US1780915A - Apparatus for disintegrating ore and other material - Google Patents

Description

Nov. 11, 1930. H. HARDINGE 1,780,915

I APPARATUS FOR DISINTEGRATING ORE AND OTHER MATERIAL Filed Jan. 50. 1929 FIGJ.

Patented Nov. '11, 1930 trans PA T FIQE EAR-LOWE HARDINGE, 0F YORK, IPENNSYLVANIA, ASSIGNOR TO HARDINGE COMPANY,

INCORPORATED, 0F YORK, PENNSYLVANIA, A CORPORATION OF NEW YORK APPARATUS FOR DISINTEGRATING ORE AND OTHER MATERIAL hpplication filed January 30, 1929. Serial No. 336,175.

This. invention relates to apparatus for disintegrating ore, coal, ceramic materials and other materials, of the conical type described and claimed broadly in the United States Patent No. 908,861. In mills of that type the material is disintegrated by agitation in a rotating barrel or drum, preferably aided by a multiplicity of hard balls or pebbles. The barrel is provided with an inlet opening of suitable character, through which the material to be treated is introduced, and with an outlet opening, at the axis of the barrel, through which the ground or disintegrated material is discharged.

It is essential that the shape or form of the barrel backward from the outlet opening be conical. Backward from the base of this conical part, which for convenience may be termed the conical outlet portion or simply the outlet portion, the barrel may be variously formed, and, since it contains the inlet opening, may be conveniently termed the inlet portion. An additional grinding compartment may or may notbe disposed between the inlet portion and the outlet portion. lVhen lumps or pieces of ore or other material, with or without the addition of a multiplicity of hard pebbles, metal balls, or other similar non-friable crushing bodies, are introduced into such a rotating barrel, a very striking result is produced; the lumps or pieces of material, and the crushing bodies, if any are used, arrange themselves according to size, the larger in the part of the barrel having the greatest diameter, and from there diminishing in size toward the outlet opening.

This arrangement or assortment of the material according to size is preserved during the rotation of the barrel about its longitudinal axis, and as a piece or lump of material is broken up by the impact and attrition of the other masses the pieces promptly move forward toward the outlet opening,

where the finest particles escape. It will therefore be seen that the larger pieces, which require heavier impact for their disintegration or reduction, are acted on by the largermasses, and when broken are passed on to a point Where the masses are smaller and hence Where the reducing action is less. In other words, small pieces, which require relatively slight reducing action, are acted on by small masses, and larger pieces by larger masses. In this way the work actually ex: pended upon a piece of anygiv'en size is, in general, proportional to the work required for its reduction or disintegration, and there is no energy wasted in subjecting a small particle to the unnecessarily heavy impact and attrition of heavy masses, or large pieces to the ineffective iinpact and attrition of small masses. H

However, in the operation of such grind- "ing mills, it is frequently found that the material, particularly in the case of very hard or refractory substances, in its final state of sub-division is not so nearly uniform insize as maybe desired. That is, a certain percentage of the particles may be too large for the purpose desired or the subsequent methods employed for reducing the coarser particles. The utilization of this coarser portion of the ore or other material is frequently an important consideration, and it is accord,- ingly-the object of the present invention to provide an improved mill whereby such coarser particles shall be subjected in the mill a longer time to the grinding or reducing action so that the percentage of coarse .rnaterial finally discharged from the mill will be reduced to minimum in amount.

Another object of the invention is to provide a mill which accomplishes the object of subjecting the coarser portion of the material for a longer time to the grinding or reducing action of the larger masses while at the same time retaining the grinding and classification action characteristic of the conical outlet portion of a mill when being operated upon a horizontal axis.

In the accompanying drawing, Fig. 1 illustrates a longitudinal section of a mill embodying the' principle of the invention.

Fig. 2 shows a long type of triple cone mill.

In general, a mill embodying my invention has a conical outlet portion 10 whose conical surface is concentric with theaxis HH of the mill passing through the centers of trunnions 11, 12. These trunnions are open and material is fed to the mill through the inlet opening within trunnion 12 and leaves the mill through the outlet opening within trunnion 11. The mill is rotatabl supported on trunnion bearings (not shownl by which the axis HH of the mill is maintained practically horizontal.

\Vhile the inlet portion of the mill adjacent trunnion 12 may have a wall perpendicular to axis H-H,- it is preferable to use a Wall having a slope substantially the same as the slope of the conical outlet portion 10 and, accordingly, the .inlet portion 13 is illustrated as being conical,

For the purpose of gaming in capacity it has been a former practice to provide a central cylindrical portion between the conical ing greater inclinations than the central portion, and, therefore, the larger masses will be concentrated therein.

So as to control the distribution of the" larger masses in the central portion and to subject the coarse material to a grinding action commensurate with the predetermined size of its particles, the central portion 15 of a mill made in accordance with the principle of my invention is made conical to a slight degree.

The base of the conical inlet portion 13 has the greatest diameter, and the largest masses within the mill will be maintained within the central portion 15 in the vicinity of this largest diameter. A gradual diminution in size of the material and of the grinding masses will exist from the largest diaineter of the centralportion 15 to the smallest diameter of central portion 15 at the base of the conical outlet portion 10. Such amill has greater capacity than any of the type of those illustrated in the aforementioned patent for any given floor space and the use of a conical central portion in themanner proposed herein in placeof a cylindrical central portion is made commercially practicable be cause of the gain in efficiency accreditableto the elimination of a cylindrical central portion in mills of large capacity.

A comparison of a former type of mill hav ing a cyhndrical central portion with a triple cone mill, such as may be had by visualizing,

in Ijig. 1, a cylindrical central portioniand a con cal outlet portion interposed between the conical inlet portion 13 and trunnion 11,

shows very Well the larger capacity to be had in a triple-cone mill and that this increase 1n capacity is obtained without the use of more floor space, the trunnion to trunnion measurement remaining approximately the same.

The capacity of mills of the present type 1 is governed, to a great extent, by the length of the central portion of the mill and by the greatest diameter of the mill. Formerly it has been the practice to'make the length of the central portion about one quarter the diameter of the mill, but a mill of large capacity having this ratio would have a diameter of too great a dimension. The application of the principle herein disclosed renders it possible to obtain a highly eflicient mill of large capacity and one having a greater ratio of length of central portion to the diameter. The use of a conical central portion enables this ratio to be increased and accordingly contributes to the production of an efiicient mill of large capacity without necessitating an increase of the largest diameter.

Dimensions of a practical formof a mill made in accordance With-this invention might include as its largest diameter a measurement of eight feet and a length of eight feet extending from the base of the inlet cone 13 to the base of the outlet cone 10. Giving to the central portion an angle of about 7 in respect to the horizontal makes it possible to increase the angle of the conical outlet portion from about 30 to about 60, for with a conical central portion segregation of material according to size is continually taking place in the central portion and the size of the material in the vicinity of the base of the conical outlet portion is smaller than in the case where the central portion is cylindrical. Accordingly, for a given spacing of trunnion bearings, or of inlet and outlet openings, a mill of larger capacity is obtainable than in the case of a mill having a cylindrical central portion.

- At times it is desired to have a mill which which has a long grinding compartment between the inlet cone and the outlet cone. It has proved ineflicient to merely increase the length of the central cylindrical portion of the former style of mill because of the mixed character of the different sizes of particles of ,material and of impact balls throughout the cylindrical central portion. In Fig.- 2 there is illustrated a long triple-cone mill having a central conical portion 115 whose length is greater than the largest diameter of the mill. This mill has a conical inlet portion 113 which is joined at its base to the intermediate conical portion 115 at its largest diameter and a conical outlet portion 110 which is joined at its base to' the intermediate conical portion 115 at its smallest diameter. Hollow trunnions 112 and 110 constitute the inlet and outlet openings, res ectively, as well as means whereby the mi 1 is mounted for rotation. A long mill of this character requires less power;to operatev for the same volume of material being disintegrated than would be required if the central portion were not conical. I

What is claimed is:

1. A rotatable mill for disintegrating ore and other material, comprising three conical portions joined together with the ends of the intermediate conical portion joined to the larger ends of the conical end portions, the conical end portion at the larger end of the intermediate conical portion having an inlet opening and the conical end portion at the smaller end of the intermediate conical portion having an outlet opening, and a plurality of crushing bodies freely movablein all directions within the mill.

2. A rotatable mill for disintegrating ore and other material in which the degree of crushing action occurring therein is different for every position along its length, comprising an intermediate conical grinding compartment Whose length is greater than its maximum diameter and wherein the greater part of the crushing action takes place, end portions walling the ends of said grinding compartment except for inlet and outlet openings, the wall having the inlet opening being secured to the larger end of the grinding compartment and the Wall having the outlet opening being secured to the smaller endof the grinding compartment, and grinding media of different sizes capable of freely falling in all directions and of segregation according to size within said intermediate conical portion along its axis as the mill is rotated.

3. A rotatable mill for disintegrating ore and other material in which the degree of crushing action occurring therein is different for every position along its length, comprising an intermediate conical grinding compartment wherein the greater part of the crushing action takes place, end portions walling the ends of said grinding compartment except for inlet and outlet openings, the wall having the inlet opening being secured to the larger end of the grinding compartment and the wall having'the outlet opening being conical and having its base end secured to the smaller end of the grinding compartment, and grinding media of difi'erent sizes capable of freely moving in all directions and of segregation according to size along the axis of the mill as the mill is rotated.

In testimony whereof I hereto aifix my signature.

HARLOWE HARDINGE.

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