US832826A - Magnetic ore-separator. - Google Patents

Description

PATENTED OCT. 9, 1906.

H. H. WAIT.

MAGNETIG ORB SEPARATOR'.

APPLICATION FILED MAR. 20, 1905.

2 SHEETSSEEET l.

wiaeskseay No. 8323-826. PAVTEHTED OCT. 9, 1906.

H. H. WAIT.

MAGNETIC ORE SBPZARATOR.

APPLICATION FILED MAR- 20, 1905- v BEETS-sum 2.

UNITED s'r rns PATENT OFFICE.

HENRY H. WAIT, OF CHICAGO, lLLINOIS, ASSIGNOR TO INTERNATIONAL SEPARATOR COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF NEW JERSEY.

MAGNETIC OREHSEPARATOR.

Specification of Letters Patent.

Patented Oct. 9, 1906.

Application filed Maren 20,1905. Serial No. 251,073.

rator, and has for its object to provide a machine which will be especially effective for g the separation of ores of very low magnetic permeability, which separation requires the action of an extremely intense and concentrated magnetic field.

In magnetic attraction the movement of the permeable particle is always in the direction of converging lines of force-that is to say, the movement is toward the densest portion of the magnetic field. In accordance with my invention an extremely dense and concentrated field is formed by constructing the opposing magnetic pole-pieces between which the separating-field is established in the general form of two wedges facing each other at an angle, preferably at right angles, and the material to be separated is passed between these opposing magnetic crosswedges, so that the more permeable particles are attracted to the surface of one of them, which therefore is made movable in order that the attracted material may be removed at a point distant from the place of separation.

A further feature of myinvention consists of the provision of electromagnetic coils so placed as to oppose the assage-of lines of force in certain paths to irect these lines of force into other paths from which they would otherwise tend to stray, the object being to produce a more concentrated magnetic field than would otherwise be possible.

My invention will be more particularly described and further features thereof pointed out in connection with the accompanying drawings, which illustrate a magnetic separator embodying said invention.

Figure 1 is a vertical sectional elevation of the ore-separator. Fig. 2 is a plan view thereof, the trough for feeding the ore being omitted for clearness and the auxiliary magnet-coi ls being shown in section. Fig. 3 is a ridgethat is tureaxis.

diagram of curves, illustrating the intensities of the magnetic field at different points and also illustrating in a dotted curve a variation in the distribution of the flux to producea larger field of a common density at the particular place desired, as may be accomplished by the use of the auxiliary magnetizing-coils, hereinafter to be described. Fig. 4 is a detail sectional view on line 4 4 of Fig. 1, showing the relation of the auxiliary magnetizingcoils to the armature or revolving separatingcarrier. Figs. 5, 6, and 7 are diagrams illustrating different forms of pole-pieces and the distribution of the magnetic flux secured in each case.

The same letters of-reference indicate, the same parts wherever they are shown,

Referring first to Figs. 1 and 2, the magnetic separator consists of a ma net-frame, preferably of hollow box form, wit inwardlyprojecting pole-pieces N and S and suitable magnetizingwindings therefor, creating a magnetic flux from one to the other-that is tosay, the pole-pieces being of opposite polarity. Between the pole-pieces the armature B is rotatably mounted, the journals of the armature-shaft being at neutral points in the sides of the magnet-frame. The ore or material to be separated is arranged to be fed by means of a chute D between the face of the armature B and one of the poleieces N. In accordance with my invention t e armature B and pole-piece N are formed so as to present ridges facing each other and extend-' ing in lines at an angle to each other. More particularly describing the machine illustrated, the end of the pole-piece N is beveled above and below, so that it is formed like a wedge, with its edge in a horizontal plane facing the armature B. The armature B, on the other hand, is beveled upon its two sides, so that a section of its edge oppositethe polepiece N would also be in the form of a wedge. Thus we have the armature formed with a circumferential ridge facing a pole-piece, the end of which is formed to present a ridge at right an les with the plane of the armatureto say, parallel with the arma- By this means it will be seen that the magnetic flux between the polcpiecc N and the arn'laturc B will be highly concentrated upon the projecting circnnifcrential edge of said armature at the point opposite the pole-piece N. The direction of the magnetic lines of force will therefore be widely divergent from the extremity of the peripheral armature-ridge toward the opposing edge of the wedge-shaped pole-piece N at right angles. The feed-chute D is arranged to direct the material to be separated into the space between the circumferential ridge or edge of the armature and the opposing edge of the magnet-polethat is, intothe densest portion of the magnetic field. The edge of the pole-piece is preferably provided with a non-magnetic shield E to prevent the particles. of material being treated from coming into a position where the influence of the pole-piece N is stronger than that of the armature 13.. F and G are divider-plates for separating the magnetic materiahwhich tends to. fall straight down away from said armature.

In. order to concentrate the lines of force more effectually in the separating-gap. between the armature and the ole-piece N, I preferably provide the a 'ary countermagnetizing coilsA A at the end of the pole-. piece N and at either side thereof. The magnetiz' current sent through these coils should e in. the direction toproducemagnetic fluxes surrounding said coils in such a direction as to. assist the flux between the poles piece N and the armature B, where said pole piece and: armature most closely approach that is,,at the separating-gapwhile opposing theleakage-tlux from theextreme edgesot said pole-piece N toward the armature. In other Words, the Location and magnetization of the auxiliary coils should be such asv to, prevent lines of force from straying from the outer edges. of the pole-piece toward the armature and to direct such lines of force through the portion of the pole-piece which is directly 0 posite the edge of the separati -armature. '1 his feature of my invention will e useful in many forms of magnetic separators, the idea bemg in. eneral to provide auxiliary magnetzingmoifs so. wound and located as. to prevent the undue dispersion of the magnetic flux and to. concentrate such flux at the part cular point where extreme density is re qpired for efiectiive, magnetic separation.v In Big. 3 I have illustrated b means of curves the variation in the distri ution of magnetsm which may be produced by such auxiliary counter-magnetizing coils. The curve H represents the magnetic density at the surface of the revolving armature, the density being taken at the intersection of a horizontal plane through the center of the armaturathe surface L bei developed into a straight line for the sake 0 sim licity. The actual form of the surface is in, 'cated in the dotted lines. The intensity of the magnetic iield at the surface is indicated in the diagram by the dis tance to the right from the surface line L.

Without the counter-magnetizing coils A A the density ofthe flux-would be indicated in a general way by the curve H, and if we consider that the minimum density required for separation is represented by the distance of the line K K from the line L it will be seen that the eXtent' of surface having the required density is com aratively limited, being indicated by the istance X X upon the line K K. By the addition of the compensating windings A, as indicated in Figs. 1, 2, and

4, the magnetic flux at the ridges M M of the armature-surface more remote from the central ridge is decreased, While the flux from that portion of the surfacenearest the central ridge is considerably increased. The result is not only a much higher density at the extreme edge of the circumferential. ridge, but also a larger area of the surface represented by the distance Y Y upon the line K K is permeated with a flux of the minimum separating strength. In other words, the amount of surface of the armature having a magnetic strength sullicient for an effective separation is increased, so that the capacity of the machine is increased.

Referring to Figs. 5, 6, and 7, the theory upon, which the pole-piece and armature are formed to secure the required concentration oi} the magnetic field will be apparent. The force of adhesion is a, function of the magnetic density. In the case of feebly magnetic substances it is necessary to have a very high magnetic density in order to get any consideraiile degree of attractive force. The simplest means of obtaining a very high magnetic density is by means of two pole-pieces of a general conical, form, as indicated in Fig. 5. In order to use such magnetic densities in a continuously-acting commercial ore separator, I have made one ol the suriaccsin the form of a revolving wheel or drum B, a cross-section of which at the periphery would be wedge-shaped. II. the coni 'al form for the magnetic pole which opposes the revolving Wedge B is retained, as shown in Figs. 6 and 7, it will be seen that the lines of force diverge from the stationary pole that is to say, the density will, be higher at the surface of the stationary polo than it will be at the surface of the moving pole. This is undesirable, since it is intended that the magnetic particles should be attracted, but toward the stationary pole, not toward the revolving pole, so that the attracted material may be readily removed. in the form shown in Figs. {5 and, 7 the density will not he as high on the surface of the armature as it is on the conical point, partly on account of the spreading of the lines of force toward the circuml'crcutial ridge of the armature and mrtly because the magnetic reluctance ol' 1 1c air-gap is decreased, thereby increasing the saturation of the pole-yucca) N, which was already wm'liing at a very high magnetic density. i therefore prefer to make the pole-piece N in the form of a wedge, with its edge at right angles to the wedge-sha ed surface ,of the armature, as shown in igs. 1 and 2. The body of the pole-piece is thus reinforced, thereby decreasing the saturation, so as to partially com ensate for the extra saturation at the wor 'ng point.

The armature is preferably laminated, so as to avoid eddy-currents and permit the ar-,. mature to be turned in the intense magnetic field with the minimum expenditure of ener y;

lhe location of the armature between two opposing pole-pieces of opposite polarity, as shown, not only tends to approximately balance'"the"inagnetic pull upon the armature, but also insures the establishment of a neutral point upon the surface of the armature between the two poles, at which point even the more strongly-attracted material will be released.

The operation of the machine will be apparent from the foregoing description of its structure. The material to be concentrated is fed into the feed-chute D and the armature is rotated in the direction of the arrow, the field-magnet being energized by electric current through the magnetizing-coils. As the armature rotates the more ermeable particles of ore will be attracted to its surface, the magnetic flux from the pole-piece N becoming denser as the surface of the armature is approached, and the pole-piece N being further shielded by the non-magnetic plate E the more permeable particles adhering to the armature are carried around in the rotation thereof past the divider-plate F and are discharged on one side of said divider-plate,

while the non-magnetic particles continuing their course are discharged on the other side of the divider-plate G. a

It will be apparent that my inventionis capable of modification, and I do not'desire" to be understood as limiting myself in all re-' spects to the precise construction shown in the drawings; but 7 I claim 1. In a magnetic separator, the combinationwith a revolving magnet tapered from approximately its axial center to its periphcry to form a wedge, of a magnet-pole taperingat its end, with the edge thereof in proximity to the edge of said revolving magnet and at an angle thereto, and means for feeding material to be separated into the gap between the edges of said opposed magnets. 2. In a magnetic separator, a revolving magnet comprising a shaft and a plurality of disks mounted thereon, said disks being of gradually-decreasing circumferences on each side of the longitudinal center of the magnet, thereby forming a magnetic wedge, a we'dgev shaped magnet-pole with its edge in proxe iinity to the edge of said revolving magnet and at .an angle thereto, and means for feedingmaterial to be separated into the gap between the edges of said magnets.

3. In a magnetic separator, the combination with opposing pole-pieces of opposite polarity, of an armature mounted to rotate between said pole-pieces and tapered from approximately its axial center to its periphery to form a wedge, said armature being transversely .laminated, one of said polepieces being tapered in a general wedge shape, with its edge at an angle to the edge of the armature-wedge, and means for feeding material to be separated into the gap between said last-mentioned pole and said armature.

4. In a magnetic separator, the combination with a revolving laminated carrier tapered from approximately its axial center to form a working surface of wedge-shaped cross-section, of magnet pole-pieces of opposite polarity disposed on opposite sides of said carrier, one of said pole-pieces being constructed in a wedge shape, with its edge crossing the wedge-shaped surface of said carrier approximately at right angles thereto, and means for feeding material to be separated into the gap between the edges of said opposed magnets.

5. In a magnetic separator, the combination with opposing magnetic surfaces forming a working magnetic gap, of main magnetizing-coils for establishing the magnetic flux, and auxiliary counter magnetizing coils adapted to provide a magnetomotive force in opposition to theleakage-field, whereby the flux is concentrated in the working gap, substantially as set forth.

6. In amagnetic separator, the combination with a revolving magnetic carrier and a magnet pole-piece adjacent thereto forming a workin magnetic gap, of magnetizing-coils for estab ishing a flux through said gap, and auxiliary magnetizing-coils at the sides of said gap establishing a magnetomotive force in opposition to the leakage-field at the sides of said gap, whereby the flux is concentrated and directed across said working gap, substantially as set forth.

7. In a magnetic separator, the combination with a revolving laminated armature havinga working surface of wedge-shaped cross-section, of magnet-poles of opposite polarity facing said armature, magnetizingcoils for establishing a flux between said poles and said armature, auxiliary counter-magnetizing coils near the end of one of said polepieces at the sides thereof, said last-mentioned pole-piece being of wedge shape with its edge substantially at right angles to the plane of the wedge-shaped armature, and means for passing material to be separatedinto contact with said armature, and through the gap between said armaturc and said lastnnentioned pole-piece, substantially as set forth.

8. In a magnetic separator, thecombina- In witness whereof- I hereuntov subscribe tion with kopposing magnetic surfacesform- I my name-this 13th day of'March, A. D. 1905. ing a wor ing magnetica of m-ma netizing-coil at one side of said ggp. adapted to op- HENRY W I 5 'pose the leakage-field and to direct theflux Witnesses:

across said working gap, substantially as set IRVING MACDONALD, forth. DE WITT O. TANNER.

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