EP0716184A2 - Méthode et dispositif pour la déshydratation d'une couche de pâte à papier dans une section de formage à deux toiles - Google Patents

Méthode et dispositif pour la déshydratation d'une couche de pâte à papier dans une section de formage à deux toiles Download PDF

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Publication number
EP0716184A2
EP0716184A2 EP95118093A EP95118093A EP0716184A2 EP 0716184 A2 EP0716184 A2 EP 0716184A2 EP 95118093 A EP95118093 A EP 95118093A EP 95118093 A EP95118093 A EP 95118093A EP 0716184 A2 EP0716184 A2 EP 0716184A2
Authority
EP
European Patent Office
Prior art keywords
guide surface
sieves
screens
screen
forming cylinder
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP95118093A
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German (de)
English (en)
Other versions
EP0716184A3 (fr
Inventor
Thomas Schaible
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Voith Sulzer Papiermaschinen GmbH
Original Assignee
Voith Sulzer Papiermaschinen GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Voith Sulzer Papiermaschinen GmbH filed Critical Voith Sulzer Papiermaschinen GmbH
Publication of EP0716184A2 publication Critical patent/EP0716184A2/fr
Publication of EP0716184A3 publication Critical patent/EP0716184A3/fr
Withdrawn legal-status Critical Current

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Classifications

    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F9/00—Complete machines for making continuous webs of paper
    • D21F9/003—Complete machines for making continuous webs of paper of the twin-wire type

Definitions

  • the invention relates to a method for dewatering a paper fiber layer according to the preamble of claim 1 or 2 and devices for its implementation.
  • Paper fiber webs in the sheet weight range specified in claim 1 are required in the production of comparatively heavy types of paper or cardboard.
  • the necessary rapid dewatering and formation of such layers in gap formers of modern, in particular high-speed, paper machines give rise to very specific problems, as do lighter grades, when driving above 1000 m / min.
  • it is e.g. from US 4,925,531 to use a suction roll and a forming roll in succession, but this known arrangement has an uneven drainage in the particularly important initial area.
  • the dewatering length required on the forming roll is also becoming longer, so that the technical implementation is difficult.
  • the effect of two successively following, rotating, curved guide surfaces, in particular forming cylinders, and a subsequent drainage device are combined.
  • the forming cylinders have a particularly gentle effect on the relatively thick layer of material, alternating in closely opposite drainage directions. Because both guide surfaces are not in the same endless screen, the direction of curvature of the screens changes as they pass through the former. Because of the still high water content of the layer, there is no reason to fear that it could be damaged by redirecting the track.
  • the fibrous layer still has freely moving pulp fibers between the two forming cylinders, since sheet formation has not yet been completed here.
  • the dry content (in percent) at the start of the second guide surface has an order of magnitude which corresponds at least to the numerical value of the sum of the forming cylinder diameter (in meters). Effective, even drainage is achieved on both sides with good formation at the same time. With a short length of the two screens between the two forming cylinders, the suction effect of the preceding forming cylinder can favor the pulling in of the fibrous layer in the area of the second forming cylinder. This also protects the formation.
  • the drainage and forming effect of the guide surfaces is known to be based on the fact that either the surface of the cylinders contains recesses in which the water can be collected until the sieves are removed from the cylinder or that the cylinder surface is permeable and from a negative pressure is applied inside the area of the wire wrap. In the former case, all of the water must be collected in suitable tubs or the like. Forming cylinders and sumps then work so together. In the second case, it can be advantageous to operate the first forming cylinder with and the second without negative pressure. However, other combinations are also conceivable, since the field of application is very broad in the cases considered here.
  • the web weight is given here in mass of the solids content per area. Since the - anhydrous - amount of solids is determined after drying in a suitable oven, this information is sometimes given the addition "otro".
  • a suspension S is injected between two converging endless screens, a transport screen 3 and a counter screen 2.
  • the screens are brought together on a rotating, curved guide surface 5.
  • the guide surface 5 belongs to a screen cylinder which has openings on its cylinder jacket which can receive water, that is to say an open forming cylinder.
  • the two screens and the paper fiber layer located between them are led away from the first guide surface 5 and led to the next guide surface 7, which belongs to a further forming cylinder. This also has openings on its jacket for water absorption.
  • both sieves are removed with the paper fiber layer, they reach a further dewatering device 8. Since this has fixed elements, the sieves move relative to it.
  • the web is then dewatered to such an extent that the formation is then completed.
  • FIG. 2 shows schematically the most important parts of a twin wire former according to the invention.
  • the suspension passes from the headbox 4 between the transport screen 3 and the counter screen 2 and is dewatered on the first forming cylinder 5 '.
  • the two sieves loop around this forming cylinder 5 'at an angle alpha.
  • the water which has been ablated in the area of the first forming cylinder 5 ' reaches a water tank 6 which can be subjected to a vacuum.
  • the twin-wire run is then passed over the forming cylinder 7 ', which it wraps around at an angle beta.
  • the dewatering device 8 in this case with adjustable pressure bars 12 and a suction box 11 located in the opposite screen.
  • the two screens 2 and 3 are separated from one another in the subsequent separating device 13, the paper fiber layer remaining on the transport screen 3.
  • the twin wire former shown in FIG. 3 differs in some points from that of FIG. 2.
  • the headbox 4 is arranged somewhat differently and generates a downward jet.
  • the first forming cylinder lies in the counter screen 2. This arrangement allows a larger wrap angle on the forming cylinder 5 'when the twin wire is deflected into the horizontal.
  • the one behind the Forming cylinder 7 'lying drainage device 8 is constructed somewhat differently. It contains the adjustable pressure bars 10 in the counter-sieve 2 and a suction box 9 in the transport sieve 3. Of course, further arrangements in such drainage devices are familiar to the person skilled in the art.
  • FIG. 4 shows a part of a twin wire former, in which the wrap angle of both forming cylinders 5 'and 7' is greater than that shown in FIG. 3, in a further simplified manner. Furthermore, adjustable pressure bars 16 are present on the second forming cylinder 7 ', which further increase the dewatering effect.
  • FIG. 5 contains, as a further variant, an initial forming cylinder 5 'with a suction device 17, in which the water contained in the fibrous layer can be sucked off through the jacket of the forming cylinder 5'.
  • the openings not only serve to receive the water, but are also suitable for guiding the water into the interior of the forming cylinder.
  • the subsequent forming cylinder 7 ' is without negative pressure.
  • FIG. 6 shows a special aspect of the forming cylinders 5 'and 7' which are relatively close together.

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  • Paper (AREA)
EP95118093A 1994-12-09 1995-11-17 Méthode et dispositif pour la déshydratation d'une couche de pâte à papier dans une section de formage à deux toiles Withdrawn EP0716184A3 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE4443874A DE4443874C2 (de) 1994-12-09 1994-12-09 Doppelsieb-Gap-Former zur Papierherstellung
DE4443874 1994-12-09

Publications (2)

Publication Number Publication Date
EP0716184A2 true EP0716184A2 (fr) 1996-06-12
EP0716184A3 EP0716184A3 (fr) 1997-07-09

Family

ID=6535380

Family Applications (1)

Application Number Title Priority Date Filing Date
EP95118093A Withdrawn EP0716184A3 (fr) 1994-12-09 1995-11-17 Méthode et dispositif pour la déshydratation d'une couche de pâte à papier dans une section de formage à deux toiles

Country Status (5)

Country Link
US (1) US5785816A (fr)
EP (1) EP0716184A3 (fr)
CA (1) CA2164763A1 (fr)
DE (1) DE4443874C2 (fr)
FI (1) FI955908A7 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1998009020A1 (fr) * 1996-08-30 1998-03-05 Voith Sulzer Papiermaschinen Gmbh Section partie humide d'une machine a papier, avec caisse de tete a regulation de densite de la pate et formeur a deux toiles
DE10012342A1 (de) * 2000-03-14 2001-09-20 Voith Paper Patent Gmbh Doppelsiebformer
EP3333314A1 (fr) * 2016-12-08 2018-06-13 Valmet Technologies Oy Unité de formation

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19733318A1 (de) * 1997-08-01 1999-02-04 Voith Sulzer Papiermasch Gmbh Doppelsiebformer
DE10303464A1 (de) * 2003-01-29 2004-09-30 Voith Paper Patent Gmbh Verfahren und Doppelsiebformer einer Maschine zur Herstellung einer Faserstoffbahn
DE10242564A1 (de) * 2002-09-13 2004-03-25 Voith Paper Patent Gmbh Verfahren und Doppelsiebformer einer Maschine zur Herstellung einer Faserstoffbahn
JP5630880B2 (ja) * 2009-07-22 2014-11-26 ビブラント メド−エル ヒアリング テクノロジー ゲーエムベーハー 埋込式デバイスのための磁気取り付け装置

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4925531A (en) 1988-05-23 1990-05-15 Valmet Paper Machinery Inc. Twin wire former for a paper machine

Family Cites Families (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3150037A (en) * 1962-01-04 1964-09-22 Huyck Corp Papermaking machine utilizing centrifugal dewatering
US3951736A (en) * 1974-12-30 1976-04-20 Tadashi Kobayashi Single-layer and multi-layer paper making apparatus
US4414061A (en) * 1975-02-20 1983-11-08 Australian Paper Manufacturers Limited Twin wire paper forming apparatus
FI752585A7 (fr) * 1975-09-16 1977-03-17 Valmet Oy
FI761030A7 (fr) * 1976-04-14 1977-10-15 Valmet Oy
SE410482B (sv) * 1978-02-15 1979-10-15 Karlstad Mekaniska Ab Forfarande och anordning vid en dubbelviraformare
DE3142657C2 (de) * 1981-09-29 1985-06-20 Sulzer-Escher Wyss GmbH, 7980 Ravensburg Entwässerungsvorrichtung
DE3524613A1 (de) * 1985-06-18 1986-12-18 Sulzer-Escher Wyss GmbH, 7980 Ravensburg Apparat zum leiten von siebwasser
SE458212B (sv) * 1987-07-17 1989-03-06 Valmet Paper Machinery Inc Formare foer formning av en pappersbana
FI91788C (fi) * 1990-09-12 1994-08-10 Valmet Paper Machinery Inc Paperikoneen kaksiviirainen rainanmuodostusosa
DE4037017C2 (de) * 1990-11-20 1994-12-08 Escher Wyss Gmbh Naßteil einer Doppelsieb-Papiermaschine
DE4301103C1 (de) * 1993-01-18 1994-08-18 Voith Gmbh J M Siebpartie einer Papiermaschine

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4925531A (en) 1988-05-23 1990-05-15 Valmet Paper Machinery Inc. Twin wire former for a paper machine

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1998009020A1 (fr) * 1996-08-30 1998-03-05 Voith Sulzer Papiermaschinen Gmbh Section partie humide d'une machine a papier, avec caisse de tete a regulation de densite de la pate et formeur a deux toiles
DE10012342A1 (de) * 2000-03-14 2001-09-20 Voith Paper Patent Gmbh Doppelsiebformer
EP3333314A1 (fr) * 2016-12-08 2018-06-13 Valmet Technologies Oy Unité de formation

Also Published As

Publication number Publication date
DE4443874A1 (de) 1996-06-13
CA2164763A1 (fr) 1996-06-10
FI955908L (fi) 1996-06-10
EP0716184A3 (fr) 1997-07-09
FI955908A0 (fi) 1995-12-08
FI955908A7 (fi) 1996-06-10
US5785816A (en) 1998-07-28
DE4443874C2 (de) 1996-10-31

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