Claims
- 1. A paper machine for manufacturing a fibrous soft paper web, including:
a wet section having a headbox; a forming roll; and inner and outer clothings running around the forming roll, between which clothings the fibrous web is formed; a press section having at least one shoe press having a shoe press roll and a counter roll, said rolls forming an extended press nip, a substantially impermeable belt and a press felt, the substantially impermeable belt and the press felt running through the extended press nip with the fibrous web enclosed therebetween; and a drying section having a drying cylinder and a transfer member which, together with the drying cylinder, forms a transfer nip for transfer of the fibrous web to the drying cylinder, characterized in that
a) the substantially impermeable belt comprises a carrier with a compressible polymer coating on the side facing the paper web, having a hardness in the range from 50 to 97 Shore A, which polymer coating has a web-contacting surface with a pressure-responsive, recoverable degree of roughness, the web-contacting surface having a degree of roughness in unloaded state of Rz=2-80 microns, measured in accordance with ISO 4287, Part I, and a lower degree of roughness of Rz=0-20 microns when the polymer coating is compressed by linear load of 20-220 kN/m on the substantially impermeable belt as measured in a non-extended press nip; b) the press felt is arranged to carry the fibrous web to the press section from the forming roll or from a point situated downstream of the forming roll and upstream of the press section; c) the substantially impermeable belt and the web-carrying press felt are arranged to run together not until they enter the press section to enclose the fibrous web between them, the substantially impermeable belt being arranged to run directly to the press section; d) the substantially impermeable belt is arranged to run from the shoe press to the drying cylinder to carry the fibrous web to said transfer nip; e) the press felt is arranged to run in a direction away from the substantially impermeable belt at a point immediately after the extended press nip and before a water film formed in the extended press nip on the substantially impermeable belt breaks up; and f) a device for applying adhesive is arranged before said transfer nip to apply a continuous adhesive layer on the envelope surface of the drying cylinder and/or on the fibrous web.
- 2. A paper machine as claimed in claim 1, characterized in that said inner clothing in the wet section constitutes a felt, and that this felt is arranged to run through the press section and there to be used also as its press felt.
- 3. A paper machine as claimed in claim 1, characterized in that said inner clothing in the wet section is a fabric, and that a pick-up device is arranged in the loop of the press felt upstream of the press section in order to transfer the fibrous web from the fabric to the press felt.
- 4. A paper machine as claimed in claim 1, characterized in that the press section also includes a roll press arranged upstream of the shoe press and including a suction press roll arranged in the loop of the press felt, and a counter roll arranged in the loop of the substantially impermeable belt.
- 5. A paper machine as claimed in claim 4, characterized in that the counter roll of the shoe press also is the counter roll of the roll press.
- 6. A paper machine as claimed in claim 4, characterized in that the press felt is guided away from the fibrous web in a side loop around the suction press roll and at least one guide roll, which side loop extends from the press nip of the roll press to the extended press nip of the shoe press.
- 7. A paper machine as claimed in claim 1, characterized in that the air permeability of the substantially impermeable belt is less than 6 m3/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”.
- 8. A paper machine as claimed in claim 1, characterized in that the transfer member consists of a transfer roll arranged in the loop of the substantially impermeable belt.
- 9. A paper machine as claimed in claim 1, characterized in that the transfer member consists of the substantially impermeable belt that runs around a predetermined part of the drying cylinder to produce an extended transfer nip.
- 10. A method of manufacturing a fibrous soft paper web in a paper machine, said paper machine including:
a wet section having a headbox; a forming roll; and inner and outer clothings running around the forming roll, between which clothings the fibrous web is to be formed; a press section having at least one shoe press having a shoe press roll and a counter roll, said rolls forming an extended press nip, a substantially impermeable belt and a press felt, the substantially impermeable belt and the press felt running through the extended press nip with the fibrous web enclosed therebetween; and a drying section having a drying cylinder and a transfer member which, together with the drying cylinder, forms a transfer nip for transfer of the fibrous web to the drying cylinder, characterized by
a) performing the pressing with the aid of a substantially impermeable belt that includes a carrier and a compressible polymer coating on the side facing the paper web, said polymer coating having a hardness in the range from 50 to 97 Shore A and a web-contacting surface with a pressure responsive, recoverable degree of roughness, the web-contacting surface having a degree of roughness in unloaded state of Rz=2-80 microns, measured in accordance with ISO 4287, Part I, and a lower degree of roughness of Rz=0-20 microns when the polymer coating is compressed by linear load of 20-220 kN/m on the substantially impermeable belt as measured in a non-extended press nip; b) using the press felt to carry the fibrous web to the press section from the forming roll or roll from a point situated downstream of the forming and upstream of the press section; c) running the substantially impermeable belt and the web-carrying press felt together not until they enter the press section to enclose the fibrous web between them, and running. the substantially impermeable belt directly to the press section; d) running the substantially impermeable belt from the shoe press to the drying cylinder to carry the fibrous web to said transfer nip; e) running the press felt in a direction away from the substantially impermeable belt at a point immediately after the extended press nip and before a water film that is formed on the substantially impermeable belt in the extended press nip breaks up; and f) applying a continuous adhesive layer on the envelope surface of the drying cylinder and web by means of an adhesive applying device at a point before said transfer nip.
- 11. A method as claimed in claim 10, characterized by using a felt as said inner clothing in the wet section, running that felt through the press section, and using that felt also as the press felt of the press section.
- 12. A method as claimed in claim 10, characterized by transferring the fibrous web from said inner of a fabric, to the clothing, which is in the form of a fabric, to the press felt by means of a pick-up device arranged in the loop of the press felt upstream of the press section.
- 13. A method as claimed in claim 10, characterized by dewatering the fibrous web first in a roll press of the press section, said roll press being arranged upstream of the shoe press and including a suction press roll arranged in the loop of the press felt and a counter roll arranged in the loop of the substantially impermeable belt.
- 14. A method as claimed in claim 13, characterized by guiding the press felt away from the fibrous web in a side loop running around the suction press roll and at least one guide roll, said side loop extending from the press nip of the roll press to the extended press nip of the shoe press.
- 15. A method as claimed in claim 10, characterized by using a substantially impermeable belt having an air permeability that is less than 6 m3/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”.
- 16. A method as claimed in claim 10, characterized by using the substantially impermeable belt also as said transfer member that runs around a predetermined part of the drying cylinder to produce an extended transfer nip.
Priority Claims (1)
Number |
Date |
Country |
Kind |
9800948-3 |
Mar 1998 |
SE |
|
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional Application No. 60/088,071, filed Jun. 5, 1998.
Provisional Applications (1)
|
Number |
Date |
Country |
|
60088071 |
Jun 1998 |
US |