EP0304561B1 - Dewatering press with steam supply - Google Patents

Dewatering press with steam supply Download PDF

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Publication number
EP0304561B1
EP0304561B1 EP88108738A EP88108738A EP0304561B1 EP 0304561 B1 EP0304561 B1 EP 0304561B1 EP 88108738 A EP88108738 A EP 88108738A EP 88108738 A EP88108738 A EP 88108738A EP 0304561 B1 EP0304561 B1 EP 0304561B1
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EP
European Patent Office
Prior art keywords
paper web
pressing
dewatering
press
shoe
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.)
Expired - Lifetime
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EP88108738A
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German (de)
French (fr)
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EP0304561A1 (en
Inventor
Hans Dr. Dipl.-Ing. Dahl
Herbert Dipl.-Ing. Holik
Reinhard Dipl.-Ing. Bluhm
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Sulzer Escher Wyss GmbH
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Sulzer Escher Wyss GmbH
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Priority to AT88108738T priority Critical patent/ATE69840T1/en
Publication of EP0304561A1 publication Critical patent/EP0304561A1/en
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    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F3/00—Press section of machines for making continuous webs of paper
    • D21F3/02—Wet presses
    • D21F3/0209—Wet presses with extended press nip
    • D21F3/0218—Shoe presses
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F3/00—Press section of machines for making continuous webs of paper
    • D21F3/02—Wet presses
    • D21F3/0272—Wet presses in combination with suction or blowing devices
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
    • B65H2801/00—Application field
    • B65H2801/84—Paper-making machines

Definitions

  • the invention relates to a dewatering press specified in the preamble of claim 1.
  • the invention is intended to achieve better, higher drying results without damaging the paper web.
  • the process should be clear and manageable.
  • the process taking place in the press nip is fully controllable, since the supply of the water vapor selected to flow through the paper web can be regulated as required.
  • a high heat flow density can be achieved in the paper web.
  • This flow medium does not cause cooling, e.g. with air, inside the paper web to be dried, since the condensation heat released is available for further heating of the paper web.
  • the resulting high temperature in the paper web to be dried supports the drying effect by reducing the viscosity and the surface tension in the displacement of capillary water from the web.
  • the removal of the water vapor with the expelled liquid is also clear and manageable.
  • the dewatering press of a paper machine is provided for dewatering the paper web 1 with a stream of a gaseous medium passed through the paper web.
  • the dewatering takes place in a press nip 2 between an upper press surface 3 and a lower press surface 4, where the paper web is compressed to such an extent that at least part of the paper web is in a saturated state.
  • Saturated is the state in which all voids in the paper web are filled with water.
  • This adjustable water vapor flow which transports the liquid from the web, is brought about by means used in the area of the press nip 2.
  • Fig. 1 shows the arrangement of such a dewatering press.
  • the water vapor flow is brought about by the following means used in the area of the press nip 2: the upper roller 3 has a perforated jacket 5, and an externally generated water vapor under pressure is pressed through it by means of a pressure chamber (not shown) through the perforated jacket 5 the press nip 2 to the upper surface of the paper web 1 is regulated.
  • the wide nip press shoe 13 is integrated in an upper roll 33 as a wide nip roll with a support 12 and press shoe 13 around which a perforated, flexible jacket 52 is arranged.
  • the press shoe 13 is pressed against the lower roller 4 with a pressure medium 14, the water vapor via line 15 into the press nip 2 through the pressure chamber 13 1 present in the press shoe and opened to the jacket 5 2 or to the press nip 2 and through the perforated flexible jacket 52 is performed.
  • a vapor cushion is created here that statically Paper web, or a felt tape and the paper web supports and prevents friction on the shoe surface or edges.
  • the lower roller 4 also has a perforated jacket 6 and the water vapor stream flowing through the web 1 is sucked in through the perforated jacket 6 with the liquid which has thus been expelled from the paper web.
  • the suction power via a suction chamber can also be regulated.
  • the entire drying process is clear and easy to control. It is also conceivable to provide the lower roller jacket 6 with an externally grooved surface on which the water vapor flowing through the web 1 can be removed with the liquid expelled from it.
  • the roller pair described with the rollers 3 and 4 can be preceded by a few roller pairs 7 for pre-pressing or pre-dewatering with a gradually increasing pressing pressure, possibly with a higher temperature in each case.
  • felt tapes 8 and 9 are provided between the surface of the paper web 1 and the relevant roller 3 and 4, respectively , both of which have good vapor permeability.
  • One felt band 8 could be omitted if such a marking were tolerable or even desired.
  • Both embodiments just described can be varied by pressing the press shoe against the press nip 2 with steam pressure and guiding the water vapor from the press shoe's pressure chamber in the manner known for hydrostatic pressing elements through the press shoe into its pressure pocket 13 1.
  • a press shoe operated with steam could be designed in this way (FIG. 3).
  • the upper roller 3 has a perforated jacket 5 through which the water vapor is guided to the press nip 2.
  • the counter roll 4 forming the press nip 2 is a wide nip roll of the type described above with an impermeable flexible jacket 5 1.
  • a felt belt 9 1 is provided, which has a large receiving volume and is able to absorb the water vapor flow after flowing through the paper web 1 and partially to divert it in the running direction.
  • the felt belt 9 1 In addition to being able to "suck in” the steam, the felt belt 9 1 not only has good transport properties and the high absorption capacity, it can also be cooled in order to also dewater the web due to the temperature gradient between the hot and the cool side of the paper web support by condensing some of the water vapor in the cooled felt.
  • the pressure pocket 13 1 of the press shoe is fed with a cooling medium via a line 16. It would also be possible to pre-cool the felt belt with suitable means before entering the press nip 2. It would also be conceivable to design the lower roller as a cooled full-surface roller and thus and / or with said pre-cooling 11 to cool the suction felt belt (see FIGS. 3 and 11).
  • FIG. 12 also shows an imaginable embodiment of the press nip shoe, in which it has pressure chambers (13 1) which are provided with a porous or perforated cover (13 3) in the pressing direction.
  • a perforated upper roller 3 for guiding the steam and a lower cooling roller 4 are shown.
  • the steam can be transported through the felt 9 1 in the running direction.
  • the steam is introduced into a wide press nip from a wide press shoe through a permeable elastic jacket 51.
  • a cooled felt belt 9 2 is provided on a cooling roller 4 on the discharge side.
  • Fig. 9 one can see an upper perforated roller 3 for introducing the steam into the wide press nip which is formed with a wide press nip shoe 13 2 which is provided on the discharge side.
  • the paper web is guided through the wide press nip between an upper and a lower felt 8 or 9.
  • the paper web 1 is passed between the two felts 8 and 9 through a wide press nip which is formed between a convex surface of the upper shoe 13 1 and the concave surface of the lower shoe 13 2.
  • the two press shoes can be pressed against each other, as indicated by arrows.
  • the surfaces are perforated and the paper web 1 is guided between the felts 8 and 9.
  • Fig. 7 shows a drainage in the flat wide press nip which is formed between flat pressing surfaces of the upper shoe 13 1 and the lower shoe 13 2.
  • the upper one is a heating shoe, the lower one is for removal. Preheating must also be ensured here. as is provided, for example, in the construction with apparatus 10 according to FIG. 2.
  • Equipment acc. Figure 8 also has a flat, wide press nip.
  • the steam is fed onto the paper web from the upper shoe 13 1 through a permeable flexible belt 5 1.
  • a press shoe 13 2 is provided on the discharge side and is opened to a felt belt 9 supporting the paper web.
  • the paper web 1 is guided between two felts 8 and 9 through a flat wide press nip which is formed between the press shoes 13 1 and 13 2.
  • the pressing surfaces 26 of the shoes are located on both sides of the openings in the press shoes, which are provided for guiding the steam through the paper web 1.
  • the wide press shoes are each operated by a force-generating element 231 or 232 in the pressing direction.
  • FIG. 4 shows an opposite construction to FIG. 9.
  • a perforated suction roller 4 is arranged on the discharge side.
  • On the feed side there is provided a wide-nip shoe 13 which forms a wide-nip with the roller 4. Due to the steam pressure in the press shoe 13, the felt 8 moves gently and with little friction on a steam cushion.

Abstract

The dewatering of the paper web (1) takes place by means of a flow of steam led through the paper web (1) in a press nip (2) between two pressing surfaces (3 and 4) under such pressure that at least part of the paper web (1) becomes saturated. In order to effect this flow of steam, means are introduced in the area of the press nip (2) to guide the flow of steam from the upper to the under surface of the paper web (1) running through the press nip (2) with simultaneous removal from the undersurface of the paper web. In one embodiment, the means are an upper roll (3) with a perforated jacket (5), through which the externally produced steam is led under pressure into the press nip (2), and a lower roll (4) with a perforated jacket (6), through which the steam, together with the liquid expressed from the paper web, is sucked out and removed. <IMAGE>

Description

Die Erfindung betrifft eine Entwässerungspresse der im Oberbegriff des Anspruchs 1 angegebenen Art.The invention relates to a dewatering press specified in the preamble of claim 1.

Es ist bekannt, daß die Entwässerung einer Papierbahn erhöht werden kann, wenn neben der mechanischen Pressung noch Wärme eingesetzt wird. Dazu sind z.B. beheizte Trocknungswalzen bekannt, an die die Bahn angepreßt wird, oft mit einem Filzband, das die von der heißen Walzenoberfläche verdrängte Feuchte aufnehmen soll. Das Band wird oft mit einigen Anpreßwalzen an die Trocknungswalze gepreßt. Hier bewegt sich der an der Walze entstehende Wasserdampf in Richtung von der Walzenoberfläche weg und reißt das in der Bahn vorhandene Wasser mit. Wenn dies bei einem komprimierten Zustand der Papierbahn geschieht, spricht man von sogenanntem "impulse drying". Dabei werden die in diesem Zeitpunkt vollgefüllten Kapillaren zumindest teilweise entleert. Bei Anwendung von hohen Heiztemperaturen kann hinter dem Preßnip der sogenannte "flash effect" auftreten, wo das Wasser durch den sich blitzschnell entwickelnden Wasserdampf aus der Bahn getrieben wird.It is known that the dewatering of a paper web can be increased if heat is used in addition to mechanical pressing. For this, e.g. heated drying rollers known, to which the web is pressed, often with a felt belt that is supposed to absorb the moisture displaced by the hot roller surface. The belt is often pressed onto the drying roller with some pressure rollers. Here, the water vapor generated on the roller moves away from the roller surface and entrains the water present in the web. If this happens in a compressed state of the paper web, one speaks of so-called "impulse drying". The capillaries fully filled at this point are at least partially emptied. When using high heating temperatures, the so-called "flash effect" can occur behind the press nip, where the water is driven out of the web by the water vapor, which develops at lightning speed.

Obzwar dies alles bekannt ist, sind erfolgreiche, großtechnische Realisationen problematisch oder maschinenbaulich aufwendig. Meistens ist der Trocknungsprozeß unkontrollierbar, was einerseits zu Beschädigungen der Papierbahn durch das Trocknen führt, oder es sind die erzielten Trocknungsgehaite unbefriedigend.Although all of this is known, successful, large-scale implementations are problematic or require mechanical engineering. The drying process is usually uncontrollable, which on the one hand leads to damage to the paper web due to drying, or the drying contents achieved are unsatisfactory.

In einer älteren amerikanischen Patentschrift, der US 2,696,148, werden zwar auch zwei perforierte Flächen mit dazwischen liegender Papierbahn und Filz zusammengepresst, wobei gleichzeitig das Durchströmen eines Fluids von einer Walze in die andere ermöglicht ist, dennoch ist bei dieser Ausführung wegen des nur kurzen Preßvorgangs der Entwässerungseffekt unbefriedigend. Auch wurden die Vorteile, die sich besonders mit Wasserdampf ergeben, nicht erkannt. Eine andere Heißgaspresse, etwa gemäß US 3,162,568, arbeitet mit heißer Luft oder Dampf und bringt ihre Entwässerungswirkung nur in einen kurzen Zeitpunkt auf. Eine solche Presse ist auch schwer kontrollierbar wegen des allseits austretenden Dampfes.In an older American patent, US 2,696,148, two perforated surfaces with a paper web and felt in between are also pressed together, at the same time allowing a fluid to flow from one roller into the other, but in this embodiment, because of the short pressing process, the Drainage effect unsatisfactory. The advantages that particularly arise with water vapor were also not recognized. Another hot gas press, for example according to US Pat. No. 3,162,568, works with hot air or steam and only exerts its dewatering effect in a short time. Such a press is too difficult to control due to the steam escaping from all sides.

Die an sich bekannte Breitspaltpresse, z.B. gemäß EP 0 151 447 A3, kann in dieser Form nur zum einphasigen Naßpressen benutzt werden, da die Preßschuhe mit Öl gefüllt und gegen den Preßspalt abgeschlossen sind.The wide-gap press known per se, e.g. According to EP 0 151 447 A3, this form can only be used for single-phase wet pressing, since the press shoes are filled with oil and sealed against the press nip.

Durch die Erfindung sollen bessere, höhere Trocknungsergebnisse ohne Beschädigung der Papierbahn erzielt werden. Der Prozeß soll übersichtlich und beherrschbar werden.The invention is intended to achieve better, higher drying results without damaging the paper web. The process should be clear and manageable.

Diese Aufgabe ist erfindungsgemäß an einer Entwässerungspresse der eingangs beschriebenen Art durch die im Kennzeichen des Anspruchs 1 angegebenen Maßnahmen voll erfüllt.This object is fully achieved according to the invention on a dewatering press of the type described in the introduction by the measures specified in the characterizing part of claim 1.

Der im Preßnip stattfindende Prozeß ist voll beherrschbar, da die Zuführung des zum Durchströmen der Papierbahn auserwählten Wasserdampfes einfach nach Bedarf regulierbar ist. Bei der Kondensation des Dampfes ist eine hohe Wärmestromdichte in der Papierbahn erreichbar. Dieses Durchströmmedium verursacht nämlich keine Kühlung, wie z.B. mit Luft, innerhalb der zu trocknenden Papierbahn, da die frei werdende Kondensationswärme zur weiteren Aufheizung der Papierbahn zur Verfügungsteht. Die daraus resultierende hohe Temperatur in der zu trocknenden Papierbahn unterstützt den Trocknungseffekt durch Herabsetzung der Viskosität und der Oberflächenspannung bei der Verdrängung von Kapillarwasser aus der Bahn. Bei der erfindungsgemäßen Entwässerungspresse ist auch das Abführen des Wasserdampfes mit der herausgetriebenen Flüssigkeit übersichtlich und beherrschbar.The process taking place in the press nip is fully controllable, since the supply of the water vapor selected to flow through the paper web can be regulated as required. When the steam is condensed, a high heat flow density can be achieved in the paper web. This flow medium does not cause cooling, e.g. with air, inside the paper web to be dried, since the condensation heat released is available for further heating of the paper web. The resulting high temperature in the paper web to be dried supports the drying effect by reducing the viscosity and the surface tension in the displacement of capillary water from the web. In the dewatering press according to the invention, the removal of the water vapor with the expelled liquid is also clear and manageable.

In den Unteransprüchen sind sinnvolle Ausführungsbeispiele der erfindungsgemäßen Entwässerungspresse angegeben.In the dependent claims, useful embodiments of the dewatering press according to the invention are given.

Im weiteren wird der Erfindungsgegenstand näher beschrieben und erklärt. Die Beschreibung bezieht sich auf Zeichnungen, in welchen zeigen:

  • Figur 1 bis 12 jeweils eine erfindungsgemäße Entwässerungspresse in schematischer Darstellung.
The subject matter of the invention is described and explained in more detail below. The description refers to drawings in which:
  • Figure 1 to 12 each a drainage press according to the invention in a schematic Presentation.

Die Entwässerungspresse einer Papiermaschine ist für die Entwässerung der Papierbahn 1 bei einem durch die Papierbahn geführten Strom eines gasförmigen Mediums vorgesehen.The dewatering press of a paper machine is provided for dewatering the paper web 1 with a stream of a gaseous medium passed through the paper web.

Die Entwässerung findet in einem Preßspalt 2 zwischen einer oberen Preßfläche 3 und einer unteren Preßfläche 4 statt, wo die Papierbahn so weit komprimiert ist, daß mindestens ein Teil der Papierbahn in gesättigtem Zustand ist. Als gesättigt bezeichnet man den Zustand , bei dem alle Hohlräume in der Papierbahn mit Wasser gefüllt sind. Bei der Entwässerung wird durch die durch den Preßspalt 2 laufende Papierbahn 1 ein regulierbarer Wasserdampfstrom von der oberen zu der unteren Oberfläche der Papierbahn 1 geführt und an der unteren Oberfläche der Papierbahn aus der Papierbahn abgeführt.The dewatering takes place in a press nip 2 between an upper press surface 3 and a lower press surface 4, where the paper web is compressed to such an extent that at least part of the paper web is in a saturated state. Saturated is the state in which all voids in the paper web are filled with water. During dewatering, a controllable water vapor flow is guided through the paper web 1 running through the press nip 2 from the upper to the lower surface of the paper web 1 and discharged from the paper web on the lower surface of the paper web.

Dieser regulierbare Wasserdampfstrom, der die Flüssigkeit aus der Bahn transportiert, wird mit im Bereich des Preßspaltes 2 eingesetzten Mitteln bewirkt.This adjustable water vapor flow, which transports the liquid from the web, is brought about by means used in the area of the press nip 2.

Fig. 1 zeigt die Anordnung solch einer Entwässerungspresse. Dabei wird der Wasserdampfstrom durch folgende im Bereich des Preßspaltes 2 eingesetzte Mittel bewirkt: Die obere Walze 3 weist einen perforierten Mantel 5 auf, und über sie wird mit Hilfe einer Druckkammer (nicht gezeichnet) durch den perforierten Mantel 5 ein extern erzeugter Wasserdampf unter Druck in den Preßspalt 2 zu der oberen Oberfläche der Papierbahn 1 reguliert zugeführt.Fig. 1 shows the arrangement of such a dewatering press. The water vapor flow is brought about by the following means used in the area of the press nip 2: the upper roller 3 has a perforated jacket 5, and an externally generated water vapor under pressure is pressed through it by means of a pressure chamber (not shown) through the perforated jacket 5 the press nip 2 to the upper surface of the paper web 1 is regulated.

Bei dem Ausführungsbeispiel gemäß Fig. 2 ist der Breitpreßspalt-Preßschuh 13 in eine obere Walze 3³ als Breitnipwalze integriert mit einem Träger 12 und Preßschuh 13, um welche ein perforierter, flexibler Mantel 5² angeordnet ist. Der Preßschuh 13 wird gegen die untere Walze 4 mit einem Druckmittel 14 gepreßt, wobei der Wasserdampf über Leitung 15 in den Preßspalt 2 durch die in dem Preßschuh vorhandene, zum Mantel 5², bzw. zum Preßspalt 2 geöffnete Druckkammer 13¹ und durch den perforierten flexiblen Mantel 5² geführt wird. Hier entsteht ein Dampfpolster, das statisch die Papierbahn, bzw. ein Filzband und die Papierbahn stützt und Reibung an der Schuhoberfläche oder Kanten verhindert. Das Absaugen des Wasserdampfstromes nach der Durchströmung der Papierbahn 1 geschieht über die untere Walze 4 mit einem perforierten Mantel 6 auf die schon vorher beschriebene Weise. Auch hier ist zwischen der Papierbahn und der unteren Walze 4 ein Filzband 9 - wie auch ein Filzband am Mantel 5² - vorgesehen.In the embodiment shown in FIG. 2, the wide nip press shoe 13 is integrated in an upper roll 3³ as a wide nip roll with a support 12 and press shoe 13 around which a perforated, flexible jacket 5² is arranged. The press shoe 13 is pressed against the lower roller 4 with a pressure medium 14, the water vapor via line 15 into the press nip 2 through the pressure chamber 13 1 present in the press shoe and opened to the jacket 5 2 or to the press nip 2 and through the perforated flexible jacket 5² is performed. A vapor cushion is created here that statically Paper web, or a felt tape and the paper web supports and prevents friction on the shoe surface or edges. The suction of the water vapor stream after flowing through the paper web 1 takes place via the lower roller 4 with a perforated jacket 6 in the manner already described. Here too, a felt belt 9 - as well as a felt belt on the jacket 5² - is provided between the paper web and the lower roller 4.

Die untere Walze 4 weist ebenso einen perforierten Mantel 6 auf und über sie wird durch den perforierten Mantel 6 der durch die Bahn 1 strömende Wasserdampfstrom mit der aus der Papierbahn damit noch herausgetriebenen Flüssigkeit angesaugt. Auch die Saugleistung über eine Saugkammer (nicht gezeichnet) kann reguliert erfolgen. So ist der ganze Trocknungsvorgang übersichtlich und leicht kontrollierbar. Es ist auch denkbar, den unteren Walzenmantel 6 mit außen gerillter Oberfläche zu versehen, an der der durch die Bahn 1 strömende Wasserdampf mit der aus ihr herausgetriebenen Flüssigkeit abgeführt werden kann. So wie in Fig. 1 gezeigt, können dem beschriebenen Walzenpaar mit den Walzen 3 und 4 noch einige Walzenpaare 7 zur Vorpressung bzw. Vorentwässerung mit stufenweise steigendem Preßdruck, ggfs. mit stufenweise jeweils höherer Temperatur vorgeschaltet werden. Um eine Markierung der Papierbahn 1 im Preßspalt 2 durch die Perforierung der Walzen 3 und 4, bzw. ihrer Mäntel 5 und 6 zu vermeiden, sind jeweils zwischen der Oberfläche der Papierbahn 1 und der bezüglichen Walze 3 bzw. 4 Filzbänder 8 bzw. 9 vorgesehen, die beide gute Dampfdurchlässigkeiten besitzen. Das eine Filzband 8 könnte entfallen, wenn so eine Markierung tolerierbar oder sogar gewünscht wäre.The lower roller 4 also has a perforated jacket 6 and the water vapor stream flowing through the web 1 is sucked in through the perforated jacket 6 with the liquid which has thus been expelled from the paper web. The suction power via a suction chamber (not shown) can also be regulated. The entire drying process is clear and easy to control. It is also conceivable to provide the lower roller jacket 6 with an externally grooved surface on which the water vapor flowing through the web 1 can be removed with the liquid expelled from it. As shown in FIG. 1, the roller pair described with the rollers 3 and 4 can be preceded by a few roller pairs 7 for pre-pressing or pre-dewatering with a gradually increasing pressing pressure, possibly with a higher temperature in each case. In order to avoid marking the paper web 1 in the press nip 2 through the perforation of the rollers 3 and 4, or their jackets 5 and 6, felt tapes 8 and 9 are provided between the surface of the paper web 1 and the relevant roller 3 and 4, respectively , both of which have good vapor permeability. One felt band 8 could be omitted if such a marking were tolerable or even desired.

Es wäre vorstellbar, einen z.B. heißen Luftstrom auf die beschriebene Weise zur Trocknung der Papierbahn durch diese zu treiben. Dies brächte jedoch nur Nachteile gegenüber dem beschriebenen Einsatz von Wasserdampf. Mit Wasserdampf als Treibmittel wird die Bahn nicht gekühlt, sondern durch Kondensieren sogar zusätzlich erwärmt und damitdie Viskosität erniedrigt. Außerdem ist damit die Bahn beim Eintritt in die Trockenpartie bereits stark aufgewärmt, was allein dadurch wesentliche Dampfersparnis in der Trockenpartie ergibt.It would be conceivable to drive a hot air stream through the paper web in the manner described for drying it. However, this would only have disadvantages compared to the use of steam described. With steam as the blowing agent, the web is not cooled, but is even additionally heated by condensation, thus lowering the viscosity. In addition, the web is already warmed up strongly when entering the dryer section, which alone results in substantial steam savings in the dryer section.

Beide eben beschriebenen Ausführungsformen lassen sich variieren, indem der Preßschuh mit Dampfdruck gegen den Preßspalt 2 gedrückt und der Wasserdampf aus dem Druckraum des Preßschuhs auf die bei hydrostatischen Anpresselementen bekannte Weise durch den Preßschuh in dessen Drucktasche 13¹ geführt wird. Nach dem bekannten hydrostatischen Vorbild könnte so ein mit Dampf betriebener Preßschuh ausgeführt werden (Fig. 3).Both embodiments just described can be varied by pressing the press shoe against the press nip 2 with steam pressure and guiding the water vapor from the press shoe's pressure chamber in the manner known for hydrostatic pressing elements through the press shoe into its pressure pocket 13 1. According to the known hydrostatic model, a press shoe operated with steam could be designed in this way (FIG. 3).

In dem Ausführungsbeispiel mit Dampfpolstern gemäß Fig. 10 hat die obere Walze 3 einen perforierten Mantel 5, durch welchen der Wasserdampf zum Preßspalt 2 geführt wird. Die den Preßspalt 2 mitbildende Gegenwalze 4 ist eine Breitnipwalze der oben beschriebenen Art mit einem undurchlässigen flexiblen Mantel 5¹. Zwischen der Walze 4 und der Papierbahn 1 ist ein Filzband 9¹ vorgesehen, welches ein großes Aufnahmevolumen hat und den Wasserdampfstrom nach Durchströmung der Papierbahn 1 aufzunehmen und teilweise in Laufrichtung abzuleiten vermag. Um darüberhinaus ein "Ansaugen" des Dampfes ermöglichen zu können, hat das Filzband 9¹ nicht nur gute Transporteigenschaften und die hohe Aufnahmekapazität, es kann auch gekühlt werden, um auch durch den Temperaturgradient zwischen der heißen und der kühlen Seite der Papierbahn die Entwässerung der Bahn zu unterstützen, indem ein Teil des Wasserdampfes im gekühlten Filz kondensiert wird . Dazu wird die Drucktasche 13¹ des Preßschuhs mit einem Kühlungsmedium über eine Leitung 16 gespeist. Es wäre auch zusätzlich möglich, das Filzband vor dem Eintritt in den Preßspalt 2 mit geeigneten Mitteln vorzukühlen. Es wäre auch vorstellbar, die untere Walze als gekühlte Vollmantelwalze auszuführen und damit und/oder mit der besagten Vorkühlung 11 das Saugfilzband zu kühlen (siehe Fig. 3 und 11).10, the upper roller 3 has a perforated jacket 5 through which the water vapor is guided to the press nip 2. The counter roll 4 forming the press nip 2 is a wide nip roll of the type described above with an impermeable flexible jacket 5 1. Between the roller 4 and the paper web 1, a felt belt 9 1 is provided, which has a large receiving volume and is able to absorb the water vapor flow after flowing through the paper web 1 and partially to divert it in the running direction. In addition to being able to "suck in" the steam, the felt belt 9 1 not only has good transport properties and the high absorption capacity, it can also be cooled in order to also dewater the web due to the temperature gradient between the hot and the cool side of the paper web support by condensing some of the water vapor in the cooled felt. For this purpose, the pressure pocket 13 1 of the press shoe is fed with a cooling medium via a line 16. It would also be possible to pre-cool the felt belt with suitable means before entering the press nip 2. It would also be conceivable to design the lower roller as a cooled full-surface roller and thus and / or with said pre-cooling 11 to cool the suction felt belt (see FIGS. 3 and 11).

Es ist in Fig. 12 auch eine vorstellbare Ausführung des Breipreßspalt-Schuhs gezeigt,bei welchem dieser Druckkammern (13¹) aufweist, die in Preßrichtung mit einer porösen oder perforierten Abdeckung (13³) versehen sind.FIG. 12 also shows an imaginable embodiment of the press nip shoe, in which it has pressure chambers (13 1) which are provided with a porous or perforated cover (13 3) in the pressing direction.

Der Erfindungsgegenstand ist keinesfalls nur auf die beschriebenen Ausführungsbeispiele, wie sie in den Figuren schematisch gezeigt sind, beschränkt. Hauptsächlich sind die Begriffe "oben" und "unten" nur zur Vereinfachung der Beschreibung verwendet worden. Es sind auch beliebig anders im Raum angeordnete Ausführungen vorstellbar. Z.B. könnte die Papierbahn vertikal im Raum verlaufen, wobei Achsen der die den Preßspalt bildenden Walzen in einer horizontalen Ebene liegen würden.The subject matter of the invention is in no way limited to the exemplary embodiments described, as shown schematically in the figures. Mainly, the terms "top" and "bottom" are only for the sake of simplification Description has been used. Versions arranged differently in the room are also conceivable. For example, the paper web could run vertically in space, with the axes of the rolls forming the press nip lying in a horizontal plane.

In der erwähnten Fig. 11 ist eine perforierte obere Walze 3 zum Führen des Dampfes und eine untere Kühlwalze 4 gezeigt. Es entsteht ein Temperatur- und damit ein Druck-Gradient, der bewirkt, daß die Flüssigkeit in den gekühlten unteren Filz 9¹ von großem Saugvermögen und Volumen verdrängt wird. Ferner kann der Dampf durch den Filz 9¹ in Laufrichtung transportiert werden.11, a perforated upper roller 3 for guiding the steam and a lower cooling roller 4 are shown. A temperature and thus a pressure gradient arises which causes the liquid in the cooled lower felt 9 1 to be displaced by great suction capacity and volume. Furthermore, the steam can be transported through the felt 9 1 in the running direction.

Gemäß Fig. 3 wird der Dampf in einen Breitpreßspalt aus einem Breitpreßschuh über einen durchlässigen elastischen Mantel 5¹ eingeleitet. An der Abführseite ist ein gekühltes Filzband 9² an einer Kühlwalze 4 vorgesehen.3, the steam is introduced into a wide press nip from a wide press shoe through a permeable elastic jacket 51. A cooled felt belt 9 2 is provided on a cooling roller 4 on the discharge side.

In Fig. 9 sieht man eine obere perforierte Walze 3 zum Einführen des Dampfes in den Breitpreßspalt, der mit einem Breitpreßspaltschuh 13²gebildet ist, welcher an der Abführseite vorgesehen ist. Die Papierbahn wird durch den Breitpreßspalt zwischen einem oberen und einem unteren Filz 8 bzw. 9 geführt.In Fig. 9 one can see an upper perforated roller 3 for introducing the steam into the wide press nip which is formed with a wide press nip shoe 13 2 which is provided on the discharge side. The paper web is guided through the wide press nip between an upper and a lower felt 8 or 9.

In Fig. 5 ist die Papierbahn 1 zwischen den zwei Filzen 8 und 9 durch einen Breitpreßspalt geführt, der zwischen einer konvexen Fläche des oberen Schuhs 13¹ und der konkaven Fläche des unteren Schuhs 13² gebildet wird. Die beiden Preßschuhe sind zueinander preßbar, wie mit Pfeilen angedeutet ist. Die Flächen sind perforiert, und die Papierbahn 1 ist zwischen den Filzen 8 und 9 geführt.In Fig. 5, the paper web 1 is passed between the two felts 8 and 9 through a wide press nip which is formed between a convex surface of the upper shoe 13 1 and the concave surface of the lower shoe 13 2. The two press shoes can be pressed against each other, as indicated by arrows. The surfaces are perforated and the paper web 1 is guided between the felts 8 and 9.

Fig. 7 zeigt eine Entwässerung im flachen Breitpreßspalt, der zwischen ebenen Preßflächen des oberen Schuhes 13¹ und des unteren Schuhes 13² gebildet ist. Der obere ist ein Heizschuh, der untere dient der Abführung. Auch hier muß für das Vorheizen gesorgt werden. wie es z.B. bei der Konstruktion mit Apparat 10 gemäß Fig. 2 vorgesehen ist.Fig. 7 shows a drainage in the flat wide press nip which is formed between flat pressing surfaces of the upper shoe 13 1 and the lower shoe 13 2. The upper one is a heating shoe, the lower one is for removal. Preheating must also be ensured here. as is provided, for example, in the construction with apparatus 10 according to FIG. 2.

Apparatur gem. Figur 8 weist auch einen ebenen Breitpreßspalt auf. Der Dampf wird auf die Papierbahn aus dem oberen Schuh 13 ¹ durch ein durchlässiges flexibles Band 5¹ geführt. An der Abführseite ist ein Preßschuh 13² vorgesehen, der zu einem die Papierbahn stützenden Filzband 9 geöffnet ist.Equipment acc. Figure 8 also has a flat, wide press nip. The steam is fed onto the paper web from the upper shoe 13 1 through a permeable flexible belt 5 1. A press shoe 13 2 is provided on the discharge side and is opened to a felt belt 9 supporting the paper web.

Im Beispiel gemäß Fig. 6 ist die Papierbahn 1 zwischen zwei Filzen 8 und 9 durch einen ebenen Breitpreßspalt geführt, der zwischen den Preßschuhen 13¹ und 13² gebildet ist. Die Preßflächen 26 der Schuhe befinden sich beiderseits der Öffnungen in den Preßschuhen, die zum Führen des Dampfes durch die Papierbahn 1 vorgesehen sind. Die Breitpreßschuhe werden jeweils von einem krafterzeugenden Element 23¹ bzw. 23² in Preßrichtung betätigt.In the example according to FIG. 6, the paper web 1 is guided between two felts 8 and 9 through a flat wide press nip which is formed between the press shoes 13 1 and 13 2. The pressing surfaces 26 of the shoes are located on both sides of the openings in the press shoes, which are provided for guiding the steam through the paper web 1. The wide press shoes are each operated by a force-generating element 23¹ or 23² in the pressing direction.

Fig. 4 zeigt eine umgekehrte Konstruktion zu Fig. 9. An der Abführseite ist eine perforierte Saugwalze 4 angeordnet. An der Zuführseite ist ein mit der Walze 4 einen Breitpreßspalt bildender Breitpreßspaltschuh 13 vorgesehen. Durch den Dampfdruck im Preßschuh 13 bewegt sich der Filz 8 schonend und reibungsarm auf einem Dampfkissen.FIG. 4 shows an opposite construction to FIG. 9. A perforated suction roller 4 is arranged on the discharge side. On the feed side there is provided a wide-nip shoe 13 which forms a wide-nip with the roller 4. Due to the steam pressure in the press shoe 13, the felt 8 moves gently and with little friction on a steam cushion.

Claims (15)

  1. A dewatering press for a paper-making machine with means for the regulable impelling of a gaseous medium through the paper web which is to be dewatered, with the point of dewatering being the press nip (2) between the two pressing surfaces (3, 4 or 13¹, 13⁴) which exert the dewatering pressure on the paper web, with at least one pressing surface being perforated and a felt belt being provided between a pressing surface and the paper web (1) and at least part of the paper web (1) in the press nip (2) being in the saturated state, characterised in that the gaseous medium is water vapour, that one pressing surface has a wide press nip pressing shoe (13), with the water vapour being impelled into the press nip (2) via a pressure chamber (13¹) of the pressing shoe (13) and through the perforated shell (5²), and the removal of the liquid displaced from the paper web with the vapour taking place by means of a felt belt (9) (Fig. 2).
  2. A dewatering press according to Claim 1, characterised in that the water vapour is guided under pressure via a pressure chamber (14) beneath the wide press nip pressing shoe (13) and passes therefrom through the pressing shoe into its pressure chamber (13¹) (Fig. 2).
  3. A dewatering press according to Claim 1, characterised in that an upper pressing surface is constructed as a roller (3³) with a perforated shell (5²).
  4. A dewatering press according to Claim 3, characterised in that a felt belt (8) is provided between the shell (5²) and the paper web (1) (Fig. 2).
  5. A dewatering press according to Claim 1, characterised in that a wide pressing shoe (13) having a concave pressure chamber is provided, via the pressure chamber of which the water vapour is impelled into the press nip (2), with a felt belt (8) being guided between the pressing shoe (13) and the paper web (Fig. 4).
  6. A dewatering press according to Claim 1, characterised in that a wide pressing shoe (13) having a convex pressure chamber (13¹) is provided, via which shoe the water vapour is impelled into the pressing point (2), with a felt belt (8) being guided between the paper web (1) and the pressing shoe (Fig. 5).
  7. A dewatering press according to Claim 1, characterised in that a flat wide pressing shoe (13) is provided, via the pressure chamber (24) of which the water vapour is impelled to the pressing point (2) (Fig. 6, 7, 8).
  8. A dewatering press according to Claim 7, characterised in that the pressure chamber (24) has a narrow opening to the pressing point (2), with the surfaces close to the opening serving as guide and pressing surfaces for a felt (9) which is guided between the pressing shoe and the paper web (1) (Fig. 6).
  9. A dewatering press according to Claim 7, characterised in that the wide press nip pressing shoe has several pressure chambers, with water vapour being impelled through each chamber at adjustable pressures and temperatures (Fig. 8).
  10. A dewatering press according to Claim 1, characterised in that for removing the liquid displaced from the paper web (2) with the vapour, a felt belt (91) is guided through the press nip (2), the suction volume of which belt is sufficiently large to absorb the liquid displaced from the paper web (2) and to transport it away in the direction of travel, and which felt belt is cooled during operation (Fig. 3).
  11. A dewatering press according to Claim 10, characterised in that the felt is cooled on a lower wide press nip roller (4) (Fig. 10), the wide press nip press shoe (13) of which is acted upon by a cooling medium.
  12. A dewatering press according to Claim 10, characterised in that a cooling device (11) is provided for cooling the felt belt (9¹) which is intended to remove the liquid which is displaced from the paper web (2) with the vapour.
  13. A dewatering press according to Claim 1, characterised in that a preliminary pressing part precedes the press nip (2) for preliminary dewatering of the paper web before the press nip (2).
  14. A dewatering press according to Claim 1, characterised in that a heating device (10) is provided for preheating the paper web before the press nip (2).
  15. A dewatering press according to Claim 1, 3, 5, 6, 7, 8 or 9, characterised in that the wide press nip pressing shoe (13) has pressure chambers (13¹) which are provided in the direction of pressing with a porous or perforated cover (13³) (Fig. 12).
EP88108738A 1987-08-22 1988-06-01 Dewatering press with steam supply Expired - Lifetime EP0304561B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT88108738T ATE69840T1 (en) 1987-08-22 1988-06-01 DRAINAGE PRESS WITH STEAM FEED.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3728124 1987-08-22
DE19873728124 DE3728124A1 (en) 1987-08-22 1987-08-22 DRAINAGE PRESS WITH STEAM FEED

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EP0304561A1 EP0304561A1 (en) 1989-03-01
EP0304561B1 true EP0304561B1 (en) 1991-11-27

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AT (1) ATE69840T1 (en)
DE (2) DE3728124A1 (en)

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ATE69840T1 (en) 1991-12-15
EP0304561A1 (en) 1989-03-01
DE3728124A1 (en) 1989-03-02
DE3866469D1 (en) 1992-01-09
DE3728124C2 (en) 1991-06-27

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