US977570A

US977570A - Process of electrostatic magnetic separation.

Info

Publication number: US977570A
Application number: US34969806A
Authority: US
Inventors: Henry M Sutton; Walter L Steele; Edwin G Steele
Original assignee: Individual
Current assignee: Individual
Priority date: 1906-12-27
Filing date: 1906-12-27
Publication date: 1910-12-06
Anticipated expiration: 1927-12-06

Description

I H. M. SUTTON & W. L. & E. G. STEELE. PROCESS o'r ELEGTROSTATIG MAGNETIC SEPARATION.

' APPLIOATIONIILED- DEO. 27, 1906. 7,977,571), Patented Dec. 6, 1910.

2 SHEET B-BHEET 1.

a E [A /Woks Ha ry /i7; 514270, By Walk/Z. fiieelwfdmw 5100M H. M. SUTTON W. L. & E- G'. STEELE. PROCESS or BLEGTROS'I'ATIG manna snmm'rxou. APPLICATION FILED D150. 27, 1906. 977,570. Patented Dec. 6, 1910.

2 sums-SHEET 2.

0 -i INVENTORS 0 Hwy/71. Juitozz, 0/ B y Mite/L. Steele e i'dzl/mffifeele.

Attorney UNIT sT TEs- PATENT onnren.

HENRY m. sorrow, WALTER I. STEELE, NnEnwi e. STEELE, or DALLAS, Taxes. 7

Paocnss or Enncraosrerrc'imennrm SEPARATION.

To all whom it may concern: Be it known that we, HENRY M. SU'rroN,

VALTER L. STEELE, and EDWIN G..STEELE,' citizens of the United States, residing atv Dallas, in the county of Dallas, State of Texas, have invented certain new and use-.

' ful Improvements in- Processes of Electrostatic agnetic Separation, of which the followin is a specification, reference being had-therein to the accompanying drawing.

This invention relates to a process ofseparating the particles of a massor the components of a mixture which is in the nature of an improvement upon the process ented to us on November 25th 1902 in Patent pat- . #714,256, and on February th, 1906 in while in a magnetic field.

Patent #813,063, and the invention consists in subjecting the mass of particles to be separated to theaction or influence of magnetic and electrostatic-action, the latterbeing in a constant charge produced b an electrode havin a pointed or shar ene termination, or hy an electrode aving a rounded termination, the charge'supplied to which being non-continuous orinterrupted, whereby'in either case there is set up and maintained a dielectric polarity in particles of the mass being treated: In other words, the invention consists in subjecting the maparticles thereby electricallyreleasing them from an electrode.

The invention consists in further details of operation hereinafter set forth". and described in, the claims. v

While we do not confine ourselves to any particular form of apparatus for the 'em-j odiment or use of our process, we have herein shownan apparatus adapted to that Referr n to the drawingsforming a part of this specification :--Figure 1 represents in 5 diagrammatic relation the principal .ele-

ments of an apparatus to be used in prac-.,

ticing our process; Fig. 2 is an illustrative diagram presented for thepurpose of rendermg the description of the princi les of the invention more readily understoo Fig.

3is a side elevation of aninterrupter shown in edge view in Fig. 1; Fig. this an illus-.

Specification of Letters Patent.

Application filed December 27, 1906. SerielNo. 349,698.

' several figures of the'drawings. y

We have heretofore discovered that by tration of the-wave form produced by said. 1nterrupter;,Fig.5 is a modified arr'angement 0 theap a-ratus shownin Fig. 1 and involves the su stitution of a diflerent form Patented Dec. 6,1910. i

of interrupter; Fig. 6 is a detail of a portion 'of the interrupter shown in Fig. 5; Fig. 7 is the wave form produced by the interrupter shown in Fi 5; and Fig. 8 is still another modified orm ofthe apparatus which is also ada ted for the embodiment of our process,

re resent wave forms.

ike numerals refer to like employing an electrode having a sharpened or pointed terminal in connectlon with an opposing electrode, a continuous charge pah'ses mm the pointed electrode to the other and produces in such particles of the mass as partsin the I i I igs. 9', 10, 11 and 12 possess dielectric pro erties a polarity which. in connectlon with t e. polarity of the elec-- 4 trode with which they, are in contact serves to cause them to adhere to the same. This principle of our invention may be more readily understood by a reference tothe diagram shown in .Fi 2. Let A represent a source of high tenslon electricity whiclumay be either dynamic or static, as shown in this case, and let B be an electrode terminating in a point. Let C bean opposing/electrode and D a hopper or any other suitable device for feeding materialto the electrode 0.

The electrode C and the source of energy A may each be connected either directly to the 1 ground, as'shown at E and F, respectively, by closing the switch G; or the electrodes B directly connected by opening theswitches and G and the source of energy A may be Gr and H and closgg. the switch I, as ,is j 1' clearly a parent that 1s,

1th either connection; I irectly through the switch I, or

through the earth, the resulting effect of the passing charge between the two electrodes is the same. Assuming the-charge to be pass ng usly fromthe point and being and fiuming a partlcle J of the material being treated 'as having passed from the hopper in contact with the electrode 0 inter-- cepting the path of the charge, the result is that the particle'becomes polarized and that equally, one half thereof will be and the adjacent half toward the electrode will be The electrode. being. connected to the earth or to a source of energypermits a'continuous passage of the currenttherethrough,

and therefore has practically no density of charge thereon but there is a bound or induced charge, plroduced inductively by the polarity of t e particles, at the )OlIlt im mediately adjacent to the place 0 its contact with the; electrode C and ofan opposite polarity, towit consequently 'there,exists between the electrode and particle at the place of contact'therewith opposite polarities, and said particle is retai edin contact with the electrode so lon as t at condition exists. It will be noticed at this result of retaining the particle in contact with electrode in the manner described by the use of a continuous current from a pointed electrode is directly the 'oppositeof the result produced by a'current or charge supplied to a rounded e ect rode, as in that case t ere isno binding charge produced, and cons'equentl the palticle and the electrode" Chem 0 the me olarity the rtile is' repelfiad ther rom yv reason'of' e similarity of polarity In our present'precess we have a de d to the attractive forte generated in the particle. t e stop he mag" by convectively delivered charges or additional feature of-provi in neticattractive force acting in unison with the static force whereby certain particles. of

- certain materials which may be compara tivelyfeebly influenced by either a static or .magnetic force, both forces are utilized and therefore the attractive attachment of such particles is enhanced and their separation from their fellows 'more completely accomroper to. state at this point that we have discovered that the same advantageous results maybe produced by our process with a round electrode in place ofa pointed electrode by providin I means for interrupting the convectively elivered charges passing therefrom "to the opposite electrode, and we therefore include as a featureof our process the interruption of the convectively delivered charges whenever rounded electrodes are employed, and furthermore, we apprehend as included within our invention such other, various modificationsand changes as may be suggested to persons skilled in the art and m the elec trical sciences involved so lon as the pro- .duction'of polarization in die ectric partielse is securedeitherby a continuous or an interrupted convectiv'ely delivered charge in the manner hereinbefore andhereinafter described.

The pnncipaliobject of this "process of electrostaticmagnetlc separation is by means 'of the joint application of static electricity v five influence of the magnetic field or force so that the and the ma etic field of force, to increase the suscepti ilities'of certain particles hav-' ing feeblemagnetic properties to the attraccan be separated from others that have or-none -It has heretofore been discovered in the mofmagnetw separation that the shape or form of magnetic pole pieces has greatjinfluence in rendering certain particles susceptible to magnetic attraction that would not otherwise be afi'e'cted, and'in this manner it'has been possibleto separate out from a mass of particles sub- ,stances that would not respond to such a magnetic field of force as is produced by fiagilietic poles of ordinary construction.

e pole piece is rounded in form having approximatelythe same cross section; as the 4 opposite ole the neutral line would then be ,about mi way between the two poles. That is, if a particle of matter susceptible to magthese conditions the ma netic lines of force are greatly concentrate becomes supersaturated and the neutral line under these conditions, the other pole being of greater area, is very much nearer the larger ole. effect 0 static electricity acting in the manner as we have described has not yet been taken into account, and we will now consider in'what way the discharge of electricity in on the tip which In the above illustration, the

the current form from an ad'a'cent pointed terminal affects the result. en the mineral is fed to a'n'electrode which is also the opposite magnetic pole, thev elfect of the convective discharge acting directly,- not inductively, on the particles is to polarize them on the pole to which they are fed. It,

is evident that if the attractiveforce ofthe magnet1c pole on; to which the material is fed 1s actlng to attract such particles as possess magnetic properties that said particles 1 in which 1' is an electrode having a, sharp-v ened'of pointer terminal and 2'is an oppos ing electrode which in this instance is in the form of a roller or cylinder? which .byany suitable'means is adapted to be rotated :3

is a ho per in which the comminutedmate rialto separated into itsfconstituent ele-. ments is. laced and from which it is fed to the cylin er in any 's uitableinanner whichin this instance is a shaker pan which is vibrated by means of an eccentr c connected thereto by the-rod 6., The wlper 7 may be provided for removing adhermg particles 5 rain the cylinder and at a point upon its rear surface. I

By reference to Fig. 5 the manner of supporting said cylinder and adjacent magnets will be clearly understood where 8, 8 and-9 10 are magnets, the poles of the

magnets

8, 8 extending downward, as shown at 10 to form bearings for the journalsof the roller 2 on one of which is a belt pulley 1 1 senvingfor, imparting rotative power'to the. roller; The magnet 9 has the pole 12 extended inthe form of a thin edge and adjustably arranged in relation to the cylinder 2. In.

thisinstance the adjustment is accomplished bythe bolt 13 and slot 14 securing said magnet. to a cross beam 15 which also supports the magnets 8 in any suitable manner, and

which is insulated from the-framework 16 of the apparatus by means of the bolts 17 passing through insulated sleeves 18 in a manner well known in electrical constructions. The magnets are energized by a dynamo 19, the connections of which will be hereinafter described. The

electrodes

1 and 2 are served from a source of energy 20, which as before '3 stated may be of any character and which in this instance is an electrostatic generator, and the connections employed will also be hereinafter described. An interrupter 21 is shown together with a cone speed regulating mechanism 22 from which the belt 23 goes to a-nywsuitable source of power for giving motion to the interrupter. In the practice of the process covered that the same is facilitated to a material degree by producinga segregation of the. particles. at the-instant they .leave the hppper or shaker pan and duringtheir passage to the cylinder electrode. a This result we attain by placing a dielectric shield inadvance of the discharge point of the hopper and in close proximity to the surface of the cylinder, whereby the convectively delivered charge from the pointed electrodeis intercepted by said shield. such being the shield 24 adjustably mounted as shown. It is to be understood in this instance that the magnet 12 and shield 25 are in an elevated'or adjustedposition which gives the convectively delivered charge from electrode 1 free access to the shield 24 at the hopper.- The effect [of this shield 24 is that said charge imparts a +charge to the shield by the pointed electrode and induces a charge upon the-onposite side ofthe shield thus producing in 3 the particles back of the shield an inductive charge of like polarity on each particle which has a tendency to separate them one fromthe other and in which condition they fall upon the cylinder electrode, and the ma- 5 terial is thus presentedto said electrode in.

we have disa thin sheet-like form which facilitates the subsequent separating action of'the convectively delivered charges thereon.

1 25 is a dielectric shield adjustably mounti ed by'means of the

arms

26 and 27 and the bracket 28 extending to any fixed part of the apparatus whereby theproximity of the shield to' the cylinder electrode 2 and itsrelative. inclination may be determined to suit the conditions or character of material to be treated. I The action taking place caused by thepresence of this shield is somewhat similar to thatheretofore described. It is understood though not in a restrictive sense, that a portionof the convectively de livered charges from electrode 1 are 'couposite sideiof the shield,- and as the'electrode revolves the more weakly adhering-particles are releasedby the charge on the front. of the shield and they fall upon the shield 29. This shield 29 is adpistably supported in practically the same anner asth'e shield 25 and is constructed, liliEthe remaining shield, of hard rubber or of er dielectric material. But there is placed upon the upper surface of the'shield 29 a plate 30 of metal or other suitable conducting material whereby portions of the charge from the pointed electrode l .are neutralized or prevented from v acting through the body of the shield so as to affect material below the same. It will i be noticed, however, that'the extreme front edge of the shield 29 of dielectric material is not covered by .said plate so that the same electrical action takes place as that of the shields previously describ ed and here the charge from the pointed electrode produces an induced charge upon the opposite or under surface of the shield which byreason of the similar-polarity of the particles on the cylinder electrode has :a tendency to release those particles from the cylinder which were not released in the previous action above described. It will be noted that the plate 30 is connected to the ground, 'as shown at 31 which removes from f itjany. charge received'from the pointed'felectrode. The shields 32 and 33 although represented p as being made of dielectric material; practically serve as divisionyplates -it being understood that all of the'shields described extend longitudinally for practically the ,en-

no i p possible, howevei thatthe induced chargesreceive the various collections of separated particles.

Referring to Fig. 1 the various electrical connections shown therein will be described. From. the ole of the generator. there extends a circult wire to the interrupter '15 21 where the Wire iscut for the passage of the disks, and beyond the disks said wire is extended-to a point where it merges into the wire 36 leading to the pointed electrode 1. From the side of the 37 leads to the switch 38 y which it is connected to the wire 39 which is also severed for the passage of the interrupter disks therethrough and is afterward mer ed into the wire 36 leading to the pointed e ectrode. For the purpose" of cutting out the' inter-v rupter the branch 40 is provided having the sw1tch41 and mer 'ng intc the wire 36, and a second branc .42 having the switch 43 likewise merging into the 'wire 36 is provided so that by closing the switches 41 and ,43 a constant c ar e either or may be conducted to the e ectrode. The connection of the cylinder electrode with the source of supply 'ma be accomplished directly b means of t e-branch 44.having the switc 45 therein switch 110 being open, extending from the wire 35 to the journals 0% the cyli inder or to side of the generatorby openextends froni'the shaker ing switch 45 and closing switch 110. An-

other branch 46 having the switch 47 extends ."to. earth so that by opening the

switches

45 and 110 and closing the switch 47 the circuit may be grounded.- A line 48 an to the ground line of the cylinder in-ordbr. to prevent any charge bein conducted to the: elements .of the materia' the-hopper. The line-I35 from the I' side of the generator is also extended tofthe groundljby the branch 49' .providedwith the switch 50, while the side of "the generator-is provided with a similar branch 51 for the purpose, of ground- 1 ing that. side; of the machmeh A switch 52 is place'djinthis latter branch to prevent groundingythe{apparatus when the direct .fco'nnection ofthej cylinderelectrode with "the generator ise'mployedr v The lines 49 J and 51;beyond" the switches'50 and 52 are connected withfthe resistance. 53, the'switch 50 or 52 of the ground lines is adapted to connect either the line 49. or theline 51 with the; resistance so that the grounding 'i lefi'ectupon ither linemay be modified tomore-orless neutrali'zethe or charge, 5' suppllied to the pointed electrode.

e c rcuits for-the purpose of energizing enerator the wire that s the

magnets

8, 8 and 9 comprise a line 55 from one of the brushes to the

terminals

56 and 57 of the double. thro'wswitch, while the opposite brush is connected by*wire 58 to the remaining

terminals

59 and 60 of said switch, the operating handle be ng shown at 61. From the terminal 62 of the magnets, and the return line 64 extends therefrom back to thejswitch, as clearly shown. A resistance 65 is connected into the fields of -.the dynamo magnets for the usual purpose of regulating the strength of the current generated and of the magnetic fields of the magnets employed.

. It now remains to describe the construction of the interrupter 21. It consists of a pair'of disks 66 each of which are slotted as -at 67, Fig. 3, and by moving one disk upon the other the length of the o ening extending through both disks may be be the entire length o f'the slot or confined to a fractional part thereof. For example, at 68 the dotted linesrepresent the open portions of the slot of the rear disk which is covered by the solid portion of the other disk, w ereby the slot thus formed through both disks is representedby practically one half ad usted to switch, a line 63 extends to the spools of the of the length of the slot in each single disk.

' pass from the generator to the pointed electrode, while the solid portions of the, disks regulate the inactive intervals between the charges. The terminals of the circuit adja cent to the interrupter disks and at each side of the interrupter are in this instance represented as being round. If the terminals were-pointed the wave produced would be own in Fig. 4 by reason of the brush like nature of the charge from ointed electrode, but in tile use of the roun ed'ter" minals upon both sides of the interr ter the wave line shown in Fig. 7 is produce as these terminals serve a disruptive discharge instead of a brush discharge, and consequently produces the difierence in the wave as represented in the two figures referred to.

With eitherv thepointed or rounded elec trode at the interru ter the rise and fall of, the potential is sud en as represented by the vertical lines intersecting the horizontal "line a, Figs. 4 and 7 which represents zero potential. This sudden abrupt rise and .fall in potentiak' in the wave employed in our process, the charge alone, or a charge aloneor both, is essential to the most successful separation of certain materials, and

furthermore, it is essential to maintain for terminal at the interrupter the corners a'-b 1 are slightly rounded by reason of the brush form of the discharge in such terminal, but the potential is maintained from a tob. New by reference to Fig. 7, and by the use of round terminals as shown in Fig; 1, the rounded corners 411+?) are avoided and to that extent the potential is maintained longer' at a certain value without rising or falling. This is a diagrammatic representation of what is understood to occur in the use of terminals of different forms in connection with the interrupter in circuit. The disks in this particular instance are each provided with *three slots, while the terminals of the

lines

35 and 39 are arranged diametrically oppositeeach other, and the slots are so posltioned that by a proper adjustmentboth terminals are 0 posite slots at one and the same instant which serves to short circuit the current back to the enerator for a-brief instant of time which 1s one manner of using the process which possesses material advanta es under some conditions and character 0 material being operated on. The number of openingsor their equiv alent in the disks is a matter of preference.

- In fact, as illustrated in Fig. 8, a disk 69 is shown having a metallic lug 70 inserted in and passing therethroug of which plug there may be agreater or less number, as desired, so that in the rotation of this disk contact is made with metallic terminals of the circuit of the electrostatic generator 20, as shown, by wires 71 and 72'. Assuming that' there is but one plu in .the disk 69 and that the terminals 7 2 an 71 of the circuit of an electrostatic generator are placed in the path of that plug during the rotation of the disk, it will be seen that the wave produced bythis interrupter is that illustrated in Fig. 9,wherein a sudden rise and fall ofjpotential occurs and is maintained along the line a-b, and an exceedingly limited period of time exists between each rise and fall. By extending the. surface. ofthe plug to' lengthen the time ofcontact with the terminalsv 71 and 72, thus lengthening the time during which the current is shortcircuited back to the generator the intervals of timerepresented by the spaces between the. ver- ,ti cal".line is increased during which the one ofthe disks and having a tapered face charge is inactive.

The' means for. adjusting. the disks 66,

shown in Fig. 1, for the purpose ofregulat- .ing the length of the slot passing through both disks consists of a sleeve 73 fixed to and acotiperating movable sleeve 7 4 having a similar face, the latter sleeve being adapt- ,ed for longitudinal adjustment by means of arm 7 5 through which the threaded adjusting bolt 76 passes seated in the nut-77 supported by any suitable fixed part of the apparatus.

In Fig. 5 there is illustrated practically the same means for energizing the magnets 8. 8 and 9 as before described, and in addition thereto a modified arrangement of the elements for charging the pointed electrode together with amodi e d form of interrupter. Upon one of the journals of the cylinder. electrode 2 bears a brush contact 80 connected to a conducting wire 81 covered with insulation 82, nd carrying by means of a pivot 83 of e ectrical conducting material extending fronrthe bar 81 an adjustable con tact plate 84. 'A similar bar 85 and contact plate 86 on its pivot 87 with similar-insulation 88 is connected by wire 89 withthe pointed electrode 1. A disk 90 is mounted upon the shaft 91 which may be rotated by any suitable means, and upon one side of the disk is an annular electrical conducting strip 92 from which project in this instance three wiping contact arms 93. Upon an op- 'posite side of said disk is a similar. annular strip,.as statedfprovided with three wiping contact arms 94-. The adjustable contact plates 84 and .86 are curved, as shown, to conform to the path of the ends of the contact arms 93 and 94: and each is capable of retaining an adjustment upon itsplvot 87 whereby the time of contact of any of the. arms 93 or '94 may be'predetermined and varied from a contact .coveringthe entire length of said plate or to practically any de sired distance diagonally across said plate determined by its inclination from-averticalposition when, the disk rotates in a vertical plane, as shown in Fig. 6. The-dotted lines 95in Fig. 10 clearly indicate the length of contact of the arms 93 or 94'on either side of the disk. A'brush 96bears con-v I tinual'ly'upon one of the electrical conduct ing strips 92 and'is connected by wire 97 -to one pole of an electrostatic generator,

and-another brush 98 contacts the opposite conducting stripthrough the wire 99 withthe opposite poleof the generator. The function of this form of'interrupter is to supply a charge to the ointed electrode and to reduce the potentia of bothv electrodes tozero, and to" accomplish this, with ex needing rapidity and accuracy and w1thout:

any perceptible intervals of lapsed time betwcenv the alternations. These objects are secured in theyfollowing manner. Assuming a current from the pole of the generator passing through thewire 99 and the brush 98 to the annular plate on theunderside of the disk, the. current would follow the plate until it reached the lower arm 94 at the left. Assuming themext adjacent arm 93 to. be in contact. with, the plate 84, and

I that therefore both

arms

93 and 9 Pare in contact with said late, then in consequence of this contact of th arms with the plate,

the current would follow the plate 84, upper arm 93, contact plate 92, brush 96 and the wire 97 back toe the generator at its pole. In other words, the entire charge of the generator is short circuited back to it from the cylinder electrode 2 for an exceedingly brief instant of time which would be occupied in the passage of arm 94 from plate 83 after arm 93 had contacted "therewith. The same operation takes place at the other side of the mterrupter with relation to the pointed electrode and consequently thereis a sudden rise and fall of potential in this instance involvin both polarities above and below the zero%ine 0. I a

The construction of interrupter shown in Fi 8 is, as hereinbefore described, but it on remains to say-that by the use of such an interrupter the same results with a round electrode 100 substituted for the pointed electrode 1 can be produced in so far as brin ing both electrodes to zero potential certalnly and suddenly is concerned and that by-short either by the reduction, existence or polal ization by di erent wave forms in the convectiyely delivered charges, and different conditions of strength in the magnetic field.

In the production of an alternating charge 1n the magnetic field switches 41, 43, and

52 are open, while the switch 47 is closed to connect the cylinder electrode to the ground. The interrupter 21 is rotated at a desired speed regulated by the cone pulley connec tion tothe source of power, when the open- -ing 67 is opposite the terminals of the line 35 a charge is given to the pointed electrode 1, the potential of which then rises and is maintained as represented in the diagram in Fig; 4 along the line a-?) with the corners slightly rounded. l/Vhen-in the rotation of the interrupter disks the opening 67 is in alinement with the wire 39 and its extension there is an immediate sudden drop of potential to below the 0 line when p a polarity is maintained as at a Z) in said diagram so that we have produced and maintained an alternation of and poi larity. In the diagram in Fig. 4 the corners are slightly rounded and it would only require an enlargement of the terminals of the

wires

39 and 35 to produce corners more nearly ap roaching the square at the pointsmentione \Vhen the terminals are intercepted byv the solid portions of the disks of the interrupter, the density, of the charge 111- ocreases upon the terminals, and portions of the slots and terminals'are opposite each other, the full charge passes instantly and the potential falls practically to zero.

To apply inthe magnetic field convectively delivered charges to the cylinder electrode which shall be grounded, said current being delivered from the pointed electrode 1, switches43, 52 and 47 are closed, and 45 and 110 open. In this instance we will deliver plus charges" from V the electrostatic generator 20 through the

lines

35, 42, switch 4,3 and line 36 to. the electrode 1 and through the magnetic field to the electrode 2 and from thence by the line-44 to the ground. In this instance 'it will be noted that the interrupter is cut out of circuit, the switch 41 being open nocurrent can pass in that direc tion. ".lhe'current produced in this instance would be represented by .a straight line, it I being of polarity. A similar arrangement. closing the switch 41 on the line and leaving the switch 43 open on the side of the machine would give us a constant current. In each of these instances, when delivering a charge to the pointed electrode the side of the machine should be grounded byclosing the switch 52, and in delivering a charge to the pointed electrode the side should be grounded by closing the switch 50. It is understood that the distinction between a convectively delivered charge and a current is that the former passes through a gaseous gap between adjacent terminals while the latter being the same charge, when upon or directed by a suitable solid conductor, is or becomes electricity in the current form, if said conductor" has the function of returning that electricity either to the eartlror back to the generator thereof.

.In producing an interrupted current switches 41 and'43 are open and the inter rupter rotated, switches 47 and 52 are closed -17 to ground the cylinder electrode and 52 to ground the pole'of the generator. This gives us an interrupted current of polarity, the wave of which is illustrated in Fig.10.

To give uninterrupted current of ''polarity switch 47 is closed .and either switch 45 or switch 50 is closed to ground .the pole of the generator and the switch 38 is closed onthe side of the generator and the switch 52, the ground line of the pole of the generator, is left open. In this condition the wave is represented in full lines in Fig. 11. v c

The charges supplied to the pointedelectrode may be varied by employing the resistance 53. For example, it it be desired to have a full strength charge in an alternating current, and a weaker then switch 52 is thrown into contact. with one of the posts of theresista'nc'e 53 to cfi'ect a greater or less diminution of the whereby there will be discharged from the pointed electrodc'into and through the magnetic field an alternating current whose is of greater strength thanits as indicated by dotted lines Fig. 11 representing the wave produced on the "line. I

Togive a constant charge of one polarity intermittently modified by a charge of the opposite polarity we close the switch 45 on the side of the generator thereby directly connecting the cylinder electrode 2 with the generator, the grounding switch 47 being switches 50. 110). and 52 opened. Now, a charge will be delivered both-to the elec-' trode 1 and to the electrode 2; and interleft open, then switch 43 is closed and'switch 41 is opened and switch 38 closed and mittently as the opening '67 ot the interrupter al ines with the wire 39 a charge will .be delivered to the pointed electrode. Under this condition we have a constant charge of one polarity on one electrode represented by the straight linein the diagram of the wave shown inl ig., 12. and we also have a succession of charges of the op posite polarity (minus) which impinge and are active as illustrated in sald Fig. 12 at thepoints d d and are inactive at the points 40 all of these varied wave eflects by the application of our prpcess, still further modificatlons 1n said waves and their eltectupon .the mate rial being treated is provided for in the regulation of the strength of and of the polarity of the magnetictield used in conjunction therewith.

In this invention it is to be understood that an electrostatic 'convectively delivered charge. from. an electrode having a sharpened termination produces an even flow of through said air, or gaseous gap momencurrent to an opposing electrode as uninter ruptedly as that produced by a galvanic current passing over a conductor, while a rounded electrode can be made to deliver to an opposite electrode intermittent charges of potential, the inter-missions being caused by the accumulation of a charge of such pressure as becomes greater than the intervening air can withstand.- The air, which is simply a dielectric, is.broken down and a spark passes from one electrode to the other,

from 'the pointed electrode.

It is to be understood that in producing tarily lowering the potential, so that when a slot opening in the disk is o posite one or both of the rounded term'ina aseries of discharges takes place in rapid succession, while if pointed terminals are used the transfer of potential takes place with an even flow of convectively delivered charges.

\Vhile a discharge of static electricity from a sharp point acts upon a dielectrlc particle in a manner similar to an interrupted char e trom the rounded electrgdewhose potentia s are characterized by either a rapid rise or a rapidrtall, ordioth, 1n the potential supplied them. we disclose'means for causing violent fluctuations in the charge delivered To illustrate the facts clearly, the electrostatic convectively delivered charge flowing from a sharp pointed electrode to one to which the mate-' the rest by the fact. that in the time in which the charge is'given one set is polarized while the other-is not. The rounded terminals do the same with intermittent charges with, however, this ditterence; the longer the time ofthe charge-delivered, the less will be the polarization owing to the fact that the particles acquire the-same potential as the electrode and would be repelled. Therefore with rounded electrodes the'charg'e must be accurately timed so that the particles will neyer become fully charged thus inalntaining them at a constant dlfi'erenceof poten tial from that of the conveyer electrode to prevent repulsion; On the other hand, the longer the duration of application of the 0on vectively delivered charges from. the pointed electrode the greater will be the polarization of the particles up to'the maximum of their capacity, but never reaching a repelling'potential. I '1 The material to be separated is in granular or pulverized form and is placed in the hopper 3 and is ted therefrom bythe vibrating shaker pan 4 onto the electrode 2. The

hopper 3 and shaker pan 4; bein grounded. by line 48, and the shields 24 and 25 further act to protect the material in the hopper and pan from the action of the pointed electrode so that the material falls upon the electrode 2 andis carried by it into the fields of the magnct'12 and pointed'electrode 1.

When in these fields those particles having feeble magnetic properties that are alsodicapacity but being also feeblymagnetic are carried by the rotative'movement of the electrode 2 across theneutral line 'into the field of magnet 12 by reason ofthe concentrated lines of force thereof. Now comes into action the shield which, is polarized at itstip by the action of the convective current from the points of the electrode 1, acts more strongly upon these particles having no or feeble dielectric capacity and attracts them to prevent their contacting with pole 1'2 and directs them onto shield 30. These particles are eventually delivered from the shield into the first receptacle 34. Some of the particles that still adhere to electrode 2 are carried by it into proximity with shield 29 where some particles are thrown by the rotation -o the electrode 12 upon said shield 29 and 1nto the second receptacle 34, While others of such particles are polarized by the tip of said shield so'as to release them from electrode 2 when they fall intothe third re ceptacle 34;. The particles that still adhere to electrode 2 are removed by the wiper roll 7, the. shield 33 acting simply mechanically to divide said particles into two bodies depending I'or division only upon the shorter or longer duration of adherence to electrode In some cases the magnetic action predominates and in othersthe static action predominates depending upon the responsiveness of the particles to one or the other force or effort. In the present invention the feebly magnetic particles are rendered,

by the. convective static charge or effort,

more responsive to the magnetic. force or efi fort. It'1s also not essential forsuccessful operation that these forces act in opposing.-

direction. 7

Having described our invention and several forms of apparatus in which it may be embodied for practical use, what we claim and desire to secure by Letters Patent is 1. The process of treating the particles of a mass for separation which consists insubjecting the same to the action of an electrostatic charge convectively delivered upon said particles and regulated to produce and maintain a polarity upon dielectric particles opposite to that of one electrode while in a magnetic field, and separately collecting the separated particles.

2. The process oftreating particles of a" mass forseparation which consists in producing and maintaining by a convectively delivered electrostatic charge a difi'erence of potential between the particles of material and an-electrode while in amagnetic field, and separately collecting the separated, particles.

3. The process of separating the particles of a mass which consists in producing and maintaining a diflerence of potential be tween the particles of the material and an electrode while in a magnetic field, subsequently depolarizing said particles to release them from said electrode, and separately .collecting ,the separated particles.

4. The process of separating particles of a mass which consists in subjecting the same to an interrupted static charge of one polarity while in a magnetic-field, and separately collecting the separated particles.

5. The process of separating particles of a mass which consists in subject ng the particles to an interrupted charge of one polarity and in modifying the strength of said charge while the particles are in a magnetic field, and separately collecting the separated particles.

6. The process of separating'particles of a mass which consists in subjecting the particles to the action of'a magnetic field and to a convectively delivered static chargev of one polarity which polarity iscontinuous and to a convectively delivered static char e I 8. In a process of separating comminuted 1 materials consisting in separating such materials by the action of combined static and 'magnetic fields, in reversing the polarities of the magnetic poles relative to the-polarity of the static field, and separately collecting the separated particles. a

9. The process of separating comminuted materials consisting in separating such materials by the action of combined static and magnetic fields, in reversing the polarities of said. static field to adapt the polarities to the particular material being separated, and separately collecting the separated particles.

10. In a process of separating comminuted material consisting in submitting it to a combined static and magnetic field, electrically shielding the material from a portion of said static field, and separately collecting the separated particles.

11. In a process of separating comminuted -material consisting in subjecting the madients of mixed comminuted material which consists in subjecting the material simultaneously to magnetic attraction exerted in. one direction and. a convectivelydelivered static charge exerted in another" direction, the magnetic attraction dominating the electrostatic convectivexeflort in respect to material inherently responsive to both forces,

and separately collecting the separated particles.

14. The method of separating the ingredients of mixeducomminuted material, which consists in subjecting the material simulta-' neously to magnetic attraction exerted in one direction and to a convectively delivered static charge acting in another direction in respect to material inherently responsive to both forces, and separately collecting the separated particles. y

'15. The method of separating ingredients of'mixed comminuted material Which consists in subjecting the material simultaneously to magnetic attraction and a static charge delivered convectively to the material, said material being inherently responsive to both forces, and separately collecting the separated particles. I

r 16. The method v f separating ingredients of mixed comminuted material-Which consists in subjecting the material simultaneously to magnetic attraction and to a static charge delivered convectively to the material, regulating the effective potential of said charge relative to the intensity of the magnetic attraction, and separ sists in subjectingthe material sim "ously to magnetic attraction and to a c the period of duration of time of applicaarately collecting the separated separated particles.

17. .The method of separating of mixed comminuted material W vectively delivered static charge, regulatin tion of said charge to act selectively on the susceptible particles of the material and sepparticles. 18. The process of treating particles of a mass for separation, consisting in subjecting the same to an electrostatic charge regulated to produce and maintain upon the nonconducting particles of the mass a polarity opposite to that of a separating electrode, passing said mass through a magnetic field, and separately collecting the separated particles. 19. The process of treating particles of a mass for separation consisting in passing said mass through a magnetic field and producing and maintaining -upon particles of the mass in the magnetic field a potential differing from that of an electrode, and separately collecting the separated particles.

In testimony whereof We affix our signatures in presence of two Witnesses.

. HENRY M. SUTTON.

WALTER L. STEELE. EDWIN G. STEELE. Witnesses: