US2247385A - Abrasive separating and cleaning apparatus - Google Patents

Description

July 1, 1941.

R. B. HUYETT 2,247,385

ABRASIVE SEPARATING AND CLEANING APPARATUS Filed July 1, 1938 2 Sheets-Sheet l July 1, 1941. R. B. HUYETT ABRASIVE SEPARA'IING AND CLEANING APPARATUS 2 Sheets-Sheet 2 Filed July 1, 1958 J J4 J9 7 Elma/Whom Patented July 1, 1941 E T E T ABRASIVE SEPARATING AND CLEANENG APPARATUS Robert B. Huyett, Hagerstown, Md, assignor to Pangborn Corporation, Hagerstown, Md, a corporation of Maryland Application July 1, 1938, Serial No. 217,053

11 Claims.

This invention relates to apparatus for separating and classifying solid materials and it is more particularly concerned with apparatus for separating fine abrasive particles, sand, nails, wire and other extraneous material from abrasive.

In the blast cleaning of articles, the Work is subjected to the action of steel and other abrasives, usually within a closure. The abrasive is propelled at high velocity by air, or in more re cent years, by centrifugal wheels, and when it strikes castings or the like, foundry sand, nails, wires and other expedients used in the molding operation are removed from the work. Also, thin projections of the work itself are often removed. During the blast cleaning operation, a portion of the abrasive is also broken up through impact with the work into fine particles which are of no further use. These particles and also fine particles of molding sand will be hereinafter termed fines.

This mixture of widely variant materials, together with the abrasive which is capable of further use, falls to the bottom of the closure and is conveyed by an elevator or the like to an apparatus for cleaning the abrasive and separating the extraneous material and fines therefrom. Since the life of the abrasive propelling mechanism largely depends upon the quality of abrasive with which it is supplied, and the quality of cleaning is also alfected by the quality of the abrasive, the cleaning apparatus must effect as nearly perfect cleaning of the abrasive as is possible.

In my prior patents, No. 1,994,610, dated March 19, 1935, and No. 2,093,446, dated September 21, 1937, I have shown abrasive separating and cleaning apparatus of this general character and it is the major object of this invention to generally improve and refine the apparatus of my prior patents and to provide a novel abrasive cleaning apparatus which is compact and simple 1 in design and effects a highly eflicient cleaning of the abrasive.

A further important object is to provide an abrasive cleaning apparatus having a rotatable screening device and a stratifying plate, and em- Another object is to provide a novel fines separator in which the separating action may be adjusted at will without disturbing the size of the suction orifice through which the separating air current passes.

Further objects will become apparent as the specification proceeds in connection with the annexed drawings, and from the appended claims.

In the drawings:

Figure l is a front elevational view with parts in section of an apparatus embodying the invention;

Figure 2 is a vertical sectional View on an enlarged scale taken substantially along the line 2-2 of Figure 1, with the conveyor removed from the drum, and it also shows the skimmer plate assembly located in the bottom of the apparatus;

Figure 3 is a fragmental sectional View on an enlarged scale of one of the baffle members and illustrates a slightly modified form of construction and manner of mounting it on the screening member; and,

Figure 4 is a front elevational view of one of the baffle members.

With continued reference to the drawings, wherein like reference characters have been employed to designated like parts throughout the several views, and with particular reference to Figure 1, the apparatus is housed in a cabinet or casing H provided with a pair of aligned openings ill and II.

A cylindrical drum 92 extends through openings it and l l and is provided with a race 13 which rides on a pair of rollers it carried by a shaft journaled in bearings l5 adjacent the drum. An endless ribbon conveyor it of screw form extends from one end of the drum to the other and is reinforced by longitudinally extending strip-s ll which are preferably welded thereto. Also, secured to conveyor 55 are a plurality of supports it to which is secured a shaft l9. Shaft I9 is journaled in a bearing 2i and carries a drive sprocket 22 and the latter is adapted to be driven by a chain 23 from any suitable form of prime mover.

Drum i2 is, accordingly, mounted for rotation in a direction indicated by the arrow in Figure 1 and the abrasive to be cleaned is fed into an opening 2 provided in the left-hand end of the drum by way of a chute 25. The apparatus will normally be mounted adjacent the abrading apparatus and spent abrasive and debris from the apparatus will be lifted by an elevator and discharged into chute 25.

The left-hand end of the drum i2 is imperforate, with the result that abrasive and other debris is propelled from left to right as the drum is rotated and sufiicient agitation is effected to cause part of the dust or extremely fine material to be freed from the body of material as it cataracts in the drum. This fine material is removed by reason of a suction set up in the lower part of housing H by means to be later described. The sub-atmospheric condition existing in outer housing H causes air to be drawn in both ends of the drum and carry the fine material with it. The slight vacuum also prevents the escape of fine material through openings l6 and Il The portion of the drum within the housing is perforated in the manner to be hereinafter pointed out, with the result that the abrasive and fine material gravitates through the perforations, leaving the wire, nails and other large debris in the drum where it is ultimately conveyed out of the open end to a refuse chute 26 where it is conveyed away to a suitable receptacle for collection and disposal.

Referring more particularly to Figure 2, drum I2 is provided with a plurality of uniformly sized openings 28 through which the abrasive, the

foundry sand, broken up abrasive and other fines pass through a separating mechanism to be hereinafter described.

A plurality of circumferentially spaced longitudinally extending plates 29 are secured to the outer surface of the drum as by means of welding or the like so that the drum comprises a plurality of alternate perforate and imperforate sections.

An important feature of the invention resides in the baffle members to be now described.

In order to prevent elongated articles such as Wire, nails and the like from passing through openings 23, I provide a plurality of battle members St on the exterior of the drum, and they 4 overlie the perforate sections.

Each bafile member 3| is pivotally connected at 32 to the trailing edge of each plate 29, and in order to provide for the adjustable spacing. of the bafiie members from the drum, a pair of nuts 33 are welded to each baffle member in alignment with opening 34 therein. A screw 35 is threaded into each nut 33 and is adjustably locked in place therein by means of a lock nut 36.

In order to maintain screws 35 in contact with 7 plates 29 there are provided a pair of clamp members 37 for each baifie member 3! and they are generally U-shaped in form. The leading edges 33 of clamps 3'! bear against plates 29 and they are provided with trailing ends 39 which bear against baffle members 3!. The clamps are held 'in place by means of nuts M which are threaded on studs 42, the latter passing through openings in plates 29 and welded to the drum. Nuts 43 may be employed to secure plates 29 to the drum.

Therefore, by loosening lock nuts 36, screws 35 and nuts l may be manipulated to cause the bafile members to assume any desired angle with respect to the drum. Aside from the advantage of rocking the baflle members as a unit in order to vary their action upon the screened abrasive issuing from the drum, clamps 31 are of extreme importance in leveling the discharge edges of members 39. As clamps 31 are two in number they may be individually adjusted to vary the inclination of the discharge edges of the baffle members with respect to the horizontal, so that the abrasive will be discharged in a uniformly distributed sheet throughout its length, and a uniform discharge of abrasive onto plate 4% will be effected. Otherwise, most of the abrasive would find its way to one end of the baffle prior to discharge and upon discharge one end of plate 48 would receive a longer or excessive quantity of abrasive, and the other end would receive practically none.

From the structure so far developed, with the drum rotating in the direction indicated in Fig ure 2, the abrasive and other fine material will trickle through the perforated sections and be deposited upon the baffle members when the latter are disposed in approximately their lowermost position, and in order to give the abrasive a lift as rotation of the drum continues, each baifle member is provided with an outwardly inclining portion 45, a substantially tangentially disposed portion 56 and an inwardly directed lip 41. Therefore, during rotation of the drum, the abrasive will slide outwardly over portion 45 and come to rest in the space defined by portions 16 and 47. When each baflle member attains a position corresponding substantially to the nine oclock position in Figure 2, the abrasive will start to slide outwardly over surface 4?, and will be discharged in a thin sheet. The abrasive so discharged is deposited upon an inclined plate 48, which I term a stratifying plate.

In order to effect proper stratification of the abrasive and fines, it is necessary that the abrasive be discharged from plate 48 at considerable velocity. I am, nevertheless, able to locate plate 48 in close vertical proximity to drum l2 and still obtain requisite velocity of the abrasive because of the design of battle members 3] which lift the abrasive to an appreciable height before discharging it upon plate 43. This is a material advantage since in most installations of abrading apparatus, head room is an all important factor.

The head room required for any given abrading apparatus is directly affected by the height to which the abrasive must be lifted before it discharges upon the stratifying plate, and, therefore, by cutting down the height to which the abrasive must be lifted, it is possible to compactly locate the apparatus in tight quarters and also reduce the cost of the elevator used with the apparatus because it can be of minimum height.

It has been discovered that when abrasive mixed with smaller particles of abrasive and foundry sand travel down an incline at considerable velocity, a stratification of the large and small particles is effected at the lower edge of the incline because upon being discharged therefrom they assume different trajectories. In Figure 2 I have indicated the trajectory of the abrasive particles as 49 and the trajectory of the finer particles as 5|. Such stratification is assisted (intensified) by an air current, from right to left in Figure 2 and an air current is preferably used.

The stratified streams of abrasive and small particles or fines discharging over the stratifying plate are separated by novel mechanism and one which makes use of a phenomena discovered by me.

I have found that when a skimmer plate is employed to skim sand and fines from a falling stream of dirty abrasive, some of the particles have a tendency to continue by gravity past the orifice and go under instead of on top of the skimmer plate, with the result that they hug and follow the underside of the skimmer plate for some distance and then drop away from it. I take full advantage of this phenomena by providing a double skimmer plate assembly for cooperation with the falling stream.

Referring to Figure 2, as inclined primary skimmer plate 52 is rigidly mounted in cabinet H and is rigidly secured to the side walls thereof. Plate 52 has an upper edge 53 which catches some of the fines of stream 5! and it also cooper ates with the lower edge of the stratifying plate 58 to define the suction orifice. The lower end of plate 52 is aligned with the lower edge of an opening 55 provided in housing H and the separated fine material is discharged therethrough.

The skimmer plate assembly also comprises a secondary skimmer plate 55 whose lower end is aligned with an opening 55 through which the separated fine material gravitates. The separated fines fall through openings 54 and 55 into a chamber 51 which is closed by a door 53 pivoted on a pin 55. After a predetermined amount of material has collected in chamber 5? it swings door 58 about its axis and slides down an inclined way 5! into a chute 52 where it is conveyed to any suitable sort of bag or receptacle for subsequent removal. As shown in Figure 2, the right edges of the plates of the assembly terminate in sub stantially the same vertical plane.

Mounted on the upper end of plate 55 is an adjustable plate section 53 and it carries a pair of bolts 54 which are welded thereto. Bolts 65 extend through a pair of slots 55 in plate 55 and carry nuts 55 which may be loosened to permit section 53 to be moved in the plane of plate 55 toward and away from the falling streams of material. By adjusting section 53, the skimming action of the skimmer plate assembly may be varied at will.

It is very important in a separating apparatus of thischaracter to maintain an orifice of com stant size and the skimmer plate assembly of this invention makes it possible to achieve this result because plate 52 remains in fixed position and yet the separating characteristics of the skimmer plate assembly as a whole may be varied at will by loosening nuts 66 and adjusting section 53 to obtain the desired separating action. This adjustment does not in any way affect the position of plate 52 and, therefore, the distance between the upper edge of plate 53 and the lower edge of plate 55 remains unchanged. Plate 55 is also adjustable so as to decrease the gap between edge 53 and plate 53 for modifying the skimming action when the apparatus is handling very fine abrasives, and as this merely involves movement of plate 55 it likewise does not affect the size of the orifice. This adjustment may be effected by any suitable means as for instance by securing a slotted bracket 5'7 to each end of plate 55 and securing them to the end walls of the housing by means of cap screws 51a.

though the hugging phenomena is present when no cross draft is used, I preferably use a cross draft because it greatly augments the separating action.

The air currents for separating the fines from the abrasive may be set up in any desirable manner, but I preferably provide two or more suction conduits 58 at the front of the machine and they are aligned with openings in the front wall of housing H. They are preferably located some what below the upper edge 53 of plate 52 and preferably each conduit 58 embodies an adjustable blast gate 69 for varying the suction through the cleaning apparatus. The apparatus is placed in operation by connecting pipes 53 to a source of suction such as a fan or the like, and a dust collector is preferably inserted in the line for removing the extremely fine particles of dust that are separated from the abrasive and exhausted from the apparatus.

Drum I2 is rotated in the direction illustrated in Figures 1 and 2, and the unclean abrasive, which is laden with broken abrasive particles, molding sand and disintegrated sand particles, and also contains wire, nails, and other debris, is fed into the left-hand end of the drum, and as previously explained, it is propelled from left to right in Figure 1. During this operation, the materialis cascaded to some extent and some dust is freed from the material. The suction set up in the apparatus causes air to enter both ends of the drum and this dust is, accordingly, drawn through openings 28 in the drum and finds its way to the dust collector.

When the material has been propelled to the perforated section of drum l2 located in housing H, the abrasive and fines pass through openings 28 in the drum and are deposited upon baflle members 3!. Wire, nails and other elongated objects, that become up-ended and find their way into openings 28, strike baille members 3i and when the drum has rotated approximately 180 degrees, they drop back into the drum and are conveyed to chute 26.

The abrasive deposited on members 3! is lifted approximately 90 degrees and then is slowly discharged over the free ends thereof in a sheet-like stream and it is discharged upon stratifying plate 38 at considerable velocity.

The material is Stratified, as previously explained, into abrasive and fines streams, and the cross-draft set up by the suction conduits first traverses the abrasive stream and removes any fine particles therefrom that have not been properly Stratified and carries them into the fines stream. The fines are separated by the skimmer plate assembly in the manner previously described, some of the particles going over the top of plate 52 and gravitating down through opening 55, and some of the particles hugging the under side of plate 52 for a distance and then falling away by gravity and sliding down plate 55 and through opening 56. The upper edge of plate 53 also effects separation of any fine material that should fall sumciently far to be acted upon thereby. The extremely fine particles are not caught by the skimmer plates but are pulled directly into the suction conduits.

The fines gravitating from plates 52 and 55 ac cumulate in chamber 5? and when they have built up to a predetermined quantity, they will swing door 58 about its pivot and be automatically discharged into conduit 52.

In Figure 3 a modified form of drum lid is shown wherein the perforate and imperforate sections are formed directly in the drum. Also, bolts 42 are secured to bars H which are welded to the outside of the drum. In this form of the invention a pair of nuts 12 and 73 are threaded on each bolt 42 for holding clamps 3? in place, and the discharge portion of the baffle members forms a V having surfaces '54 and i5 for holding the abrasive.

From the foregoing, it is apparent that I have devised an abrasive separating and cleaning mechanism which is simple and fool-proof in design, is compact, and may be used where head room is very restricted, and yet which effects an extremely efficient separation of fines and other extraneous materials from the abrasive and delivers substantially pure abrasive to the storage hopper 72.

It is to be understood that if desired, in some instances, upper plate 52 may be omitted and plate 53 be relied upon to separate the fines stream from the abrasive stream, and by reason of the adjustments provided, its upper edge 65 may be moved toward and away from the abrasive streams, and also in an are when nut tile is loosened. Also, insofar as the action of plates 52 and 55 is concerned, drum 5? may be' located elsewhere in the apparatus and the unclean abrasive dropped from an elevator or the like directly upon a second plate similar to Q8 and located upwardly thereof. Also, the lower edge of the second plate may be located in substantial vertical alignment with the upper edge of plate id but spaced thereabove, so as to provide a second air gap, and air currents may be drawn therethrough for removing the dust and some of the fines at that point, prior to stratification of the particles on plate 38.

The invention may be embodied in other sp cific forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by United States Letters Patent is:

1. In an apparatus for cleaning abrasive of fines and other extraneous material, a housing; means for feeding a sheetlike stream of uncleaned abrasive downwardly in said housing; means for causing a current of air to flow across and through said stream in a direction substantially normal thereto, for separating fine particles of abrasive and other extraneous material from said abrasive as it passes downwardly in said housing; and a plurality of vertically spaced members, downwardly inclined in the direction of flow of the current of air, and disposed in said housing with their upper edges terminating in substantialy the same vertical plane adjacent said stream of uncleaned abrasive for catching said fine particles separated from said stream; and means for collecting the fine particles separated from said stream by said members.

2. In an abrasive cleaning apparatus, an inclined stratifying plate; means for depositing unclean abrasive upon the upper end of said plate; for causing it to gravitate downwardly in contact with said plate and be projected from the lower edge of said plate at considerable velocity and to stratify into a sheet-like stream of substantially clean abrasive and a substantially parallel sheet-like stream of fine particles; a downwardly inclined primary fine-catching plate-like member disposed below said stratifying plate and terminating in an upper edge adjacent said streams; a downwardly inclined secondary finescatching plate-like member disposed below said primary member terminating in an upper edge lying in substantially the same vertical plane as said upper edge of said primary member; and means for causing a current of air to traverse said streams of abrasive and fines substantially normal thereto, said members being downwardly inclined in the direction of the flow of said air current, said air current being so directed as to first traverse said stream of abrasive for removing any fines therefrom; and then traversing said stream of fines for causing the latter to be projected over the edges of said primary and secondary fines-catching members; and means for collecting said fines caught by said members.

3. The abrasive cleaning apparatus defined in claim 2, wherein said primary and secondary fines-catching members are disposed in parallel relationship to each other and are inclined at an angle which is greater than the angle of repose of said fines.

4. The abrasive cleaning apparatus defined in claim 2, wherein said primary and secondary fines-catching members terminate in straight edges which are parallel to each other and substantially parallel to said streams of fines and abrasive.

5. An apparatus for separating fines from abrasive, comprising means for feeding a sheetlike stream of unclean abrasive downwardly and allowing it to fall freely by gravity through a cross-current of air; a primary fines-catching plate-like member located adjacent said stream of unclean abrasive, said member inclining downwardly and away from said stream and in the direction of said cross-current of air, said crosscurrent of air removing fines from said stream and causing a portion of said fines to be projected over the upper edge of said primary finescatching member and causing the remainder of said fines to travel along the under surface of said member and a secondary fines-catching member inclining downwardly in the direction of said cross-current of air and disposed below said primary fines-catching member for catching said remainder of fines after they drop away from the under surface of the latter, said secondary member having an upper edge terminating substantially vertically below the upper edge of said primary fines-catching member; and means for collecting the fines caught by said primary and secondary members.

6. The apparatus defined in claim 5, wherein said primary and secondary fines-catching members are disposed substantially parallel to each other and terminate at their upper ends in straight edges disposed substantially parallel, and in close proximity to said stream of unclean abrasive.

'7. The apparatus defined in claim 5, wherein said primary and secondary fines-catching members are disposed in substantially parallel relationship and terminate at their lower ends in a pair of discharge edges over which said fines are delivered to a common fines-collector.

8. The apparatus defined in claim 5, wherein said secondary fines-catching member comprises a pair of complemental plate-like elements, together with means for adjusting the position of said elements with respect to each other, for varying the height of said secondary member and thereby varying the separating action thereof.

9. In an apparatus for separating fines from abrasive, a housing; an inclined stratification plate in said housing, means for feeding finesladen abrasive downwardly onto the upper end of said plate; a suction conduit at one side of said housing and below said plate, for drawing a current of air through the sheet-like stream of abrasive discharging over the lower edge of said plate for separating the fines therefrom; and a pair of superposed fines-catching members disposed in said housing below said plate and having their upper edges located in substantially the same vertical plane and in proximity to said stream of abrasive for catching the fines separated therefrom, said members being downwardly inclined in the direction of the air current, said upper member cooperating with said Stratification plate to define a suction orifice, said lower member having means mounting the upper edge thereof for movement toward and away from said stream, for adiustably varying the separating action of said members without varying the size of said orifice.

10. In an abrasive cleaning apparatus, an inclined stratification plate; means for depositing unclean abrasive upon the upper end of said plate, for causing it to gravitate downwardly in contact with said plate and be projected from the lower edge of said plate at considerable velocity and to stratify into a sheet-like stream of substantially clean abrasive and a substantially parallel sheet-like stream of fine particles; a primary fines-catching plate-like member inclined downwardly in a direction opposite to the direction of inclination of said stratification plate, and disposed below said Stratification plate, and having its upper edge disposed between said streams, for causing said stream of fine particles to be separated from said clean abrasive stream, and a secondary fines-catching plate-like member inclined downwardly in a direction opposite to the direction of inclination of said stratification plate, and disposed below said primary member for assisting in the separation of fine particles, said secondary member having its upper edge disposed in substantially the same vertical plane as the upper edge of said primary member.

11. The apparatus defined in claim 10, together with means for selectively adjusting said primary and secondary members toward and away from each other for varying the degree of separating action of said members.

ROBERT E. HUYETT.

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