NZ273149A - Regenerating media for blasting equipment - Google Patents

Description

New Zealand No. 273149 International No. PCT/US94/09411 TO BE ENTERED AFTER ACCEPTANCE AND PUBLICATION Priority dates: 17.08.1994 Complete Specification Filed: 17.08.1994 Classification:^) B24D3/00 Publication date: 25 November 1998 Journal No.: 1434 new zealand patents act 1953 COMPLETE SPECIFICATION Title of Invention: Method of regenerating media for use in pressurized device Name, address and nationality of applicant(s) as in international application form: ADVANCED RECYCLABLE MEDIA SYSTEMS, INC., 5400 South Miami Boulevard, Suite 154, Durham, North Carolina 27703, United States of America ( INTELLECTUAL PKukWY Of-'RcTI OF N1. I 16 sep 1998 received 1 METHOD OF ^REGENERATING MElTIX FOR USE IN PRESSURIZED DEVICE This invention relates to a method of remaking and/or regenerating media, for use in suitable blasting 5 equipment, so that such remade and/or regenerated media may be again used in suitable blasting equipment and propelled, via a pressurized air stream, against a surface of an object to dislodge and/or absorb any contaminant thereon. The contaminant or contaminants to be removed 10 may include any foreign substance attached to or carried by the surface such as hazardous materials, soil, grease, oil, paint, soot, solvents and other objectionable deposit.;. The invention also relates to a method of minimizing waste associated with removing contaminants or 15 debris from a desired surface.

Background of the Invention The present invention is particularly directed at remaking and/or regenerating media which is commonly referred to as "composite media" which comprises a 20 plurality of discrete particles of an abrasive component mixed with and attached to a carrier component. The abrasive component and carrier component are selected to provide desired wear of the composite media, during use, to expose additional underlying abrasive media and to 25 enhance cleaning of the surface being treated. The composite media facilitates feeding of the blasting media and results in deeper penetration of the blasting media into the surface being treated. A number of known blasting media compositions, which are particularly 30 adapted for remaking and/or regenerating, are disclosed in United States Patent No. 5,234,470 issued August 10, 1993 to William R. Lynn and Wilfred P. Parent.

Summary of the Invention: Wherefore, it is an object* of the invention to 35 facilitate recycling, rebuilding, regenerating, These relate to at least the preferred embodiments of the invention. 273149 recombining, reusing and/or repairing of the blasting media on site to minimize the waste associated with a blasting operation and maximize efficient use of the blasting media.

Yet another object* of the invention is to provide a method of collecting, screening, sifting and/or separating of the used composite blasting media from the debris and other contaminants and to clean and recycle the composite blasting media to produce new granules of the composite 10 blasting media which each contain additional abrasive component and/or carrier component.

A further object*of the invention is to select the carrier component to be capable of physically carrying the abrasive component while controlling dust and prolonging 15 the integrity of the abrasive component. As the composite blasting media begins to wear, the composite blasting media is recycled by adding additional abrasive component and/or carrier component to the used composite blasting media and this mixture is formed into new larger granules 20 each containing the carrier component and the abrasive component.

Still another object* of the invention is to add a liquid or solid substance or a bacteria or fungus to the composite blasting media which will assist the composite 25 blasting media in decomposing or decompose the absorbed contaminant and debris over a desired period of time. The substance is typically added just prior to use.

The present invention relates to a method of recycling a used composite blasting media after being 3 0 propelled through desired blasting equipment, said composite blasting media comprising a plurality of granules which each contain a plurality of discrete particles of an abrasive component physically interconnected with one another by a carrier component, 35 which is a solid at room temperature, * These relate to at least the preferred emboiments of the i nventi on. 0l'hLu \ OH Ni. .t: *t328 received 273149 WO 96/05021 PCT/US94/09411 said method comprising the steps of: collecting the composite blasting media after at least one blasting cycle; nixing at least one of additional abrasive 5 component and additional carrier component with the collected composite blasting media; and forming the mixture of composite blasting media into a plurality of granules each containing a plurality of discrete particles of the abrasive component physically 10 interconnected with one another by the carrier component.

The present invention further relates to a method of forming a recyclable granulated composite blasting media for use in treating a surface to remove undesired contaminants therefrom, said composite blasting media 15 being suitable for being propelled via a fluid stream through desired blasting eguipment; said method comprising the steps of: forming granules of the composite blasting media, each said granule comprising a plurality of 20 discrete particles of an abrasive component physically interconnected with one another by a carrier component, which is solid at room temperature, the carrier component being selected to wear, during use of the composite blasting media, at a rate so as to continuously expose 2 5 additional underlying abrasive particles on an exterior surface of that composite media particle, but not at a rate to allow the premature separation of the abrasive particles from an exterior surface of that composite media particle; 3 0 propelling the recyclable composite blasting media through desired blasting equipment to treated a desired surface; collecting the composite blasting media with a collecting device and cleaning the collected composite 09:04:23 blasting media, after at least one blasting cycle, with a cleaning device; and reforming the composite blasting media into a plurality of granules each containing a plurality of 5 discrete particles of an abrasive component physically interconnected with one another by a carrier component.

Finally, the present invention further relates to a method of recycling a used composite blasting media after being propelled through desired blasting equipment, said 10 composite blasting media comprising a plurality of granules which each contain a plurality of discrete particles of an abrasive component physically interconnected with one another by a carrier component, which is solid at a temperature below room temperature, 15 said method comprising the following steps all occurring at a temperature below room temperature: collecting the composite blasting media after at least one blasting cycle; mixing at least one of additional abrasive 20 component and additional carrier component with the collected composite blasting media; and forming the mixture of composite blasting media into a plurality of granules each containing a plurality of discrete particles of the abrasive component physically 25 interconnected with one another by the carrier component.

These and other objects of the invention will better understood by those skilled in the art by having reference to the appended drawings and the following description.

Brief Description of the Drawings: 3 0 The invention will now be described, by way of example, with reference to the accompanying drawings in which: Figure 1 diagrammatically shows a feed mechanism for supplying the blasting media to the blasting nozzle; 09:04:23 96/05021 PCT/US94/09411 Figure 2 diagrammatically shows one embodiment of the method of collecting and recycling the composite blasting media; and Figure 3 diagrammatically shows a second embodiment 5 of the method of collecting and recycling the composite blasting media.

Description of the Preferred Embodiments Suitable blasting equipment, for propelling blasting media against a desired surface is shown in Figure 1. As 10 such equipment is well known in the art, it is only briefly discussed hereinafter. The improved composite media 40 is supplied to and contained within a hopper 44. An outlet of the hopper is connected with a positive feed mechanism 42 such as an auger driven by a motor 41. The 15 auger conveys the blasting media 40 through a one way valve 4 3 toward a T-fitting 45. Pressurized air is supplied from air pressure source 46 to a second inlet of the T-fitting 45. The pressurized air in the conveying blasting media combined with one another and are mixed and 20 conveyed out an outlet of the T-fitting 45 toward the nozzle 47 for a discharge against a desired surface 48.

With reference to Figures l through 3, the method of recycling the composite blasting media according to the present invention will now be described in detail. The 25 regenerated composite blasting media according to the present invention is unique because the abrasive component is physically (mechanically, chemically, etc.) supported or held by the carrier component. Further, the carrier component can be selected to control the generation of 30 dust and prolong the useful life, e.g. the integrity, etc., of the abrasive component as the carrier component can absorb much of the impact energy upon striking the surface being treated. As the media begins to wear, additional abrasive components are continually exposed. 35 Once the carrier component has been sufficiently worn. 09:04:23 i.e. after the blasting media 50 has been reused through the blasting equipment a sufficient amount of times (e.g. 5-9 cycles) and discharged via the nozzle 47 against the surface 48 to be treated, the used blasting media is 5 collected (step Sl)f by a suitable collection means 100. One such suitable collection means would, for example, be an operator sweeping the media particles into a pile and collecting the same with a dust pan or, preferably, using some sort of vacuum device to suck up all of the blasting 10 media particles 50. Once the media particles are collected (Figs. 2 and 3), they can be either screened or sifted (step S2) to separate the small particles, fines and other contaminates and debris 110 from the recyclable composite blasting media. If desired, the screening step 15 can be replaced or used in combination with a washing step (step S2A) to wash away and/or dissolve any matter that may be soluble in water or some other desired cleansing solution 112. if the washing step is employed, the washed composite blasting media is typically air dried or 20 squeezed (step S2B) after the washing step to remove the residual liquid and/or moisture 114.

Next, the cleaned composite blasting media is mixed (step S3) with at least one of additional abrasive component and/or carrier component to replenish the 25 consumed, fractured, abraded and/or spent abrasive component and/or carrier component. In Fig. 2, this mixture is typically heated (step S4) to a desired temperature, depending upon the composition of the carrier component, to melt the carrier component into liquid form 30 and physically entrap, encapsulate and/or bond the added abrasive and/or carrier components with the recycled abrasive and carrier components.

The heated mixture of the composite blasting media is then thoroughly mixed to achieve a uniform mixture of the 35 abrasive and the carrier components and allowed to 09:04:23 solidify (step S5). Thereafter, the solidified composite blasting media is extruded (step S6) through suitable extruding equipment, such as an extruder manufactured by American Mapla Corp., 283 South Bypass, Mcpherson, Kansas.

The extruded composite blasting media is finally ground (step S7) by suitable grinding equipment, such as a grinder manufactured by Nelmor Plastic Machinery of Nuxbridge, Massachusetts (model #G1012M1), into a plurality of granules of a desired particle size, each 10 granules comprising a plurality of abrasive components and carrier components physically interconnected with one another. The size of the granules is selected according to the blasting application for which the particles will be used.

Alternatively, depending upon the kind of material used as the carrier component, (Fig. 3) the recycled composite blasting media is collected (step SI), screened or sifted (step S2), and, if desired, washed (step S2A) and dried (step S2B), and then additional abrasive 20 component and/or carrier component may be is added to the cleaned composite blasting media (step S3) , the same as with the previous embodiment. Thereafter, the mixture of the abrasive and carrier components is allowed to react and chemically bond with one another (step S4) . The 25 chemically bonded composite blasting media is then allowed to set or solidify (step S5) , is extruded (step S6) by suitable extruding equipment, and finally ground (step S7) by suitable grinding equipment into granules of a desired particle size.

If a foam is used as a carrier component of the composite media, water or another liquid may be added to and absorbed by the foam carrier component (step 1A) which will cause the foam carrier component to swell to a larger particle size (Fig. 3). The swollen foam is much easier 35 to separate in the screening or sifting step (step S2) as 09:04:23 96/05021 PCT/US94/09411 the contaminates and debris, such as lead paint which are either not soluable or readily soluable in water, readily pass through the screen or other sifting member while the swollen foam carrier component, of a sufficiently larger 5 size, containing the abrasive component is readily retained. The screened and swollen composite blasting media can then either be dried or squeezed, to remove the water or other cleaning fluid therefrom, before the composite blasting media is mixed with additional abrasive 10 component and/or carrier component.

In attempt to produce and recycle/recombine media on site, an experiment was performed by the inventors. Mixtures of hydrophilic polyol, gypsum and water were tried in various experiments. The gypsum proved to be 15 very difficult to bond and dusted unacceptably when used in a blasting equipment. Accordingly, further tests with gypsum were abandon in favor of garnet and steel shot. In a unique two step portable mixture was developed by the inventors and they discovered that garnet, mixed with the 20 hydrophilic polyol and water procedure, worked well.

If the composite blasting media comprises a slurry of water, or some other freezable liquid, and an abrasive component, the slurry is completely mixed and then frozen to solidify the mixture. Thereafter, the frozen liquid 25 can then be ground into a plurality of discrete particles each containing the carrier component (e.g. water) and the abrasive component. In such grinding application, the grinder is typically located in a room which is maintained at a temperature below the freezing temperature of water 30 or another liquid used as the carrier component, e.g. 0°C, to minimize any melting of the frozen slurry.

If a frozen liquid is used as the composite blasting media, preferably the blasting will occur in a temperature controlled or a chilled environment (e.g. below 0° C). 35 Such an environment will minimize any melting of the 09:04:23 96/05021 frozen liquid during use and to facilitate collection of tlie used blasting media, cleaning, and recycling of the blasting media.

Alternatively, it would be possible to impregnate or 5 mechanically force the abrasive component into a pliable carrier component, such as a soft plastic (e.g. high density polyethylene; low density polyethylene; polypropylene; poly(vinyl chloride); polystyrene; ply(acrylonitrile-butadiene-styrene); and polyurethane), 10 putty, etc. In order to recycle the plastic or putty containing an abrasive component, the fines, the contaminates and the other debris is first separated from the reusable media and then additional abrasive and/or carrier component, e.g. soft plastic and putty material, 15 is added to the collected mixture. The abrasive is then impregnated or mechanically forced into the soft plastic or putty, thoroughly mixed, extruded, if necessary, and finally reground into particles of a desired particle size for further use.

It is possible to use an air washer to clean the collected blast* g media (step S2) . One such suitable air washer is manulat turer by Invincible Air Flow Systems of Dover, Ohio (jV.Jdel no. 700-10) . It is also possible, depending on the type of debris or abrasive material used, 25 to use a magnetic separator to separate the fines, the debris and the contaminates from the recyclable composite media material. A suitable magnetic separator is manufactured by Eriez Magnetics Inc. of Erie, Pennsylvania (model no. A magnetic rotor).

By recycling and regenerating most of the composite blasting media, a substantial cost savings in the amount of material which must be properly disposed of is achieved. Thus, the recyclable composite blasting media according to the present invention is beneficial to the 35 environment in general. 09:04:23 Since certain changes may be made in the above described composite media without departing from the spirit and scope of the invention herein involved, it is intended that all subject matter contained in the above 5 description and shown in the accompanying drawings shall not be construed as limiting the invention, but shall be interpreted merely as examples illustrating the inventive concept disclosed herein. 09:04:23

Claims (19)

WO 96/05021 PCT/US94KI9411 27 3 1 4 9 -11- We claim:

1. A method of recycling a used composite blasting media after being propelled through desired blasting equipment, said composite blasting media comprising a 5 plurality of granules which each contain a plurality of discrete particles of an abrasive component physically interconnected with one another by a carrier component, which is a solid at room temperature, said method comprising the steps of: 10 collecting the composite blasting media after at least one blasting cycle; nixing at least one of additional abrasive component and additional carrier component with the collected composite blasting media; and 15 forming the mixture of composite blasting media into a plurality of granules each containing a plurality of discrete particles of the abrasive component physically interconnected with one another by the carrier component.

2. A method of recycling the composite blasting 20 media of claim 1, further comprising the step of washing, in a washing device, the collected composite blasting media with a cleaning solution prior to the mixing step.

3. A method of recycling the composite blasting media of claim 2, further comprising the step of removing 25 moisture from the washed composite blasting media, with a moisture removing mechanism, prior to the mixing step.

4. A method of recycling the composite blasting media of claim 1, further comprising the step of cleaning the collected composite blasting media, with a cleaning 3 0 device, prior to the mixing step.

5. A method of recycling the composite blasting media of claim 1, further comprising the step of screening the collected composite blasting media prior to the mixing step. 09:04:23 WO 96/05021 PCT/US94/0941I 273149 -12-

6. A method of recycling the composite blasting media of claim 1, further comprising the step of using the composite blasting media a plurality of times prior to recycling the composite blasting media. 5

7. A method of recycling the composite blasting media of claim 1, wherein said mixing step comprises the step of mixing both additional abrasive component and additional carrier component with the collected composite blasting media. 10

8. A method of recycling the composite blasting media of claim 1, further comprising, after the collecting step but prior to the mixing step, the steps of: causing the collected composite blasting media to swell by allowing the collected composite blasting 15 media to absorb liquid; and screening the swelled composite blasting media with a screening device so as to allow fines and other debris and contaminates to pass through the screening device while retaining the swollen composite blasting 20 media.

9. A method of recycling the composite blasting media of claim 8, further comprising the step of removing the absorbed liquid from the composite blasting media with a liquid absorbing mechanism. 25 10. A method of recycling the composite blasting media of claim 1, wherein said forming step comprises the steps of: heating the mixture of the composite blasting media to melt the carrier component, which is a solid at 30 room temperature; allowing the heated composite blasting media to cool to a solidifying temperature of the carrier component and thereby solidify the composite blasting media; and grinding the composite blasting media into a 3 5 plurality of granules each containing a plurality of 09:04:23

WO 96/05021 PCT/US94/09411 273149 -13- discrete particles of the abrasive component physically interconnected with one another by the carrier component.

11. A method of recycling the composite blasting media of claim 10, further comprising, prior to allowing 5 the heated composite blasting media to solidify, the step of thoroughly mixing the heated composite blasting media to form a uniform mixture thereof.

12. A method of recycling the composite blasting media of claim 1, wherein said forming step comprises the 10 steps of: allowing the mixture of the composite blasting media with at least one of additional abrasive component and additional carrier component to chemically react with one another; 15 allowing the chemically reacted composite blasting media to solidify; and grinding the composite blasting media into a plurality granules each containing a plurality of discrete particles of the abrasive component physically 2 0 interconnected with one another by the carrier component.

13. A method of recycling the composite blasting media of claim 12, further comprising, prior to allowing the chemically reacted composite blasting media to solidify, the step of thoroughly mixing the mixture of the 25 composite blasting media to form a uniform mixture thereof.

14. A method of recycling the composite blasting media of claim 1, wherein said forming step comprises the steps of: 30 impregnating additional abrasive component into the carrier component; and grinding the composite blasting media into a plurality granules each containing a plurality of discrete particles of an abrasive component physically 09:04:23 WO 96/05021 PCT/US94/09411 17 3 14 9 interconnected with one another by the carrier component.

15. A method of forming a recyclable granulated composite blasting media for use in treating a surface to 5 remove undesired contaminants therefrom, said composite blasting media being suitable for being propelled via a fluid stream through desired blasting equipment; said method comprising the steps of: forming granules of the composite blasting 10 media, each said granule comprising a plurality of discrete particles of an abrasive component physically interconnected with one another by a carrier component, which is solid at room temperature, the carrier component being selected to wear, during use of the composite 15 blasting media, at a rate so as to continuously expose additional underlying abrasive particles on an exterior surface of that composite media particle, but not at a rate to allow the premature separation of the abrasive particles from an exterior surface of that composite media 2 0 particle; propelling the recyclable composite blasting media through desired blasting equipment to treated a desired surface; collecting the composite blasting media with a 25 collecting device and cleaning the collected composite blasting media, after at least one blasting cycle, with a cleaning device; and reforming the composite blasting media into a plurality of granules each containing a plurality of 30 discrete particles of an abrasive component physically interconnected with one another by a carrier component.

16. A method of recycling the composite blasting media of claim 1, further comprising the steps of separating recyclable composite blasting media, with a 09:04:23 273149 -15- separating device, from fines, debris and contaminates after the collecting step and prior to the mixing step.

17. A method of recycling a used composite blasting media after being propelled through desired blasting equipment, said composite blasting media comprising a plurality of granules which each contain a plurality of discrete particles of an abrasive component physically interconnected with one another by a carrier component, which is solid at a temperature below room temperature, said method comprising the following steps occurring at a temperature below room temperature: collecting the composite blasting media after at least one blasting cycle; mixing at least one of additional abrasive component and additional carrier component with the collected composite blasting media/ and forming the mixture of composite blasting media into a plurality of granules each containing a plurality of discrete particles of the abrasive component physically interconnected with one another by the carrier component.

18. A method of recycling a used composite blasting media substantially as herein described with reference to any one of the accompanying drawings.

19. A method of forming a recyclable granulated composite blasting media substantially as herein described with reference to any one of the accompanying drawings. INTELLECTUAL PROPERTY OFFICE OF N.Z. 16 SEP 1998 RECEIVED