EP1136619B1 - Pressing arrangement - Google Patents

Pressing arrangement Download PDF

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Publication number
EP1136619B1
EP1136619B1 EP01101207A EP01101207A EP1136619B1 EP 1136619 B1 EP1136619 B1 EP 1136619B1 EP 01101207 A EP01101207 A EP 01101207A EP 01101207 A EP01101207 A EP 01101207A EP 1136619 B1 EP1136619 B1 EP 1136619B1
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EP
European Patent Office
Prior art keywords
belt
fibrous web
press
roll
dewatering
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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.)
Expired - Lifetime
Application number
EP01101207A
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German (de)
French (fr)
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EP1136619A3 (en
EP1136619A2 (en
Inventor
Gerhard Kotitschke
Wolfgang Mayer
Roland Mayer
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Voith Patent GmbH
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Voith Paper Patent GmbH
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Priority claimed from DE2000112148 external-priority patent/DE10012148A1/en
Application filed by Voith Paper Patent GmbH filed Critical Voith Paper Patent GmbH
Publication of EP1136619A2 publication Critical patent/EP1136619A2/en
Publication of EP1136619A3 publication Critical patent/EP1136619A3/en
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Publication of EP1136619B1 publication Critical patent/EP1136619B1/en
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    • DTEXTILES; PAPER
    • D21PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21FPAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F3/00Press section of machines for making continuous webs of paper
    • D21F3/02Wet presses
    • D21F3/04Arrangements thereof
    • D21F3/045Arrangements thereof including at least one extended press nip
    • DTEXTILES; PAPER
    • D21PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21FPAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F3/00Press section of machines for making continuous webs of paper
    • D21F3/02Wet presses

Definitions

  • the invention relates to a press arrangement with at least one press nip formed by two press rolls for dewatering a paper, board, tissue or other fibrous web through which a dewatering belt for receiving the squeezed water is guided on both sides in addition to the fibrous web, wherein the fibrous web after the Pressing gap is guided in a common guide path of the two dewatering belts, the below the fibrous web extending lower dewatering belt wraps together with the fibrous web at the end of the guide an evacuated separation roller, the above the fibrous web arranged upper dewatering in the separation roller in an isolation distance from the fibrous web led away and the fibrous web is subsequently taken over by a removal belt according to the preamble of claim 1.
  • Such a pressing arrangement is known for example from DE-U-29800330.
  • the object of the invention is therefore, the leadership of the fibrous web, in particular after the separation distance d. H. to improve the routing of the upper drainage band.
  • the object has been solved by the features of claim 1.
  • the relatively large wrap angle leads to a rapidly widening gusset between fibrous web and upper dewatering belt, which allows the influx of air without the risk of web flutter.
  • the wrap angle is at least 45 °, preferably even at least 60 °.
  • the residence time of the fibrous web in the separation section should be greater than 1 ms, preferably greater than 15 ms. This then allows the routing of the upper dewatering belt without the risk of plucking with respect to the fibrous web.
  • the upper dewatering belt should be performed after the separation distance to a, this dewatering belt deflecting guide roll, and it is advantageous if the unsupported course of the dewatering belt between separation roller and guide roller as short as possible and between 20 and 200 mm, preferably between 20 and 80 mm long. As a result, there is a reduction in the flow of air in the gusset which impedes the guidance of the fibrous web at the lower drainage band.
  • the location of the guide roll of the upper drainage tape should changeable and about a wrap angle of the upper dewatering belt with respect to the separation roller of the lower dewatering belt between 0 and 5 ° be adjustable.
  • the angle between the common guide path (sandwich guide) adjoining the press nip and the press plane formed by the press rolls should preferably be variable in the range of ⁇ 5 °. If the sandwich guide increases, this is associated with a more intensive drainage downwards and thus a greater compression of the underside of the fibrous web. A sloping sandwich guide, however, leads to a more intensive drainage upwards and thus to a greater compression of the top. This offers an effective means of influencing the two-sidedness of the fibrous web, in particular with regard to surface strength, oil absorption and printability.
  • the aim of the invention is to avoid long, straight sandwich guides of dewatering belt and fibrous web.
  • the lower band can also be designed as a plastic band with largely closed, dense surface. In this case, instead of the vacuumed Trenwalze a normal guide roller is used. A relatively smooth surface ensures the adhesion of the fibrous web at the lower band.
  • the fibrous web runs together with the lower dewatering belt from the separation roller to a spaced, looped by the air-permeable collection tape and suction removal roll, where the fibrous web is taken over by the removal belt.
  • the clear distance between the separation roller and the take-off roll should be as small as possible and is between 20 and 200 mm, in particular between 20 and 80 mm. Because of the short distance between separation and take-off roll can in this area on web stabilizers and additional blowing or suction be waived. In addition, this also leads to the shortening of the gusset and thus to reduce the attack surface of the fibrous web.
  • the lower dewatering belt wraps around an adjustable guide roller after the transfer of the fibrous web and a gap, a contact or a wrap of the lower dewatering belt with respect to the take-off roller is adjustable via this guide roller. This allows, for example, for safely transferring the fibrous web to form a relatively large wrap angle.
  • the accepting band has a higher speed than the lower dewatering band.
  • the removal belt may be formed as a press felt of a following press nip, as a transfer belt for onward transport or as a dryer wire of a following drying group for drying the fibrous web.
  • the distance between the guide roller of the upper dewatering belt and the take-off belt should be adjustable in order thus to control the entrained air in the gusset.
  • both dewatering belts should be formed as a press felt.
  • Particularly suitable is the press arrangement at web speeds of the fibrous web of more than 1500 m / min.
  • FIG. 1 shows a schematic cross section through a press arrangement according to the invention for dewatering a fibrous web 1, in particular a paper web.
  • a dewatering belt 2, 3 in the form of an air-permeable press felt for receiving and for transporting the squeezed out water is guided on both sides next to the fibrous web 1.
  • the upper press roll 11 has a flexible roll shell which runs over a pressure shoe with concave contact surface.
  • this guide section 4 should be as short as possible.
  • the lower dewatering belt 3 which extends below the fibrous web 1, wraps around together with the fibrous web 1 an evacuated separating roller 5 with a wrap angle 8 of approximately 60 °.
  • the outgoing from the negative pressure of the separation roller 5 increased adhesion of the fibrous web 1 allows the solution and subsequent removal of the upper drainage belt 2 of the fibrous web 1 in a separation section 6.
  • This separation section 6 forms the end of the common guide section 4, wherein the residence time of the fibrous web 1 in the Isolation distance 6 is between 1 and 5 ms.
  • the upper dewatering belt 2 is guided after the separating line 6 to a guide roller 9, the position of which can be changed in the vertical direction, so that a slight looping of the upper dewatering belt 2 of 0-5 ° can be set on the separating roller 5.
  • the free, unsupported course of the dewatering belt 2 between separation 5 and guide roller 9 is smaller than 80 mm. The shortening of the gusset limits the, affecting the leadership of the fibrous web 1 affecting air flow in the gusset.
  • the fibrous web 1 runs together with the lower dewatering belt 3 to a, from an air-permeable removal belt 7 looped and evacuated pickup roller 10.
  • the negative pressure of the pickup roller 10 supports the transfer of the fibrous web 1 from the lower dewatering belt 3 to the removal belt 7. Zur Limiting the vulnerable area in which the fibrous web 1 runs together with the lower dewatering belt 3 between separation and take-off roll 10 without web stabilizers, suction or blowing devices, the clear, that is the shortest distance between separation 5 and take-off roll 10 is less than 80 mm.
  • the removal belt 7 runs slightly faster than the lower dewatering belt 3. This train is so small that no negative effects on the web guide are to be expected. It depends on the moisture elongation of the fibrous web 1, the machine speed and the elongation in the dryer section. It should be approx. 0.5 - 1.0% between two presses and approx. 2.5 - 4.0% between the last press and the dryer section.
  • the lower dewatering belt 3 is guided over the transfer of the fibrous web 1 via an adjustable guide roller 13. By their adjustment, a wrap of the take-off roll 10 can be achieved, which can be of advantage when transferring the fibrous web 1. After the transfer can then again a contact or a gap between the lower Dewatering belt 3 and the take-off roller 10 are set with the removal belt 7.
  • the height-adjustable guide roller 9 of the upper dewatering belt 2 makes it possible to influence the gap between this guide roller 9 and the removal belt 7 and thus the entrained air in the gusset.
  • the removal belt 7 may be formed as a press felt of a subsequent press nip or as a dryer wire of a following drying group.
  • the evacuated rolls have a perforated roll shell, the interior of which is connected to a vacuum source.
  • the evacuated region of the guide rolls in its extension transversely to the fibrous web 1 can be changed and / or subdivided into separately controllable negative-pressure zones.
  • the web edges of the fibrous web 1 due to the increased risk of lifting should be assigned separate high vacuum zones.

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  • Paper (AREA)
  • Auxiliary Devices For And Details Of Packaging Control (AREA)
  • Press Drives And Press Lines (AREA)
  • Glass Compositions (AREA)

Abstract

Pressing arrangement having two press rolls forming at least one press nip for dewatering a web, and two dewatering belts arranged to be guided through the at least one press nip with the web. The dewatering belts positioned on opposite sides of the web to absorb water. A common guidance path, formed by the dewatering belts guiding the web, is located after the at least one press nip. A separating roll and a lower one of the dewatering belts is arranged to wrap the separating roll along with the web at an end of the common guidance path. An upper one of the dewatering belts is arranged to be guided away from the web in a separation path in a region of the separating roll. Lower dewatering belt and web wrap the separating roll subsequent to the separation path at a wrapping angle of at least about 30°.

Description

Die Erfindung betrifft eine Pressanordnung mit zumindest einem von zwei Presswalzen gebildeten Preßspalt zur Entwässerung einer Papier-, Karton-, Tissue- oder anderen Faserstoffbahn, durch den neben der Faserstoffbahn beidseitig je ein Entwässerungsband zur Aufnahme des ausgepressten Wassers geführt wird, wobei die Faserstoffbahn nach dem Preßspalt in einer gemeinsamen Führungsstrecke von beiden Entwässerungsbändern geführt wird, das unterhalb der Faserstoffbahn verlaufende untere Entwässerungsband zusammen mit der Faserstoffbahn am Ende der Führungsstrecke eine besaugte Trennwalze umschlingt, das oberhalb der Faserstoffbahn angeordnete, obere Entwässerungsband im Bereich der Trennwalze in einer Trennstrecke von der Faserstoffbahn weggeführt und die Faserstoffbahn anschließend von einem Abnahmeband übernommen wird nach dem Oberbegriff des Anspruchs 1.The invention relates to a press arrangement with at least one press nip formed by two press rolls for dewatering a paper, board, tissue or other fibrous web through which a dewatering belt for receiving the squeezed water is guided on both sides in addition to the fibrous web, wherein the fibrous web after the Pressing gap is guided in a common guide path of the two dewatering belts, the below the fibrous web extending lower dewatering belt wraps together with the fibrous web at the end of the guide an evacuated separation roller, the above the fibrous web arranged upper dewatering in the separation roller in an isolation distance from the fibrous web led away and the fibrous web is subsequently taken over by a removal belt according to the preamble of claim 1.

Eine derartige Pressanordnung ist beispielsweise aus DE-U-29800330 bekannt.Such a pressing arrangement is known for example from DE-U-29800330.

Derartige Anordnungen sind seit langem bekannt, wobei die Faserstoffbahn nach dem Wegführen des oberen Entwässerungsbandes mit Hilfe von Saug-und/oder Blaseinrichtungen am unteren Entwässerungsband gehalten wird. Mit zunehmender Bahngeschwindigkeit, steigendem Wassergehalt im Entwässerungsband sowie wachsendem Verschleiß des Entwässerungsbandes nimmt die Wirkung, insbesondere der Saugeinrichtungen auf die Faserstoffbahn ab. Im Ergebnis verringert sich die Haftung der Faserstoffbahn am unteren Entwässerungsband, was wiederum zum Flattern der Bahnränder und somit zur verstärkten Dehnung der Bahnränder führen kann.Such arrangements have long been known, wherein the fibrous web is held after the removal of the upper dewatering belt by means of suction and / or blowing devices on the lower dewatering belt. With increasing web speed, increasing water content in the dewatering belt and increasing wear of the dewatering belt, the effect, in particular of the suction devices on the fibrous web decreases. As a result, the adhesion of the fibrous web to the lower dewatering belt decreases, which in turn can cause fluttering of the web edges and thus increased stretch of the web edges.

Außerdem strömt nach der Trennstrecke Luft in den Zwickel zwischen der Faserstoffbahn und dem oberen Entwässerungsband. Auch diese Luftströmung kann zum Abheben der Bahnränder und zur Faltenbildung führen.In addition, after the separation section, air flows into the gusset between the fibrous web and the upper dewatering belt. This air flow can lead to the lifting of the web edges and wrinkles.

Die Aufgabe der Erfindung ist es daher, die Führung der Faserstoffbahn insbesondere nach der Trennstrecke d. h. der Wegführung des oberen Entwässerungsbandes zu verbessern.The object of the invention is therefore, the leadership of the fibrous web, in particular after the separation distance d. H. to improve the routing of the upper drainage band.

Erfindungsgemäß wurde die Aufgabe durch die Merkmale des Anspruchs 1 gelöst. Der relativ große Umschlingungswinkel führt zu einem sich schnell verbreiternden Zwickel zwischen Faserstoffbahn und oberen Entwässerungsband, was das Einströmen von Luft ohne die Gefahr von Bahnflattern ermöglicht. Mit Vorteil beträgt der Umschlingungswinkel mindestens 45 °, vorzugsweise sogar mindestens 60 °.According to the invention the object has been solved by the features of claim 1. The relatively large wrap angle leads to a rapidly widening gusset between fibrous web and upper dewatering belt, which allows the influx of air without the risk of web flutter. Advantageously, the wrap angle is at least 45 °, preferably even at least 60 °.

Eine besaugte Trennwalze verstärkt durch den auf die Faserstoffbahn wirkenden Unterdruck im gesamten umschlungenen Bereich die Haftung der Faserstoffbahn am unteren, luftdurchlässigen Entwässerungsband. Damit sich die Haftung der Faserstoffbahn am unteren Entwässerungsband in ausreichendem Umfang erhöhen und gegenüber dem oberen Entwässerungsband genügend verringern kann, sollte die Verweilzeit der Faserstoffbahn in der Trennstrecke größer als 1 ms, vorzugsweise größer als 15 ms sein. Dies erlaubt anschließend die Wegführung des oberen Entwässerungsbandes ohne die Gefahr des Zupfens bezüglich der Faserstoffbahn.An evacuated separation roller reinforced by the negative pressure acting on the fibrous web in the entire looped area, the adhesion of the fibrous web to the lower, air-permeable drainage tape. In order that the adhesion of the fibrous web to the lower dewatering belt can increase to a sufficient extent and can decrease sufficiently compared to the upper dewatering belt, the residence time of the fibrous web in the separation section should be greater than 1 ms, preferably greater than 15 ms. This then allows the routing of the upper dewatering belt without the risk of plucking with respect to the fibrous web.

Um die Länge des Zwickels zwischen dem oberen und dem unteren Entwässerungsband stark zu begrenzen, sollte das obere Entwässerungsband nach der Trennstrecke zu einer, dieses Entwässerungsband umlenkenden Leitwalze geführt werden, wobei es vorteilhaft ist, wenn der ungestützte Verlauf des Entwässerungsbandes zwischen Trennwalze und Leitwalze möglichst kurz und zwischen 20 und 200 mm, vorzugsweise zwischen 20 und 80 mm lang ist. Im Ergebnis kommt es zu einer Verringerung der, die Führung der Faserstoffbahn am unteren Entwässerungsband beeinträchtigenden Luftströmung in den Zwickel. Außerdem sollte die Lage der Leitwalze des oberen Entwässerungsbandes veränderbar und darüber ein Umschlingungswinkel des oberen Entwässerungsbandes bezüglich der Trennwalze des unteren Entwässerungsbandes zwischen 0 und 5 ° einstellbar sein.In order to limit the length of the gusset between the upper and lower dewatering band strong, the upper dewatering belt should be performed after the separation distance to a, this dewatering belt deflecting guide roll, and it is advantageous if the unsupported course of the dewatering belt between separation roller and guide roller as short as possible and between 20 and 200 mm, preferably between 20 and 80 mm long. As a result, there is a reduction in the flow of air in the gusset which impedes the guidance of the fibrous web at the lower drainage band. In addition, the location of the guide roll of the upper drainage tape should changeable and about a wrap angle of the upper dewatering belt with respect to the separation roller of the lower dewatering belt between 0 and 5 ° be adjustable.

Des weiteren sollte auch der Winkel zwischen der sich an den Presspalt anschließenden gemeinsamen Führungsstrecke (Sandwichführung) und der von den Presswalzen gebildeten Pressebene vorzugsweise im Bereich von ± 5 ° variierbar sein. Verläuft die Sandwichführung ansteigend, so ist dies mit einer intensiveren Entwässerung nach unten und damit einer stärkeren Verdichtung der Unterseite der Faserstoffbahn verbunden. Eine abfallende Sandwichführung führt dagegen zu einer intensiveren Entwässerung nach oben und damit zu einer stärkeren Verdichtung der Oberseite. Dies bietet ein wirksames Mittel zur Beeinflussung der Zweiseitigkeit der Faserstoffbahn insbesondere hinsichtlich Oberflächenfestigkeit, Ölaufnahme und Bedruckbarkeit.Furthermore, the angle between the common guide path (sandwich guide) adjoining the press nip and the press plane formed by the press rolls should preferably be variable in the range of ± 5 °. If the sandwich guide increases, this is associated with a more intensive drainage downwards and thus a greater compression of the underside of the fibrous web. A sloping sandwich guide, however, leads to a more intensive drainage upwards and thus to a greater compression of the top. This offers an effective means of influencing the two-sidedness of the fibrous web, in particular with regard to surface strength, oil absorption and printability.

Ziel der Erfindung ist es, lange, gerade Sandwichführungen von Entwässerungsband und Faserstoffbahn zu vermeiden. Das untere Band kann auch als Kunststoffband mit weitestgehend geschlossener, dichter Oberfläche ausgeführt sein. In diesem Fall kommt statt der besaugten Trenwalze eine normale Leitwalze zum Einsatz. Eine relativ glatte Oberfläche gewährleistet dabei die Haftung der Faserstoffbahn am unteren Band.The aim of the invention is to avoid long, straight sandwich guides of dewatering belt and fibrous web. The lower band can also be designed as a plastic band with largely closed, dense surface. In this case, instead of the vacuumed Trenwalze a normal guide roller is used. A relatively smooth surface ensures the adhesion of the fibrous web at the lower band.

Für den weiteren sicheren Lauf der Faserstoffbahn ist es von Vorteil, wenn die Faserstoffbahn gemeinsam mit dem unteren Entwässerungsband von der Trennwalze zu einer davon beabstandeten, von dem luftdurchlässigen Abnahmeband umschlungenen und besaugten Abnahmewalze läuft, wo die Faserstoffbahn vom Abnahmeband übernommen wird. Dabei sollte der lichte Abstand zwischen der Trennwalze und der Abnahmewalze möglichst klein sein und liegt zwischen 20 und 200 mm, insbesondere zwischen 20 und 80 mm. Wegen der kurzen Strecke zwischen Trenn- und Abnahmewalze kann in diesem Bereich auf Bahnstabilisatoren und zusätzliche Blas- oder Saugeinrichtungen verzichtet werden. Außerdem führt dies auch zur Verkürzung des Zwickels und somit zur Verringerung der Angriffsfläche der Faserstoffbahn.For the further safe running of the fibrous web, it is advantageous if the fibrous web runs together with the lower dewatering belt from the separation roller to a spaced, looped by the air-permeable collection tape and suction removal roll, where the fibrous web is taken over by the removal belt. The clear distance between the separation roller and the take-off roll should be as small as possible and is between 20 and 200 mm, in particular between 20 and 80 mm. Because of the short distance between separation and take-off roll can in this area on web stabilizers and additional blowing or suction be waived. In addition, this also leads to the shortening of the gusset and thus to reduce the attack surface of the fibrous web.

Es ist auch von Vorteil, wenn das untere Entwässerungsband nach der Übergabe der Faserstoffbahn eine verstellbare Leitwalze umschlingt und über diese Leitwalze ein Spalt, ein Kontakt oder eine Umschlingung des unteren Entwässerungsbandes bezüglich der Abnahmewalze einstellbar ist. Dies erlaubt es beispielsweise zum sicheren Überführen der Faserstoffbahn einen relativ großen Umschlingungswinkel zu bilden.It is also advantageous if the lower dewatering belt wraps around an adjustable guide roller after the transfer of the fibrous web and a gap, a contact or a wrap of the lower dewatering belt with respect to the take-off roller is adjustable via this guide roller. This allows, for example, for safely transferring the fibrous web to form a relatively large wrap angle.

Um Dehnungen der feuchten Faserstoffbahn zur Vermeidung von Faltenbildung ausgleichen zu können, besitzt das übernehmende Band eine höhere Geschwindigkeit als das untere Entwässerungsband.In order to be able to compensate for expansions of the moist fibrous web to avoid wrinkling, the accepting band has a higher speed than the lower dewatering band.

Das Abnahmeband kann als Preßfilz eines folgenden Preßspaltes, als Transferband zum Weitertransport oder als Trockensieb einer folgenden Trockengruppe zur Trocknung der Faserstoffbahn ausgebildet sein. Dabei sollte der Abstand zwischen der Leitwalze des oberen Entwässerungsbandes und dem Abnahmeband einstellbar sein, um somit die in den Zwickel eingeschleppte Luft zu steuern.The removal belt may be formed as a press felt of a following press nip, as a transfer belt for onward transport or as a dryer wire of a following drying group for drying the fibrous web. In this case, the distance between the guide roller of the upper dewatering belt and the take-off belt should be adjustable in order thus to control the entrained air in the gusset.

Für das Erreichen einer intensiven, aber dennoch schonenden Entwässerung der Faserstoffbahn ist es von Vorteil, wenn der Preßspalt der Pressanordnung verlängert ausgeführt ist. Wegen der dabei anfallenden, erheblichen Wassermengen sollten zumindest das untere, vorzugsweise beide Entwässerungsbänder als Preßfilz ausgebildet sein.To achieve an intensive, yet gentle dewatering of the fibrous web, it is advantageous if the press nip of the press assembly is designed to be extended. Because of the resulting considerable amounts of water at least the lower, preferably both dewatering belts should be formed as a press felt.

Besondere Vorteile hinsichtlich einer verbesserten Führung der Faserstoffbahn ergeben sich in Pressanordnungen mit zwei Presspalten, die vorzugsweise beide verlängert ausgebildet sein sollten. Zumindest sollte jedoch der zweite Presspalt verlängert sein. Hierbei kann die erfindungsgemäße Anordnung zwischen den Presspalten und/oder zwischen dem letzten Presspalt und einer folgenden Trockengruppe realisiert sein.Particular advantages with regard to an improved guidance of the fibrous web result in press arrangements with two press nips, which should preferably be both extended. At least, however, the second nip should be extended. Here, the arrangement according to the invention between the press nips and / or between the last press nip and a following Drying be realized.

Besonders geeignet ist die Pressanordnung bei Bahngeschwindigkeiten der Faserstoffbahn von mehr als 1500 m/min.Particularly suitable is the press arrangement at web speeds of the fibrous web of more than 1500 m / min.

Nachfolgend soll die Erfindung an einem Ausführungsbeispiel näher erläutert werden. In der beigefügten Zeichnung zeigt die Figur einen schematischen Querschnitt durch eine erfindungsgemäße Pressanordnung zur Entwässerung einer Faserstoffbahn 1, insbesondere einer Papierbahn.The invention will be explained in more detail with reference to an exemplary embodiment. In the accompanying drawing, the figure shows a schematic cross section through a press arrangement according to the invention for dewatering a fibrous web 1, in particular a paper web.

Durch den, von zwei gegeneinander gedrückten Presswalzen 11, 12 gebildeten Preßspalt ist neben der Faserstoffbahn 1 beidseitig je ein Entwässerungsband 2, 3 in Form eines luftdurchlässigen Preßfilzes zur Aufnahme und zum Abtransport des ausgepressten Wassers geführt. Zur Ermöglichung einer intensiven, aber dennoch schonenden Entwässerung ist der Preßspalt verlängert ausgeführt. Zu diesem Zweck besitzt hier die obere Presswalze 11 einen flexiblen Walzenmantel, der über einen Anpreßschuh mit konkaver Anpressfläche läuft.Due to the press nip formed by two press rolls 11, 12 pressed against one another, a dewatering belt 2, 3 in the form of an air-permeable press felt for receiving and for transporting the squeezed out water is guided on both sides next to the fibrous web 1. To enable an intensive, yet gentle drainage of the press nip is performed extended. For this purpose, here has the upper press roll 11 has a flexible roll shell which runs over a pressure shoe with concave contact surface.

Nach dem Preßspalt wird die Faserstoffbahn 1 in einer gemeinsamen Führungsstrecke 4 von beiden Entwässerungsbändern 2, 3 geführt. Zur Begrenzung der Rückbefeuchtung sollte diese Führungsstrecke 4 möglichst kurz sein.After the press nip, the fibrous web 1 is guided in a common guide path 4 by both dewatering belts 2, 3. To limit the rewet, this guide section 4 should be as short as possible.

Am Ende der Führungsstrecke 4 umschlingt das unterhalb der Faserstoffbahn 1 verlaufende, untere Entwässerungsband 3 gemeinsam mit der Faserstoffbahn 1 eine besaugte Trennwalze 5 mit einem Umschlingungswinkel 8 von ca. 60°. Die vom Unterdruck der Trennwalze 5 ausgehende verstärkte Haftung der Faserstoffbahn 1 erlaubt die Lösung und anschließende Wegführung des oberen Entwässerungsbandes 2 von der Faserstoffbahn 1 in einer Trennstrecke 6. Diese Trennstrecke 6 bildet das Ende der gemeinsamen Führungsstrecke 4, wobei die Verweilzeit der Faserstoffbahn 1 in der Trennstrecke 6 zwischen 1 und 5 ms liegt.At the end of the guide section 4, the lower dewatering belt 3, which extends below the fibrous web 1, wraps around together with the fibrous web 1 an evacuated separating roller 5 with a wrap angle 8 of approximately 60 °. The outgoing from the negative pressure of the separation roller 5 increased adhesion of the fibrous web 1 allows the solution and subsequent removal of the upper drainage belt 2 of the fibrous web 1 in a separation section 6. This separation section 6 forms the end of the common guide section 4, wherein the residence time of the fibrous web 1 in the Isolation distance 6 is between 1 and 5 ms.

Das obere Entwässerungsband 2 wird nach der Trennstrecke 6 zu einer Leitwalze 9 geführt, deren Lage in vertikaler Richtung veränderbar ist, so dass an der Trennwalze 5 eine leichte Umschlingung des oberen Entwässerungsbandes 2 von 0-5 ° eingestellt werden kann. An der Leitwalze 9 erfolgt die Umlenkung und Weiterführung des oberen Entwässerungsbandes 2. Um den Zwickel zwischen Faserstoffbahn 1 und oberen Entwässerungsband 2 möglichst kurz zu gestalten, ist der freie, ungestützte Verlauf des Entwässerungsbandes 2 zwischen Trenn-5 und Leitwalze 9 kleiner als 80 mm. Die Verkürzung des Zwickels begrenzt die, die Führung der Faserstoffbahn 1 beeinträchtigende Luftströmung in den Zwickel.The upper dewatering belt 2 is guided after the separating line 6 to a guide roller 9, the position of which can be changed in the vertical direction, so that a slight looping of the upper dewatering belt 2 of 0-5 ° can be set on the separating roller 5. In order to make the gusset between fibrous web 1 and upper dewatering belt 2 as short as possible, the free, unsupported course of the dewatering belt 2 between separation 5 and guide roller 9 is smaller than 80 mm. The shortening of the gusset limits the, affecting the leadership of the fibrous web 1 affecting air flow in the gusset.

Von der Trennwalze 5 läuft die Faserstoffbahn 1 gemeinsam mit dem unteren Entwässerungsband 3 zu einer, von einem luftdurchlässigen Abnahmeband 7 umschlungenen und besaugten Abnahmewalze 10. Der Unterdruck der Abnahmewalze 10 unterstützt dabei die Übergabe der Faserstoffbahn 1 vom unteren Entwässerungsband 3 an das Abnahmeband 7. Zur Begrenzung des gefährdeten Bereiches, in dem die Faserstoffbahn 1 gemeinsam mit dem unteren Entwässerungsband 3 zwischen Trenn- 5 und Abnahmewalze 10 ohne Bahnstabilisatoren, Saug-oder Blaseinrichtungen verläuft, ist der lichte, das heißt kürzeste Abstand zwischen Trenn-5 und Abnahmewalze 10 kleiner als 80 mm.From the separating roller 5, the fibrous web 1 runs together with the lower dewatering belt 3 to a, from an air-permeable removal belt 7 looped and evacuated pickup roller 10. The negative pressure of the pickup roller 10 supports the transfer of the fibrous web 1 from the lower dewatering belt 3 to the removal belt 7. Zur Limiting the vulnerable area in which the fibrous web 1 runs together with the lower dewatering belt 3 between separation and take-off roll 10 without web stabilizers, suction or blowing devices, the clear, that is the shortest distance between separation 5 and take-off roll 10 is less than 80 mm.

Zum Ausgleich von Dehnungen der feuchten Faserstoffbahn 1 läuft des Abnahmeband 7 etwas schneller als das untere Entwässerungsband 3. Dieser Zug ist so gering, dass keine negativen Auswirkungen auf die Bahnführung zu erwarten sind. Er hängt ab von der Feuchtdehnung der Faserstoffbahn 1, der Maschinengeschwindigkeit und der Längung in der Trockenpartie. Er sollte zwischen zwei Pressen ca. 0,5 - 1,0 % und zwischen der letzten Presse und der Trockenpartie ca. 2,5 - 4,0 % betragen. Außerdem wird das untere Entwässerungsband 3 nach der Übergabe der Faserstoffbahn 1 über eine verstellbare Leitwalze 13 geführt. Durch ihre Verstellung kann eine Umschlingung der Abnahmewalze 10 erreicht werden, was beim Überführen der Faserstoffbahn 1 von Vorteil sein kann. Nach erfolgter Überführung kann dann wieder ein Kontakt oder ein Spalt zwischen dem unteren Entwässerungsband 3 und der Abnahmewalze 10 mit dem Abnahmeband 7 eingestellt werden.To compensate for expansions of the moist fibrous web 1, the removal belt 7 runs slightly faster than the lower dewatering belt 3. This train is so small that no negative effects on the web guide are to be expected. It depends on the moisture elongation of the fibrous web 1, the machine speed and the elongation in the dryer section. It should be approx. 0.5 - 1.0% between two presses and approx. 2.5 - 4.0% between the last press and the dryer section. In addition, the lower dewatering belt 3 is guided over the transfer of the fibrous web 1 via an adjustable guide roller 13. By their adjustment, a wrap of the take-off roll 10 can be achieved, which can be of advantage when transferring the fibrous web 1. After the transfer can then again a contact or a gap between the lower Dewatering belt 3 and the take-off roller 10 are set with the removal belt 7.

Um einer Stauchung des unteren Entwässerungsbandes 3 nach der Trennwalze 5 und damit dem Abheben der Bahnränder der Faserstoffbahn 1 entgegen wirken zu können, sollte neben der Preßwalze 12 und der Trennwalze 5 auch die nach der Abgabe der Faserstoffbahn 1 folgende Leitwalze 13 des unteren Entwässerungsbandes 3 antreibbar sein.In order to counteract a compression of the lower dewatering belt 3 after the separation roller 5 and thus the lifting of the web edges of the fibrous web 1, in addition to the press roll 12 and the separation roller 5 and the following after the delivery of the fibrous web 1 following guide roller 13 of the lower dewatering belt 3 drivable be.

Die höhenverstellbare Leitwalze 9 des oberen Entwässerungsbandes 2 erlaubt es, den Spalt zwischen dieser Leitwalze 9 und dem Abnahmeband 7 und somit die in den Zwickel eingeschleppte Luftmenge zu beeinflussen.The height-adjustable guide roller 9 of the upper dewatering belt 2 makes it possible to influence the gap between this guide roller 9 and the removal belt 7 and thus the entrained air in the gusset.

Das Abnahmeband 7 kann als Preßfilz eines folgenden Preßspaltes oder als Trockensieb einer folgenden Trockengruppe ausgebildet sein.The removal belt 7 may be formed as a press felt of a subsequent press nip or as a dryer wire of a following drying group.

Die besaugten Walzen besitzen einen perforierten Walzenmantel, dessen Innenraum mit einer Unterdruckquelle verbunden ist. Dabei kann der besaugte Bereich der Leitwalzen in seiner Ausdehnung quer zur Faserstoffbahn 1 veränderbar und/oder in separat steuerbaren Unterdruckzonen unterteilt sein. Vorteilhafterweise sollte den Bahnrändern der Faserstoffbahn 1 wegen der erhöhten Gefahr des Abhebens separate Hochvakuumzonen zugeordnet werden.The evacuated rolls have a perforated roll shell, the interior of which is connected to a vacuum source. In this case, the evacuated region of the guide rolls in its extension transversely to the fibrous web 1 can be changed and / or subdivided into separately controllable negative-pressure zones. Advantageously, the web edges of the fibrous web 1 due to the increased risk of lifting should be assigned separate high vacuum zones.

Die Abstände zwischen den Leitwalzen müssen natürlich den Sicherheitsvorschriften genügen.Of course, the distances between the guide rolls must comply with safety regulations.

Claims (15)

  1. Press arrangement having at least one press nip formed by two press rolls (11, 12) for dewatering a paper, board, tissue or other fibrous web (1), through which nip, in addition to the fibrous web (1) a dewatering belt (2, 3) for picking up the water pressed out is in each case guided on both sides, the fibrous web (1) after the press nip being guided by both dewatering belts (2, 3) in a common guide section (4), the lower dewatering belt (3) running underneath the fibrous web (1), together with the fibrous web (1) at the end of the guide section (4), wrapping around an evacuated separating roll (5), the upper dewatering belt (2) arranged above the fibrous web (1) being guided away from the fibrous web (1) in the region of the separating roll (5) in a separating section (6), the fibrous web (1) then being picked up by a pick-up belt (7), which wraps around a pick-up roll (10) the lower watering belt (3) and the fibrous web (1) wrapping around the separating roll (5), adjacent to the separating section (6), with a wrap angle (8) of at least 30°, characterized in that de clearance between the separating roll (5) and the pick-up roll (10) is between 20 and 200 mm, and the pick-up belt (7) has a higher speed than the lower dewatering belt (3).
  2. Press arrangement according to Claim 1, characterized in that the wrap angle (8) is at least 45°, preferably 60°.
  3. Press arrangement according to Claim 1 or 2, characterized in that the residence time of the fibrous web (1) in the separating section (6) is greater than 1 ms, preferably greater than 15 ms.
  4. Press arrangement according to one of the preceding claims, characterized in that, after the separating section (6), the upper dewatering belt (2) is led to a guide roll (9) which deflects the dewatering belt (2), the unsupported course of the dewatering belt (2) between the separating roll (5) and guide roll (9) being between 20 and 200 mm, preferably between 20 and 80 mm, long.
  5. Press arrangement according to Claim 4, characterized in that the position of the guide roll (9) of the upper dewatering belt (2) can be varied and, via the latter, the wrap angle of the upper dewatering belt (2) with respect to the separating rolls (5) can be set between 0 and 5°.
  6. Press arrangement according to one of the preceding claims, characterized in that the fibrous web (1), together with the lower dewatering belt (3), runs from the separating roll (5) to the evacuated pick-up roll (10) which is spaced apart from the latter and wrapped around by the air-permeable pick-up belt (7), where the fibrous web (1) is picked up by the pick-up belt (7).
  7. Press arrangement according to Claim 6, characterized in that the clearance between the separating roll (5) and the pick-up roll (10) is between 20 and 80 mm.
  8. Press arrangement according to Claim 6 or 7, characterized in that, following the transfer of the fibrous web (1), the lower dewatering belt (3) wraps around an adjustable guide roll (13) and, via this guide roll (13), a gap, a contact or a wrap of the lower dewatering belt (3) with respect to the pick-up roll (10) can be set.
  9. Press arrangement according to one of Claims 4 to 8, characterized in that the distance between the guide roll (9) of the upper dewatering belt (5) and the pick-up belt (7) can be adjusted.
  10. Press arrangement according to one of the preceding claims, characterized in that at least the lower dewatering belt, preferably both the dewatering belts (2, 3), are formed as press felts.
  11. Press arrangement according to one of the preceding claims, characterized in that the pick-up belt (7) is formed as a press felt of a following press nip.
  12. Press arrangement according to one of Claims 1 to 10, characterized in that the pick-up belt (7) is formed as a transfer belt.
  13. Press arrangement according to one of Claims 1 to 10, characterized in that the pick-up belt (7) is formed as a dryer fabric of a following drying group for drying the fibrous web (1).
  14. Press arrangement according to one of the preceding claims, characterized in that the press nip of the press arrangement is extended.
  15. Press arrangement according to one of the preceding claims, characterized in that there are two press nips and preferably both, but at least the last press nip, is extended.
EP01101207A 2000-03-13 2001-01-19 Pressing arrangement Expired - Lifetime EP1136619B1 (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
DE10012148 2000-03-13
DE2000112148 DE10012148A1 (en) 2000-03-13 2000-03-13 Paper/cardboard web press section has a dividing point after the roller press gap where the blankets flanking the web are separated to follow structured paths for the web to be picked up for the next station
DE20019256U 2000-11-13
DE20019256U DE20019256U1 (en) 2000-03-13 2000-11-13 Press arrangement

Publications (3)

Publication Number Publication Date
EP1136619A2 EP1136619A2 (en) 2001-09-26
EP1136619A3 EP1136619A3 (en) 2002-08-28
EP1136619B1 true EP1136619B1 (en) 2006-07-05

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Application Number Title Priority Date Filing Date
EP01101207A Expired - Lifetime EP1136619B1 (en) 2000-03-13 2001-01-19 Pressing arrangement

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US (1) US6666954B2 (en)
EP (1) EP1136619B1 (en)
AT (1) ATE332408T1 (en)
DE (1) DE50110372D1 (en)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE50110918D1 (en) * 2000-05-24 2006-10-19 Voith Patent Gmbh drying section
DE10241010A1 (en) * 2002-09-05 2004-03-25 Voith Paper Patent Gmbh transfer tape
FI114647B (en) * 2003-07-02 2004-11-30 Metso Paper Inc An arrangement for controlling the web with a press section of a paper or board machine
DE10333138A1 (en) * 2003-07-22 2005-02-17 Voith Paper Patent Gmbh Press arrangement
DE102016201338A1 (en) * 2016-01-29 2017-08-03 Voith Patent Gmbh Press

Family Cites Families (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FI70950C (en) * 1983-03-25 1986-10-27 Valmet Oy PRESSPARTI MED SLUTET DRAG I PAPPERSMASKIN
DE3425077A1 (en) * 1984-05-25 1985-11-28 Sulzer-Escher Wyss GmbH, 7980 Ravensburg DOUBLE SCREEN PAPER
DE3708191A1 (en) * 1987-03-13 1988-09-22 Voith Gmbh J M WET PRESS
DE4335024C2 (en) * 1993-10-14 1999-09-16 Voith Gmbh J M Press section of a paper machine and transfer device
FI110440B (en) * 1996-04-04 2003-01-31 Metso Paper Inc Transferring the web from the last press nip in the paper machine to the next drying section
DE29701382U1 (en) * 1997-01-28 1997-03-20 Voith Sulzer Papiermaschinen GmbH, 89522 Heidenheim Press section of a paper machine
DE19801417A1 (en) 1998-01-16 1999-07-22 Voith Sulzer Papiertech Patent Papermaking web press section for water extraction
DE19802054A1 (en) 1998-01-21 1999-07-22 Voith Sulzer Papiertech Patent Press section
DE19848284A1 (en) * 1998-04-15 1999-10-28 Voith Sulzer Papiertech Patent Papermaking machine press section
EP0950759A3 (en) 1998-04-15 2000-11-29 Voith Sulzer Papiertechnik Patent GmbH Pressing arrangement
DE29823556U1 (en) 1998-04-15 1999-09-02 Voith Sulzer Papiertech Patent Press arrangement

Also Published As

Publication number Publication date
US20010020524A1 (en) 2001-09-13
EP1136619A3 (en) 2002-08-28
ATE332408T1 (en) 2006-07-15
EP1136619A2 (en) 2001-09-26
DE50110372D1 (en) 2006-08-17
US6666954B2 (en) 2003-12-23

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