US 840802 A
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STATES PATENT OFFICE. I GREENLEAF WHlTTIER PTCKARD, or AMESBUY.- MASSACHUSETTS',
ASSIcNoR. To HUFF ELEcTRoSTATic SEPARAToR coMPANY, or BoSToN, MASSAGHUSETTS, AcoRroRATioN-'OF MAINE.
` ELECTROSTATIC 'sEPmaAl-'QFLt i l ed new and useful Improvements in E lectro-v static Separators, of vwhich the following yis a specification.
My lnvention relates to electrostatic separators, and has for its object the improved eiciency of such apparatus and it consists of certain improvements hereinbelowdescribed.
My improved apparatus is intended and adapted to separate particles of solid material which are differentiated from. each other by their susceptibility to receive and respond to electrostat1c charge on bein brought into effective contact with the cdi Typical examples of Such mixtures of solid particles are -to be found in metal-bearing ores in their mixtures with gangues and earths of practicall no value.
` In the drawings llereto annexed,- Figure 1 is a vertical cross-sectionoof a portion of an electrostatic separator, showing the arrangement of electrodes; and Fi 2 shows, on an enlarged scale, a portion o one of the electrodes and a cross-section of one of the subdivisions of the opposite electrode.
l Referring to Fx 1, A is a portion of the casing or frame o an electrostatic separator upon whichis mounted a hopper B, which may be ofany suitable construction whereof the purpose is to deliver comminuted material, as through the aperture C, to theelectrode E, which is shown as a cylinder mountl ed to rotate in the direction indicated by the arrow upon a shaft D. i The opposite electrode is divided into a number of subdiviserves in the usualway to direct the fall of those portions ofthematerial which are se'- lected by the effect of the electrical charge manifested at the two electrodes. l Such particles as cling tothelarger electrode E are wiped or brushed therefrom by the wiper G, which, ,as herein shown, is mounted upon lSpecistuat'ion. of Letters Patent.' Application ned January 29,1906. serial No. 293.331.
Patented Jan. 8,'190i7,
rods g, which slideinholes, as h, in thesoclet-pieces H, the wi er ybeingvheld pressed agalnst the electrode as by a Spring h.
The subdivisions E are connected by wiresy to the main branch Y of the electrical circuit and the electrode Eis connected, as
b y wire X, which is the ,other branch of the c1rcu1t, these branches emanating from the source S of electrical energy, which is' conventionally illustrated inthe drawings. The
exciting apparatus which I prefer to employ 1s such a one as is described 1n Letters Patentl No. 796,011, dated August 1, 1905, issued to me as asslgnor to Chaides H. Huff.
Each of the ,subdivisions E of the elec trode opposed to the repelling-electrode E is placed so that its electrical roximity to the ,electrodeE is closer than to t e next adjacent subdivision E. I employ the term electrical proximity because itis q'u so to arrange the subdivisions M with their dielectric envelops e that the electrodes E themselves are in closer proximity measured in actual distance to each other than to the larger electrode E, and-yetby reason of the presence of the dielectric envelops e they are electrically closer to the electrode E than to each other. This condition maybe explained by reference to Fig.` 2. The dielectric permeability of the envelop e being superior ite possible to that of the .surroundin air the arrangement'andconcentration o the lines of force Ibetween the subdivision E and the repellingelectrode E is the same iin substance 4as the subdivision E were lplaced in the position velop. Thus another subdivision E might be so placed that the two subdivisions of the elect-rode would be nearer toeach other by special measurement than either to the out any dielectric enlarger electrode E but, electrically speaking,
Consequently by the arwere'opposed to the repell ing-electrode, and
intense fields separated by intervals of far inferior intensity. If the subdivisions of the o posed electrode were nearer toeach other, eiectrically speaking, than to the repellingthere are generated therefore a succession of electrode, the result would be a dispersion-ot` lines of force and a deterioration of intensity, the extreme condition being represented, say, by a number of wires very close together strung parallel to each other and to the surface of the repelling-electrode, each of the Wires being electrically much closer to its,
4ap arently occurs at or near the concentrated iie d between the uppermost of the subdivisions E and the repelling-electrode E; but
the passage of the material through the successive regions of h i h concentration-of field enables the electrica lstress to search out the remaining susceptible particles and to rcmove them from the inert portion of the `mass VWhich either falls Within the barrier of the divider F vor is brushed from the electrode E by the Wiper G.
What I claim is- In an electrostatic separator, a repellin electrode; means to feed material thereto, an4 opposite electrode divided into a lurality of subdivisions eac-h of small supergcial extent' as contrasted With the repelling-electrode and each of said subdivisions being inclosed in a dielectric envelop, to bring the subdivisions into closer electrical proximity to the repelling-electrode thanto each other, and means for electrically exciting the sa'id electrodes.
Signed by me at Boston, Massachusetts, this 25th day of January, 1906.
' GREENLEAF WHITTIER PICKARD. Witnesses:
JOSEPH T. BRENNAN, GRACE'E. GIBBoNs