US20090139673A1 - Sheet formation process and wet end to produce a pulp web - Google Patents

Sheet formation process and wet end to produce a pulp web Download PDF

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Publication number
US20090139673A1
US20090139673A1 US12/313,091 US31309108A US2009139673A1 US 20090139673 A1 US20090139673 A1 US 20090139673A1 US 31309108 A US31309108 A US 31309108A US 2009139673 A1 US2009139673 A1 US 2009139673A1
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United States
Prior art keywords
fluid
wet end
running direction
machine running
wire
Prior art date
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Abandoned
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US12/313,091
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English (en)
Inventor
Petra Resch
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Andritz AG
Original Assignee
Andritz AG
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Filing date
Publication date
Application filed by Andritz AG filed Critical Andritz AG
Assigned to ANDRITZ AG reassignment ANDRITZ AG ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: RESCH, PETR
Assigned to ANDRITZ AG reassignment ANDRITZ AG ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: RESCH, PETRA
Publication of US20090139673A1 publication Critical patent/US20090139673A1/en
Abandoned legal-status Critical Current

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    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F1/00—Wet end of machines for making continuous webs of paper
    • D21F1/02—Head boxes of Fourdrinier machines
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F1/00—Wet end of machines for making continuous webs of paper
    • D21F1/02—Head boxes of Fourdrinier machines
    • D21F1/028—Details of the nozzle section
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F1/00—Wet end of machines for making continuous webs of paper
    • D21F1/56—Deckle frame arrangements
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F9/00—Complete machines for making continuous webs of paper
    • D21F9/02—Complete machines for making continuous webs of paper of the Fourdrinier type

Definitions

  • the present invention concerns a sheet formation process to produce a pulp web with improved fibre orientation in a paper or board machine, as well as an appropriate wet end for implementing the sheet formation process.
  • a pulp suspension is applied to a wire with the aid of a headbox.
  • the headbox comprises a distributing device to distribute the pulp suspension over the machine width, a turbulence block made up of a large number of turbulence tubes, and a headbox nozzle.
  • the pulp suspension jet impinges onto the wire as evenly as possible over the entire machine width.
  • the jet from the headbox broadens, however, after exiting from the headbox nozzle, and there is further broadening of the jet after the open jet hits the wire.
  • a wire edge limitation is needed to guide the open jet and the pulp suspension onto the wire. Without the wire edge limitation the suspension would run off the wire at the sides, which would cause a drop in the basis weight and disrupt the fibre orientation in the areas at the edge of the web.
  • the wire edge limitation also has undesirable effects.
  • the fibre orientation is disrupted due to edge friction between the lateral headbox nozzle wall or wire edge limitation and the pulp suspension, and an uneven speed profile develops in the suspension, with a higher speed in the middle of the wire in running direction than at the edges.
  • the wire edge limitation creates a reflected wave towards the center of the wire when the suspension hits the wire edge limitation. This undesirable effect is mitigated by wire edge limitations that widen in the machine running direction.
  • the pulp suspension flows into the areas laid open by this widening, which results in formation of a pulp mat with a thinner edge.
  • EP 1 619 298 A2 discloses a headbox in which the turbulence channels at the edge of the turbulence generator are separated from the remaining turbulence generating area. These lateral turbulence channels each have feed pipes for an edge flow that can be used to influence the fibre orientation profile.
  • EP 0 857 816 B1 describes a headbox with an integrated edge feed arrangement in the vicinity of the turbulence block. Infeed of an edge flow in the turbulence block, however has the disadvantage that very large quantities of edge flow must be supplied in order to be able to compensate or reduce subsequent edge friction effects. This considerable overdosing leads to disruption of the flow before the jet exists from the headbox, and thus to disruption of the fibre orientation.
  • the object of the invention is to provide an improved sheet formation process and a paper or board machine wet end suitable for this process that circumvents the above mentioned disadvantages, thus reducing disruption of fibre orientation and forming a fibre mat with improved basis weight distribution over the entire machine width.
  • This object is achieved by a sheet formation process in which a fluid is added to the pulp suspension from the side through openings located after a turbulence block in a headbox at the machine wet end. This leads to improved suspension guiding and to a reduction or compensation of edge friction. If the wire edge limitation widens in addition, the areas laid open by this widening fill up with the fluid and thus prevent the suspension from running off the wire in these edge areas.
  • the fluid used here is preferably white water, which permits a particularly simple process flow because a large quantity of white water is produced at the wet end anyway.
  • the fluid used is a pulp suspension that can also have a lower or higher consistency than the pulp suspension fed to the headbox distributor. Due to this additional input of pulp, the differences in basis weight across the machine running direction can be compensated more effectively. With a wire edge limitation that widens in machine running direction, the space formed by widening fills up with pulp suspension because of this additional input of pulp, thus achieving a uniform suspension height on the wire. This favors uniform basis weight distribution over the entire width of the pulp web.
  • the fluid used can also be a gas, particularly air. This can also achieve a reduction in edge friction without additional liquid having to be added to the pulp mat forming.
  • the fluid can be added in the machine running direction at several points located one after the other, where the fluid can be added at different flow speeds or in different quantities at the individual points. It is preferable if the quantity and/or the flow speed of the fluid increases from one addition point to the next in the machine running direction because the pulp suspension thickens as a result of the dewatering process, thus the effort required to compensate edge friction increases.
  • the invention is also directed to a wet end for sheet formation, where feed channels with openings for feeding a fluid to the pulp suspension are provided in the wire edge limitation and/or headbox nozzle after a turbulence block.
  • feed channels with openings for feeding a fluid to the pulp suspension are provided in the wire edge limitation and/or headbox nozzle after a turbulence block.
  • the fluid exiting from the openings reduces edge friction and improves sheet formation.
  • the openings can be located either in a side wall of the headbox nozzle or in a side wall of the wire edge limitation. Addition of fluid in the headbox nozzle has the advantage that existing wire edge limitations do not have to be modified, whereas addition via the wire edge limitation allows improved minimizing of edge friction until final formation of the sheet.
  • the feed channels end at the side wall, largely in parallel with the machine running direction. This has the advantage that the fluid flows largely in machine running direction.
  • the side wall has at least one recess after the opening, which recess has a narrowing cross-section in the machine running direction, where the side wall serves as a guiding surface for the fluid added in the area of the recess. Due to this special design of the side wall, the fluid is added to the pulp suspension roughly in machine running direction and formation of a friction-reducing fluid film is enhanced.
  • the wet end In a favorable embodiment of the wet end, several exit openings are provided, preferably one after the other viewed in the machine running direction.
  • FIG. 1 shows a schematic diagram of a wet end according to the invention
  • FIG. 2 shows a schematic diagram of a further variant of a wet end according to the invention
  • FIG. 3 shows a schematic side view of FIG. 1 ;
  • FIG. 4 shows a perspective detailed view of FIG. 1 .
  • the configuration shown in FIG. 1 includes a headbox 1 consisting of a distributor 2 , a turbulence block 3 , which comprises a large number of turbulence tubes 4 , and a subsequent headbox nozzle 5 through which the pulp suspension fed in by the distributor 2 is discharged onto a wire 6 .
  • the machine running direction is indicated by an arrow 15 .
  • a wire edge limitation 7 that prevents the pulp suspension that impinges onto the wire 6 from running off the wire 6 at the sides.
  • the openings 9 of feed channels 10 are located in the side wall 8 of the wire edge limitation 7 .
  • a fluid for example water, dilution water or pulp suspension, air, or a mixture of these components is added through these feed channels 10 .
  • edge friction between the pulp suspension and the side wall 8 of the wire edge limitation 7 is reduced because the fluid forms a boundary film between the suspension and the side wall 8 .
  • the fluid is largely introduced through nozzles in the machine running direction, where the flow speed of the fluid is greater than the speed of the pulp suspension on the wire.
  • the openings 9 in the side wall 8 of the wire edge limitation 7 are located in recesses 11 . Due to these recesses 11 the fluid is introduced through nozzles as parallel as possible to the machine running direction between the side wall 8 of the wire edge limitation 7 and the pulp suspension coming out of the headbox 1 .
  • FIG. 2 illustrates a further embodiment of the invention, where the reference figures correspond to those used in FIG. 1 .
  • the fluid is added via feed channels 10 ′ through openings 9 ′ in the side wall 8 ′, thus enhancing fluid feed in the machine running direction.
  • FIG. 3 shows a side view of FIG. 1 , where the wire 6 that is deflected by a breast roll 12 under the headbox 1 can be seen particularly clearly.
  • the pulp suspension leaving the headbox nozzle 5 hits the wire 6 at the impingement point 13 .
  • the opening 9 and the recess 1 in the side wall 8 of the wire edge limitation 7 are indicated.
  • FIG. 4 a perspective detailed view of FIG. 1 is provided and clearly shows the shape of the recess 11 in the side wall 8 .
  • the pulp suspension exists here from the nozzle opening 14 of the headbox nozzle 5 and hits the wire 6 at the impingement point 13 .
  • the fluid exits from the opening 9 .
  • the opening 9 is arranged vertically to the machine running direction in the recess 11 of the side wall 8 and in a slot shape.
  • the recess 11 cross-section narrows continuously in the machine running direction.
  • a pulp suspension is fed through the distributor 2 to the headbox 1 .
  • part of the suspension can also be removed through a return flow 2 ′.
  • the pulp suspension flows in the headbox 1 through a large number of turbulence pipes 4 into the headbox nuzzle 5 .
  • the pulp suspension hits the wire 6 at the impingement point 13 .
  • a fluid to alter the speed profile of the pulp suspension is injected through feed channels 10 , 10 ′ in the wire edge limitation 7 or the headbox nozzle 5 .
  • the flow speed of the fluid in the machine running direction is preferably higher than the speed of the pulp suspension, and also has lower viscosity and consistency than the pulp suspension, if applicable. Due to the higher flow speed of the fluid, the pulp suspension in the edge zones is accelerated in machine running direction. As a result, an even speed profile is formed over the entire width of the pulp suspension.
  • the embodiments shown in the drawings merely show some of the embodiment of the invention.
  • the invention also relates to other embodiments, e.g., injecting a fluid through the side wall 8 ′ of the headbox nozzle 5 and through the side wall 8 of the wire edge limitation 7 .
  • injecting a fluid through the side wall 8 ′ of the headbox nozzle 5 and through the side wall 8 of the wire edge limitation 7 .
  • several openings 9 , 9 ′ arranged in the machine running direction.
  • the fluid can be added at different speeds and/or in different quantities through each opening. It is an advantage if the speed of the fluid added through the individual openings 9 , 9 ′ increases in the machine running direction because the pulp suspension thickens on the wire 6 due to the dewatering process, thus requiring greater effort to compensate edge friction.
US12/313,091 2007-11-19 2008-11-17 Sheet formation process and wet end to produce a pulp web Abandoned US20090139673A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
ATA1869/2007 2007-11-19
AT0186907A AT505931B8 (de) 2007-11-19 2007-11-19 Blattbildungsverfahren und nasspartie zur herstellung einer faserstoffbahn

Publications (1)

Publication Number Publication Date
US20090139673A1 true US20090139673A1 (en) 2009-06-04

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Family Applications (1)

Application Number Title Priority Date Filing Date
US12/313,091 Abandoned US20090139673A1 (en) 2007-11-19 2008-11-17 Sheet formation process and wet end to produce a pulp web

Country Status (4)

Country Link
US (1) US20090139673A1 (de)
EP (1) EP2060675A3 (de)
JP (1) JP2009127186A (de)
AT (1) AT505931B8 (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110016830A (zh) * 2019-04-16 2019-07-16 华南理工大学 一种斜网成型器用的非接触式密封装置及方法
US10513825B2 (en) 2017-09-18 2019-12-24 Ahmed Ibrahim Paper manufacturing system

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FI20105026A (fi) * 2010-01-15 2011-07-16 Metso Paper Inc Laite kuiturainakoneen rainanmuodostusosaa varten
CN102071588B (zh) * 2010-11-11 2012-08-22 华南理工大学 流浆箱的互补式布浆器
CN103046418A (zh) * 2012-12-20 2013-04-17 华南理工大学 一种新月型双层流浆箱
KR101695542B1 (ko) * 2015-04-28 2017-01-11 추경연 제지 장치용 에지 세이버

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3715551A1 (de) * 1987-05-09 1988-12-01 Voith Gmbh J M Verfahren zum verringern des flatterns der bahnraender einer papierbahn sowie papiermaschine zum durchfuehren des verfahrens
JPH03249297A (ja) * 1990-02-26 1991-11-07 Mitsubishi Heavy Ind Ltd 抄紙機ヘッドボックスの流向調整方法
US5045154A (en) * 1990-06-28 1991-09-03 Baluha Mark R Conveyor edge product containing device for paper making machinery
FI115645B (fi) 1997-01-14 2005-06-15 Metso Paper Inc Paperikoneen perälaatikko, jossa on reunasyöttöjärjestelyt
FI115473B (fi) * 2004-03-25 2005-05-13 Process Flow Ltd Oy Laite ja menetelmä paperikoneessa sekä paperikone
DE102004035303A1 (de) 2004-07-21 2006-02-16 Voith Paper Patent Gmbh Stoffauflauf für eine Maschine zur Herstellung einer Faserstoffbahn, insbesondere einer Papier- oder Kartonbahn

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10513825B2 (en) 2017-09-18 2019-12-24 Ahmed Ibrahim Paper manufacturing system
CN110016830A (zh) * 2019-04-16 2019-07-16 华南理工大学 一种斜网成型器用的非接触式密封装置及方法

Also Published As

Publication number Publication date
AT505931B1 (de) 2009-05-15
EP2060675A3 (de) 2009-10-07
EP2060675A2 (de) 2009-05-20
AT505931B8 (de) 2009-06-15
AT505931A4 (de) 2009-05-15
JP2009127186A (ja) 2009-06-11

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AS Assignment

Owner name: ANDRITZ AG, AUSTRIA

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:RESCH, PETR;REEL/FRAME:021904/0148

Effective date: 20081114

AS Assignment

Owner name: ANDRITZ AG, AUSTRIA

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:RESCH, PETRA;REEL/FRAME:022044/0889

Effective date: 20081114

STCB Information on status: application discontinuation

Free format text: EXPRESSLY ABANDONED -- DURING EXAMINATION