EP1342834A2 - Procédé et caisse de tête pour une machine de fabrication d' une bande fibreuse - Google Patents

Procédé et caisse de tête pour une machine de fabrication d' une bande fibreuse Download PDF

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Publication number
EP1342834A2
EP1342834A2 EP03100240A EP03100240A EP1342834A2 EP 1342834 A2 EP1342834 A2 EP 1342834A2 EP 03100240 A EP03100240 A EP 03100240A EP 03100240 A EP03100240 A EP 03100240A EP 1342834 A2 EP1342834 A2 EP 1342834A2
Authority
EP
European Patent Office
Prior art keywords
headbox
lamella
nozzle
structured
range
Prior art date
Legal status (The legal status 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 status listed.)
Withdrawn
Application number
EP03100240A
Other languages
German (de)
English (en)
Other versions
EP1342834A3 (fr
Inventor
Wolfgang Ruf
Hans Loser
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.)
Voith Patent GmbH
Original Assignee
Voith Paper Patent GmbH
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 Voith Paper Patent GmbH filed Critical Voith Paper Patent GmbH
Publication of EP1342834A2 publication Critical patent/EP1342834A2/fr
Publication of EP1342834A3 publication Critical patent/EP1342834A3/fr
Withdrawn legal-status Critical Current

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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
    • D21F1/02—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
    • D21F1/02—Head boxes of Fourdrinier machines

Definitions

  • the invention relates to a method for producing a fibrous web, in particular paper and / or cardboard web, from a stock suspension that is supplied by a headbox whose headbox nozzle is provided with at least one lamella. It also relates to a headbox of a machine for producing a fibrous web, in particular paper and / or cardboard web, with a headbox nozzle which is provided with at least one lamella.
  • the slat end can be sawtooth-like, step-shaped or step-shaped with rounded inner areas.
  • a step lamella is also described, the end region of which tapers step-like from one side. Grooves can be milled into the end area of the lamella. From this publication, a groove lamella is also known in which the grooves run at an angle to the main flow direction. The slat shapes in question are used here to mechanically decouple individual areas of the slat tip from each other and thereby to avoid vibrations of the slat.
  • An object of the invention is to provide an improved method and an improved headbox of the type mentioned at the outset, with which, in particular, shear flows can also be generated in the suspension jet.
  • the lamella surface is advantageously structured accordingly at least in the last third of the headbox nozzle, preferably over its entire length, or advantageously in the region of the nozzle outlet opening and preferably in a diaphragm region of the nozzle outlet opening.
  • the shear flows in question in the suspension jet result in particular in an improvement in the formation, a reduction in the tear length ratio, the possibility of increasing the consistency, an increase in strength in the Z direction and an improvement in the flat position.
  • a more homogeneous leaf structure that is to say a more uniform distribution of the fibers, can positively influence both the formation and the strength values, even at higher substance densities.
  • a more homogeneous sheet structure in which there are no places where there is only fibers or only filler, also results in an improved flat position of the finished web, for example of the finished paper.
  • the lamella surface is structured correspondingly exclusively in the region of the nozzle outlet opening and preferably exclusively in a diaphragm region of the nozzle outlet opening.
  • the structuring is preferably applied at an angle from 0 ° to 90 °, preferably from 20 ° to 70 °, to the machine running direction. However, it can also be attached so that the flow is tangential to the structural elements in the machine running direction and is then deflected at an angle of 0 ° to 90 °. This creates the best conditions for the generation of shear flows in the suspension jet.
  • the structured lamella preferably extends outward through the nozzle gap.
  • a respective structure expediently has a length / width ratio> 2.
  • the slat can be structured continuously up to the slat tip.
  • cross flows can be generated which have no surface effects in comparison to the tooth diaphragm.
  • the lamella can in particular also be structured on two opposite sides, in particular the top and bottom.
  • the structures provided on the two opposite sides are advantageously opposed to one another in order to minimize the resulting total pulse if necessary.
  • a respective structure can be formed or raised by a depression.
  • At least one structure is provided, which is designed as a curved flow guide element, for example.
  • the structures in question can thus be optimized as flow guiding elements.
  • the structures are provided within the headbox nozzle.
  • the structures can be provided in particular in the last third of the headbox nozzle when viewed in the direction of flow.
  • Structures can also advantageously be provided that generate directed flows that remain on one side. This is preferably applicable for multi-layer technology.
  • the wall delimiting the flow space of the headbox nozzle can also be structured.
  • structures are provided on mutually facing sides of adjacent lamellae and / or mutually facing sides of a lamella and the nozzle wall which engage or fit into one another.
  • the lamella length and / or the structure depth, in particular the structure depth in the region of the nozzle gap are selected accordingly to set certain shear flows.
  • the structure depth preferably takes on a value which is preferably in the range from 5% to 95%, preferably in the range from 20% to 80%, of the respective flow channel enclosed by the lamella and / or in the range from 1% to 99% is in the range of 10% to 95%, based on the slat thickness.
  • the structure height preferably assumes a value which is in the range from 1% to 99%, preferably in the range from 20% to 80%, of the respective flow channel enclosed by the lamella.
  • the structuring itself has a pitch in the range from 0.5 mm to 20 mm, preferably in the range from 2 mm to 10 mm, the respective pitch being constant and / or different in the machine direction and / or in the machine direction.
  • At least one, preferably a middle layer, can be loaded with long fiber material to increase the strength.
  • a headbox of a machine for producing a fibrous web, in particular paper and / or cardboard web with a headbox nozzle which is provided with at least one lamella, this headbox being characterized in that at least one Lamella with an at least partially structured surface is provided, wherein the structuring is preferably selected so that transverse flows are generated in the interior of the suspension jet, which lead to shear flows in the suspension jet.
  • FIG. 1 shows a schematic plan view of part of a lamella 10 assigned to a headbox nozzle.
  • an orifice 12 can be seen, which is in the area the outlet opening of the headbox nozzle is arranged and via which the outlet gap of the headbox nozzle can be varied accordingly.
  • the lamella surface is structured in the area of the diaphragm 12.
  • a respective structure that is to say a respective structural element 14 of the structure 16 provided, can have, for example, a length / width ratio H / W> 2.
  • the length L of a respective structural element 14 in the flow direction S (arrow) of the fiber suspension and the width B in the transverse direction are measured.
  • the individual structural elements 14, which are parallel to one another, are inclined with respect to the flow direction S (arrow).
  • they can be designed as elongated incisions, the width B of which is greatest in the middle and decreases towards the two ends (see the illustration in solid lines).
  • structural elements 14 of the type shown in dashed lines in FIG. 1 can also be provided. At least individual structural elements 14 can in particular also be raised.
  • a corresponding structuring can be provided on the upper side and / or the lower side of the lamella 10 in question.
  • the structuring 16 is applied at an angle ⁇ of 0 ° to 90 °, preferably 20 ° to 70 °, to the machine running direction (flow direction S (arrow)).
  • the structuring 16 can also be applied in a curved manner such that the flow contacts the structural elements 14 tangentially in the machine running direction (flow direction S (arrow)) and is subsequently deflected at an angle of 0 ° to 90 °.
  • the structuring has a pitch T in the range from 0.5 mm to 20 mm, preferably in the range from 2 mm to 10 mm.
  • the respective division T in The machine running direction and / or the cross machine direction can be constant and / or different, any configuration of the division being possible.
  • the relevant surfaces of the lamellae 10 to be seen in FIGS. 2 to 5 can also have such a structuring, for example.
  • FIG. 2 shows a schematic longitudinal sectional view of part of an embodiment of a headbox nozzle 18, the flow space 20 of which is delimited by an upper wall 22 and a lower wall 24.
  • an aperture 12 is provided, through which the outlet gap of the headbox nozzle 18 can be varied.
  • the lower wall 24 extends in the flow direction S (arrow) beyond the gap-side end of the upper wall 22 or beyond the orifice 12 provided there.
  • the headbox nozzle 18 is provided with a lamella 10 structured in the area of the diaphragm 12, which in the present case is structured both on its upper side and on its lower side.
  • such structural elements 14 can again be provided as are shown in FIG. 1.
  • the structuring is again provided in the area of the diaphragm 12, and only in this diaphragm area.
  • the lamella 10 extends outward from the flow space 20 in the flow direction S (arrow) beyond the outlet gap. It extends in particular beyond the relevant end of the lower wall 24. In the present case, the lamella 10 is not structured in the region of the tip 26.
  • the structural elements 14 can again each be formed by a depression (compare the illustration in solid lines) or raised (compare the illustration in dashed lines).
  • the structuring has a structure depth t which assumes a value which is in the range from 5% to 95%, preferably in the range from 20% to 80%, of the respective flow channel enclosed by the lamella 10 or assumes a value which is in the range from 1% to 99%, preferably in the range from 10% to 95%, based on the lamella thickness D.
  • FIG. 3 shows a representation of a headbox nozzle 18 that is comparable to FIG. 2, but in the present case the lamella 10 is also structured in the area of the tip 26. In this tip area too, the lamella is structured both on its upper side and on its lower side.
  • the structural elements 14 ' which extend into the area of the tip 26 directly adjoin the structural elements 14 provided in the area of the diaphragm 12.
  • the lamella surface can also be structured accordingly at least in the last third of the headbox nozzle 18, preferably over its entire length.
  • the headbox can at least essentially have the same structure as that according to FIG. 2. Corresponding parts are assigned the same reference numerals.
  • FIG. 4 shows an embodiment of a headbox that is comparable to FIG. 2, but in the present case two slats 10 arranged one above the other are provided. Like the lamella shown in FIG. 2, the two lamellae 10 are again structured on both sides. In the present case, the structuring 16 is also provided in the area of the diaphragm 12.
  • the two lamellae 10 are thus at least essentially designed as the lamella described with reference to FIG. 2.
  • the individual structural elements 14 can also be designed and aligned here again, for example, as is shown in FIG. 1 and has been described with reference to this FIG.
  • this embodiment can, for example, at least essentially have the same structure as that of FIG. 2, the same reference numerals being assigned to corresponding parts.
  • FIG. 5 shows an illustration of a headbox comparable to FIG. 4.
  • the two slats 10 are each only structured on their side facing the other slat.
  • the respective structures 14 can also be provided in particular in the area of the diaphragm 12. Otherwise, this embodiment can at least essentially have the same structure as that of FIG. 4. Corresponding parts are again assigned the same reference numerals.
  • the structures 14 can also be formed here in each case by a depression (compare the illustration in solid lines) or raised (compare the dashed illustration). As can be seen from the right-hand part of FIG. 5, the structures 14 can in particular also be designed such that they engage or fit into one another.
  • the structuring is chosen in particular in such a way that transverse flows are generated in the interior of the suspension jet, which lead to shear flows in the suspension jet.
  • a structure is preferably introduced on a respective lamella in the diaphragm area of the nozzle outlet opening, as a result of which the transverse flows are generated in the interior of the jet.
  • the structuring has a structure height h which assumes a value which is in the range from 1% to 99%, preferably in the range from 20% to 80%, of the respective flow channel enclosed by the lamella 10.
  • FIG. 6 shows a schematic longitudinal sectional view of part of a further embodiment of a headbox nozzle 18, the flow space 20 of which is delimited by an upper wall 22 and a lower wall 24. At the gap-side end of the upper wall 22, an aperture 12 is again provided.
  • the headbox nozzle 18 is provided with a lamella 10 which is structured within the flow space 20 and is structured both on its upper side and on its lower side.
  • the relevant structural elements 14 are raised in the present case.
  • structural elements 14 are also provided on the mutually opposite walls 22, 24 delimiting the flow space 20 of the headbox nozzle 18.
  • the structural elements 14 provided on the lamella 10 or on the walls 22, 24 can also be designed in the present case, for example, such that they engage or fit into one another.
  • the structures or their structural elements preferably have a length / width ratio H / W> 2.
  • the structures can also be continuous up to the lamella tip (see FIG. 3).
  • the cross currents do not produce any surface effects compared to a so-called toothed aperture.
  • both the top and the underside are structured, the structures in question can be opposed to one another in order to minimize the resulting total impulse if necessary.
  • the effect can be influenced by appropriate devices during operation.
  • a more homogeneous leaf structure i.e. a more uniform distribution of the fibers, can positively influence both the formation and the strength values, even with higher material densities.
  • the finished paper will also have a better flat position.
  • At least one layer preferably a middle layer, can be loaded with long fiber material to increase strength. Due to the additionally applied shear forces, back flocculation is hindered and a more homogeneous leaf structure is guaranteed.

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  • Nonwoven Fabrics (AREA)
  • Paper (AREA)
EP03100240A 2002-02-28 2003-02-05 Procédé et caisse de tête pour une machine de fabrication d' une bande fibreuse Withdrawn EP1342834A3 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE10208640A DE10208640A1 (de) 2002-02-28 2002-02-28 Verfahren zur Herstellung einer Faserstoffbahn und Stoffauflauf
DE10208640 2002-02-28

Publications (2)

Publication Number Publication Date
EP1342834A2 true EP1342834A2 (fr) 2003-09-10
EP1342834A3 EP1342834A3 (fr) 2005-06-01

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EP03100240A Withdrawn EP1342834A3 (fr) 2002-02-28 2003-02-05 Procédé et caisse de tête pour une machine de fabrication d' une bande fibreuse

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US (1) US20030159790A1 (fr)
EP (1) EP1342834A3 (fr)
DE (1) DE10208640A1 (fr)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102010001615A1 (de) * 2010-02-05 2011-08-11 Voith Patent GmbH, 89522 Stoffauflauf und Blattbildungseinheit mit einem Stoffauflauf
US20120312487A1 (en) * 2011-05-11 2012-12-13 Hollingsworth & Vose Company Systems and methods for making fiber webs
EP2736713B1 (fr) 2011-07-27 2019-06-26 Hollingsworth & Vose Company Procédé et système pour réaliser des bandes fibreuses
US8753483B2 (en) 2011-07-27 2014-06-17 Hollingsworth & Vose Company Systems and methods for making fiber webs

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE527129C (de) * 1931-06-13 J M Voith Maschinenfabrik Stoffauflauf fuer Papier-, Karton- und Pappenmaschinen
CA936722A (en) * 1970-08-31 1973-11-13 A. Betley Raymond Headbox slice chamber
US3843470A (en) * 1970-08-31 1974-10-22 Beloit Corp Flexible trailing elements in a paper-making machine headbox having projections thereon extending into the slurry flow
JPH06102879B2 (ja) * 1985-07-30 1994-12-14 石川島播磨重工業株式会社 抄紙機のヘツドボツクス
DE4321697C2 (de) * 1993-06-30 2002-05-23 Voith Paper Patent Gmbh Turbulenzeinsatz einer Papiermaschine
DE4329810C2 (de) * 1993-09-03 1997-02-06 Voith Gmbh J M Geometrie des Lamellenendes eines Stoffauflaufes
US6425984B2 (en) * 1995-10-20 2002-07-30 Institute Of Paper Science And Technology, Inc. Layered fiber structure in paper products
DE19652983A1 (de) * 1996-12-19 1997-05-28 Voith Sulzer Papiermasch Gmbh Trennelement eines Mehrschichtenstoffauflaufes
DE10133552A1 (de) * 2001-07-11 2003-01-23 Voith Paper Patent Gmbh Lamelle eines Stoffauflaufs einer Papier- oder Kartonmaschine
DE10245156A1 (de) * 2002-09-27 2004-04-08 Voith Paper Patent Gmbh Stoffauflauf

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Publication number Publication date
US20030159790A1 (en) 2003-08-28
EP1342834A3 (fr) 2005-06-01
DE10208640A1 (de) 2003-09-11

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