Patent Application
20170008019
NA
This invention relates generally to coating or spraying and specifically to the manufacture of cylindrical items such as cans/containers and the coating of the interior of such items.
This invention was not made under contract with an agency of the US Government, nor by any agency of the US Government.
Modern coating of the interiors of objects relies upon spray gun technology. A typical spray gun has a barrel having a nozzle at the lower end and a feed mechanism at the upper end, often a body which is part of a recirculating loop of lacquer, paint and/or other coating.
Traditionally, the cans descend in a track into a rotating star wheel, which is oriented vertically. As the star wheel rotates, the cans pass in front of the spray gun, which has been adjusted for the size and shape of cans being sprayed, and the spray gun is activated by automated controls for a brief period of time (some milliseconds) during which it coats the interior of the can. The process continues during a production operation or production run (or during a shift) and coats the interiors of many hundreds of cans per minute. Various means and methods might be employed to speed up the act of spraying the can during a run, however, the present invention is not directed at that.
In most instances it is impossible to prevent a small amount of spray containing lacquer or coating (hereinafter either term is used) from failing to reach the interior surface of the can being coated. This spray may be entrained in air moving the wrong direction, it may be sprayed in the wrong direction initially or as a result of the gun falling out of alignment, it may be necessary due to the geometrical limitations of the gun or for other reasons. This “overspray” is a waste of lacquer obviously, what is more important is that it is an environmental issue of some importance.
An “environmental issue” is not necessarily limited to the modern green meaning of the term, although the overspray is a form of atmospheric pollution. What is of a more immediate concern is that the overspray is an unwelcome source of equipment fouling, jams, irregularity in output and is detrimental to worker efficiency and health. The overspray can coat all equipment in the immediate area to the point that it can be impossible to read or discern any fine details on the machinery, the buildup must be removed and the removal is normally an another source of lost production time and increased maintenance frustrations, costs, and more.
It would be preferable to provide a means of controlling the overspray in the unique conditions of can manufacture, in particular, in the technical area of interior coating of cylindrical bodies with coatings/lacquers.
The present invention teaches an overspray control and collection system. The system has a deflector portion of a hood which forces any overspray into an air channel. Air flowing through the channel under suction may carry the entrained overspray with it, through and out of the hood and into a vortex chamber which whirls the air and overspray so that they are separated by centrifugal force. A collection container may then collect the overspray while the cleaned air is allowed to exhaust.
In one embodiment, the deflector portion of the hood has a slot therethrough to allow the spray gun nozzle to protrude into the same space as the container to be coated.
In other embodiments the slot may defined two hoods, left and right, so that overspray on both sides is collected. The hoods may sit close above the open top of a container to be coated.
The hoods may then lead the overspray into air intake channels under suction (partial vacuum), so that air and entrained overspray may pass through the two conduits and exit the hood through paired exhaust vacuum ports, attached to each conduit of each hood. Exhaust pipes may then carry the air and overspray (and maintain vacuum) to a vortex chamber which is dimensioned and configured to cause the air/overspray mixture to whirl and separate. One advantageous shape may be a partial conical interior with the vacuum source set at an angle or with vanes which force airflow in the desired configuration for separation.
In another embodiment, one or more airflow control devices may be used to control the flow of air within the container being sprayed. Control of the airflow, possibly including control over turbulence versus laminarity, allows the deposit of a higher percentage of the spray onto the interior surface of the container and loss of a lower percentage into the atmosphere or otherwise not adhering to the can wall, which in turn means use of less lacquer/coating, more uniform coating, denser coating and so on.
The airflow control device may be a vacuum chamber in which the container sits while being sprayed, may be a vacuum supply such a tube which administers negative pressure, or may be an air hose which delivers timed puffs/bursts of air into the container interior (for example timed positive pressure instead of/in addition to the negative pressure). The control device may further comprise a controller to control timing of the operation of the air flow control device.
These and many other aspects, advantages, embodiments and objectives of the present invention will be understood by reference to the following.
It is therefore one aspect, advantage, objective and embodiment of the present invention, in addition to those described above, to provide an overspray collection system for use with a spray gun, the spray gun oriented to spray into the interior of a cylindrical body, the system comprising:
a left hood and a right hood, the two hoods disposed adjacent but with a gap therebetween, such spray gun on one side of the gap, such cylindrical body on the other side of such gap, such spray passing through the gap from the spray gun to the cylindrical body;
each hood having a deflector, each deflector extending at an angle to such spray, whereby such overspray may be caught upon the deflectors;
each hood further having a vacuum conduit intake defined by the hood body and the hood's deflector, the vacuum conduit intake having a negative pressure therein, whereby air and entrained overspray may be drawn into the vacuum conduit intake;
each vacuum conduit intake further having a conduit to a vacuum exhaust port from the hood, whereby the air and such entrained overspray may be exhausted from each hood.
It is therefore one aspect, advantage, objective and embodiment of the present invention, in addition to those described above, to provide an overspray collection system further comprising:
a pair of exhaust pipes, one extending from each vacuum exhaust port, whereby the air and entrained overspray may be drawn from each vacuum exhaust port.
It is therefore one aspect, advantage, objective and embodiment of the present invention, in addition to those described above, to provide an overspray collection system further comprising:
a vortex body, the vortex body having a generally circular planform, the exhaust pipes entering the vortex body, whereby the air and entrained overspray may be drawn into such vortex body.
It is therefore one aspect, advantage, objective and embodiment of the present invention, in addition to those described above, to provide an overspray collection system wherein the vortex body further comprises:
at least one vortex inducing device attached to the vortex body, the vortex inducing device dimensioned and configured to cause a vortex of the air and entrained overspray within the vortex body, whereby the air and entrained overspray are separated.
It is therefore one aspect, advantage, objective and embodiment of the present invention, in addition to those described above, to provide an overspray collection system wherein the vortex inducing device further comprises one member selected from the group consisting of: angled entrances of the exhaust pipes, an angled final exhaust, an airfoil, or combinations thereof.
It is therefore one aspect, advantage, objective and embodiment of the present invention, in addition to those described above, to provide an overspray collection system wherein the pair of hoods are symmetrical.
It is therefore one aspect, advantage, objective and embodiment of the present invention, in addition to those described above, to provide an overspray collection system each hood further comprising:
at least one mounting device whereby each hood may be attached to a spray machine, the spray machine being attached to such spray gun.
It is therefore one aspect, advantage, objective and embodiment of the present invention, in addition to those described above, to provide an overspray collection system wherein the at least one mounting device comprises: a hole dimensioned and configured to receive a fastener.
It is therefore one aspect, advantage, objective and embodiment of the present invention, in addition to those described above, to provide an overspray collection system further comprising: a first air flow control device, the first air flow control device operative to control a flow of ambient air within such cylindrical body, thereby altering flow of such spray after such spray exits such spray gun, especially within such cylindrical body.
It is therefore one aspect, advantage, objective and embodiment of the present invention, in addition to those described above, to provide an overspray collection system for use with a spray gun, the spray gun oriented to spray into the interior of a cylindrical body, the system comprising:
a conduit disposed to receive such overspray at a first end;
the conduit having a negative pressure therein, whereby ambient air and such overspray may be sucked into the conduit;
the conduit having a second end entering a vortex chamber, whereby the ambient air and such overspray may be sucked into the vortex chamber;
the vortex chamber having a spin inducer causing the air and such overspray to whirl inside of the vortex chamber, whereby such overspray may separate from the ambient air;
a final exhaust at which the air may exit the vortex chamber.
It is therefore one aspect, advantage, objective and embodiment of the present invention, in addition to those described above, to provide an overspray collection system wherein the vortex inducer further comprises one member selected from the group consisting of: angled entrances of the exhaust pipes, an angled final exhaust, an airfoil, or combinations thereof.
It is therefore one aspect, advantage, objective and embodiment of the present invention, in addition to those described above, to provide an overspray collection system further comprising:
at least one exhaust pipe, the exhaust pipe connecting to an exhaust port through which the ambient air and entrained overspray may be drawn from each vacuum exhaust port.
It is therefore one more aspect, advantage, objective and embodiment of the present invention, in addition to those described above, to provide a overspray collection system further comprising:
at least one hood, the hood disposed adjacent to a gap, such spray gun on one side of the gap, such cylindrical body on the other side of such gap, such spray passing through the gap from the spray gun to the cylindrical body;
the hood having a deflector, the deflector extending at an angle to such spray, whereby such overspray may be caught upon the deflector;
the hood further having a vacuum conduit intake defined by the hood body and the deflector, the vacuum conduit intake having a negative pressure therein, whereby air and entrained overspray may be drawn into the vacuum conduit intake;
the vacuum conduit intake further having a conduit to the vacuum exhaust port from the hood, whereby the air and such entrained overspray may be exhausted from the hood.
It is therefore one more aspect, advantage, objective and embodiment of the present invention, in addition to those described above, to provide a spray control and overspray collection system for use with a spray gun, the spray gun oriented to spray into the interior of a cylindrical body, the system comprising:
a first air flow control device, the first air flow control device operative to control a flow of ambient air within such cylindrical body, thereby altering flow of such spray after such spray exits such spray gun, especially within such cylindrical body.
It is therefore one more aspect, advantage, objective and embodiment of the present invention, in addition to those described above, to provide a spray control and overspray collection system for use with a spray gun, the spray gun oriented to spray into the interior of a cylindrical body, the system comprising:
a first air flow control device, the first air flow control device operative to control a flow of ambient air within such cylindrical body, thereby altering flow of such spray after such spray exits such spray gun, especially within such cylindrical body.
It is therefore one more aspect, advantage, objective and embodiment of the present invention, in addition to those described above, to provide a spray control and overspray collection system for use with a spray gun, the spray gun oriented to spray into the interior of a cylindrical body, wherein such first air flow control device is one member selected from the group consisting of: an air hose oriented, dimensioned and configured to provide a timed burst of ambient air into such cylindrical body; a vacuum supply oriented dimensioned and configured to provide a negative pressure to ambient air within such cylindrical body; a vacuum chamber enclosing such cylindrical body, and combinations thereof.
It is therefore one more aspect, advantage, objective and embodiment of the present invention, in addition to those described above, to provide a spray control and overspray collection system for use with a spray gun, the spray gun oriented to spray into the interior of a cylindrical body, wherein such first air flow control device further comprises: a controller operative to control operation of the first air flow control device in the time domain.
It is therefore one more aspect, advantage, objective and embodiment of the present invention, in addition to those described above, to provide a spray control and overspray collection system for use with a spray gun, the spray gun oriented to spray into the interior of a cylindrical body, wherein the first air flow control device is further operative to alter the degree of turbulence of the airflow within such cylindrical body, whereby such spray is applied to an interior surface of such cylindrical body in a denser and more uniform application of the coating.
It is therefore one more aspect, advantage, objective and embodiment of the present invention, in addition to those described above, to provide a spray control and overspray collection system for use with a spray gun, the spray gun oriented to spray into the interior of a cylindrical body, wherein the first air flow control device is further operative to alter the degree of laminar airflow within such cylindrical body, whereby an increased percentage of such spray is applied to an interior surface of such cylindrical body when compared to spray without use of the first air flow control device.
It is therefore one more aspect, advantage, objective and embodiment of the present invention, in addition to those described above, to provide a spray control and overspray collection system for use with a spray gun, the spray gun oriented to spray into the interior of a cylindrical body, further comprising:
a left hood and a right hood, the two hoods disposed adjacent but with a gap therebetween, such spray gun on one side of the gap, such cylindrical body on the other side of such gap, such spray passing through the gap from the spray gun to the cylindrical body;
each hood having a deflector, each deflector extending at an angle to such spray, whereby such overspray may be caught upon the deflectors;
each hood further having a vacuum conduit intake defined by the hood body and the hood's deflector, the vacuum conduit intake having a negative pressure therein, whereby such airflow exiting such cylindrical body and entrained overspray may be drawn into the vacuum conduit intake;
each vacuum conduit intake further having a conduit to a vacuum exhaust port from the hood, whereby the air and such entrained overspray may be exhausted from each hood.
Glossary
As used herein a spray gun may be any commercially available or used device which sprays very fine droplets/particles of lacquer, coating, paint or the like used to coat part or all of a cylindrical item of manufacture, including a container such as a can. This is the pressures part of a spray machine.
A spray gun barrel is the part which actually ejects paint, lacquer or coating into the nozzle. It may be largely cylindrical with numerous features such as extensions, indents, additions and so on, most particularly including a feed-body near the rear end, the feed body being the structure which accepts liquid spray material into the cylindrical body from a feed system.
The feed source may be a recirculating loop containing the material or may be a one way feed line (recirculation being quite common in can coating processes).
The spray gun barrel will have a nozzle and/or nozzle end, usually the end closest to the cylindrical item of manufacture, which reduces the liquid flowing inside the barrel to a fine spray of droplets/particles of the liquid. This nozzle end must have a clear field of fire to the item of manufacture, unblocked by any equipment which would prevent uniform coating of the container/product.
As used herein a cylindrical item of manufacture may refer to any object, particularly including packaging for consumer goods, having a shape which is a generally cylindrical body with an end which is open at least briefly during manufacture, and which requires such a coating or lacquer or paint on the inside/interior surface. Examples include aluminum and steel cans (for beverages or food) but this term includes any item, regardless of material, which may be coated internally. Aluminum cans are well known for requiring coating merely to hold more customary types of beer, food, soft drinks, juice and other liquids.
Overspray refers to the excess spray, mis-aimed spray or other spray which the nozzle of the spray gun ejects but which ends up not on the appropriate surface for coating. Most generally, this overspray will be present in the ambient air of the pocket of the star wheel, at least for a short period of time.
Inlets, conduits, ports, and so on have their ordinary meanings.
A vortex/cyclone as used herein refers to a body having a hollow interior, the hollow interior being dimensioned and configured to cause the rapid rotation of air passing through. Such vortices may be generally cylindrical, but may also be conical, frusta-conical and so on. The arrangement of the source of vacuum and the source of air may be enough, combined with the geometry of the vortex, to cause the rotation/whirl of the air, however, vanes or propelling devices may be used in the vortex as well.
It will be understood that the vortex will be of sufficient efficiency to cause a separation of the overspray from the air carrying it. This will generally be termed “centrifugal” (centripetal, “centrifical”) but within the scope of the term as used herein may well simply be caused by the whirling air forcing the overspray, which may be quite sticky, to contact objects such as side walls, screens, filters and so on.
Vacuum in this application does not refer to a vacuum particularly close to perfect, the vacuum may be quite modest as long as it produces the desired suction of the air into the conduits and the vortex. The vacuum (negative pressure) may by itself be sufficient to produce the whirling of the air in the vortex. Vacuum in this case may within the scope of the invention be generated by a “vacuum” (the device) but the term is not so intended herein.
Glossary End
Spray gun 100 has a nozzle pointing downward, spray 104, including some which will not reach the target surface, may be seen moving downward in the figure. The nozzle extends to gap 102. The nozzle may be quite close to the gap 102 on either side, and need not be exactly centered in the gap, though that may be preferable.
Hood 106 may be seen in partial cross section and it will be appreciated that there are actually two hoods or vacuum chambers present, one on either side of the nozzle and gap 102. The vacuum conduit intake 108 and deflector 110 are thus matched by similar or identical intakes and deflectors on the other side, however, these are not visible due to the other side of the hood being shown without cross section.
It will be understood that any spray which begins to follow a curved trajectory upward to escape the cup-like shape of the item of manufacture/container/can will either impact the deflector 110 or will more likely be sucked into the vacuum conduit intake 108: the deflector 110 acts not only to physically block some overspray but more importantly it acts to direct airflow in the desired direction: into the intake 108.
Hood 400 has vacuum inlet/conduit 402 leading to the conduit 406, which in turn leads to the exhaust port. Overspray/air flow 404/408 flows through the conduit inlet 402 and the conduit to exhaust port 406.
Mounting hole 410 may be seen as well, part of another possible pattern of mounting holes. Various arrangements for mounting in alternative to holes may be used within the scope of the invention.
Hood 500 has the same inlet area, vacuum conduit 502 into which air & overspray flow 504 may pass, after which the vacuum will cause it to enter the conduit to exhaust 506, shown by air/overspray flow arrow 508.
Star wheel 602 (having only 4 pockets, most have more than 4 pockets) is arrayed vertically, with spray gun 604 shown in simplified form firing into a container in one pocket. Hood 606 is depicted as a single hood which covers only half of the pocket: this is for clarity, in most preferred embodiments the entire spray and pocket will be covered and thus invisible.
Vortex chamber 608 may be seen below the hood 606.
In use, overspray flow from can to hood 610 will swirl to a limited degree, but will actually be contained within the hood, this is the purpose of the hood. The hood 606 may in fact fit so closely to the item of manufacture that it largely or wholly obscures/covers the open end of the cylinder, or it may in fact seal thereto in yet further alternative embodiments, or it may be fairly “loose” and further away with a gap therebetween. The invention is not limited to the distance from the hood to the container open end.
Overspray flow from hood 606 to vortex chamber 608 is shown by arrow 612, and exhaust air by arrow 614. This very general structure to the invention is thus laid out with the key components shown.
Spray gun 800 projects into the gap between hood deflector (left) 802 and hood deflector (right) 804. The star wheel and cylindrical item of manufacture are not shown in
Spin inducer 810 and spin inducer 812 may be simple vanes which deflect the entering air/overspray into a rotational motion. Note that these vanes may also serve as collectors of overspray which impacts them, which in some embodiments may be desirable and in other embodiments may be undesirable, all within the scope of the invention.
Chamber interior 814 exhausts via exhaust 816.
Star wheel 902 rotates as shown by arrow 904, partially underneath (within, obscured by, covered by,) hood 906. With the spray guns dismounted as shown, the two gaps and in fact four different hood airflows necessary to cover two pockets of the 6 pocket star wheel may be seen. The underside of the gaps will of course be the inlet air conduits shown previously. Air from the hood 906 will enter vortex 908 under suction, be separated, and air flow 910 may exhaust while debris (overspray) flow 912 may fall, drip or otherwise enter the collection bin 914. By having a separate collection bin 914, the machine may more easily be cleaned, overspray disposed of and so on. The collection bin 914 is depicted as a cylindrical body but may be any convenient shape within the scope of the invention.
Backscatter block/hood 1002 blocks almost all view of the cans as they are sprayed, leaving only a small gap for spray gun 1004. In this two gun embodiment, one gun has been dismounted for clarity.
Vent opening (slant portion) 1204 is the deflector which guides air and blocks overspray in the desired manner discussed previously.
A certain percentage of spray 1406 will impact the interior surface of the container and become part of the coating. However, a percentage of the spray 1406 will in fact swirl with the ambient air and be lost to the atmosphere, or become overspray, etc. Thus, one advantage of the present invention is to control an airflow within the container, whereby the percentage of applied spray may be increased in comparison to a spray without control of the ambient airflow. This may or may not particularly involve control over degree of turbulence or degree of laminar air flow, but in either case the result will be decreased use of coating, increased density of coating, and more uniform coating.
Air hose 1402 may thus be pointed into the cylindrical body to deliver timed (or continuous) bursts of air to control/alter airflow within the body.
Note that these methods are not mutually exclusive and in embodiments may be used together.
Throughout this application, various publications, patents, and/or patent applications are referenced in order to more fully describe the state of the art to which this invention pertains. The disclosures of these publications, patents, and/or patent applications are herein incorporated by reference in their entireties, and for the subject matter for which they are specifically referenced in the same or a prior sentence, to the same extent as if each independent publication, patent, and/or patent application was specifically and individually indicated to be incorporated by reference.
Methods and components are described herein. However, methods and components similar or equivalent to those described herein can be also used to obtain variations of the present invention. The materials, articles, components, methods, and examples are illustrative only and not intended to be limiting.
Although only a few embodiments have been disclosed in detail above, other embodiments are possible and the inventors intend these to be encompassed within this specification. The specification describes specific examples to accomplish a more general goal that may be accomplished in another way. This disclosure is intended to be exemplary, and the claims are intended to cover any modification or alternative which might be predictable to a person having ordinary skill in the art.
Having illustrated and described the principles of the invention in exemplary embodiments, it should be apparent to those skilled in the art that the described examples are illustrative embodiments and can be modified in arrangement and detail without departing from such principles. Techniques from any of the examples can be incorporated into one or more of any of the other examples. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.
