Blast machine sealing means

May 1, 1962 r. _M. leliaert 3,031,802

BLAST MACHINE SEALING MEANS

Filed Nov. 29, 1960 4 Sheets-Sheet 1

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May 1, 1962

R. M. LELIAERT

BLAST MACHINE SEALING MEANS

3,031,802

Filed Nov. 29, 1960 ₄ Sheets-Sheet 2

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May 1, 1962

3,031,802

R. M. LELIAERT

BLAST MACHINE SEALING MEANS

Filed Nov. 29, 1960

Sheets-Sheet 3

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May 1, 1962

3,031,802

R, M. LELIAERT

BL,AST MACHINE SEALING MEANS

Filed Nov. 29, 1960

Sheets-Sheet 4

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3,031,802

Patented May 1, 1S62

United States Patent Office

3,031,802

BLAST MACHINE SEALING MEANS Raymond M. Leliaert, South Bend, Ind., assignor to Beil Intercontinental Corporation, South Bend, Ind.

Filed Nov. 29, I960, Ser. No. 72,360

Claims. (Cl. 51—9)

This invention relates to blast machines, such as are used for abrading, polishing, peening, cleaning, surface hardening, and the like. Specifically, the invention relates to improved means for sealing the passageways or openings through which workpieces are admitted or discharged from the chambers or enclosures within which the blasting operations are performed by machines of such types as are shown for example in U.S. Patents 2,338,591, 2,460,989 and 2,924,911.

Such blasting machines as are used for example in descaling, deburring, deflashing, or cleaning and polishing of weldments or castings of metal and other materials, as well as for shot-peening and similar operations, require the use of effectively sealed cabinets or enclosures surrounding the blasting operations, both to protect attendant personnel and to prevent loss or waste of the shot or other abrasive media. It has long been a problem to effectively seal access holes and workpiece inletoutlet openings in such machines especially for working upon long workpieces which must be progressively fed through the blast chamber, or when fed by a conveyor moving workpieces continuously through the blast chamber; and previously developed mechanical sealing means such as flaps of rubber, labyrinth baffles, and so: forth, all have serious shortcomings. The problem is especially difficult when using relatievly heavy iron or steel shot as the blasting media, because under such circumstances the prior art seal devices do not perform efficiently even when new, and, tend to deteriorate in use under the impact and abrasion effects of the blasting particles.

In my recently issued Patent No. 2,924,911,1 disclosed an improved type of seal for such purposes, which I call a magentic type seal; but it is an object of the present invention to provide a still further improved type of magnetic seal means for sealing blast enclosures through which are moving workpiece carrying conveyors of certain shapes of long workpieces such as H beams, channels, I beams, and the like, which will operate in improved manner to prevent escape of the blasting media from the enclosures.

Another object of the invention is to provide an improved sealing means as aforesaid which comprises a sealing curtain of novel form which is self-sustaining and conformable with improved efficiency to a wide variety of moving conveyor or workpiece shapes.

Other objects and advantages of the invention will appear from the specification hereafter and the accompanying drawings wherein:

FIG. 1 is a vertical sectional view of a shot blasting machine utilizing one form of the sealing means of the invention;

FIG. 2 is a fragmentary sectional view, on enlarged scale, taken on line II—II of FIG. 1;

FIG. 3 is a fragmentary sectional view taken along line ΠΙ—III of FIG. 2;

FIG. 4 is a sectional view taken on line IV—IV of FIG. 3;

FIG. 5 is a view corresponding to FIG. 2 but of another form of sealing means of the invention;

FIG. 6 is a section taken on line VI—VI of FIG. 5;

FIG. 7 is an enlarged scale sectional view of one of the seal components, taken on line VII—VII of FIG. 8 and illustrating the magnetic operation thereof;

FIG. 8 is a fragmentary longitudinal sectional view, partly in elevation, of a seal component of the invention;

FIG. 9 is a view corresponding to FIG. 8, but of a modified form of sealing component of the invention;

FIG. 10 is a view corresponding to FIG. 3 but showing use of another form of sealing component; and

FIG. 11 is a section taken on line XI—XI of FIG. 10.

As set forth in my prior patent 2,924,911 it has been discovered that where a ferrous or other magnetizable particle media is being used in a blasting operation, an improved sealing arrangement may be provided by using 10 the media itself as the sealant. In such case the magnetizable quality of the abrasive media is utilized by subjecting it to the effects of a magnetizing arrangement adjacent the opening to be sealed, thereby setting up a magnetic field across the opening and causing the blast 15 media particles to accrete and close off the opening. The present invention utilizes the same phenomenon, but provides a supplemental blast media support, making the seal more effective in connection with deeply recessed workpieces or conveyors moving through the machine 20 cabinet.

More specifically, FIGS. 1-4 illustrate an example of a blast chamber sealing means of the invention, which is arranged especially for workpieces having deep vertical recesses such as in the case of the I beam or H beam 2® type; and wherein a machine housing 10 is provided with a centrifugal throwing wheel 12 mounted in its upper deck portion. The wheel 12 is fed abrasive or other blast material from a hopper 14 through a chute 16 and elevator 18. The lower side walls of the enclosure 1® incline to direct the spent blast media to flow into a troughlike bottom portion 19 of the enclosure, for delivery to the feed elevator 18 by means of a screw conveyor as indicated at 29.

As shown in FIG. 1, the housing 10 is provided with an opening or vestibule 22 at each end thereof so that a working carrying conveyor or a workpiece as indicated at 24 may be progressively fed therethrough. Hence, the lengths of the workpieces to be treated are not limited by the size of the cabinet 1®. To be effective, the sealing means for these openings must closely surround and complement the sectional forms of the conveyor and/or workpieces; and in order that the seals be not limited to use with any one size or sectional shape of workpiece, they must be flexible and capable of adapting themselves to ⁴⁵ fit variously shaped and dimensioned workpieces while still providing optimum sealing effects.

In accordance with the present invention, flexible magnetized curtain means are disposed to close the openings while permitting free entrance and exit of workpieces ⁵⁰ therethrough. The magnetized curtain means include flexible magnetizable bristle-like components which magnetically attract the ambient blast media particles and cause them to accrete against the curtain components and between them and the workpieces passing therethrough, ⁵⁵ thereby forming an overall curtain of the media. I have found that such curtains of abrading media formed upon skeletons of flexible support members, provide intimate and tight and very effective seals against loss of blast media from the enclosure, while the workpieces and/or ⁶⁰ feeding conveyor may be readily pushed through the curtains while displacing only the magnetized particles they locally encounter. The blast media particles surrounding the sides of the workpieces maintain close, firm seals therearound which automatically shape and reshape them®5 selves to objects being thrust therethrough without leaving openings through which media may escape.

As shown in FIGS. 1-4, the flexible support members may be formed of coiled steel spring form as indicated at 26 and are anchored at their root ends in sill plates 70 2S—28 carried by top and bottom non-magnetic steel elements 30—30. The frame structure is completed by non-magnetic side plate members 31—31, assembled as

3,031,802 by means of screws 32, thus framing the workpiece access opening of the cabinet vestibule 22. The springs 26 are thereby disposed in cantilever extending relation from the top and bottom levels of the framed opening towards the horizontal center plane of the opening; and thus the upper and lower curtains of springs mutually abut at the center when no workpieces interfere. However, as shown in FIGS. 1, 3, when a workpiece such as shown at 24 is thrust into the opening the springs of the curtains flex and conform to the sectional shape of the workpiece while permitting it to be moved in any desired direction relative to the framed opening. Preferably, the workpiece will be supported upon rollers or the like as shown at 34 so as to be disposed to run through the framed opening at approximately its center, but it will be appreciated that the flexibility of the curtain springs v/ill permit the curtains to adjust to any other disposition of the workpieces.

Means for magnetizing the springs 26 may be provided to comprise permanent magnets of bar form as indicated at 36, 38 disposed flatwise across the top and bottom sills of the frame piece 30, which are in turn capped (top and bottom) by pole pieces of metal as indicated at 40—40. Vertically standing pole pieces 42—42 are also provided at opposite sides of the opening (FIG. 2) and are insulated from the frame 30 by wooden spacers 43—43. Thus, magnetic flux paths as indicated at 44 (FIG. 2) are established so as to magnetically saturate the curtain springs 26. This magnetization of the curtain springs causes them to attract and hold the blast media particles which come into contact with the curtains; the springs being preferably relatively staggered and disposed to provide curtains of substantial depths as shown in FIG. 1 comprising labyrinths of magnetized bristle-like devices which function to trap any blast media impinging thereagainst.

FIGS. 5 and 6 correspond to FIGS. 2 and 3 but show an alternative disposition of the curtain springs 16 whereby they are mounted to extend horizontally from cantilever mountings at the opposite side walls of the frame 30 toward the center vertical plane of the opening. Thus, the springs 16 are better adapted to extend into deep lateral recesses; for example, into brush-sealing contact with the web portions of H or I beam type workpieces as indicated at 50. Thus it will be appreciated that various alternative arrangements for supporting and directing the curtain springs toward the workpieces to be handled may be employed. In any case, the object is to substantially fill the blast cabinet access opening with a curtain of resilient bristle-like devices which v/ill permit workpieces to be moved therethrough and which are magnetized to induce accretion of shot blast media thereon so as to develop a barrier permeable to workpiece travel but substantially impermeable to blast shot escape.

Whereas the spring devices 16 may be of simple leaf or coil spring form and magnetized as explained hereinabove, their magnetization characteristics may be provided and/or enhanced by using a hollow type spring and filling them with a magnetizing agent such as a plastic magnetic material. For this purpose a material known in the trade as “Indox 1” mixed with a plastic such as the Goodrich Corp, product known as “Koroseal Magnet Type 1” may be employed to provide a suitable vinylceramic magnet mixture. FIGS. 7-8 of the drawing herewith illustrate at 52 disposition of such a magnetic material within the coil springs 26; and it will be appreciated that the plastic nature of the filler material 52 will permit the springs to flex for the purposes explained hereinabove while at the same time providing active magnetization of the curtain elements for entrapment of blast shot as explained hereinabove. FIG. 9 illustrates an alternative arrangement wherein magnetized marbles 54 of metal or ceramic or the like are loaded within coil springs 26 to effect magnetization thereof also without interfering with their flexibility characteristics.

As shown in FIGS. 10 and 11, the curtain spring devices may be provided in the form of batteries of brushes comprising bristles of magnetizable spring steel or the like arranged in staggered gang relation; the bristles being rooted in clamp devices 62 carried in channels 64 which are spaced apart by steel bars 66. Thus, the assemblies 5 are readily welded or otherwise suitably fastened to the aperture frame structure 68. As explained hereinabove in connection with FIGS. 1-3, the bristles of the brushes 69 may be magnetized by mounting permanent bars 70, 72, 74 above and below the top and bottom sills respec10 tively of the frame 68; and by providing top and bottom pole pieces 76, 78, and side pole plates 80—SO. Insulation cheek plates of aluminum alloy or the like as indicated at 82—82 may also be provided for the work loading aperture; and being of non-magnetic material v/ill 15 not interfere with proper flexing motions of adjacent bristles of the magnetized curtain.

As shown in FIG. 10, the magnetic curtain vestibule covering the workpiece loading aperture 84 of the blast cabinet may be provided if desired with a supplemental 20 vestibule 85 enclosing a plurality of shot clean-off brushes

86. The brushes 86 may comprise bristles formed of nylon or the like, arranged to extend across the outer opening 88 of the magnetic sealing vestibule in such manner as to scrub against the workpieces as they pass by, 25 to scrape off any blast shot still clinging to the workpiece.

Thus, the recovered blast media may be collected below the supplemental vestibule 85 and returned to the blast operation by any suitable means.

It will of course be appreciated that although only a 30 few forms of the invention have been shown and described in detail, various changes may be made therein without departing from the spirit of the invention or the scope of the appended claims.