US2012633A - Apparatus for the pneumatic separation of materials comprising elements of different specific weights, such as raw coal - Google Patents

Description

Aug. 27, 1935. F. J. MEUNIER F 2,012,633

-APPARATUS FOR THE PNEUMATIC SEPARATION OF MATERIALS COMPRISING ELEMENTS OF DIFFERENT SPECIFIC WEIGHTS, SUCH ,AS RAW COAL Filed Nov. 22, 19252k 3 Sheets-Sheet l F. J. Meunier* F. J. 'MEUNIER Aug. 27, 1935.

APPARATUS FOR THE'PNEUMATIC SEPARATION OF MATERIALS COMPRISING ELEMENTS OF DIFFERENT SPECIFIC WEIGHTS, YSUCH AS RAW COAL Filed Nov. 22, 1932 3 Sheets-Sheet 2 Aug. 27, 1935. F, J MEUNlER 2,012,633

APPARATUS -FoR THE PNEUMATIC SEPARATION OF MATERIALS GOMPRISING ELEMENTS 0F DIFFERENT SPECIFIC WEIGHTS, SUCH AS RAW COAL l iFiled. Nov. 22, 1932 3 Shee'os--SheeiI 3 Patented Aug. 27, 1935 'UNITED STATES APPARATUS FOR THE PNEUMATIC 0F MATERIALS COMPRISING ARATION SEP- ELEMENTS 0F DIFFERENT SPECIFIC WEIGHTS, SUCH AS RAW COAL Flicien Joseph Meunier, Neuilly-Sur-Seine,

' France Application November 22, 1932, Serial No..643,926 In France December 2, 1931 2 Claims. (Cl. 209-466) This invention has for its object improvements in apparatuses for the pneumatic separation of materials comprising elements of different speciiic weights, such as raw coal. The invention relates chiefly to apparatuses of this class which comprise one or more sloping surfaces or tables over which the material to be separated is caused to travel and which are provided with apertures through which air under pressure is forced up- Wardly to stratify the bed of material.

The primary object of my invention is to improve the efficiency of the apparatuses of the general type above set forth, i. e. to increase the weight of material per unit of area of the perforated table which can be treated in a given lapse of time, thus reducing the length and bulk of the apparatus as compared with the heretofore known apparatuses of the same class. Another object is to improve the dry separation process by pneumatic way so as to provide for a. proper adjustment, at each point of the bed of material of the air draft with respect to the state of the bed at this point and for this purpose to provide for a separate and accurate control of the air draft at various points of the bed of material so as to suit every working condition which may occur in practice. A further object is t-o design an apparatus for carrying out such an improved process and more particularly to devise means wherebyl the air draft through the bed of material will be divided in a plurality of separate air streams, the pressure of each of which is separately adjustable at will. A still further object of my invention is to provide improved means for separating minerals of different specic gravities, after they have been arranged in layers upon the perforated table, without disturbing the general state of stratification of the material bed.

With these and other objects in view as will appear hereinafter, my invention resides in the novel combination of steps and in the novel arrangement of parts and provision of means as will be set forth hereinafter and more fully pointed out in the claims.

Various embodiments of my invention are illustrated by way of example only in the annexed drawings in which:

Fig. 1 is a vertical longitudinal cross-section through an embodiment of the invention.

Fig. 2 is a .corresponding plan view.

Figs. 3 and 4 are transversal cross-sections taken along lines 3-3 and 4 4 of Fig. 1.

Fig. 5 is a detail longitudinal cross-sectional view according to line 5-*5 of Fig. 2 and at a larger scale, of the schist removal device.

Fig, 6 is a corresponding sectional view taken along line 6 6 on Fig.q2 of the pure coal removal device.

Fig. 7 is a part plan view of a modified em bodiment and Fig. 8 is avertical longitudinal section of another and still further improved embodiment.

The apparatus illustrated comprises in a known manner a table I the bottom I2 of which is provided with apertures distributed over its whole or substantially its whole area, means for forcing air upwardly through said table I, and means for causing the bed of material formed onto said table to travel along thelatter. In the various embodiments illustrated said latter means consistin a slight longitudinal slope given to the table and in a mechanism adapted to impart a reciprocating rectilinear 4motion to the table as for instance an eccentric 9 keyed on a driving shaft and connected through the eccentric rod l to the table I with interposition of buffers 8; the

eccentricity is preferably adjustable, whereby al.-

lowing to vary the stroke of the perforated table. The means for forcing air through the table I consist preferably of a fan 5 the outlet of which is connected to a stationary and air-tight casing 4 provided beneath the table I and over its whole length. Said casing 4 serves as a support for the table I .which rests thereon through the medium of ball bearings 2 provided with dampers 3. The ball bearings are preferably adjustable in height whereby-the slope of the table can be varied. Flexible joints 6 connect the lower edge of the shaking-table with the upper edge of the aircasing so as to allow the reciprocating motion of the table over the air-casing while ensuring a hermetically air-tight connection between these two parts.

The apparatus further comprises means Whereby at least a part of the undermost layer of the bed of material can be removed at predetermined points of the path of the latter. In the embodiments shown in Figs. l, 2 and 8 the apparatus is provided for this purpose with two suchremoval sections I3 extending Iacross the whole width of the table which is thu'sfgdivided into three concentrating sections II bt it could obviously be provided with less or more removal sections.

The bottom ofthe table in these transverse re-l moval sections I3 is made of solid iron-sheet and is preferably more inclined than the apertured bottom of the concentrating sections. Said solid iron sheet is apertured in a convenient manner to enable the heavier pieces which constitute the undermost layer of the bed to fall through the table into channel means I4 provided below and a proper device enables to control this outflow of the heavier particles. The arrangement is preferably`as follows (Fig. Each solid iron sheet I3 is provided with a continuous transverse slot under and along which extends a shutter 22 manually adjustable by rotationv about its axis having a part in the shape of a cylindrical surface coaxial with the pivoting axis and adapted to engage both edges of the slot; thus, by rotating the shaft 22 I will vary the width of the slot and hence the discharge of the heavier pieces of the material subjected to treatment without disturbing the state of stratification of the bed since the deflection of the Apath of the latter around the shutter is quite progressive.

In order to provide for a more accurate separation of the heavier particles from the bed I prefer to provide the perforated table on at least part of the length of each concentrating sections or of some of them, and adjacent the following removal section, with a plurality of longitudinal channels, open at their upper part and tapering in the direction-of ,travel of the material, the height of said channels being less than the thickness of the material bed. In both embodiments illustrated said channels are defined by small angle bars 20 securedonto the perforated bottom I2 of the table in the-second half of each concentrating section. In the present instance there are in each section three sets of two such bars 20 each, each set forminga kind of wedge and the apex of the three wedges being situated ,on a common line perpendicular to the longitudinal axis of the table. Theangle bars 20 project from the bottom.l2 of a quantity far less than the height of the table sides, in such a manner as not 'to substantially project above the layer comprising the heavier particles already stratified. In this case the discharge of the latter takes place through a plurality of discharge openings provided in the bottom of the table and in length- Wise register with said channels. However I still prefer to use as shutter 22 a rotatable shaft having a single recess of a length substantially equal to the width of the table and to divide the slot in the table by prong like extensions of the table bottom into as many separate openings as there are channels for the heavier particles.

My improved apparatus is further provided with means for the removal of the uppermost layer of the material bed at intermediate points of the length of the table. Such means is preferably located in the vicinity of the removal means for the undermost layer and consists for instance in a scraper 25 which can be adjusted at will to vary the thickness `of the removed layer; this can be obtained in a. proper manner by pivotally mounting the scraper 25 and operatively connecting it to a controldevice including a screw and nut contrivance and a handle wheel 26 as illustrated in Fig. 6. In the embodiment illustrated the scraping means 25 does not extend over the whole table width but is' subdivided in a plurality of separate and separately adjustable Scrapers 25 located substantially in the same transverse removal section I3 as the removing means for the undermost layer but only in lengthwise register with these parts of the table which are comprised between the sides of each of the aforesaid deflecting wedges. With such an arrangement the thickness of the material bed on the table progressively decreases from one section of the table Ato the next one as weli as the differences between the specific weights of the various particles in the bed since the heavier and the lighter one are removed at various points of the table. As the thickness of the bed might become too small on the end concentrating section I prefer to give to this section a progressively decreasing width and with a view to enable the apparatus to be used for the treatment of materials having a small or large percentage of tailings I prefer also to provide my apparatus with means whereby the useful width of the end concentrating section and hence the thickness of the bed can be adjusted at will. To this end I provide the end section with two side angle bars 32 adapted to be swung apart or towards each other overthe bottom of the table by means of a control device including a handle wheel 34 adapted to turn a screw 33 with two opposite pitches respectively in mesh with nuts secured to the side angle bars 32.

The discharge means at the end of the table includes a shutter or shaft 21 similar tothe shutters 22 above described and a second similar shutter 28 located beyond the shaft 21, whereby the material can be classified in three different categories, the shafts 21 and 28 serving respectively to control the discharge ofthe undermost and intermediate layers which fall into channels 29 and 30 while the uppermost layer which proceeds onover the shutter 28 is removed through the channel 3|.

In the modified embodimentlillustrated in Fig. 7, I use a kind of wedge 36 axially movable and slidable on the table to adjust the width of the end concentrating section and I move said wedge by means of a control contrivance including a screw and a handle wheel.31.

It is to be noted thatby adjusting either the angle bars 32 or the wedge 36 I vary the length of the discharge openings controlled by the shutters 21 and 28. 1

The operation of my improved apparatus is as follows:

The raw material, previously sifted into different categories which` have been stored separately in hoppers 35 feeding different apparatuses is distributed evenly by a feeding device 36 ontol the shaking table the first section I D of which acts as a sieve and serves for removing through a channel 31, the non-classified material resulting from the imperfect preliminary sifting together with all the dust due to the breaking up of the material during its handling and storing.

The non-classified material and the dust are returned to the flrst sifting apparatuses and when they pass out of these they take againv their place in the corresponding categories.

In case of fine moist coal, an inlet 38 of forced air allows the cleaning of the sheet iron perforated with small holes; in this case, the feed is held up an instant through controlof a damper 39.

The material travels then along the table as usual in the apparatuses of this class and arrives on the first concentrating section II; the air draft through the table in said section being properly adjusted a rst pneumatic stratification takes place in the first part of this first concentrating section. On arriving adjacent the defleeting surfaces 20, the undermost layer enters channels ows through a bed portion of less thickber ma, 40h, 40C forms a second expanding chamness and deprived from its undermost layer so that it acts now on mixed material and pure coal only. The separation is thus furthered in those regions and the-uppermost layer removed by the scrapers 25- contains coal particles in a quite pure state. The material proceeds yet onto the next concentrating table section where the same process takes place again.

As the thickness of the bed decreases progressively from one section to the next one, as well as the differences between the specific weights of the various particles, it is a primary matter that the air pressure acting in each concentrating section can be accurately adjusted.

f yFurther it is known that the air-pressure must become greater as the heavier particles are settling on the bottom of the table. It is hence highly desirable to have means whereby the air pressure can be adjusted to suit these various working conditions and, moreover during the working of the apparatus'as the aforesaid working conditions are not permanent ones but vary continuously with the state of the material, in particular with its higher or lower grade of purity. My improved process of pneumatic separation contemplates therefore to use various air pressures in the various sections of the bed where concentration is proceededjwith, said pressures decreasing from one section to the other in accordance with the direction of travel of the bed. and also various pressures in one and the same section, said pressures increasing in the aforesaid direction. yThese pressures are preferably so graduated that the minimal pressure in a section is less than the minimal pressure in the preceding section and .greater than the minimal pressure in the following section. Still further my process contemplates varying at will and independently the pressures in each section and preferably also the pressure in each' sub-section independently of the pressure in the other subsections. v

To carry out the aforesaid improved process I provide the table on its under side with a plurality of transverse partitions I1 dividing each concentrating section in subsections and connected to corresponding partitions carried by the casing 4 by means of exible joints I8, thereby defining a plurality of air boxes I6 each of which is provided with throttling means I9 consisting, in the embodiment illustrated, in two superposed perforated iron sheets, one of which is stationary and the other movable (Fig. 4).

These various shutters I9 enable to vary at will the quantity of air which enters each air box I6 defined by two adjacent partitions II the corresponding shutter I9 and the bottom of the corresponding sub-section of the table; each box I6 forms thus a kind of air expanding chamber where the air pressure can be adjusted separately and independently; the various air boxes I6 of one and the same concentrating section are preferably fed from a common air chamber 40a, 0b. 40e, the inlet of each of which is provided also with its own throttling means Ma, IIIb, 4Ic.

It is preferred to branch in parallel the three chambers 40a, 4Gb, 40C on the same air supply pipe 42 connected to a fan (not shown). Obviously each air chamber 40a, 40h, 40e could be fed by a separate air supply pipe or fan. Y

In the embodiment just described each chamber. It will thus be readily understood that it is possible to adjust independently the pressure pre- 'vailing in eacli'of said chambers 40a, 40h, 40e common to the various air boxes I6 `of one and the same concentrating section of the table and, moreover, thepressure prevailing in each of said air boxes.

This adjustment is preferably attended to in such a manner that the pressure in the air chambers'40b, is'less than in the chamber 40a but greater than in the chamber 40o, while the pressures in the various air boxes of each concentrating section increase in accordance with the direction of travel of the material.

I consider convenient to provide sub-partitions 43 in each air box I6 with a view to thoroughly guide the flo-w air and avoid eddies.

Owing to such an arrangement the air pressure at each point of the material 'bed can be accurately adjusted to suit the state of the bed at this point and this results in a marked increase lof the output of the apparatus per unit of table surface.

What I claim is:

l. In la pneumatic separator for raw material such as raw coal and the like of the type comprising a shaking table, a shaking table of substantially the same width on at least the major part of its length and provided locally with a plurality of channels distributed on its whole width, open at their upper part and extending and tapering substantially lengthwise of the table, the height of said channels being less than the thickness of the material bed, the table being further provided aft said channels with a plurality'of transversely aligned slots each of which is in lengthwise register with a corresponding channel, longitudinal prong like portions of the table separating two consecutive slots, and means for simultaneously controlling the width of all said slots, said means including a rotatably supported cylindrical shaft located underneath said slots and extended upon the whole width of the table in register with the slots, further so arranged that its lateral surface will engage simultaneouslyboth transverse edges ofall the slots and provided with a cut out portion of a length substantially equal to the total length of the transverse slots.

2. In a pneumatic separator for raw material, such as raw coal and the like, of the type comprising at least one shaking table, a shaking table provided locally lwith a plurality of channels distributed on its whole width, open at their upper part, and extending and tapering substantially lengthwise of the table, the height of said channels being less than the thickness of the material bed, the table being further provided after said channels with a plurality of transverselyv aligned openings, each of which is in lengthwise register with a corresponding channel, at least one slot" pierced in the table, a rotatably supported cylindrical shaft, located, underneath said slot, andrextended u 'pon the whole width of the table, provided with a cut out portion, and further SO arranged as to dene said openings with one of the edges of said portion and one edge of said slot. l

FLICIEN JOSEPH MEUNIER.

sol

Images