US 2014249 A
Description (OCR text may contain errors)
Sept. 10, 1935. J. H. FLETCHER 2,014,249
METHOD AND APPARATUS FOR SEPAHATING REFUSE FROM COAL Original Filed Nov. 21, 1930 2 Sheets- Sheet 1 Sept. 10, 1935- J. H. FLETCHER 2,014,249
METHOD AND APPARATUS FOR SEPARAT iNG REFUSE FROM GOAL I Original Filed Nov. 21, 1930 2 Sheets-Sheet 2 Invenfi; limes fi/Eier Patented Sept. 10, 1935 UNITED sr 'res METHOD AND APPARATUS FOR SEPARAT- ING REFUSE FROM COAL 'James H. Fletcher, Wilmette,-lll., assignor, by mesne assignments, to Peale-Davis Company, Wilmington, Del., a corporation of Delaware Application 2 Claims.
which combines the use of mechanical means and air under pressure for effecting the separation.
Briefly described, an apparatus is used comprising an upper deck on which the material tov be separated is deposited, and a.lower deck for receiving the refuse, the space between the decks being confined so that a superatmospheric air pressure may be maintained between the decks. Means is provided for reciprocating or moving the table so that the material on the upper deck will be agitated and urged along the table from the receiving to the discharge end thereof. The upper deck is perforated or provided with a plurality of openings of a determined size, and the air pressure between the decks is maintained just sufliciently high so that the air jets flowing upwardly through the openings or perforations will be just sufficient to support coal particles of a size capable of passing through these openings, but
insuflicient to support the heavier refuse particles 3 of similar size. Suitable means is provided for Y discharging the refuse from the lower'deck without excessive loss of air pressure from the space between the decks.
' The principal object of this invention is to provide an improved method and apparatus for separating refuse from coal or similar material,
such as briefly described hereinabove and dis,- closed more in detail in the specifications which follow.
Another object is to provide an improved apparatus for air-cleaning coal or similar material.
Another object is to provide an improvedapparatus comprising a series of similar separati g tables, each adapted to separate out refuse particles of a substantially predetermined size.
Another object is to provide an improved air separatioirtable adapted to successively but sepa- .rately withdraw refuse particles of substantially predetermined sizes from the mass of mixed moi terials. Other objects and advantages of this invention will be more apparent from the following detailed description of certain approved form of apparatus adapted to carry out the improved process herein disclosed.
In the accompanying drawings: Fig. 1 is a longitudinal vertical'sect'ion through a .simple form of the apparatus.
Fig. 2 is a plan view, partially broken away, of the apparatus shown in Fig. 1.v v
November 21, 1930, Serial No. 497,142 Renewed January 24, 1935 p Fig. 3 is a horizontal section of the apparatus taken substantially on the line 3-3 of Fig. 1.
Fig. 4 is an enlarged vertical section through a fragment of the'separating table illustrating the separating process.
Fig. 5 is a diagrammatic side elevation illustrating a series or battery of separators of the type shown in Fig. 1.
Fig. 6 is a partial verticalsection through a separating table embodying a plurality of sepa- 10 rating zones, each adapted to divide out a difierent size of refuse particles.
Referring first to the simplified example of the apparatus as illustrated in Figs. 1, 2 and 3, the separating table indicated as an entirety at A is 15 suspended by a plurality af links I which are pivoted at their lower ends 2 to the table, and which are pivotally supported at their upper ends 3 j from brackets 4 carried by an overhead supporting structure 5. A pitman 6 pivoted to one end 20 of table A at I, has a collar 8 at its other end surrounding an eccentric 9 keyed on shaft III, which is rotated in any suitable manner. It will beapparent that as the shaft I0 is rotated the eccentric will cause pitman 6 to reciprocate the table A and simultaneously give a small up and down movement to the table, due to the oscillation of the supporting links I.
The table A comprises an upper deck II and alower deck l2 which are spaced apart to provide 30 an intervening chamber. l3 which is .closed on three sides by the vertical walls It, and which is closed at the discharge end by a movable gate II.
A fan or other suitable air pumping mechanism l8 discharges air under pressure through conduit 35 ll provided with pressure-regulating valve ll' into a chamber l8 having flexible side walls- IS, the upper side of chamber" being closed by 'the lower deck I? of the table A. This lower deck is formed with a multiplicity of small perforations 20 whereby the air under pressure will be discharged from chamber it through lower deck I! into. the chamber l3 between the upper and lower decks of the separating table. The upper deck II is formed with a plurality of holes or perforations 2|, thesi'ze or diameter of which is determined by the size of. the refuse particles or lumps that are to be discharged therethrough' by gravity. The air pressure built up in chamber I! by fan It will be regulated in accordance with the size of the openings II in the upper'deck so that the force of the air jets passing upwardly through openings 2| will be justsufllcient to support particles of lumps of coal capable of passing through 65.
indicated at :c.
the openings, but of insufiicient force to support the heavier refuse particles of similar size.
The broken m'ass consisting of mixed coal and refuse is discharged onto upper deck I I from a chute 22 and is confined on this deck by the upright walls 23 surrounding three sides of the table. A chute 24 at the delivery end of the table serves to discharge the cleaned coal from the table onto a conveyor 25 or any other suitable receiving means. A chute 26 projects from the lower deck'IZ of the table for discharging refuse from the lower deck onto a conveyor 21 or into any other suitable receiving means. This chute 26 is I provided with a discharge gate 28 in addition to the gate I5, already mentioned. The purpose of the two gates I5 and 28 is to permit the discharge of solid material'from the lower deck I2' without an excessive loss of air pressure in the space between the decks. The gate 28 will be closed and' the gate I5 opened until a sufllcient quantity of refuse has collected in the chute 26, then the gate I5 will be closed and the gate 28 opened to discharge this refuse onto the conveyor ZI. Any other suitable forms of gates or valves could be used for this purpose, the mechanism hereinabove described being merely a diagrammatic example of apparatus suitable for this purpose.
Referring now more particularly to Fig. 4, the principle of operation of this improved apparatus and separating process will be more definitely described. The separating table will be reciprocated so that the mass of mixed material supported onthe upper deck II will be continually agitated and urged 'alongthe table in one direction, for example, in the-direction of the arrow Air under pressure is forced through the openings 20 in the lower deck I2 in sufiicient quantities to build up a super-atmospheric pressure in the chamber I3 between the two decks so that air jets will be directed upwardly through the several openings 2| in the upper table II, all as indicated by the small arrows in the drawings. In thisflgure the lumps or particles of-refuse are heavily shaded, whereas the particles of coal are indicated by lighter shading. The force of these air jets will be just sufficient to support lumps or particles of coal, such as indicated at b, which-are small enough to pass through one of the openings 2|. However, this air pressure is not sufllcient to support par- I ticles of refuse of similar size, as indicated at a,
and these pieces of refuse will drop through the openings 2I against the force of the air streams and be caught by the lower deck I2. It is desirable that the openings 20 in the lower deck may be made as small as practicable so as to prevent the passage of refuse material therethrough,
but these openings should be in sumcient numbers to permit-a free flow of air upwardly through the lower deck so as to keep up the air pressure within the chamber I3. It will be apparent that larger lumps of coal, such as indicated at 0, would not be supported by the air pressure, but these pieces are too large to pass through the openings 2I and will be mechanically supported uponthe upper deck II. Also smaller sizes of coal, such as indicated at d, will either be supported by the air pressure over the openings 2I or will be supported mechanically upon the upper deck I I, according to their-position on the table. As a result, all of the coal will .be maintained upon or above the upper deck II, whereas refuse of a predetermined size will be permitted to pass through the openings in the upper deck under the influence of gravity and'will be upon the above the upper deck, butit is contemplated that these smaller sizes will be subsequently removed 5 by means of additional separating tables in which smaller openings are provided in the upper deck and the air pressure is decreased.
One example of an apparatus embodying a series or battery of these separating tables is illustrated diagrammatically in Fig. 5. Each of the units A, B and C may be of the type hereinabove described. The coal from the first separating table A, from which the larger particles of refuse have been removed, and discharged onto the conveyor 29, is discharged from theupper deck onto the upper deck of the second separating table B. In this second table, the openings 2! in the upper deck are reduced in size and a decreased air pressure is used, whereby refuse particles of a smaller 20 size are permitted'to gravitate out of the mass and are discharged from this second table onto the conveyor 30. The coal from the second table B is discharged onto the third table C'where a smaller size of refuse is separated out, and so on throughout the series.
Another form of the invention is indicated in Fig. 6 of the drawings. In this form a single long separating table is'used, the space between the upper and lower decks being separated by a plurality of transverse vertical partitions 3| into a series of separate zones, such as indicated at 32, 33. 24 and 35, respectively. The openings in the upper deck II are made successively smaller in the several zones throughout the series. For 85 example, in the zones as shown in Fig. 6, the opening's 3B .in the first zone 32 will be larger than the openings 31 in the second zone 33, and the openings 38 in the third zone 34 will be smaller than the openings 31 in the second zone. The 40 I air pressures maintained in each of the separate zones will be correspondingly decreased, whereby refuse particles of successively decreasing size will be withdrawn from the mass as it is urged along the table in the direction of the arrow, indicated at x- The refuse deposited on the lower deck I2 in each zone will be removed through traps or valves 39, as hereinabove described, and the cleaned coal will be discharged from the delivery end of the table at the end of the series 5 of zones.
While the expedient of providing the lower deck I2 with a multiplicity of small openings is desirable for maintaining a substantially uniform air pressure throughout the horizontal area of the table, or separating zone, the air could be forced into the chamber I! through one or more conduits communicating with either the bottom or sides of the chamber so as to maintain the desired air pressure between the upper and lower decks. In such case, an imperforate, or a substantially imperforated lower deck I2 could be emciency of this improved method of separation depends upon a certain definite ratio being maintained between three factors, first, the number 7 and size of the openings in the upper deck, second,
the open area of the lower deck (which should have a multiplicity of very small holes), and third, the static'airpressure maintained between he decks.
with these three factors properly balanced for the size of the refuse that is to be removed, any small size of the refuse, or other similar material. can be separated out by this process. It will be noted that this process could be used for selecting out particles of a desired size of any relatively heavier material, from a mixed mass containing this material.
It is to be understood that the simplified forms of apparatusherein disclosed are shown and described merely by way of example and that many other designs of apparatus could be adapted for performing this improved separation process, all of which are intended to come within the terms of the claims which follow.
1. A process of purifying coal which comprises maintaining a bed of raw coal having a substantial variance in size of the pieces and particles, progressing said bed across a plurality oi pervious zones having successivelysmaller apertures therein, passing air currents upwardly through the traveling bed and regulating said air currents so as to subject the zones with smaller apertures to lesser intensity of air action and by said air regulation causing larger particles of refuse to fall through the coarsest apertures while floating the lighter material and the flner'v refuse particles by air pressure and thereafter causing said finer refuse particles to fall through the smaller apertures against the lesser air force while maintaining the lighter material above said apertures.
2. A process of purifying coal which comprises maintaining a bed of substantially continuous raw coal having a substantial variance in size of the pieces and particles, progressing said bed across a plurality of pervious zones having successively smaller apertures therein, passing air currents upwardly through substantially all parts of the traveling bed and regulating said air currents so as to subject the zones with smaller apertures to lesser intensity of air action and by said air regulation causing larger particles of refuse to fall through the coarsest apertures while floating the lighter material and the finer refuse particles 29 by air pressure and thereafter causing said liner refuse particles to fall through the smaller apertures against the lesser air force while main taining the lighter material above said apertures.
JAMES H. FLETCHER.