EP1693507B1 - Trailing member for a headbox - Google Patents

Trailing member for a headbox Download PDF

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Publication number
EP1693507B1
EP1693507B1 EP06100633A EP06100633A EP1693507B1 EP 1693507 B1 EP1693507 B1 EP 1693507B1 EP 06100633 A EP06100633 A EP 06100633A EP 06100633 A EP06100633 A EP 06100633A EP 1693507 B1 EP1693507 B1 EP 1693507B1
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EP
European Patent Office
Prior art keywords
insert
turbulence
cross
turbulence generator
length
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EP06100633A
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German (de)
French (fr)
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EP1693507A2 (en
EP1693507A3 (en
Inventor
Konstantin Fenkl
Klaus Lehleiter
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Voith Patent GmbH
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Voith Patent GmbH
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Publication of EP1693507A3 publication Critical patent/EP1693507A3/en
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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
    • D21F1/026—Details of the turbulence section

Definitions

  • the invention relates to a turbulence generator for a headbox of a machine for producing a fibrous web, in particular a paper, board or tissue web, from at least one pulp suspension, with a plurality of turbulence tubes for guiding and distributing the at least one pulp suspension, wherein at least one turbulence tube in the flow path the at least one pulp suspension changes at least once from a first cross section to a second cross section and at least one step change in cross section is created by an insert disposed in the turbulence tube having an insert length and an insert outside diameter, the insert having a slenderness ratio in the range of 1: 8 to 1:50, preferably 1:10 to 1:30, and wherein the degree of slimming is the ratio of insert outside diameter to insert length.
  • Such a turbulence generator is for example from German Offenlegungsschrift DE 101 02 087 A1 known.
  • the insert inserted into the turbulence tube is slidable and means are provided by which a change in the ratio L / D of the distance of a cross-sectional change to the end of the turbulence tube to the narrowest hydraulic diameter of this cross-sectional change can be effected.
  • the means for moving the insert may comprise, for example, at least one gear and a gear mesh.
  • an insert is used to influence the flow guidance, especially for equalizing the total volume flow, for setting the desired degree of turbulence and for targeted pressure loss generation.
  • German patent application DE 35 25 760 A1 in this case forms a channel and is in holes of two support plates, which are arranged in the flow direction of the pulp suspension at a certain distance from each other and form a guide member stored.
  • the insert may be surrounded by a spacer tube enclosing it.
  • it is due to its manufacturing process, such as a conventional mechanical processing or injection molding, relatively short, it has only a maximum length of 200 mm. He is thus adaptable only within narrow limits to variety-specific requirements.
  • the invention has the object of providing a turbulence generator with inserts of the type mentioned in such a way that it has a significantly improved range of use for a variety of variety-specific requirements.
  • the object is achieved by the characterizing feature of claim 1.
  • the slimming range of the "long" insert allows the use of the turbulence generator for a variety of purposes variety specific requirements.
  • pulp suspensions with strong segregation tendencies, high air contents and / or chemical affinities for adhesion to the surfaces in contact with the flow, in particular in the area of the headbox nozzle can be positively influenced by the variable design of the "long” inserts.
  • long-fiber pulp suspension such as kraft liners or sack force papers, but also wood-free papers with long-fiber pulp, which can increasingly tend to segregation due to lack of turbulence and thereby cause undesirable effects, in particular streaks in the fibrous web produced, can by variable Execution of the "long" missions are positively influenced.
  • the insert preferably has at least one cross-sectional change designed as a graduated step, which is arranged in the flow path of the at least one fibrous suspension at least in the last third, preferably in the last quarter, in particular in the last fifth of the insert length.
  • This arrangement region plays a decisive role in the degree of turbulence which the flowing pulp suspension has at the end of the turbulence tube and which is thus responsible for the flow properties of the pulp suspension at the beginning of the headbox nozzle.
  • the insert has a plurality of cross-sectional changes formed as a respective increment.
  • This embodiment allows for the continuous generation and maintenance of a minimum degree of turbulence in the pulp suspension. This minimum degree of turbulence is necessary in order not to get a segregation of the pulp suspension.
  • the insert further preferably has a total increment in relation to the insert length in the range from 1:10 to 1: 100, preferably from 1:12 to 1:75, in particular 1:15 to 1:50, wherein the total increment is the difference of the largest Internal insert diameter to insert outside diameter is.
  • This overall increment, in particular the last increment, also plays a decisive role for the degree of turbulence already explained.
  • the insert favorably has a plurality of inner surfaces having a roughness in the range of about 0.4 to about 1.0 microns. This area is particularly favorable for the cleanliness of the inner surfaces and the flow stability of the pulp suspension.
  • the insert In order to prevent complete insertion of the insert into the turbulence tube, it has, in an ideal embodiment, at its inlet end a plate-shaped projection whose outer diameter is greater than the inner diameter of the turbulence tube. Moreover, it is preferably provided at its inlet end with a chamfer, which has a very positive effect on the reduction of the pressure loss at the inlet end.
  • the insert has in a further embodiment along its insert length on the outside at least one web foot, preferably a plurality of more evenly distributed web feet.
  • the insert may consist of a plastic, preferably of a high-conductivity polymer such as in particular PPSU, PPS, PEI, PTFE or the like, or of a corrosion-resistant metal, preferably of stainless steel. Both types of material are particularly suitable for use, with an insert made of a plastic still manufacturing advantages and cost advantages.
  • FIG. 1 shows a schematic longitudinal representation of a turbulence generator 1 of a headbox of a machine for producing a fibrous web according to the prior art.
  • the fibrous web produced from at least one pulp suspension 2 may in particular be a paper, board or tissue web.
  • the turbulence generator 1 comprises a plurality of turbulence tubes 3 for guiding and distributing the at least one fibrous suspension 2.
  • the turbulence tubes 3 are usually arranged in rows and columns and they are in holes 4 of two support plates 5.1, 5.2, in the flow direction S (arrow) the pulp suspension 2 are arranged at a certain distance D from each other and form a guide member 6, stored.
  • the illustrated Turbulence generator 1 has two rows Z 1 , Z 2 on turbulence tubes 3, one speaks of a so-called "two-line”.
  • the respective turbulence tube 3 changes in the course of the flow of the at least one fibrous suspension 2 at least once from a first cross section A 1 to a second cross section A 2 and at least one formed as a step change in cross section change ⁇ A is arranged by a, in the turbulence tube 3 [at least inlet side] Insert 8 generates, which has an insert length L 8 and an insert outer diameter D 8 .
  • FIG. 1 In the execution of FIG. 1 is the cross-sectional change .DELTA.A formed at the end of the insert 8 as an end-step increment 7.
  • the insert 8 changes in its course once again its cross section from a cross section A 3 to the cross section A 1 in forming a second increment 9, wherein the cross section A 3 is the inlet cross section of the insert 8.
  • the second cross section A 2 is at the same time the cross section of the cylindrical or approximately cylindrical part of the turbulence tube 3.
  • the turbulence tube 3 can also be designed in two parts, so that the position of the second increment 9 lies at the contour transition of the two nested parts.
  • the pipe wall thickness of the inserted pipe part fixes the size and the position of the second step jump.
  • the insert 8 has in the prior art due to the possible and common manufacturing processes only an insert length L 8 of a maximum of about 200 mm. As a manufacturing process either mechanical machining or injection molding come into question.
  • FIG. 2 shows a further turbulence generator 1 of a headbox of a machine for producing a fibrous web according to the prior art.
  • the illustrated turbulence generator 1 additionally has a contraction bushing 10 in each turbulence tube 3, which was inserted downstream of the insert 8 into the turbulence tube 1 with the aim of further increasing the degree of turbulence of the fibrous suspension 2 toward the end of the turbulence tube 1.
  • the contraction bushing 10 is normally introduced from the outlet side 11 of the turbulence tube 3, so that in a turbulence tube 3 with a tapered rectangular outlet a contribution of the same without a previous removal of the "inlet" insert is no longer possible.
  • FIG. 3 now shows a turbulence generator 1 according to the invention of a headbox of a machine for producing a fibrous web. Since the basic construction of this turbulence generator 1 in turn essentially that of the in the FIG. 1 is shown, reference is made to the description of this turbulence generator.
  • the insert 8 has a degree of slimming T in the range of 1: 8 to 1:50, preferably 1:10 to 1:30, wherein the slenderness degree T is the ratio of insert outer diameter D 8 to insert length L 8 .
  • the insert 8 has an insert length L 8 , which is smaller in the range of 3 to 150 mm, preferably 5 to 100 mm, than the length L z of the preferably cylindrical or approximately cylindrical part of the turbulence tube 3. Its at least one inner surface 12 has a roughness R a in the range of about 0.4 to about 1.0 microns.
  • Both shown inserts 8 have at their inlet-side ends 13 depending on a plate-shaped projection 14 whose outer diameter D 14 is greater than the tube inner diameter d 3 of the turbulence tube 3, so that a complete Slipping of the respective insert 8 in the associated turbulence tube 3 is prevented.
  • Each insert 8 is also provided at its inlet end 13 with a chamfer 15.
  • the inserts 8 can also be designed without chamfers, wherein the sharp edge that arises in each case can lead to the rupture of fiber flakes due to strong contractions.
  • Each insert 8 also consists of a plastic, preferably of a high-conductivity polymer such as in particular PPSU, PPS, PEI, PTFE or the like, or of a corrosion-resistant metal, preferably of stainless steel.
  • a plastic preferably of a high-conductivity polymer such as in particular PPSU, PPS, PEI, PTFE or the like, or of a corrosion-resistant metal, preferably of stainless steel.
  • the upper insert 8.1 has a constant inner diameter d 8
  • the lower insert has a 8.2 formed as a step jump 9 second cross section change ⁇ A (from A 3 to A 1 ), in the flow of the at least one pulp suspension 2 at least in the last third, preferably in the last quarter, especially in the last fifth, the insert length L 8 is arranged.
  • the respective first cross-sectional change ⁇ A in the flow path of the at least one pulp suspension 2 is formed at the end of the associated insert 8.
  • the change in cross section ⁇ A takes place from a first cross-section A 1 to a second cross-section A 2 , wherein a step jump 7 is formed.
  • the respective insert 8 may have further, as a respective increment formed cross-sectional changes .DELTA.A.
  • Each insert 8 has a total increment in relation to the insert length L 8 in the range of 1:10 to 1: 100, preferably 1:12 to 1:75, in particular 1:15 to 1:50, wherein the total increment is the difference of largest inside diameter d 8 to insert outside diameter D 8 .
  • FIGS. 4 to 6 show further embodiments of inventive inserts 8 for a headbox of a machine for producing a fibrous web.
  • the use 8 of FIG. 4 has a second step change ⁇ A (from A 3 to A 1 ) formed as a step jump 9, which is arranged in the flow path of the at least one fibrous suspension 2 in the first third of the insert length L 8 .
  • FIG. 5 shown insert 8 has a constant inner diameter d 8 over the insert length L 8 and thus corresponds to the upper insert 8.1 of FIG. 3 ,
  • the insert 8 of the FIG. 6 in turn designed as a step jump 9 second cross-sectional change ⁇ A (from A 3 to A 1 ), which is arranged in the flow of the at least one pulp suspension 2 at least in the last third, preferably in the last quarter, especially in the last fifth of the insert length L 8 . It thus corresponds to the lower insert 8.2 of FIG. 3 ,
  • the inserts 8 of the invention FIGS. 3 to 6 have along their insert lengths L 8 on the outside at least one web foot 16, preferably a plurality of more evenly distributed web feet 16.
  • the individual cross-sections of the inserts 8 need not necessarily have a respective rotationally symmetrical cross-sectional contour. Rather, the respective inner cross-sectional contours as well as the corresponding outer cross-sectional contours may have polygons, for example triangular or quadrangular contours.
  • the invention provides a turbulence generator with inserts of the type mentioned in such a way that it has a significantly improved range of use for a variety of variety-specific requirements.

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  • Earth Drilling (AREA)
  • Nonwoven Fabrics (AREA)

Abstract

Headbox turbulator for a machine for making a fibrous web from a fiber suspension comprises a set of tubes, at least one of which has an insert providing at least one stepwise change in diameter. The insert has a ratio of outside diameter to length of 1:8-50 : An independent claim is also included for a process for producing an insert as above, in which functional contours of the insert are produced by machining.

Description

Die Erfindung betrifft einen Turbulenzerzeuger für einen Stoffauflauf einer Maschine zur Herstellung einer Faserstoffbahn, insbesondere einer Papier-, Karton- oder Tissuebahn, aus mindestens einer Faserstoffsuspension, mit einer Vielzahl von Turbulenzrohren zur Führung und Verteilung der mindestens einen Faserstoffsuspension, wobei wenigstens ein Turbulenzrohr im Strömungsverlauf der mindestens einen Faserstoffsuspension sich mindestens einmal von einem ersten Querschnitt auf einen zweiten Querschnitt verändert und zumindest eine als Stufensprung ausgebildete Querschnittsveränderung durch einen, in dem Turbulenzrohr angeordneten Einsatz erzeugt wird, der eine Einsatzlänge und einen Einsatzaußendurchmesser aufweist, wobei der Einsatz einen Schlankheitsgrad im Bereich von 1:8 bis 1:50, vorzugsweise von 1:10 bis 1:30, aufweist und wobei der Schlankheitsgrad das Verhältnis von Einsatzaußendurchmesser zu Einsatzlänge ist.The invention relates to a turbulence generator for a headbox of a machine for producing a fibrous web, in particular a paper, board or tissue web, from at least one pulp suspension, with a plurality of turbulence tubes for guiding and distributing the at least one pulp suspension, wherein at least one turbulence tube in the flow path the at least one pulp suspension changes at least once from a first cross section to a second cross section and at least one step change in cross section is created by an insert disposed in the turbulence tube having an insert length and an insert outside diameter, the insert having a slenderness ratio in the range of 1: 8 to 1:50, preferably 1:10 to 1:30, and wherein the degree of slimming is the ratio of insert outside diameter to insert length.

Ein derartiger Turbulenzerzeuger ist beispielsweise aus der deutschen Offenlegungsschrift DE 101 02 087 A1 bekannt.Such a turbulence generator is for example from German Offenlegungsschrift DE 101 02 087 A1 known.

Der in das Turbulenzrohr eingebrachte Einsatz ist verschiebbar ausgeführt und es sind Mittel vorgesehen, durch die eine Veränderung des Verhältnisses L/D des Abstands einer Querschnittsveränderung zum Ende des Turbulenzrohrs zum engsten hydraulischen Durchmesser dieser Querschnittsveränderung bewirkt werden kann. Das Mittel zum Bewegen des Einsatzes kann beispielsweise mindestens ein Zahnrad und einen Zahnradeingriff aufweisen.The insert inserted into the turbulence tube is slidable and means are provided by which a change in the ratio L / D of the distance of a cross-sectional change to the end of the turbulence tube to the narrowest hydraulic diameter of this cross-sectional change can be effected. The means for moving the insert may comprise, for example, at least one gear and a gear mesh.

Allgemein dient ein Einsatz zur Beeinflussung der Strömungsführung, vor allem zur Vergleichmäßigung des Gesamtvolumenstroms, zur Einstellung des gewünschten Turbulenzgrads und zur gezielten Druckverlusterzeugung.In general, an insert is used to influence the flow guidance, especially for equalizing the total volume flow, for setting the desired degree of turbulence and for targeted pressure loss generation.

In der Praxis kommt es nun vor, dass der Bereich zwischen dem Beginn des Turbulenzrohrs und dem verschiebbaren Einsatz bei normaler, das heißt horizontaler oder annähernd horizontaler Einbaulage des Stoffauflaufs einen natürlichen Ablauf der Faserstoffsuspension verhindert und es bei längeren Stillstandszeiten der Maschine zur Herstellung einer Faserstoffbahn zum Antrocknen von Fasern und dadurch zur Änderung der Rohrgeometrie bis hin zu einer Verstopfung des Turbulenzrohrs kommen kann. Überdies ist die konstruktive Ausführung des Mittels zum Bewegen des Einsatzes sehr aufwendig und damit teuer in der Herstellung. Zudem kann ein wirkliches Verschieben des Einsatzes nicht immer gewährleistet werden. Weiterhin ist zwar eine Verschiebung des Einsatzes problemlos gegeben, der Bereich der Verschiebung ist jedoch konstruktiv festgelegt, so dass nicht immer eine optimale Positionierung des Einsatzes möglich ist.In practice, it now happens that the area between the beginning of the turbulence tube and the displaceable insert in normal, that is horizontal or approximately horizontal mounting position of the headbox prevents natural flow of the pulp suspension and for longer downtime of the machine for producing a fibrous web for Drying of fibers and thereby changing the tube geometry up to a blockage of the turbulence tube can come. Moreover, the structural design of the means for moving the insert is very expensive and therefore expensive to manufacture. In addition, a real move the use can not always be guaranteed. Furthermore, although a shift of the insert is given easily, the range of displacement is constructively determined, so that not always optimal positioning of the insert is possible.

Weiterhin ist aus den deutschen Offenlegungsschriften DE 35 25 760 A1 und DE 199 42 047 A1 jeweils ein Einsatz für einen Turbulenzerzeuger für einen Stoffauflauf bekannt.Furthermore, from the German Offenlegungsschriften DE 35 25 760 A1 and DE 199 42 047 A1 in each case an insert for a turbulence generator for a headbox known.

Der Einsatz der deutschen Offenlegungsschrift DE 35 25 760 A1 bildet hierbei einen Kanal und ist in Löchern von zwei Trägerplatten, die in Strömungsrichtung der Faserstoffsuspension in einer bestimmten Distanz voneinander angeordnet sind und ein Führungsteil bilden, gelagert. Der Einsatz kann von einem ihn umschließenden Distanzrohr umgeben sein. Zudem ist er aufgrund seines Herstellungsverfahrens, beispielsweise einer üblichen mechanischen Bearbeitung oder eines Spritzgusses, relativ kurz, er weist lediglich eine Länge von maximal 200 mm auf. Er ist somit lediglich in engen Grenzen an sortenspezifische Anforderungen anpassbar.The use of German patent application DE 35 25 760 A1 in this case forms a channel and is in holes of two support plates, which are arranged in the flow direction of the pulp suspension at a certain distance from each other and form a guide member stored. The insert may be surrounded by a spacer tube enclosing it. In addition, it is due to its manufacturing process, such as a conventional mechanical processing or injection molding, relatively short, it has only a maximum length of 200 mm. He is thus adaptable only within narrow limits to variety-specific requirements.

Eine Abhilfe für die engen Grenzen wurde in der Vergangenheit dadurch geschaffen, dass zusätzlich eine Kontraktionsbuchse stromabwärts des Einsatzes in das Turbulenzrohr mit dem Ziel eingesetzt wurde, den Turbulenzgrad der Faserstoffsuspension gegen Ende des Turbulenzrohrs nochmals zu erhöhen. Dadurch ergab sich gegebenenfalls wiederum das Problem des Antrocknens von Fasern und der damit verbundenen Änderung der Rohrgeometrie bis hin zu einer Verstopfung des Turbulenzrohrs.A remedy for the narrow limits has been provided in the past by additionally using a contraction bushing downstream of the insert into the turbulence tube with the aim of further increasing the degree of turbulence of the pulp suspension towards the end of the turbulence tube. As a result, in turn, the problem of the drying of fibers and the associated change in the tube geometry up to a blockage of the turbulence tube, where appropriate, resulted.

Überdies ist bei einem Turbulenzrohr mit einem sich verjüngenden Rechteckauslauf, wie es beispielsweise aus der europäischen Patentanmeldung EP 1 386 999 A1 bekannt ist, aufgrund der Rohrabflachung ein Einbau einer Kontraktionsbuchse von der bisher üblichen Turbulenzrohr-Auslaufseite her nicht mehr möglich.Moreover, in a turbulence tube with a tapered rectangular outlet, as it is for example from the European Patent Application EP 1 386 999 A1 is known, due to the pipe flattening installation of a contraction bushing from the usual turbulence pipe outlet side no longer possible.

Der Erfindung liegt die Aufgabe zugrunde, einen Turbulenzerzeuger mit Einsätzen der eingangs genannten Art derart weiterzubilden, dass er ein deutlich verbessertes Verwendungsspektrum für verschiedenste sortenspezifische Anforderungen aufweist.The invention has the object of providing a turbulence generator with inserts of the type mentioned in such a way that it has a significantly improved range of use for a variety of variety-specific requirements.

Die Aufgabe wird erfindungsgemäß durch das kennzeichnende Merkmal des Anspruchs 1 gelöst.The object is achieved by the characterizing feature of claim 1.

Die erfindungsgemäße Aufgabe wird auf diese Weise vollkommen gelöst.The object of the invention is completely solved in this way.

Damit wird möglichst nahe an der sich vergrößernden Querschnittsfläche des Turbulenzrohrs ein letzter Stufensprung aufgrund des Endes des Einsatzes geschaffen.Thus, a last increment due to the end of the insert is created as close as possible to the increasing cross-sectional area of the turbulence tube.

Der Bereich für den Schlankheitsgrad des "langen" Einsatzes ermöglicht die Verwendung des Turbulenzerzeugers für verschiedenste sortenspezitische Anforderungen. So konnen insbesondere Faserstoffsuspensionen mit starken Entmischungsneigungen, hohen Luftgehalten und/oder chemischen Affinitäten zur Anhaftung an den strömungsberührten Flächen, insbesondere im Bereich der Stoffauflaufdüse, durch die variable Ausführung der "langen" Einsätze positiv beeinflusst werden. Auch langfaserige Faserstoffsuspension, wie zum Beispiel Kraft-Liner oder Sackkraft-Papiere, aber auch holzfreie Papiere mit langfaserigem Zellstoffanteil, die verstärkt zur Entmischung aufgrund mangelnder Turbulenz neigen können und dadurch unerwünschte Effekte, insbesondere Streifigkeiten, in der hergestellten Faserstoffbahn bewirken, können durch die variable Ausführung der "langen" Einsätze positiv beeinflusst werden. Es verbessert sich schlichtweg das Verwendungsspektrum eines Turbulenzerzeugers bei Verwendung der erfindungsgemäßen "langen" Einsätze. Dies wird insbesondere auch durch die verhältnismäßig einfache Austauschbarkeit der "langen" Inserts ermöglicht, die eine nachträgliche Anpassung, beispielsweise bei einem Sorten- oder Produktwechsel, jederzeit zulässt.The slimming range of the "long" insert allows the use of the turbulence generator for a variety of purposes variety specific requirements. Thus, in particular pulp suspensions with strong segregation tendencies, high air contents and / or chemical affinities for adhesion to the surfaces in contact with the flow, in particular in the area of the headbox nozzle, can be positively influenced by the variable design of the "long" inserts. Also long-fiber pulp suspension, such as kraft liners or sack force papers, but also wood-free papers with long-fiber pulp, which can increasingly tend to segregation due to lack of turbulence and thereby cause undesirable effects, in particular streaks in the fibrous web produced, can by variable Execution of the "long" missions are positively influenced. It simply improves the range of use of a turbulence generator when using the "long" inserts according to the invention. This is made possible in particular by the relatively simple interchangeability of the "long" inserts, which permits subsequent adaptation, for example during a variety or product change, at any time.

Der Einsatz weist bevorzugt zumindest eine als Stufensprung ausgebildete Querschnittsveränderung auf, die im Strömungsverlauf der mindestens einen Faserstoffsuspension mindestens im letzten Drittel, vorzugsweise im letzten Viertel, insbesondere im letzten Fünftel, der Einsatzlänge angeordnet ist. Dieser Anordnungsbereich spielt eine entscheidende Rolle für den Turbulenzgrad, den die strömende Faserstoffsuspension am Ende des Turbulenzrohrs aufweist und der damit für die Strömungseigenschaften der Faserstoffsuspension am Anfang der Stoffauflaufdüse verantwortlich ist.The insert preferably has at least one cross-sectional change designed as a graduated step, which is arranged in the flow path of the at least one fibrous suspension at least in the last third, preferably in the last quarter, in particular in the last fifth of the insert length. This arrangement region plays a decisive role in the degree of turbulence which the flowing pulp suspension has at the end of the turbulence tube and which is thus responsible for the flow properties of the pulp suspension at the beginning of the headbox nozzle.

Weiterhin weist der Einsatz mehrere als ein jeweiliger Stufensprung ausgebildete Querschnittsveränderungen auf. Diese Ausgestaltung ermöglicht die fortwährende Generierung und Aufrechterhaltung eines minimalen Turbulenzgrads in der Faserstoffsuspension. Dieser minimale Turbulenzgrad ist notwendig, um nicht eine Entmischung der Faserstoffsuspension zu erhalten.Furthermore, the insert has a plurality of cross-sectional changes formed as a respective increment. This embodiment allows for the continuous generation and maintenance of a minimum degree of turbulence in the pulp suspension. This minimum degree of turbulence is necessary in order not to get a segregation of the pulp suspension.

Der Einsatz weist ferner bevorzugt einen Gesamtstufensprung im Verhältnis zur Einsatzlänge im Bereich von 1:10 bis 1:100, vorzugsweise von 1:12 bis 1:75, insbesondere 1:15 bis 1:50, auf, wobei der Gesamtstufensprung die Differenz von größtem Einsatzinnendurchmesser zu Einsatzaußendurchmesser ist. Auch dieser Gesamtstufensprung, insbesondere der letzte Stufensprung, spielt wiederum eine entscheidende Rolle für den bereits erläuterten Turbulenzgrad.The insert further preferably has a total increment in relation to the insert length in the range from 1:10 to 1: 100, preferably from 1:12 to 1:75, in particular 1:15 to 1:50, wherein the total increment is the difference of the largest Internal insert diameter to insert outside diameter is. This overall increment, in particular the last increment, also plays a decisive role for the degree of turbulence already explained.

Auch weist der Einsatz in günstiger Weise mehrere Innenflächen auf, die eine Rauhigkeit im Bereich von etwa 0,4 bis etwa 1,0 µm aufweisen. Dieser Bereich ist insbesondere für die Sauberhaltung der Innenflächen und die Strömungsstabilität der Faserstoffsuspension günstig.Also, the insert favorably has a plurality of inner surfaces having a roughness in the range of about 0.4 to about 1.0 microns. This area is particularly favorable for the cleanliness of the inner surfaces and the flow stability of the pulp suspension.

Damit ein vollständiges Hineingleiten des Einsatzes in das Turbulenzrohr verhindert wird, weist er in idealer Ausgestaltung an seinem einlaufseitigen Ende einen tellerförmigen Ansatz auf, dessen Außendurchmesser größer ist als der Innendurchmesser des Turbulenzrohrs. Überdies ist er an seinem einlaufseitigen Ende bevorzugt mit einer Fase versehen, die sich überaus positiv auf die Reduktion des Druckverlusts am einlaufseitigen Ende auswirkt.In order to prevent complete insertion of the insert into the turbulence tube, it has, in an ideal embodiment, at its inlet end a plate-shaped projection whose outer diameter is greater than the inner diameter of the turbulence tube. Moreover, it is preferably provided at its inlet end with a chamfer, which has a very positive effect on the reduction of the pressure loss at the inlet end.

Der Einsatz weist in weiterer Ausgestaltung entlang seiner Einsatzlänge außenseitig zumindest einen Stegfuß, vorzugsweise mehrere insbesondere gleichmäßig verteilte Stegfüße auf. Damit kann einer möglichen Deformation des Einsatzes aufgrund der während des Betriebs der Maschine herrschenden Drücke vorgebeugt werden Weiterhin kann der Einsatz aus einem Kunststoff, vorzugsweise aus einem Hochleitungspolymer wie insbesondere PPSU, PPS, PEI, PTFE oder dergleichen, oder aus einem korrosionsbeständigen Metall, vorzugsweise aus Edelstahl, bestehen. Beide Materialarten eignen sich in besonderer Weise für die Verwendung, wobei ein Einsatz aus einem Kunststoff noch fertigungstechnische Vorteile und Kostenvorteile erbringt.The insert has in a further embodiment along its insert length on the outside at least one web foot, preferably a plurality of more evenly distributed web feet. Thus, a possible deformation of the insert due to the prevailing during operation of the machine pressures can be prevented Furthermore, the insert may consist of a plastic, preferably of a high-conductivity polymer such as in particular PPSU, PPS, PEI, PTFE or the like, or of a corrosion-resistant metal, preferably of stainless steel. Both types of material are particularly suitable for use, with an insert made of a plastic still manufacturing advantages and cost advantages.

Weitere Merkmale und Vorteile der Erfindung ergeben sich aus der nachfolgenden Beschreibung bevorzugter Ausführungsbeispiele unter Bezugnahme auf die Zeichnung.Further features and advantages of the invention will become apparent from the following description of preferred embodiments with reference to the drawings.

Es zeigen in schematischen Längsschnittdarstellungen

Figur 1
einen Turbulenzerzeuger eines Stoffauflaufs einer Maschine zur Herstellung einer Faserstoffbahn gemäß dem Stand der Technik;
Figur 2
einen weiteren Turbulenzerzeuger eines Stoffauflaufs einer Maschine zur Herstellung einer Faserstoffbahn gemäß dem Stand der Technik;
Figur 3
einen erfindungsgemäßen Turbulenzerzeuger eines Stoffauflaufs einer Maschine zur Herstellung einer Faserstoffbahn; und
Figuren 4 bis 6
weitere Ausführungsformen erfindungsgemäßer Einsätze für einen Stoffauflauf einer Maschine zur Herstellung einer Faserstoffbahn.
They show in schematic longitudinal sectional views
FIG. 1
a turbulator of a headbox of a machine for producing a fibrous web according to the prior art;
FIG. 2
another turbulence generator of a headbox of a machine for producing a fibrous web according to the prior art;
FIG. 3
a turbulence generator according to the invention of a headbox of a machine for producing a fibrous web; and
FIGS. 4 to 6
Further embodiments of inventive inserts for a headbox of a machine for producing a fibrous web.

Die Figur 1 zeigt in schematischer Längsdarstellung einen Turbulenzerzeuger 1 eines Stoffauflaufs einer Maschine zur Herstellung einer Faserstoffbahn gemäß dem Stand der Technik. Bei der aus mindestens einer Faserstoffsuspension 2 hergestellten Faserstoffbahn kann es sich insbesondere um eine Papier-, Karton-oder Tissuebahn handeln.The FIG. 1 shows a schematic longitudinal representation of a turbulence generator 1 of a headbox of a machine for producing a fibrous web according to the prior art. The fibrous web produced from at least one pulp suspension 2 may in particular be a paper, board or tissue web.

Der Turbulenzerzeuger 1 umfasst eine Vielzahl von Turbulenzrohren 3 zur Führung und Verteilung der mindestens einen Faserstoffsuspension 2. Die Turbulenzrohre 3 sind üblicherweise in Zeilen und Spalten angeordnet und sie sind dabei in Löchern 4 von zwei Trägerplatten 5.1, 5.2, die in Strömungsrichtung S (Pfeil) der Faserstoffsuspension 2 in einer bestimmten Distanz D voneinander angeordnet sind und ein Führungsteil 6 bilden, gelagert. Der dargestellte Turbulenzerzeuger 1 weist zwei Zeilen Z1, Z2 an Turbulenzrohren 3 auf, man spricht von einem so genannten "Zwei-Zeiler".The turbulence generator 1 comprises a plurality of turbulence tubes 3 for guiding and distributing the at least one fibrous suspension 2. The turbulence tubes 3 are usually arranged in rows and columns and they are in holes 4 of two support plates 5.1, 5.2, in the flow direction S (arrow) the pulp suspension 2 are arranged at a certain distance D from each other and form a guide member 6, stored. The illustrated Turbulence generator 1 has two rows Z 1 , Z 2 on turbulence tubes 3, one speaks of a so-called "two-line".

Das jeweilige Turbulenzrohr 3 verändert im Strömungsverlauf der mindestens einen Faserstoffsuspension 2 sich mindestens einmal von einem ersten Querschnitt A1 auf einen zweiten Querschnitt A2 und zumindest eine als Stufensprung 7 ausgebildete Querschnittsveränderung △A wird durch einen, in dem Turbulenzrohr 3 [zumindest einlaufseitig] angeordneten Einsatz 8 erzeugt, der eine Einsatzlänge L8 und einen Einsatzaußendurchmesser D8 aufweist.The respective turbulence tube 3 changes in the course of the flow of the at least one fibrous suspension 2 at least once from a first cross section A 1 to a second cross section A 2 and at least one formed as a step change in cross section change △ A is arranged by a, in the turbulence tube 3 [at least inlet side] Insert 8 generates, which has an insert length L 8 and an insert outer diameter D 8 .

In der Ausführung der Figur 1 ist die Querschnittsveränderung ΔA am Ende des Einsatzes 8 als endseitiger Stufensprung 7 ausgebildet. Zudem ändert der Einsatz 8 in seinem Lauf noch einmal seinen Querschnitt von einem Querschnitt A3 auf den Querschnitt A1 bei Ausbildung eines zweiten Stufensprungs 9, wobei der Querschnitt A3 der Einlaufquerschnitt der Einsatzes 8 ist. Der zweite Querschnitt A2 ist zugleich der Querschnitt des zylindrischen oder annähernd zylindrischen Teils des Turbulenzrohrs 3.In the execution of FIG. 1 is the cross-sectional change .DELTA.A formed at the end of the insert 8 as an end-step increment 7. In addition, the insert 8 changes in its course once again its cross section from a cross section A 3 to the cross section A 1 in forming a second increment 9, wherein the cross section A 3 is the inlet cross section of the insert 8. The second cross section A 2 is at the same time the cross section of the cylindrical or approximately cylindrical part of the turbulence tube 3.

Weiterhin kann das Turbulenzrohr 3 auch zweiteilig ausgeführt sein, so dass die Position des zweiten Stufensprungs 9 am Konturübergang der beiden ineinander gesteckten Teile liegt. Dabei fixiert die Rohrwandungsdicke des eingesteckten Rohrteils die Größe und die Lage des zweiten Stufensprungs 9.Furthermore, the turbulence tube 3 can also be designed in two parts, so that the position of the second increment 9 lies at the contour transition of the two nested parts. The pipe wall thickness of the inserted pipe part fixes the size and the position of the second step jump. 9

Der Einsatz 8 weist im Stand der Technik aufgrund der möglichen und gängigen Herstellungsverfahren lediglich eine Einsatzlänge L8 von maximal etwa 200 mm auf. Als Herstellungsverfahren kommen entweder eine mechanische Bearbeitung oder ein Spritzguss in Frage.The insert 8 has in the prior art due to the possible and common manufacturing processes only an insert length L 8 of a maximum of about 200 mm. As a manufacturing process either mechanical machining or injection molding come into question.

Die Figur 2 zeigt einen weiteren Turbulenzerzeuger 1 eines Stoffauflaufs einer Maschine zur Herstellung einer Faserstoffbahn gemäß dem Stand der Technik.The FIG. 2 shows a further turbulence generator 1 of a headbox of a machine for producing a fibrous web according to the prior art.

Dieser entspricht im Wesentlichen dem in der Figur 1 dargestellten Turbulenzerzeuger 1, so dass auf dessen Beschreibung verwiesen wird.This corresponds essentially to that in the FIG. 1 illustrated turbulence generator 1, so that reference is made to the description thereof.

Der dargestellte Turbulenzerzeuger 1 weist in jedem Turbulenzrohr 3 zusätzlich noch eine Kontraktionsbuchse 10 auf, die stromabwärts des Einsatzes 8 in das Turbulenzrohr 1 mit dem Ziel eingesetzt wurde, den Turbulenzgrad der Faserstoffsuspension 2 gegen Ende des Turbulenzrohrs 1 nochmals zu erhöhen. Die Kontraktionsbuchse 10 wird normalerweise von der Auslaufseite 11 des Turbulenzrohrs 3 eingebracht, so dass bei einem Turbulenzrohr 3 mit einem sich verjüngenden Rechteckauslauf eine Einbringung derselben ohne ein vorheriges Entfernen des "Einlauf"-Inserts nicht mehr möglich ist.The illustrated turbulence generator 1 additionally has a contraction bushing 10 in each turbulence tube 3, which was inserted downstream of the insert 8 into the turbulence tube 1 with the aim of further increasing the degree of turbulence of the fibrous suspension 2 toward the end of the turbulence tube 1. The contraction bushing 10 is normally introduced from the outlet side 11 of the turbulence tube 3, so that in a turbulence tube 3 with a tapered rectangular outlet a contribution of the same without a previous removal of the "inlet" insert is no longer possible.

Die Figur 3 zeigt nun einen erfindungsgemäßen Turbulenzerzeuger 1 eines Stoffauflaufs einer Maschine zur Herstellung einer Faserstoffbahn. Da die Grundkonstruktion dieses Turbulenzerzeugers 1 im Wesentlichen wiederum der des in der Figur 1 dargestellten Turbulenzerzeugers 1 entspricht, wird auf dessen Beschreibung verwiesen.The FIG. 3 now shows a turbulence generator 1 according to the invention of a headbox of a machine for producing a fibrous web. Since the basic construction of this turbulence generator 1 in turn essentially that of the in the FIG. 1 is shown, reference is made to the description of this turbulence generator.

Der Einsatz 8 weist einen Schlankheitsgrad T im Bereich von 1:8 bis 1:50, vorzugsweise von 1:10 bis 1:30, auf, wobei der Schlankheitsgrad T das Verhältnis von Einsatzaußendurchmesser D8 zu Einsatzlänge L8 ist.The insert 8 has a degree of slimming T in the range of 1: 8 to 1:50, preferably 1:10 to 1:30, wherein the slenderness degree T is the ratio of insert outer diameter D 8 to insert length L 8 .

Weiterhin weist der Einsatz 8 eine Einsatzlänge L8 auf, die im Bereich von 3 bis 150 mm, vorzugsweise von 5 bis 100 mm, kleiner ist als die Länge Lz des vorzugsweise zylindrischen oder annähernd zylindrischen Teils des Turbulenzrohrs 3. Seine mindestens eine Innenfläche 12 weist eine Rauhigkeit Ra im Bereich von etwa 0,4 bis etwa 1,0 µm auf.Furthermore, the insert 8 has an insert length L 8 , which is smaller in the range of 3 to 150 mm, preferably 5 to 100 mm, than the length L z of the preferably cylindrical or approximately cylindrical part of the turbulence tube 3. Its at least one inner surface 12 has a roughness R a in the range of about 0.4 to about 1.0 microns.

Beide dargestellten Einsätze 8 weisen an ihren einlaufseitigen Enden 13 je einen tellerförmigen Ansatz 14 auf, dessen Außendurchmesser D14 größer ist als der Rohrinnendurchmesser d3 des Turbulenzrohrs 3, so dass ein vollständiges Hineingleiten des jeweiligen Einsatzes 8 in das dazugehörige Turbulenzrohr 3 verhindert wird. Jeder Einsatz 8 ist zudem an seinem einlaufseitigen Ende 13 mit einer Fase 15 versehen. Selbstverständlich können die Einsätze 8 auch ohne Fasen ausgeführt sein, wobei die dabei jeweils entstehende Scharfkantigkeit zum Aufreißen von Faserflocken aufgrund starker Kontraktionen führen kann.Both shown inserts 8 have at their inlet-side ends 13 depending on a plate-shaped projection 14 whose outer diameter D 14 is greater than the tube inner diameter d 3 of the turbulence tube 3, so that a complete Slipping of the respective insert 8 in the associated turbulence tube 3 is prevented. Each insert 8 is also provided at its inlet end 13 with a chamfer 15. Of course, the inserts 8 can also be designed without chamfers, wherein the sharp edge that arises in each case can lead to the rupture of fiber flakes due to strong contractions.

Jeder Einsatz 8 besteht zudem aus einem Kunststoff, vorzugsweise aus einem Hochleitungspolymer wie insbesondere PPSU, PPS, PEI, PTFE oder dergleichen, oder aus einem korrosionsbeständigen Metall, vorzugsweise aus Edelstahl.Each insert 8 also consists of a plastic, preferably of a high-conductivity polymer such as in particular PPSU, PPS, PEI, PTFE or the like, or of a corrosion-resistant metal, preferably of stainless steel.

Der obere Einsatz 8.1 weist einen konstanten Innendurchmesser d8 auf, wohingegen der untere Einsatz 8.2 eine als Stufensprung 9 ausgebildete zweite Querschnittsveränderung △A (von A3 auf A1) aufweist, die im Strömungsverlauf der mindestens einen Faserstoffsuspension 2 mindestens im letzten Drittel, vorzugsweise im letzten Viertel, insbesondere im letzten Fünftel, der Einsatzlänge L8 angeordnet ist.The upper insert 8.1 has a constant inner diameter d 8 , whereas the lower insert has a 8.2 formed as a step jump 9 second cross section change △ A (from A 3 to A 1 ), in the flow of the at least one pulp suspension 2 at least in the last third, preferably in the last quarter, especially in the last fifth, the insert length L 8 is arranged.

Die jeweils erste Querschnittsveränderung △A im Strömungsverlauf der mindestens einen Faserstoffsuspension 2 ist am Ende des dazugehörigen Einsatzes 8 ausgebildet. Die Querschnittsveränderung △A erfolgt von einem ersten Querschnitt A1 auf einen zweiten Querschnitt A2, wobei ein Stufensprung 7 ausgebildet wird.The respective first cross-sectional change △ A in the flow path of the at least one pulp suspension 2 is formed at the end of the associated insert 8. The change in cross section △ A takes place from a first cross-section A 1 to a second cross-section A 2 , wherein a step jump 7 is formed.

Selbstverständlich kann der jeweilige Einsatz 8 noch weitere, als ein jeweiliger Stufensprung ausgebildete Querschnittsveränderungen ΔA aufweisen.Of course, the respective insert 8 may have further, as a respective increment formed cross-sectional changes .DELTA.A.

Jeder Einsatz 8 weist einen Gesamtstufensprung im Verhältnis zur Einsatzlänge L8 im Bereich von 1:10 bis 1:100, vorzugsweise von 1:12 bis 1:75, insbesondere 1:15 bis 1:50, auf, wobei der Gesamtstufensprung die Differenz von größtem Einsatzinnendurchmesser d8 zu Einsatzaußendurchmesser D8 ist.Each insert 8 has a total increment in relation to the insert length L 8 in the range of 1:10 to 1: 100, preferably 1:12 to 1:75, in particular 1:15 to 1:50, wherein the total increment is the difference of largest inside diameter d 8 to insert outside diameter D 8 .

Die Figuren 4 bis 6 zeigen weitere Ausführungsformen erfindungsgemäßer Einsätze 8 für einen Stoffauflauf einer Maschine zur Herstellung einer Faserstoffbahn.The FIGS. 4 to 6 show further embodiments of inventive inserts 8 for a headbox of a machine for producing a fibrous web.

Der Einsatz 8 der Figur 4 weist eine als Stufensprung 9 ausgebildete zweite Querschnittsveränderung ΔA (von A3 auf A1) auf, die im Strömungsverlauf der mindestens einen Faserstoffsuspension 2 im ersten Drittel der Einsatzlänge L8 angeordnet ist.The use 8 of FIG. 4 has a second step change ΔA (from A 3 to A 1 ) formed as a step jump 9, which is arranged in the flow path of the at least one fibrous suspension 2 in the first third of the insert length L 8 .

Der in Figur 5 dargestellte Einsatz 8 hingegen weist einen konstanten Innendurchmesser d8 über die Einsatzlänge L8 auf und entspricht somit dem oberen Einsatz 8.1 der Figur 3.The in FIG. 5 shown insert 8, however, has a constant inner diameter d 8 over the insert length L 8 and thus corresponds to the upper insert 8.1 of FIG. 3 ,

Und schließlich weist der Einsatz 8 der Figur 6 wiederum eine als Stufensprung 9 ausgebildete zweite Querschnittsveränderung ΔA (von A3 auf A1) auf, die im Strömungsverlauf der mindestens einen Faserstoffsuspension 2 mindestens im letzten Drittel, vorzugsweise im letzten Viertel, insbesondere im letzten Fünftel, der Einsatzlänge L8 angeordnet ist. Er entspricht somit dem unteren Einsatz 8.2 der Figur 3.And finally, the insert 8 of the FIG. 6 in turn designed as a step jump 9 second cross-sectional change ΔA (from A 3 to A 1 ), which is arranged in the flow of the at least one pulp suspension 2 at least in the last third, preferably in the last quarter, especially in the last fifth of the insert length L 8 . It thus corresponds to the lower insert 8.2 of FIG. 3 ,

Die erfindungsgemäßen Einsätze 8 der Figuren 3 bis 6 weisen entlang ihrer Einsatzlängen L8 außenseitig zumindest je einen Stegfuß 16 , vorzugsweise mehrere insbesondere gleichmäßig verteilte Stegfüße 16 auf.The inserts 8 of the invention FIGS. 3 to 6 have along their insert lengths L 8 on the outside at least one web foot 16, preferably a plurality of more evenly distributed web feet 16.

Auch sei angeführt, dass die einzelnen Querschnitte der Einsätze 8 nicht unbedingt eine jeweilige rotationssymmetrische Querschnittskontur aufweisen müssen. Vielmehr können die jeweiligen Innenquerschnittskonturen als auch die entsprechenden Außenquerschnittskonturen polygone, beispielsweise dreieckige oder viereckige Verläufe aufweisen.It should also be noted that the individual cross-sections of the inserts 8 need not necessarily have a respective rotationally symmetrical cross-sectional contour. Rather, the respective inner cross-sectional contours as well as the corresponding outer cross-sectional contours may have polygons, for example triangular or quadrangular contours.

Zudem werden ihre wesentlichen funktionale n Konturen K spanend hergestellt. Dabei wird mindestens eine Innenkontur KI des jeweiligen Einsatzes 8 im Tiefbohrverfahren und die Außenkonturen KA des jeweiligen Einsatzes 8 im Drehverfahren hergestellt.In addition, their essential functional contours K are produced by machining. In this case, at least one inner contour K I of the respective insert 8 in the deep drilling method and the outer contours K A of the respective insert 8 are produced in the turning process.

Zusammenfassend ist festzuhalten, dass durch die Erfindung ein Turbulenzerzeuger mit Einsätzen der eingangs genannten Art derart weitergebildet wird, dass er ein deutlich verbessertes Verwendungsspektrum für verschiedenste sortenspezifische Anforderungen aufweist.In summary, it should be noted that the invention provides a turbulence generator with inserts of the type mentioned in such a way that it has a significantly improved range of use for a variety of variety-specific requirements.

BezugszeichenlisteLIST OF REFERENCE NUMBERS

11
Turbulenzerzeugerturbulence generator
22
FaserstoffsuspensionFibrous suspension
33
Turbulenzrohrturbulence tube
44
Lochhole
5.1, 5.25.1, 5.2
Trägerplattesupport plate
66
Führungsteilguide part
77
Stufensprungincrement
88th
Einsatzcommitment
8.18.1
Oberer EinsatzUpper stake
8.28.2
Unterer EinsatzLower stake
99
Stufensprungincrement
1010
Kontraktionsbuchsecontraction socket
1111
Auslaufseiteoutlet side
1212
Innenflächepalm
1313
EndeThe End
1414
Ansatzapproach
1515
Fasechamfer
1616
Stegfußweb foot
ΔA.DELTA.A
QuerschnittsveränderungCross-sectional change
A1 A 1
Erster QuerschnittFirst cross section
A2 A 2
Zweiter QuerschnittSecond cross section
A3 A 3
Querschnittcross-section
DD
Distanzdistance
D14 D 14
Außendurchmesserouter diameter
d3 d 3
RohrinnendurchmesserInside pipe diameter
D8 D 8
EinsatzaußendurchmesserUse of external diameter
d8 d 8
EinsatzinnendurchmesserUse internal diameter
d8 d 8
InnendurchmesserInner diameter
KK
Konturcontour
KA K A
Außenkonturouter contour
KI K i
Innenkonturinner contour
L8 L 8
Einsatzlängeinsert length
LZ L Z
Längelength
Ra R a
Rauhigkeitroughness
SS
Strömungsrichtung (Pfeil)Flow direction (arrow)
TT
Schlankheitsgradslenderness ratio
Z1, Z2 Z 1 , Z 2
Zeilerow

Claims (10)

  1. Turbulence generator (1) for a headbox of a machine for producing a fibrous web, in particular a paper, board or tissue web, from at least one fibrous suspension (2), having a large number of turbulence tubes (3) to guide and distribute the at least one fibrous suspension (2), at least one turbulence tube (3), in the course of the flow of the at least one fibrous suspension (2), changing at least once from a first cross section (A1) to a second cross section (A2), and at least one change in cross section (ΔA) which is in the form of a step (7) being produced by an insert (8) which is arranged in the turbulence tube (3) and has an insert length (L8) and an insert external diameter (D8), the insert (8) having a slenderness ratio (T) in the range from 1:8 to 1:50, preferably from 1:10 to 1:30, and the slenderness ratio (T) being the ratio of insert external diameter (D8) to insert length (L8),
    characterized in that
    the insert (8) has an insert length (L8) which, in the region from 3 to 150 mm, preferably from 5 to 100 mm, is less than the length of the cylindrical or approximately cylindrical part of the turbulence tube (3).
  2. Turbulence generator (1) according to Claim 1,
    characterized in that
    the insert (8) has at least one change in cross section (ΔA) which is formed as a step (9) and, in the course of the flow of the at least one fibrous suspension (2), is arranged at least in the last third, preferably in the last quarter, in particular in the last fifth, of the insert length (L8).
  3. Turbulence generator (1) according to Claim 1 or 2,
    characterized in that
    the insert (8) has a plurality of changes in cross section (ΔA) formed as a respective step (9).
  4. Turbulence generator (1) according to one of the preceding claims,
    characterized in that
    the insert (8) has a total step in relation to the insert length (L8) in the range from 1:10 to 1:100, preferably from 1:12 to 1:75, in particular 1:15 to 1:50, the total step being the difference from the largest insert internal diameter (d8) to insert external diameter (D8).
  5. Turbulence generator (1) according to one of the preceding claims,
    characterized in that
    the insert (8) has a plurality of internal surfaces (12) which have a roughness (Ra) in the range from about 0.4 to about 1.0 µm.
  6. Turbulence generator (1) according to one of the preceding claims,
    characterized in that
    at its end (13) on the inlet side, the insert (8) has a plate-like extension (14), the external diameter (D14) of which is larger than the internal diameter (d3) of the turbulence tube (3), so that the insert (8) is prevented from sliding completely into the turbulence tube (3).
  7. Turbulence generator (1) according to one of the preceding claims,
    characterized in that
    the insert (8) is provided with a chamfer (15) at its end (13) on the inlet side.
  8. Turbulence generator (1) according to one of the preceding claims,
    characterized in that
    along its insert length (L8), the insert (8) has at least one basal web (16) on its outer side, preferably a plurality of in particular uniformly distributed basal webs (16).
  9. Turbulence generator (1) according to one of the preceding claims,
    characterized in that
    the insert (8) consists of a plastic, preferably of a high-performance polymer such as in particular PPSU, PPS, PEI, PTFE or the like.
  10. Turbulence generator (1) according to one of Claims 1 to 8,
    characterized in that
    the insert (8) consists of a corrosion-resistant metal, preferably of stainless steel.
EP06100633A 2005-02-22 2006-01-20 Trailing member for a headbox Not-in-force EP1693507B1 (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE102005008269A DE102005008269A1 (en) 2005-02-22 2005-02-22 Turbulence generator for a headbox

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EP1693507A3 EP1693507A3 (en) 2006-10-04
EP1693507B1 true EP1693507B1 (en) 2009-08-26

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DE102008042032A1 (en) 2008-09-12 2010-03-18 Voith Patent Gmbh Turbulence generator for use in regulator of machine for producing e.g. paper web, has turbulence pipes arranged in gaps and lines for guiding and distribution of material suspension along flow direction and connected with connecting part
DE202008012690U1 (en) 2008-09-24 2008-11-27 Voith Patent Gmbh Guiding device for a headbox of a machine for producing a fibrous web from at least one pulp suspension
DE102009045221A1 (en) 2009-09-30 2011-03-31 Voith Patent Gmbh Headbox turbulizer, headbox, and turbulence generator manufacturing method
DE202009013036U1 (en) 2009-09-30 2010-02-25 Voith Patent Gmbh Guiding device for a headbox of a machine for producing a fibrous web from at least one pulp suspension
DE102009055229A1 (en) 2009-12-23 2011-06-30 Voith Patent GmbH, 89522 Head box for use in sheet forming system of machine for manufacturing material web e.g. paper web, has supply device for supplying fiber suspension, and dosing unit provided for dosing medium into individual channels in plastic modules

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DE19817857A1 (en) * 1998-04-22 1999-10-28 Voith Sulzer Papiertech Patent Turbulence generator in the stock inlet of a papermaking or cardboard production machine
DE10102087A1 (en) * 2001-01-18 2001-06-13 Voith Paper Patent Gmbh Adjustment of fiber orientation in pulp suspension takes place in turbulence generator tube where step changes in cross section have variable separation for flow control
JP3530499B2 (en) * 2001-03-19 2004-05-24 三菱重工業株式会社 Tube bank structure and flow tube manufacturing method

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ATE440996T1 (en) 2009-09-15
DE502006004628D1 (en) 2009-10-08
EP1693507A2 (en) 2006-08-23
EP1693507A3 (en) 2006-10-04
DE102005008269A1 (en) 2006-08-24

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