WO2006091165A1 - Dispositif d'epaississement - Google Patents

Dispositif d'epaississement Download PDF

Info

Publication number
WO2006091165A1
WO2006091165A1 PCT/SE2006/000256 SE2006000256W WO2006091165A1 WO 2006091165 A1 WO2006091165 A1 WO 2006091165A1 SE 2006000256 W SE2006000256 W SE 2006000256W WO 2006091165 A1 WO2006091165 A1 WO 2006091165A1
Authority
WO
WIPO (PCT)
Prior art keywords
wire
blade
forming roll
dewatering
arrangement according
Prior art date
Application number
PCT/SE2006/000256
Other languages
English (en)
Inventor
Bo Norman
Lennart Hermansson
Original Assignee
Stfi-Packforsk Ab
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 Stfi-Packforsk Ab filed Critical Stfi-Packforsk Ab
Priority to DE602006003070T priority Critical patent/DE602006003070D1/de
Priority to EP06716944A priority patent/EP1853760B1/fr
Publication of WO2006091165A1 publication Critical patent/WO2006091165A1/fr

Links

Classifications

    • 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
    • D21F1/48—Suction apparatus
    • D21F1/483—Drainage foils and bars
    • 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
    • D21F9/003—Complete machines for making continuous webs of paper of the twin-wire type

Definitions

  • the present invention relates to a dewatering apparatus adapted to use in a twin- wire dewatering section of a paper machine. More specifically it relates to such apparatuses comprising a rotating forming roll, a head box for supplying stock, arranged before the forming roll, a closed loop first wire, also called inner wire, adapted to be partly wrapped around the forming roll to a separation line where its contact with the forming roll ceases, and to receive the stock from the head box on its surface not facing the forming roll, a closed loop second wire, also called outer wire, adapted to be partly wrapped around the forming roll on top of the first wire thereby pressing the stock between itself and the first wire.
  • a closed loop first wire also called inner wire
  • a closed loop second wire also called outer wire
  • the amplitude of the under pressure pulses generated by the table rolls increases with the square of the wire speed. At wire speeds in excess of approx. 500m/min. the suction pulses will become so intense that the formation deteriorates.
  • a further principle of twin-wire dewatering uses blades downstream of the forming roll arranged to support the wires and dewater the remaining fibre suspension through the first and second wires. In such apparatuses initial dewatering of the fibre suspension takes place over the forming roll.
  • the wires with the fibre webs and intermediate, remaining un-dewatered fibre suspension are then removed from the forming roll and lead to the subsequent blade arrangement, where dewatering is generated by pressure pulses.
  • dewatering is generated by pressure pulses.
  • local under pressures will be generated at closed areas in the surface of the forming roll. These local under pressures correspond to the suction pulses generated in the table roll dewatering in the fourdrinier dewatering arrangement discussed above.
  • the local under pressures will deflect the first wire and the fibre web positioned thereon towards the roll surface, while the second wire is following an essentially straight path towards the first outer dewatering element following the roll. This results in an expanding space between the wires at the departure from the roll.
  • the dewatering pressure at the roll dewatering is nominally T/R, where T is the tensile stress of the second wire and R is the radius of the roll.
  • T is the tensile stress of the second wire
  • R is the radius of the roll.
  • the shortest technically possible length for the first wire from its departure from the forming roll to its reaching the first support blade has so far been of the magnitude of 200 mm. This may however result in, as is described above, sheet damages.
  • One of the aims with the present invention is therefore to provide an arrangement that substantially reduces these unwanted effects.
  • the dewatering apparatus comprises at least one blade, substantially parallel with the forming roll, arranged to support the roll side of the first wire after the separation line of the forming roll and is arranged such that the tip of the blade is directed against the wire transporting direction, and by that the distance from the separation line to the blade is less than 100 mm.
  • An especially advantageous embodiment of the present invention discloses a distance from the separation line to the blade of less than 30 mm.
  • a further advantageous embodiment of the present invention discloses a blade where the side of the blade facing the forming roll has a shape corresponding to that of the roll surface.
  • a more advantageous embodiment of the present invention discloses a blade where the side of the blade facing the first wire is essentially flat.
  • Fig. 1 discloses a fundamental view of an apparatus according to the present invention.
  • Fig. 2 discloses a detailed side view of a blade according to the present invention.
  • Fig. 3 discloses a side view of a tip of a blade according to the present invention.
  • Fig. 1 discloses a part of a twin-wire forming apparatus with a forming roll 1 , a first wire 2 partly wrapped directly around the forming roll 1 , a second wire 3 wrapped around the forming roll lying on the first wire 2.
  • a head box 4 is arranged with its opening directed substantially in the feeding direction of the wires 2, 3.
  • the head box feeds stock to the nip between the wires 2, 3 wrapped around the forming roll 1. By changing the angle of the opening of the head box 4 against this nip it is possible to change the direction of the stock fed to the forming apparatus.
  • a first support blade 5 is arranged inside of the first wire 2.
  • This blade is designed to support the first wire 2 and to avoid under pressure generation between the first wire 2 and the surface of the forming roll 1 by breaking the fluid capillary between the first wire 2 and the forming roll surface. If this happens early on any substantial force will not form from a local under pressure between roll and wire. This means that any substantial deformation of wire 2 leading to sheet damage will be avoided. This means in turn that the tip of the blade 5 will not be exposed to any significant radial force from the inner wire, thus not causing any significant blade wear by friction.
  • the blade 5 is thus designed so that it supports the inner wire at a distance of at the most approx. 100 mm, and more preferably approx. 20-30 mm downstream of the separation line on the forming roll surface.
  • the blade 5 has for geometrical reasons (the closeness to the roll nip) a very small thickness at its leading edge, of the magnitude of one millimeter, as can be understood from the above equation and from fig. 2.
  • Such a blade gets thereby a low flexural rigidity, and will not be able to carry any significant loads from the inner wire. Therefore the blade 5 is designed so that the inner side has a curvature adjusted to support against the forming roll while the outer side is essentially plane to support the inner wire.
  • Minimum wear between the wire side of the blade 5 and the first wire 2 is obtained by that a suitable water layer is let through between the wire and the blade 5. This is accomplished by a suitable tapering (b, ⁇ ) of the wire side of the tip of blade 5, see figure 3. As can be seen from the figure, this taper angle is ⁇ . Downstream of the first blade 5 other blades can be arranged further supporting and deflecting the wires, thus creating pressure pulses for dewatering of the remaining fibre suspension.
  • the design of the blade according the invention can, of course, be given different forms within the scope of the claims, and is not limited to the example above.
  • the blade may be manufactured from ceramic, polymeric or metallic materials, or combinations thereof. Also other material combinations are possible.

Landscapes

  • Paper (AREA)
  • Sink And Installation For Waste Water (AREA)
  • Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)
  • Centrifugal Separators (AREA)

Abstract

L'invention concerne un dispositif d'épaississement conçu pour être utilisé dans une section d'épaississement à double toile d'une machine à papier, comprenant un rouleau de formation rotatif, une caisse de tête destinée à fournir la pâte, disposée avant le rouleau de formation, une première toile en boucle fermée conçue, d'une part, pour être en partie enroulée autour du rouleau de formation jusqu'à une ligne de séparation où s'arrête le contact avec le rouleau de formation et, d'autre part, pour recevoir la pâte fournie par la caisse de tête sur sa surface opposée au rouleau de formation, une seconde toile en boucle fermée conçue pour être partiellement enroulée autour du rouleau de formation au dessus de la première toile, pour presser la pâte entre les deux toiles, et une première lame, sensiblement parallèle au rouleau de formation, disposée de manière à supporter le côté inférieur de la toile après la ligne de séparation du rouleau de formation, de façon que l'extrémité de la lame soit orientée dans le sens inverse du sens de déplacement de la toile. La distance entre la ligne de séparation et la lame est inférieure à 100 mm. Le fait de supporter la toile à proximité du rouleau de formation permet d'éviter les mouvements au niveau de la première toile et, ainsi, de réduire les effets indésirables, tels que les dommages aux feuilles.
PCT/SE2006/000256 2005-02-28 2006-02-27 Dispositif d'epaississement WO2006091165A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
DE602006003070T DE602006003070D1 (de) 2005-02-28 2006-02-27 Entwässerungsvorrichtung
EP06716944A EP1853760B1 (fr) 2005-02-28 2006-02-27 Dispositif d'egouttage

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE0500447 2005-02-28
SE0500447-8 2005-02-28

Publications (1)

Publication Number Publication Date
WO2006091165A1 true WO2006091165A1 (fr) 2006-08-31

Family

ID=36927704

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/SE2006/000256 WO2006091165A1 (fr) 2005-02-28 2006-02-27 Dispositif d'epaississement

Country Status (4)

Country Link
EP (1) EP1853760B1 (fr)
AT (1) ATE410544T1 (fr)
DE (1) DE602006003070D1 (fr)
WO (1) WO2006091165A1 (fr)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3232825A (en) * 1963-09-16 1966-02-01 Time Inc Dual wire type paper-forming apparatus and methods of forming and dewatering paper
EP0287276A2 (fr) * 1987-04-17 1988-10-19 The Black Clawson Company Machine à double toile horizontale
EP1398412A1 (fr) * 2002-09-13 2004-03-17 Voith Paper Patent GmbH Procédé et section de formage à deux toiles pour la production d'une bande fibreuse

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3232825A (en) * 1963-09-16 1966-02-01 Time Inc Dual wire type paper-forming apparatus and methods of forming and dewatering paper
EP0287276A2 (fr) * 1987-04-17 1988-10-19 The Black Clawson Company Machine à double toile horizontale
EP1398412A1 (fr) * 2002-09-13 2004-03-17 Voith Paper Patent GmbH Procédé et section de formage à deux toiles pour la production d'une bande fibreuse

Also Published As

Publication number Publication date
ATE410544T1 (de) 2008-10-15
EP1853760B1 (fr) 2008-10-08
DE602006003070D1 (de) 2008-11-20
EP1853760A1 (fr) 2007-11-14

Similar Documents

Publication Publication Date Title
US4359827A (en) High speed paper drying
EP1543194B1 (fr) Formation de nappe de papier ou de carton dans un formeur double toile
US3056719A (en) Continuous web forming machine
US4609435A (en) Process and equipment in the forming of paper web
US7608165B2 (en) Multi-layer web formation section
US4300714A (en) Method and apparatus for silencing of webs
KR960007935A (ko) 고속 제지기용 쌍 와이어 포머
EP1853760B1 (fr) Dispositif d'egouttage
US6342125B1 (en) Multi-ply web forming method and apparatus and a multi-ply paper or board product formed hereby
US3432385A (en) Water extraction devices
US3419203A (en) High speed paper making machine
US5427654A (en) Multi-ply web forming apparatus
EP0700472B1 (fr) Procede de production de papier toilette
US6502434B1 (en) Effluent shower for pulp washer
CN207812165U (zh) 网部
EP1853759B1 (fr) Systeme d'egouttage conçu pour etre utilise dans une section d'egouttage a deux toiles d'une machine de traitement de pate
US20070235152A1 (en) On-machine coater
AU575940B2 (en) Web forming device
JP5032845B2 (ja) 紙、板紙又は原料ウェブの巻取り方法、及び、紙、板紙又は原料ウェブのためのワインダ
EP1270806B1 (fr) Caisse de tête avec parois latérales rotatives
CN108699770B (zh) 用于制造纤维料幅的机器的压榨机
WO1997008382A1 (fr) Formeur de bande dans une machine a papier
JP5444362B2 (ja) 複数の排水シューを有するツインファブリック形成部
EP2841643B1 (fr) Section de formation
JP2002115194A (ja) ツインワイヤフォーマ

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application
DPE2 Request for preliminary examination filed before expiration of 19th month from priority date (pct application filed from 20040101)
WWE Wipo information: entry into national phase

Ref document number: 2006716944

Country of ref document: EP

NENP Non-entry into the national phase

Ref country code: DE

WWP Wipo information: published in national office

Ref document number: 2006716944

Country of ref document: EP