripheral speed or different peripheral I speeds.

Two or more roller mills such. as described may be used through which the ore is successively passed so as to reduce it to the desired degree of 1 stages.

What I claim is 1. A crushing or grinding unit comprising two pairs of rolls of different diameters, the rolls of each pair having their crushing surfaces in cooperative relation to receive the material to be reduced between them with .the smaller diameter roll substaining the lateral shock of the material being reduced thereon by the larger diameter roll, the smaller diameter rolls of the two pairs being arranged between the larger diameter rolls and running in contact to balance the lateral thrust thereon of the material being crushed, means for rotating said rolls, and means for simultaneously feeding material between both pairs of rolls, substantially as described.

2. crushing or grinding unit compris- 1 ing two similar pairs of rolls of different diameters having their axes in a common plane, each pair consisting of a positively driven smaller diameter roll and a positively driven larger diameter roll having their crushing surfaces in cooperative relation to receive and reduce the material between them, the two smaller rolls being arranged I between the two larger rolls and running in contact to balance the lateral thrust thereon due to the simultaneous reducing action of the rolls of the two pairs on the material therebetween, means for positively and simultaneously rotating all of said rolls, and means for simultaneously feeding material to both pairs -of rolls, substantially as described.

Signed at New York this 26 day of July 1910.

GEORGE JOHNSTON.

Washington, D. G.

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