US1392401A - Method and apparatus for classifying materials - Google Patents

Description

H. M. AND T. M. CHANCE.

METHOD AND APPARATUS FOR CLASSIFYI'NG MATERIALS.

' APPLICATION FI LED JULY 8.1918.

1,392,401 Patented Oct. A 4, 1921.

3 SHEETSSHEET l.

'IIIIIIIJ'IAI Inventors. #LMMT 7k CL Mex H. M. AND T. M. CHANCE.

METHOD AND APPARATUS FOR CLASSIFYING MATERIALS. APPLICATION HLED-JULY 8,191?- 1,392,401, iv Patented Oct. 4, 1921.

3 SHEETSSHEET 2.

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H. M. AND T, M. CHANCE.

METHOD AND APPARATUS FOR CLASSIFYING MATERIALS.

APPLICATION HLED JULY 8,1918.

1,392,401, Patented Oct. 4, 1921.

3 SHEETS-SHEET 3- FIG. III.

W/f 655 5 i A A40, mafia, gi

enZbrJ UNITED STATES PATENT OFFICE. HENRY M. (##ANCE, AND T HOHAYS M. CHAId'CE; I

METfiOD.AND APPARATUS FOR CLASSIFYING KATEBIALS.

,3 ,4 v Specification of Letters Patent. P t t t, 4, 2 Application filed July 8, 1918. Serial No. 248,911.

To all whom it may concern: gravities, sizes and shapes. All materials Be it known that we, HENRY M. CHANCE in a vacuulnfall with equal velocity, irreand THOMAS M. CHANCE, citizens of the spective of weight, shape or size, but in fall:

United States, residing at Philadelphia, in ing through air, wateror any fluid medium,

5 the city and county of Philadelphia, State the lighter, the smaller and the flat pieces 60 of Pennsylvania; and at Baltimore, State lying horizontally are retarded more than of Maryland, respectivel have invented a the heavier, the larger and the flat pieces certain new and useful ethod and Apparalying vertically. tus for Classifying Materials, whereof the This retardation is reater. in liquids of following is a specification. high specific gravity t an in those of low 65 Our invention consists of an improved specific ravity, and is, reater in viscous method and apparatus for classifying mal1quids t an in liquids o high mobility or terials having difi'erent falling velocities in fluidity. The differences in retardation liquid, and may be carried out by the aid caused by the specific gravity of the liquid,

of appliances similar to those in common use are due to the differences in the loss of 70 for the classification of ores, etc., such as are weight of'materials immersed in the liquid,

known as classifiers, jigs, surface current because in materials of relatively low speclassifiers, trough washers, upward current cific gravity the losses in weight due to 1m-v classifiers, etc., and which are used in sepamersion may be a large percenta e of their rating, by means of differences in falling veactual weights, while in those 0 relatively 75 locities in liquid, the materials to be treathigh specific gravity the losses in weights ed into classes having equal, or approxidue to immersion may be asmall' ercentage mately equal, falling velocities. If such apof their actual weights.- The di erences 1n pliances be used in separating materials of retardation caused by the viscosity of a different specific gravities, but of the same liquid in which the falling materials are im- 80' size, shape and character of fracture, the mersed are in addition to those caused by materials composing each class so separated the losses in weight d he specific gravwill consists of particles having 'approxiity of the liquid, andare due to the resistmately the same specific gravity, but when ance to movement produced by the viscosity the individual particles of such materials of the liquid.

differ materially in size or in shape, the Retardation due to viscosity does not slower falling-classes so separated will conafiect the falling velocities of materials of tain relatively large pieces of light mate. different specific gravities or of different rial, smaller pieces of heavier material and sizes, or of difi'erent shapes in the same way flat or oblong pieces of both lighter and that weight, sizeand shape affect falling heavier material, while the more rapidly i i in l quids f high mobility or falling classes will contain relatively large fluidity because the retardation of each par pieces of heavy material with more or less ticle due to viscosity depends upon the abilof the fiat or oblong pieces of the lighter ity of eadh particle, by reason of its weight,

4 materials.

. not only to tear itself free from the viscous The object of our invention is to improve envelop of liquid that is clinging to it, but separations. of this description by the use to force apart the viscous liquid below it, of fluid masses of higher specific gravity. making a path through which it can sink. than the liquid constituent of such fluid The relatively small particles, those with 45 mass, whereby the difierences in the relatiy e small -masses and correspondingly small weights of materials immersed in said fluid gravitational forces due to their small im-. mass are greater than the differences in the mersed weights, have relatively large-surrelative weights of said materials when imfaces (as compared with the masses and surmersed in water or other lighter liquid. faces of larger particles) to which the vis- 50 Classification, or the separation of matecous liquid adheres, and are retarded, rela- 105. rials into classes of equal falling velocities, tively, more than the larger .,particles. On actually, depends not upon differences in the the other hand with particles of the same falling velocities of materials but upon difsize, but of different specific gravities, the ferences in the retardation in the falling additional retardation caused .by the v is 55 'elocities of materials of different specific cosity of .theliquid, because of the'difierence in the immersed weights'of the particles, will be greater for those of low spec fic gravity than for those of greater specific gravity.

While this property of viscous liquids to retard (or to prevent) the sinking of small particles of relatively heavy material and larger particles of relatively l1ghter materials, may perhaps have useful applicat on in the arts, it becomes detrimental 1n the carrying out of our improved method for classitying materials'by means of a fluid mass consisting of an agitated mixture of liquid and comminuted insoluble solid matter, heavier than the liquid, this fluid mass being the medium in which and by which classification'is effected.

The use of liquids and solutions of relatively high specific gravity for the classification of materials such as ores and the like in various forms of classifiers and jigs is known, and the use of mixtures of liquids and finely divided insoluble solid matter such as clay, mud, silicates of alumina, fire clay and the like, which when mixed with liquid tend to remain suspended in it, is also known. Attempts have been made to effect improvement in classification by utilizing the greater losses in the weights of materials immersed in liquids, solutions or'mixtures of relatively high specific gravity, as compared with the losses in weightsof such materials immersed in water or other liquid of less specific gravity.

Our invention relates to the use of fluid masses of relatively high specific gravity consisting of agitated mixtures of liquid and comminuted insoluble solid matter heavier than the liquid, in the classification of materials by means of the differences in the relative falling velocities, in such fluid masses, of materials of different specific gravities, sizes, shapes and cleavage. Our improvement consists in the production and maintenance of such fluid masses by using as the principal solid constituent of such fluid masses comminuted insoluble matter heavier than the liquid, the individual particles of said matter being of such material, size, shape and nature as tosink by gravity in the liquid used and that require continual agitation to maintain and to preserve the homogeneity of the fluid mass by keeping the particles of solid matter distributed through the liquid to form a fluid mass of the desired specific gravity and of low viscosity, and in the classification of materials differing in their specific gravities, sizes, shapes, cleavage or other physical properties, by'immersion in said fluid mass.

In the classification of such materials by mixtures of relatively high specific gravity consisting of liquid and clayey materials, or the like, such as tend to remain in suspension in the liquid, the viscosity of such mixlow viscosity,

ratus is always designed to reduce, so far as I is possible, the production of eddy currents and to.control or to minimize their effect. The handling of a liquid or of a mixture of relatively high viscosity in any known type of apparatus used for the classification of materials cannot be effected without the production of eddy currents, and the suppression or control of eddy currents in a viscous liquid or viscous mixture presents greater diffi'culties than those to be overcome when the liquid or mixture has relatively high mobility or fluidity. The effect of eddy currents in preventing proper'classification of the materials, by causing a remixing of materials sought to be separated, is also much greater with viscous liquids or viscous mixtures or suspensions than with those having high fluidity.

In thus comparing the conditions attendant upon the use of mixtures of relatively high viscosity with fluid masses of relatively we do not intend to convey the impression that viscous mixtures cannot be used in classifying materials of different specific gravities, sizes and shapes, because the loss in weight of such materials by immersion may even in quite viscous mixtures or suspensions in some cases ermit a useful classification of the materias to be made; but in most cases such classification can be made more easily, more quickly and with greater certalnty, and each class of material separated will contain less material that properly belongs with other classes, when a fluid mass of high mobility and fluidity is used than when a mixture of a viscid type is used.

We are aware that the difference in the falling velocities of materials suspensions or mixtures of mud, clayey, or other similar materials which tendto remain suspended in water and which do not quickly settle by gravity, has been used in separating materials of different specific gravities, and we do not herein claim the use of mixtures of liquid with very finely divided solids of such types. Such mixtures do not produce fluid masses of the type used in carrying out our invention, but produce a .mud having relatively high viscosity in which the materials do not quickly or readily sink, whereas fluid masses ofthe type used in carrying out our invention have a immersed in they must lie ver difference in viscosit fluidity (or mobility) approximating that of the water or other liquid used in producing them. This specific difference in viscosity may perhaps be due in part to' the fact that when solid matter is in an extremely finely subdivided condition, the individual particles have such small mass that close to each other in such mixture, per aps being separated by a mere film of water or other liquid used (or may have a film of liquid strongly adheringto each particle, constituting a liquid envelop that attracts. and adheres to. other like envelops), so that the attraction of particle for particle tends to tie the mass together and thus produce a mixture of rel-, atively high viscosity and low mobility, whereas if of particles that are of such size and weight and character as to fall freely in water, or other liquid, and that require continuous agitation to keep them suspended in said liquid, then a fluid mass of relatively high gravity is produced having a viscosity w ich may be very little, if appreciably, greater than that of the liquid used. Whether this be the true explanation of the or not, or whether the cause may not be ueto some other prop erty of such materials, the fact remains that fluid masses of the described type are highl fluid, whereas mixtures of relatively hig specific gravity consisting of liquid and ma-' terials that do not readily sink in the liquid are more or less viscid. e find, for example, that with mixtures of water and ordinary quartz sand, such as may be found alon the New Jersey coast, fluid masses of relatively high specific gravit can be produced, say 1.50 to 1.70, and 0 such perfect fluidity, that the hand when passed through water superimposed upon said fluid mass can enter the fluid mass below it without detectin the difference in the fluidity-of the said uid mass and of the water superimposed upon it, and that the hand or any ob.- ject immersed in such fluid mass .can be withdrawn without having any considerable quantity of such fluid mass adhering to it, whereas this is not true of fluid masses of relatively. high specific gravityponsisting of clay or other similar material mixed with water, unless the immersed object be greased or very highly polished. In utilizing the differences in falling velocities of materials in such fluid masses forthe. separation 0 materials of different specific gravities, we are able to eflect separations which cannot be effected, or that cannot be ed,'with mixtures consisting largely or pr ncipally of clay-like or other materials which tend to form mixtures of relatively high viscosity.

- The differences the relative weights of.

materials when immersed in fluid masses of I weights of these In a fluid mass of a mixture be produced consisting P relatively high specific gravity are very much greater than the differences. in the materials in water or in air. Foran example, if the specific gravities of coal, bony coal and slate be respectively 1.30, 1.45 and 2.00, their weights in air, in

water and in a fluid mass of 1.25 specific gravity, are in the ratios;

Relative weights.

- -Coal. Bony coal. Slate. In air, as 65 t0 72%t0 100 In water, as 30 to 45 to 100 1.25 sp. gr., as 6% to 25% to 100 and as the falling velocities of materials, for

particles of equal size and similar shape, de-

nd upon their relative immersed weights, it is evident that the falling velocities of the lighter as compared with the heavier materials immersed in said fluid mass relatively will be very much less than the falling velocities of these materials when 1mmersed in water or other liquid of less spe- I cific gravity than said fluid mass, hence in using a high gravity fluid mass to effect such separations, it is important that the fluid mass should be highly mobile or fluid and not sticky or viscid, because high viscosity will further and greatly retard, and

in many cases will prevent, the separation from being made, and in all cases will prevent the separation from being as completely efiected as when a non-viscous fluid mass is used.

In a atent issued to Thomas M. Chance dated ay 1, 1917, No. 1,224,138 formethod and apparatus for washin coal andconcentrating ores, the use of uid masses of a type somewhat similar to those herein described is described and claimed for separatmaterials of different specific gravities the flotation of the lighter constituents ing and the sinking of the heavier constituents,

the fluid mass used having a specific gravity high enough to effect flotation of the lighter constituents of the materials to be separated but low enough to permit the heavier constituents to sink. In that patent, separation or classification by velocities is not described or claimed, the separation by flotation being eflected by differences in specific gravity irrespective of the size or shape of the materials to be separated. In an application filed August 27,

f 1917, Serial No. 188,431, Thomas M. Chance has described the use of a compound fluid mass comprising two or more zones of different specific gravities and has claimed the same for making separation of three or more materials of different specific gravities, using fluid masses of a type somewhat similar to those herein described, but the separation as described and claimed therein is by flotation of the lighter and sinking of the heavier differences in falling equal falling velocities) materials irrespective of the size and shape of the materials and of the differences in falling velocities of the materials in such fluid masses.

In the operation of the present invention if materials of leSs specific gravity than that of the fluid mass be present in the materials to be classified, they will of course be removed by flotation as described in said Patent No. 1,224,138 above cited, and this may at times occur accidentally or incidentally in some of the types of apparatus used in the practice of our method, and by differences in the specific gravity of the fluid mass occurring in different parts of the apparatus, 'ut we do not herein claim separation of any constituents ,of the materials to be classified by flotation due to the specific gravity of the fluid mass being sufficient to float such constituents, nor do we herein claim the separation by sinking of heavier constituents of such materials in such fluid mass because such constituents are of greater specific gravity than that of the fluid mass, and we have therefore limited our claims herein to method and apparatus whereby classification (or separation into classes of approximately is effected by the differential action of fluid masses of relatively high specific gravity in retarding the falling velocities of the materials to be separated, whereby it becomes possible to separate the materials into two, three or more classes in each of which the constituents thereof have approximately equal falling velocities in the fluid mass used, and in which such classification is effected by, and results from, differences in the falling velocities in such fluid mass of the materials to be classified.

For reasons already given we do not claim herein separation or classification by means of mixtures in which the comminuted solid constituent particles whereof tend, byreason of their character, size, shape, composition or-other physical property, to remain suspended in the liquid constituent thereof, or which do not readily sink or settle by gravity in said liquid constituent, and we therefore have limited our claims herein to a method and apparatus whereby classification is effected by fluid masses of the described type which require continuous agitation to keep the solid particles thereof in suspension, and to the use, in effecting such classification, of solid matter of such nature as will, when agitated with liquid, produce fluid masses of high mobility and relatively low viscosity.

The drawings Figures I, II and III illustrate the application of the method to some types of classifying and concentrating appliances, but it will be understood'that the application of the method is not confined to these particular types of appliances.

'vided with an inlet for water under pipes, 12, 12, suitable for They are vertical cross-sections and elevations of three different types of apparatus embodying our invention.

Fig. I is a vertical cross-section and elevation showing the working parts of a coal jig of the movable pan type actuated b an eccentric, and in which the two pro uots made, coal and jig rock(slate etc.), are discharged into scraper conveyers for removal from the jig tank, like many in common use in the anthracite Pennsylvania.

The apparatus as shown consists of a tank or rece tacle 1, adapted to contain a fluid mass of the described type and a fluid mass 2 contained therein and filling said tank 1 up to or approximating the position of the overflow outlet 3. The fluid mass numbered 2 is indicated by the broken horizontal lines used conventionally to represent liquid (water) and stippled to represent the solid constituent of said fluid mass. The bottom of the tank 1, consists of perforate plates 4, 5, 6, 7, below which are pressure chambers 8, 9, 10, 11 under pressure, and each of which is proprescoal fields of.

sure, shown as connectionto any suitable source of supply of liquid under pressure, and a clean-out hole 13 with valve or cock shown as a plug, 14, for closing same. The movable pan 15 is actuated by the eccentric 16 through the eccentric rod 17, to which it is attached and guided inits movement by the pin 18. This pan 15 is provided with a perforate bottom with perforations 19 large enough to permit of the free flow through them, and with an adjustable feedgate 20 controlling the coal feed chute 28 and an ad'ustable slate delivery gate 21.

The coaf discharge chute 22 delivers the coal to one side of the center line ofthe pan 15, so that the coal will fall into and be removed by the coal scraper elevator 23, and the slate discharges through the gate 21 on the opposite side of the center line of the pan 15 so that with the aid of the warped baffle plate 24 it will fall into and be removed by the slate scraper elevator 25. In apparatus of thismovableapan jig adapted to hold water of the fluid mass 2 type the coal (ore or other material) and material to be separated therefrom is fed into the movable pan 15 from the feed chute 28, and fills the pan to the level of the top of thecoal discharge chute 22. The

mass of materials filling this pan is raised at each upward stroke thereof. produced by revolutions of the eccentric 16, .and falls .under action of gravity during the downdium in which the jigging is carried out, valve or cook, shown as a plug, 14, for closbut with this important difference that ing same.

owing to the fact the fluid mass has higher The fixed pan or compartment 26 is prospecific gravity than that of water the difvided with a perforate bottom with perfoferencesin the falling velocities of the marations 19' large enough to permit the fluid terials underseparatmn is greater than if mass 2 to flow through them andwith an water alone is used as a fluid medium, so adjustable slate delivery gate 21. The coal that the faster fallingkparticles of said marides over the coal discharge lip 27 and is terials 'fall more quic ly as compared with removed by the coal scraper elevator 23 and the slower falling particles and the sepathe slate discharges through the gate 21 to ration is thus more rapidly and full efthe slate scraper elevator 25. The feed from 7 fected than when the separation is .pro need the coal feed chute 28 is controlled, disbTy differences in falling velocities in water. tributed and directed by the adjustable feed he more rapidly falling material, com risgate 20. The fluid mass 2 is caused to puling the reject, if coal is being washe or sate or to oscillate through the perforations concentrates, if ore is being concentrated, 19 by the reciprocating motion of the plunis delivered from the lower portion of pan ger or piston 29 actuated through the con- 15, under gate 21 to elevator 25, warp baflie necting rod 17 by the eccentric 16'. The 24 assisting this delivery while the slower tank is provided with perforate baffle plates falling material, comprising the coal, if coal. 30 to control the directional flow of the is being washed, or refuse if ore is being fluid mass, the perforations in said baffle concentrated, dischar es through chute 22 plates being. large enou h to permit flow of into elevator 23, sai elevators 23 and 25 the fluid mass 2 throug them.

servinglto remove'the separated materials In apparatus f his fixed p n g type from t e fluid mass. In the drawing Fig. the operation is similar to that of t e mov- I a shallow body of water is shown superable pan type above described, the mateimposed above the fluid mass. This body of rials to be separated in this case being raised water is practically the same in quantity as by each upward ulsation of the fluid mass that which is supplied through the perfothrough theper orate bottom of the fixed rate bottom and sides to provide agitation pan and falling in said fluid mass during the of the fluid mass, the water so admitted downward pulsation of the fluid mass, the rising through the fluid mass and flowing separation being by difference, in falling veout of the apparatus through the overflow locities between the particles of materials to 3. It will of course be understood that be separated, these differences being greater 7 while the drawings all show a body of in the fluid mass than in water, the separatliquid above the fluid mass, such supering action occurring in part during both natant liquid is not an essential part of our the upward and downward pulsations of invention and has not been claimed herein. the fluid mass, the difference in falling ve- Fig. II is a vertical cross-section and locities causing the slow falling particles to elevation showing the working parts of a be lifted more rapidly as compared with coal jig of the fixedpan, water pulsation the faster falling articles during the uptype, in which the two products made, coal ward pulsations, t an if water is used as and jig-rock (slate 'etc.), are discharged the fluidmedium in which to jig the mafrom the pan into or within the reach of terials, thus making more rapid and efliscraper conveyers for removal from the apcient separation of the materials. The' .paratus, like many in common. use in the more rapidl falling material comprising anthracite coalfields of Pennsylvania. The the reject, i coal is being washed, or conapparatus as shown consists of a tank or centrate, if ore is being concentrated, falls receptacle 1, adapted to contain a fluid mass" to the perforate bottom of the fixed pan'26 of the described type, and 'a fluid mass 2 and is translated laterally across said botcontained thereinfilling said tank 1 up to, tom by the pulsations of the fluid mass,

or a proximating to, the position of the this movement being induced by reason of over ow outlet 3. The fluid mass numbered the inclination of said perforate bottom.

2 is indicated by the broken horizontal lines Said faster falling materials pass under used conventionally to 'represent' liquid gate 21 and into elevator 25 wh1le the slower (water) and stippled to represent the solid falling materlal rides across said pan 26- constituent of said fluid mass. The bottom and passes over dlscharge 11p 27 into eleof the tank 1 consists of a perforate plate vator 23, said elevators 23 Mid 25 serving 4 below which is a pressure chamber 8, to remove the separated materials from the adapted to hold water under pressure, and fluid mass. .Inthe drawing Fig. II the is provided with an inlet orinlets for water, fluid mass has shown su enmposed upon it shown as a pipe 12 suitable for connection a thin body of water t e height of wh ch to any suitable source of-supply of liquid is limited by the overflow 3. In the casing under pressure and a clean-out hole 13 with to elevator 25, a h gher body of water 1s shown above the fluid mass'in the bottom of the'elevator casing. This condition arises from the fact that the elevator casing not being supplied with agitating means, the sand of the fluid mass drops to the lower part of the casing, leaving clear water, or water with very little sand, in the upper portion and the hydrostatic pressure of the greater height of fluid mass in the jig tank I 1, maintains the surface of water in the elevator boot 25 at a greater height than. the overflow 3. I

' Fig. III is a vertical cross-section and elevation showing the application of the method in using appliances similar to those used in surface current classifiers and trough washers, in which 40 is a trough or tank the bottom of which consists of a number of hoppers or pockets 41, 41 41", 41, with per-- forate sides or inclined bottoms 42 below which are pressure chambers 43 supplied with liquid under pressure from the pipes 44 through a conduit 45 in communication through a control valve 46, with a pump 47 driven by power from any suitable source. The perforate bottoms 42 are for the supply of hydraulic liquid (water) for the agitation of the fluid mass contained in said pockets (41, 41, 41 and 41). This liquid, together with that introduced by small pipes 60 at or below the base of said pockets, permit the maintenance of uniform fluidic properties throughout said pockets, the liquid introduced by small pipes 60 supplying agitation over that area of the pockets not covered by perforate bottoms 42 and thus preventing,

the formation of solid banks in the lower portions of said pockets that would hinder the fall of the separated materials prior to withdrawal from the apparatus. A further function of the liquid introduced to maintain agitation in the pockets 41, 41 41 and 41 is to assist the agitation of the body of fluid mass flowing through trough 40. The

tank or trough 40 is provided with outlet 48, for fluid mass passing, over the adjustable overflow gate 49, connected with a pump 50 and conduit 51 and with a discharge 52 at the upper end of the trough or tank 40, the operation of which continuously pumps fluid mass into the upper end of said trough or tank 40 and continuously removes fluid mass from the lower end of said trough, thus "establishing a flow of fluid mass through the the perforations in the sides or-bottom of i said hopper larger or more numerous than those in the sides or bottom of the precedingby liquid (water) flowing from the pipes 44 through the small pipes 60 which discharge into or below the base of the pockets 41. The material thus trapped out is discharged on dewatering screens 61, the water and fluid mass passing through these screens into the .trough 62, which is provided with hoppers 63 to catch the sand, which flows through the conduits 64 to the inlet of a pump 65, through which it is returned by the conduit 66 to the trough or tank 40, the water thus trapped into the tank-62, together with overflow water from tank 41, flowing through the pipe 67 to tank 62 flows into the suction of the pump 47. The tank 62 is provided with liquid (water) supply through 68 by means of constant level valve and float 69 and 70. An overflow wier 71 is provided to keep the top of liquid (water line) in tank 40 at an desired level.

n apparatus of this trough type, the materials to be separated are fed into the fluid mass flowing through the trough 40 and are thus translated longitudinally while they are falling in the fluid mass, those particles of higher falling velocity reaching the bottom of the trough or the pockets 41, '41, in the bottom after traveling a less distance than the particles of slower falling velocity, the operation being similar to that which takes place in trough and surface current .classifiers in which classification is effected through differences in falling velocities in water of the material to be classified, with this important distinction, that in our invention the differences in falling velocities of the materials to be separated is greater than their differencesin falling velocities in water, thus effecting a more rapid and eflicient separation. In the drawing Fig. III the fluid mass occupying the tank 40 and pockets 41, 41 41 and 41, is diagrammatically indicated by nearly horizontal broken lines representing liquid (water) and stippling to represent the solid component (sand) ofsaid fluid mass, and liquid (water) superimposed thereon is diagrammatically represented as occupying the space between the lines A--A and BB by nearly horizontal broken lines.

It will be observed that in the operation of the method in all \of these types of appliances, and this applies to any type of applanet in which the method may be carried out, that the material to be classlfied, or separated into 'diflerent classes, must be completely immersed in the fluid mass so fication of vent the fine and than those 'having the ving for that the different materials may separate in different zones or in different parts of the apparatus by reason of the time element introduced by the differences in falling-velocities.

It will also be noted that thismethod pro- .vides a means for the separation by classimiddlings, less falling velocity falling particles an tion of washing,

to the best coal.

It will be understood that in emplo ing jigs of the plunger type apparatus in e ecting classification, that the suction stroke should be suppressed-if it be desired to preheavy particles from being thrown down into the hutch, and that this can be done by the use of hydraulic water, valved plungers or other means in use in the operation of jigs for suppressing the effect ofthe suction stroke.

It will be understood that the perforations in the plates shown on the drawing are not made to scale, but that the holes may be ofsuch diameter and such spacing from center to center as will pass suflicient liquid under the head .used to effect the desired agitation. It will be understood further that perforated plates as shown by the apparatus are intended diagrammatically to indicate the location of such plates, and that plates of other types of'construction than thoseshown may be used, such as those with wearing plates or strips to protect the plates from attrition caused by. scraper flights, conveyers and material dragged over-them, such as have been used for the protection of perforated plates from wear,and that for the purpose of such protect-ion a heavy perforated plate may be superimposed upon a smaller or lighter plate.

Before proceedmg to carry out our method of classificationby means of fluid masses of the-described type, by applying itto the-classification of any given material,

the material should be prepared b removing, by screening,

or other means, ose particles that are too small for classification by the fluid mass that is to be used.

' pended 1 as a constituent which may consist of low grade; coal and bony coal which has value as fuelbut is not equal 'If to a fluid mass of the described type there be added (through the introduction of materials to be classified) particles approximating in size to that of the particles of the solid constituent of the fluid mass, such added particles if appreciably heavier than those composing the fluid mass, will (unlessthe be' violently agitated) tend to sink to the vlower part of the fluid mass and there form a fluid mass of correspondingly higher specific gravity, or, will remain suspart of the fluid mass, correspondingly increasing-its specific gravit or, if lighter than the solid constituents 0 said fluid mm will tend to remain as a constituent part of said fluid mass, correspondingly' decreasing its specific gravity, or will rise above the fluidmass and there remain, superimposed as a fluid mass of less specific gravity upon the fluid mass used.

The disposition in .the fluid mass of particles approximating in size to those of the fluid mass will spend largely uponthe character of the agitation by which the fluid mass is maintained at the desired specific gravity, and will also depend lar ely upon the specific gravity of-such particles and to some extent upon bly upon other physical propertles.

In studying the properties of fluid masses of the described type, it should be remembered that while such fluid masses exhibit most of the physical properties of true liquids of high specific ravity, in that they produce the same by rostatic pressures as liquids of the same specific gravities, cause bodiesimmersed in them to lose the same weight as if immersed in a liquid of equal specific gravity, seek their own level like true liquids, flow over a weir like a true liquid, etc., yet they do not act precisely like liquids of high specific gravity uponbodies immersed in them which approximate in their shape and 1- size to (or are smaller than) the particles of their solid constituents, immersed bodies of such size being acted upon by the agitation supplied to keep thesolid constituents of the fluid mass in suspension and therefore tend to become a constituent of the fluid mass. The introduction of particles approximating in size to those of the fluid mass merely constitutes an addition to the fluid mas unless the particles added are much heavier or' much lighter than those of which the fluid mass is composed. The materials to be classified by the use of this method-should therefore be appreciably larger, or much heavier, than the particles composing the fluid mass, in other words, they must be capable of sinking in such fluid mass and vof developing marked diflerences in their falling velocities in said fluid mam.

The drawings show the admission of liquid constituent of the fluid mass to efl'ect or to mamtam or to assist in maintaining agitation in the form of jets from a source of liquid supply underpre'ssure, these ets being vertical or at any desired angle, the jets issuing from the orifices of pipes, tubes or nozzles of any desired form, shape, or length, the small perforations in the perforated plates being intended to represent diagrammatically such tubes, pipes or onfices, and are in fact tubes of short length connected to a source of supply of li uid under pressure. 'It will be further un erstood that the quantity of liquid so admitted and used may vary from none up to any desired quantity, depending upon the degree of agitation produced by other means provided to maintain the fluid mass of the required consistency.

It will be understood that in carrying out our invention we do not limit ourselves to the use of the particular appliances shown by the drawings nor to the details of these appliances, nor to the particular means shown to effect agitation, to feed the materials into the apparatus or for removing the materials after separation is effected, as these must be adapted to the character of materials to be separated; thus, the removal by trapping out the materials, as shown by Fig. III, is best adapted to be used when the materials are relatively fine, removal by elevators, indicated diagrammatically by the scraper conveyers shown by Figs. I and II being better adapted to the purpose when the materials to be separated are relatively coarse.

.In using the type of fluid mass herein described as a medium to effect classification,

the fluid mass may be agitated by any known means for effecting agitation of fluid masses, either by circulation of the fluid mass, by mechanical appliances or by fluid lntroduced under pressure, that is, with sufficient velocity to effect agitation. The drawings illustrate means for effecting agitation by all of these methods, the centrifugal pump, the plunger, the movable pan and the pressure chambers with jets issuing through the perforate plates being intended diagrammatically'to show agitation by circulation, by mechanical and by hydraulic means.

When liquid (water) is the sole means used for agitating the fluid mass, the velocity of the upward current of liquid in the a paratus as a whole must be less than the alling velocity in the liquid of the smallest solid particles of the fluid mass, unless it be deslred to carry the fluid mass out .of. the apparatus.

Our invention is also useful in combination with the use of the method-of said Patent No. 1,224,138 and constitutes an improvement by which a .middlings product can be separated, that is, a product heavier controlling the disposition of such mid dlings product by causing'it to remain with either the lighter or the heavier product as may be desired, or for splitting it into two products of different specific gravities and different falling velocities. In the operation of the method described in the above mentioned Patent No. 1, 224,138, as applied to coal washing, it the fluid mass used be of high enough specific gravity to float both pure coal and coal of rather high ash, then some bony (very high-ash) coal approximating in specific gravity to that of the fluid mass, may not readily sink, but by sli ht eddy currents in the fluid mass, or by being held up by the buoyancy of lighter pieces of coal, may remain with the coal and be discharged with it; if the specific gravity of the fluid mass be reduced to permit this bony coal to sink readily, then some of the rather high-ash coal is likely to be carried down by eddy currents or by becoming enmeshed with the slate, fireclay and bony coal, so that the reject may consist of a mixture of slate, fireclay, bony coal and rather high-ash coal. Similarly,in the concentration of ores by the method of said Patent No. 1,224,138, in which the gangue,

or waste, is to be floated by the fluid mass and the ore permitted to sink through the fluid mass, particles of low-grade ore (miding coal and concentrating ores, Serial No.

188,431, and we donot herein claim the use of compound fluid masses, although the operation of the method described in this application may at times incidentally or accidentally create zones of different specific gravities in the. fluid mass employed in the operation of our new method as herein described, but such zones are not used toeffect separation by flotation. When the fluid mass used is of less specific gravity than that of the materials desired to be thus separated, separation into classes cannot be effected by a purely gravimetric or flotation'method, as described in said Patent No. 1,224,138, but can be effected by utilizing the differpieces of gangue con size respectively,

ences in the falling velocities of said materials in said fluidi mass, as described in the operation of our; present invention.

The effect of viscosity in a fluid mass is to make a greater relative reduction in the falling velocity of materials of relatively low specific gravity and in the falling velocity of particles of material of higher specific gravity but of relatively small size, than in the falling velocity of materials of relatively higher specific gravity and in the .falling velocity of particles of relatively larger falling velocity of particles of relatively small size and inmaterialsof relatively sinking and causes. them to be buoyed up readily by relatively slight eddy currents in while it increases the time required for the separation of all classes of materials, renders the separation sluggish, reduces the possibility of making a clean separation and greatly increases: the difliculty of separating solid matter of the fluid mass adhering to the separated products from such products.

In practisin the method of separation by flotation, U. Patent No. 1,224,138 above referred to, moderate viscosity of the fluid mass may not retard or prevent satisfactory separation of material lighter than the fluid mass from material heavier than the fluid mass, (except possibly as to the separation of very small particles. of the heavier material), but when for the purpose of separation certain-materials must be permitted to sink so as to fall farther than other materials from which they are to be separated and certain other materials must be per mitted to sink and fall farther than either, withperhaps still others that must fall still farther in a given time, such separation can be eifec'ted more quickly and efliciently by usin a fluid mass of low viscosity than one of. high viscosity.

Our invention is based upon our discovery of the remarkable fluidity or mobility of fluid masses that may be produced by the means herein described, upon our discovery of the very low viscosity of such fluid masses, upon the peculiar advantages that may be attained by employing such fluid masses as a medium (substitute for water or other liquid) in which to effect classification through. difierences in the falling velocities in such fluid masses of the materials to be separated by classification and upon the advantages such fluid masses possess over fluid masses of a more or less viscid type. These discoveries were made by us in experimenting with difierent forms of apparatus for carrying out the two inventions of Thomas M. Chance relating to flotation by fluid and this reduction in the low specific gravity tends to prevent them from masses above referred to, andii one other invention of his for which he filed a plication for.- .patent on August 27 ,'1917 erial N 0. 188,430. g

The term fluid mass as used in. this specification and the claims; hereof, is intended to designate an; agitated, mixture of relatively low' viscosit consisting of liquid and comminuted. soli the liquid and insoluble therein, such-solid matter consisting principally of appreciably coarse granular materia of such kind, size,

shape and nature as to sink'readily by gravity in said liquid and that requires continuous agitation to keep it suspended in the liqmatter: heavier than uid" and to maintain the fluidic properties,

relatively high specific gravity and relatively low viscosity of such fluid mass; the term middlings is intended to mean and to include constituents of the materials. to be separated that are heavier than the lighter constituents and lighter than the heavier constituents of saidmaterials, in ores con-- sisti-ngprincipally of low-grade ore and in coal of high-ash or bony (very high-ash) coal; the term ore or ores is intended to include materials containing non-metallic: elements or substances (e. g. graphite, etc.) and also to include metallic products, (6. g. metallic filings mixed with other material) materials and substances such as ordinarily would not be called ores but which have properties orqualities that permit of their separation by the method herein described; the term water is intended to mean any liquid suitable for making a fluid mass of the described type, and .the term sand is intended to mean any appreciably coarse granular insoluble material heavier than the liquidused and suitable for making a fluid mass of the described type. It will of course be understood that the specific gravity of the fluid mass used in carrying out our invention must be less than the specific gravity of the materials which are to 'be separated, separation being effected by differences in falling velocities of such materials and it is evident that unless the specific gravity of the fluid mass is less than the specific gravity of these materials, they would not fall through it but would float upon it. The fluid mass used in carrying out our invention must, moreover, be of greater specific gravity than the liquid component of said mass in order that it function to check the falls of thematerials to be separated at ratios difl'fering from the falling ratios of said materials in that liquid alone.

Having thus described our invention, we claim,

1. The method ofseparating materials of unlike physical characteristics which conmixture of liquid and comminuted granular fluid mass and said solids being of such nature as to remain suspended in a hydraulic current that will not support the materials to be separated by diflerences in falling velocity; in causing said materials to fall in said fluid mass, whereby the materials of relatively high falling velocity position themselves below those of relatively low falling velocity, the differences in falling velocities of said materials being greater in said fluid mass than in said liquid alone; and in separately removing said materials so positioned from said fluid mass.

2. The method of separating materials of unlike physical characteristics which consists in submerging said materials in a continuously agitated fluid mass composed of a mixture of liquid and comminuted granular solids, said said liquid of less specific gravity than said fluid mass and said solids being of such nature as to remain suspended in a hydraulic current that will not support the materials to be separated by differencesin falling velocities; in causing said materials to fall in said fluid mass, whereby the materials of relatively high falling velocity position themselves below those of relatively low falling velocity, the differences in falling velocities of said materials being greater in said fluid mass than in said liquid alone; in separately removing said materials so positioned from said fluid mass; in separating from said materials so removed portions of c said fluid mass admixed therewith; and in returning to said fluid mass portions of said mass thus separated from said removed materials. p

3. The method of separating materials of unlike physical characteristics which consists in submerging said materials in a continuously agitated fluid mass composed of a mixture of liquid and comminuted granular solids, said materials being of greater and said liquid of less specific gravity than said I fluid mass and said solids being of such nature as to remain suspended in a hydraulic.

current that will not support the materials to be separated by differences in falling velocities; in causing said materials to fall in an upwardly rising current of said fluid mass whereby the materials of high falling velocity position themselves below those of low falling velocity, the differences in falling velocities of said materials in said fluid mass beinggreater than in said liquid alone; and in separately removing said materials so' p0- sitioned from said fluid mass.

4. The method of separating materials of unlike physical characteristics which consists in submerging said materials in a continuously agitated fluid mass composed of a mixture of liquid and comminuted granular materials being of greater and solids, said materials being of greater and said liquid of less specific gravity than said fluid mass and said solids being of such nature as to remain suspended in a hydraulic current that will not support the materials to be separated by differences in falling velocities; in causing said materials to fall in a moving current of said fluid mass, said fall and said motion coacting toposition the materials of high falling velocity in a zone relatively remote from that occupied by the material of relatively low falling velocity, the difference in falling velocities of said materials in said fluid mass being greater than in said liquid alone and in separately removing said materials so positioned from said fluid mass.

5. The method of separating materials of unlike physical characteristics which consists in submerging said materials in a continuously agitated fluid mass composed of a mixture of liquid and comminuted granular solids, said materials being of greater and said liquid of less specific gravity than said fluid mass and said solids being of such nature as to remain suspende iina hydraulic current that will not support the materials to be separated by differences in falling velocities; in causing said materials to fall in a moving current of said fluid mass, said fall and said motion coacting to position the material of high falling velocity in a zone relatively remote from that occupied by the material of relatively low falling velocity, the differences in falling velocities of said materials being greater in said fluid mass than in said liquid alone; in separately removing said materials from said fluidmass and in returning to said fluid mass portions of said mass admixed with said materials.

6. Apparatus for the separation of materials of unlike physical characteristics comprising in combination a receptacle adapted to contain a fluid mass; a continuously agitated fluid mass contained therein composed ot-a mixture of liquid and comminuted solids, said materials being of greater and said liquid of less specific gravity than said fluid mass and said solids being of such nature as to remain suspended in a hydraulic current that will not support the materials to be separated by differences in falling velocities; means for submerging said materials in said fluid mass; means for separately removing said materials from said mass after they are positioned in different zones by reason of their different rates of fall in said mass; and means for agitating said fluid mass.

7. Apparatus for the separation'of-materials of unlikephysical characterstics comprising in combination a receptacle adapted to contain a fluid mass; a continuously agitated fluid mass contained therein composed of a mixture of liquid and comminuted solids, said materials being of greater and said liquid of less specific gravity than said fluid mass and said solids being of such nature as to remain suspended in a hydraulic current that will not support the materials to be separated by differences in falling velocities; means for submerging said materials in said fluid mass; means for separately removing said materials from said-mass after they are positioned in different zones by reason of their different rates of fall in said mass means for agitating said fluid mass and means for reclaiming and returning to said fluid mass portions thereof admixed with the separated materials removed therefrom.

8. Apparatus for the separation of materials of unlike physical characteristics comprising in combination a receptacle adapted to contain a fluid mass; a continuously agitated fluid mass contained therein composed of a mixture of liquid and comminuted solids, said materials being of greater and said'liquid of less specific gravity than said fluid mass and said solids being of: suchv nature as to remain suspended in a hydraulic current that will not support the materials to be separated by differences in falling velocities; means for submerging said materials in said fluid mass; means for separately removing said materials from said mass af-.

ter they are positioned indifferent zones by reason of their different rates of fall in said mass; means for agitating said fluid mass; and means for causing movement of said fluid-mass in said receptacle. I

9. A method for separating and classifying materials comprising coal, impure coal, bone, slate, and other impurities,-which consists in submerging said materials in a continuously agitated fluid mass comprised of a mixture of water and comminuted granular solids, said solids being of such nature as to remain suspended in a hydraulic current that will not support the materials to be separated by differences in falling velocities, and said fluid mass having a specific gravity less than that of the said materials; in causing the materials to fall in said fluid mass,

whereby the materials of relatively high tinuously agitated fluid mass composed of a mixture of water and sand, said sand being of such nature as to remain suspended in a hydraulic current that will not support the materials to be separated by differences in falling velocities, and said fluid mass having a specific gravity less than that of the said materials; in causing the materials to fall in said fluid mass, whereby the materials of relatively high falling velocity position themselves below the materials of relatively low falling velocity; and in separately removing said materials so positioned from saidfluid mass.

In testimony hands and seals, HENRY M. CHANCE atPhiladelphia, Pennsylvania, on the first day of July, 1918, and THOMAS M. CHANCE at Baltimore, Maryland, on the fifth day of July,

HENRY M. CHANCE. [1 s.] THOMAS M. CHANCE. [1,. s.] 'Witnesses as to Henry M. Chance:

J. H. QUINN, CHAS. BUSH. Witnesses as to Thomas M. Chance:

. RICHARD B. Pun, E. PAUL MASON.

whereof, we have set our

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