US2720971A - Gravity separation apparatus - Google Patents

Description

Oct. 18, 1955 w. L. ROLLER GRAVITY SEPARATION APPARATUS Filed July 30, 1952 4 Sheets-Sheet l INVENTOR. WILFERD L. ROLLER ATTORNEY Oct. 18, 1955 w. L. ROLLER GRAVITY SEPARATION APPARATUS 4 Sheets-Sheet 2 Filed July 30, 1952 WILFERD L. ROLLER 2 ATTORNEY Oct. 18, 1955 w. L. ROLLER GRAVITY SEPARATION APPARATUS 4 Sheets-Sheet 3 Filed July 30, 1952 INVENTOR. WILFERD L. ROLLER B BY ATTORNEY Oct. 18, 1955 w. L. ROLLER GRAVITY SEPARATION APPARATUS 4 Sheets-Sheet 4 Filed July 30, 1952 O O m m o m 3 m h M 300 00 520 &0

BE 3E m m N N m R W1 m a m A Y B 3 0 520 8m.

GRAVITY SEPARATION APPARATUS Wilferd L. Roller, Hazleton, Pa., assignor to Wilmot Engineering Company, a corporation of Pennsylvania Application July 30, 1952, Serial No. 301,680

6 Claims. (Cl. 209-172) This invention relates generally to improvements in apparatus for gravity separation of components of different specific gravity from a mixture of such components through the agency of a liquid separating medium of specific gravity intermediate that of the components to be separated. More particularly, the invention relates to gravity separation apparatus wherein the separating medium enters the apparatus from two directions perpendicular to one another, the medium entering from one direction producing a horizontal current in the apparatus for conveying the floating particles to a discharge therefor, and the medium entering from the other direction severing the twofold purpose of maintaining the medium in the apparatus at constant density while also lifting to the level of the aforesaid discharge any li -ht particles that may have been entrapped among the sink components and carried downward thereby.

t is therefore a primary object of the invention to provide an apparatus for the gravity separation of mineral components of different specific gravity from the mixture containing such components.

Another object is to provide apparatus for the above purpose capable of separating minerals without regard to the size of the particles.

A further object is to provide apparatus for the above purpose wherein a horizontal movement of the liquid separating medium is maintained to convey the floating particles to a discharge weir or port therefor, and wherein a portion of the liquid separating medium is introduced into the apparatus at the bottom and caused to pass upwardly through the heavy sink material as the latter is moved along the bottom of the apparatus, whereby any light floatable material that may have been entrapped by the sink material will be raised and discharged with the light components of the mixture.

An additional object is to provide apparatus of the above description including a flight conveyor for the removal of sink material, wherein the conveyor is returned to the separating vessel by means of a well separated from the vessel so that movement of the conveyor will not disturb the separation proceeding in the vessel.

A still further object of the invention is to provide apparatus of the above description which is capable of simultaneously treating several raw feed mixtures of different particle sizes and separately discharging float material of the several particle sizes.

In order that the invention may be readily understood and its practical advantages fully appreciated, reference may be had to the accompanying drawings in which I have illustrated apparatus constructed in accordance with and embodying the principles of the invention. In the drawings:

ig. l is an end elevation view of a preferred form of gravity separation apparatus embodying the invention, portions thereof being shown broken away for clearer illustration of the chute and weir details;

Fig. 2 is a side elevation view with portions of the Fig. 3 is a plan view of the apparatus with the conveyor mechanism and hood removed;

Fig. 4 is a sectional view taken along the line 44 of Fig. 2;

Fig. 5 is a plan view similar to Fig. 3 showing battles subdividing the tank longitudinally into several sections, with separate feed chutes for introducing raw feed independently into such sections;

Fig. 6 is a vertical sectional view taken along line 6-6 of Fig. 5; and

Figs. 7, 8 and 9 are diagrammatic plan views similar to Fig. 3 showing modifications of the gravity separation apparatus of the invention.

In the embodiment illustrated in the drawings, the apparatus comprises a tank 10 of generally rectangular form in plan (Fig. 3), two opposite walls 11, 12 of which may be vertical for a portion of their height and preferably steeply sloped inwardly of the tank as they approach the bottom 13. The other walls 14, 16 of the tank may be vertical for their entire height. A well 17 projects outwardly from the wall 14, and a conveyor compartment 18, having an upwardly sloping floor 19, projects outwardly from the opposite wall 16 of the tank, both the wel i7 and compartment 18 communicating with the tank it) as will appear hereinafter.

Two pairs of idler wheels 20, 20 and 21, 21 for a conveyor chain are positioned respectively near the bottom of the well 17 and the tank 10, idlers 20, 20 being rotatably mounted on a shaft 22 journaled in bearings 23 in the side walls of the well 17, and idlers 21, 21 being rotatably mounted on a shaft 24 journaled in bearings 26 in the walls 11 and 12 of the tank 10. Two pairs of sprockets 27, 27 and 28, 28 are rotatably mounted on shafts 29 and 3t) journaled respectively in bearings 31 and 32 carried by the sides of the conveyor hood to be described. An endless chain 33 carrying a plurality of perforated conveyor flights 34 is threaded on the sprockets and idlers, as shown, and is driven by any convenient means in a closed path across the bottom of the tank 19, diagonally upwardly along the bottom of the conveyor compartment 18, reversedly across the top of the tank and downwardly through the well 17 to the bottom of the tank. Preferably a hood 36 is provided for the upper course of the conveyor, and the hood may have removable covers (not shown) conveniently placed to permit access to the conveyor for any purpose.

The conveyor drive means illustrated comprises a motor 37 which drives a sprocket 38 through a speed reducer 39, the sprocket 33 being connected by means of a chain id to a sprocket 41 fixed to the shaft 30 previously described. The upper course of the chain conveyor rests upon rails 42 supported by transverse channel members 43 fixed at their ends to the hood 35. Wear shoes 44 are provided on the flights 34 to receive the wear resulting from frictional contact of the conveyor with the rails 42.

In order to keep floating material from entering the well 17 a baflle 46, formed from the central portion of the wall 14, extends across the side of the well adjacent the tank 10 and is continuous from the top of the tank to a point adjacent the sprocket 20 at the bottom of the well. To prevent wear of the apparatus by the friction resulting from removal of the heavy sink components therefrom, wear plates 47, approximating the contour of the flights 34, are fixed to the floor of the well 17, tank it and conveyor compartment 18.

The upper part of the wall 11 is cut away for a portion of its height to provide an opening 48 into the tank 10 for a feed chute 49 which is fixed to the wall 11 by any suitable means. A weir 50 is formed in the upper part of the wall 12 opposite the chute 49 for the discharge of float material introduced by the raw feed. A structural cross member 51 constituting a continuation of the top edge of the tank is provided to assure that the strength and rigidity thereof is maintained in the vicinity of the weir.

Depending from the upper edge of the tank and extending across the feed chute, is a baflle 52 which projects downwardly to the level of the liquid separating medium determined by the weir 50. The baflie 52 greatly strengthens the tank adjacent the opening 48, but its primary purpose is to assure that all raw feed introduced by the chute 49 is immediately submerged in the liquid medium, wherel by all components thereof are quickly wetted and an the preferred use of the present apparatus, most of the liquid medium used therein is introduced by means of the pipes 53, and the discharge therefrom sets up and main- 7 tains a steady horizontal flow or current at and adjacent the liquid level in the direction of the weir. The pipes 53, each of which is provided with a valve 54, are fed by a manifold or header 56 which is kept constantly supplied with liquid medium by a pump (not shown) connected to the conventional sump (not shown) employed to recover and recirculate the liquid separating medium through the apparatus.

The bottom of the tank 10 is apertured, as at 57, afi'ording ingress to the tank 10 of an additional amount of liquid separating medium, and a grid 58, comprising a plurality of spaced'bars 59, is positioned over the opening 57 to prevent the entry thereto of heavy sink components of the feed. The separating liquid inlet which registers with the opening 57 is preferably in the form of an inverted cone or pyramid 60 connected to a supply pipe 61 which preferably communicates with the pump and sump previously described. A valve 62 controls the flow'of liquid medium through the pipe 61.

At the end of the conveyor compartment 18 is a discharge chute 63 for sink material removed from the bottom of the tank by the' conveyor, and adjacent the chute 63, and inwardly thereof, is a drain grid or screen 64 in the floor of the conveyor compartment to remove any liquid carried out of the tank 10 by the conveyor.

Beneath the screen 64 is a drain pan 65 provided with a pipe 66 leading to the aforementioned sump for recirculation of 'the separating medium recovered through the screen 64. 7

Within the conveyor compartment adjacent to and in communication with the tank 10 is a cell 67 defined by perforated walls 68, 69, 70 and 71 extending between the sidewalls of the conveyor compartment 18. The cell 67'is open at the top, and the bottom walls 70 and 71 are spaced above the floor of the conveyor compartment to permit passage of the conveyor. The perforations in the walls of cell 67 permit the separating medium to circulate freely through the cell but are small enough to exclude substantially the solid components of the feed being treated, thereby isolating within the tank a portion of the liquid separating medium on which the specific gravity determinations may be accurately made. Q In operating the apparatus above described, the tank 10 is first filledwith liquid separating medium to a depth determined by the weir 50, and the motor 37 is operated to move 'thechain conveyor in its closed path defined by the sprockets 27, 28 and idlers 20, 21. The input of liquid medium is controlled by adjustment of valves 54 for the horizontal flow across the top of the tank, and valve 62 for the upward flow from the bottom through the grid 58. For cleaning run-of-mine anthracite I have found that best results are obtained by admitting about 4 70% of the liquid medium through the pipes 53 and about 30% through the lower inlet 60.

Raw feed material, for example run-of-mine anthracite, is now admitted to the tank 10 by means of the chute 49. The feed components are caused by the baffle 52 immediately to be submerged in the liquid, whereby all the particles thereof are quickly wetted and gravity separation begins immediately. The flow of liquid from the pipes 53 carries the float material quickly to the discharge weir 59 where it is recovered on a screen (not shown). The sink material collects on the grid 58 at the bottom of the tank and is removed therefrom by the flights 34 of the conveyor and carried up the conveyor compartment 18 to be discharged through the sink di"- charge chute 63. Surplus liquid carried upwardly by the conveyor rains through the screen 64 into the pan 65 and is returned by pipe 66 to the sump for recirculation through the tank.

Any float material entrapped by the sink components and carried therewith to'the tank bottom will be extricated therefrom by the combined action of the conveyor movement and the slowly rising stream of liquid separating medium from the liquid supply inlet 6% and refloated. The upwardly divergent form of the inlet 69 distributes the liquid flow from pipe 61 over substantially the entire area of the bottom of the tank 10 so that it may lift the entrapped float particles free of the collected sink mate rial. Where the liquid separating medium is of the type in which the specific gravity is determined by the proportion of finely divided solid particles in suspension therein, the rising current from the inlet 60 serves the additional function of maintaining the specific gravity of the liquid substantially constant in all parts of the tank by overcoming the effects of settling of the solid particles.

Where raw feeds of several different sizes are to be cleaned simultaneously, the apparatus may be modified as shown diagrammatically in Figs. 5 and 6. In this modification the separation tank 10 is divided into longi tudinal sections by any desired number of vertical baflles 72 extending from the chute end of the tank to the weir. The baffles 72 project above the liquid level preferably to about the top of the tank, and extend below the liquid level preferably to a point closely above the tops of the idlers 20 and 21. Separate raw feed chutes 49 are provided to introduce the several different sized raw feed materials into their respective sections of the tank defined by the baffles 72; Also, separate liquid inlet pipes 53' from the header 56', controlled by valves 54, are provided to produce the desired horizontal flow of liquid medium in each tank section. Each such section then operates in the same manner as did the apparatus described above, and the float materials discharged at the weir are separately collected and stored. The sink material from all sections of the tank collects on the tank bottom and is removed by the conveyor as previously described. Thus, it will be apparent that this modification of my apparatus is useful only when it is the float materials of the several different raw feeds simultaneously treated that are desired to be collected separately, the sink products from all such raw feeds collecting as a confused mass at the bottom of the tank.

The forms of my apparatus shown diagrammatically in Figs. 7, 8 and 9 require no explanation and have been included in the drawings primarily to illustrate a few of the modifications of structure and operation of which my gravity separator'is capable. It will be understood, therefore, that the invention is not intended to be limited to the precise form and arrangement of parts disclosed, but, rather, to embrace other forms and arrangements so long as they come within the scope of the appended claims.

What I desire to claim is:

l. A gravity separation apparatus including a tank wherein light components of a raw feed are adapted to be floated in a liquid medium and removed through a'discharge opening at one side of said tank and heavy components of the feed are adapted to be removed from the bottom thereof, a supply conduit for said medium adapted to introduce said medium substantially horizontally into said tank in the direction of said opening and below and adjacent the surface of the medium in the tank as determined by said opening, whereby a current of said medium is maintained at and adjacent the surface thereof in the direction of said opening, a second conduit for introducing a further supply of said medium vertically into said tank from the bottom thereof, at least one vertical baflie dividing said tank into several sections extending in the direction of said current, said bafile being adapted to project above the surface of said medium and to extend below said surface a distance suflicient to prevent inter-mixing of the float materials in the said several tank sections, and a chute to supply raw feed separately to each of said sections adjacent said first mentioned supply conduit.

2. A gravity separation apparatus comprising a tank for containing a liquid separating medium, a chute for conducting a raw feed mixture into said tank at one side thereof, a discharge weir for float components of said feed on the side of said tank opposite said chute, a supply conduit for said medium disposed below and adjacent a horizontal plane passing through the discharge lip of said weir, said supply conduit being and adapted to introduce said medium substantially horizontally into said tank adjacent said chute and in the direction of said weir, a second conduit for introducing a further supply of said medium vertically into said tank from the bottom thereof, a grid covering said second conduit for preventing entrance thereto of heavy sink components of said feed, and means for removing said sink components from the bottom of said tank.

3. A gravity separation apparatus comprising a tank for containing a liquid separating medium, a discharge weir for float material at one side of said tank, said weir determining the surface of said medium in said tank during operation of said apparatus, a feed chute for introducing raw feed material into said tank at said medium surface and adjacent the side of said tank opposite said weir, a supply conduit for said medium adapted to introduce said medium substantially horizontally into said tank below and adjacent said medium surface for producing a current of said medium at said medium surface in the direction of said weir, an upwardly divergent inlet for liquid separating medium opening into the bottom of said tank, a grid over said inlet for preventing entrance thereto of heavy sink components of said feed, said tank having a sloping side to conduct said sink components to the area covered by said grid, and conveyor means for removing said sink components from said area.

4. Apparatus in accordance with claim 3 wherein said supply conduit projects horizontally through said chute :below the surface of said medium and in the direction of said weir.

5. Apparatus in accordance with claim 3 including a conveyor compartment extending diagonally upwardly from the bottom of said tank and communicating therewith, and a conveyor well integral with said tank at the side thereof opposite said compartment, said well being open at the top and communicating with said tank at the bottom thereof, said conveyor being movable in a closed path across the bottom of said tank, diagonally upwardly along the bottom of said compartment, reversedly across the top of said tank and downwardly through said well to the bottom of said tank.

6. A gravity separation apparatus comprising a tank for containing a liquid separating medium, a discharge weir for float material at one side of said tank, said weir determining the surface of said medium in said tank during operation of said apparatus, a plurality of supply conduits for said medium adapted to introduce said medium substantially horizontally into said tank from the side thereof opposite said weir below and adjacent said medium surface, whereby a current of said medium at the surface thereof is maintained in the direction of said weir, at least one vertical baflie dividing said tank into several sections extending in the direction of said current, at least one of said conduits communicating with each of said sections, a plurality of chutes to supply raw feed material separately to said sections adjacent said conduits respectively, said baflie being adapted to project above said medium surface and to extend below said medium surface a distance sufiicient to prevent intermixing of the float materials in the said several sections, an additional supply conduit for liquid separating medium opening perpendicularly into the bottom of said tank, a grid over said additional supply conduit for preventing entrance thereto of heavy sink components of said feed, and means for removing said sink components from the bottom of said tank.

References Cited in the file of this patent UNITED STATES PATENTS

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