US2147911A - Pneumatic separator - Google Patents

Description

fFebQZl, 1939.

. I PNEUMATIC SEPARATOR Filed Sept. 24, 1954 4 Sheets-Sheet 1 Feb. 21, 1939.

F. CjMENK PNEUMATIC SEPARATOR Filed Sept 24, 1934 4 Sheets-Sheet 2 frd/M/dct/I/eki Feb. 21, 1939. F c. MENK PNEUMATI C SEPARATOR Filed Sept; 24, 1934 4 Sheets-Sheet 3 Feb. 21, 1939. F. c. MENK PNEUMATIC SEPARATOR Filed Sept. 24, 1934 4 Sheets-Sheet 4 .llliiiilliliillilll fad/mam cleaned coal.

material.

Patented Feb. 21, 1939 PATENT OFFICE PNEUMATIC SEPARATOR Ferdinand C. Menk, Hunt ngton, W. Va.

. Application September 24,1934, Serial No. 745,351

9 Claims.

This invention relates to'pneumatic separators for granular and lumpy materials, such as un- All particles of larger size than dust are hereinafter called lumps. The principal object of the invention is to obtain a clean separation with a minimum of air.

Another object is to de-dust the material as it is being separated.

Another object is to separate mixtures of high and low gravity materials in such a way that the high gravitymaterial is repeatedly subjected to an airblast to separate the low gravity material from it.

Anotherobject is to effect a clean separation in a machine ofas small size as possible.

Still another object is to separate high and low gravity material-by droppingthe mixture past a series of air blasts and retarding the material to be retreated at each air blast before it enters the blast, so that it will settle through the blast by gravity rather than driving through by momentum, thereby reducing the velocity of airrequired for separation. An additional object in this connection is to'guid'e the material between air blasts in acurved path tending to'stratify it.

A further object is to maintain a stream of suitable density of -material in front of the air blasts all the way down by making the material converge toward the center line of the air blasts as its volume is reduced by removal of the lighter A further economy of air is effected in thisway by reducing the size of the air blast ports toward the bottom of the machine, in conformance with the reduced amount of the material to be retreated. Preferably converging side walls are used to bring the diminishing quantity of material retreated toward the center line of the air blast ports, and these side walls may be made of glass to permit ready observation of the cleaning action. To avoid accumulation of material at the converging side walls; additional deflector plates may be placed inward from the side walls.

Anotherobject is'to provide a series of baflies "to return the heavier material toward the air blast ports for retreatment; these baffles preferably having flanges directed toward the air'blast ports at the top, which afford clean separation and eliminate eddy currents tending to hold the material stationary on the baffles. The baflles are to relieve-jams.

it The machine is preferably provided with final rde-dustingair blast portsacting upon the lighter eral air blast ports 4.

material after the heavier material has been separated from it.

I-have shown one machine illustrating the invention in the accompanying drawings, wherein Fig. 1 is a side elevation of the machine, with 5 portions of the near side wall removed,

' its supports,

Fig.'.8 isa fragmentary. sectional View of the upper end ofthe slide and feedinghopper,

"Fig. 9 is a section on the line 9-9 of Fig. 8, and

Fig. 10 is a perspective view of an alternative form of one of the sections of the slide.

The central feature of the machine is an inclinedslide S composed of a plurality of sections 2-. separated by air blast ports 4. This slide is inclined from top to bottom of a casing 6, which it divides intotwo .parts, an air .supply side 8 and an exhaust chamber II]. A difference in pressure on opposite sides of the slide S to cause blasts of air to blow out through the ports 4 into the exhaustchamberrl I] can be established in any desired way. I have shown a closed circuit ar- .35

rangement to illustrate the invention, but an open exhaust can be used as well. Fromthe exhaust chamber It) leads an exhaust pipe l2 connected by a down-comer I4(Fig. 1a) to a blower "IS, the exhaust side of which is connected by a conduit 18 with a pressure manifold 20. From the manifold 20 conduits 22 lead off to the sev- The air passing through air blast ports: 4 can be controlled by dampers '24 in each of the conduits'22.

The material may be fed to the upper end of the slide S through a hopper '26 (Figs. 8 and 9), at

the bottom of which is a drum 28 revolved by its shaft 30 through a pulley driven by a belt 34 '(Fig. 1) from a motor 36. The feed of material 5 onto the drum is regulated by an adjustable board -38. The material drops from the drum 28 onto the upper section 2a of the slide, down which it travels to a lip All at: the bottom of the section.

'ThlS outward flared lip reduces the velocity of .55

the material and shoots it outward in a direction approaching the direction of the first blast of air issuing from conduit 22a. The heavier material, such as the slate in coal, sinks quickly through the air blast, some of it falling directly onto the second section 21) of the slide. The lighter material, such as coal, is blown outward farther than the heavier material. At the intermediate zone is located a bafile 42a, which preferably has at the top a flange 44 extending toward the slide. The baflle is located in such a position that the flange 44 will catch the high gravity material blown farthest by the air blast, so that all of the high gravity material which does not drop inside of the baflie 420, will be caught by the baffle and returned toward the slide. The flange 44 not only tends to prevent heavier lumps striking the bafiie from bouncing over with the lighter material, but also eliminates the air currents which tend to hold the material stationary on the bafile and cause jamming. The material sliding down the section 21), as well as the material returned by bafile 42a, drops into a second air blast issuing from the conduit 22b, where the same separating action is repeated. Due to the inclined position of the slide sections 2, the material falling upon them tends to stratify, the heavier material moving in toward the slide and the lighter material being forced outward. This action is accentuated by the curved motion of the material as it moves onto the lip 40. The section 2 of the slide may consist of two plane surfaces, or it may be divided into more planes, or its surface may be a smooth curve as shown at 40 in the alternative form of slide section 2' illustrated in Fig. 10.

Below the baffle 420. there are additional baffles 42 arranged in a downwardly inclined series in front of the slide S. Any suitable means may be used for the support of these bafiles. In the drawings each bafile is supported by two arms 46 on a triangular frame composed of side bars 48 (Fig. 6) and a cross bar 50. This frame is pivotally supported at 52 on two bolts 54 extending through slots 55 in the top of the casing and held in place by nuts 56. To the lower end of the frame is connected a rod 58 provided with a handle 60. In case the material becomes jammed between the slide and baflles. the handle 60 may be pulled to swing the whole bafiie unit about the pivots 52 and then returned to position instantly when the jam has cleared itself. The nuts 56 serve to adjust the baflle unit with reference to the slide and the bolts 54 can be moved horizontally in slots 55. Thus the baffle unit can be adjusted in all directions in a plane perpendicular to the slide, which has the advantage that the air blasts can be regulated to give the proper velocity of air within the casing to keep in suspension dust of a certain grain size, and then the baffle unit can be adjusted to the correct position to separate the heavier and lighter material.

Instead of leading the exhaust from the chamber l0 directly downward from the top of the chamber, there may be provided a vertical or inclined upwardly extending dust classifying duct, such as the duct in Fig. 3, the top of this duct being connected by a downwardly extending duct 81 to the blower Hi. In other respects the device shown in Fig. 3 is similar to the one shown in the other figures and like reference characters indicate similar parts. The tall up-case 85 gives the air an opportunity to settle down to a uniform flow substantially free'from eddy-currents, which allows the dust particles larger than a certain size to settle back into the exhaust chamber In and hopper 82, so as to be removed with the clean coal. The blower l6 may be of the centrifugal dust separator type having a dust discharge pipe I'l.

As more and more of the lighter material is blown out beyond the baffles, the volume of material returned to the slide becomes less and less. If the separating chamber were of the same width all the Way down, the stream of material would become thinner and thinner, leading to irregularity of effect of the blasts upon it, and furthermore, much air would be wasted at the lower air blast ports. To maintain a suitably dense stream of material before the air blast ports, these ports are graduated in size, becoming smaller toward the bottom, so that the material is moved inward toward the center line of the ports as it descends. Along the inwardly tapering slide are two side walls 62 which keep the material on the slide and in front of the air blast ports. These side walls are preferably made of glass so that the operator can look in to see just how the separating action is proceeding. A full view of all the slide sections and baflles is provided by these side walls and the various adjustments of the baffle unit and dampers 24 make it possible to insure a correct separation at each baflle. One edge of the side walls 62 is held against the slide frame by a molding 63, while the opposite edges are held in position by plates 64 extending from the side walls 66 of the casing and provided at their inner edges with grooves 68 to receive the glass panes 62. The plates 64 guide some of the lighter material blown beyond the bafiles to the bottom of the casing and should therefore be made to withstand the wear of this material. To prevent accumulation of the material against the side walls 62, the bafiles 42 are provided with deflector blades 10 inclined downwardly toward the center line of the slide. These blades keep the material converging toward the center line as it falls. The baffles 42 are graduated in size in conformance with the shape of the slide. The graduation in size of the air blast conduits 22 is shown in Figs. 2 and 4. The three uppermost air blast ports being the full width of the casing, their conduits 22 likewise extend the full Width and are supplied from a single passage 14 formed by a partition 16 extending across the casing. The other air blast ports being of less width than the casing, their conduits 22 extend direct from the manifold 20 in the reduced width corresponding to the respective ports.

The bottom-most baflle 42m is the dividing means which finally separates the stream of material into its lighter and heavier classifications. As shown in the drawings, this baffle is of narrow width conforming to the amount of heavy impurities which would be found in a good grade of unrefined coal, but the size of this bafile, and in fact the taper of the whole separating chamber will depend upon the proportion of heavier material to lighter material. The heavier material passes out through a delivery pipe 16 normally closed by a flap valve 18. The lighter material is collected by a hopper 8D and guided to a delivery pipe 82 normally closed by a flap valve 84.

A final de-dusting blast may be arranged to blow the dust from the lighter material after the last stage of separation. In the drawings I have shown for this purpose two air blast ports 85 fed by air ducts 88 from the manifold 20.

The inclined positionof the slide has many advantages. In the first place it is approximately mparallel;;to;the;path;of astream: of ifallinglmate- "rial; @acted; 1111 011;- by a. series f superposed air mb asts; thus a uniform,action.oftheblastsupon -he- ,material is had whilethe .material follows its naturals-path. ,,In the second place pieces of w heavier imaterial, accidentally blown or carried by lighter material over the top of abafliecanfall ,mpon alowenbaflieiand be. returned to the slide; 5. thusupon neitherside of. the. baffles is the separaiwhich time the stratification of the material is complete. Inthethird place the height of the mma'chine in proportion'to the lengthof the path LTOf-Lthe material is reduced.

: ltnwill be evident thatlvarious modifications -may bean1adein the illustrative machine shown 1 v within the: scope: of the invention. For instance,

,1 several units may be used side by side.

.:-;I-Iaving:-described my invention, I claim:

1. 1'. In a separator for classifying a mixture of lumps :ofdifferent-specific gravity; an inclined slide, means to feed material to the upper end rofwsaidslide, said slide being interrupted by a ==series of superposed air blast ports for admitting blasts of air to the material as it descends by :gravity along said slide,-thereby spreading out the stream according to the specific gravity of the lumps; a baiiie structure in front of said slide comprising-deflector plates in front of and wholly below the respective air blast ports separated by open spaces opposite said ports, the space beyond said bafiie structure being substantially clear to permit the material blown beyond said baiiie structure to fall approximately parallel to said slide, said deflector plates being adapted to return lumps striking them toward said slide.

2. In a separator for classifying a dusty mixture of lumps of different specific gravity into the three classes: heavier lumps, lighter lumps, and dust; an inclined slide; means to feed material to the upper end of said slide; said slide being interrupted by a series of superposed air blast ports for admitting blasts of air from behind the slide to the material as it descends by gravity along said slide, thereby suspending the dust in the air currents and forming a stratified stream of material in which the lighter lumps are further from said slide, the space through which the lighter lumps are blown outward by said air blasts and through which said lighter lumps fall at a distance from said slide being free of ob struction; bafiles arranged in a downwardly inclined series in front of said slide to return the heavier lumps toward the slide, each baffle being of smaller height than the distance between successive air blast ports; outlet means for the dust laden air; and a dividing element spaced from the lower end of said slide to divide the stream of lumpy material.

3. Ina separator for classifying a dusty mixture of lumps of different specific gravity into the three classes: heavier lumps, lighter lumps, and dust; an inclined slide; means to feed material to the upper end of said slide; said slide being interrupted by a series of superposed air blast ports for admitting blasts of air from b hind the slide to the material as it descends by gravity along said slide, thereby suspending the dust in the air currents and forming a stratified stream of material in which the lighter lumps are further from said slide, the space through which the lighter lumps are blown outward by said air blasts and through which said lighter lumps fall at a distance from said slide being free of obstruction downwardly converging side walls along .said :slide. to concentrate the heavier lumps :to- :ward. the longitudinal midline;of said slide, said .airblast ports beinggraduated in size to conform to thenarrower space between said side Walls at 11,. ithevlowerr end of said slide; outlet means for the .cdustladen air; and a dividing element spaced :frorn. the lower end of said slide to divide the ilo ntionnfinal until theulast battle has been passed, at

, stream of lumpymaterial.

4.=In a separator for classifying a dusty. mixtide of lumps of different specific gravity into the three classes: heavier lumps, lighter'lumps, and dust; an inclined slide; means to feed material to the upper end of said slide; said slide being interruptedby aseries of superposed air blast ports for admitting blastsof air from behind the slide towthe material as it descends by gravity along said slide, thereby suspending the dust in the air iromsaid slide being free of obstruction; means .for concentrating the heavier lumps toward the longitudinal midline of said slide as they fall; .said .air blast ports being graduated in size in conformance with the smaller amount of material tobe retreated asthe stream descends; outlet means for the dust laden air; and a dividingelement spaced from the lower end of said slide to divide the stream of lumpy material.

5. In a separator for classifying a dusty mixture of lumps of difierent specific gravity into the three classes: heavier lumps, lighter lumps, and dust; an inclined slide; means to feed material to the upper end of said slide; said slide being interrupted by a series of superposed air blast ports for admitting blasts of air from behind the slide to the material as it descends by gravity along said slide, thereby suspending the dust in the air currents and forming a stratified stream of material in which the lighter lumps are further from said slide, the space through which the lighter lumps are blown outward by said air blasts and through which said lighter lumps fall at a distance from said slide being free of obstruction; means for concentrating the heavier lumps toward the longitudinal midline of said slide as-they fall, comprising a downwardly inclined series of bailles of diminishing size in front of said slide to return the heavier material toward said slide, each bafile being confined within the space between the levels of two adjacent air blast ports, said bafiles having blades extending toward said slide adapted to deflect material toward the longitudinal midline of said slide, said air blast ports being graduated of air to the material as it descends by gravity along said slide, thereby spreading out the stream according to the specific gravity of the lumps; a baffle structure in front of said slide comprising deflector plates in front of and wholly below the respective air blast ports separated by open spaces opposite said ports, said deflector plates being mounted on a common adjustable frame, the space beyond said baffle structure being substantially clear to permit the material blown beyond said bafile structure to fall approximately parallel to said slide, said deflector plates being adapted to return lumps striking them toward said slide.

'7. In a separator, an inclined slide, means to feed material to the upper end of said slide, said slide being interrupted by a series of superposed air blast ports for admitting blasts of air to the material as it descends by gravity along said slide, a downwardly inclined series of baiiles mounted upon a common frame in front of said slide to return the heavier material to the slide for retreatment, said frame being pivoted at one end to permit the frame to be swung out from said slide, and a dividing element spaced from the lower end of said slide to divide the descending stream of material.

8. In a separator for classifying a mixture of lumps of different specific gravity; an inclined slide, means to feed material to the upper end of said slide, said slide being interrupted by a series of superposed air blast ports for admitting blasts of air to the material as it descends by gravity along said slide, thereby spreading out the stream according to the specific gravity of the lumps; a baffle structure in front of said slide comprising deflector plates in front of and wholly below the respective air blast ports separated by open spaces opposite said ports, said deflector plates having transverse flanges at the top projecting toward said slide, the space beyond said baflle structure being substantially clear to permit the material blown beyond said bafile structure to fall approximately parallel to said slide, said deflector plates being adapted to return lumps striking them toward said slide.

9. In a separator for classifying a dusty mixture of lumps of different specific gravity into the three classes: heavier lumps, lighter lumps and dust; an inclined slide; means to feed material to the upper end of said slide; said slide being interrupted by a series of superposed air blast ports for admitting blasts of air from behind the slide to the material as it descends by gravity along said slide, thereby suspending the dust in the air currents and forming a stratified stream of material in which the lighter lumps are further from said slide, the space through which the lighter lumps are blown outward by said air blasts and through which said lighter lumps fall at a distance from said slide being free of obstruction; outlet means for the dust laden air; a dividing element spaced from the lower end of said slide to divide the stream of lumpy material, and one or more air blast ports below said dividing element for reclusting the lighter material.

FERDINAND C. MENK.

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