Method and apparatus for improving stability of moving webs

• US 20020005264A1
• Filed: 09/05/2001
• Published: 01/17/2002
• Est. Priority Date: 08/24/1999
• Status: Active Grant

• Current Assignee: Kimberly-Clark Worldwide Incorporated (Kimberly-Clark Corporation)
• Original Assignee: Paul Douglas Beuther, Richard Martin Urquhart, Robert Paul Guarnotta, Scott A. Baum, Stephen Percival John Mcgary
• Inventors: Baum, Scott A., McGary, Stephen Percival John, Urquhart, Richard Martin, Beuther, Paul Douglas, Guarnotta, Robert Paul
• Granted Patent: US 6,375,801 B2
• Time in Patent Office: Days
• US Class Current: 162/202
• CPC Class Codes: B65H 23/24 by fluid action, e.g. to retard the running web
• CPC Class Codes: D21F 11/14 Making cellulose wadding, filter or blotting paper
• CPC Class Codes: D21G 3/005 Doctor knifes
• CPC Class Codes: D21G 9/0063 Devices for threading a web tail through a paper-making machine

Abstract

In manufacturing a moving web, such as a tissue sheet, the web is transported at very high speeds, often in an unsupported manner, which can result in unstable operations regarding handling and winding of the web. This is particularly true in the region between the creping blade and the reel for a lightweight, low modulus tissue sheet that is characteristic of a high-quality, soft tissue basesheet. To provide an improved means of controlling the tissue web during manufacture and to improve the manufacturing rate, an apparatus and method of stabilizing the moving web that incorporates a creping blade foil, one or more aerodynamic sheet stabilizing foils, and a roll foil in a specific relationship to each other is disclosed. This method has been shown to improve the stability of a moving tissue web, allow for a higher rate of operation, and enable the production of softer tissue basesheets.

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 1 wherein the region is at a pressure less than atmospheric pressure.

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 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.

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. A method for transferring a moving web from a creping blade in a creping blade holder to a second location comprising:

stabilizing the moving web on a creping blade foil having a top surface, a front edge, and a back edge, the creping blade foil being located beneath the moving web with the front edge touching or in close proximity to the creping blade or the creping blade holder;

directing the moving web towards one or more airfoils located between the creping blade foil and the second location, at least one of the airfoils having 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; and

stabilizing the moving web on the bottom of the airfoils.

17. The method of claim 16 wherein the moving web is directed substantially tangent to the top surface of the creping blade foil leaving the creping blade foil at the back edge.

18. The method of claim 16 wherein a point where the bottom surface of the airfoil joins the nose is located tangent to the top surface of the creping blade foil, the nose of the airfoil is positioned to leave a span from about 4 inches to about 12 inches between the nose of the airfoil and the back edge of the creping blade foil, and the wrap angle of the moving web on the nose of the airfoil is from about 5 to about 25 degrees.

19. The method of claim 16 wherein the creping blade airfoil is attached to a doctor beam and an air shower is located on the doctor beam directing the moving web away from the creping blade foil during a web break.

20. The method of claim 16 wherein more than one airfoil is placed between the creping blade foil and the second location above the moving web intermittently stabilizing the moving web.

21. The method of claim 16 wherein the airfoil is bowed in the cross-machine direction spreading the web.

22. A method for transferring a moving web from a creping blade in a creping blade holder to a rotating roll comprising:

stabilizing the moving web on a creping blade foil having a top surface, a front edge, and a back edge, the creping blade foil being located beneath the moving web with the front edge touching or in close proximity to the creping blade or the creping blade holder;

stabilizing the moving web on at least one airfoil located between the creping blade foil and a 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 whereby the moving web is transferred to the rotating roll with minimal disturbance.

23. The method of claim 22 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 transfer to the rotating roll.

24. The method of claim 22 wherein the region is at a pressure less than atmospheric.

25. The method of claim 22 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.

26. The method of claim 25 wherein the boundary layer reduction member comprises a wiper either touching the rotating roll or in close proximity to the rotating roll.

27. The method of claim 25 wherein the boundary reduction member comprises an air shower blowing against the rotating roll in a direction opposing the rotation.

28. The method of claim 27 wherein the air shower is a drilled pipe.

29. The method of claim 27 wherein the air shower is a coanda effect nozzle.

30. The method of claim 22 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.

31. The method of claim 30 wherein at least a portion of the opening is located within the thickness of the boundary layer of air traveling with the moving web.

32. The method of claim 30 wherein the airflow'"'"'s entering the gap and the opening can be adjusted by a movable plate that changes the size of the opening.

33. The method of claim 23 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 between the moving web and the top surface.

34. The method of claim 22 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 top, the top being another curved surface extending from the nose to the tail meeting with the bottom at an edge.

35. The method of claim 22 wherein two or more airfoils are placed between the creping blade foil and the roll foil above the moving web intermittently stabilizing the moving web.

36. The method of claim 22 wherein the airfoil is bowed in the cross-machine direction to spread the web.

37. The method of claim 22 wherein the moving web is directed substantially tangent to the top surface of the creping blade foil leaving the creping blade foil at the back edge.

38. The method of claim 22 wherein the airfoil is located from about 4 inches to about 12 inches from the back edge of the creping blade foil.

39. An apparatus for transferring a moving web 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; and

a boundary layer reduction member attached to the roll foil adapted to reducing the boundary layer of air traveling with the rotating roll; and

a gap in the back surface in fluid communication with the internal volume of the roll foil connected to a source of vacuum.

40. The apparatus of claim 39 wherein the back surface is arcuate and substantially matches the radius of the rotating roll.

41. The apparatus of claim 39 wherein the gap is located adjacent to the top surface.

42. The apparatus of claim 39 wherein the top surface is planer.

43. The apparatus of claim 39 wherein the boundary layer reduction member comprises a wiper connected to the back surface either touching the rotating roll or in close proximity to the rotating roll.

44. The apparatus of claim 39 wherein the boundary reduction member comprises an air shower blowing against the rotating roll in a direction opposing the rotation.

45. The apparatus of claim 44 wherein the air shower is a drilled pipe.

46. The apparatus of claim 44 wherein the air shower is a coanda effect nozzle.

47. The apparatus of claim 39 wherein the roll foil has at least one opening located in the front surface in fluid communication with the internal volume.

48. The apparatus of claim 47 wherein at least a portion of the opening is located within the thickness of the boundary layer of air traveling with the web.

49. The apparatus of claim 47 wherein the opening has a plate that can be adjusted changing the size of the opening.

50. The apparatus of claim 39 wherein the roll foil has a deflector protruding partially into the web attached to the roll foil where the top surface meets the front surface.

51. An apparatus for stabilizing and transferring a moving web 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 adapted to removing at least a portion of the boundary layer of air traveling with the rotating roll; and

a boundary layer reduction member attached to the back surface.

52. The apparatus of claim 51 wherein the back surface is arcuate and substantially matches the radius of the rotating roll.

53. The apparatus of claim 51 wherein the roll foil has a planer top surface adapted to stabilizing the moving web.

54. The apparatus of claim 53 wherein the gap is located adjacent to the top surface.

55. The apparatus of claim 51 wherein the boundary layer reduction member comprises a wiper either touching the rotating roll or in close proximity to the rotating roll.

56. The apparatus of claim 51 wherein the boundary layer reduction member comprises an air shower blowing against the rotating roll in a direction opposite to the rotation.

57. The apparatus of claim 56 wherein the air shower is a drilled pipe.

58. The apparatus of claim 56 wherein the air shower is a coanda effect nozzle.

59. The apparatus of claim 51 wherein the roll foil has at least one opening located in the front surface in fluid communication with the internal volume.

60. The apparatus of claim 59 wherein at least a portion of the opening is located within the thickness of the boundary layer of air traveling with the moving web.

61. The apparatus of claim 59 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.

62. The apparatus of claim 53 wherein the roll foil has a deflector protruding partially into the web attached to the roll foil where the top surface meets the front surface.