EP0454989A1 - Vertical former - Google Patents

Vertical former Download PDF

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Publication number
EP0454989A1
EP0454989A1 EP91104493A EP91104493A EP0454989A1 EP 0454989 A1 EP0454989 A1 EP 0454989A1 EP 91104493 A EP91104493 A EP 91104493A EP 91104493 A EP91104493 A EP 91104493A EP 0454989 A1 EP0454989 A1 EP 0454989A1
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EP
European Patent Office
Prior art keywords
formation
former according
vertical former
forming
suction
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.)
Granted
Application number
EP91104493A
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German (de)
French (fr)
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EP0454989B1 (en
Inventor
Alfred Dr. Bubik
Otto Hildebrand
Karl Müller
Jörg Walter
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Voith Sulzer Papiermaschinen GmbH
Original Assignee
Sulzer Escher Wyss GmbH
Escher Wyss GmbH
Voith Sulzer Papiermaschinen GmbH
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Publication of EP0454989A1 publication Critical patent/EP0454989A1/en
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Publication of EP0454989B1 publication Critical patent/EP0454989B1/en
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    • DTEXTILES; PAPER
    • D21PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21FPAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F9/00Complete machines for making continuous webs of paper
    • D21F9/003Complete machines for making continuous webs of paper of the twin-wire type

Definitions

  • the invention relates to a vertical former of a paper machine, in particular for the production of wood-free printing paper and linerboard or testliner, with a twin sieve, the two sieves of which are moved together with the suspension through an essentially vertical formation section, the formation section consisting of at least two formation zones , in each of which a forming element is arranged, which are arranged one behind the other in the direction of movement of the twin wire in the running direction and act on one or the other wire.
  • Such a vertical former is known from US Pat. No. 4,790,909.
  • curved suction boxes are arranged one after the other in the running direction after a forming roller, one suction box on one side and the other suction box offset in the running direction on the other side of the twin wire in order to achieve symmetrical dewatering and thus a symmetrical sheet structure.
  • the drainage takes place at different times, so that the two side areas without a forming element produce a different formation structure.
  • the screens are not guided over long distances, which leads to a wave formation of the screens across the web width and to streaky paper.
  • FI-PS 843 081 shows a vertical former in which a suction former is arranged directly above a vacuum shoe with a certain radium and opposite pressure bars. Another suction box is arranged behind the first-mentioned suction box in the running direction. This results in an uneven distribution of the drainage quantities and an asymmetrical path structure is achieved. Due to the radius of the vacuum shoe and the engagement of the rigid strips directly on top of each other, a very strong initial drainage is achieved, which leads to deformations in the web leads.
  • the invention has for its object to provide a vertical former of the type mentioned, in which an improved formation in connection with an improved web strength and in particular a more uniform web structure can be achieved without streaking.
  • An open forming roll is expediently connected upstream of the formation section.
  • an open forming roller can also be connected downstream of the formation section.
  • These forming rolls are preferably designed as suction rolls.
  • an improved formation in connection with an improved web strength and in connection with a more uniform web structure and smoothness on the surface can be achieved.
  • the formation according to the invention is particularly suitable, also for web weights 80 g / m2.
  • the device according to the invention can also be used in connection with a multi-layer headbox with targeted detection of the white water. Finally, better retention of the fibers is possible during the dewatering process.
  • the one and the other forming elements are expediently arranged opposite one another on different sides of the twin wire.
  • One forming element can be used for further improvement Suction boxes with a formation shoe (grid) and the other forming elements be pressure strips.
  • the suction boxes can expediently have one, two or more suction zones.
  • the water builds up in the suction box parts, and the vacuum is present above the water surface.
  • the vacuum in the different suction zones can be different. If one looks at the negative pressure curve within a part of the suction box along a section transverse to the drainage strips, the water at the top causes the greatest vacuum and decreases from top to bottom as viewed against the direction of travel of the twin wire. This effect is very favorable because it allows the dewatering effect to be dosed so that at the beginning, where the substance drains more easily, the vacuum applied is lower. This affects the formation favorably. A continuous development of the vacuum can be achieved even with finite subdivision of the suction box.
  • the rear formation zone in the running direction of the twin wire can expediently be longer than the front formation zone. This leads to a particularly gentle formation, in particular when the formation shoe of the suction box at the front in the running direction of the twin wire is expediently not curved, i.e. is essentially straight. As a result, the track is treated gently in the first phase of formation and drainage.
  • the vertical former as is shown schematically in FIG. 1, comprises two screens S1 and S2, which converge to form a twin screen in the region of a nozzle 10 which feeds the suspension.
  • This twin wire passes through a formation section or a formation section 12.
  • the twin wire DS is guided around a forming roller 14.
  • the screen S1 is guided around deflection rollers 16 or at the inlet around a closed breast roller 14 '.
  • This forming roller 14 is designed as an open forming roller.
  • the screen S2 is guided around deflection rollers 16 'or 16'', wherein between the breast roll 14 'and the deflection roll 16''the screens S1 and S2 converge to form the double screen DS.
  • the nozzle 10 is directed into this merging nip in order to introduce the aqueous suspension into the nip where a first dewatering takes place.
  • the formation section 12 or the formation section 12 is here divided into two zones, namely a first forming zone Z1 and a second forming zone Z2, the course of the twin wire DS taking place essentially vertically, with a maximum inclination of 30 ° to the vertical.
  • the first formation zone Z1 is preferably shorter than the second formation zone Z2.
  • several zones can also be provided in succession.
  • a forming element is arranged opposite each other on the opposite ends of the twin wire DS in each zone, namely in the first formation zone Z1 on the right-hand side pressure bars 18, which are preferably elastic and, if necessary, adjustable, elastic to the twin wire or to the Sieve S2 in the area of the double sieve DS are pressed to discharge the extracted water via a discharge box 18 '.
  • a suction box 19 On the opposite side, adjacent to the screen S1, there is a suction box 19 with a formation shoe 19 ', which consists of a lattice-like structure with strips and slits extending across the width, as is known in principle.
  • a suction box 21 with a formation shoe 21 ' lies against the screen S2.
  • a forming element is arranged on both sides of the twin wire DS, the opposite forming elements as pressure strips on the one hand and as suction boxes on the other hand being different forming elements, which are however arranged alternately in the direction of movement of the twin wire DS.
  • the formation shoes 19 ', 21' are straight in FIG. 1.
  • the formation section 12 also takes a straight course between the forming rollers 14 'and 14.
  • the formation section or formation section 12 is drawn out in detail in FIG. 2.
  • the suction box 19 is designed here in one stage with a deflection element 19 ′′ and the suction box 21 in two stages with the deflection elements 21 ′′. A clearer representation of this two-stage suction box 21 with the water accumulation 22 can be seen more clearly in FIG. 5 of the accompanying drawing.
  • 3 and 4 each show a double-wire belt curve curved to the left and to the right in the formation section 12, although the formation shoe 19 'is preferably straight in the first formation stage Z1 in order to be able to carry out a more gentle drainage in the first stage.
  • the formation shoe 21 'straight in the second zone Z2 in which case the two formation stages Z1 and Z2 are arranged at a slight angle to one another.
  • the nozzle 10 is aligned so that it directs the suspension from bottom right to top left into the gap where the screens S1 and S2 converge to form the twin screen DS.
  • the screen S2 is guided around the open forming roller 14 '.
  • a three-stage suction box 26 is shown, with a formation shoe 26 ', which is just formed here.
  • the twin wire belt course is indicated by an arrow 27. From the water levels in the drainage water outlet 28 it can be seen that a higher negative pressure prevails in the uppermost section 29 than in the section 30 below and the section 31 still underneath. This means that the suction pressure in the suction box sections corresponds to the direction of movement 27 from bottom to top increases, which also has a positive influence on gentle drainage with regard to an improved formation taking into account the desired web strength and in particular a uniform web structure.
  • troughs 13 are provided for collecting the water extracted from the forming breast rollers 14 '.
  • Fig. 7 shows an embodiment of a vacuum-operated slit suction device in front of an arrangement of pressure strips 34, which are movable substantially vertically to the screen S in accordance with the arrow 36 in order to change the contact pressure of the strips.
  • the slot suction device 32 consists of an inlet part 40 which can likewise be moved essentially perpendicular to the sieve 6 in accordance with the arrow 38 and which forms a gap 44 with the sieve S which preferably converges in the direction of the arrow 42. In this area, very favorable pre-dewatering takes place through the slot 46 under the action of a vacuum acting in the space 48.
  • the slot 46 preferably runs essentially horizontally in a first section after the gap 44 and then essentially vertically and then arrives in a collecting container 50.
  • a collecting container 52 serves to receive the water removed in the area of the pressure strips 34 via collecting plates 60.
  • a suction box 62 is provided for sub-separation after the open forming roll 14 under the screen S2.

Abstract

The invention relates to a vertical former with a vertical double sieve (DS). In the formation section (12), mutually opposite different forming elements (18, 19, 20, 21) are arranged, in order to achieve an improved formation in association with an improved web strength and in particular a more uniform web structure. <IMAGE>

Description

Die Erfindung bezieht sich auf einen Vertikalformer einer Papiermaschine, insbesondere zum Herstellen von holzfreien Druckpapieren und Linerboard bzw. Testliner, mit einem Doppelsieb, dessen beide Siebe gemeinsam mit der Suspension durch einen im wesentlichen vertikalen Formationsabschnitt bewegt werden, wobei der Formationsabschnitt aus mindestens zwei Formationszonen besteht, in denen je ein Formierelement angeordnet ist, die in der Bewegungsrichtung des Doppelsiebes wechselseitig desselben in Laufrichtung hintereinander angeordnet sind und auf das eine bzw. das andere Sieb einwirken.The invention relates to a vertical former of a paper machine, in particular for the production of wood-free printing paper and linerboard or testliner, with a twin sieve, the two sieves of which are moved together with the suspension through an essentially vertical formation section, the formation section consisting of at least two formation zones , in each of which a forming element is arranged, which are arranged one behind the other in the direction of movement of the twin wire in the running direction and act on one or the other wire.

Ein derartiger Vertikalformer ist aus der US-PS 4 790 909 bekannt. Hier sind nach einer Formierwalze gekrümmte Saugkästen wechselseitig in Laufrichtung nacheinanderliegend angeordnet, wobei der eine Saugkasten auf der einen und der andere Saugkasten in Laufrichtung versetzt auf der anderen Seite des Doppelsiebes anliegt, um so eine symmetrische Entwässerung zu erreichen und damit einen symmetrischen Blattaufbau. Die Entwässerung läuft jedoch zeitlich versetzt ab, so daß die beiden Seitenbereiche ohne Formierelement eine unterschiedliche Formationsstruktur bewirken. Außerdem sind die Siebe über weite Strecken nicht geführt, was zu einer Wellenbildung der Siebe über die Bahnbreite und zu streifigem Papier führt.Such a vertical former is known from US Pat. No. 4,790,909. Here, curved suction boxes are arranged one after the other in the running direction after a forming roller, one suction box on one side and the other suction box offset in the running direction on the other side of the twin wire in order to achieve symmetrical dewatering and thus a symmetrical sheet structure. However, the drainage takes place at different times, so that the two side areas without a forming element produce a different formation structure. In addition, the screens are not guided over long distances, which leads to a wave formation of the screens across the web width and to streaky paper.

Der FI-PS 843 081 ist ein Vertikalformer zu entnehmen, bei der ein Saugformer direkt über einem Vakuumschuh mit einem bestimmten Radium und gegenüber Anpreßleisten angeordnet ist. In Laufrichtung hinter dem erstgenannten Saugkasten ist ein weiterer Saugkasten angeordnet. Dadurch erfolgt eine ungleichseitige Verteilung der Entwässerungsmengen, und es wird eine asymmetrische Bahnstruktur erzielt. Durch den Radius des Vakuumschuhes und den Eingriff der starren Leisten direkt aufeinander wird eine sehr starke initiale Entwässerung erzielt, die zu Verdrückungen in der Bahn führt.FI-PS 843 081 shows a vertical former in which a suction former is arranged directly above a vacuum shoe with a certain radium and opposite pressure bars. Another suction box is arranged behind the first-mentioned suction box in the running direction. This results in an uneven distribution of the drainage quantities and an asymmetrical path structure is achieved. Due to the radius of the vacuum shoe and the engagement of the rigid strips directly on top of each other, a very strong initial drainage is achieved, which leads to deformations in the web leads.

Der Erfindung liegt die Aufgabe zugrunde, einen Vertikalformer der eingangs genannten Art zu schaffen, bei dem eine verbesserte Formation in Verbindung mit einer verbesserten Bahnfestigkeit und insbesondere eine gleichmäßigere Bahnstruktur ohne Streifenbildung erzielt werden kann.The invention has for its object to provide a vertical former of the type mentioned, in which an improved formation in connection with an improved web strength and in particular a more uniform web structure can be achieved without streaking.

Diese Aufgabe wird erfindungsgemäß dadurch gelöst, daß hinsichtlich der einen Formierelemente auf der jeweils entgegengesetzten Seite des Doppelsiebes ebenfalls wechselseitig und in Laufrichtung nacheinander andere Formierelemente angeordnet sind, welche die Siebe führen und stützen.This object is achieved in that with respect to the one forming element on the opposite side of the twin wire also other forming elements are arranged alternately and in the running direction, which guide and support the sieves.

Zweckmäßigerweise ist eine offene Formierwalze der Formationsstrecke vorgeschaltet. Es kann aber auch eine offene Formierwalze der Formationsstrecke nachgeschaltet sein. Diese Formierwalzen sind vorzugsweise als Saugwalzen ausgebildet.An open forming roll is expediently connected upstream of the formation section. However, an open forming roller can also be connected downstream of the formation section. These forming rolls are preferably designed as suction rolls.

Es besteht aber auch die Möglichkeit, vor dem ersten Formierelement einen vakuumbeaufschlagten Schlitzsauger vorzusehen.However, there is also the possibility of providing a vacuum suction device before the first forming element.

Durch die erfindungsgemäße Lösung kann eine verbesserte Formation in Verbindung mit einer verbesserten Bahnfestigkeit und in Verbindung mit einer gleichmäßigeren Bahnstruktur und Glätte an der Oberfläche erzielt werden. Die erfindungsgemäße Formation ist besonders gut geeignet, auch für Bahngewichte 80 g/m². Auch ist die erfindungsgemäße Vorrichtung einsetzbar in Verbindung mit einem Mehrschicht-Stoffauflauf bei gezielter Erfassung der Siebwässer. Schließlich ist eine bessere Retention der Fasern beim Entwässerungsvorgang möglich.With the solution according to the invention, an improved formation in connection with an improved web strength and in connection with a more uniform web structure and smoothness on the surface can be achieved. The formation according to the invention is particularly suitable, also for web weights 80 g / m². The device according to the invention can also be used in connection with a multi-layer headbox with targeted detection of the white water. Finally, better retention of the fibers is possible during the dewatering process.

Zweckmäßigerweise sind die einen und die anderen Formierelemente jeweils einander gegenüberliegend auf verschiedenen Seiten des Doppelsiebes angeordnet.The one and the other forming elements are expediently arranged opposite one another on different sides of the twin wire.

Die einen Formierelemente können im Hinblick auf eine weitere Verbesserung Saugkästen mit einem Formationsschuh (Gitter) und die anderen Formierelemente Anpreßleisten sein.One forming element can be used for further improvement Suction boxes with a formation shoe (grid) and the other forming elements be pressure strips.

Die Saugkästen können zweckmäßigerweise eine, zwei oder mehr Saugzonen aufweisen. Bei einer vorteilhaften Ausführungsform (Fig. 5) staut sich in den Saugkastenteilen das Wasse, und das Vakuum liegt oberhalb der Wasseroberfläche an. Dabei kann das Vakuum in den unterschiedlichen Saugzonen unterschiedlich groß sein. Betrachtet man den Unterdruckverlauf innerhalb eines Teiles des Saugkastens entlang einer Strecke quer zu den Entwässerungsleisten, so ist durch das aufgestaute Wasser das Vakuum oben am größten und nimmt gegen die Laufrichtung des Doppelsiebes gesehen von oben nach unten ab. Dieser Effekt ist sehr günstig, weil dadurch die Entwässerungswirkung so dosiert werden kann, daß zu Anfang, wo der Stoff noch leichter entwässert, der angelegte Unterdruck geringer ist. Dadurch wird die Formation günstig beeinflußt. Es kann auch bei endlicher Unterteilung des Saugkastens eine kontinuierliche Entwicklung des Unterdrucks erzielt werden.The suction boxes can expediently have one, two or more suction zones. In an advantageous embodiment (FIG. 5), the water builds up in the suction box parts, and the vacuum is present above the water surface. The vacuum in the different suction zones can be different. If one looks at the negative pressure curve within a part of the suction box along a section transverse to the drainage strips, the water at the top causes the greatest vacuum and decreases from top to bottom as viewed against the direction of travel of the twin wire. This effect is very favorable because it allows the dewatering effect to be dosed so that at the beginning, where the substance drains more easily, the vacuum applied is lower. This affects the formation favorably. A continuous development of the vacuum can be achieved even with finite subdivision of the suction box.

Zweckmäßigerweise kann die in Laufrichtung des Doppelsiebes hintere Formationszone länger ausgebildet sein als die vordere Formationszone. Dies führt zu einer besonders schonenden Formation, insbesondere dann, wenn zweckmäßigerweise der Formationsschuh des in Laufrichtung des Doppelsiebes vorderen Saugkastens nicht gekrümmt, d.h. im wesentlichen gerade ausgebildet ist. Dadurch wird die Bahn in der ersten Phase der Formation und der Entwässerung schonend behandelt.The rear formation zone in the running direction of the twin wire can expediently be longer than the front formation zone. This leads to a particularly gentle formation, in particular when the formation shoe of the suction box at the front in the running direction of the twin wire is expediently not curved, i.e. is essentially straight. As a result, the track is treated gently in the first phase of formation and drainage.

Eine weitere Optimierungsmöglichkeit ergibt sich dadurch, daß die Formierleisten elastisch an das Doppelsieb anpreßbar sind.Another possibility for optimization results from the fact that the forming strips can be pressed elastically onto the twin wire.

Durch die wechselseitige Anordnung unterschiedlicher Formierelemente in mehreren Stufen ist es möglich, asymmetrische Leerseiten zu vermeiden, was einen positiven Einfluß auf eine gleichmäßige und schonend wirksame Formation hat.The mutual arrangement of different forming elements in several stages makes it possible to avoid asymmetrical blank pages, which has a positive influence on a uniform and gently effective formation.

Weitere vorteilhafte Ausgestaltungen ergeben sich aus den Unteransprüchen.Further advantageous embodiments result from the subclaims.

Die Erfindung wird nachfolgend anhand einiger, in den Zeichnungen rein schematisch dargestellten Ausführungsbeispielen näher erläutert. Es zeigt:

Fig. 1
eine schematische Gesamt-Seitenansicht eines Vertikalformers mit einer im wesentlichen geraden Formationsstrecke,
Fig. 2
den Formationsabschnitt alleine,
Fig. 3
ebenfalls den Formationsabschnitt alleine, jedoch mit einer gekrümmten Formationsstrecke,
Fig. 4
ebenfalls den Formationsabschnitt alleine mit einer gegenüber Fig. 3 entgegengesetzt gekrümmten Formationsstrecke, bei der in der ersten Formationszone die Formationsstrecke gerade ist,
Fig. 5
schematisch einen zweistufigen Saugkasten,
Fig. 6
schematisch einen dreistufigen Saugkasten mit einer anderen Wasserabführung und
Fig. 7
in schematischer Ansicht einen vakuumbeaufschlagten Schlitzsauger.
The invention is explained in more detail below with the aid of a few exemplary embodiments shown purely schematically in the drawings. It shows:
Fig. 1
1 shows a schematic overall side view of a vertical former with an essentially straight formation section,
Fig. 2
the formation section alone,
Fig. 3
also the formation section alone, but with a curved formation section,
Fig. 4
likewise the formation section alone with a formation section which is curved opposite to FIG. 3 and in which the formation section is straight in the first formation zone,
Fig. 5
schematically a two-stage suction box,
Fig. 6
schematically a three-stage suction box with a different water drainage and
Fig. 7
a schematic view of a vacuum-operated slot suction device.

Der Vertikalformer, wie er schematisch in Fig. 1 dargestellt ist, umfaßt zwei Siebe S1 und S2, die im Bereich einer die Suspension zuführenden Düse 10 zu einem Doppelsieb zusammenlaufen. Dieses Doppelsieb durchläuft eine Formationsstrecke bzw. einen Formationsabschnitt 12. Am Ausgang dieser Formationsstrecke ist das Doppelsieb DS um eine Formierwalze 14 geführt. Nach dieser Formierwalze 14 ist das Sieb S1 um Umlenkwalzen 16 geführt bzw. am Einlauf um eine geschlossene Brustwalze 14 '. Diese Formierwalze 14 ist als offene Formierwalze ausgebildet.The vertical former, as is shown schematically in FIG. 1, comprises two screens S1 and S2, which converge to form a twin screen in the region of a nozzle 10 which feeds the suspension. This twin wire passes through a formation section or a formation section 12. At the exit of this formation section, the twin wire DS is guided around a forming roller 14. After this forming roller 14, the screen S1 is guided around deflection rollers 16 or at the inlet around a closed breast roller 14 '. This forming roller 14 is designed as an open forming roller.

Das Sieb S2 ist nach der Formierwalze 14 um Umlenkwalzen 16' bzw. 16 '' geführt, wobei zwischen der Brustwalze 14' und der Umlenkwalze 16'' die Siebe S1 und S2 zum Doppelsieb DS zusammenlaufen. In diesen Zusammenlaufspalt ist die Düse 10 gerichtet, um die wässrige Suspension in den Walzenspalt einzuführen, wo eine erste Entwässerung erfolgt.After the forming roller 14, the screen S2 is guided around deflection rollers 16 'or 16'', wherein between the breast roll 14 'and the deflection roll 16''the screens S1 and S2 converge to form the double screen DS. The nozzle 10 is directed into this merging nip in order to introduce the aqueous suspension into the nip where a first dewatering takes place.

Die Formationsstrecke 12 bzw. der Formationsabschnitt 12 ist hier in zwei Zonen, und zwar eine erste Formierzone Z1 und eine zweite Formierzone Z2, aufgeteilt, wobei hier der Verlauf des Doppelsiebes DS im wesentlichen vertikal, maximal mit einer Neigung von 30o zur Vertikalen erfolgt. Vorzugsweise ist die erste Formationszone Z1 kürzer ausgebildet als die zweite Formationszone Z2. Es können natürlich auch mehrere Zonen hintereinander vorgesehen werden. Wichtig ist, daß in jeder Zone einander gegenüberliegend auf den entgegengesetzten Entden des Doppelsiebes DS jeweils ein Formierelement angeordnet ist, und zwar in der ersten Formationszone Z1 auf der rechten Seite Anpreßleisten 18, die vorzugsweise elastisch und gegebenenfalls verstellbar elastisch an das Doppelsieb bzw. an das Sieb S2 im Bereich des Doppelsiebes DS angepreßt sind, um über einen Abführkasten 18' das entzogene Wasser abzuführen. Auf der entgegengesetzten Seite, am Sieb S1 anliegend, befindet sich ein Saugkasten 19 mit einem Formationsschuh 19', welcher aus einem gitterähnlichen Gebilde mit über die Breite durchgehenden Leisten und Schlitzen besteht, wie dies im Prinzip bekannt ist.The formation section 12 or the formation section 12 is here divided into two zones, namely a first forming zone Z1 and a second forming zone Z2, the course of the twin wire DS taking place essentially vertically, with a maximum inclination of 30 ° to the vertical. The first formation zone Z1 is preferably shorter than the second formation zone Z2. Of course, several zones can also be provided in succession. It is important that a forming element is arranged opposite each other on the opposite ends of the twin wire DS in each zone, namely in the first formation zone Z1 on the right-hand side pressure bars 18, which are preferably elastic and, if necessary, adjustable, elastic to the twin wire or to the Sieve S2 in the area of the double sieve DS are pressed to discharge the extracted water via a discharge box 18 '. On the opposite side, adjacent to the screen S1, there is a suction box 19 with a formation shoe 19 ', which consists of a lattice-like structure with strips and slits extending across the width, as is known in principle.

In der zweiten Formationszone Z2 auf der gleichen Seite, wie der Saugkasten 19, befinden sich Anpreßleisten 20 mit einem Wasserabführkasten 20'. Auf der entgegengesetzten Seite liegt am Sieb S2 ein Saugkasten 21 mit einem Formationsschuh 21 ' an. Dies bedeutet, daß in jeder Formationsstufe Z1 und Z2 auf beiden Seiten des Doppelsiebes DS ein Formierelement angeordnet ist, wobei die gegenüberliegenden Formierelemente als Anpreßleisten einerseits und als Saugksten andererseits unterschiedliche Formierelemente sind, die jedoch in der Bewegungsrichtung des Doppelsiebes DS wechselseitig angeordnet sind. Hier sind in Fig. 1 die Formationsschuhe 19', 21', gerade ausgebildet. Auch die Formationsstrecke 12 nimmt einen geraden Verlauf zwischen den Formierwalzen 14' und 14.In the second formation zone Z2 on the same side as the suction box 19, there are pressure strips 20 with a water discharge box 20 '. On the opposite side, a suction box 21 with a formation shoe 21 'lies against the screen S2. This means that in each formation level Z1 and Z2 a forming element is arranged on both sides of the twin wire DS, the opposite forming elements as pressure strips on the one hand and as suction boxes on the other hand being different forming elements, which are however arranged alternately in the direction of movement of the twin wire DS. Here the formation shoes 19 ', 21' are straight in FIG. 1. The formation section 12 also takes a straight course between the forming rollers 14 'and 14.

In Fig. 2 ist die Formierstrecke bzw. der Formationsabschnitt 12 im Detail herausgezeichnet. Ein Unterschied besteht darin, daß die Düse 10 die Suspension von links unten nach rechts oben schräg in den Spalt zwischen den Walzen 14 und 16'' leitet, wodurch der anfängliche Entwässerungsvorgang in abgeänderter Form beeinflußt wird. Der Saugkasten 19 ist hier einstufig mit einem Ablenkelement 19'' und der Saugkasten 21 zweistufig mit den Ablenkelementen 21'' ausgebildet. Eine deutlichere Darstellung dieses zweistufigen Saugkastens 21 mit der Wasseransammlung 22 ist deutlicher der Fig. 5 der beigefügten Zeichnung zu entnehmen.The formation section or formation section 12 is drawn out in detail in FIG. 2. One difference is that the nozzle 10 slants the suspension from bottom left to top right into the nip between the rollers 14 and 16 ", which affects the initial dewatering process in a modified form. The suction box 19 is designed here in one stage with a deflection element 19 ″ and the suction box 21 in two stages with the deflection elements 21 ″. A clearer representation of this two-stage suction box 21 with the water accumulation 22 can be seen more clearly in FIG. 5 of the accompanying drawing.

In Fig. 3 und 4 sind jeweils ein nach links bzw. nach rechts gekrümmter Doppelsiebbandverlauf im Formationsabschnitt 12 dargestellt, wobei allderdings bevorzugt der Formationsschuh 19' in der ersten Formationsstufe Z1 gerade ausgebildet ist, um in der ersten Stufe eine schonendere Entwässerung durchführen zu können. Es besteht allerdings auch die Möglichkeit, den Formationsschuh 21' in der zweiten Zone Z2 ebenfalls gerade auszuführen, wobei dann die beiden Formationsstufen Z1 und Z2 leicht schräg verlaufend im Winkel zueinander angeordnet sind. In beiden Fällen ist die Düse 10 so ausgerichtet, daß sie die Suspension von unten rechts nach oben links in den Spalt richtet, wo die Siebe S1 und S2 zum Doppelsieb DS zusammenlaufen. In diesem Fall ist das Sieb S2 um die offene Formierwalze 14' geführt.3 and 4 each show a double-wire belt curve curved to the left and to the right in the formation section 12, although the formation shoe 19 'is preferably straight in the first formation stage Z1 in order to be able to carry out a more gentle drainage in the first stage. However, there is also the possibility of also carrying out the formation shoe 21 'straight in the second zone Z2, in which case the two formation stages Z1 and Z2 are arranged at a slight angle to one another. In both cases, the nozzle 10 is aligned so that it directs the suspension from bottom right to top left into the gap where the screens S1 and S2 converge to form the twin screen DS. In this case, the screen S2 is guided around the open forming roller 14 '.

In Fig. 6 ist ein dreistufiger Saugkasten 26 dargestellt, und zwar mit einem Formationsschuh 26', der hier gerade ausgebildet ist. Der Doppelsiebbandverlauf ist durch einen Pfeil 27 gekennzeichnet. Aus den Wasserstandshöhen im Entwässerungswasserablauf 28 ist zu entnehmen, daß in der obersten Sektion 29 ein höherer Unterdruck herrscht als in der darunterliegenden Sektion 30 und der weiterhin darunterliegenden Sektion 31. Dies bedeutet, daß der Saugdruck in den Saugkastensektionen entsprechend der Bewegungsrichtung 27 von unten nach oben zunimmt, was ebenfalls einen positiven Einfluß auf eine schonende Entwässerung hat im Hinblick auf eine verbesserte Formation unter Berücksichtigung der gewünschten Bahnfestigkeit und insbesondere einer gleichmäßigen Bahnstruktur.6, a three-stage suction box 26 is shown, with a formation shoe 26 ', which is just formed here. The twin wire belt course is indicated by an arrow 27. From the water levels in the drainage water outlet 28 it can be seen that a higher negative pressure prevails in the uppermost section 29 than in the section 30 below and the section 31 still underneath. This means that the suction pressure in the suction box sections corresponds to the direction of movement 27 from bottom to top increases, which also has a positive influence on gentle drainage with regard to an improved formation taking into account the desired web strength and in particular a uniform web structure.

Es sei noch vermerkt, daß gemäß der Darstellung in Fig. 2,3 und 4 zum Auffangen des von den Formierbrustwalzen 14' entzogenen Wassers Wannen 13 vorgesehen sind.It should also be noted that, as shown in FIGS. 2, 3 and 4, troughs 13 are provided for collecting the water extracted from the forming breast rollers 14 '.

Fig. 7 zeigt eine Ausführung eines vakuumbeaufschlagten Schlitzsaugers vor einer Anordnung von Anpreßleisten 34, die im wesentlichen senkreicht zum Sieb S entsprechend dem Pfeil 36 bewegbar sind, um den Anpreßdruck der Leisten zu verändern. Der Schlitzsauger 32 besteht aus einem ebenfalls entsprechend dem Pfeil 38 im wesentlichen senkrecht zum Sieb 6 bewegbaren Einlaufteil 40, welches zum Sieb S einen vorzugsweise in Richtung des Pfeiles 42 konvergierenden Spalt 44 bildet. In diesem Bereich erfolgt eine sehr günstige Vorentwässerung durch den Schlitz 46 unter Einwirkung eines im Raum 48 wirkenden Vakuums. Vorzugsweise verläuft der Schlitz 46 in einem ersten Abschnitt nach dem Spalt 44 im wesentlichen horizontal und danach im wesentlichen vertikal und gelangt dann in einen Auffangbehälter 50. Ein Auffangbehälter 52 dient der Aufnahme des im Bereich der Anpreßleisten 34 entnommenen Wassers über Auffangbleche 60.Fig. 7 shows an embodiment of a vacuum-operated slit suction device in front of an arrangement of pressure strips 34, which are movable substantially vertically to the screen S in accordance with the arrow 36 in order to change the contact pressure of the strips. The slot suction device 32 consists of an inlet part 40 which can likewise be moved essentially perpendicular to the sieve 6 in accordance with the arrow 38 and which forms a gap 44 with the sieve S which preferably converges in the direction of the arrow 42. In this area, very favorable pre-dewatering takes place through the slot 46 under the action of a vacuum acting in the space 48. The slot 46 preferably runs essentially horizontally in a first section after the gap 44 and then essentially vertically and then arrives in a collecting container 50. A collecting container 52 serves to receive the water removed in the area of the pressure strips 34 via collecting plates 60.

In Fig. 4 ist nach der offenen Formierwalze 14 unter dem Sieb S2 ein Saugkasten 62 zur Subtrennung vorgesehen.In Fig. 4, a suction box 62 is provided for sub-separation after the open forming roll 14 under the screen S2.

Claims (14)

Vertikalformer einer Papiermaschine, insbesondere zum Herstellen von holzfreien Druckpapieren und Linerboard bzw. Testliner mit einem Doppelsieb (DS), dessen beide Siebe (51,52) gemeinsam mit der Suspension durch einen im wesentlichen vertikalen Formationsabschnitt (12) bewegt werden, wobei der Formationsabschnitt (12) aus mindestens zwei Formationszonen (Z1, Z2) besteht, in denen je ein Formierelement (19,21) angeordnet ist, die in der Laufrichtung des Doppelsiebes (DS) von unten nach oben wechselseitig desselben in Laufrichtung nacheinander angeordnet sind und auf das eine bzw. das andere Sieb einwirken, dadurch gekennzeichnet, daß hinsichtlich der einen Formierelemente (19,21) auf der jeweils entgegengesetzten Seite des Doppelsiebes (DS) ebenfalls wechselseitig und in Laufrichtung nacheinander andere Formierelemente (18,20) angeordnet sind.Vertical former of a paper machine, in particular for producing wood-free printing paper, and a liner board or test liner with a double sieve (DS), the two sieves (51, 52) of which are moved together with the suspension through an essentially vertical formation section (12), the formation section ( 12) consists of at least two formation zones (Z1, Z2), in each of which a forming element (19, 21) is arranged, which are arranged one after the other in the running direction of the twin wire (DS) from bottom to top, one after the other or act on the other sieve, characterized in that, with respect to the one forming element (19, 21), on the opposite side of the double sieve (DS), other forming elements (18, 20) are also arranged alternately and in the running direction. Vertikalformer nach Anspruch 1, dadurch gekennzeichnet, daß die einen (19, 21) und die anderen Formierelemente (18,20) jeweils einander gegenüberliegend angeordnet sind.Vertical former according to Claim 1, characterized in that the one (19, 21) and the other forming elements (18, 20) are each arranged opposite one another. Vertikalformer nach Anspruch 1 oder 2, dadurch gekennzeichnet, daß die einen Formierelemente (19,21) Saugkästen mit einem Formationsschuh (19', 21 ') und die anderen Formierelemente (18,20) Anpreßleisten sind.Vertical former according to claim 1 or 2, characterized in that the one forming elements (19, 21) suction boxes with a formation shoe (19 ', 21') and the other forming elements (18, 20) are pressure strips. Vertikalformer nach Anspruch 3, dadurch gekennzeichnet, daß der Formationsschuh mit von Formierleisten gebildeten Gitterrosten am Doppelsieb (DS) anliegt.Vertical former according to claim 3, characterized in that the formation shoe rests on the double sieve (DS) with gratings formed by forming strips. Vertikalformer nach Anspruch 3, dadurch gekennzeichnet, daß der Saugkasten (21) mindestens zwei Saugzonen aufweist.Vertical former according to claim 3, characterized in that the suction box (21) has at least two suction zones. Vertikalformer nach Anspruch 5, dadurch gekennzeichnet, daß in den Saugzonen (29,30,31) unterschiedlich große Unterdrücke herrschen, und zwar von oben nach unten abnehmend.Vertical former according to claim 5, characterized in that the suction zones (29, 30, 31) have different pressures, decreasing from top to bottom. Vertikalformer nach Anspruch 1, dadurch gekennzeichnet, daß die in Laufrichtung des Doppelsiebes hintere Formationszone (Z2) länger ausgebildet ist als die vordere Formationszone (Z1).Vertical former according to claim 1, characterized in that the rear formation zone (Z2) in the running direction of the twin wire is longer than the front formation zone (Z1). Vertikalformer nach Anspruch 3, dadurch gekennzeichnet, daß der Formationsschuh des in Laufrichtung des Doppelsiebes vorderen Saugkastens (19) im wesentlichen gerade ausgebildet ist.Vertical former according to claim 3, characterized in that the formation shoe of the suction box (19) at the front in the running direction of the twin wire is essentially straight. Vertikalformer nach Anspruch 3, dadurch gekennzeichnet, daß die Anpreßleisten (18,20) elastisch anpreßbar sind.Vertical former according to claim 3, characterized in that the pressure strips (18, 20) can be pressed elastically. Vertikalformer nach Anspruch 1,2 oder 3, dadurch gekennzeichnet, daß eine offene Formierbrustwalze (14 ') der Formationsstrecke (12) vorgeschaltet ist.Vertical former according to Claim 1, 2 or 3, characterized in that an open forming breast roll (14 ') is connected upstream of the formation section (12). Vertikalformer nach Anspruch 1,2 oder 3, dadurch gekennzeichnet, daß eine offene Formierwalze (14) der Formationsstrecke (12) nachgeschaltet ist.Vertical former according to claim 1, 2 or 3, characterized in that an open forming roller (14) is connected downstream of the formation section (12). Vertikalformer nach Anspruch 10, dadurch gekennzeichnet, daß die offene Formierbrustwalze (14 ') als Saugwalze ausgebildet ist.Vertical former according to claim 10, characterized in that the open forming breast roller (14 ') is designed as a suction roller. Vertikalformer nach Anspruch 11, dadurch gekennzeichnet, daß die offene Formierwalze (14) als Saugwalze ausgebildet ist.Vertical former according to claim 11, characterized in that the open forming roller (14) is designed as a suction roller. Vertikalformer nach Anspruch 1,2 oder 3, dadurch gekennzeichnet, daß vor dem ersten Formierelement (18) ein vakuumbeaufschlagter Schlitzsauger (32) angebracht ist.Vertical former according to claim 1, 2 or 3, characterized in that a vacuum-operated slot suction device (32) is attached in front of the first forming element (18).
EP91104493A 1990-05-04 1991-03-22 Vertical former Expired - Lifetime EP0454989B1 (en)

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DE4014403 1990-05-04
DE4014403A DE4014403C2 (en) 1990-05-04 1990-05-04 Vertical former

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EP0454989A1 true EP0454989A1 (en) 1991-11-06
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Cited By (6)

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EP0504123A1 (en) * 1991-03-15 1992-09-16 Valmet Paper Machinery Inc. Twin-wire web former in a paper machine
WO1996011734A1 (en) * 1994-10-14 1996-04-25 Andritz-Patentverwaltungs-Gesellschaft Mbh Device for dewatering and/or washing suspensions, in particular suspensions of fibrous materials
US5833809A (en) * 1994-08-31 1998-11-10 Valmet Corporation Twin-wire former
EP1319745A1 (en) * 2001-12-12 2003-06-18 Voith Paper Patent GmbH Twin-wire former
US7067042B2 (en) 2001-03-13 2006-06-27 Voith Paper Patent Gmbh Twin wire former
EP1696074A1 (en) * 2005-02-24 2006-08-30 Voith Paper Patent GmbH Twin-wire former for producing a fibrous web

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FI920228A0 (en) * 1992-01-17 1992-01-17 Valmet Paper Machinery Inc BANFORMNINGSPARTI FOER PAPPERSMASKIN.
DE4301103C1 (en) * 1993-01-18 1994-08-18 Voith Gmbh J M Screen section of a paper machine
DE19651241A1 (en) * 1996-12-10 1998-06-18 Voith Sulzer Papiermasch Gmbh Double fourdrinier pulp water extraction
DE19652485A1 (en) * 1996-12-17 1998-06-18 Voith Sulzer Papiermasch Gmbh Paper-making machine fourdrinier section
FI109299B (en) * 2001-01-22 2002-06-28 Metso Paper Inc Twin
DE102008040948A1 (en) 2008-08-01 2010-02-04 Voith Patent Gmbh Twin-wire former for a machine for producing a fibrous web

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EP0504123A1 (en) * 1991-03-15 1992-09-16 Valmet Paper Machinery Inc. Twin-wire web former in a paper machine
US5599427A (en) * 1991-03-15 1997-02-04 Valmet Corporation Twin-wire web former in a paper machine
US5833809A (en) * 1994-08-31 1998-11-10 Valmet Corporation Twin-wire former
WO1996011734A1 (en) * 1994-10-14 1996-04-25 Andritz-Patentverwaltungs-Gesellschaft Mbh Device for dewatering and/or washing suspensions, in particular suspensions of fibrous materials
US5868903A (en) * 1994-10-14 1999-02-09 Andritz-Patentverwaltungs-Gesellschaft M.B.H. Device for dewatering and/or washing suspensions, in particular suspensions of fibrous materials
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EP1696074A1 (en) * 2005-02-24 2006-08-30 Voith Paper Patent GmbH Twin-wire former for producing a fibrous web

Also Published As

Publication number Publication date
DE4014403C2 (en) 1994-03-10
CA2040999A1 (en) 1991-11-05
DE4014403A1 (en) 1991-11-07
DE59104927D1 (en) 1995-04-20
ATE119956T1 (en) 1995-04-15
EP0454989B1 (en) 1995-03-15

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