US2269307A - Method of and apparatus for separating composite material into its components - Google Patents

Description

3 Sheets-Sheet l J. H. DICKERSON METHOD OF AND APPARATUS FOR SEPARATING COMPOSITE MATERIAL INTO ITS COMPONENTS Jan. 6; "1942;

Filed Jan. 28, 1958 Jan. 6, 1942. H DICKERSQN 2,269,307

METHOD OF AND APPARATUS FOR SEPARATING COMPOSITE MATERIAL INTO ITS COMPONENTS Filed Jan. 28, 1958 3 Sheets-$heet 2 Jan. 6, 1942. J. H. DICKERSON 2,269,307

- METHOD. OF AND APPARATUS FOR SEPARATING COMPOSITE MATERIAL INTO ITS COMPONENTS Filed Jan. 28, 1938 3 Sheets-Sheet 5 Patented Jan. 6, 1942 UNITED PATENT OFFICE,

names or AND-APPARATUS FOR SEPA- RATING GOMPOSITE MATERIAL INTO ITS COMPONENTS has a. met-eras, New Philadelphia, om Application-thwart 28, 1938, Serial No. 187,538 15 "claim. 7 (01. 209- 167) This invention relates to pneumatic separators for granularor lump material adapted totsc'parate materials having .difier'e'n-t specific gravities, such' as for separating coal from slate and other refuse. 1 K

More particularly the invention-relates to im provements in the separating 'means and the process of separat'ionidesoribed and illustrated in my Patents Nos. 2,022,588 dated November '26, 1935; 2,033,690 dated March1936; and in my co' pendi'ng' application for patent Serial no. 38,105 filed on August 27 1935, now Patent No. 2,128,918, dated September 6, 1938.

Separators of this kind have a per'vious reciprocating deck sloping to one side on which the bed of material being treated is partially supported above the deck by upward currents of air from below and the vibrations of the deck, caused by rocker arms and the reciprocating drive. "The raw material is fed along the upper side of the deck, and the products are discharged along the ondary deck, thus obtaining more eflicient cleaning over a greater size range on one machine.

A secondimportant-object is to check the discharge of the larger coal with the refuse.

A third important object is to remove more of i the smaller refuse, by removing it separately from the sides of the rifiies along which the coarser refuse moves forwardly.

' A fourth important object is an improved rifiie and stop to assist in the support of the bed of coal over thedeck, and in'the forward movement of refuse on the deck at an angle to the flow of clean coal. I

With the above and other objects in view the invention consists in a novel method of the kind described, and'of apparatus including novel details of construction and combination of parts, both the method and apparatus being hereinafter described, and particularly pointed out in the cIaims, the apparatus being illustrated in the accompanying drawings wherein like characters lower side and the forward end of the deck. in j the ordinary operation of a, machine of type the smaller lighter gravity material is mostly discharged near the rear end of the deckand the larger lighter gravity material tends to move for- Wardly, so the discharge of theli'ghter gravity material becomes gradually coarser towards the forward end of the table. A I V A In the use of a primary separator sufficientair is used to carry the larger pieces of light gravity material'over diagonalri'files', while the larger pieces of heavyg'ravity material drop tothe deck and are directed by the 'riffi'es and the action of the deck :at an angle to the How of material passing over the rifiles'. This separates the coarser heavy 'g'rav'i ty material from the mass, but much of the smaller heavy gravity'rnateri'al is blown Over the rifile's with th li ghti' gravity material. It has been the custom to screen the latter and re-treat the smaller size components, which still contain heavyand light gravity ma terial, on another scpai'ator with reduced air currents, but. this; means extra scre ns, chutes,

conveyors, bins; feeders, motors and more space,

to the deck of the secondarydeckforre-treatment under different conditions, and discharging the larger cleaner material ffurtherforward' to a erviou-s plate, above the cleaning area of the 'sec- 35 of reference indicate like parts in the several views, and:

Figure 1 is a plan view of one form of separator constructed in accordance with this inven tion.

Figure 2 is a section and part view on the line 2-1 of Figure 1.

Figure '3 is a section of the deck showing an improved type of rifiie. 1 Figure4 is a section through the feed. device, which also shows 'a vertical curve in the deck.

Figure 5 is another form of the feed device.

Figure 6 is a section through the deck showing a front view of the feeder parts in- Figure 5.

' Figure 7 is a section through the banking bar concentrator plate arrangement.

Figure 8 is a section and front view of Figure '7.

Figure 9 is a-section of the deck showing differ- 'ent types of rifiles, and means to keep the refuse from slipping. I

Figure 10 is a plan view of Figure 9.

Figure 11 is a section of a special type of riilie.

Figure 1'? is a plan of gate plate in Figure 16.

Figure 18 shows an end View of an inclined deflector.

Figure 19 is a section through the deck giving a front view of the laterally inclined deflector in Figure 18.

Figure 20 is an enlarged plan view showing the refuse end of the table.

Figure 21 is an elevation of Figure 20.

Figure 22 is a rear view of pipes for the feeder.

Figure 23 is a sectional view on line 23-23, Fig.

Figure 24 is a plan of an alternate arrangement of the forward part of the secondary deck B.

In considering this invention, it will be described and claimed with particular reference to a coal cleaner for separating coal from refuse such as slate of greater specific gravity. It is, however, to be understood that neither the method nor the apparatus is restricted to this particular use but both method and apparatus are for separating a mixture having components of different specific gravities whereof coal is typical of a lighter material and slate of a heavier material. It is accordingly to be understood that wherever coal is used, in these specifications and the claims, it is to be interpreted in its broad sense as indicating the light components of a mixture, and refuse and slate are to be taken as referring to the heavier component of such a mixture.

In the embodiment of this invention as herein disclosed there is provided a surge bin I to hold a supply of raw material for the separator. A reciprocating feed plate 2 is one method of supplying a uniform feed to the cleaner. It may move with the cleaner or separately. A gate plate 3 is used with the feed plate to form the feed opening. The separator has a frame or sides 4. a deck 5 with openings 5a, and rifiles B. Other forms of rifiies are shown as ta, 6b, 6c, 6d, and Be. The banking bar 1 is shown with its component parts, a spreader plate 8 and a concentrator plate 9. Gates ill and Illa are used to make a line of separation in the streams of refuse and middlings. Coal is discharged from the deck sections A and B over tailing rifiies II and discharge plates i2. A cut is made between middlings and clean coal by some form of adjustable divider l3. Slate is discharged over chute 14, while middlings go to the hopper l5 and clean coal to the hopper iii. A pervious reciprocating plate I? is attached above the deck 5 on section B to carry the coarser material delivered by section A. In the ordinary operation of a deck section such as A the smaller material of lighter gravity is discharged first and the material becomes gradually coarser towards the front end of the deck. An adjustable section Ila is pro-' vided to regulate the amount of material going to the plate H, which has holes l'lc for the escape of air coming up through the deck below. The plate may have an inclined section l'lb A combination deflector and banking bar 1a confines the large refuse from the upper deck, while finer refuse may bank against the other side. The coarse refuse is lowered part way to the lower deck by the plate 11), and refuse along the upper side of section B may pass through the opening and under the plate 1b, so the main stream of finer refuse will be covered by the coarser refuse, and not have to push against the latter. The air chest I8 is merely indicated. The air chest divisions lSa and 181) are fed from a common air supply with gates to each section. The air supply and gates are not shown as they are not a part of this invention and are well known. Air is thus adjusted to different sections. Support angles l9a working in guides I9 support rocker arms 2| which are adjusted vertically by small jacks of conventional design. Eccentrics 22, eccentric rods 22a, and shaft 22b are driven by any common means from motor 23. Springs 24 are used to facilitate the forward movement of material and steady the deck. Middling chutes 25 may be arranged as desired. An elevator 26 may be used if it is desired to put middlings back on the-deck or in the surge bin. A wedge shaped bar 21 is provided along the deck close to the concentrator plate 9 as a wearing strip and to start the material upward along the vertical curve in the concentrator plate.

For the feeder an air pipe 28 connects with the air chest [8, or any other source of air supply, such as hot air, and supplies air to the pipe 29. The air is controlled by a regulator 30. The member 28a may be flexible when it is attached to a stationary pipe.- Air from the pipe 29 is discharged from the nozzle 3| across the stream of raw coal as it drops to the deck. This floats the lighter material forward where it will drop.

on top of the bed of material over the deck, while the heavier gravity material 34 will tend to drop more nearly the vertical, thus a partial separation is made before the material reaches the deck. Bolts 32 may be used to adjust the width of the opening in the nozzle 3|. As the distance between the feed plate 2 and the deck 5 is not always constant a flexible coupling 33 is provided to keep air from blowing outwardly behind the feeder and to direct it across the feed stream. A housing 4, 33, and 35 may be provided instead of the pipes 28, 29 and the nozzle 3|. The members 4, 33, and 35 form a seal so that most of the air rising through the openings 5a in this part of the deck is forced to pass laterally across the feed stream.

A laterally inclined deflector 36 is placed across a series of riffies where desired. It is supported by brackets 31 and may be adjusted vertically by the bolts 38 working in slots 39. The 1 curved concentrator plate 9 is attached to members 40 having bolts 4! with thumb nuts 42 against bearing plates 42a, Riflies 60 have openings 43 along their tops. The I'iffles 6a are short members which cause the refuse to move in and out from the upper side of the deck. Rivets 44 set in the deck 5 have their front edge clipped to form a stop to keep material from slipping backward. Projections 45 are attached to the riflies Be and are used with or without the rivet stops for the same purpose. The bar or pipe 46 with the straps 48 and thecastings 49- form a seat hinge for the support of the deck frame, which permits the raising or lowering of the sides by screws or jacks 20 working in the guide and supporting framework, The casting is locked to the pipe 46 by the screws 41, and the casting 50 is the bearing for the toggles 2| carrying the machine. They may be set on'the members I 9 or on any suitable support.

The velocity of air on a section of deck along the lower. side of a separator. may be'reduced by increased resistance 52, as indicated in Figure 16, or by any common means. At the end of said section a row of holes or slots 53a are made in the flat deck, or the deck is depressed to a valley 5| at an angle to the direction of the riflles. Below the openings 53a or at the-bottom ofthis valley there may be a pipe or passageway 53 which stratum. This will causea-thickening of the bed just back of the deflector. "Theinclined surface will help to support the material against it, and make it move more readily by'gravity and the deck movement to the lower end of the separator. Refuse banked against the deflector may work down and pass under it, while coal may be pushed across the top of the deflector when it banks sufficiently. When the large coal drops over the top of the deflector, instead of following it to its lower end, the air currents still have a better chance to pick up the coal and help it over the riflles to the lower side of the deck, than'if it had not been lifted by the deflector. Ahead of the deflector the bed of material on the deck will be lighter and theriflies lower so the air will have a further chance to raise the coal and permit it to pass by gravity to the lower side of the separator.

In an ordinary separator the air used to carry the larger pieces of coal over the 'riflles is also suflicient to carry much of the small refuse, and only the heavier gravityrefuse of small size is discharged with the refuse. To correct this the quantity of air is reduced on a section of deck along the lower rear part of the deck. At the forward end of this section the deck is depressed in a valley below and lateral to the direction of the riffles, so that refuse leaves the sides of the rifiies and enters this valley. At the bottom of the valley there is an opening controlled by a gate through which small refuse may go to the pipe or passageway 53, which conveys it laterally below the deck, and then forwardly below the deck to the point of main refuse discharge. This shortens the distance refuse has to travel along the riffles, and saves small refuse from being discharged further forward with the coal. Refuse too large to pass under the rifiles, or into the pipe below the deck, will pass forward in the regular way to the end of the riffles. Another means would be to put holes of the size desired in the flat deck directly over the pipe or passageway.

The downwardly projecting tops of the rifiles 60 help the air and the deck motion to support the bed of coal above the deck. It is especially desirable where the larger refuse has first been removed from the mass, and it is desired to retreat the mass with a minimum of air to remove the smaller refuse. With stops placed above a flat perforated deck the sheets may be slightly thicker than can be used where the sheets are stamped with a waved surface. The holesare distorted by the stamping and the sheets break easily along the lines stamped. Waved sheets can be laid only in one direction. The deck wears out first along the banking bar, but a stamped sheet can not be laid parallel to it, so .a new deck is usually installed. The flat sheets will reduce maintenance, and keep a better deck surface.

A means of adjusting the deck vertically is shown in Figures 12 and 13, but other means may be used. The rear pair of toggles being set more nearly the vertical than those forward give the forward part of the deck a greater vertical movement. j

There has thus been provided a simple and efficient device of the kind described and for the purpose specified. It is obvious that changes may be made in the apparatus and method herein set forth without departing from the material principles of the invention. .It is, therefore, to be understood that the invention includes any apparatus and method which'comes within the:

scope of the appended claims.

Having described my invention and set forth its merits what I. claim and desire to secure by Letters Patent is:

1. In a separator for separating coal from refuse, a primary inclined reciprocable separating deck for removing heavier refuse from raw coal, a secondary inclined separating deck receiving the partially cleaned coal from the primary deck and separating additional refuse therefrom, riffles on said decks arranged at an angle to the direction of reciprocation, each of said decks being provided with a multiplicity of air jet apertures, means to supply air to said apertures, means to control the flow of air through the apertures to provide relatively high pressure air to v the primary deck and relatively low pressure air to the secondary deck, means to reciprocate said decks, and a plate above the cleaning area of the secondary deck to carry the coarser part of the treated coal, being separated from the smaller 'material by the ordinary action of the primary deck, said plate to discharge its treated coal to the lower forward part of. the said secondary and to separate additional refuse from the coal,

said decks being pervious and having riflles at an angle to the direction of reciprocation, means to supply air through said pervious decks, means to adjust the supply of air to different sections of at least one of said decks, a passageway for refuse at thev upper side of said secondary. deck, and rilfies on the forward part of said secondary deck projecting laterally and having their tops set approximately vertical'to the surface of the deck and inclined upward in the direction of movement of the upper stratum of the bed of material on the deck, to'assist the air in lifting the larger lighter gravity material over the riflies.

3. In a pneumatic separator for separating coal from refuse, a primary reciprocating separating deck having a banking bar and sloping to one side for effecting a partial separation of heavy gravity refuse from'raw coal, a secondary reciprocating separating deck having a banking bar and sloping in the same direction as the primary deck, said secondary deck being adapted to receive the partially cleaned coal from the primary deck and to separate the remaining refv use from the coal, riffles on said decks arranged at an angle to the direction of reciprocation, each of said decks being provided'with a' multiplicity of air jet apertures, means to supply airto I said apertures, a passageway for refuse at the upper side of said secondary deck, means for dividing the partially cleaned coal from the" takes the finer refuse" coming. from the upper side of the riflies, and conveys'this refuse to the member 54 which carries the refuse forward below the deck level to the point of refuse discharge. A gate plate 55 provides an opening over which the larger refuse passes, and then moves forwardly along the deck. Bolts 55 in slots 51 will regulate the width of the opening. Openings 58 may be left in the rifiles so that more fine refuse will work down to the passageway 53. Near the end of the banking bar 'I there is a gate 59 held in adjusted position by bolts ISIS in slots 6|, and gate Illa is attached to pivot bolt 62,-and held in the clamped position by the nut 63. Pipe opening 64 provides an outlet for very fine material which passes through the openings 5a when the table is stopped, or air pressure is' low, and then moves along the bottom of the air chest. A deflector 65 is used to direct material from the lower side of the deck to the opening 64.

The general operation of the primary deck A and the secondary deck B in Figure l is the same as described in my copending application, Serial No. 38,105, except for the substitution of the chutes I1 and I'Ia, and the rifiles 60 for the coal supporting bars. The chute I I is fixed above the cleaning surface on section 13, while the chute Ila is bolted to the other members so it may be moved to adjust the amount of material which goes direct from section A to section B for retreatment under reduced air currents and a different deck motion. The coarser material which goes to chutes I1 and Na is carried by chute I'I above the deck surface below, where the finer material is being re-treated or the finer refuse is moving forwardly to the front end of the deck. The bed of smaller material on the deck will thin out under plate I! and permit the discharge of the larger material on the cleaning area for retreatment, or the larger material may be carried across the lower deck direct to the product hoppers. The chute IT has perforations I'Ic to assist the air in its escape so that it does not blow sideways underneath and interfere with stratification. For the same reason it is well to keep the plate II as high as possible above the deck, and an inclined section III) will help to give a better discharge to the deck below. The riflies 6b are made very low as there will be no large material on this part of the deck. The rifiles 60 have an upper edge turned downward to assist the air and vibratory deck in carrying the bed of coal with its larger particles above the deck surface using a minimum of air. Slots 43 are provided for the escape of coal which may get under the projection and be raised by the lifting currents of air, while the small refuse continues to the ends of the rifiies. Another form of rifiles Ed is alsoused to reduce the air necessary to maintain a bed of coal over the deck, or above a section of deck, the bed containing a considerable size range from which the larger refuse has already been removed. The reduced air currents permit a more eilicient separation of the smaller particles according to specific gravity. One or both of these forms of riffles'may be used instead of carrying the larger sizes on the plate II. They may be used also on a part of a single deck.

The refuse is trapped by riflles and guided. forward by them with the deck action. As the path is somewhat inclined there is a slight tendency for slate to slip backwards. To move the refuse forward more quickly steps 45 may be attached tothebottom of the rifiles along their upper side,

ment" to' the refuse. Rivets 44 with their for ward edge clipped ma be inserted in the deck bottom for the same purpose. In moving forward slatemay pass over the rivet heads, but after it is over the clipped edge offers a stop so that the slate can not move back readily. Either one of these means or both of them together may be used to obtain a quicker movement of the refuse.

The preliminary treatment of coal as it passes from the feeder to the deck is covered by my Patent No. 2,022,588, but an improved arrangement is shown in Figure 4. A similar arrangement is shown in Figures 5 and 6, except that the air'behind the feed stream which has passed upwardly through the holes 5a in the deck is practically surrounded-by the parts" 4, 5, 33, 35 and the feed stream, so that it must pass forwardly through the feed stream which flows between the members 35.

Between the concentrator plate 9 and the wedge shaped bar 2'! there is a space through which the air-rises from the air chest to pass along the upper side of the'plate 9 against which the refuse 34'is banked. The forward motion of the deck, causing the refuse to bank against the banking bar concentrator plate 9, together with the wedge shaped bar 27 and the inwardly curved and upwardly inclined concentrator plate, with direct currents of air along its lower side, cause the refuse stream to move upwardly and then along the curve rearwardly towards the deck, and to rise to its greatest height along the under side of the concentrator plate. With suificient refuse the upper part of the refuse stream along the concentrator plate will continue to'drop off and move backward and downward towards the deck. This will give the stream of refuse a slowly rotating motion as it moves forwardly alongthe banking bar. The concentrator plate may be set lower at itsdischarge end and give the refuse stream a constantly changing cross section. These various means will bring different parts of the refuse stream to the surface as it moves ahead and give any coal trapped with the refuse a chance to escape and move downwardly back to the deck, and also tend to regulate and make the refuse stream move more uniformly. The latter is quite important as a change in the refuse stream calls for an adjustment of the gates to divide refuse, middlings, and clean coal. When refuse is directed back from the banking bar towards the deck it will sink to the bottom and be again brought back to the banking bar. This helps to keep a good refuse line along the banking bar, which will tend to crowd out and hold the lighter material back andgive a more uniform discharge of refuse.

In a separator of this type the larger coal works forwardly. To get it over the rifiles the air may be increased and the height of rifiles reduced as shown in Figure 4. This is common practice but some of the larger coal still passes to the end ofthe riflles with the refuse. To further correct this difficulty the rear pair of toggles is set more nearly vertical than the forward pair, which gives a greater vertical motion for the forward part of the deck. This is to help the air to lift the coal over the riflies. In addition to this a lateral and forwardly inclined deflector 36 is placed across a series of riflles to help make a more complete separation. It may be adjusted vertically soonly a certain size or a given quantity may pass underneath. The lower end is set back so it will slightly bank and deflect the upper separatron orthe heavy gravity material-from the gift-gravity; material, low'er'reci-procable sepating' deck having a bankingT-bar and sloping in aine direction as the' upper deck," said.- lower leane material from the upper deck, 'i-an'd: to

parate add-itionalheavy gravitymaterlal from the lig ht gravity; material, -rifles on-isaid decks arran edat=an angle to thedire'ction of reciprocation; each of said decks-being supplied with a multiplicityof' air jet aper'tur'es, means -to supply air to said apertures, means tO-re'ciprOcate the 1 decks, a passageway for: the heavy gravity material atthe upper side ofthe': -'lower 'deck,a discharge chutej extending from the lower side of "the upperdeok andover said passagewayon the lowerdeck, a plate-over 1 and "above the'cleaning area of the lower deck 'to" c'arry' the coarser partiallycleaned material fromthefprimarydeck to '-a point'on the 'se'condary deck where itcan' be re treated'without interfering with the re-treatment of the smaller partially cleaned-material from-the primary-deck, the heavy gravity material passing along the upper sides of both decks and the banking bars to discharge at the extreme end of the lower separator, while the lighter gravity material is discharged along the lower side of the lower separator.

5. In a separator for removing refuse from coal, a primary inclined reciprocable deck for effecting a preliminary separation of heavier refuse from coal, at secondary inclined separating deck receiving a stream of partially cleaned coal from the primary deck and separating additional refuse therefrom, said secondary deck being provided with a passageway for refuse adjacent its upper side, means for making a division between the coarser and finer treated coal from the primary section and to carry the coarser material over and above a section of the lower separating deck used for the re-treatment of the finer treated coal from the primary deck, rifles on said decks arranged at an angle to the direction of reciprocation, each of said decks being pervious, means to supply and control the fiow of air through said decks to provide a relatively large quantity of air to the primary deck and a relatively small quantity of air to the secondary decks, means to.

reciprocate said decks, and means for remixing the coarser treated coal and the remaining finer treated coal on the lower forward part of the secondary deck for further re-treatment.

6. A dry separating apparatus having a laterally inclined pervious reciprocating deck provided with diagonal rifles, said deck having a section depressed to form a valley below and across a series-of rifles, o permit small refuse to leave and travel underneath said rifles, said valley providing for the movement pf small refuse forward and downward along the deck bottom at an angle to the direction of the rifles, said rifles directing the coarser refuse forward and upward.

'7. A dry separating apparatus having a laterally inclined pervious reciprocating deck provided with rifles and means to supply air through the deck, said deck having a valley crossing underneath a series of rifles, the section of ,said deck approaching said valley being provided with relatively weak currents of air passing upwardly from below, and the section of deck ahead of said valley having stronger upward currents of air, along the bottom of said valley a gate to regulate the size and quantity of material leaving the sides of the rifles to be conveyed laterally deck, and-'then forwardly "to'the' point where the main 'refusestreamis discharged; I

plate inclined" downward towards the low er'side of the" deck, and laterally upward towards the allowrefuse and-a-limited amountofcoal to pass underneath; and -slightly bank the stratum of forward part of the deck,--and set above and ac ross a seriesor'rimes, said plate being spaced to coal above, the double'slop'e of said plate assisting the air and the-motion of' the deck to' lift and '15 c'onvey -tlie coalover the'ri-fles more rapidly to thelowersideo'f thedeck, and-save'large coal from being dis'charged with the refuse;

- 9. The method of separating raw materials of Y diiferent specific'gravitiesand size, such as raw coal, comprising'feeding the material in a thin freely flowing stream upon an-inclined'reciproeating support; conveying, spreading, and stratifying the materialupon the support by a reciproeating rocking motion, and currents of air directed through the'support, causing the refuse to move along guides diagonally upward and forward, and the lighter gravity material to move forward and downward becoming gradually coarser towards the forward part of the bed, reducing the air pressure under a portion of the support carrying the finer material for re-treatment, moving the resulting refuse along guides carrying coarser refuse, and then removing the finer refuse from the guides and causing it to move at an angle from the coarser refuse, and causing the finer refuse to move forward and downward along the reciprocating support to a point of discharge, to avoid remixing the finer refuse with the coal where the coal is coarser andthe air pressure is greater.

' 10. In a separator for separating refuse from coal, a pervious inclined reciprocable deck with rifles, and means to force air upward through said deck, said rifles rising from the deck but having tops inclined downward towards the deck and the flow of coal, said tops being inclined to assist the air in lifting the larger lighter gravity below the rifles towards the lower side of the material over the rifles, and slots in the tops of saidrifles for the escape of small coal.

11. A dry separating apparatus having a later-' ally inclined pervious reciprocating deck provided with rifles, said deck having a series of rifles with a line of openings for the lateral escape of small refuse from the upper sides of said series of rifles, and below and ahead of said openings a passageway disposed transversely to the rifles and depressed to form a valley in the deck/said passageway to collect the small refuse and convey it laterally below and across a second series of rifles, together with small refuse from said second series of rifles, to the lower side of said deck.

12. A dry separating apparatus having a laterally inclined pervious reciprocating deck provided with diagonal rifles, said deck having a section depressed to form a valley at an angle to the rifles, said valley providing an opening between the deck and the rifles for the escape of small refuse to move along the bottom of the deck towards the lower side of the deck, while the coarser refuse follows the rifles towards the upper side of the deck.

13. A dry separating apparatus having a laterally inclined pervious reciprocating deck provided with diagonal rifles, said deck having a section 14. A dry separating apparatus having a later-;

ally inclined pervious reciprocating deck provided with diagonal riflles and means to supply air through the deck, said deck having a line of openings spaced to be just above the riflles, the section of the deck approaching said line of openings being provided with relatively weak currents of air passing upward from below, and the section of the deck ahead of said line of openings to have stronger upward currents of air, and

underneath said line of openings a passageway a disposed transversely to the rifiles, said passageway to remove the smaller size refuse from the riflles and convey it laterally below the riffles to the lower side of the deck, and then forwardly to unite with the main refuse stream. H

f 15. The method'of separating raw materials of different specificrgravities and size, such as raw coal, comprising feeding the material in a thin freely flowing stream upon an inclined reciprocating support, conveying, spreading, and stratifying the material upon the support by a reciprocating rocking motion, and currents of air directed through the support, causing the refuse to move along guides diagonally upward and forward,,and the lighter gravity materialto move forward 7 and downward becoming gradually coarser towards the forward part of the bed, reducing the air pressure under a portion of the support carrying the finer material for re-treatment, moving the resulting refuse upward and forward along a series of guides carrying coarser refuse, and then removing the finer refuse from the guides and causing it to move downward and forward along the reciprocating support, so as to avoid remixing the finer refuse with the coal where the coal iscoarser and the air pressure is greater.

JAMES H. DICKERSON.

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