US1517509A - Apparatus for classifying granular material - Google Patents

Description

Dec. 2, 1924. 1,517,509

M. HOKANSON APPARATUS FOR CLASSIFYING GRANULAR MATERIAL Filed March 4, 1922 2 Sheets-Sheet 1 10 W I 22 J Dec. 2, 1924- 1,517,509 M. HOKANSON APPARATUS FOR CLASSIFYING GRANULAR MATERIAL Filed March 1 2 Shee.s-Shee! 2 I H L WITNESSESS INVENTOR M g ATTORNEYS Patented Dec, '2, 1924.

UNITED/STATES PATENT OFFICE.

-MARTI1I HOKANSON, OF DULUTH, MINNESOTA APPARATUS FOR CLASSIFYING GRANULAR MATERIAL.

Application filed March 4, 1922. Serial No. 541,168.

To all whom it may concern:

Be it known that I, MARTIN HOKANSON, a citizen of the United States, and a resident of Duluth, State of Minnesota, have invented a new and useful Improvement in Apparatus for Classifying Granular Mate.- ial, of which the following is a specification.

This invention relatesto an apparatus for classifying granular material and has for an object the rovision of a device that will readily .and eciently effect a separation of the particles comprising a granular material into grades or classes according to their respectlve sizes.

Although the device is adapted for general use wherever it is desirable to effect a se aration or classification. according to t e size of the particles comprising the material, it is particularly adapted and intended for use in connection with the separation of the valuable parts of ore from gangue.

It is .a special object to providea device for effecting the desired purpose without the use of screens or shaking tables, in which the separation is produced by utilizing the greater rolling action of the larger particles, in which the material is operated u on while in the form of a thin sheet where y the induced rolling action will eflect a sharp and clean separation of the particles, in which the path of the rolling particles will be of considerable length without necessitating parts of cumbersome pro ortions, in whic the rolling action is a, pos1tively induced one and which can be easily varied to suit varying conditions, and in which means are employed to enhance the effectiveness of the rolling action of the larger particles by preventing or hindering the rolling actlon of the smaller particles of the material.

It is also an object to provide a device possessing a large capacity of production without detracting from its efiiective operation to produce a sharp separation, which is of simple construction, easy to operate and repair, and which can be economically manufactured.

These and other objects of the invention will more readily appear when taken in connection with the following description and the appended claims.

In the accompanying drawings, Fig. 1 is a diagrammatic view with parts in section illustrating one embodiment of the invention; Fig. 2 a fragmentary view of a modified form; and Fig. 3 a transverse sector taken on line IIIIII of Fig. 2.

The embodiment of the invention shown in Fig. 1 comprises a supportin framework consisting of the upright mem ers 1, only two of which are shown, and transverse members 2, said framework resting upon a suitable foundation 3.

Suspended in any desirable way between the upright members 1, and concentrically arranged, are a plurality of annular funnel .shaped collectin compartments 4, 5 and 6 having inclined ottoms and equipped with the discharge chutes 7 8 and 9 respectively. The several annular compartments are suitably connected and spaced apart at intervals by means of vertical sheet separators of well known construction,-those adjacent the top portions being indicated at 10 and those nearer the bottom at 11, the assembled compartments being suspended as a unit by attaching the exterior wall of the outer compartment. 6 to the upright 1 at 12. These compartments may be constructed of any suitable material, preferably of metal, and the space between the inner com artment 4 forms a chamber which is closed loy a top 13 having at its center a bearing 14:. A spider 15 mounted in this chamber also carries a bearing 16 aligned with bearing 14 in which a shaft 17 is journaled, said shaft extending through a tubular prolongation 18 projectin downwardly from the chamber.

The tu ular extension 18 serves as an inner wall for the lower end of compartment 4 and also as a housing for the shaft 17.

Shaft 17 is centered and supported by a foot bearin 19, and attached thereto adjacent the cot bearing is a driving pulley 20 adapted to be driven from any suitable source of power by means of the belt 21.

Attached to the upper end of shaft '17 and disposed immediately above the top 13 is a circular distributingdisk or table 22.

The upper surface of the disk is preferably conical center exposed with the covering extending within a short distance therefrom to the peripheral edge of the disk, or a two part covering ma be employed having the central portion 0 a material possessing the necessary wear-resisting qualities. The upper surface of the disk or table 23 is somewhat higher at its central point in order to distribute the material evenly from which it preferably slopes downwardly along a curved path to its intermediate portion and thence curves upwardly to its periphery, the edge of which is rounded as shown. This rounded edge is of special utility when the material operated upon is mixed with water, in a manner to be presently described, due to the greater surface tension between the water and the table than between the water and the particles of material carried thereby.

The material to be treated is fed upon the table 22 at its center 24 from an agitating hopper 25 suspended at 26 in the transverse members 2, is deposited upon the table at a low velocity, and due to the conical shape of the center of the table it will immediately spread out in the form of a thin sheet. This discharge mouth 27 of the hopper is disposed directly over the center of the table and at a very short distance therefrom, and is provided with a regulating valve 28 towards which the funnel shaped bottom of the hopper gradually slopes.

The feed hopper may be filled in any de sired manner. The embodiments illustrated are particularly intended for use in connection with mixtures of ores and gangue which are introduced through a conduit 29 controlled by gate valve 30, while the supply of water with which it is mixed is introduced by means of pipe 31 rovided with a valve 32. Mounted within t e hopper is an agitator consisting of shaft 33, carrying wings or blades 33, journaled in bearings 34 and 35 supported by spiders 36 and 37, respectively. Attached to the upper extremity of shaft 33 is a bevel pinion 37 meshing with a second bevel pinion 38 fixed to a shaft 39 driven from any suitable source of power. By such means the ore and water can be thoroughly mixed to separate the particles from each other and to maintain the mixture in a uniform condition.

In use, if dry material is operated upon, the granular material is deposited from the hopper at a low velocity, and in such quantity as to insure its being spread out in the form of a thin sheet upon the rotating table or disk 22 by the time it reaches the lowest depression on the table. the difl'erences in sliding and rolling friction between the particles and the supporting surface of the table, and to the fact that the larger particles more easily acquire a rollgether.

Due to ing motion under the influence of the several impelling forces, a rolling action is immediately induced in the larger particles, the lineal velocity of which gradually increases as said particles approach the peripheral edge of the tablc,. the final velocities obtained varying in accordance with their relative sizes. The smaller particles consequently do not tend to roll easily relatively to the larger particles and under practical operating conditions, do not attain but a small velocity relative to the larger particles as a result of their rolling motion.

Due to the above described action it is obvious that by the time the several particles reach the peripheral edge of the table, the largest particles have assumed a high velocity away from said edge, and the smallest particles a comparatively low velocity, while the particles of intermediate size acquire a velocity therebetween. The largest particles are therefore projected the greatest distance from the table and are caught. in the outer annular compartment 6, the smallest particles fall into the inner compartment 4, and those of intermediate size are collected by the middle compartment 5.

In the embodiments illustrated only three compartments are used which separate the particles into but three grades. The same principle of separation applies, however, rcgardless of the number of collecting compartments employed, so that by varying the number of said compartments the number of grades into which the particles are separated may be varied at will.

Although a similar separation is efl'ected by using a table of the form shown without a covering of material, such as rubber or canvas, the difference between the rolling motion induced in the large and small particles with the consequent difference in their final velocities is greatly enhanced by its use.

The operation so far described has had reference especially to the treatment of materials in a dry condition in which the several particles do not cling tightly to- It is impossible to effect a clean separation of certain materials due to their normally moist condition or because of the presence of substances which act as binders to cause the particles to stick to each other. If the materials are thoroughly mixed with water so as to free theparticles from each other and this mixture fed, as above described, upon the table, and allowed to spread out in the form of a thin sheet, the separation will not only take place in the manner set forth but will be more pronounced. This results apparent- 1y from the fact that the rolling action of the larger particles are practically 12nafi'ected by the presence of the sheet of Water on the table. while-the smaller parti- Ill) cles are submerged to a greater or less exv crease in the diflerence in the final velocities assumed by the varying sized particles with a consequent. sharp separation into. grades or classes. a

The preferred contour of the upper surface of the table has been illustrated in which the travel of the material during its initial movement from the center thereof is in a downwardly curved path under the combined action of centrifugal force and gravity, and as it approaches the edge of the table is in a path curved upwardly over which it moves under the action of centrifugal force. The exact form shown is merely illustrative and may be varied to meet varying conditions of operation necessitated by changes in the material handled and its relative characteristics, but

is so designed as to cause a positive rolling action of the material until it'actually leaves the edgeof the table. It is obvious that the exact form of the table depends also upon the speed. at which the table is rotated, and that for the same form of ta ble a comparatively wide range of control may be secured by suitably regulating its speed of rotation to change the centrifugal force tending to move material being treated.

While the device is adapted to effect a separation according to size of particles of granular material generally, the form illustrated is primarily intended and designed to effect a separation of the larger particles of gangue from the smaller particles of ore in a mixture of ores and gangue, and is particularly useful in segregating the gangue and ore particles after a preliminary classification has been effected to obtain a mixture containing gangue and ore particles which will be suspended in equilibrium by the same vertically upwardly flowing stream of water. A classification to procure such a mixture may be effected by any method or device, such as by feeding an ore containing gangue, substantially different in specific gravity, to devices such as disclosed in my previously filed applications, Serial No.

,245,296, filed July 17, 1918, and Serial No. 272,327, filed January 21, 1919, details of which, however, are not necessary to an understanding of the present invention. By such devices a mixture of gangue and .ore particles is secured in which the size of the gangue particles vary within cer tain limitsand in which the ore particles also vary within certain limits, but all of which willbe suspended in equilibrium by the same vertically flowing stream of water. [As an example of such a graded or classified mixture, one containing silica tite particles ranging from .1 to .04 inch in diameter might be given. If the-mate- ;rial of the example just given mixed with water is fed upon the rotating table, the silica particles because of their greater size will be ejected from the table at a decidedly greater velocity than the hematite particles which are of smaller size. Consequently, if the velocity of the table is properly regulated substantially all the silica particles will fall into,the outermost compartment 6 and if the other compartments are of proper width substantially all the ore particles will drop into the inner compartment 4. Due to the fact that the smallest silica particles are of substantially the same size as the largest hematite particles, a certain number of silica and hematite particles because of their corresponding size will attain substantially the same velocity. These particles are caught by the intermediate compartment 5 and can be subsequently treated in any of the well known ways to effect a separation due to the difference in specific gravities of the two materials. Applicants separator therefore possesses particular utility in the concentration of ores of the character named.

As above stated, and with the material taken as an example, the particles which fall into the intermediate chamber 5 are partly hematite and partly silica, all particles however being of substantially the same 'size. The particles of silica are therefore considerably li hter than the particles of hematite. if a blast of air of suitable intensity is forced upwardly through the chamber 5, the lighter particles of. silica will be deflected upwardly without appreciably affecting the path of travel of the heavier particles of hematite. By properly regulating this upward blast, it is obvious that a very largev number of the silica particles can be made to pass over into the outer compartment 6 reducing 'those falling into the intermediate compartment to a minimum, thereby effecting a. decidedlycleaner and sharper separation. In F igs. 2 and 3 is illustrated a modified form of device utilizing the upwardly flowing air blast in the intermediate compartment.

In this modifiedform, an annular chamber 40 surrounds the lower reduced extremity of compartment 5 to which air under pressure is supplied through the pipe 41 having the interposed control valve 42-. The chamber 40 is placed into communication with the interior of the compartmentby a series of equally spaced apertures 43 extending through the wall of the compartment. In order to prevent the escape of air downwardly through the outlet 8, the same is provided with a water seal by directing particles ranging from .25 to .1 and hemasaid outlet below the surface of water contained within a vat, as indicated at 44.

From the above description, the mode of operation of this form is obvious. The valve 42 is opened to an extent to admita sufficient quantity of air to cause an upward blast through the compartment 5 which will deflect the lighter silica particles causing them to travel over into the outer compartment while retaining theheavier hematite particles within the intermediate compartment, otherwise operating in identically the same manner as the form previously described.

It is thus seen that the invention provides a device for separating granular materials composed of various sized particles, which is simple in construction, easy to operate, economical to manufacture, void of all screens or shaking tables, and while adapted for general use is'particularly useful in the concentration of ores or for similar purposes.

I claim:.

1. An apparatus for grading granular material according to the size of the particles composing the same, comprising a laterally extending distributing disc or table having its entire upperplain surface exposed and operative to retard sliding movement of said particles and to induce rolling action thereof, means for rotating the disc, and means for separately collecting the different sized particles discharged therefrom.

2., An apparatus for grading granular material according to'the size of the particles composing the same, comprising a lat erally extending distributing disk or table having its entire upper plain surface freely exposed and provided with a covering hindering the free sliding action but inducing rolling action of the particles, means for rotating the disk, and means for separately collecting the different sized particles discharged therefrom.

material according to the size of the particles composing the same, comprising a distributing disk having its upper face unobstructed and freely exposed throughout its entire extent, means on said disk for enhancing the rolling action of the particles, means for rotating the disk, and means for separately collecting the different sized par ticles discharged therefrom.

4. An apparatus for grading granular material according to the size of the particles composing the same, comprising a distributing disk, the upper freely exposed plain surface of which is unobstructed throughout its entire extent and slopes gradually downwardly from its central portion to a point intermediate its center and peripheral edge and thence upwardly to the said edge whereby to increase the rolling action of the particles, means for rotating the disk, and means for separately collecting the different sized particles discharged therefrom.

5. An apparatus for grading granular material according to the size of the particles composing the same, comprising a distributing disk, the upper surface of which slopes gradually downwardly from its central portion to a point intermediate its center and peripheral edge and thence upwardly to the said edge whereby to increase the rolling action of the particles, the said peripheral edge being rounded, means for -rotating the disk, and means for separately collecting the different sized particles discharged therefrom.

6. An apparatus for grading granular material according to the size of the particles composing the same, comprising a dis tributing disk having its upper face unobstructed and freely exposed throughout its entire extent, a covering on the said disk for enhancing the rolling action of the particles, means for rotating the disk, and means for separately collecting the different sized particles discharged therefrom.

7. An apparatus for grading granular material according to the size of the particles composing the same, comprising a distributing disk the upper surface of which slopes gradually downwardly from its central portion to a point intermediate its cen ter and outer edge and thence upwardly in an unbroken curve to the said edge, and a covering on said disk whereby to increase the rolling action of the particles, means for rotating the'disk, and means for separately collecting the different sized particles discharged therefrom.

8. An apparatus for grading granular material accordin to the size of the particles composing the same, comprising a distributing disk having itsupper face unobstructed and freely exposed throughout 3. An apparatus for grading granular its entire extent, a rubber covering on said disk for enhancing the rolling action of the' particles, means for rotating the disk, and a plurality of concentrically arranged compartments spaced from the disk for separately collecting the particles of varying size discharged therefrom.

9. An apparatus for grading granular material according to the size of the particles composing the same, comprising a distributing disk having its upper face unobstructed and freely exposed through its entire extent, the upper surface of which gradually slopes downwardly from its central portion to a point intermediate its center and peripheral edge and thence upwardly in an unbroken curve to the said edge, and a rubber covering on said disk whereby to increase the rolling action of the partiunobstructed and freely expose cles, means for rotating the disk, and a plurality of concentrically arranged compartments spaced from the disk for separately collecting the particles of-varying size discharged therefrom. 1

10. An apparatus for grading granular material according to the size of the particles composing the same, comprising a distributing disc having a plain u persurface d throughout its entire extent and operative to retard sliding movement of the said particles and to induce rolling action thereof, means for feeding the material upon the disc in the form of a thin sheet, means'for rotating the disc, and a plurality of concentrically arranged annular compartments spaced at different distances from the periphery of the disc for separately collecting the particles of varying size discharged therefrom. '11. An' apparatus for grading granular material according to the size of the particles composing the same, comprising a distributing disk having a plain upper surface unobstructed and freely exposed throughout its entire extent, means for feeding the material on the disk in the form of a thin sheet, the upper surface of the disk sloping downwardly from its central portion to a point intermediate its center and peripheral edge and thence upward" ly in an unbroken curve to the said edge whereby to increase the ro lling-j action of the particles, means for rotating" the disk,

- and a plurality of concentrically" arranged annular compartments spaced at different distances from the periphery of the disk for separately collecting the particles of varying size discharged therefrom. j

12. An apparatus for I grading granular material, according to the size of the particles composing the same, comprising a distributing disk having its upper surface unobstructed and freely exposed throughoutits entire extent for enhancing the rolling action of the particles deposited on the disk, means for rotating the disk, a plurality of concentrically arranged compartments spaced from the disk for separately collecting the particles of varying size discharged from the disk, and means for directing a blast. of air upwardly through an intermediate compartment for upwardly deflecting the lighter particles passing therethrough.

.13. An apparatus for grading granular material, according to the size of the particles composing the same, comprising a distributing disk having its upper surface unobstructed and freely exposed throughout its entire extent, a covering thereon ofiering high frictional resistance to sliding movement of the particles deposited thereon whereby to induce rolling action thereof, means for rotating the disk, a plurality of concentric annular compartments spaced from the disk, and means for directing a regulated blast upwardly through an intermediate compartment for deflecting the lighter particles passing therethrough.

14. Apparatus for grading granular material according to the size of the particles composing the same, comprising a distribut' ing disk having its upper surface unobstructed and freely exposed throughout its entire extent and so shaped as to' induce a rolling action to the particles, means for rotating the disk, a plurality of concentrically arranged compartments spaced from the disk, and means for directing a regulated blast upwardly through an intermediate compartment for deflecting the lighter particles passing therethrough.

15. Apparatus for grading granular material according to the size of the particles composing same, comprising a distributing disk having a plain upper surface unobstructed and entire extent, means of feeding the material on the disk in the form of a thin sheet, the upper surface of the disk having a covering hindering the free sliding action but inducing rolling action of the particles, means for rotating the disk, and a plurality of concentrically arranged annular compartments spaced at different distances from the periphery of the disk for separately collecting'the particles of varying size discharged therefrom.

In testimony whereof, I sign my name.

F. H. CURTIS, JOHN D, Emerson.

freely exposed throughout its

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