WO1998046823A1 - Procede et dispositif servant a reguler un debit dans la caisse d'arrivee d'une machine a papier - Google Patents

Procede et dispositif servant a reguler un debit dans la caisse d'arrivee d'une machine a papier Download PDF

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Publication number
WO1998046823A1
WO1998046823A1 PCT/FI1998/000295 FI9800295W WO9846823A1 WO 1998046823 A1 WO1998046823 A1 WO 1998046823A1 FI 9800295 W FI9800295 W FI 9800295W WO 9846823 A1 WO9846823 A1 WO 9846823A1
Authority
WO
WIPO (PCT)
Prior art keywords
pipes
turbulence
head box
fibre suspension
distributor
Prior art date
Application number
PCT/FI1998/000295
Other languages
English (en)
Inventor
Antti Vaahto
Erkki Aho
Original Assignee
Vaahto Oy
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 Vaahto Oy filed Critical Vaahto Oy
Priority to AU67335/98A priority Critical patent/AU6733598A/en
Publication of WO1998046823A1 publication Critical patent/WO1998046823A1/fr

Links

Classifications

    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F1/00—Wet end of machines for making continuous webs of paper
    • D21F1/02—Head boxes of Fourdrinier machines
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F1/00—Wet end of machines for making continuous webs of paper
    • D21F1/02—Head boxes of Fourdrinier machines
    • D21F1/026—Details of the turbulence section
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F1/00—Wet end of machines for making continuous webs of paper
    • D21F1/06—Regulating pulp flow
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F1/00—Wet end of machines for making continuous webs of paper
    • D21F1/08—Regulating consistency

Definitions

  • Control flow system (method and device) in the headbox of
  • the objective of the invention is a control flow system in a paper machine head box for the control of the fibre suspension flow discharging therefrom.
  • the formation of a continuous web on a paper machine contains the following steps: - the fibres coming from the pulp mill or pulp mill storage tank are led as a mushy pulp to the paper machine, to its feed pump ;
  • the required paper additives or fillers can in this connection be dosed to the pulp; - in the feed pump the pulp is mixed into the process white water coming from the paper machine so that a suspension with a solids content of e.g. 0,3 - 0,8% is obtained;
  • the fibre-water suspension thus obtained is fed, generally through a pipe with a big diameter, to the head box and via its slice to the paper machine wire.
  • the task of the of head box is to spread the fibres and other suspension components on the paper machine wire at a speed approximately corresponding to the speed of the paper machine, and in a right thickness as an uniform jet extending over the whole width of the wire, so that the desired grammage (g/m 2 ) is obtained for the web formed.
  • the most important properties especially for printing paper are the uniformity of its grammage over the whole width of the web and also in the longitudinal direction, as well as the so called formation, which means the uniform distribution of the paper fibres.
  • a bad formation appears as "cloudiness" when inspecting the paper sheet against the light.
  • One of the objectives if the subject invention is to provide a head box in which the- control mechanism of the slice can be avoided.
  • Another objective of the invention is to provide a head box in which the fibres of the suspension flowing to the wire are evenly dispersed and do not form such fibre deposits which cause bad formation of the paper.
  • the main objective of the subject invention is to provide in the head box such a fibre suspension flow system which guarantees the control of an even suspension thickness over the whole width of the head box at the stage when the fibre suspension discharges through the slice to the paper machine wire.
  • the Fl-application 156/65 already presents, at least partly, a method for controlling the eveness of the paper so that several separate dilution water flows are led to the head box close to its discharge opening over the whole machine width in order to even local thickness variations in the suspension.
  • This method cannot, however, eliminate the varying cross-flows in the head box itself, which make the slice flow instable and difficult to control .
  • the newest technique contains, therefore, solutions in which the suspension flow coming to the head box is divided into longitudinal zones by partitions or alike over the whole width of the head box.
  • the principle of the reference invention is applied in each one of these, however so that the control flow is mixed into the actual basic suspension corresponding to the fi- bre web to be formed long before the slice area.
  • the task of the distributing chamber which is missing from the reference publication, is to uniform and calm the flow coming from the separate distributor pipes before the turbulence generator, i.e. the turbulence part.
  • the head of the turbulence generator comprises in relation to the flow direction almost similar pipes as the distributor pipes, but these expand in their ends into e.g. squares so that they fill the flow area corresponding to the whole slice chamber.
  • the objective of the turbulence generator is to disperse the fibre suspension as efficiently as possible in order to provide a good formation for the paper manufactured.
  • the circulation water is led through several, tightly adjacent feed pipes to the distributing chamber close to the turbulence tubing.
  • the amount of circulation water i.e. "dilution fluid" according to the arrangement can be adjusted in a desired way over the whole width of the machine.
  • the control flows are brought as close as possible to the head box slice chamber, there is the risk that the actual fibre suspension flow coming from the distributing chamber to the turbulence generator is disturbed to that extent that the ef- feet aimed at is not achieved in respect of the thickness nor the quantitative control of the flow.
  • the fibre suspension flow in the distributing chamber can be partly uncontrolled, when it is difficult to affect even with additional flow tubes.
  • the method according to the application FI-94 6181 requires that the "additional liquid flow", which means the circulation water from the paper machine diluting the main pulp flow, is brought to be led to the head box already before the distribu- tor pipes of the manifold-system.
  • the dilution water flow at that stage is directed at a certain area of the head box width, nothing guarantees that the so achieved change in the suspension thickness would effect the fibre distribution of the suspension jet discharging from the head box.
  • the manifold there are no partitions or alike to prevent possible cross-flows .
  • the objective of the invention is to provide in the paper machine head box such an apparatus and method for the local con- trol of the fibre suspension thickness in cross direction that the disadvantages observed in the head boxes of the reference publications can be avoided.
  • the apparatus according to the invention is mainly characterized in that all fibre suspension distributor pipes of the head box manifold-system extend as such, without thereto related water units, straight through the head box intermediate chamber close to the turbulence generator, and the thickness of the fibre suspension flowing in the distributor pipes is the one determined in the head box feed pump system, and that the water required for the control dilution of the fibre suspension is obtained from the head box intermediate chamber.
  • the method according to the invention is characterized in that the control dilution water is mixed with the fibre suspension flowing via the head box inside the head box before its slice chamber, and that all fibre suspension distributor pipes of the head box manifold-system extend as such, without thereto related water units, straight through the head box intermediate chamber close to the turbulence generator, and that at least part of the distributor pipes are double-cased to enable the external casing to slide there in relation to the internal cas- ing in order to adjust the length of the distributor pipes in relation to the turbulence pipe.
  • Fig. 1 presents schematically the head of the paper machine wire portion including the head box and the related fibre suspension and process water flow arrangements
  • Fig. 2 shows a schematic profile section of the fibre sus- pension manifold and the turbulence generator with its turbulence pipes according the invention
  • Fig. 3 shows a top view of the head box manifold and the turbulence generator according to the invention
  • Figs. 4a, 4b and 4 c show different alternative locations of the fibre suspension distributor pipes in relation to their axially corresponding turbulence pipes .
  • Fig. 5 shows one construction of a double-cased distributor pipe head in relation to its corresponding turbulence generator turbulence tube used in one embodiment of the invention.
  • Fig. 1 illustrates the embodiment of the operating principle of the paper machine head box and wire portion presented in the beginning of the specification of the invention.
  • the paper fi- bres come e.g. from the pulp mills storage tank (not shown) as a mushy pulp via the M-pipe 12 to the paper machine head box feeding pump 13 , which is connected with the pipe 14 to the circulation water basin 15 of the paper machine wire portion.
  • the feeding pump 13 sucks circulation water from the basin 15 and simultaneously also pulp M coming via the pipe 12 with the valves 16 in a adjustable ratio so that e.g. a 0,3 - 0,5 % suspension F is obtained, and feeds it to the head box 1 and from there further to the paper machine wire in an as such known way.
  • Another pump 17 is connected to the circulation water basin 15, which pump 17 feeds dilution water W to the system 18 providing the thickness control in the head box 1.
  • the head box can either be fully hydraulic or provided with an air-bag.
  • Fig. 2 shows a partial profile drawing of the head box part to which the fibre suspension initially is led through the manifold-system main pipe 5.
  • the reference number 6 refers to the distributor pipes branching from the main pipe, which distributor pipes are several parallel and on top of each other at even distances over the whole width of the head box.
  • the suspension flows through the straight distributor pipes 6 close to the head box turbulence chamber and further to the turbulence pipes 8, which are coaxial with distributor pipes and of equal amount as the distributor pipes.
  • the intermediate chamber 4 is an es- sential part of the apparatus, to which chamber 4 the pump 17 shown in fig. 1 continuously feeds circulation water required for the dilution of the fibre suspension through the pipe 18, which extends transversely over the head box width and has several branches provided with the valves 19. The amount of branch pipes depends on the width of the head box.
  • the in- termediate chamber 4 is provided with partitions 10. These partitions divide the intermediate chamber into compartments, which are equally many as the branches exiting from the dilution water pipe 18. With the valves 19 shown in fig. 2, the amount and pressure of the dilution water can be controlled in each compartment of the intermediate chamber.
  • Figs. 4a, 4b and 4c show principal alternative solutions for the internal installation of the distributor pipes 6 and the turbulence pipes 8. It is essential for the arrangement of the subject invention that the diameter of the distributor pipes 6 is smaller than the diameter of the corresponding turbulence pipes 8. This enables the dilution water surrounding the distributor pipes to mix with the fibre suspension F coming from the distributor pipe in a desired way, which fibre suspension thereafter proceeds thickness controlled in the corresponding turbulence pipes to the head box slice chamber and further to the wire. Factors that effect the so embodied control of the suspension thickness are i.a. the diameter ratio between the turbulence pipes and distributor pipes, as well as very essentially the distance of the distributor pipe head from the corresponding turbulence pipe opening. This distance can even be "negative", i.e. the distributor pipe head can to some extent be pushed into the turbulence pipe, as shown in fig. 4a.
  • Fig. 5 shows one possible embodiment of the invention using a distributor pipe of special construction provided with a double-casing 11a, lib.
  • the external casing 11a is accommodated sliding in relation to the internal casing lib, whereby a suit- able mechanism can be connected to the external casing enabling thus the adjustment of the distributor pipe length.
  • This arrangement does not require the distributor pipe to be double- cased throughout its whole length.
  • Different forms of embodiment of the invention have been presented in the specification above. The invention is, however, not to be considered as so restricted, but the different fea- tures of the invention can be modified within the scope of the invention.

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  • Paper (AREA)

Abstract

L'invention concerne un système de régulation de débit dans la caisse d'arrivée d'une machine à papier permettant de garantir la régularité de l'épaisseur de la suspension de fibres sur la totalité de la largeur de la caisse d'arrivée au stade de décharge de la suspension de fibres à travers la chambre de séparation vers la table plate de la machine à papier. Ce procédé est caractérisé par le fait que l'eau de dilution est mélangée avec l'écoulement de suspension de fibres à travers la caisse d'arrivée à l'intérieur de cette dernière avant sa chambre de séparation et que la totalité des conduits de fibres de la caisse d'arrivée appartenant au système collecteur s'étend sur un trajet rectiligne à travers la chambre intermédiaire de la caisse d'arrivée à proximité du générateur de turbulences et qu'au moins une partie des conduits de distribution présente une double paroi afin de régler la longueur de ces conduits de distribution par rapport au conduit de turbulence.
PCT/FI1998/000295 1997-04-14 1998-04-02 Procede et dispositif servant a reguler un debit dans la caisse d'arrivee d'une machine a papier WO1998046823A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU67335/98A AU6733598A (en) 1997-04-14 1998-04-02 Control flow system (method and device) in the headbox of a paper machine

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FI971561 1997-04-14
FI971561A FI101726B1 (fi) 1997-04-14 1997-04-14 Säätövirtausjärjestelmä (menetelmä ja -laite) paperikoneen perälaatikossa

Publications (1)

Publication Number Publication Date
WO1998046823A1 true WO1998046823A1 (fr) 1998-10-22

Family

ID=8548610

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/FI1998/000295 WO1998046823A1 (fr) 1997-04-14 1998-04-02 Procede et dispositif servant a reguler un debit dans la caisse d'arrivee d'une machine a papier

Country Status (3)

Country Link
AU (1) AU6733598A (fr)
FI (1) FI101726B1 (fr)
WO (1) WO1998046823A1 (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1073178C (zh) * 1999-04-07 2001-10-17 中国计量科学研究院 纸浆浓度测控仪
WO2005024127A1 (fr) * 2003-09-09 2005-03-17 Metso Paper, Inc. Appareil connecte a la caisse d'arrivee d'une machine a papier ou analogue
EP1793035A2 (fr) * 2005-11-30 2007-06-06 Voith Patent GmbH Caisse de tête d'une machine de fabrication d'une bande fibreuse
EP2589702A1 (fr) * 2011-11-02 2013-05-08 Metso Paper Inc. Caisse de tête pour une machine pour fabriquer une bande de matière fibreuse
CN103669076A (zh) * 2013-12-23 2014-03-26 云南中烟昆船瑞升科技有限公司 高效浆水混合装置

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4213707A1 (de) * 1992-04-25 1993-10-28 Escher Wyss Gmbh Stoffauflaufeinrichtung für eine Papiermaschine
EP0683266A1 (fr) * 1994-05-13 1995-11-22 Voith Sulzer Papiermaschinen GmbH Caisse de tête pour une machine à papier avec addition locale de fluide
EP0745722A2 (fr) * 1995-06-01 1996-12-04 Valmet Corporation Caisse de tête pour une machine à papier ou carton

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4213707A1 (de) * 1992-04-25 1993-10-28 Escher Wyss Gmbh Stoffauflaufeinrichtung für eine Papiermaschine
EP0683266A1 (fr) * 1994-05-13 1995-11-22 Voith Sulzer Papiermaschinen GmbH Caisse de tête pour une machine à papier avec addition locale de fluide
EP0745722A2 (fr) * 1995-06-01 1996-12-04 Valmet Corporation Caisse de tête pour une machine à papier ou carton

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1073178C (zh) * 1999-04-07 2001-10-17 中国计量科学研究院 纸浆浓度测控仪
WO2005024127A1 (fr) * 2003-09-09 2005-03-17 Metso Paper, Inc. Appareil connecte a la caisse d'arrivee d'une machine a papier ou analogue
US7485206B2 (en) 2003-09-09 2009-02-03 Metso Paper, Inc. Apparatus in connection with a headbox of a paper machine or equivalent
EP1793035A2 (fr) * 2005-11-30 2007-06-06 Voith Patent GmbH Caisse de tête d'une machine de fabrication d'une bande fibreuse
EP1793035A3 (fr) * 2005-11-30 2011-06-29 Voith Patent GmbH Caisse de tête d'une machine de fabrication d'une bande fibreuse
EP2589702A1 (fr) * 2011-11-02 2013-05-08 Metso Paper Inc. Caisse de tête pour une machine pour fabriquer une bande de matière fibreuse
CN103669076A (zh) * 2013-12-23 2014-03-26 云南中烟昆船瑞升科技有限公司 高效浆水混合装置

Also Published As

Publication number Publication date
FI101726B (fi) 1998-08-14
FI101726B1 (fi) 1998-08-14
FI971561A0 (fi) 1997-04-14
AU6733598A (en) 1998-11-11

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