EP0894893A2 - Doppelsiebformer - Google Patents
Doppelsiebformer Download PDFInfo
- Publication number
- EP0894893A2 EP0894893A2 EP98111853A EP98111853A EP0894893A2 EP 0894893 A2 EP0894893 A2 EP 0894893A2 EP 98111853 A EP98111853 A EP 98111853A EP 98111853 A EP98111853 A EP 98111853A EP 0894893 A2 EP0894893 A2 EP 0894893A2
- Authority
- EP
- European Patent Office
- Prior art keywords
- wire
- twin
- zone
- suction roll
- former according
- 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- Withdrawn
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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 twin wire former for producing a fibrous web, in particular a high quality graphic paper.
- Starting point of the invention are twin wire formers according to Fig. 6, 8, 12 or 13 of the article Formation and retention in twin-wire formers ", published in the magazine Kliblatt für Textilfabrikation 18, 1990 ", pages 802 to 808.
- Such twin wire former with the commercial name Duoformer F “or Duoformer FM “or Duoformer CF” have proven themselves in numerous applications, particularly in the production of graphic papers, for example newsprint.
- the paper machine in question can be operated at a relatively high working speed, in particular when using a relatively easily dewatered fiber suspension. that paper production was possible in a sufficiently economical manner.
- twin-wire former specified in claim 1 which is preferably designed as a gap former.
- the main idea of the invention is, on the one hand, to combine an increased dewatering capacity in the beginning area of the twin-wire zone with a device known per se (extensively adjustable pressure elements) for introducing pressure pulsations into the fiber suspension (with the aim of achieving the best possible one Formation ", ie fiber distribution as uniform as possible) and on the other hand at the same time also to ensure the highest possible dewatering capacity in the end region of the twin-wire zone, with as little loss of fine and fillers as possible and with as little screen wear as possible.
- two more of Suction rollers wrapped in series and connected in series as far as possible so that stationary drainage elements, eg suction boxes, are only required in a relatively small number or not at all. This reduces the risk of washing out fine and fillers and reduces screen wear.
- Gap "a short underscreen pre-dewatering can also be provided Gap "forming suction roll in the loop of the top wire, because in this way a relatively large amount of water can be easily discharged downwards in the area of the forming suction roll, mostly with the aid of pressure elements, for example strips, which can be adjusted to the bottom wire (preferably flexible).
- the twin-wire former according to the invention allows the twin-wire former according to the invention, to use a fiber suspension with an extremely high degree of grinding and an extremely high filler content, in order to produce high-quality graphic papers Screen wear at.
- the invention also allows existing systems, the one Duoformer F "or FM or CF "have to be converted with relatively little effort in such a way that the system meets the changed requirements. It is particularly favorable to use a system with the known gap former To convert the Duoformer CF "according to the invention, inter alia because the existing headbox suitable for a gap former can be retained; it generally only needs to be positioned differently. All of the aforementioned Duoformern “has in common that they already have two additional suction rolls arranged one behind the other, which in the conversion according to the invention (as second "and third "suction rollers) are maintained and contribute significantly to the fact that the paper machine - despite the difficult drainability of the stock to be processed - can be operated at a relatively high speed.
- the invention differs therefrom, among other things, in that the pressure elements which can be flexibly adjusted to one of the screens are always arranged on a curved wire path, preferably directly on the circumference of the forming suction roll, more rarely on one bulged drainage box downstream of the forming roll. If the pressure elements are on the forming suction roll, there is an essential advantage that their formation-improving effect is already present in the initial area of the twin-wire zone. For many types of paper, this leads to a significant increase in quality, especially with regard to the Formation ".
- FIGS. 1 to 5 schematically shows a twin wire former in side view.
- All of the exemplary embodiments have in common that two endless sieve belts, namely a lower sieve 11 and an upper sieve 12, form a twin-sieve zone with one another.
- the initial area of this twin-wire zone runs approximately horizontally.
- the jet direction of the headbox 10 or 10A is essentially horizontal, mostly it is inclined by approximately 5-20 ° from top to bottom.
- the lower wire 11 runs over a breast roll 13, while the upper wire 12 runs over a forming suction roll 14.
- the two screens 11, 12 form an inlet gusset (or Gap ") for receiving the pulp suspension jet coming from the headbox 10 or 10A.
- Both screens 11 and 12 loop around the forming suction roll 14 to a certain extent. Due to the longitudinal tension of the two screen belts, supported by gravity, a large part flows the suspension liquid downwards through the lower sieve 11. A smaller part reaches the interior of the forming suction roll 14 under the effect of the negative pressure.
- forming suction roll 14 pressure elements e.g. Last 15 provided that are parallel to
- the longitudinal axis of the forming suction roll 14 extends and is flexible, e.g. B. under the effect one pneumatic hose each) can be pressed onto the lower sieve 11.
- the pneumatic hoses are supported on a support structure 15 ', which is preferably pivotable is stored.
- a headbox 10 is provided, which is suitable for a gap former.
- a headbox can also be used 10A are used, the upper lip in a known manner by means of a bending beam 10B is held free of deflection.
- an enlarged horizontal becomes Distance between the breast roll 13 and the forming suction roll 14 is provided. Consequently the bottom wire 11 forms a short single-wire pre-dewatering zone with an additional one Drainage element 13A.
- the two screens 11 and 12 (together with the fiber web forming in between) in the end region of the twin-wire zone via a second suction roller 18 and a third suction roller 19.
- the path of the sieves over this Rolling is meandering, so that there are relatively large wrap angles. This ensures a high drainage capacity.
- a deflector 20 may be provided between the two suction rolls. Otherwise you avoid in this area stationary drainage elements to wash out fine and fillers to be avoided as far as possible and to reduce screen wear.
- a preferred embodiment is that according to FIG. 5.
- additional stationary Drainage elements omitted.
- Only one collecting device 25 for Splashing water can e.g. B. can be provided on the circumference of the forming suction roll 14.
- the horizontal one Distance between the rollers 14 and 18 is compared to the other embodiments drastically reduced, so that this twin wire former has the additional Advantage of an extremely short overall length.
- Drainage box 29 may be provided, which can be pressed against the upper sieve 12 with flexibility
- Deflectors 28 works together. These are at a water catchment facility 28 'arranged, the effect of which can be increased by means of negative pressure. 4 shows an additional stationary drainage device behind the drainage box 29 17, which can also be omitted.
- the suction rolls 18 and 19 already mentioned are usually arranged one above the other, the lower suction roller 18 in the loop of the upper wire 12 and the upper suction roller 19 lies in the loop of the lower sieve 11. Separate the two sieve belts 11 and 12 on the circumference of the upper suction roller 19. The lower wire 11 runs over several rollers 21 back to the breast roll 13, the top wire 12 back over several rolls 22 Forming suction roll 14. The fibrous web follows the lower wire 11 and is known in the Way by means of a felt belt 23 and a take-off suction roller 24 of the following Press section (not shown) fed.
Landscapes
- Paper (AREA)
Abstract
Description
Claims (9)
- Doppelsiebformer zum Herstellen einer Faserstoffbahn, insbesondere eines hochwertigen graphischen Papiers, aus einer Faserstoffsuspension, gekennzeichnet durch die Kombination der folgenden, einzeln schon bekannten Merkmale:a) zwei endlose Siebbänder, nämlich ein Untersieb (11) und ein Obersieb (12) bilden miteinander eine Doppelsiebzone, die in ihrem Anfangsbereich im wesentlichen horizontal verläuft oder zur Horizontalen höchstens um 20° geneigt ist;b) im Anfangsbereich der Doppelsiebzone laufen die Siebbänder über eine in der Schlaufe des Obersiebes liegende Formiersaugwalze (erste Saugwalze 14);c) in der Doppelsiebzone sind mehrere entlang einer gekrümmten Sieblaufstrecke angeordnete und nachgiebig gegen eines der Siebe anstellbare Druckelemente (z.B. Leisten 15) vorgesehen, zwecks Einleitung von Druckpulsationen in die zwischen den Sieben vorhandene Faserstoffsuspension;d) im Endbereich der Doppelsiebzone laufen die Siebe gemeinsam über eine zweite, in der Schlaufe des Obersiebes (12) liegende Saugwalze (18, 19), danach über eine dritte, in der Schlaufe des Untersiebes liegende Saugwalze (19), an der sich das Obersieb von der Faserstoffbahn trennt;
- Doppelsiebformer nach Anspruch 1, dadurch gekennzeichnet, daß die Druckelemente (15) im Bereich des Umfanges der Formiersaugwalze (14) an das Untersieb (11) anstellbar sind (Fig. 1, 2, 4 oder 5).
- Doppelsiebformer nach Anspruch 1, dadurch gekennzeichnet, daß Druckelemente (28)
- Doppelsiebformer nach einem der Ansprüche 1 bis 4, dadurch gekennzeichnet, daß im Anfangsbereich der Doppelsiebzone ein keilförmiger Einlaufzwickel derart angeordnet ist, daß er die Faserstoffsuspension in Form eines freien Strahles aufnimmt (Gapformer) (Fig. 1, 3 bis 5).
- Doppelsiebformer nach einem der A 1 bis 4, dadurch gekennzeichnet, daß der Doppelsiebzone eine kurze, durch das Untersieb (11) gebildete Ein-Sieb-Vorentwässerungszone vorgeschaltet ist (Fig. 2).
- Doppelsiebformer nach einem der Ansprüche 1 bis 6 dadurch gekennzeichnet, daß in der Doppelsiebzone zusätzliche stationäre Entwässerungselemente (16, 17) vorgesehen sind.
- Doppelsiebformer nach einem der Ansprüche 1 bis 6, dadurch gekennzeichnet, daß der Bereich zwischen Formiersaugwalze (14) und zweiter Saugwalze (18) zumindest weitgehend frei von zusätzlichen Entwässerungselementen ist (Fig. 5).
- Doppelsiebformer nach Anspruch 8, dadurch gekennzeichnet, daß zwischen der Formiersaugwalze (14) und der zweiten Saugwalze (18) nur ein kleiner Abstand besteht.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19733318 | 1997-08-01 | ||
DE1997133318 DE19733318A1 (de) | 1997-08-01 | 1997-08-01 | Doppelsiebformer |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0894893A2 true EP0894893A2 (de) | 1999-02-03 |
EP0894893A3 EP0894893A3 (de) | 1999-07-14 |
Family
ID=7837705
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP98111853A Withdrawn EP0894893A3 (de) | 1997-08-01 | 1998-06-26 | Doppelsiebformer |
Country Status (4)
Country | Link |
---|---|
EP (1) | EP0894893A3 (de) |
BR (1) | BR9802788A (de) |
CA (1) | CA2244542A1 (de) |
DE (1) | DE19733318A1 (de) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1096067A3 (de) * | 1999-10-21 | 2001-09-05 | Voith Paper Patent GmbH | Former |
EP1075568B1 (de) * | 1999-01-28 | 2006-05-03 | Voith Paper Patent GmbH | Maschine und verfahren zur herstellung einer mehrlagigen faserstoffbahn |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0438681A1 (de) * | 1990-01-26 | 1991-07-31 | Voith Sulzer Papiermaschinen GmbH | Entwässerungsvorrichtung an einem Doppelsiebformer |
EP0627523A1 (de) * | 1993-05-18 | 1994-12-07 | Valmet Paper Machinery Inc. | Doppelsiebformer in einer Papiermaschine |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE4002305C2 (de) * | 1990-01-26 | 1996-02-22 | Voith Sulzer Papiermasch Gmbh | Entwässerungsvorrichtung an einem Doppelsiebformer |
DE9201722U1 (de) * | 1992-02-12 | 1992-04-23 | J.M. Voith Gmbh, 7920 Heidenheim | Doppelsiebpartie für eine Papiermaschine |
DE4301103C1 (de) * | 1993-01-18 | 1994-08-18 | Voith Gmbh J M | Siebpartie einer Papiermaschine |
DE4328024A1 (de) * | 1993-08-20 | 1995-02-23 | Voith Gmbh J M | Doppelsieb-Blattbildner |
DE4443874C2 (de) * | 1994-12-09 | 1996-10-31 | Voith Sulzer Papiermasch Gmbh | Doppelsieb-Gap-Former zur Papierherstellung |
-
1997
- 1997-08-01 DE DE1997133318 patent/DE19733318A1/de not_active Withdrawn
-
1998
- 1998-06-26 EP EP98111853A patent/EP0894893A3/de not_active Withdrawn
- 1998-07-30 BR BR9802788A patent/BR9802788A/pt not_active IP Right Cessation
- 1998-07-30 CA CA 2244542 patent/CA2244542A1/en not_active Abandoned
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0438681A1 (de) * | 1990-01-26 | 1991-07-31 | Voith Sulzer Papiermaschinen GmbH | Entwässerungsvorrichtung an einem Doppelsiebformer |
EP0627523A1 (de) * | 1993-05-18 | 1994-12-07 | Valmet Paper Machinery Inc. | Doppelsiebformer in einer Papiermaschine |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1075568B1 (de) * | 1999-01-28 | 2006-05-03 | Voith Paper Patent GmbH | Maschine und verfahren zur herstellung einer mehrlagigen faserstoffbahn |
EP1096067A3 (de) * | 1999-10-21 | 2001-09-05 | Voith Paper Patent GmbH | Former |
Also Published As
Publication number | Publication date |
---|---|
BR9802788A (pt) | 1999-11-03 |
EP0894893A3 (de) | 1999-07-14 |
DE19733318A1 (de) | 1999-02-04 |
CA2244542A1 (en) | 1999-02-01 |
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