US1005971A - Dry separator. - Google Patents

Description

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C. HERING.

`DRY SBPARATOR.

APPLIOATION FILED Nov. fr. 190e.

Patented Oct. 17, 1911.

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UNITED @BATES PATENT OFFICE.

CARL HERING, OF PHILADELPHIA, PENNSYLVANIA.

DRY SEPARATOR.

To all whom it may concern.'

Be it known that I, CARL HERING, a citizen of the United States, residing at Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented certain new and useful Improvements in Dry Sepa.- rators, of which the following is a specification.

rlhe object of this invention is to provide an apparatus for separating mixtures of particles, as for instance ores of'different specific gravities, by subjecting the particles to a current of air while they are in motion or are free to move. In the preferred form of the invention this is accomplished by passing a substantially horizontal current of air over the particles while they are rolling slowly down a large number of short inclined planes, alternating with short falls.

When a thin layer comprising a mixture of particles is shaken on a flat board and subjected to a current of air, the lighter particles are blown over the heavier ones and a certain separation is accomplished. In order that the separation may be effective the particles should all be capable of moving with freedom over each other, and they should have a movement of their own transverse or nearly so to the direction of the air current, in order that they may pass into different bins. Even in such case it is found that when the air current is suiliciently strong to produce a separation, it tends to blow the small particles of relatively high specific gravity away with the large particles of relatively low specific gravity, thus necessitating a more or less accurate sizing before concentration or a loss of the line material of high speciiic gravity. It is also found that the flat or flaky particles, eventhough of high specilic gravity, are apt to be blown away with the light ones, and this cannot be avoided by sizing. When the movement of the particles is produced by rolling them down a smooth plane, those light particles which are round are apt to acquire such velocity that the air current has little effect on them, and they therefore pass oli with the heavy particles.

. I have found that the above objections f vmay be overcome by subjecting the particles while in motion or free to move to a current 1 of air. of relatively low velocity but acting Specification of Letters Patent.

Application filed November 7, 1906.

ration.

Patented Oct. 17, 1911.

Serial No. 342,397.

:angle of repose is meant the steepest slope to which granular material may be heaped without rolling down to theV base. When vparticles are rolled down over themselves at this angle they generally tend to form lwhat may be called avalanches, thaty is, theywill pile up to a greater angle and then a mass of them will break olf and slide down together; this tendency I overcome by making the slopes very short and providing a large number of them, alternating with `short falls from one to the next. I find also that the line particles of relatively high specific gravity will then settle down on the rough surface where they are sheltered somewhat from the air current, and that the large, light particles being subjected to the full force of the air will then roll more freely over them, thereby producing a sepa- This is important, as the tendency is to blow the heavy, fine material out wit-h the lighter as above stated. By this means therefore I avoid the necessity of accurate sizing and of concentrating each size separately. The separation of the heavy, fine particles from the coarse, light ones may be further aided by diminishing the air currents over those parts of the bed where the mixture of these classes of particles tend to pass, as will be hereinafter explained. I also avoid the necessity of using any shaking or percussion mechanism, and am therefore enabled to make the inclined plane as large and long as maybe desirable; no moving parts except the feeding mechanism and the apparatus for producing air currents are required.

For a full understanding of the invention reference is made to the accompanying drawing wherein:

Figure l is a vertical section through a preferred form of separator; Fig. 2 is a face view of the same, the cover plate being removed; Figs. 3, 4, 5 illustrate various forms and constructions of grooves which may be employed; and Fig. 6 is a transverse section showing a modied form of cover plate.

Referring to the drawings, 1 represents an inclined bed or support, the upper surface of which is provided with parallel and substantially horizontal grooves or corrugations: as shown the grooves 3 are formed in a sheet 2 carried by the support 1, the construction of the apparatus in this respect being however immaterial. The inclination of the bed 1 should somewhat exceed the angle of repose of the material, as indicated in Fig. 3, wherein the dotted line a-a indicates the angle of repose, and b-b the inclination of the grooved bed. The apparatus is operative over a considerable range of inclinations, but the angle of inclination should in all cases be greater than the angle of repose of the material to be separated, and the grooves should be adapted to retain some of the material. In the form. of apparatus shown the material is fed to the top of the bed at one side thereof through a hopper L1 having a grooved feed-roller 5, and is discharged from substantially the entire width of the bed by a grooved roller 6, the particles being delivered to an apron 7 and passing thence to the various hoppers or bins 8, 9, 10, 11. The air current is confined by a cover plate 12, the portion of which remote from the line of feed is preferably flared upwardly as indicated at 13, Figs. 1 and 6. The purpose of the cover 12 and of the rollers 5, 6 is to provide an approximately air-tight casing for the bed for confining the air current to the vicinity of the particles to be separated.

The operation of the device as above described is as follows: The mixed particles are supplied to the upper portion of the bed at one side thereof from the hopper l, and subjected thereon to an air current substantially parallel to the grooves and therefore transverse to the general direction of movement of the particles. The grooves retaining a certain quantity of the material, there will be formed a large number of small inclinations 14, made by the material itself, over which the rest of the material will roll slowly. At the end of each small ineline, the particles will fall to the next, and during these short falls they will acquire only a very small velocity and will therefore be deflected to a greater extent by the air current. The manner in which material fed from the hopper 4c tends to be separated during its downward movement is indicated by the dotted lines in Fig. 2; in practice it may sometimes be preferable to make the inclined bed shorter and to pass the middlings through the same or a similar separator.

In order to prevent the air current from blowing the material out of the grooves, these may be made relatively deep as shown in Fig. 4; or the bottoms of the grooves may be roughened by cementing sand therein or by other means as indicated at 15 in Fig. 5. After the grooves are once filled the air current does not blow out the material.

I prefer to use suction rather than pressure for establishing the air current. The apparatus is then dustless, and the dust is more easily collected in the usual bags; moreover the front edge of the inclined air channel is then always open for inspection. Suction applied at the side of the bed where the lighter particles tend to pass also enables a more uniform air current to be established over the whole surface, and the current is more free from eddies.

In order to render still more eective the separation of the fine, heavy particles from the coarse, light ones, and to prevent any considerable proportion of the ne, light material from being drawn into the dust bags, I prefer to Hare the cover plate as shown at 13 in Figs. 1 and 6, making the air channel relatively small in cross sectional area over the parts where the heavy particles pass down, and relatively large over the path of the lighter particles. Thus the air current will have its highest velocity over the heavy particles and will gradually diminish in velocity toward the other side of the bed, thereby depositing the lighter particles which are apt to be floated by the air, and causing them to roll down under the best conditions for separation.

Instead of a steady current of air I may use a variable or intermittent air current or pu`s of air. Such variations or pus may be produced in the blower by the disposition of the blades therein or in any other convenient way; for instance in Fig. 6 I have shown a rotary fan or blower 16 connected to the suction side of the casing, and provided with a single blade 17, the eect being the production of an intermittent air current or one of variable velocity. Or I may approximate the effect of puffs by corrugating the upper side of the air channel perpendicularly to the direction of the air current, as shown at 18 in Fig. 6. A steady air current will thereby be converted into one having alternately greater and less velocity as it passes through the contracted and widened channels produced by these corrugations. rIhus any smaller particles which may have floated will have opportunities to settle.

While the concentrator will operate without any movement of the inclined bed, it may at times be desirable, as for instance for the finest dust, to slightly shake or tap the bed. This may be effected by a simple arrangement, as indicated at 19 in Fig. 1. As the operation of the apparatus is sensitive to variations of the air current, I may connect a pressure gage to any convenient part of the channel as shown for instance at 20 in Figs. land 3, as an aid in keep-ing the pressure constant and in producing the same pressure at any future time.

The grooves should be adapted to the character of the mixture to be separated, and in general the grooves should be narrower for finer grained materials and wider for coarser mixtures.

An advantage of this apparatus is that the separated materials pass from the concentrator in the form of a continuous stream of particles along the whole of the lower edge, varying with more or less pronounced gradations from the best concentrates at the one side to the best tailings at the other, with the middlings between them; it is therefore within the easy control of the operator to divide this stream into concentrates, middlings and tailings at any two points desired, thereby obtaining concentrates of any desired richness, tailings of any desired leanness, and correspondingly larger or smaller amounts of middlings which are again separated.

A further advantage of the apparatus is that mixtures of three or more materials may be separated in the same device.

I claim:

l. Apparatus for separating mixtures comprising an imperforate inclined bed, grooves thereon disposed transversely to the direction of inclination of the bed, means for feeding material to the higher portion of the bed, and means for establishing an air current above said bed longitudinally of said grooves.

2. Apparatus for separating mixtures comprising an imperforate inclined bed, the inclination of the bed exceeding the angle of repose of the particles, grooves thereon disposed transversely to the direction of inclination of the bed, means for feeding material to the higher portion of the bed, and means for establishing an air current above said bed longitudinally of said grooves.

3. Apparatus for separating mixtures comprising an imperforate inclined bed, grooves thereon disposed transversely to the direction of inclination of the bed and adapted to retain portions of the mixture in the form of separate parallel bodies having surfaces at their angle of repose, means for feeding ma# terial to the higher portion of the bed, and means for establishing an air current above said bed longitudinally of said grooves.

t. Apparatus for separating mixtures comprising an imperforate inclined bed, grooves thereon disposed transversely to the direction of inclination of the bed, a casing providing a confined space `above said bed, means for feeding material to the higher portion of the bed, and means for establishing an air current above said bed longitudi nally of said grooves.

5. Apparatus for separating mixtures comprising a bed inclined in the direction of delivery of the particles and provided with means for retarding the downward movement of particles thereon, a casing providing a confined space above said bed, substantially air-tight feed and discharge devices for said casing, and means for establishing a transverse air current through said casing.

6. Apparatus for separating mixtures comprising a bed inclined in the direction of den livery of the particles and provided with means for retarding the downward movement of particles thereon, means for feeding materiai to the upper portion of said bed, a casing providing a confined air space above said bed and flaring outwardly in the direction of the transverse air current above a portion thereof, and means for establishing a transverse air current through said casing.

7. Apparatus for sep arating mixtures comprising an imperforate inclined bed, means for feeding material to the higher portion of the bed, means upon the surface of the bed for retarding the downward movement of the particles, means for establishing a transverse air current above said bed and substantially parallel to the surface thereof, and means for varying the velocity of said air current over portions of the bed.

8. Apparatus for separating mixtures comprising an imperforate inclined bed, means for feeding material to the higher portion of the bed near one side thereof, means upon the surface of the bed for retarding the downward movement of the particles, means for establishing a transverse air current above said bed and substantially parallel to the surface thereof, and means for reducing the velocity of the air current over the side of the bed remote from said feeding means.

9. Apparatus for separating mixtures comprising a bed inclined in the direction of delivery of the particles and provided with means for retarding the downward movement of particles thereon, means for feeding material to the upper portion of said bed, a casing providing a confined space above said bed and provided with longitudinal recesses, and means for establishing a transverse air current through said casing.

10. Apparatus" for separating mixtures comprising an imperforate inclined bed, means for feeding material to the higher portion of the bed, means upon the surface of the bed for retarding the downward movement of the particles, and means for establishing a transverse air current of vary ing velocity above said bed and substantially parallel to the surface thereof.

11. Apparatus for separating mixtures comprising an imperforate bed arranged at an inclination greater than the angle of repose of the mixture delivered thereto, means tudinally of said parallel bodies and subl0 for retaining on said bed a portion of the stantially parallel to the surface of the bed. mixture in the form of separate parallel In testimony whereof, I afx my signature plodies disposed transilersely of1 thefbed and in presence of two witnesses.

avmg surfaces at t eir ang e o repose, means for feeding material to the upper por- CARL HERING' tion of said bed and discharging it from the Witnesses: lower portion thereof, and means for estab- VIOLA E. IRWIN, lishing an air current above said bed longi- WALTER E. WEYL.

Copies of this patent may be obtained for ve cents each, by addressing the Commissioner of Patents, Washington, D. C.

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