Claims
- 1. A paper machine for texturing and drying a wet fibrous paper web, said paper machine comprising:
a press having two cooperating press members forming a press nip between the press members for pressing the fibrous web and removing water from the web; a heated drying cylinder downstream of the press for receiving the pressed fibrous web about a portion of the surface of the cylinder and thereby further drying the fibrous web by evaporating at least part of the water remaining in the web; and a substantially impermeable texturing belt having a web-contacting surface defining a multitude of regularly distributed depressions and surface portions located between the depressions, said substantially impermeable texturing belt being arranged to pass with the fibrous web through the press such that the depressions of the web-contacting surface initially form in the fibrous web an equivalent textured pattern having thicker and thinner portions, and said substantially impermeable texturing belt being further arranged to then carry the fibrous web to the heated drying cylinder such that the surface portions of the belt engage the thinner portions of the web against the surface of the cylinder and the water in the thicker portions of the web is caused to evaporate.
- 2. A paper machine as claimed in claim 1 wherein said substantially impermeable texturing belt further comprises a back layer and a web-contacting layer comprising a compressible polymer layer having a hardness in the range from 50 to 97 Shore A, and defining the web-contacting surface, said web-contacting surface having a pressure responsive, recoverable degree of roughness in an unloaded state of Rz=2 to 80 μm, measured in accordance with ISO 4287, Part I, and a lower degree of roughness of Rz=0 to 20 μm when the polymer layer is compressed by a linear load of 20 to 200 kN/m as measured in a nonextended press nip.
- 3. A paper machine as claimed in claim 1 wherein said substantially impermeable texturing belt further comprises a back layer and a web-contacting layer, said web-contacting layer being formed from a fabric coated with a polymer so as to form a structure comprising said depressions and said surface portions therebetween, said surface portions having an arched or convex shape.
- 4. A paper machine as claimed in claim 3 wherein said arched or convex surface portions comprise a plurality of knuckles formed by fabric threads extending in one and the same direction and which are uniformly distributed in a number of 25 to 150 knuckles/cm2.
- 5. A paper machine as claimed in claim 2 wherein the depressions take up from 20% up to 50% of the web-contacting surface.
- 6. A paper machine as claimed in claim 2 wherein the depressions are continuous grooves in the web-contacting surface, which grooves are arranged in one or more groups, the grooves in one and the same group extending in one and the same direction.
- 7. A paper machine as claimed in claim 6 wherein the distance (a) between two grooves in one and the same group is within the interval 1 to 3 mm, the width (b) of the groove is within the interval 0.5 to 1.0 mm and its depth (c) is within the interval 0.1 to 1.0 mm.
- 8. A paper machine as claimed in claim 6 wherein the grooves extend in the machine direction or form an angle of 10° to 80° therewith.
- 9. A paper machine as claimed in claim 6, wherein the grooves are arranged in a first group in which the grooves extend in one and the same direction, and in a second group in which the grooves extend in one and the same direction forming an angle a with the direction of the grooves in the first group, which angle α is 10° to 170°.
- 10. A paper machine as claimed in claim 6 wherein the grooves are straight or wave shaped.
- 11. A paper machine as claimed in claim 2 wherein the depressions are hollows of the same or similar geometric shapes including circular, elliptical, or polygon shape, the largest dimension of each lying within the interval 0.5 to 3 mm and depth within the interval 0.5 to 1 mm.
- 12. A paper machine as claimed in claim 2 wherein at least some of the depressions are hollows of non-geometric symbol shapes including numbers, letters, trade or company symbols with depths within the interval 0.5 to 1 mm.
- 13. A paper machine as claimed in claim 1 further comprising a felt arranged to run through the press section against the wet web for receiving water pressed from the web.
- 14. A paper machine as claimed in claim 1 wherein the press comprises at least one shoe press and the press members comprise a shoe press roll and a counter roll to form an extended nip therebetween.
- 15. A paper machine as claimed in claim 14 further comprising another press arranged upstream of the shoe press and the press members comprise a suction press roll and a press roll.
- 16. A paper machine as claimed in claim 1 and further comprising a headbox for forming the web against the substantially impermeable textured belt.
- 17. A paper machine as claimed in claim 1 wherein the air permeability of the substantially impermeable texturing belt is less than 6m3/m2/minute, measured in accordance with the procedure described in “Standard Test Method for Air Permeability of-Textile Fabrics, ASTM D 737-75, American Society of Testing and Materials”.
- 18. A paper machine as claimed in claim 1 further comprising a transfer roll arranged to engage the substantially impermeable texturing belt and paper web against the surface of the drying cylinder.
- 19. A paper machine belt for texturing and drying a wet fibrous paper web and advancing the web between a press and a drying cylinder, said belt comprising:
a substantially impermeable texturing belt having a web-contacting surface defining a multitude of regularly distributed depressions and surface portions located between the depressions, said substantially impermeable texturing belt being adapted to pass with the fibrous web through the press such that the depressions of the web-contacting surface initially form in the fibrous web an equivalent textured pattern having thicker and thinner portions, and said substantially impermeable belt being further adapted to then carry the fibrous web to the heated drying cylinder such that the surface portions of the belt engage the thinner portions of the web against the surface of the cylinder and the water in the thicker portions of the web is caused to evaporate.
- 20. A paper machine belt as claimed in claim 19 wherein said substantially impermeable texturing belt further comprises a back layer and a web-contacting layer comprising a compressible polymer layer having a hardness in the range from 50 to 97 Shore A, and defining the web-contacting surface, said web-contacting surface having a pressure responsive, recoverable degree of roughness in an unloaded state of Rz=2 to 80 μm, measured in accordance with ISO 4287, Part I, and a lower degree of roughness of Rz=0 to 20 μm when the polymer layer is compressed by a linear load of 20 to 200 kN/m as measured in a nonextended press nip.
- 21. A paper machine belt as claimed in claim 19 wherein said substantially impermeable texturing belt further comprises a back layer and a web-contacting layer, said web-contacting layer being formed from a fabric coated with a polymer so as to form a structure comprising said depressions and said surface portions therebetween, said surface portions having an arched or convex shape.
- 22. A paper machine belt as claimed in claim 21 wherein said arched or convex surface portions comprise a plurality of knuckles formed by fabric threads extending in one and the same direction and which are uniformly distributed in a number of 25 to 150 knuckles/cm2.
- 23. A paper machine belt as claimed in claim 20 wherein the depressions take up from 20% up to 50% of the web-contacting surface.
- 24. A paper machine belt as claimed in claim 20 wherein the depressions are continuous grooves in the web-contacting surface, which grooves are arranged in one or more groups, the grooves in one and the same group extending in one and the same direction.
- 25. A paper machine belt as claimed in claim 24 wherein the distance (a) between two grooves in one and the same group is within the interval 1 to 3 mm, the width (b) of the groove is within the interval 0.5 to 1.0 mm and its depth (c) is within the interval 0.1 to 1.0 mm.
- 26. A paper machine belt as claimed in claim 24 wherein the grooves extend in the machine direction or form an angle of 10° to 80° therewith.
- 27. A paper machine belt as claimed in claim 24, wherein the grooves are arranged in a first group in which the grooves extend in one and the same direction, and in a second group in which the grooves extend in one and the same direction forming an angle a with the direction of the grooves in the first group, which angle α is 10° to 170°.
- 28. A paper machine belt as claimed in claim 24 wherein the grooves are straight or wave shaped.
- 29. A paper machine belt as claimed in claim wherein the depressions are hollows of the same or similar geometric shapes including circular, elliptical, or polygon shape, the largest dimension of each lying within the interval 0.5 to 3 mm and depth within the interval 0.5 to 1 mm.
- 30. A paper machine belt as claimed in claim 20 wherein at least some of the depressions are hollows of non-geometric symbol shapes including numbers, letters, trade or company symbols with depths within the interval 0.5 to 1 mm.
- 31. A paper machine belt as claimed in claim 19 wherein the air permeability of the substantially impermeable texturing belt is less than 6m3/m2/minute, measured in accordance with the procedure described in “Standard Test Method for Air Permeability of Textile Fabrics, ASTM D 737-75, American Society of Testing and Materials”.
- 32. A method of texturing and drying a wet fibrous paper web comprising the steps of:
advancing the wet fibrous web through a press and pressing the fibrous web to remove water from the web; advancing the fibrous web to a heated drying cylinder; extending the fibrous web about a portion of the heated drying cylinder to further dry the fibrous web by evaporating at least part of the water remaining in the web; carrying the fibrous web between the press and the drying cylinder with a substantially impermeable texturing belt which extends through the press and to the surface of the drying cylinder for engaging the fibrous web against the drying cylinder, and texturing the fibrous web with a web-contacting surface of the substantially impermeable belt which defines a multitude of regularly distributed depressions, said texturing step occurring while the belt and fibrous web are advancing through the press and as the fibrous web is engaged against the drying cylinder so that the depressions form a textured pattern on the fibrous web
- 33. A method as claimed in claim 32 further comprising the steps of:
advancing a press felt through the press with the fibrous web to receive water pressed therefrom; and advancing the press felt immediately after the press in a direction away from the impermeable texturing belt before a water film formed in the press nip on the substantially impermeable texturing belt breaks up.
- 34. A method as claimed in claim 32 further comprising the step of applying a continuous layer of adhesive on the surface of the drying cylinder and/or the textured fibrous web for promoting adhesion of the fibrous web to the drying cylinder.
- 35. A method as claimed in claim 33 further comprising the step of carrying the fibrous web to the press on the press felt.
- 36. A method as claimed in claim 32 wherein said pressing step is performed by a shoe press with an extended nip.
- 37. A method as claimed in claim 36 further comprising the step of pressing the fibrous web in a roll press arranged upstream of the shoe press and including a suction press roll and a counter roll.
- 38. A method as claimed in claim 32 wherein the substantially impermeable texturing belt also carries the fibrous web from the headbox for forming the web to the press.
- 39. A method as claimed in claim 32 wherein the fibrous web is engaged against the drying cylinder with the assistance of a transfer roll.
- 40. A method as claimed in claim 32 wherein the fibrous web is engaged against the drying cylinder by wrapping the web around at least a portion of the drying cylinder.
Priority Claims (1)
Number |
Date |
Country |
Kind |
9800949-1 |
Mar 1998 |
SE |
|
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. patent application No. 08/992,285, filed Dec. 17, 1997 and ______ filed ______ , both of which are incorporated herein by reference.
Continuations (1)
|
Number |
Date |
Country |
Parent |
09212798 |
Dec 1998 |
US |
Child |
09916756 |
Jul 2001 |
US |