Papermaking machine with press section

Abstract

A machine or apparatus for producing structured tissue or towel using a press section.

Claims

1. A papermaking machine comprising: (A) a wet section for forming a nascent paper web, the wet section comprising a gap former into which is deposited a paper slurry from a headbox to form the nascent paper web, the gap former comprising: (i) a forming wire; and (ii) a dewatering fabric, the dewatering fabric running in an endless loop about a forming roll, a suction roll and a first press element; (B) a first dewatering section comprising the suction roll and a first steam box through which passes the nascent paper web to form a partially dewatered paper web; (C) a press section for pressing the partially dewatered paper web, the press section comprising: (i) the first press element with an inside surface of the dewatering fabric in contact with the first press element; (ii) a structuring belt with an inside surface of the structuring belt in contact with a suction element; and (iii) a first nip, formed between the dewatering fabric in contact with the first press element and the structuring belt in contact with the suction element, in which the partially dewatered paper web is pressed and transferred to the structuring belt; (D) a second dewatering section comprising at least one of: (i) a second steam box and a vacuum device; or (ii) a hot air hood and an exhaust duct, through which passes the partially dewatered paper web travelling on the structuring belt; and (E) a drying section for drying the partially dewatered paper web to form a dried web, the drying section comprising: (i) a second press element with the inside surface of the structuring fabric in contact with the second press element; (ii) a steam heated cylinder; and (iii) a second nip, formed between the structuring fabric in contact with the second press element and the steam heated cylinder, in which the partially dewatered paper web is pressed and transferred to the steam heated cylinder, wherein the dried web is creped off the steam heated cylinder.

2. The papermaking machine of claim 1, wherein the dewatering fabric comprises polymer monofilaments or multi-filamentous yarns, needled with fine synthetic batt fibers.

3. The papermaking machine of claim 2, wherein the dewatering fabric further comprises absorbent porous materials.

4. The papermaking machine of claim 2, wherein the dewatering fabric further comprises extruded polymer netting.

5. The papermaking machine of 1, wherein the first press element is an extended nip press.

6. The papermaking machine of claim 5, wherein the press section extended nip press is a shoe press or belt press.

7. The papermaking machine of claim 6, wherein the press section extended nip press comprises a sleeve which is plain grooved, blind drilled, through drilled, or a combination thereof.

8. The papermaking machine of claim 1, wherein the suction element is a suction pressure roll.

9. The papermaking machine of claim 8, wherein the suction pressure roll comprises a roll cover made of polymeric material, where the cover of the press is grooved, blind drilled, through drilled, or a combination thereof.

10. The papermaking machine of claim 1, wherein the suction element is a vacuum box or suction pickup shoe.

11. The papermaking machine of claim 1, wherein the structuring belt is of a type selected from the group consisting of: a woven fabric, a woven fabric with an overlaid polymer, welded strips of polymeric material or extruded sheets of polymer which are etched by punching, drilling, or laser drilling, woven fabrics laminated with a 3-D printed web contacting or structuring layer, a structuring fabric made entirely from 3-D printed material, a laminated structuring fabric with a web-contacting layer made from extruded polymer netting or 3-D printed material laminated to a woven fabric or a dewatering fabric, and a fabric comprising a web-contacting layer made from extruded polymer netting or 3-D printed material laminated to a triple layer woven fabric which is then laminated to a dewatering fabric where fine synthetic batt fibers of the dewatering fabric are needled into the dewatering fabric and through a bottom layer of the triple layer woven fabric of the web contacting layer after the web contacting layer has been laminated to the dewatering fabric.

12. The papermaking machine of claim 1, wherein the structuring belt is a laminated fabric comprising a web contacting layer made from extruded polymer netting or 3-D printed material and a non-web contacting layer made of a woven fabric or a dewatering fabric.

13. The papermaking machine of claim 1, wherein the drying section press element comprises a shoe press, a suction pressure roll, or a plain press roll with a narrow nip width and high nip intensity.

14. The papermaking machine of claim 13, wherein the drying section press element is a shoe press, and the shoe press comprises a sleeve and the sleeve of the press is plain, grooved, blind drilled, through drilled, or a combination thereof.

15. The papermaking machine of claim 13, wherein the drying section press element is a suction pressure roll, and the section pressure roll has a roll cover made of rubber, polyurethane, or other polymers and the cover is grooved, blind drilled, through drilled, or a combination thereof.

16. The papermaking machine of claim 1, wherein the vacuum device comprises a vacuum roll, vacuum box, or vacuum shoe.

17. The papermaking machine of claim 1, wherein the first press element is a conventional plain press roll with a narrow nip width and high nip intensity with a rubber or polyurethane cover that is flat or has blind drilled holes and/or grooves.

18. The papermaking machine of claim 1, wherein the first press element is a capillary dewatering roll.

19. The papermaking machine of claim 1, wherein travel speed of the dewatering fabric is the same or different from travel speed of the structuring belt.

20. The papermaking machine of claim 1, wherein the structuring belt functions as a detwatering belt.

21. A papermaking machine comprising: (A) a wet section for forming a nascent paper web, the wet section comprising a gap former into which is deposited a paper slurry from a headbox to form the nascent paper web, the gap former comprising: (i) a forming wire; and (ii) a dewatering fabric, the dewatering fabric running in an endless loop about a forming roll and a first press element; (B) a press section for pressing a partially dewatered paper web formed from the nascent web, the press section comprising: (i) the first press element with an inside surface of the dewatering fabric in contact with the first press element; (ii) a structuring belt with an inside surface of the structuring belt in contact with a suction element; and (iii) a first nip, formed between the dewatering fabric in contact with the first press element and the structuring belt in contact with the suction element, in which the partially dewatered paper web is pressed and transferred to the structuring belt; (C) a dewatering section comprising at least one of: (i) a steam box and a vacuum device; or (ii) a hot air hood and an exhaust duct, through which passes the partially dewatered paper web travelling on the structuring belt; and (D) a drying section for drying the partially dewatered paper web to form a dried web, the drying section comprising: (i) a second press element with the inside surface of the structuring fabric in contact with the second press element; (ii) a steam heated cylinder; and (iii) a second nip, formed between the structuring fabric in contact with the second press element and the steam heated cylinder, in which the partially dewatered paper web is pressed and transferred to the steam heated cylinder, wherein the dried web is creped off the steam heated cylinder.

22. A papermaking machine comprising: (A) a wet section for forming a nascent paper web, the wet section comprising a gap former into which is deposited a paper slurry from a headbox to form the nascent paper web, the gap former comprising: (i) a forming wire; and (ii) a dewatering fabric, the dewatering fabric running in an endless loop about a forming roll, a suction roll and a first press element; (B) a dewatering section comprising the suction roll and a steam box through which passes the nascent paper web to form a partially dewatered paper web; (C) a press section for pressing the partially dewatered paper web, the press section comprising: (i) the first press element with an inside surface of the dewatering fabric in contact with the first press element; (ii) a structuring belt with an inside surface of the structuring belt in contact with a suction element; and (iii) a first nip, formed between the dewatering fabric in contact with the first press element and the structuring belt in contact with the suction element, in which the partially dewatered paper web is pressed and transferred to the structuring belt; and (D) a drying section for drying the partially dewatered paper web to form a dried web, the drying section comprising: (i) a second press element with the inside surface of the structuring fabric in contact with the second press element; (ii) a steam heated cylinder; and (iii) a second nip, formed between the structuring fabric in contact with the second press element and the steam heated cylinder, in which the partially dewatered paper web is pressed and transferred to the steam heated cylinder, wherein the dried web is creped off the steam heated cylinder.

23. A papermaking machine comprising: (A) a wet section for forming a nascent paper web, the wet section comprising a gap former into which is deposited a paper slurry from a headbox to form the nascent paper web, the gap former comprising: (i) a forming wire; and (ii) a dewatering fabric, the dewatering fabric running in an endless loop about a forming roll and a first press element; (B) a press section for pressing a partially dewatered paper web formed from the nascent web, the press section comprising: (i) the first press element with an inside surface of the dewatering fabric in contact with the first press element; (ii) a structuring belt with an inside surface of the structuring belt in contact with a suction element; and (iii) a first nip, formed between the dewatering fabric in contact with the first press element and the structuring belt in contact with the suction element, in which the partially dewatered paper web is pressed and transferred to the structuring belt; (C) a drying section for drying the partially dewatered paper web to form a dried web, the drying section comprising: (i) a second press element with the inside surface of the structuring fabric in contact with the second press element; (ii) a steam heated cylinder; and (iii) a second nip, formed between the structuring fabric in contact with the second press element and the steam heated cylinder, in which the partially dewatered paper web is pressed and transferred to the steam heated cylinder, wherein the dried web is creped off the steam heated cylinder.

24. A method for making paper comprising: (A) forming a nascent paper web by depositing a paper slurry from a headbox into a gap former of a wet section of a papermaking machine, the gap former comprising: (i) a forming wire; and (ii) a dewatering fabric, the dewatering fabric running in an endless loop about a forming roll, a suction roll and a first press element; (B) forming a partially dewatered paper web by passing the nascent paper web through a first dewatering section of the papermaking machine comprising the suction roll and a first steam box; (C) pressing the partially dewatered paper web at a press section of the papermaking machine, the press section comprising: (i) the first press element with an inside surface of the dewatering fabric in contact with the first press element; (ii) a structuring belt with an inside surface of the structuring belt in contact with a suction element; and (iii) a first nip, formed between the dewatering fabric in contact with the first press element and the structuring belt in contact with the suction element, in which the partially dewatered paper web is pressed and transferred to the structuring belt; (D) passing the partially dewatered paper web travelling on the structuring belt through a second dewatering section of the papermaking machine comprising at least one of: (i) a second steam box and a vacuum device; or (ii) a hot air hood and an exhaust duct; (E) drying the partially dewatered paper web at a drying section of the papermaking machine to form a dried web, the drying section comprising: (i) a second press element with the inside surface of the structuring fabric in contact with the second press element; (ii) a steam heated cylinder; and (iii) a second nip, formed between the structuring fabric in contact with the second press element and the steam heated cylinder, in which the partially dewatered paper web is pressed and transferred to the steam heated cylinder, wherein the structuring fabric at the second nip is compressed resulting in a top plane of a first element of the structuring fabric being in substantially the same plane as a top plane of a second element of the structuring fabric; and (F) creping the dried web off the steam heated cylinder.

25. A papermaking machine comprising: a wet section for forming a nascent paper web, the wet section comprising: a forming wire; a dewatering fabric, the dewatering fabric running in an endless loop about a forming roll, a suction roll and a first press element; and a first nip formed between the forming wire and the dewatering fabric into which is deposited a paper slurry from a headbox to form the nascent paper web; a first dewatering section comprising the suction roll and a first steam box through which passes the nascent paper web to form a partially dewatered paper web; a press section for pressing the partially dewatered paper web, the press section comprising: the first press element with an inside surface of the dewatering fabric in contact with the first press element; a structuring belt with an inside surface of the structuring belt in contact with a suction element; and a second nip, formed between the dewatering fabric in contact with the first press element and the structuring belt in contact with the suction element, in which the partially dewatered paper web is pressed and transferred to the structuring belt; a second dewatering section comprising a second steam box and a vacuum device through which passes the partially dewatered paper web travelling on the structuring belt; and a drying section for drying the partially dewatered paper web to form a dried web, the drying section comprising: a second press element with the inside surface of the structuring fabric in contact with the second press element; a steam heated cylinder; and a third nip, formed between the structuring fabric in contact with the second press element and the steam heated cylinder, in which the partially dewatered paper web is pressed and transferred to the steam heated cylinder, wherein the dried web is creped off the steam heated cylinder.

26. The papermaking machine of claim 25, wherein the dewatering fabric comprises polymer monofilaments or multi-filamentous yarns, needled with fine synthetic batt fibers.

27. The papermaking machine of claim 26, wherein the dewatering fabric further comprises absorbent porous materials.

28. The papermaking machine of claim 26, wherein the dewatering fabric further comprises extruded polymer netting.

29. The papermaking machine of 25, wherein the first press element is an extended nip press.

30. The papermaking machine of claim 29, wherein the press section extended nip press is a shoe press or belt press.

31. The papermaking machine of claim 30, wherein the press section extended nip press comprises a sleeve which is plain grooved, blind drilled, through drilled, or a combination thereof.

32. The papermaking machine of claim 25, wherein the suction element is a suction pressure roll.

33. The papermaking machine of claim 32, wherein the suction pressure roll comprises a roll cover made of a polymeric material, where the cover of the press is grooved, blind drilled, through drilled, or a combination thereof.

34. The papermaking machine of claim 25, wherein the suction element is a vacuum box or suction pickup shoe.

35. The papermaking machine of claim 25, wherein the structuring belt is of a type selected from the group consisting of: a woven fabric, a woven fabric with an overlaid polymer, welded strips of polymeric material or extruded sheets of polymer which are etched by punching, drilling, or laser drilling, woven fabrics laminated with a 3-D printed web contacting or structuring layer, a structuring fabric made entirely from 3-D printed material, and a laminated structuring fabric with a web-contacting layer made from extruded polymer netting or 3-D printed material laminated to a woven fabric or a dewatering fabric.

36. The papermaking machine of claim 25, wherein the structuring belt is a laminated fabric comprising a web contacting layer made from extruded polymer netting or 3-D printed material and a non-web contacting layer made of a woven fabric or a dewatering fabric.

37. The papermaking machine of claim 25, wherein the drying section press element comprises a shoe press, a suction pressure roll, or a plain press roll with a narrow nip width and high nip intensity.

38. The papermaking machine of claim 37, wherein the drying section press element is a shoe press, and the shoe press comprises a sleeve and the sleeve of the press is plain, grooved, blind drilled, through drilled, or a combination thereof.

39. The papermaking machine of claim 37, wherein the drying section press element is a suction pressure roll, and the suction pressure roll has a roll cover made of polymeric material and the cover is grooved, blind drilled, through drilled, or a combination thereof.

40. The papermaking machine of claim 25, wherein the vacuum device comprises a vacuum roll, vacuum box, or vacuum shoe.

41. The papermaking machine of claim 25, wherein the first press element is a plain press roll with a narrow nip width and high nip intensity with a rubber or polyurethane cover that is flat or has blind drilled holes and/or grooves.

42. The papermaking machine of claim 25, wherein the first press element is a capillary dewatering roll.

43. The papermaking machine of claim 25, wherein travel speed of the dewatering fabric is the same or different from travel speed of the structuring belt.

44. The papermaking machine of claim 25, wherein the structuring belt functions as a detwatering belt.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The features and advantages of exemplary embodiments of the present invention will be more fully understood with reference to the following, detailed description when taken in conjunction with the accompanying figures, wherein:

(2) FIG. 1 is a block diagram of a papermaking machine according to an exemplary embodiment of the present invention;

(3) FIG. 2 is a block diagram of a papermaking machine according to another exemplary embodiment of the present invention;

(4) FIG. 3 is a micrograph showing a cross-section of a web contacting layer of a structuring fabric according to an exemplary embodiment of the present invention;

(5) FIG. 4 illustrates contact area of a structured tissue belt assembly according to an exemplary embodiment of the present invention as the belt approaches a nip between a press roll and a Yankee dryer;

(6) FIG. 5 illustrates contact area of the structured tissue belt assembly of FIG. 4 within the nip; and

(7) FIG. 6 is a photograph showing a bath tissue product according to an exemplary embodiment of the present invention.

DETAILED DESCRIPTION

(8) FIG. 1 shows a block diagram of a papermaking machine, generally designated by reference number 1, according to an exemplary embodiment of the present invention. The papermaking machine 1 includes a first exterior layer fan pump 28, a core layer fan pump 29, and a second exterior layer fan pump 30. The fan pumps 28, 29, 30 move a dilute slurry of fiber and chemicals to a triple layer headbox 3 which deposits the slurry into a nip formed by a forming roll 2, a breast roll 1, an outside forming fabric 40 and an inside dewatering fabric 5.

(9) The outer forming fabric is preferably a triple layer forming fabric, such as, for example, the T-Star AJ-494 Forming Fabric provided by Asten Johnson (4399 Corporate Road, Charleston, S.C., USA 29405), but can be any other forming fabric design. Forming fabric 4 runs in an endless loop around a plurality of guide rolls 8 to return back to the breast roll 40.

(10) The forming roll 2 is preferably a solid rubber covered roll, but can be any other type of forming roll, such as an impermeable or permeable roll with an internal vacuum box, and may be covered with a smooth or textured material. The forming roll cover may be made from a material selected from, but not limited to rubber, or polyurethane. The cover may also have a pattern of filaments made of metal or polymer to create a texture.

(11) Excess water may be doctored from the forming roll using a single, double, or triple doctor 7A to aid in removing water that may be wringing the roll and rewetting the web. The water is captured in a pan 14A and directed off the machine to prevent stock and water buildup on the machine frame, which may otherwise lead to drips and holes in the tissue webs and subsequent sheet-breaks and lost operating time.

(12) The dewatering fabric 5 is typically comprised of large polymer monofilaments or multi-filamentous yarns, needled with fine synthetic batt fibers to form a smooth surface for even web pressing. However, any type of dewatering fabric can be used, such as, for example, the fabric shown in FIG. 14A of U.S. Pat. No. 7,476,294, the contents of which are incorporated herein by reference in their entirety, where other absorbent porous materials are incorporated. Another example of a fabric structure that may be used as the dewatering fabric 5 is described in U.S. Pat. No. 10,208,426, and includes nylon woven monofilaments, laminated to extruded polymer netting for compression resistance, and then needle punched with batt fiber on the surface and through the structure.

(13) After separation of the forming and dewatering fabric, a vacuum transfer box 6 is used to assist in nascent web adherence to the dewatering fabric 5. The dewatering fabric 5 then travels with the web across a dewatering suction device comprised of suction roll 9 and steam box 10. In other exemplary embodiments, the dewatering suction device may be omitted. The steambox applies approximately 0.1-1.0 ton of steam per ton of paper to heat the water in the web and lower the viscosity to improve water removal through the suction roll 9. Other dewatering devices known in the art can be used, such as, for example, a vacuum box or suction shoe, which are both non-rotating water removal devices and therefore not preferred as they can cause wear to the dewatering fabric.

(14) The web travels across the dewatering device and into the press section comprised of a press element 11, suction element 12, the dewatering fabric 5, and structuring fabric 13. Press element 11 is preferably an extended nip press, such as, for example, a shoe press or belt press. Extended nip presses extend the time that the paper web remains in the press nip. The amount of water removed in the nip is proportional to the magnitude and the duration of the pressure applied to the paper web. Using an extended nip, the manufacturer can utilize less pressure to achieve the same amount of dewatering while maintaining web bulk and preserving fabric life. Examples of a shoe press include the Advantage ViscoNip Press from Valmet (Keilasatama 5/PO Box 11 FI-02150 ESPOO, FINLAND), and the NipcoFlex T from Voith (St. Poltener Straße 43 89522 Heidenheim Germany). FIG. 16 of U.S. Pat. No. 7,351,307, the contents of which are incorporated herein by reference in their entirety, shows an example of a suitable belt press. In exemplary embodiments, the shoe press cover may be made of rubber, polyurethane, or other material with through drilled holes, blind drilled holes, grooves, or a combination thereof. Suction element 12 is preferably a suction pressure roll which contains a rubber, polyurethane, or other material cover with through drilled holes, blind drilled holes, grooves, or a combination thereof. Other dewatering devices known in the art can be used, such as, for example, a vacuum box or suction shoe (pickup shoe), which are both non-rotating water removal devices and therefore not preferred as they can cause wear to the structuring fabric. The press section may instead include conventional plain press rolls with a narrow nip width and high nip intensity, or capillary rolls (as described in U.S. Pat. No. 5,701,682, the contents of which are incorporated herein by reference in their entirety), or a combination thereof, although this is not preferred because the web would lose bulk and quality. In an exemplary embodiment, a machine direction dominated pattern on the structuring fabric lines up opposite the grooves on the suction pressure roll for enhanced water removal. As used herein, the term narrow nip width is intended to mean a nip width of less than about 9 cm or from about 4 cm to about 8 cm or less than about 8 cm, and high nip intensity is intended to mean a nip intensity greater than about 5,000 kN/m.sup.2 or from about 6,000 to about 12,000 kN/m.sup.2 or greater than about 6,000 kN/m.sup.2.

(15) The structuring fabric 13 can be of any type described in the background section of this patent application, such as a woven fabric, a woven fabric with an overlaid polymer, welded strips of polymeric material or extruded sheets of polymer which are etched by punching, drilling, or laser drilling, woven fabrics laminated with a 3-D printed web contacting or structuring layer, or a structuring fabric made entirely from 3-D printed material As the web travels on the dewatering fabric 5 through the first press nip, the dewatering fabric 5 and the structuring fabric 13 are subjected to compression and expansion, thereby uptaking and removing water from both sides of the web. Vacuum applied by the suction element 12 also draws the water into the structuring fabric 13 and pulls the fiber into the structuring fabric 13 to develop texture and bulk in the web. Water removed at vacuum element 12 is deposited in pan 14B, and excess water that may be wringing the roll and rewetting the web is doctored from the element using a single, double, or triple doctor 7B.

(16) In preferred embodiments the structuring fabric is a laminated fabric with a web-contacting layer made from extruded polymer netting or 3-D printed material laminated to a woven fabric or a dewatering fabric as described in U.S. Pat. No. 10,208,426. In another preferred embodiment the structuring fabric has a web contacting layer comprising extruded polymer netting or 3-D printed material laminated to a triple layer woven fabric which is then laminated to a dewatering fabric where the fine synthetic batt fibers of the dewatering fabric are preferably needled into the dewatering fabric and through the bottom layer of the triple layer woven fabric of the web contacting layer after the web contacting layer has been laminated to the dewatering fabric. The batting thus reinforces the lamination between the web-contacting layer and dewatering fabric layer to provide for a more durable laminated structuring fabric. With the batting only being needled through the bottom woven layer of the web contacting layer, there exists a batt-free top woven layer of the web contacting layer that is laminated with the extruded polymer netting or 3-D printed material. This batt free layer is porous to allow for water to leave the paper web and quickly penetrate through the web contacting layer, into the dewatering fabric layer, and finally through the dewatering fabric layer into the suction pressure roll and save-all pan as the web is pressed in the press nip. Without being bound by theory, rapid water removal at the press helps provide for even water removal from the web and thus more uniform paper physical properties.

(17) In preferred embodiment, the structuring fabric 13 has a compressible web contacting layer such that under compression in the first and second press nip, the web contacting layer deforms and becomes nearly coplaner but still above the plane of the supporting layer. The compressible web contacting layer increases the area of the paper web that undergoes compression in the press nips thereby increasing water removal, as described in U.S. patent application Ser. No. 16/881,219, the contents of which are incorporated herein by reference in its entirety.

(18) Dewatering fabric 5 runs in an endless loop through a high pressure needle or fan shower 101, flooding shower 15A and a uhle box 16A to remove water and clean the fabric. Guide roll 17 keeps the fabric from varying in movement in the cross machine direction and stretch roll 18 maintains proper fabric tension. If the structuring fabric 13 contains a dewatering fabric layer, the web travels on structuring fabric 13 after leaving the press nip through a dewatering device comprised of a steam box 10A and a vacuum device 19. In other exemplary embodiments, the dewatering device may be omitted. The vacuum device 19 may be, for example, a vacuum roll, vacuum box, or vacuum shoe.

(19) If the structuring fabric does not contain a dewatering fabric layer, then hot air rather than steam can be applied. In this case, the steam box 10A may be replaced with a hot air impingement device/hood and the vacuum device 19 may be replaced with an exhaust duct. The hot air impingement device/hood blows hot air through the web and structuring fabric 13 into the exhaust duct. In exemplary embodiments, the source air for the hot air may be exhaust air from the hot air impingement hood over the Yankee dryer, or fresh air can be heated using combusted natural gas. A portion of this air can be recirculated, reheated, and reused to minimize energy usage.

(20) Using a hot air impingement device/hood with a vacuum device 19 may be beneficial when using any of the structuring fabrics. Without being bound by theory, it is believed that this combination may improve molding of the sheet into the structuring fabric over the conventional methods mentioned as both the air impingement and vacuum would provide maximum force to push and pull the web into the fabric. Dewatering ability of this arrangement may or may not be improved.

(21) Then the structuring fabric 13 and web pass over a bowed roll 23 to prevent wrinkling of the structuring fabric, through a moisture scanner 100 and then enter the nip between a press element 21 and a steam cylinder 22. A steambox 10B can be positioned over press element 21. The scanner 100 measures the cross direction moisture profile of the web and controls zones in any of the steamboxes to preferentially dry areas of the web to maintain an even moisture profile. The press element 21 may be any of the aforementioned pressing devices but is preferably a suction pressure roll or shoe press. Excess water is doctored from the press element 21 using a single, double, or triple doctor 7C into pan 14C.

(22) In a preferred embodiment, the structuring fabric 13 has a structure that is the same as or similar to that described in U.S. Pat. No. 10,208,426, including a netting layer laminated to a multilayer woven and backside batting that is needle punched into the fabric. The hot air emitted by the steam box 10A is then pushed through the paper web into the vacuum box 19, which is located on the backside of the structuring fabric 13 (the side with the multilayer woven and needle punched batting). Without being bound by theory, it is believed that passing the paper web on the structuring fabric 13 with such a configuration first through a dewatering section made up of the steambox 10A and vacuum device 19 and then to a press section made up of the press element 21 and steam box 10B results in better imprinting of the netting onto the paper web. This configuration also enables a third dewatering step on the same belt without removing the paper web from the belt before transferring the structured paper to the Yankee drier surface.

(23) The web is transferred to the steam heated cylinder 22, which is coated with chemicals via a chemical shower 50 that improves web adhesion to the steam heated cylinder, improves heat transfer through the web, and assists in web removal at the creping doctor 26. The chemicals are constantly applied using a chemical shower or sprayboom 50, while excess is removed using a cleaning doctor blade 27. An additional “cut off” blade 25 is intermittently utilized to allow for blade changes for the creping and cleaning position. The web is dried by the steam heated cylinder 23 along with an installed hot air impingement hood 24 from a solids content of roughly 50% to a solids content of roughly 97.5%.

(24) The web is removed from the steam heated cylinder 22 using a steel or ceramic doctor blade 26 with a pocket angle of 90 degrees at the creping doctor. At this stage, the web properties are influenced by the creping action occurring at the creping doctor. A larger creping pocket angle increases the frequency and fineness of the crepe bars imparted to the web's first exterior surface, which improves surface smoothness. The use of a ceramic doctor blade is preferred because it allows for a fine crepe bar pattern to be imparted to the web for a longer duration of time compared to a steel or bimetal blade. The creping action imparted to the sheet at the blade also improves web flexibility, and the creping action is enhanced as the web adherence to the dryer is increased. The creping force is primarily influenced by the chemistry applied to the steam heated cylinder, the % web contact with the cylinder surface, which is a result of the pattern of the structured fabric, and the percent web solids upon creping.

(25) The web now optionally travels through a set of calendars 60 running, for example, 15% slower than the steam heated cylinder. The action of calendaring improves sheet smoothness but results in lower bulk softness by reducing overall web thickness. The amount of calendaring can be influenced by the attributes needed in the finished product. For example, a low sheet count, 2-ply, rolled sanitary tissue product will need less calendaring than the same roll of 2-ply sanitary product at a higher sheet count and the same roll diameter and firmness. The thickness of the web may need to be reduced using calendaring to allow for more sheets to fit on a roll of sanitary tissue, given limitations to roll diameter and firmness. After calendaring, the web travels through a scanner 160 that measures cross direction basis weight and moisture, and controls actuators inside the headbox to control dilution water to even out the basis weight profile. The web is then reeled using a reel drum 70 into a parent roll 80.

(26) The parent roll 70 can be converted into 1 or 2-ply rolled sanitary or towel products or 1, 2, or 3 ply folded facial tissue products.

(27) In exemplary embodiments, instead of adhering the web to a steam heated cylinder, the web can be removed from the structured fabric to directly proceed to the calendaring section. Any variety of methods can be used to remove the web from the structured fabric. For example, positive air pressure from the press element 21 may be used to transfer the sheet from the structured fabric onto a vacuum roll. The vacuum roll contains a vacuum zone and a zone with positive air pressure used to release the sheet from the roll and allow it to proceed through the calendars. A tube threader system may be used to thread the sheet from this vacuum roll through the calendars and reel drum after a web break. A similar system may be used to thread after a break from the creping doctor when a steam heated cylinder is utilized.

(28) After transferring the web to the steam heated cylinder 22, the structuring fabric 13 travels in an endless loop through high pressure needle or fan showers 102 and 103, flooding shower 15B, and uhle boxes 16B for fabric cleaning and dewatering. A shower 200 that applies a release chemical such as petroleum oil can be used to aid in later paper web transfer to the drying cylinder. Stretch roll 30 is utilized to maintain fabric tension, and guide roll 31 is utilized to prevent the fabric from varying in movement in the cross machine direction.

(29) FIG. 2 shows a block diagram of a papermaking machine, generally designated by reference number 100, according to another exemplary embodiment of the present invention. The papermaking machine 100 varies from the machine shown in FIG. 1 in the geometry of the press section. In this case, the structuring fabric 113 has a longer wrap around vacuum element 112 to increase the dwell time and thus dewatering of the web as it travels on the structuring fabric across vacuum element 112. The vacuum element 112 may have more than one vacuum zone. In exemplary embodiments, a vacuum zone at the nip with press element 111 may have an applied vacuum level that is different from that of vacuum zones outside the nip.

(30) More specifically, the papermaking machine 100 includes a first exterior layer fan pump 128, a core layer fan pump 129, and a second exterior layer fan pump 130. The fan pumps 128, 129, 130 move a dilute slurry of fiber and chemicals to a triple layer headbox 103 which deposits the slurry into a nip formed by a forming roll 102, a breast roll 140, an outside forming fabric 104 and an inside dewatering fabric 105.

(31) The outer forming fabric is preferably a triple layer forming fabric, such as, for example, the T-Star AJ-494 Forming Fabric provided by Asten Johnson (4399 Corporate Road, Charleston, S.C., USA 29405), but can be any other forming fabric design. Forming fabric 104 runs in an endless loop around a plurality of guide rolls 108 to return back to the breast roll 140.

(32) The forming roll 102 is preferably a solid rubber covered roll, but can be any other type of forming roll, such as an impermeable or permeable roll with an internal vacuum box, and may be covered with a smooth or textured material. The forming roll cover may be made from a material selected from, but not limited to rubber, or polyurethane. The cover may also have a pattern of filaments made of metal or polymer to create a texture.

(33) Excess water may be doctored from the forming roll using a single, double, or triple doctor 107A to aid in removing water that may be wringing the roll and rewetting the web. The water is captured in a pan 114A and directed off the machine to prevent stock and water buildup on the machine frame, which may otherwise lead to drips and holes in the tissue webs and subsequent sheet-breaks and lost operating time.

(34) The dewatering fabric 105 is typically comprised of large polymer monofilaments or multi-filamentous yarns, needled with fine synthetic batt fibers to form a smooth surface for even web pressing. However, any type of dewatering fabric can be used, such as, for example, the fabric shown in FIG. 14A of U.S. Pat. No. 7,476,294, the contents of which are incorporated herein by reference in their entirety, where other absorbent porous materials are incorporated. Another example of a fabric structure that may be used as the dewatering fabric 105 is described in U.S. Pat. No. 10,208,426, and includes nylon woven monofilaments, laminated to extruded polymer netting for compression resistance, and then needle punched with batt fiber on the surface and through the structure.

(35) After separation of the forming and dewatering fabric, a vacuum transfer box is used to assist in nascent web adherence to the dewatering fabric 105. The dewatering fabric 105 then travels with the web across a dewatering suction device comprised of suction roll 109 and steam box 110. In other exemplary embodiments, the dewatering suction device may be omitted. The steambox applies approximately 0.1-1.0 ton of steam per ton of paper to heat the water in the web and lower the viscosity to improve water removal through the suction roll 109. Other dewatering devices known in the art can be used, such as, for example, a vacuum box or suction shoe, which are both non-rotating water removal devices and therefore not preferred as they can cause wear to the dewatering fabric.

(36) The web travels across the dewatering device and into the press section comprised of a press element 111, suction element 112, the dewatering fabric 105, and structuring fabric 113. Press element 111 is preferably an extended nip press, such as, for example, a shoe press or belt press. Extended nip presses extend the time that the paper web remains in the press nip. The amount of water removed in the nip is proportional to the magnitude and the duration of the pressure applied to the paper web. Using an extended nip, the manufacturer can utilize less pressure to achieve the same amount of dewatering while maintaining web bulk and preserving fabric life. Examples of a shoe press include the Advantage ViscoNip Press from Valmet (Keilasatama 5/PO Box 11 FI-02150 ESPOO, FINLAND), and the NipcoFlex T from Voith (St. Poltener Straße 43 89522 Heidenheim Germany). FIG. 16 of U.S. Pat. No. 7,351,307, the contents of which are incorporated herein by reference in their entirety, shows an example of a suitable belt press. In exemplary embodiments, the shoe press cover may be made of rubber, polyurethane, or other material with through drilled holes, blind drilled holes, grooves, or a combination thereof. Suction element 112 is preferably a suction pressure roll which contains a rubber, polyurethane, or other material cover with through drilled holes, blind drilled holes, grooves, or a combination thereof. Other dewatering devices known in the art can be used, such as, for example, a vacuum box or suction shoe (pickup shoe), which are both non-rotating water removal devices and therefore not preferred as they can cause wear to the structuring fabric. The press section may instead include conventional plain press rolls with a narrow nip width and high nip intensity, or capillary rolls (as described in U.S. Pat. No. 5,701,682, the contents of which are incorporated herein by reference in their entirety), or a combination thereof, although this is not preferred because the web would lose bulk and quality. In an exemplary embodiment, a machine direction dominated pattern on the structuring fabric lines up opposite the grooves on the suction pressure roll for enhanced water removal. As used herein, the term narrow nip width is intended to mean a nip width of less than about 9 cm or from about 4 cm to about 8 cm or less than about 8 cm, and high nip intensity is intended to mean a nip intensity greater than about 5,000 kN/m2 or from about 6,000 to about 12,000 kN/m2 or greater than about 6,000 kN/m2.

(37) The structuring fabric 113 can be of any type described in the background section of this patent application, such as a woven fabric, a woven fabric with an overlaid polymer, welded strips of polymeric material or extruded sheets of polymer which are etched by punching, drilling, or laser drilling, woven fabrics laminated with a 3-D printed web contacting or structuring layer, or a structuring fabric made entirely from 3-D printed material As the web travels on the dewatering fabric 105 through the first press nip, the dewatering fabric 105 and the structuring fabric 113 are subjected to compression and expansion, thereby uptaking and removing water from both sides of the web. Vacuum applied by the suction element 112 also draws the water into the structuring fabric 113 and pulls the fiber into the structuring fabric 113 to develop texture and bulk in the web. Water removed at vacuum element 112 is deposited in pan 114B, and excess water that may be wringing the roll and rewetting the web is doctored from the element using a single, double, or triple doctor 107B.

(38) In preferred embodiments the structuring fabric is a laminated fabric with a web-contacting layer made from extruded polymer netting or 3-D printed material laminated to a woven fabric or a dewatering fabric as described in U.S. Pat. No. 10,208,426. In another preferred embodiment the structuring fabric has a web contacting layer comprising extruded polymer netting or 3-D printed material laminated to a triple layer woven fabric which is then laminated to a dewatering fabric where the fine synthetic batt fibers of the dewatering fabric are preferably needled into the dewatering fabric and through the bottom layer of the triple layer woven fabric of the web contacting layer after the web contacting layer has been laminated to the dewatering fabric. The batting thus reinforces the lamination between the web-contacting layer and dewatering fabric layer to provide for a more durable laminated structuring fabric. With the batting only being needled through the bottom woven layer of the web contacting layer, there exists a batt-free top woven layer of the web contacting layer that is laminated with the extruded polymer netting or 3-D printed material. This batt free layer is porous to allow for water to leave the paper web and quickly penetrate through the web contacting layer, into the dewatering fabric layer, and finally through the dewatering fabric layer into the suction pressure roll and save-all pan as the web is pressed in the press nip. Without being bound by theory, rapid water removal at the press helps provide for even water removal from the web and thus more uniform paper physical properties.

(39) In preferred embodiment, the structuring fabric 113 has a compressible web contacting layer such that under compression in the first and second press nip, the web contacting layer deforms and becomes nearly coplaner but still above the plane of the supporting layer. The compressible web contacting layer increases the area of the paper web that undergoes compression in the press nips thereby increasing water removal, as described in U.S. patent application Ser. No. 16/881,219, the contents of which are incorporated herein by reference in its entirety.

(40) Dewatering fabric 105 runs in an endless loop through a high pressure needle or fan shower 1101, flooding shower 115A and a uhle box 116A to remove water and clean the fabric. Guide roll 117 keeps the fabric from varying in movement in the cross machine direction and stretch roll 118 maintains proper fabric tension. If the structuring fabric 113 contains a dewatering fabric layer, the web travels on structuring fabric 113 after leaving the press nip through a dewatering device comprised of a steam box 110A and a vacuum device 119. In other exemplary embodiments, the dewatering device may be omitted. The vacuum device 119 may be, for example, a vacuum roll, vacuum box, or vacuum shoe.

(41) If the structuring fabric does not contain a dewatering fabric layer, then hot air rather than steam can be applied. In this case, the steam box 110A may be replaced with a hot air impingement device/hood and the vacuum device 119 may be replaced with an exhaust duct. The hot air impingement device/hood blows hot air through the web and structuring fabric 113 into the exhaust duct. In exemplary embodiments, the source air for the hot air may be exhaust air from the hot air impingement hood over the Yankee dryer, or fresh air can be heated using combusted natural gas. A portion of this air can be recirculated, reheated, and reused to minimize energy usage.

(42) Using a hot air impingement device/hood with a vacuum device 119 may be beneficial when using any of the structuring fabrics. Without being bound by theory, it is believed that this combination may improve molding of the sheet into the structuring fabric over the conventional methods mentioned as both the air impingement and vacuum would provide maximum force to push and pull the web into the fabric. Dewatering ability of this arrangement may or may not be improved.

(43) Then the structuring fabric 113 and web pass may over a bowed roll to prevent wrinkling of the structuring fabric, through a moisture scanner and then enter the nip between a press element 121 and a steam cylinder 122. A steambox 110B can be positioned over press element 121. The scanner measures the cross direction moisture profile of the web and controls zones in any of the steamboxes to preferentially dry areas of the web to maintain an even moisture profile. The press element 121 may be any of the aforementioned pressing devices but is preferably a suction pressure roll or shoe press. Excess water is doctored from the press element 121 using a single, double, or triple doctor into pan 114C.

(44) In a preferred embodiment, the structuring fabric 113 has a structure that is the same as or similar to that described in U.S. Pat. No. 10,208,426, including a netting layer laminated to a multilayer woven and backside batting that is needle punched into the fabric. The hot air emitted by the steam box 10A is then pushed through the paper web into the vacuum box 119, which is located on the backside of the structuring fabric 113 (the side with the multilayer woven and needle punched batting). Without being bound by theory, it is believed that passing the paper web on the structuring fabric 113 with such a configuration first through a dewatering section made up of the steambox 110A and vacuum device 119 and then to a press section made up of the press element 121 and steam box 110B results in better imprinting of the netting onto the paper web. This configuration also enables a third dewatering step on the same belt without removing the paper web from the belt before transferring the structured paper to the Yankee drier surface.

(45) The web is transferred to the steam heated cylinder 122, which is coated with chemicals via a chemical shower that improves web adhesion to the steam heated cylinder, improves heat transfer through the web, and assists in web removal at the creping doctor 126. The chemicals are constantly applied using a chemical shower or sprayboom, while excess is removed using a cleaning doctor blade 127. An additional “cut off” blade 125 is intermittently utilized to allow for blade changes for the creping and cleaning position. The web is dried by the steam heated cylinder 122 along with an installed hot air impingement hood 124 from a solids content of roughly 50% to a solids content of roughly 97.5%.

(46) The web is removed from the steam heated cylinder ‘22 using a steel or ceramic doctor blade 126 with a pocket angle of 90 degrees at the creping doctor. At this stage, the web properties are influenced by the creping action occurring at the creping doctor. A larger creping pocket angle increases the frequency and fineness of the crepe bars imparted to the web's first exterior surface, which improves surface smoothness. The use of a ceramic doctor blade is preferred because it allows for a fine crepe bar pattern to be imparted to the web for a longer duration of time compared to a steel or bimetal blade. The creping action imparted to the sheet at the blade also improves web flexibility, and the creping action is enhanced as the web adherence to the dryer is increased. The creping force is primarily influenced by the chemistry applied to the steam heated cylinder, the % web contact with the cylinder surface, which is a result of the pattern of the structured fabric, and the percent web solids upon creping.

(47) The web now optionally travels through a set of calendars running, for example, 15% slower than the steam heated cylinder. The action of calendaring improves sheet smoothness but results in lower bulk softness by reducing overall web thickness. The amount of calendaring can be influenced by the attributes needed in the finished product. For example, a low sheet count, 2-ply, rolled sanitary tissue product will need less calendaring than the same roll of 2-ply sanitary product at a higher sheet count and the same roll diameter and firmness. The thickness of the web may need to be reduced using calendaring to allow for more sheets to fit on a roll of sanitary tissue, given limitations to roll diameter and firmness. After calendaring, the web travels through a scanner that measures cross direction basis weight and moisture, and controls actuators inside the headbox to control dilution water to even out the basis weight profile. The web is then reeled using a reel drum into a parent roll.

(48) The parent roll can be converted into 1 or 2-ply rolled sanitary or towel products or 1, 2, or 3 ply folded facial tissue products.

(49) In exemplary embodiments, instead of adhering the web to a steam heated cylinder, the web can be removed from the structured fabric to directly proceed to the calendaring section. Any variety of methods can be used to remove the web from the structured fabric. For example, positive air pressure from the press element 121 may be used to transfer the sheet from the structured fabric onto a vacuum roll. The vacuum roll contains a vacuum zone and a zone with positive air pressure used to release the sheet from the roll and allow it to proceed through the calendars. A tube threader system may be used to thread the sheet from this vacuum roll through the calendars and reel drum after a web break. A similar system may be used to thread after a break from the creping doctor when a steam heated cylinder is utilized.

(50) After transferring the web to the steam heated cylinder 122, the structuring fabric 113 travels in an endless loop through high pressure needle or fan showers 1102 and 1103, flooding shower 115B, and uhle boxes 116B for fabric cleaning and dewatering. A shower that applies a release chemical such as petroleum oil can be used to aid in later paper web transfer to the drying cylinder. Stretch roll 130 is utilized to maintain fabric tension, and guide roll 131 is utilized to prevent the fabric from varying in movement in the cross machine direction.

(51) In exemplary embodiments, during the papermaking process, the paper web being conveyed on a structuring fabric is transferred to the Yankee dryer at a nip formed between the Yanke dryer and a pressure roll. During this transfer (referred to herein as “soft nip transfer”), the web contacting surface (in some cases, extruded polymer netting) of the structuring fabric is compressed in the nip between the pressure roll and Yankee dryer such that the top plane of a first element of the structuring fabric is substantially in the same plane as the top plane of a second element of the structuring fabric. More specifically, the soft nip transfer results in compression and deflection of the web contacting layer of the structuring fabric, which in turn results in a higher contact area between the web and the structuring fabric and between the web and Yankee dryer.

(52) A composite or laminated structuring fabric according to an exemplary embodiment of the present invention includes a web contacting layer with a top plane that has a contact area with the Yankee dryer between 15% to 45% in the uncompressed state but increases to 30% to 60% contact area in the compressed state when under 200 to 300 PLI load, which is the typical load range that exists in the nip between the pressure roll and Yankee dryer. In this regard, the top plane of first elements of the structuring fabric is substantially in the same plane as the top plane of second elements of the structuring fabric when the top plane of the web contacting layer has a contact area with the Yankee dryer between 30% to 60%. The contact area increases as the first elements are compressed into the same plane as the second elements. It should be appreciated that one of ordinary skill in the art would understand that the paper web is molded into the web contacting layer of the structuring fabric. Thus, one of ordinary skill in the art would also understand that the term “contact area” as used herein in the context of the structuring fabric is actually the contact area of the structuring fabric with the paper web molded into the web contacting layer of the structuring fabric.

(53) FIG. 3 is a micrograph showing a cross-section of a web contacting layer, generally designated by reference number 1000, of a structuring fabric according to an exemplary embodiment of the present invention. The web contacting layer 1000 is preferably made of an extruded polymer netting having first elements 1010 extending in the machine direction and second elements 1020 extending the cross direction so as to form openings within the web contacting layer 1000. As shown in FIG. 3, the first elements 1010 extend above the second elements 1020 so as to form ridges extending in the machine direction. The second elements 1020 extending in the cross direction may be referred to herein as “mid-rib” elements.

(54) In exemplary embodiments, the distance (D) between the top plane of the ridges of the first elements 1010 and the top plane of the second elements 1020 is greater than 200 microns. As discussed, during the papermaking process, the paper web being conveyed on the composite structuring fabric is transferred to the Yankee dryer at a nip formed between the Yanke dryer and a pressure roll. During this soft nip transfer, the extruded polymer netting of the composite structuring fabric is compressed and deflected in the nip between the pressure roll and Yankee dryer such that the top plane of the first element 1010 is substantially in the same plane as the top plane of the second element 1020. In an exemplary embodiment, the top plane of the web contacting layer 1000 has a contact area with the Yankee dryer between 15% to 45% in the uncompressed state but increases to 30 to 60% contact area in the compressed state when under 200 to 300 PLI load. In this regard, the top plane of the first elements 1010 of the structuring fabric 1000 is substantially in the same plane as the top plane of the second elements 1020 of the structuring fabric 1000 when the top plane of the web contacting layer of the structuring fabric 1000 has a contact area with the Yankee dryer between 30% to 60%. The contact area increases as the first elements 1010 are compressed into the same plane as the second elements 1020. It should be appreciated that the systems and processes described herein are not limited to the use of this exemplary structuring fabric, and other structuring fabrics may be used to achieve the objects and advantages of the present invention. Further, it should be appreciated that the structuring fabric may be compressed and deflected in any one of the nips within the papermaking machine so as to result in a soft nip transfer.

(55) FIGS. 4 and 5 are micrographs showing a structuring fabric according to an exemplary embodiment of the present invention having a 28% surface contact area with the Yankee dryer leading into the nip (FIG. 4) and a 54% surface contact area with the Yankee dryer in the nip (FIG. 5). FIG. 6 is a photograph showing a bath tissue product according to an exemplary embodiment of the present invention resulting from the soft nip transfer shown in FIGS. 4 and 5. In FIG. 6, cross-direction ridges 600 can be seen on the surface of the tissue product, resulting from the compression and deflection of the mid-rib elements of the structuring fabric.

(56) Now that embodiments of the present invention have been shown and described in detail, various modifications and improvements thereon will become readily apparent to those skilled in the art. Accordingly, the spirit and scope of the present invention is to be construed broadly and not limited by the foregoing specification.