US797239A

US797239A - Dry concentrating-table.

Info

Publication number: US797239A
Application number: US13392502A
Authority: US
Inventors: Henry M Sutton; Walter L Steele; Edwin G Steele
Original assignee: Individual
Current assignee: Individual
Priority date: 1902-12-04
Filing date: 1902-12-04
Publication date: 1905-08-15
Anticipated expiration: 1922-08-15

Description

No. 797,239. PATENTED AUG'. l5, 1905. H. MQ SUTTON da W.. L. 61: Gn. STEELE.

DRY CONCENTRATING TABLE..

APPLIOMIQH Hmm MOA, 1902;

i i SHEETS-$113335 1.

- ver" No. 797,239. I PATENTED AUG.. l5, 1905. H. M. SUTTUN L W. L. (Y: E. G. STEELE.

DRY CONGBNTRATING TABLE.

APPLICATION mmm mam, 1992.

No. 797,999. EATENTED A99. 15, 1999. E. M. SUTTON A W. L. E E. E. STEELE.

'DRY GONGENTRATING TABLE.

APPLICATION FILED MUA, 1902.

No. 797,239. PATENTED AUG-.15, 1905.

H. M. SUTTON L W. L. 6a E. G. STEELE.

DRY GONGENTRATING TABLE.

APPLIGATIM Hmm 9120.4, 1902.

. ,fm Afm@ www. a Gummi ccA ,Huvomrnacmw iUNTT'ED STATES PATENT FTTEUE.

HENRY M. SUTTON,

DFH NEN'll'llQATiNlGvffABlhE..

Specification of Letters Patent.

Patented Aug. 15, 1905i.

Application filed December 4, 1902. Serial No. 133,925.

Be it known that we, HENRY M. SUTTON, VALirni-i L. S'rnntn, and EDWIN G. S'rnnnm, citizens of the United States, residing at Dallas, in the county of Dallas, cState of Texas, have invented certain new and useful Improvements in Dry Coneentratiiig-Tables, of which the following is a specification, reference being had therein to the accompanying drawil'igs.

This invention relates to a dry concentrating-table, and particularly to a construction by which a riiiied table is adapted Afor use in dry concentration by the use of air as a floating medium for the material.

The invention has for an object to `provide a dry concentrating-table adapted to operate by an air-pressure in a similar manner to an ordinary wet concentratingtablc, said air for Vfloating thc dry material being passed upward between the rifiies located upon said surface.

A further object of the invention is to provide a pervions transverselysinelincd tabletop having longitudinal rifiies thereon and means for passing' a current of air through said tcp while the table is reciprocated longitudinally.

Another object of the invention is to provide an improved construction of parts for supporting the table to permit a longitudinal reciprocation thereof and also adjusting means to vary the transverse inclination of the table and the longitudinal inclii'lation thereof.

'Other and further objects and advantages of the invention will be hereinafter set forth and the novel features thereof delined by the appended claims.

In the drawings, Figure l is a vertical longitudinal section through the table; Eig. 2, a side elevation thereof from the back of the table; Fig. 3, a vertical cross-section through the table and hopper on line 3 3 of Eig. l; Eig. A, an end view of the driving mechanism; Fig. 5, a detail vertical longitudinal section showing modified means for applying' the air-pressure- Fig. 6 is a vertical cross-secltion on line 6 6 of Fig. 5 through this construction of table for producing an intermittent air-blast; Fig. 7, a detail section showing one of the tapering rifiles. Eig. i5 shows Eig. 9 a plan showing the riffles extending the entire length of the table. Eig. 10 is a similar view showing parallel longitudinal rifdes with advancing terminals, leaving a triangular unriliied space. Fig. 1l is a similar View showing parallel diagonally-disposed riti'les with advancingterminals and an unrifiled space above and below the rif-iles. Eig. 12 is a plan showing the table-top provided with parallel rifiles extending in diiferent planes down a por tion of thc table to form transverse steps, Fig. 13 is an elevation thereof, showing' this stepped arrangement. Eig. 14: is a plan of a further arrangement of rifiles adapted for use with this invention in which a number of longitudinal steps are provided having parallel longitudinal riilles upon cach one thereof. Fig. .1.5 is an elevation of the structure shown in Eig. 14;. Fig. 16 is a plan of a table provided with parallel riflies alternately extended and formed in separated sections. Fig. '17 isa plan of the table having rifiies extending from corner to corner thereof parallel with the direction of vibration and at right angles to the feed, and Eig. i8 is an elevation of a preferred arrangement of the table-support.

Like letters of reference refer to like parts in the several figures of the drawings.

The letter A designates a base or sill of any suitable construction upon which an adjusting-frame B is mounted and adapted to carry upon its upper face the concentratingtable C, above which a feed-hopper D is disposed at one end and supported by any ,suitable 'form of standards, such as shown at A'. The adjusting-frame B is pivotally mounted at one end upon the base A by means of the connec# tion B and is provided at its opposite end with a bracket B2, through which the upper end of a threaded adjusting rod or post li" passes, which rod is provided with a traveling nut Bl thereon, having a suitable handle B5 for rotating the same. The rod B3 is secured at its lower end B to the base, and the traveling nut upon the rod adjusts one end of the frame B so as to vary the longitudinal inclination of the table. The adjusting-rods are disposed upon opposite sides of the table at one end thereof, and the traveling nut B" upop each rod is provided with a sliirocket-wheel l', from which a chain D extends to lthe nut upon the opposite rod.

Upon the adjusting-frame B of the table supports E are disposed and consist of short rods E', having round-head ends adapted to seat in a socket E2 upon the frame B and a similar socket E3 upon the under face of the table at one side thereof, while the rod E' at the opposite side is seated at its upper end in a socket EL upon the under face of the table and at its lower end in a socket E, carried by an adjusting-screw E6, mounted in a threaded bracket E2, suitably secured to the adjusting'- frame B. This screw is provided with a sprocket-wheel F2, from which a chain E2 eX- tends to the adjuster at the opposite end of the frame in order to effect a transverse adjustment of the table. The rods at opposite ends are connected together by a bar El", which causes a simultaneous movement of the bearings in the longitudinal vibration of the table.

The table is provided at its upper portion with a series of parallel slats C', extending' longitudinally thereof to provide air-outlets between the same. These slats may be of any desired cross-scctiongfor instance, tapering upwardly, as shown in Figs. 3 and 6. Resting upon the slats is a pervious top C2, formed of cloth or any desired material adapted to permit the passage of air therethrough under pressure, and upon the upper surface of this pervious top a series of ribs or riiiies G2 is disposed, each of the same being preferably in alinement with the slat C' beneath it and secured thereto in any desired manner. Various arrangements and characters of rifl'les may be used, as will be hereinafter described in connection with the modifications shown in this case; but a preferred form `is illustrated in Fig. 7, where the rifHe tapers downwardly from the hopper end of the table to the discharge end, as shown at C2. The table is normally inclined transversely of its length, which inclination maybe adjusted by the means hereinbeforcdescribed, and a suitable protectingrib (I) is provided at one side and end of the table, while the opposite side is formed with a discharging-ange C andthe discharge end with a similarly-inclined flange Us. If desired, the slats may be supported between their ends by means of crossbars C2, as shown in Fig'. l, and any preferred method of introducing an air-blast beneath the slats may be used, one form being shown in Fig. l, wherein a tapering bottom (J2 of airtight character is provided beneath the slats, and communicating therewith is a feed-pipe F, extending' to a suitable compressing device F', such as a fan, and having abovefits discharge a bafHe-plate F2 to prevent a direct pressure through the table above the discharge from the pipe. This pipe may be of a iiexible character adjacent to its connection with the table, as shown at F2, so as to permita vibration of the table without affecting the relation of the pipe thereto.

The tapering bottom C of the air-chamber i i i i varies the capacity or area thereof at the ends, so as to maintain an equal pressure of air at all points, and also provides means for conducting the tine dust which may pass through the pervious top to a central point, where it may be removed whenever necessary.

For the purpose of imparting a longitudinal reciprocation or vibration to the table a bracket G is secured to the under side at the hopper end thereof and a pitman-rod G' pivotally secured at one end to said bracket and at its opposite end to an adjustable connecting-sleeve G2, having its free end pivotally connected to a crank-arm G3, having' its shaft G4 mounted in a bearing G5 upon the base of the machine. For the purpose of providing a vertical adjustment of the pivoted end of the connecting-sleeve G2, and thus regulating the extent of throw or vibration of the table, an adjusting-screw GG is mounted in the vertical member of the crank-arm and provided at its lower end with a handle G7, while the free end of the connecting-sleeve is pivotally secured to a traveling nut G2 by the pivot-pin G". The horiZontally-disposed end G10 of the crank-arm is provided with an antifrictionroller Gu, disposed beneath an operating-cam H, mounted upon a shaft H', suitably journaled at its opposite ends in standards H2. rThis shaft is provided with a cone drivingpulley H, connected by the belt H'i with a similar oppositely-disposed cone-pulley upon the shaft .f 6, also journaled at its opposite ends in the standards H2. The shaft H is provided at one end with the driving-pulley H7, connected to any suitable source of power, and at its opposite end with a similar pulley Hs, connected by a belt H(J with a drivingpulley H12 upon the end of the shaft D', carrying the feed-roller D2 beneath the hopper. For the purpose of adjusting the belt H* upon the cone-pulleys for regulating the driving speed of the several. parts a belt-shifter I is provided comprising a screw-shaft l', mounted in a bearing I2 u on one standard and )rovided with a loop 12, surrounding the belt, while the free end of the shaft is guided in its movement by means of a supporting-rod lf, carried bythe opposite standards, upon which a collar I is adapted to slide. The reciprocating mechanism for the table is held under proper tension by means of a spring J, extending froni the bracket G to a fixed support J', carried upon the frame B and provided with a connecting-rod J2, having a threaded adjusting-screw J3 mounted in the xed support J' and provided with a hand-wheel J4 for adjusting the tension of the spring to hold the crank-arm in contact with its operating-cam and for restoring the table after its movement' by said cam.

The shaft D' of the feed-roller D2 beneath the hopper D is mounted at its opposite ends in bearings A2, carried upon the standards A', and for the purpose of disconnecting this feedroller from its driving mechanism whenever desired a clutch D3 is slidably keyed upon the shaft D and provided with a handle D", pivoted thereto at D" and pivoted at its lower end in a iixed arm D, extending from one of the bearings A3. The Yfeed-roller Dil is provided with a series of longitudinal recesses or corrugations Dl, which may be of any desired depth or area, depending` upon the feed desired upon the table, and the roller is disposed beneath the opening at the bottom of the hopper. At one side of this opening a flexible strip B8 is disposed to prevent escape of material at the rear of the roller, and uponr the front of the hopper an adjustable discharge gate D" is slidingly mounted and adapted to be adjusted by a hand-wheel Dm, threaded upon the upper end Dlof the operating-rod Vfor the gate and disposed between the arms of the bracket D, as shown in Fig. 3.

ln Figs. 1 and 2 the table-supports l are shown as disposed in a vertical plane extending through the 'frame l) and the table (Il, the result of which causes the table to reciprocate longitudinally and also to descend toward a lower parallel horizontal plane in its movement away from the hopper. VIt has been found very desirable, and preferable in many cases, to incline the supports toward the head or feed end of the table, so that the table rises into a parallel horizontal plane at each forward stroke and returns to the initial plane upon the return stroke. ln Fig. l an arrangement of the parts Yfor accomplishing this object is shown, wherein the supports'E are inclined obliquely to a vertical plane through the table and frame and toward the feed end of the table. lt has also been found preferable in many cases to provide an equal Yforward and return movement instead of the quick forward and slow return secured by the cam H in Figs. l and 2 and the springd coiperating therewith. .in order to secure this equal movement, an eccentric U may be secured upon the-driving-shaft H and surrounded by a strap O', having' a depending arm U2, pivotally connected at its lower end O3 to the crank-arm G by means of the free arm Uw thereof, while the weight of the table is balanced by a spring J, connected to a support J, similar to that shown in Fig-1. The cranlcarm G is similar in construction to that heretofore described, as are the other parts of the table and support, the only differences in construction and arrangement being the diagonal disposition of the supports E and the eccentric connection, whereby the table vibrates backward and forward. longitudinally and is given simultaneously a rising-and-falling movementin a vertical plane. i

The form of air-supply shown in Fig. 1 provides for a constant pressure; but the in- Vention is equally applicable :for use in connection with au intermittent pressure, and for this purpose any desired form of airblast may be used, for instance, as shown in Figs. 5 and 6. The table C may be provided beneath the slats C with an apertured partition K, the opening' therein extending' longitudinally of the table and being provided with upwardlymovable valve-plates K toadmit the passage of air into the chamber beneath the slats and pervious top C, while beneath this partition l( the perforated bottom. plate li of the bellows is disposed and provided with the movable section K, flexibly connected at K" with the stationary portion ofthe bottom. This movable portion K is provided with transverse openings K, having 'valves li above the same and provided upon its under surface with the pivoting-bracket K7, connected to any suitable driving mechanismfor instance, a crank-arm L, similar to that shown in connection with the driving mechanism the horizontal member L of which is connected by a rod L with `the bracket Kvwhile the vertical member is provided with a sleeve L, mounted thereon for longitudinal adjustment. This sleeve is adjustably connected to a pitman L, extending to a boxing L, disposed about a cam L, located upon the driving-shaft lrl/ of the mechanism hereinbefore described. Yln this Vform of table, whereon the ore is `floated or suspended bythe air passing upward through the pervious top, any desired form or arrangement of riliies may be used, and `for the purpose of showing the applicability of a number of Yforms now in use upon washers which are adapted to be disposed upon the pervious table herein used we have illustrated in Fig. 8 a series of longitudinal riiiies M of equal length extending parallel toward the foot of the table and terniinating so as to leave a rectangular unrifiled space NP. lin Fig. 9 a similar arrangement of ril'lles M2 is shown extending the entire length of the table.

Fig. YLO shows the longitudinal riilics M with advancing terminals, leaving a triangular unril'i'yled space M", while Fig. ll shows the riii'les lvl disposed diagonally to the sides of the table with advancing' terminals, leaving an unril'lled space M above and. below the riliies and also at one end thereof.

Fig. 12 illustrates a form of table having steps MT extending transversely in different horizontal planes, the rii'lles his being disposed longitudinally of the table and the unrified space M" provided upon the lowest step. The tendency of the gang-ue in the movement of the table when operating upon very fine material is to Yliow back toward the head of the table, and the stepped arrangement (shown in Fig. 13) prevents this objection.

Fig. 14 is a top plan of a table provided with a number of longitudinal steps N, having' parallel longitudinal riiles N thereon, and for the purpose of allowing the material to be returned toward the head of the table as it passes from one level to the next below the usual chutes or gutters h are provided, as shown in Fig. 15.

In Fig. 16 a table is shown having riifles N3 in separated portions, the alternate riiiies terminating at different lengths, while an unriiiied portion i 4 is provided at one end ofthe table.

In Fig. I7 the riffles N5 extend entirely across the table from one corner to the other, while the vibrations of the table arein line with the riflies and the feed at a right angle thereto.

As before stated, the invention is not conlined to the use of any one of the forms herein shown, they being illustrated for the purpose of demonstrating the adaptability of the table to the different arrangements of the riflies now in use in various forms of concentrators.

The table C is inclined transversely and also longitudinally, the foot or discharge end being slightly higher than the feed or hopper end, thus causing the material to travel upwardly thereon in its movement toward the discharge end of the table. This is essential when operating upon fine ores in order to retard the too rapid travel of the values which would otherwise occur. In other characters of ores and those of larger size mesh itmay be desirable that the table be perfectly flat longitudinally or even slightly lower at the foot end, and the adjusting means applied to the frame for varying the longitudinal inclination of the table is to adapt the same for use with diiferent sizes and grades of ore. The vibrating means for the table herein shown cause the same to be drawn back slowly and returned forward quickly by the tension of the spring; but, if desired, this movement can be completely reversed and an upward or lifting movement may be given the table, if preferred, by adjusting the supports to slope the table toward the head or hopper end thereof. If it be desired to drop the table slightly at each forward stroke, the supports are given a slight inclination toward the foot or discharge end of the table, as shown in Fig. 18, While the length of stroke or travel of the table is adjustable by the hand-wheel and screw operating in the vertical arm of the crank-lever, as shown. The form of this vibrating mechanism herein disclosed is merely intended to illustrate a desirable construction; but the invention is not specifically confined thereto. The ore or material to be concentrated is fed by the roller beneath the hopper upon the head end of the table in predetermined quantities and falls between the tapering riifles upon the upper surface of the pervious top of the table. The air passing' upward through this top stratifies the different minerals, while the longitudinal vibration in connection with the inclination of the table retains this stratification so as to discharge the different results of the concentration at different points upon the table.

The present invention provides a dry concentrator adapted to treat ores in a similar manner to the wet tables heretofore used and to secure a much more efhcient and rapid operation with a minimum loss of the values in the tailings which pass from the table. rIhe separating medium used to float or support the ore being air adapts the invention for use inthe many mining localities where water is often entirely absent, thus rendering a wet separation impracticable and avoiding the necessity of transporting the ore, frequently at a great cost, to a mill or separating plant at a distance from the mine. Furthermore, very often the ores carry matter soluble in water, which either prevents a separation being effected by thickening the pulp, and thus iioating out the values, or the values themselves may be soluble, or partially so, and thus pass over the table in solution. Nothing in ores being soluble in air, it will be apparent that the formation of such a pulp or thickening of a solution which occurs in wet separation is entirely avoided. An ore may carry a value very soft as compared to the gangue or other values, which results in this value being slimed in crushing and floated on the surface of the water. Under certain conditions ores will slime to such an extent as to be impossible of commercial treatment by any wet method, either mechanical or chemical. In the present table any size mesh of material can be treated, however iine. The finer or more packy the material the better results are obtained when a constant pressure of air is used. In the use of water flowing over a table there is a tendency to mix the values and cause loss by washing them off the table. As the water flows over the table it causes eddies and whirls, each disturbing the stratilications on the table, and as the clear water iiows over the clean-up space at the lower end it washes down the strata toward the discharge side, causing them to overlap, with the result that a large portion of the concentrates must bereturned for a further treatment. This water also washes the values which have a tendency to come out high up on the table down toward the discharge side, causing the values to pass off the table within a few inches of the gangue or dross, and considerable loss results from this cause. By introducing the separating medium or air through the pervious table-top there is no whirling or eddying of the ore, which is simply rested or floated on a cushion of air suiiiciently strong to float the gangue, but not strong enough to blow the mass about. The ore being iioated, the motion of the table causes the values to settle to the bottom and stratify, the particles having the greatest speciiic gravity lying upon the bottom against one varese or more of the rifffes. After the stratification of the ore has been effected there is nothing to disturb this, and the mass fiows downward toward the foot end of the table, while the particles reach a portion of the sloping or tapering riffles low enough to allow them to pass over and to arrange themselves in well -delined zones, according to their specific gravity. It will be readily seen that there is nothing' to disturb these zones as they travel across the clean-up or unriffled space at the foot of the table, so that a perfect separation is effected whereby the heaviest and most valuable values will pass ofi'l the table high up on the feed side and away from the gangue or strata of lesser specific gravity and value. Attention is also called to the fact that the use of air, being a much lighter medium than water, causes the particles of ore being separated to have a greater effective weight in a lighter medium than a heavier. A particle of mineral when suspended in water displaces a greater weight thereof than of air, and the apparent weight of the mineral is less than when in air, so that the difference in effective weight between the mineral and gangue is considerablyless when immersed in water than when in air, thus making it possible to separate particles of nearer the same specific gravity in air than in water. Also the natural cohesive force is the same in water as in air, and with the lessened effective weight in water between the particles the more difficult it is for the water to break this cohesive effect and separate the values from the gangue, while the action may be readily accomplished in the air-separating medium. This use of air also permits the use of the invention in very cold climates, as there is no medium used in the concentration which could freeze and interfere with the action of the device. Another serious defect experienced in wet concentrating-tables having a blank or un'riff'led space at the foot end is when the ore mass reaches this space, it is greatly reduced in bulk, passing' over the same in a very thin layer, and in order not to wash this layer of thin material down into the waste material the water must be handled very carefully and must `fiow very evenly over the ore. This is very difficult to accomplish, and as the result the water frequently does not cover the entire layer of ore, but runs in streams and streaks across the table, changing its course when obstructed by a mass of ore or by a change in the feed or water supply. The portions of ore left uncovered by the wash-water quickly dry and are floated away when next brought in contact with the water, as it .is almost impossible to sink very line dry ore in water. In dry ore-concentrators it has heretofore been very difficult to effect a very satisfactory separation, as no efficient means have been provided to secure a stratification of the mass and the subsequent separation of the strata.

Among the important features by which the efficient action of the present invention is secured and the difficulties in the prior art obviated is the pervious top through which the air passes to cause the ore to stratify, the riflies upon said top by which the gradual separation of the strata can be effected, and the longitudinal vibration which causes the material to travel from the head to the foot of the table.

A further important feature is the use of the tapering' riflles upon a dry concentratingtable having a pervious top, said riffles being either of advancing terminals or otherwise arranged. lt will therefore be obvious that changes may be made in the details of construction and configuration without departing` from the spirit of the invention as defined by the appended claims.

lffaving described our invention and set forth its merits, whatwe claim, and desire to secure by Letters Patent, isw

l. The combination of an inclined pervious 'fioor having its surface provided with longitudinally-disposed riffies, means for maintaining successive zones of separated material, and means for maintaining beneath the floor a uniform upward pressure of air through the pervious fioor and the material upon it.

2. f lhe combination of an inclined pervious fioor having' its surface provided with rifiies and an unrifiied plain space at their discharge ends, and means for maintaining beneath the floor a uniform upward pressure of air through the pervious floor and the material upon it.

3. rlhe combination of a pervious inclined fioor having its surface provided with longitudinally-disposed riffles, means for maintaining an upward pressure of air through the pervious floor, means for causing the spread and travel over it of granular or pulverulent material, and means for maintaining a stratification of the particles and for causing said strata to emerge beyond the mass as successive zones and for maintaining the graduation of the particles at the delivery portion of the floor.

4. The combination of a pervious floor having part of its surface divided into longitudinal channels, i'neans foiI causing the spread and travel over it of granular or pulverulent material, means for maintaining a stratification of the particles and for causing said. strata to emerge beyond the mass and channeled surface as successive Zones and for maintaining said zones, and means for maintaining an upward pressure of air through the pervious floor and the material upon it.

ln a dry concentrator, the combination of a pervious inclined floor provided upon its upper surface with longitudinal riffles and a substantially unriffled portion, with means for maintaining an upward uniform pressure of air through the pervious floor and thematerial thereon, and means for feeding saidV material relative to said riffles.

6. In a dry concentrator, the combination of a pervious inclined floor provided upon its upper surface with longitudinal riifles and a Substantially unrilfled portion, with means for maintaining an upward uniform pressure of air through the pervious `floor and the material thereon, and means for longitudinally vibrating said floor substantially parallel to the riflies thereon.

7. In a dry concentrator, the combination of a pervious inclined floor provided upon its upper surface with longitudinal rifiles and a substantially unrifiied portion, with means for maintaining an upward uniform pressure of air through the pervious floor and the material thereon, means for longitudinally vibrating said door substantially parallel to the riffies thereon, means for adjusting the transverse inclination of said floor, and means for longitudinally inclining said floor.

8. In a dry concentrating-table, a pervious floor, means for maintaining` an upward pressure of air through said iioor and the material thereon,rifles extending longitudinally of said floor and diminishing in height toward the discharge end thereof where they terminate at different distances relative to a line transversely of the floor, and means for producing a feed of material upon said table.

9. In a dry concentrating-table, a pervious floor, means for maintaining an upward pressure of air through saidfloor and the material thereon, rifiies extending' longitudinally of said floor and diminishing in height toward thc discharge end thereof where they terminate at dierent distances relative to a linc transversely of the floor, and means for longitudinally vibrating said iioor.

l0. In a dry concentrating-table, a riflied pervious floor, means for feeding material upon said table, means for maintaining an upward pressure of air through said fioor and the material thereon, an air-chamber beneath said floor having a bottom inclined upwardly toward each end of the table, and an air connection disposed centrally of said bottom.

ll. The combination of an inclined pervious floor having its surface provided with longitudinal riflles and means for maintaining' zones of separated material at the delivery ends thereof, means for maintaining an upward pressure of air through the pervious ioor and the material upon it, and an oscillating snpport for said Hoor to permit the rising and descending movement in the vibration thereof.

12. The combination of an inclined pervious floor having' its surface provided with longitu dinal rifiics and means for maintaining' zones of separated material at the delivery ends thereof, means for maintaining an upward pressure of air through the pervious floor and the material upon it, and an oscillating' support for said floor constructed and arranged to produce a rising' movement thereof during the forward stroke toward the discharge end and a descending movement in the return stroke toward the feed end thereof.

13. The combination of an inclined pervious iioor having its surface provided with longitudinal rifiles and means for maintaining zones of separated material at the delivery ends thereof, means for maintaining an ugward pressure of air through the pervious floor and the material upon it, a frame beneath said licor, a supporting member having' a pivot-al hearing' in said frame and floor and disposed obliquely toward the feed end of the table, and means for imparting' a reciprocatory movement to said table.

In testimony whereof we afiX our signatures in presence of two witnesses.

HENRY M. SUTON.

IV ALTER L. STEELE.

EDIVIN G. STEELE.

IVitn ess es:

OLIvER V. STEELE, JAMES F. DAvIEs.