US2586574A - High-frequency jig - Google Patents

Description

Feb. 19, 1952 F. P. SMITH HIGH-FREQUENCY JIG Filed May 10, 1946 2 SHEETSSHEET l /N\/EN7'OE,' FEANK P. SMITH,

Feb. 19, 1952 F. P. SMITH 2,586,574

HIGH-FREQUENCY JIG Filed May 10, 1946 2 SHEETSSHEET 2 Patented Feb. 19, 1952 me's'ne assignmeiits,,,to Thef .Ietfrey}Manufac'- turin'g com any, Co1umbus},Ohi0,I alcorpo'r'ae ApplicationMav 10,1946, seminar-668,845":

This invention relates to] ,a' high vfreqiiencyijig;

Anlobject' of the invention is .to provide an. iiiip'rovedfldevice. of the above. mentioned'type which will treat granular mineral niateriali par? ticularly. of. small sizes, to efiect'al separation ac: cor-ding; to specific gravity;

A ,f urther object of theinv'ention" is to provide-"l an improved device of I the above mentioned type;

with a, dam and 1 seal ty'pe dffldraw in" which. me chan'icall means or mechanism, opeiable'piridependently' of 'thevibration of the material, .is"pr'o-. vided1 ,to.efiect a controlled removal 'of-'the":-con,-. centra'tes or heav'y gravity material.

A; further-object. oi the invention is to' provide a jig orcla'ssifi'er with automatic means to re? movefconcentrates so as to maintainla predeter mined depth of concentrate stratum'or hed,.pa'i'.-

ticularly involving aed'a nia'nd seal type of'draw; andfwhich, in the preferred embodiment .of my invention, also includes a skimmingldevicesuch as a paddle. wheel for removing concentrates from. a concentrates cell.

Alfurtheriobj'ect of the invention isto provide an improved" jig in which fine sizes'of graniilar' mineral. materials are separated. according to specific gravity] byf .vibi'ationflwhich is applied" to. the diaphragm, preferably'fo'n the, bottom of the: container which supports said bed of materials" in -.a'. pulp and in which high. frequency vibration is applied preferably at lwa'inpliti1de.

Other 1 objects of, the; invention willll appear? hereinafter, the novel featuresla'nd combinations being setvtfdrth in. the" a pended claims:

In the accompanying drawingsi Fig 1 isa front elevational view of .apparatus incorporating rtheifeatures' of -my} invention; Fig.1 2-. is a side view oi sa'id",apparatus; with parts shown in section; I r Fig: 3 is aplan view'of the apparatus; with parts omitted: and

Fig, 4f iSjaLWiringjdiaIgram' of one -,rorm 1 of electrical circuit which. may. be emplcy'edito control? theskimmer mechanism: v

ig 1 or classifier of my' jinventiori includes atstationary deck; containenori tank III which;

provides compartment 1 or receptacle-for re ceiv t il' ranular mineral which to 1 be separated. ifitd two: groups of. particles"according' ta specific gravityif Theapparatusisdesigned par ticu'la'rly for treating" a" relatively iwide" range for" small size particles; The1appg'airatil-$3.ioi'ieirample; is designed to treat a: size range f'roiiififiito 3'25 mesh; As ai'specific illustration ofi'oneltypeioffi fully treated iron ore of size range from \80 mesh-- to 270-.mesh with a-highorder of -efliciency,- having; produced-arvery pure concentrate of iron/oreandgangue-vor silicon refuse containing very little ore.- Ashotbed may also be used.

It is; of course, evident that. thejigt mayytreati other. materials I than---.iron-;:ore, as it may be used for variousoresnand furthermore :may in some instances--be employedrto separate coal from its ref-use? in; which case-:the high: gravity: material will berthe refuse; which the 1 reverse or the condition'whenzore is-treated; In the subsequent 1 description I shall refer morespecifically' toiron oreas theillustratedmaterial; which. is being treated;

The fine' ironaore to: beaseparated; from: its

gang'ue; particularly silicon; is fed to the deck. III- with: an appreciable-quantity of Waterso as:

to provide an ore pulpiwhich wi1l havea normal.

'- level in the container or compartment: IIl,-.. as

indicatedeatzll,iniFig; 2=;of the'drawings; The" pulp will flow: freely down. an inclined feed chute I2- intoithe main. part of 1 the compartment It; The container; I0 is provided with a false-bottom =I31-in=the form of a screen which is held downb'y appropriate hold-down means i I 4 in co-operation with-a as supporting: egg'I-cr'ate partition: which helps distribute then-water through the perfdrah tion inthe false bottomscreenl3; In one-"successful form of the invention-the screen 'or'fals'e bottom I3 rwas a inultiporerubber screen. It'

preferably-a very finekmesh screen and in treat" ing rlthe size range of: -"-2'70 mesh -I have successfully used screens I3 with a mesh varying from' The e'gg crate partitions I5 are containedin a h'lltchi compartment I 6 which is for rned as a part of the container' I D and belowthes'creeri I3; Hutch 'compartment l I provided'with'a plurality: of longitudinally extending water feed pipes I I by which a' relati-vely 'sr'nall am'ountof water introduced into *the -various cellsof the egg cratepai tition l 5, which walt ei flowsu wardly through the screen plate" l3 int'o the pulp Com partment- H'I-L- The h'utch compartment I6 and through itthe container- I 0' is supported" on" 1 a stationary 1 frame' l 82 The central bottommo'rtion of the liutch corh partment la is in; thefon'n of a diaphragm I 9' "whichis attached to'the adjacent-bottom portion by inean's f, aij rubberri'ng 20 which provides. a V. fluid-tight bottom for? saidighiitch" compartment I 6" but; which", allbws; reciprocation ,,of";'th"e1l; d

5!?wardlj7; Thisrectiliiiear' vibrators motion is delivered to the diaphragm l9 by a vibratory electro-magnetic motor 2i, the armature head 22 of which is rigidly attached to said diaphragm IS. The motor 2| preferably follows the structure shown in the patent to James A. Flint, No. 2,094,698, dated October 5, 1937, for a Device for Packing Materials.

Adjacent the discharge side of the container I9, which is to the right, as viewed in Figs. 2 and 3, there is a weir 23 over which the gangue or refuse flows, being guided therefrom by gangue discharge chute 24. Preferably located along the longitudinal center of and within the container or compartment H3 and provided by a substantially U-shaped upstanding wall, plate or partition 25 is a concentrate or high gravity material cell or compartment 26. As is clearly illustrated, particularly in Figs. 2 and 3 of the drawings, the plate 25 extends both above and below the normal pulp level H, and the bottom edge thereof is close to but slightly above the false bottom or screen |3.

As hereinafter described more completely, the bottomedge of the plate 25 also extends slightly below the level of the bed of concentrates or high gravity material which forms in the bottom of the compartment under the classifying or jigging action which takes place. The depth of a typical concentrates bed is illustrated at 2? in Fig. 2 of the drawings. A weir 28 having preferably the same height as the weir 23 is provided for the concentrates cell or compartment 26 and the concentrates which flow over the weir 23 are received by a trough 29.

It is evident from the above description that the cell 26 formed by the plate or partition25 provides what is, in effect, a dam and seal concentrates draw. I have found, however, that the dam and seal type of concentrates draw may have its efficiency very vastly improved so as to prevent all land-sliding, which such draws tend to produce, by providing a skimmerv means or other functional equivalent mechanism for removing concentrates from the concentrates cell or compartment 26. In the illustrated form of mechanism for thus removing concentrates and causing them to flow over the weir 28 I provide skimming mechanism in the form of a skimming paddle wheel 30 which is preferably continuously operating at a variable speed, as hereinafter described more completely, the wheel 30 being preferably rotated in a counter-clockwise direction, as viewed in Fig. 2 of the drawings, so as to skim the top of the concentrates from the cell 26and to cause it to flow over the weir 28 into the trough 29. Within the scope of my invention, in some of its broader aspects, other means may be employed to remove concentrates from the cell 26 preferably by a positive and continuous action.

Mechanism for controlling the rate of withdrawal of concentrates from the cell 26 will now be described. A small electric motor 3| (see Fig. 3) is provided to drive the shaft of the paddle wheel 30 at a controllable rate which is varied so as to maintain the concentrates bed 21 at approximately a predetermined depth, or, stated or plate 25. A small amount of air is then continuously forced through the pipe 33 from a source of air, indicated in Fig. l of the drawings, which is delivered to pipe 33 by way of pipe 34 and flask bubble indicator 35.

Branching from the pipe 33 is a manometer pipe 36 leading to manometer 31 which contains a saline solution 38. At the top of the manometer 31 is a platinum contacting wire 39 and at the bottom thereof is another conductor 40. It is obvious that the manometer 31 will measure the density of the pulp at the bottom of the pipe 33 and whenever this density reaches a predetermined amount the saline solution 38 will contact the platinum conductor 39, connecting it with conductor 40. This is in effect, therefore, a manometertype switch. Whenever the density of the pulp at the bottom-of the pipe 33 falls below a June 15, 1946, now Patent No. 2,461,131, granted pulp bed II by controlling the rate of removal of said concentrates from cell 26.

The particular electrical circuit, shown in Fig. 4, which has been found to be best suited for controlling the motor 3 I, is the invention of Francis C. Todd and is disclosed in his application Serial No. 676,883, entitled Electrical Circuit, filed February 8, 1949.

The electrical circuit of said Fig. 4 includes a main source of alternating current 4| which sup-' plies a full-wave rectifier 42 and associated filter 3 43,'the output of which is delivered to a high resistance potentiometer 44.

Conductors 4| also supply split fields 45 of a Merkle-Karif type series alternating current motor 3| which has a resistor 46 connected in series with said fields.

another way, the concentrates are removed at a variable rate so that the density of the pulp at a predetermined level in the pulp bed will tend to remain approximately constant. To this end I provide a density prober 32 which in its general characteristics is of well known construction and includes one or more pipes 33 which extend downwardly into the bed [I with the bottom of the pipe 33 at a predetermined position, preferably slightly above the bottom of the partition The rate of rotation of the motor 3| is controlled by placing a variable impedance in series with the armature thereof, this variable impedance being in the form of a secondary of a transformer 41. The current delivered to said secondary of the transformer is controlled by controlling the grid voltage on a pair of vacuum tubes 48 connected across the terminals of the primary of said transformer 41, as clearly illustrated in Fig. 4 of the drawings.

To produce this variable and gradually changing voltage on the grids of tubes 48 I provide a double tube 49, the left hand portion of which derives cathode-anode voltage from a variable tap on the potentiometer 44 over an obvious circuit which includes resistor 50 in series with the cathode. This resistor 53 may have a value, for example, of approximately 500,000 ohms.

When the monometer switch 37 is open, indicatin the pulp density is below the normal deby way of resistors 5| and 52. I ditions the current flow through resistor 50, which portion of tube 43, will be a maximum.

The voltage thus developed across resistor issu'pplied through an obvious circuit, including r d hift i9... ..fi9a ti e. ee g l e e iiii.

attach whi'ch includesia relatively -large condenser 55 and a relatively high ohi'n resistor 56 in parallel.

Asan illustratio'n'of workable values, resistor 53-inay have 4,000,000 ohmsand resistor 55 may have 5,000,000.. Obviously when there is voltage across resistor 50 because of a cathode-anode currentflow through the left-hand portion of tube 49, the condenser 55 will tend to charge and this charge will build up at a relatively slow rate so long as said voltage persists. On the other hand, assoon" as this charging voltage disappears from resistor 50, the charge on condenser 55 will gradually decrease since it will discharge through the resistor 56 in parallel with the two resistors 56 and. 53 in series. Because of this fact the discharge rate of the condenser 55 will be greater than'its charging rate'and this is desirable because, :as hereinafter described, the speed of the motor 3! and thus the rate of withdrawal of concentrates is directly proportional to the charge oncondenser 55 and it is desired to increase the speed of said motor 3! ate. faster rate than it decreases.

When the manometer switch 31 closes its contacts in response to a production of a predetermined density of the pulp at the selective. position, a negative charge is put on the grid of the left-hand portion of tube 49 since resistor 5| is thus connected directly across the portion of potentiometer 44 which is being used. This closing of manometer switch 31 willalso effectively connect-grid condenser 58 and grid resistor 58 in par-'- allel with the megohm resistor 52.

It is thus seen that resistor 50 is a follow resistor in that the voltage drop across it is either a. maximum or a minimum, depending upon whether manometer switch 31 is open or closed.

Theright-hand side of tube 49 includes fol-- lower resistor 59 connected in its cathode circuit, and the current flow through this resistor 55 and thus the voltage drop across it is directly proportional'to the charge which exists on the time control circuit 54, or, in other words, the charge on a variable portion of the voltage drop thereacross is applied to the grids of the control vacuum tubes 48--over-an obvious circuit whereby the current flow inthe transformer 41 is directly proportionalto this voltage drop across-said resistor 59 which in turn is directly proportional to the charge on condenser 55.

It is thus evident opened and closed condition of the manometer switchel there is a'gradual change produced in the speed of the motor 3|. Furthermore it is to be noted that the time'circuit 54 will automatically continue increasingthe speed of the motor 3| or decreasing it until a-changed condition is produced by the skimming mechanism 3 3 to change the switch from open to closed condition or vice versa. Under suchconditions there will be a continuous removal of the concentrates and the rate of removal will vary from time to time. In fact it will vary almost continuously, but the average or mean rate will be such as to maintain that by controlling the asubstantially constant depth of-goncentrates.

or-,=in'other words; a substantially constant densityof the pulp'bed at a pre-selected' position.-

Thiscontinual hunting of the skimming type,

concentrates removing mechanism has heen found to'be very efficient in-operationbecause it prevents undesirable building up of density of concentrates with a sudden removal thereof-or land sliding which has been a problem generally present in dam and seal draw types of concentrates or heavy gravity discharge mechanisms heretofore known.

In the operation of the device, toeffect agrav ity separation of material, such as very-fine iron ore, the iron ore with-a-liberal-supplyof water'is fed into the container l0 and forms apulp bed, as indicated byth'e line I l in Fig. 2 of the drawings. This bed is subjected to the combined action of 'upwardlyflowing current of water orli-quid through the screen l3 and electrical vibration.v preferably rectilinear and. upward, provided by the diaphragm l9, which is delivered by themetor 2|. This vibration is preferably relatively small so as to give mobility to the bed butb'eing. insufficient to produc'eany packing action-which is found to occur if the amplitude is too high.

.As anillustration of one practical frequency of jigging employed, for materials of a size range,

of mesh to 270'mesh of iron ore,I have onerated successfully with the frequency of vibrations at 3600 vibrationsperminute at an amplitude of 1/64 of an inch. Experiments indicate that if the frequency is increased; for example, tovzco vibrations per minute, the amplitude maybe-further decreased, for example, cut in half or made /528 of an inch. Furthermore, tests indicate that if the sizerange of material =isdecreased the amplitude may also be decreased. Furthermore, the water supplied'in the hutch'lfi is preferably relatively small. In the-example given it maybe approximately two gallons per minute. If more water is employed in the hutch the amplitude may also be decreased.

If the frequency is appreciably decreasedthe amplitude maybe proportionally increased, :but I have found that the apparatus is particularly adapted for relatively high frequency vibration and by this I mean a frequency in excess of 1000 vibrations per minute. Actual tests have been conducted with vibrations as low as 1800 per minute at which an amplitude of 5% of an men was found satisfactory on fine material of the size range above specified.

The tests also indicate that for large'r'sizes, for example, asize range iromlO mesh'to 65 mesh, as an illustration, the amplitude may be increased over that amplitude for smaller "size'materi'als. Furthermore the hutch water is. preferably increased for larger sizes.

The bed of materialundergoing' jigging or'classification tends to form concentrates in the bot tom of the bed or, in otherwords, in the'bottom stratum of thebed of "material, which stratum of concentrates is supported by the screen l3 and the depth of these concentrates is preferably substantially as indicated at 21 in Fig. 2 of. the drawings, or, in other words, above the'bottom; of the wall 25 forming the 'concentrates'cell l fiforfinother words," which forms the dam'and-seal draw, As the concentrates are skimmed off or otherwise removed from the concentratescell, for example.

as they are skimmed off by the-skirninerim the level of thepulp-or-liqllid-in the cell 26Wi11,of

centrates under the lower "edge of; partition-'25 and into the 'concentrates'cell 26. Thiaconcem; trates pulp in the concentrates cell 2 B will be:

7 quite fluid and mobile and thus the skimmer 30 will continuously remove the concentrates and deliver it over the weir 28 to the concentrates chute 29.

I have found in practice that the efficiency of the dam and seal draw as here employed has been very greatly increased by the positive removal of the concentrates from the concentrates cell 26 because, in the absence of such positive removing mechanism, such as the wheel 30, there is a tendency for the dam and seal draw to operate erratically. That is, it tends to build up a predetermined head and then slough oil or land slide, with a consequent discharge of an appreciable amount of gangue or low gravity refuse with the concentrates.

By the positive removal of said concentrates, particularly at a controllable rate so as to maintain a predetermined concentrates bed 21, this erratic operation has been eliminated completely, with very great improvement in the overall efficiency of the device for continuously separating two materials of different specific gravity, such as iron ore from its gangue.

Obviously those skilled in the art may make various changes in the details and arrangement of parts without departing from the spirit and scope of the invention as defined by the claims hereto appended, and I therefore wish not to be restricted to the precise construction herein disclosed.

Having thus described and shown an embodiment of my invention, what I desire to secure by Letters Patent of the United States is:

1. A vibratory classifier including a container adapted to receive fine mixed mineral materials and to separate the materials of different specific gravity, said container having a perforate false bottom constructed to support a bed of material undergoing separation and to support the concentrates developed, means for producing a flow of liquid upwardly through said false bottom, means applying high frequency rectilinear and vertically upward vibration to the liquid, said vibration having a frequency of at least 1000 vibrations per minute, all whereby a stratum of high gravity concentrates is formed on said false bottom, means providing a concentrates cell having a wall a lower edge of which is spaced above and near said false bottom whereby said edge is in the lower part of said bed of material and extends below the normal top of said stratum of concentrates and the high gravity material in said container is forced to flow under said wall by hydraulic pressure of material in said container, and skimming means for skimming the top oif the concentrates in said concentrates cell, said skimming means being positioned entirely above said false bottom and operating to skim the top only of said concentrates in said concentrates cell.

2. A high frequency jig including a stationary container adapted to receive a bed of mixed fine particle minerals to be separated according to specific gravity, means for applying vibration to said bed at a frequency in excess of 1000 vibrations per minute while said container remains substantially stationary, a dam forming a concentrates cell and having a lower edge adjacent the bottom of said bed below which the high gravity particles in said container is forced to flow into said concentrates cell, and skimming means including a motor driven paddle wheel positioned entirely above the bottom of said bed and operable for skimming concentrates only from the top of said cell.

3. A high frequency jig including a container adapted to receive a bed of mixed fine particle minerals to be separated according to specific gravity, means for applying vibration to said bed at a frequency in excess of 1000 vibrations per minute. a dam forming a concentrates cell and having a lower edge adjacent the bottom of said bed below which the high gravity particles in said container may flow into said concentrates cell, and skimming means located within said concentrates cell and operable to skim concentrates only from the top of said cell.

4. A high frequency jig including a container adapted to receive a bed of mixed fine particle minerals to be separated according to specific gravity, means for applying vibration to said bed, a dam forming a concentrates cell in said container and having a lower edge adjacent the bottom of said bed below which the high gravity particles in said container may flow into said concentrates cell, and skimming means located within said concentrates cell and operable to skim concentrates only from the top of said cell.

5. A classifier including a container providing a classifying compartment, a dam and seal draw providing a concentrates cell, and continuously operating mechanical skimming means located in the top of said concentrates cell and operable to skim only the top oil material in said concentrates cell.

6. A classifier including a container providing a classifying compartment, a dam and seal draw providing a concentrates cell, and mechanical skimming means for skimming only the top off material in said concentrates cell.

7. A classifier including a classifying compartment, a dam and seal draw providing a high gravity cell, and continuously rotating paddle wheel skimming means operable to skim only the top off the material in the high gravity cell.

8. A classifier including a classifying compartment, a dam and seal draw providing a high gravity cell, and continuously rotating paddle wheel skimming means operable to skim only the top off the material in the high gravity cell, said means including mechanism operable at a vari able rate determined by the density of pulp adjacent the bottom of said classifying compartment.

9. A classifier including a classifying compartment, a dam and seal draw providing a high gravity cell, and positively acting mechanical skimming means operable to skim off only the top of the material in the high gravity'cell, said means including mechanism operable at a vari able rate determined by the density of pulp adjacent the bottom of said classifying compartment.

10. A high frequency jig including a classifying compartment, a screen providing a material pulp bed supporting bottom, means for delivering liquid to flow upwardly through said screen including a hutch compartment below said screen,

a diaphragm in said hutch compartment, means;

for vibrating said diaphragm relative to said classifying compartment, said means including a vibratory motor operable at a high frequency of at least 1000 vibrations per minute, a dam and seal draw providing a concentrates cell including a wall having its lower edge slightly above said screen, mechanical skimming means including a rotating paddle wheel for skimming only the top REFERENCES CITED The following references are of record in the file of this patent: I

UNITED STATES PATENTS Number Name Date 217,064 Clark July 1, 1879 Number 10 Name Date Caetani June 1, 1909 Elmore July 11, 1911 Shields Sept. 16, 1913 Daman Nov. 18, 1924 Fraser July 9, 1935 Haworth Jan. 28, 1936 Bird Oct. 11, 1938 Krant Feb. 3, 1942 Chisholm Mar. 2, 1943

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