Paper making machine, an extended nip roll and a method of producing tissue paper

Patent metadata

Field	Value
Publication number	US-9410287-B2
Application number	US-201514697188-A
Country	US
Kind code	B2
Filing date	Apr 27, 2015
Priority date	Dec 7, 2011
Publication date	Aug 9, 2016
Grant date	Aug 9, 2016

Abstract

The invention relates to an arrangement arranged to introduce a three-dimensional structure in a paper during production of said paper in a paper making machine ( 1 ). The arrangement comprises a heat roll ( 14 ) arranged to dry a wet paper web and an extended nip roll ( 12 ) arranged to form a transfer nip (TN) with said heat roll ( 14 ). The extended nip roll ( 12 ) is provided with a flexible jacket ( 17 ) arranged around the circumferential area of said extended nip roll ( 12 ). An external surface of said flexible jacket ( 17 ) is provided with a textured portion ( 15 ) and when the wet paper web passes the transfer nip between said extended nip roll ( 12 ) and said heat roll ( 14 ), said textured portion ( 15 ) of the external surface of the flexible jacket ( 17 ) will impart a three-dimensional texture to the paper web.

First claim

That which is claimed:

1. A method of producing tissue paper, wherein the method comprises the steps of:
positioning an extended nip roll relative to a counter roll so as to form a nip with said counter roll, said extended nip roll being provided with a flexible jacket, said flexible jacket having a textured external surface and being arranged in a loop around a circumferential area of said extended nip roll, said textured external surface having knuckles and depressions;
upstream of said nip, injecting stock into a forming section to form an embryonic wet fibrous web on a felt;
passing said wet fibrous web on said felt from said forming section to and through said nip such that said textured external surface of said flexible jacket ( 17 ) of said extended nip roll imparts a three-dimensional structure to said wet fibrous web; and
thereafter, downstream of said nip, drying said wet fibrous web by contacting said wet fibrous web with a heat roll.

2. Method according to claim 1 , wherein:
the paper web has been formed from virgin pulp; and
a linear load in the nip is in the range of 50 kN/m-100 kN/m.

3. Method according to claim 1 , wherein the counter roll is a heat roll.

4. Method according to claim 3 , wherein:
the paper web has been formed from virgin pulp; and
a linear load in the nip is in the range of 50 kN/m-100 kN/m.

5. Method according to claim 1 , wherein the counter roll is a deflection compensated roll.

6. Method according to claim 1 , wherein the counter roll is a grooved roll.

7. Method according to claim 1 , wherein the counter roll is a suction roll.

8. Method according to claim 1 , wherein the knuckles of the textured external surface of said flexible jacket are uniformly distributed knuckles in a number of 25-150 knuckles/cm2.

9. Method according to claim 1 , wherein the knuckles of the textured external surface of said flexible jacket are distributed in an irregular way.

10. Method according to claim 1 , wherein the knuckles of the flexible jacket ( 17 ) are machine-direction oriented.

11. Method according to claim 1 , wherein the textured external surface extends around an entirety of the circumference of the flexible jacket.

12. Method according to claim 1 , wherein the textured external surface extends around only a part of the entire circumference of the flexible jacket ( 17 ).

13. Method according to claim 1 , wherein the textured external surface covers at least 60% of the whole area of an external surface of the flexible jacket ( 17 ).

14. Method according to claim 1 , wherein the textured external surface covers at least 80% of the whole of an external surface of the flexible jacket ( 17 ).

15. Method according to claim 1 , wherein the flexible jacket ( 17 ) is elastically compressible to some extent such that the thickness of the flexible jacket ( 17 ) decreases temporarily as the flexible jacket ( 17 ) passes through a press nip.

16. Method according to claim 1 , wherein the flexible jacket ( 17 ) comprises polyurethane material.

17. Method according to claim 1 , wherein the inner space within the flexible jacket ( 17 ) is configured to be supplied with pressurized air or gas such that the flexible jacket is inflated and under pressure from inside.

18. Method according to claim 1 , wherein:
said nip is a dewatering nip;
said heat roll is positioned relative to said extended nip roll so as to form a transfer nip downstream relative to said dewatering nip; and
said wet fibrous web is supported by said heat roll downstream of said transfer nip.

19. Method according to claim 1 , wherein:
said method further comprises passing a felt through said nip together with said wet fibrous web; and
said felt is positioned intermediate said wet fibrous web and said counter roll when passing through said nip, such that said felt absorbs water pressed out of said wet fibrous web when passing through said nip.

20. Method according to claim 19 , wherein:
said felt further forms a loop around said counter roll, such that said felt separates from said wet fibrous web upon passing through said nip and only said wet fibrous web is supported by said heat roll downstream of said nip.

21. Method according to claim 1 , wherein:
said forming section comprises a forming roll and forming fabric; and
said step of injecting stock into said forming section comprises injecting the stock into a gap between the forming fabric and the felt, said gap being defined, in part, by the forming roll.

22. A method of producing tissue paper, wherein the method comprises the steps of:
positioning an extended nip roll relative to a counter roll so as to form a press nip with said counter roll, said extended nip roll being provided with a flexible jacket, said flexible jacket having a textured external surface and being arranged around a circumferential area of said extended nip roll, said textured external surface extending around an entirety of the circumference of said flexible jacket;
positioning a heat roll relative to said extended nip roll so as to form a transfer nip with said extended nip roll, said transfer nip being downstream relative to said press nip;
upstream of said nip, injecting stock into a forming section to form an embryonic wet fibrous web on a felt;
passing said wet fibrous web on said felt from said forming section to and through said press nip such that said textured external surface of said flexible jacket ( 17 ) of said extended nip roll imparts for a first time a three-dimensional structure to said wet fibrous web; and
passing said wet fibrous web through said transfer nip such that said textured external surface of said flexible jacket ( 17 ) of said extended nip roll imparts for a second time the three-dimensional structure to said wet fibrous web.

23. A method of producing tissue paper, wherein the method comprises the steps of:
positioning an extended nip roll relative to a counter roll so as to form a nip with said counter roll, said extended nip roll being provided with a flexible jacket, said flexible jacket having a textured external surface and being arranged around a circumferential area of said extended nip roll, said textured external surface comprising a plurality of knuckles and depressions;
positioning a heat roll relative to and in contact with said extended nip roll, said contact being downstream relative to said nip;
upstream of said nip, injecting stock into a forming section to form an embryonic wet fibrous web on a felt;
passing said wet fibrous web on said felt from said forming section to and through said nip,
wherein:
said textured external surface of said flexible jacket ( 17 ) of said extended nip roll imparts a three-dimensional structure to said wet fibrous web;
said wet fibrous web is supported by said extended nip roll after said wet fibrous web has passed through said nip; and
said wet fibrous web is supported by said heat roll downstream of said nip.

Assignees

• Valmet Oy

Inventors

• Gustavsson Tord

Classifications

• D21F3/0281 Primary

  in combination with a dryer roll · CPC title

• D21F3/045 Primary

  including at least one extended press nip · CPC title

• D21F11/14

  Making cellulose wadding, filter or blotting paper · CPC title

• D21F11/006

  Making patterned paper · CPC title

• D21F3/086

  having a grooved surface · CPC title