Claims
- 1. A method for transferring a moving web from a first location to a rotating roll in a web processing machine comprising:stabilizing the moving web on an airfoil located between the first location and a roll foil; directing the moving web toward the roll foil, the roll foil having an internal volume, a back surface, and a gap in the back surface in fluid communication with the internal volume connected to a source of vacuum; the placement of the roll foil defining a region bounded by the rotating roll on a first side, the back surface on a second side, and the web on a third side; and extracting from the region into the internal volume of the roll foil by vacuum through the gap at least a portion of the boundary layer air traveling with the rotating roll.
- 2. The method of claim 1 wherein the roll foil has a planer top surface, and the airfoil directs the moving web to run adjacent to the top surface stabilizing the moving web on the roll foil prior to being transferred to the rotating roll.
- 3. The method of claim 2 wherein the roll foil has a deflector protruding partially into the moving web attached to the roll foil where the top surface meets a front surface, and the deflector reduces the amount of boundary layer air between the moving web and the top surface.
- 4. The method of claim 1 wherein a boundary layer reduction member is attached to the back surface defining a fourth side of the region, and the boundary layer reduction member reduces the amount of boundary layer air traveling with the rotating roll.
- 5. The method of claim 4 wherein the boundary layer reduction member comprises a wiper either touching the rotating roll or in close proximity to the rotating roll.
- 6. The method of claim 4 wherein the boundary reduction member comprises an air shower blowing against the rotating roll in a direction opposing the rotation.
- 7. The method of claim 6 wherein the air shower is a drilled pipe.
- 8. The method of claim 6 wherein the air shower is a coanda effect nozzle.
- 9. The method of claim 1 wherein the roll foil has at least one opening located in a front surface in fluid communication with the internal volume, and at least a portion of the boundary layer of air traveling with the moving web is extracted through the opening.
- 10. The method of claim 9 wherein at least a portion of the opening is located within the thickness of the boundary layer of air traveling with the moving web.
- 11. The method of claim 9 wherein the airflows entering the gap and the opening can be adjusted by a movable plate that changes the size of the opening.
- 12. The method of claim 1 wherein the region is at a pressure less than atmospheric pressure.
- 13. The method of claim 1 wherein the airfoil has a bottom, a top, a nose, and a tail; the bottom being essentially flat, the nose being a curved surface attached to the bottom and the top, the top being another curved surface extending from the nose to the tail meeting with the bottom at an edge.
- 14. The method of claim 1 wherein two or more airfoils are placed between the first location and the roll foil above the web, and the airfoils intermittently stabilize the moving web.
- 15. The method of claim 1 wherein the airfoil is bowed in the cross-machine direction spreading the web.
- 16. An apparatus for transferring a moving web from a first location to a rotating roll comprising:a roll foil having an internal volume, a front surface, a back surface, and a top surface, the placement of the roll foil defining a region bounded by the rotating roll on a first side, the back surface on a second side, and the web on a third side; a gap in the back surface in fluid communication with the internal volume of the roll foil connected to a source of vacuum; and an airfoil located between the first location and the roll foil whereby the airfoil directs the moving web onto the top surface of the roll foil, and the source of vacuum removes at least a portion of the boundary layer of air traveling with the rotating roll.
- 17. The apparatus of claim 16 wherein the back surface is arcuate.
- 18. The apparatus of claim 16 wherein the gap is located adjacent to the top surface.
- 19. The apparatus of claim 16 wherein the top surface is planer.
- 20. The apparatus of claim 16 wherein a boundary layer reduction member is attached to the roll foil and adapted to reducing some of the boundary layer of air traveling with the rotating roll.
- 21. The apparatus of claim 16 wherein the boundary layer reduction member comprises a wiper attached to the back surface either touching the rotating roll or in close proximity to the rotating roll.
- 22. The apparatus of claim 17 wherein the boundary layer reduction member comprises an air shower blowing against the rotating roll in a direction opposing the rotation.
- 23. The apparatus of claim 22 wherein the air shower comprises a drilled pipe.
- 24. The apparatus of claim 22 wherein the air shower comprises a coanda effect nozzle.
- 25. The apparatus of claim 16 wherein the roll foil has at least one opening located in the front surface in fluid communication with the internal volume.
- 26. The apparatus of claim 25 wherein at least a portion of the opening is located within the thickness of the boundary layer of air traveling with the moving web.
- 27. The apparatus of claim 25 wherein the opening has a plate that can be adjusted changing the size of the opening.
- 28. The apparatus of claim 16 wherein the roll foil has a deflector protruding partially into the moving web attached to the roll foil where the top surface meets the front surface.
- 29. An apparatus for transferring a moving web from a first location to a rotating roll comprising:a roll foil located adjacent a rotating roll having an internal volume, a front surface, and a back surface; a gap in the back surface in fluid communication with the internal volume and connected to a source of vacuum, the gap adapted to removing at least a portion of the boundary layer of air traveling with the rotating roll; and an airfoil located between the first location and the roll foil adapted to directing the moving web onto the roll foil.
- 30. The apparatus of claim 29 wherein the back surface is arcuate.
- 31. The apparatus of claim 29 wherein the roll foil has a top surface adapted to stabilizing the moving web.
- 32. The apparatus of claim 31 wherein the gap is located adjacent the top surface.
- 33. The apparatus of claim 29 wherein a boundary layer reduction member is attached to the back surface.
- 34. The apparatus of claim 33 wherein the boundary layer reduction member comprises a wiper either touching or in close proximity to the rotating roll.
- 35. The apparatus of claim 33 wherein the boundary layer reduction member comprises an air shower blowing against the rotating roll in a direction opposite to the rotation.
- 36. The apparatus of claim 35 wherein the air shower is a drilled pipe.
- 37. The apparatus of claim 35 wherein the air shower is a coanda effect nozzle.
- 38. The apparatus of claim 29 wherein the roll foil has at least one opening located in the front surface in fluid communication with the internal volume.
- 39. The apparatus of claim 38 wherein at least a portion of the opening is located within the thickness of the boundary layer of air traveling with the moving web.
- 40. The apparatus of claim 38 wherein the opening has a plate that can be adjusted changing the size of the opening adapted to regulate the amount of air moving through the opening.
- 41. The apparatus of claim 29 wherein the roll foil has a deflector protruding partially in to the web attached to the roll foil where the top surface meets the front surface.
Parent Case Info
This application claims benefits of Ser. No. 60/150,442 filed on Aug. 24, 1999.
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Provisional Applications (1)
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Number |
Date |
Country |
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60/150442 |
Aug 1999 |
US |