Claims
- 1. A method of applying a coating to a moving object including the steps of:
- passing said object through an enclosed coating space,
- applying a liquified solvent-free coating material, which is normally solid at ambient temperature, from applicators within said space to a surface of said object;
- maintaining the temperature of said object such that at least a portion of said applied liquified coating material partially solidifies upon contact with the surface of said object;
- maintaining an excess portion of applied coating material not solidifying on the object surface in liquified form for recovery, and
- heating said partially solidified coating material on said object with a non-contact heater, after its passage through said coating space and liquifying said coating material so that the material flows and forms a continuous coating on said object.
- 2. A method as in claim 1 including the steps of:
- recovering said excess portion of liquified coating material in a liquified state in said coating space; and
- recirculating said recovered coating material to one or more of said applicators for application to other object surfaces within said coating space.
- 3. A method as in claim 2 wherein said coating space is defined by housing walls and further including the step of heating said housing walls to maintain oversprayed coating collecting on said walls in a liquified state.
- 4. A method as in claim 3 wherein the step of heating said housing walls includes the step of passing heated fluid through said walls.
- 5. A method as in claim 2 wherein said recirculating step includes collecting liquified excess coating material in a heated sump.
- 6. A method as in claim 5 wherein said recirculating step further includes pumping liquified coating material from said heated sump to one or more of said applicators.
- 7. A method as in claim 6 including sensing the level of liquified coating material in said heated sump and adding additional liquified coating material into said sump when said level decreases below a predetermined minimum.
- 8. A method as in claim 1 wherein said coating material is sprayed onto said object through nozzles and further including the step of heating said nozzles.
- 9. A method as in claim 1 further including the step of heating said object to warm a surface of said object prior to said coating material applying step, the coating material at least partially solidifying on said warmed object surface.
- 10. A method as in claim 1 including the step of supplying said liquified coating material to said coating space for coating an object from at least two separate coating material supplies and through a switch-over means such that one supply is used while the other is not used.
- 11. A method as in claim 1 wherein said object is an elongated object.
- 12. A method as in claim 1 including the step of abrading the object before applying the coating material to provide improved adherence of the coating material to the object.
- 13. A method as in claim 1 including the step of conveying the object after the coating material is applied on conveyors cooled below the liquification temperature of the coating material to prevent the conveyors from damaging the smooth continuous coating.
- 14. A method of applying solvent-free coating material which is solid at room temperature to an object, comprising the steps of:
- heating said coating material to a liquified state;
- supplying said coating material to at least one applicator while the coating material is still in said liquified state;
- applying said coating material in a liquified state to said object within an enclosed coating space by spraying the object with said applicator;
- maintaining said coating material and overspray coating material from the spraying in a liquified state during said application and maintaining the temperature of said object such that material contacting said object at least partially solidifies upon contact with the surface of said object; and
- thereafter heating the coated surface of said object with generally non-contact heat to liquify said at least partially solidified coating material and to cause said material to flow together in a continuous coating on the object surface.
- 15. The method of claim 14 further including the steps of preheating said object to warm the exterior surface of said object prior to the application of said coating material, the coating material at least partially solidifying on said warmed object surface.
- 16. A method of applying a coating to an object, comprising the steps of:
- passing an object through a coating space;
- applying a liquified solvent-free coating material, which is normally solid at ambient temperature, to a surface of said object within said coating space by means of one or more applicators disposed within said space;
- maintaining the temperature of said object such that at least a portion of said applied liquified material partially solidifies upon contact with said object surface while said material prior to said contact remains liquid;
- maintaining an excess portion of the liquified coating material, not solidifying on the object surface, in liquified form within said coating space; and
- recirculating said maintained excess portion of coating material in liquified form to said one or more applicators for application to other objects or object surfaces within said coating space;
- heating said partially solidified coating material on said object surface with a non-contact heater after its passage through said coating space and liquifying said coating material so that the material flows and forms a continuous coating on said object surface.
- 17. A method of applying a coating to a moving object including the steps of:
- passing said object through an enclosed coating space,
- applying a liquified solvent-free coating material, which is normally solid at ambient temperature, from applicators within said space to a surface of said object, such that at least a portion of said liquified material partially solidifies upon contact with the surface of said object while excess coating material not solidifying on the object surface is maintained in liquified form for recovery,
- heating said partially solidified coating material on said object after its passage through said coating space to cause said coating material to flow and form a coating on said object; and,
- abrading the object before applying the coating material to provide improved adherence of the coating material to the object.
- 18. Apparatus for applying solvent-free coating material which is solid at room temperature to a moving non-textile object, comprising:
- a heater for heating the solvent-free coating material to a liquified state;
- a housing having an inlet, an outlet and walls defining a coating space therein for receiving a portion of said object passing therethrough between the inlet and outlet;
- at least one coating applicator within said coating space for spraying liquified solvent-free coating material onto said portion of the object passing through said coating space;
- said housing maintaining the sprayed portion of said object at a temperature such that sprayed coating material partially solidifies on said object portion;
- a liquid delivery system for transporting the liquified coating material to said coating applicator located within said housing;
- a liquifying system for maintaining oversprayed coating material in a liquid state within said housing;
- a reclamation system for returning said oversprayed liquified coating material to said coating applicator; and
- a post-spray heater positioned proximate the outlet, the post-spray heater spaced from the object and operable for heating said sprayed portion and the partially solidified sprayed coating and causing said coating material to flow together in a continuous coating on the object.
- 19. The apparatus of claim 19 wherein said liquifying system further includes a heating system for heating said walls for maintaining the oversprayed coating material in a liquid state.
- 20. The apparatus of claim 14 wherein said housing walls are comprised of inner and outer wall elements having spaces therebetween and further including a circulating system to circulate a heated material through said spaces to heat the walls.
- 21. The apparatus of claim 18 wherein said reclamation system comprises a sump located in the lower portion of said housing below said coating space and a pump operatively connected to said sump for returning coating material to said applicator.
- 22. The apparatus of claim 21 wherein said sump includes a sump heater to control the temperature of said coating material in said sump.
- 23. The apparatus of claim 22 wherein said sump heater comprises a heated platen underlying said sump.
- 24. The apparatus of claim 21 wherein said heater for heating coating material to a liquid state includes a supply for supplying liquified coating material to said sump.
- 25. The apparatus of claim 24 including a level control within said sump for controlling said supply to selectively supply liquified coating material to the sump.
- 26. The apparatus of claim 18 wherein said coating applicator is a heated spray gun.
- 27. The apparatus of claim 18 wherein said post-spray heater comprises one or more flame burners disposed for directing flames toward said object.
- 28. The apparatus of claim 18 further including a pre-spray heater disposed outside said inlet for preheating said object to warm the exterior surface of said object prior to the spraying of any coating material thereon while maintaining said object at a temperature for partially solidifying said coating material sprayed thereon.
- 29. The apparatus of claim 18 wherein said coating applicator is a spray nozzle.
- 30. The apparatus of claim 18 including at least two separate heaters and supplies for heating said coating material to a liquid state and for supplying said liquified coating material to said coating applicator and further including a switch-over between said supplies so that one of said supplies can be used to supply said coating applicator while the other of said supplies is not being used.
- 31. The apparatus of claim 18 further comprising a conveyor system with conveying elements to contact the object and convey the object after it has been coated, at least one of the conveying elements cooled to a temperature below the liquifying temperature of the coating material to prevent adhesion of the sprayed coatings material to the element.
- 32. The apparatus of claim 31 wherein the conveying element has a cooling space defined therein and further including a coolant circulation system for circulating a coolant fluid through the cooling space of the element to cool the element.
- 33. The apparatus of claims 32 wherein the elements are rollers on which the object rolls after it has been sprayed.
- 34. The apparatus of claim 31 wherein the temperature of the elements is in the range of approximately 35.degree. F. to 55.degree. F.
- 35. The apparatus of claim 18 further comprising an abrading device for abrading an outer surface of the object before it is sprayed with liquified solvent-free coating material to promote improved adhesion of the sprayed material to the surface.
- 36. The apparatus of claim 35 wherein the abrading device includes at least one abrading element and a drive mechanism to move the abrading element against the object and abrade the surface of the object.
- 37. The apparatus of claim 36 wherein the abrading device includes another abrading element positioned generally opposite the one abrading element to abrade opposite surfaces of the object.
- 38. The apparatus of claim 37 wherein the abrading elements are moved in opposite directions against the object to offset one another and reduce the motion of the object abraded by the abrading elements.
- 39. The apparatus of claim 36 wherein the abrading element is a circular brush which is rotated by the drive mechanism to abrade the object.
- 40. The apparatus claim 36 wherein the abrading element is adjustably mounted to be selectively positioned with respect to said object to abrade a selected surface of the object.
- 41. The apparatus of claim 18 wherein said post-spray heater provides non-conductive heat to said sprayed coating material for flowing said coating material into a continuous coating.
- 42. Apparatus for applying solvent-free coating material, which is solid at ambient temperature, to a moving non-textile object, comprising:
- a housing defining an enclosed coating space through which said object passes and is therein coated;
- a heater for heating the solvent-free coating material to a liquified state;
- an applicator inside said coating space for applying said liquified coating material onto a surface of said object within said coating space wherein a portion of said liquified coating material partially solidifies upon contact with the surface of said object;
- a liquifying system for maintaining excess applied coating material in said housing in a liquified state except for that partially solidified coating material applied on said object surface,
- wherein said coating material remains liquid until contacting the surface of said object, and excess applied coating material is maintained in a liquified state for recovery; and
- a post-application heater disposed outside said coating space and spaced from said object for applying external heat to said partially solidified coating material on said object surface for flowing said coating material into a continuous coating on said object surface.
- 43. Apparatus as in claim 42 further including a liquid delivery system for supplying liquified coating material to said applicator and for maintaining said coating material in a liquified state prior to application to said object.
- 44. Apparatus as in claim 43 wherein said liquid delivery system includes a heated sump and a pump for pumping liquified coating material from said sump to said applicator.
- 45. Apparatus as in claim 44 further including a supply for supplying liquified coating material to said sump, and a coating material level sensor in said sump for controlling said supply for said sump.
- 46. Apparatus as in claim 43 wherein said liquid delivery system comprises a heated, double acting piston pump.
- 47. Apparatus as in claim 42 wherein said applicator comprises at least one spray nozzle for spraying liquified coating material onto said object.
- 48. Apparatus as in claim 42, wherein said housing comprises a plurality of walls, and the liquifying system includes a heating systems for heating said walls to maintain excess applied coating material in a liquified form.
- 49. Apparatus as in claim 48 wherein said walls are insulated and have spaces adjacent said insulation, said heating system further including an apparatus for pumping heated fluid through said spaces for heating the walls.
- 50. Apparatus as in claim 42 wherein said applicator comprises at least one bank of coating material spray nozzles disposed about said coating space and staggered with respect to one another for spraying coating material onto said object.
- 51. Apparatus as in claim 42 wherein said applicator comprises at least two independent and semi-circularly arranged banks of coating material spray nozzles for spraying coating material onto said object, each bank mounted on a semi-circular support, and wherein nozzles of one bank are staggered with respect to nozzles of another bank.
- 52. Apparatus as in claim 51 wherein said semi-circular supports are movably mounted for selective movement away from and outside said coating space.
- 53. Apparatus as in claim 42 wherein said applicator comprises a semi-circular bank of coating material spray nozzles mounted on a semi-circular structure wherein the nozzles are staggered with respect to each other.
- 54. Apparatus as in claim 53 wherein said semi-circular structure is slidably mounted on a guide to be selectively slid outside said coating space.
- 55. Apparatus as in claim 42 wherein said post-application heater for heating said partially solidified coating material on said object surface is disposed outside said coating space.
- 56. Apparatus as in claim 42 further including a pre-application heater for externally preheating said object to warm the surface of said object upstream of said coating space prior to the application of any coating material to said object surface while maintaining said object at a temperature for partially solidifying said coating material applied thereon.
- 57. Apparatus as in claim 42 wherein said post-application heater provides generally non-conductive heat to said partially solidified coating material for flowing said coating material into a continuous coating.
- 58. Apparatus for applying a non volatile, solvent-free coating material, which is solid at ambient temperature, to an elongated moving tubular shaped object and comprising:
- a. a housing defining a coating space having an inlet and outlet thereto, for passage therethrough of said elongated object for coating;
- b. coating material spray nozzles disposed within and about said coating space, for spraying said coating material in liquified form onto a portion of said elongated object as it passes through said coating space with said coating material partially solidifying upon application to said object portion in said coating space;
- c. a heated supply system for heating said coating material to a liquified state and for supplying liquified coating material to said nozzles said supply system including:
- i. a heated sump for receiving liquified coating material from a supply of coating material,
- ii. a valve for controlling flow of liquified coating material from said supply into said heated sump;
- iii. a coating material level detector in said sump for controlling said valve and said flow of liquified coating material from said supply into said sump;
- iv. a heated pump for pumping liquified coating material from said sump to said nozzles; and
- v. heated hoses for conveying liquified coating material from said pump to said nozzles;
- d. a heating system coupled to the housing for heating interior walls of said housing defining said coating space to maintain oversprayed coating material, which does not partially solidify on said object portion, in liquified form;
- e. a post-spray heater downstream of said coating space and surrounding said tubular shaped objects emerging from said housing outlet, said post-spray heater spaced from the object and externally heating said partially solidified coating material on said object portion to cause said coating material to flow out on said object to provide a continuous coating thereon while the temperature of said elongated object is not significantly raised; and
- f. said sump operatively disposed with respect to said coating space for receiving oversprayed liquified coating material therefrom for recirculation to said spray nozzles.
- 59. Apparatus for applying a solvent-free coating material to an elongated object comprising:
- a housing having an inlet and an outlet and walls defining a coating space;
- a sump;
- a heating system for heating said housing walls such that coating material engaging said walls is liquified and flows down said walls toward said sump;
- a spraying device for spraying liquified coating material onto a portion of said object in said coating space as said object portion passes therethrough, the liquified coating material engaging said object portion and partially solidifying on a surface of said object portion within said coating space; and
- a heater device downstream of said outlet encircling a coated object portion emerging from said outlet and spaced from said coated object portion, the heater device operable for heating said coating material as the coated objected passes thereby to liquify said partially solidified material on said object portion for coating said object portion with a continuous coating of material.
- 60. Apparatus as in claim 59 wherein said heater device downstream of said outlet, comprises a series of gas burners disposed in a circle about said object portion for heating said object without physical contact therewith.
- 61. Apparatus as in claim 59 wherein said wall heating system is also operable for maintaining all coating material in said coating space in a liquified state except for the partially solidified coating material on said object portion in said coating space.
Parent Case Info
This application is a continuation-in-part of U.S. application Ser. No. 07/705,516 filed May 24, 1991, now abandoned, and entitled "Apparatus and Methods for Applying Solvent-Free Liquified Coatings to Object in a Reclaim Space".
US Referenced Citations (24)
Foreign Referenced Citations (3)
Number |
Date |
Country |
555124 |
Apr 1958 |
CAX |
4125430 |
Mar 1992 |
DEX |
1328151 |
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GBX |
Non-Patent Literature Citations (3)
Entry |
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Patent Abstracts of Japan, "Abstract No. 92304476.2" vol. 3, No. 75 (no date). |
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Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
705516 |
May 1991 |
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