WO2008000885A1 - Section de presse d'une machine à papier ou carton - Google Patents

Section de presse d'une machine à papier ou carton Download PDF

Info

Publication number
WO2008000885A1
WO2008000885A1 PCT/FI2007/000165 FI2007000165W WO2008000885A1 WO 2008000885 A1 WO2008000885 A1 WO 2008000885A1 FI 2007000165 W FI2007000165 W FI 2007000165W WO 2008000885 A1 WO2008000885 A1 WO 2008000885A1
Authority
WO
WIPO (PCT)
Prior art keywords
press
web
belt
counter
smoothing
Prior art date
Application number
PCT/FI2007/000165
Other languages
English (en)
Inventor
Kari RÄISÄNEN
Jorma Laapotti
Petter Honkalampi
Jussi JÄÄSKELÄINEN
Jari Savela
Original Assignee
Metso Paper, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Metso Paper, Inc. filed Critical Metso Paper, Inc.
Publication of WO2008000885A1 publication Critical patent/WO2008000885A1/fr

Links

Classifications

    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F3/00—Press section of machines for making continuous webs of paper
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F3/00—Press section of machines for making continuous webs of paper
    • D21F3/02—Wet presses
    • D21F3/0209—Wet presses with extended press nip
    • D21F3/0218—Shoe presses
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F3/00—Press section of machines for making continuous webs of paper
    • D21F3/02—Wet presses
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F3/00—Press section of machines for making continuous webs of paper
    • D21F3/02—Wet presses
    • D21F3/04—Arrangements thereof
    • D21F3/045—Arrangements thereof including at least one extended press nip
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21G—CALENDERS; ACCESSORIES FOR PAPER-MAKING MACHINES
    • D21G1/00—Calenders; Smoothing apparatus
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21G—CALENDERS; ACCESSORIES FOR PAPER-MAKING MACHINES
    • D21G1/00—Calenders; Smoothing apparatus
    • D21G1/006—Calenders; Smoothing apparatus with extended nips
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21G—CALENDERS; ACCESSORIES FOR PAPER-MAKING MACHINES
    • D21G1/00—Calenders; Smoothing apparatus
    • D21G1/0066—Calenders; Smoothing apparatus using a special calendering belt

Definitions

  • the present invention relates to a press section in a paper or board machine, comprising in combination at least one dewatering press nip and a smoothing press positioned downstream in terms of the web running direction.
  • the invention relates further to a smoothing press for the press section of a paper or board machine.
  • the press section of a paper or board machine has a duty of dewatering a wet fibrous web (dry content 15-23%) as effectively as possible, such that, when passing over to the dryer section, the dry content would be as high as possible (in practice about 40-55%).
  • dry content 15-23%)
  • the web is delivered into a nip contact, wherein the web is pressed against an absorbent felt for displacing the water from web to felt in response to pressure forces.
  • Commonly employed are press designs based on a conventional roll nip or a so-called shoe nip.
  • the press nip can be either single-felted with the web having a felt on just one side or double- felted with water draining into felts on both sides.
  • the press section P includes two successive wet press nips 1, 2 followed by a smoothing press 3.
  • a drawback in the use of smoother felts is poorer dewatering in the actual pressing process, the machine's production suffering.
  • a drawback with the smoothing press is poor runnability as well as higher investment. It is an objective of the present invention to provide an enhanced press section solution, which is capable of avoiding prior art drawbacks, further improving smoothness, reducing a length of the press section, and improving runnability.
  • a press section of the invention is characterized in that the smoothing press is positioned at a location in which the dry content is less than 75%, the smoothing press is provided with a metal belt circle comprising a metal belt adapted to extend around at least one guide element, on the outside of said belt being mounted at least one counter-element providing a contact surface with the belt so as to establish between the belt and the counter-element a web treatment zone, the web to be treated being carried therethrough.
  • the advantage is an improved smoothness of the web and thereby an enhanced heat transfer along the dryer section.
  • the smoothing press provided with a metal belt circle is preferably outfitted with heating elements for heating the metal belt and/or the counter-element in view of warming up the treated web upstream of the dryer section, thus enabling the use of higher steam pressure along the dryer section right from the start.
  • a smoothing press of the invention for the press section of a paper or board machine is characterized in that the smoothing press is provided with a metal belt circle comprising a metal belt adapted to extend around at least one guide element, on the outside of said belt being mounted at least one counter- element providing a contact surface with the belt so as to establish between the belt and the counter-element a web treatment zone, the web to be treated being carried therethrough.
  • Rg. 1 shows schematically one board machine press section of the prior art
  • fig. 2 shows in a schematic view of principle one press section of the invention
  • figs. 3-6 show in schematic views of principle preferred further embodiments for a solution of the invention.
  • Fig. 2 is a schematic view, showing one embodiment for a press section of the invention, wherein a second wet press 2 and a smoothing press 3 of the press section are replaced with a smoothing press 4 based on a metal belt circle and comprising a metal belt 5 adapted to extend around at least one guide element 6, and a counter-element 7 mounted on the outside of the belt circle and comprising preferably a roll, the counter-element providing a contact surface with the belt so as to establish between the belt and the counter-element a web treatment zone PN, the web to be treated being carried therethrough.
  • a wet press nip 1 preceding the smoothing press 4 is preferably implemented as a shoe press.
  • the counter-element 7 can also be disposed inside a fabric loop (not shown), the web being transferred within the treatment zone into the smoothing press nip while supported by the fabric.
  • the fabric not only facilitates feeding the web into the nip but can also take up water draining from the web, thereby further improving the dry content of the web.
  • the web is over one side thereof in contact with the metal belt 5 and over the other side thereof either directly with the surface of the counter-element 7 or with a fabric present on the surface of the counter-element 7.
  • the latter case is pertinent especially with heavy-duty grades, wherein the dewatering in a single nip is not sufficient.
  • Changing the treatment zone length and/or the belt tension is preferably performed by designing at least one guide element 6 to be displaceable and/or adjustable in terms of its size or position, e.g. its angular position.
  • the number of wet press nips upstream of the smoothing press can be more than one. In terms of structural and cost aspects, the most favorable is nevertheless a solution in which the number of traditional press nips is just one.
  • Reference numeral 8 is used to represent metal belt heating elements, which may comprise e.g. an induction heater, an infrared radiator or a gas burner. The heating may also be based on resistive heating.
  • the counter-element 7 can also be provided with separate external heating elements or the counter-element may comprise a thermo roll. Heating the web prior to its passage to the dryer section enables higher steam pressure to be applied from the very start. In addition, a long treatment zone in the smoothing press enables improving the web smoothness, which enhances heat transfer along the dryer section.
  • the extra press element is preferably a roll which, like a roll functioning as the counter-element 7, may or may not be a deflection-compensated roll and which is selected from a group, including: a flexible surface roll, such as a polymer-coated roll, a rubber-coated roll or an elastomer surface roll, a shoe roll, a thermo roll, a metal roll, a fibrous roll, and a composite roll.
  • the counter-element may comprise some other variable profile or permanent profile press element, which may further consist of a number of cross-machine directed successive components.
  • a counter-element implemented in the form of a roll may also consist of a number of cross-machine directed successive components.
  • the press element may have its surface designed to be continuous or discontinuous.
  • the press element can be adapted to be displaceable for changing the treatment zone length and/or the belt tension.
  • An open draw to a smoothing press and thence further, as depicted in fig. 2, is a good solution at lower web speeds of e.g. less than 1000 m/min and preferably less than 800 m/min. Higher speeds can be employed when the web has a higher dry content or more strength.
  • the activation of a belt smoothing press can be performed by means of tail threading blows and conveyors or preferably by drawing the tail with ropes from the side of a smoothing press, followed by spreading the tail across the machine fill.
  • tail threading is a closed belt smoothing press nip that cannot be opened the way of an ordinary press/smoothing nip for the duration of a tail threading process.
  • the belt 5 be in a high position and that the gaps, established thereby jointly with the counter-element 7, open downwards, whereby the gaps are cleaned gravitationally and a closing gap, in particular, does not gather the web into a heap that could ruin the belt.
  • the high position also makes it easier to replace a belt as well as to provide with an overhead extractor hood and thereby to control heat balance and dehumidification.
  • a closed draw especially in high-speed web forming machines of more than 800 m/min, preferably more than 1000 m/min, the lower limit being determined by a grade to be run.
  • a closed draw the web is brought as early as in the very tail threading process in full width to a belt smoothing press and through its treatment zone and further to a drying process while being supported.
  • the draws are challenging as the upstream press nips are in relieved condition and the web is thereby inconsistent with running parameters.
  • Rg. 3 depicts an application, wherein a counter-element 7 is contacted not with an extra press element but with a guide element 6.
  • the nip zone established with a guide element is beneficial as it develops a long preheating range upstream of a higher pressure nip zone PN between the rolls 6, 7.
  • the application provides an easier tail threading process from the roll 7 further to drying, specifically the transition point being disposable at a higher level than in solutions with a longer treatment zone.
  • Fig. 4 depicts a belt smoothing press 4, including just two guide rolls 6 for a belt circle 5.
  • One of the rolls may function as a tension regulator.
  • a higher web temperature produced by the belt smoothing press is utilized in an immediately downstream blast-on drying process 20, which further enhances an increase of the dry content and functions as a transition in the closed draw to a single-wire draw cylinder dryer section.
  • the full-width web is brought to the belt smoothing press 4 by a transfer nip TN, in which the web engages with the surface of the more adhesive metal belt 5 from a final fabric 30 of the press section P.
  • the draw to a drying process D can be effected by using a suction-roll transfer 12 from a roll immediately downstream of the treatment zone.
  • the transfer nips shown in figs. 3-6 have a moving effect on at least one side of the web.
  • the treatment by a belt smoothing press can also be enhanced by means of steam boxes 9 located upstream of the treatment zone for moisturizing the web as well as for raising the web temperature, which also reduces the adherence of web fibers/stickies to the treatment surfaces.
  • a preferred solution is to apply drying to the web upstream of the smoothing press for discouraging adherence to its hot surfaces.
  • Fig. 5 depicts an embodiment, in which a single-nip press Nl is followed by a pre- drying section PD, including e.g. 5-18, preferably 8-15 drying cylinders upstream of a belt smoothing press 4. Consequently, the web has an increased dry content prior to feeding into the belt smoothing press.
  • a special engagement transfer nip 13 which is furnished with a fabric loop and which contributes to a web-and-belt contact and thereby improves heat transfer to the web.
  • the open draw to the dryer section is indicated to include a belt conveyor 14 for a tail threading path.
  • a particularly apt solution is the use of blast-on as shown in fig.
  • the belt smoothing press 4 present downstream of such a top blasting arrangement 20a-20c drying both sides of the web constitutes a preferred application of the invention.
  • the discussed belt smoothing press can be operated at higher temperatures and there is nevertheless a lesser demand of cleaning the treatment surfaces by virtue of the incoming web having drier surfaces.
  • the arrangement is beneficial in connection with a single-nip press, the dry content of a web produced thereby not being as high as that of multi-nip applications.
  • a higher dry content of the web also enables in the arrangement the use of open draws in connection with a belt smoothing press.
  • the web draw from blast-on drying to the belt smoothing press is preferably implemented by means of a transfer fabric 21, wherein a suction roll 22 picks up the web from a drying wire 23 and a transfer nip 24 sets the web in engagement with the metal belt 5.
  • the web upon entering the treatment zone has a dry content preferably within the range of 55-75%, even more preferably within the range of 60-70%, whereby especially the web surfaces are drier and thus particularly suitable for a long treatment-zone belt smoothing press at high temperatures.
  • the treatment surfaces provided in a treatment zone PN have a temperature which is most conveniently less than 150 0 C, preferably 1-3 times the temperature of an incoming web, the highest multipliers being found in solutions in which the belt smoothing press is located immediately downstream of the actual press.
  • a temperature difference between the treatment surfaces can be used to manage the advancement of a web after the treatment zone, e.g. by setting up a temperature difference of more than 15 0 C between the treatment surfaces, the web following the warmer surface downstream of the treatment zone.
  • a temperature difference cannot be set up in favor of the desired surface, it is also possible to use a release chemical on the discussed surface.
  • Fibers and stickies from the web may adhere to the treatment surfaces of a belt smoothing press, which should therefore be provided with doctors and, in addition to or instead of the latter, it is even more advisable to effect cleaning of the surfaces by means of traversing high-pressure washers to eliminate possible dusting.
  • the belt smoothing press according to the invention has been surprisingly found applicable to a web having a distribution of mass density of 4-7%.
  • This range which represents the consistency of web formation (good formation, normalized formation less than about 0,9), has been surprisingly found beneficial for a belt smoothing press as the visual impression of a web with a poorer formation may even deteriorate with a belt smoothing press of the invention.

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  • Paper (AREA)
  • Diaphragms For Electromechanical Transducers (AREA)

Abstract

L'invention concerne une section de presse (P) dans une machine à papier ou carton, comprenant en combinaison au moins une ligne de contact par pression d'égouttage (1) et une presse lisseuse (4) positionnée en aval en termes du sens de marche de la bobine. La presse lisseuse est munie d'un cercle à courroie métallique comprenant une courroie métallique (5) adaptée pour s'étirer autour d'au moins un élément de guidage (6), à l'extérieur de ladite courroie montée au moins un contre-élément (7) fournissant une surface de contact avec la courroie de manière à établir entre la courroie et le contre-élément une zone de traitement de bobine (PN), la bobine à traiter y étant transportée.,
PCT/FI2007/000165 2006-06-28 2007-06-13 Section de presse d'une machine à papier ou carton WO2008000885A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FI20065447 2006-06-28
FI20065447A FI20065447L (fi) 2006-06-28 2006-06-28 Paperi- tai kartonkikoneen puristinosa

Publications (1)

Publication Number Publication Date
WO2008000885A1 true WO2008000885A1 (fr) 2008-01-03

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/FI2007/000165 WO2008000885A1 (fr) 2006-06-28 2007-06-13 Section de presse d'une machine à papier ou carton

Country Status (2)

Country Link
FI (1) FI20065447L (fr)
WO (1) WO2008000885A1 (fr)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2063021A1 (fr) * 2007-12-21 2009-05-27 Metso Paper, Inc. Ensemble courroie et machine pour la fabrication de papier ou de carton comprenant l'ensemble courroie
EP2072672A1 (fr) * 2007-12-20 2009-06-24 Metso Paper, Inc. Agencement en connexion avec la section de pressage d'une machine de fabrication d'une bande de matériau
EP2072671A1 (fr) 2007-12-20 2009-06-24 Stora Enso Oyj Agencement en connexion avec la section de pressage d'une machine de fabrication d'une bande de matériau, et carton ou papier produit dans un tel agencement
EP1985751A3 (fr) * 2007-04-28 2009-12-16 Voith Patent GmbH Partie sèche d'une machine à papier
WO2011151201A1 (fr) * 2010-06-01 2011-12-08 Voith Patent Gmbh Partie humide d'une machine destinée à fabriquer des bandes de matière fibreuse et utilisation d'une telle partie humide
EP2722434A1 (fr) * 2012-10-18 2014-04-23 Metso Paper Inc. Ensemble de courroie destiné à déplacer une bande à partir d'une section de presse d'une machine de fabrication de papier ou carton vers une section de séchage de la machine

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10116840A1 (de) * 2001-04-04 2002-10-17 Voith Paper Patent Gmbh Verfahren und Vorrichtung zum Glätten einer Materialbahn
WO2003064762A1 (fr) * 2002-01-29 2003-08-07 Metso Paper, Inc. Dispositif de traitement et procede d'exploitation du dispositif pour traiter une bande fibreuse couchee ou non couchee
WO2006024695A1 (fr) * 2004-09-02 2006-03-09 Metso Paper, Inc. Appareil de transformation de nappe fibreuse comprenant une courroie metallique en boucle

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10116840A1 (de) * 2001-04-04 2002-10-17 Voith Paper Patent Gmbh Verfahren und Vorrichtung zum Glätten einer Materialbahn
WO2003064762A1 (fr) * 2002-01-29 2003-08-07 Metso Paper, Inc. Dispositif de traitement et procede d'exploitation du dispositif pour traiter une bande fibreuse couchee ou non couchee
WO2006024695A1 (fr) * 2004-09-02 2006-03-09 Metso Paper, Inc. Appareil de transformation de nappe fibreuse comprenant une courroie metallique en boucle

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1985751A3 (fr) * 2007-04-28 2009-12-16 Voith Patent GmbH Partie sèche d'une machine à papier
EP2072672A1 (fr) * 2007-12-20 2009-06-24 Metso Paper, Inc. Agencement en connexion avec la section de pressage d'une machine de fabrication d'une bande de matériau
EP2072671A1 (fr) 2007-12-20 2009-06-24 Stora Enso Oyj Agencement en connexion avec la section de pressage d'une machine de fabrication d'une bande de matériau, et carton ou papier produit dans un tel agencement
WO2009080872A1 (fr) * 2007-12-20 2009-07-02 Stora Enso Oyj Agencement associé à la section de presse d'une machine de formation de feuilles et carton ou papier produit dans un tel agencement
CN101463575B (zh) * 2007-12-20 2012-04-25 美卓造纸机械公司 与幅材成形机的压榨部相关的设备
US8480858B2 (en) 2007-12-20 2013-07-09 Stora Enso Oyj Board or paper produced in an arrangement in connection with the press section of a web-forming machine
EP2063021A1 (fr) * 2007-12-21 2009-05-27 Metso Paper, Inc. Ensemble courroie et machine pour la fabrication de papier ou de carton comprenant l'ensemble courroie
WO2011151201A1 (fr) * 2010-06-01 2011-12-08 Voith Patent Gmbh Partie humide d'une machine destinée à fabriquer des bandes de matière fibreuse et utilisation d'une telle partie humide
EP2722434A1 (fr) * 2012-10-18 2014-04-23 Metso Paper Inc. Ensemble de courroie destiné à déplacer une bande à partir d'une section de presse d'une machine de fabrication de papier ou carton vers une section de séchage de la machine

Also Published As

Publication number Publication date
FI20065447L (fi) 2007-12-29
FI20065447A0 (fi) 2006-06-28

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