Coating dryer system

• US 6,256,903 B1
• Filed: 03/09/1999
• Issued: 07/10/2001
• Est. Priority Date: 08/23/1996
• Status: Expired due to Fees

• Current Assignee: Research Incorporated
• Original Assignee: Research Incorporated
• Inventors: Rudd, Paul D.
• Primary Examiner(s): GRAVINI, STEPHEN MICHAEL
• Application Number:
  US09/265,711
• Time in Patent Office: 854 Days
• Field of Search: 345/28, 345/35, 345/40, 345/43, 345/46, 345/49, 345/80, 34/61, 34/71, 34/92, 341/23, 346/05, 346/21, 346/26, 346/37, 341/87, 341/86, 342/10, 342/19, 343/80, 343/81, 344/12, 344/42, 345/00, 342/02, 341/17, 341/18, 341/19, 341/20
• US Class Current: 34/412
• CPC Class Codes: F26B 13/14 Rollers, drums, cylinderssorbent surfaces F26B13/26; Arrangement of drives, supports, bearings, cleaning
• CPC Class Codes: F26B 13/145 on the non-perforated outside surface of which the material is being dried by convection or radiation
• CPC Class Codes: F26B 13/18 heated or cooled, e.g. from inside, the material being dried on the outside surface by conduction

Abstract

The present invention relates to heating systems for drying wet coatings such as printing inks, paint, sealants, etc. applied to a substrate. In particular, the invention relates to a drying system in which a blower having an inlet directs a current of heated gas such as air towards a wet coating on a substrate to dry the coating and wherein the heated air is circulated back to the inlet of the blower once the air impinges the coating on the substrate. The present invention also relates to a drying system in which the substrate is supported about a thermally conductive roll having a plurality of energy emitters disposed within the conductive roll along a length of the conductive roll. The plurality of energy emitters are controlled to selectively emit energy along the length of the conductive roll. The dryer system preferably includes means for sensing temperatures of the roll along the length of the conductive roll, wherein the energy emitted by the energy emitters along the length of the roll varies based upon the sensed temperatures along the length of the roll.

Claims

1. A dryer system for drying a coating applied to a substrate, the dryer system comprising:

a substrate support supporting the substrate, wherein the substrate support includes a roll having a length and a peripheral surface for supporting the substrate;

a plurality of energy emitters disposed within the roll along the length of the roll;

means for controlling the plurality of energy emitters to selectively emit energy along the length of the roll;

means for impinging the substrate on the roll with heated air; and

means for creating a partial vacuum adjacent the substrate to withdraw the heated air away from the substrate once the heated air has impinged the substrate.

2. The dryer system of claim 1 wherein the means for impinging the substrate has an inlet and wherein the dryer system includes means for circulating the withdrawn heated air to the inlet.

3. The dryer system of claim 1 wherein the means for creating a partial vacuum includes:

a vacuum chamber having at least one inlet adjacent the substrate; and

means for withdrawing air from the vacuum chamber.

4. The dryer system of claim 3 wherein the means for withdrawing air from the vacuum chamber comprises a blower.

5. The dryer system of claim 3 wherein the vacuum chamber includes a plurality of inlets arcuately surrounding at least a portion of the roll.

6. The dryer system of claim 1 wherein the means for impinging includes:

a pressure chamber adjacent the substrate, the chamber defining the inlet and including at least one outlet directed at the substrate;

means for heating air within the pressure chamber; and

means for pressurizing air within the pressure chamber.

7. The dryer system of claim 6 wherein the means for heating comprises a heater.

8. The dryer system of claim 6 wherein the means for pressurizing comprises a blower.

9. The dryer system of claim 6 wherein the pressure chamber includes a plurality of outlets arcuately surrounding at least a portion of the roll.

10. The dryer system of claim 1 wherein the plurality of energy emitters includes a plurality of band heaters.

11. The dryer system of claim 1 wherein the means for controlling the plurality of energy emitters includes:

a plurality of spaced temperature sensors for sensing temperatures along the length of the roll, wherein the energy emitters are controlled based upon sensed temperatures.

12. The dryer system of claim 1 wherein the means for impinging includes:

a first convection unit arcuately surrounding a first arcuate portion of the roll for impinging the first arcuate portion of the roll with heated air;

a second convection unit arcuately surrounding a second arcuate portion of the roll for impinging the second arcuate portion of the roll with heated air; and

means for selectively controlling the first and second convection units.

13. The dryer system of claim 1 including:

an exhaust for removing air from the dryer system to control relative humidity.

14. A method for drying a wet coating applied to a moving web, the method comprising:

supporting the moving web on a rotating roll;

substantially enclosing the moving web and roll;

heating a gas to an elevated temperature;

pressurizing the hot gas and directing the pressurized hot gas towards the moving web on the roll; and

creating a partial vacuum adjacent the moving web so as to withdraw the gas once the gas impinges upon the moving web.

15. The method of claim 14 including:

recirculating the withdrawn gas for reheating, repressurization and redirection towards the moving web on the roll.

16. The method of claim 14 including:

emitting energy through the roll for absorption by the moving web.

17. A dryer system for drying a coating applied to a moving web, the dryer system comprising:

a rotating roll for supporting the moving web;

air outlets spaced circumferentially about the roll for impinging the moving web thereon with heated air; and

air inlets spaced circumferentially about the roll for creating a partial vacuum adjacent the moving web on the roll once the heated air has impinged the moving web.

18. The dryer system of claim 17, and further comprising:

an air recirculation system connecting the air outlets and air inlets.

19. The dryer system of claim 17, and further comprising:

an energy emitter within the roll for applying energy to the moving web as it traverses the roll.

20. The dryer system of claim 17, and further comprising:

a plurality of energy emitters within the roll for applying energy to the moving web as it traverses the roll.

21. The dryer system of claim 20, wherein the energy emitters are disposed along the length of the roll, and further comprising:

a control apparatus for selectively determining the amount of energy applied by each energy emitter.

22. The dryer system of claim 21 wherein the control apparatus comprises:

a plurality of temperature sensors spaced along the length of the roll, whereby the amount of energy applied by each of the energy emitters is controlled based upon a temperature sensed by a respective one of the temperature sensors.

23. A dryer system for drying a coating applied to a moving web, the dryer system comprising:

a rotating roll for supporting the moving web;

means for impinging the moving web with heated air; and

means for creating a partial vacuum adjacent the moving web on the roll to withdraw the heated air away from the moving web once the heated air has impinged the moving web.