WO2000077298A1 - Procede permettant d'eliminer l'eau de la partie toile d'un sechoir de pulpe et d'un unite d'essorage - Google Patents

Procede permettant d'eliminer l'eau de la partie toile d'un sechoir de pulpe et d'un unite d'essorage Download PDF

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Publication number
WO2000077298A1
WO2000077298A1 PCT/FI2000/000518 FI0000518W WO0077298A1 WO 2000077298 A1 WO2000077298 A1 WO 2000077298A1 FI 0000518 W FI0000518 W FI 0000518W WO 0077298 A1 WO0077298 A1 WO 0077298A1
Authority
WO
WIPO (PCT)
Prior art keywords
dewatering
wire
rising wall
water
pulp
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.)
Ceased
Application number
PCT/FI2000/000518
Other languages
English (en)
Inventor
Leo LUNDÉN
Jorma Koskinen
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.)
Valmet Technologies Oy
Original Assignee
Metso Paper Oy
Valmet 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 Metso Paper Oy, Valmet Oy filed Critical Metso Paper Oy
Priority to AU50809/00A priority Critical patent/AU5080900A/en
Publication of WO2000077298A1 publication Critical patent/WO2000077298A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
    • D21C9/18—De-watering; Elimination of cooking or pulp-treating liquors from the pulp
    • 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
    • D21F1/48—Suction apparatus

Definitions

  • the present invention relates to a method for removing water from a pulp web travelling between the top and bottom wires on the wire section of a pulp dryer, in which method is used at least one non-vacuum dewatering unit arranged inside the top wire, the said dewatering unit comprising a dewatering strip, the tip part of which can be brought into contact with the surface of the top wire facing away from the web in order to guide the water on the said surface upwards along the rising wall of the dewatering strip, and further into a collection space belonging to the dewatering unit.
  • the invention also relates to a non-vacuum dewatering unit for removing water from a pulp web travelling between the top and bottom wires on the wire section of a pulp dryer, the said dewatering unit being arranged inside the top wire and comprising a dewatering strip, the tip part of which can be brought into contact with the surface of the top wire facing away from the web in order to guide the water on the said surface upwards along the rising wall of the dewatering strip, and further into a collection space belonging to the dewatering unit.
  • the invention further relates to a method for drying chemical pulp in the wire section of a pulp dryer, the wire section comprising a bottom wire onto which is supplied pulp from the headbox, and a top wire, whereby the web being formed is made to travel between the bottom and top wires, this wire unit comprising first dewatering means in conjunction with the bottom wire, the said means being located in the area between the headbox and the top wire, and second dewatering means arranged inside the top wire.
  • the main purpose of the dryer used for drying the pulp is to render the chemical pulp as dry as desired, as cost-effectively as possible, and it should be remembered that the material being dried is chemical pulp and not a mixture of different fibrous materials and additives, as is the case in paper manufacture. This entails, among other things, that the mechanical removal of water from the pulp should be as efficient as possible without, however, damaging the pulp fibres themselves.
  • pulp drying and paper manufacture relates to essentially different grammages which are in the case of chemical pulp of the order of 600-1000 g/m 2 , whereas for board, the maximum grammage is about 550 g/m 2 and for paper the maximum is about 150 g/m 2 .
  • the speed of known pulp dryers is typically less than 200 m/min, whereas in a paper machine, the speeds may be of the order of over 1600 m/min.
  • paper/board is always an end product, the demands placed on which are completely different from those placed on dried pulp, which is a raw material.
  • the demands made on dried pulp relate mainly to its handling during drying, to the requirements made by the handling of the dried pulp, transport, and pulping at the paper mill.
  • the aim is not to significantly affect the properties of the pulp sheet itself by means of the pulp dryer.
  • the process is defined by the qualities required of the end product, such as smoothness, gloss, opacity, printing quality, etc.
  • a particular aim of the invention is to provide a novel improved dewatering method and dewatering unit, by means of which the removal of water above the web is rendered more efficient and more economical.
  • it is characteristic of the method relating to the invention that, in the method, the water made to rise upwards along the rising wall by means of the tip part of the dewatering strip is led off the rising wall in such a way that the upwards directed movement of the water takes place substantially as a free jet.
  • the dewatering unit relating to the invention is, on the other hand, characterised in that in the rising wall of the dewatering strip are arranged means for effecting the detachment of the water from the rising wall in such a way that the upwards directed movement of the water takes place substantially as a free jet.
  • Yet another aim of the invention is to provide an improved method for drying chemical pulp in the wire section of the pulp dryer, the said method being characterised in that, in the method, the dry matter content of the chemical pulp is increased by means of the bottom wire and the first dewatering means to a value below approximately 10%, after which the web is guided into the space between the top wire and the bottom wire and its dry matter content is increased to a value of approximately 18-20% by means of two-way dewatering by utilising the said second dewatering means.
  • FIG. 1 shows diagrammatically an arrangement for a pulp dryer implemented in accordance with the invention
  • Figure 2 shows a part of an embodiment of a dewatering unit relating to the invention
  • Figure 2a shows an enlarged view of a detail of Figure 2
  • Figure 3 shows an alternative embodiment of a dewatering box belonging to the dewatering unit relating to the invention.
  • the arrangement used in the solution relating to the invention comprises a headbox 1 from which the pulp is supplied to the Fourdrinier wire 2 which circulates via the breast roll 3 and the guide rolls 6 as an endless wire loop.
  • a forming board 4 and foil boxes 5 to effect mechanical dewatering.
  • a top wire 11 which circulates via the guide rolls 12 as a closed wire loop, inside which is arranged a non-vacuum dewatering unit 10.
  • the dewatering unit 10 comprises at least one dewatering box 13, described in greater detail below, and roll pairs 9, 20 of which there are two in succession in the embodiment shown.
  • the web is led past the hot-water boxes 30 and further to a so-called combipress 40 which comprises a first nip, a so-called lumb-breaker nip N1 , and a second nip N2 and a third nip N3, from where the web is led further, for example, to a shoe press 50, where the next nip N4 is located. From the shoe press 50 the web is led further on, for example, to an evaporation drying unit (not shown).
  • combipress 40 which comprises a first nip, a so-called lumb-breaker nip N1 , and a second nip N2 and a third nip N3, from where the web is led further, for example, to a shoe press 50, where the next nip N4 is located. From the shoe press 50 the web is led further on, for example, to an evaporation drying unit (not shown).
  • FIGS 2 and 2a show in greater detail a preferred structure of the dewatering box 13.
  • the dewatering box 13 is fixed, for example, with support means 60 to the frame structure in such a way that the position of the dewatering box with respect to the top wire is adjustable.
  • a dewatering strip 14 To the dewatering box is attached a dewatering strip 14, the tip part 19 of which can be placed against the top surface of the top wire 11 facing away from the web W in order to guide the water on the said surface upwards along the rising wall of the dewatering strip 14.
  • the angle of the strip 14 is adjustable.
  • At point 17 on the rising wall, in the direction of movement (arrow A) of the web W, is formed a forwards directed corner part after which the rising wall continues as a recessed wall part 15.
  • a loading table 7 comprising adjustable support strips 8 supported against the surface of the bottom wire facing away from the web, always on either side of the strip 14.
  • the length of the rising wall and the "detachment angle of the jet" and other dimensions are selected in such a way that the location of the detachment angle of the jet, in other words, the length of the rising wall is such that within the operating range of the apparatus (measured values), the rising water has a certain predetermined velocity (> 0 m/s) at the jet detachment angle.
  • the jet detachment angle refers, among other things, to the type of discontinuing part in the rising wall which prevents the flow from following the surface, that is, it detaches the flow from the surface and forms a substantially free jet.
  • the length of the rising wall is preferably less than about 100 mm, typically less than about 50 mm.
  • the recessed part deviates from the plane defined by the rising wall by about 5 mm, but it may also deviate from the said plane by more or less, for example, by only about 1 mm.
  • the dewatering box 113 comprises a dewatering strip 114, the tip part 119 of which can be placed against the upper surface of the top wire 11 to guide the water on it upwards along the rising wall of the dewatering strip 114.
  • the dewatering strip 114 is fixed to the T joint means 111 of the support part 112, in which support part 112 there is a surface 115, which is recessed with respect to the plane defined by the rising wall. In this way is formed a jet detachment corner part 117 between the dewatering strip 114 and the support part 112.
  • the water travelling upwards along the rising wall detaches from the rising wall and proceeds as a mainly upwards directed water jet 118, travelling further to the water collection space 116 from which the water can be passed on further, for example, to the wire basin.
  • the water can be scraped off the wire as a jet already at a speed of about 100 m/min, whereas for the water to rise directly along the surface requires a speed of about 200 m/min. Due to this solution, water can be collected at a lower speed without a vacuum system.
  • the dry matter content of the pulp web is increased to a value of approximately 3-10% before feeding the web into the space between the top wire and the bottom wire in which the dry matter content of the web is increased to a value of approximately 18-20% by utilising one or more dewatering boxes 13 relating to the invention and one or more roll nips N.
  • the roll nip N is preferably comprised of, for example, an upper roll 20 with a soft surface and a bored-through lower roll 9.

Landscapes

  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Wood Science & Technology (AREA)
  • Paper (AREA)
  • Drying Of Solid Materials (AREA)

Abstract

L'invention concerne un procédé permettant d'éliminer l'eau d'une bande continue de pâte (W) se déplaçant entre les toiles supérieure (11) et inférieure (2) sur la partie toile d'un séchoir de pulpe. Dans ce procédé, on utilise au moins une unité d'essorage ne se faisant pas sous vide (10). Cette unité d'essorage est disposée à l'intérieur de la toile supérieure (11) et comprend une bande d'essorage (14; 114), dont la pointe (19; 119) peut être mise en contact avec la surface de la toile supérieure (11) opposée à la bande continue (W) de façon à guider l'eau en direction ascendante, sur ladite surface, le long de la paroi ascendante de la bande d'essorage (14; 114), pour aboutir dans espace de reprise (16; 116) faisant partie de l'unité d'essorage. Dans ce procédé, l'eau guidée le long de la paroi ascendante au moyen de la pointe (19; 119) de la bande d'essorage (14; 114) s'écarte de la paroi ascendante de sorte que son mouvement ascendant prend sensiblement la forme d'un jet libre (18; 118). L'invention concerne également une unité d'essorage ne se faisant pas sous vide (10) permettant d'éliminer l'eau d'une bande continue de pâte (W) se déplaçant sur la partie toile d'un séchoir de pulpe.
PCT/FI2000/000518 1999-06-14 2000-06-09 Procede permettant d'eliminer l'eau de la partie toile d'un sechoir de pulpe et d'un unite d'essorage Ceased WO2000077298A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU50809/00A AU5080900A (en) 1999-06-14 2000-06-09 Method for removing water on the wire section of a pulp dryer and a dewatering unit

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FI991356A FI991356A7 (fi) 1999-06-14 1999-06-14 Menetelmä veden poistamiseksi sellunkuivatuskoneen viiraosalla ja vedenpoistoyksikkö
FI991356 1999-06-14

Publications (1)

Publication Number Publication Date
WO2000077298A1 true WO2000077298A1 (fr) 2000-12-21

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/FI2000/000518 Ceased WO2000077298A1 (fr) 1999-06-14 2000-06-09 Procede permettant d'eliminer l'eau de la partie toile d'un sechoir de pulpe et d'un unite d'essorage

Country Status (3)

Country Link
AU (1) AU5080900A (fr)
FI (1) FI991356A7 (fr)
WO (1) WO2000077298A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10207301B4 (de) * 2001-03-16 2006-01-12 Andritz Ag Verfahren und Vorrichtung zur Entfernung von Wasser aus einer Faserstoffbahn, Zellstoffbahn oder Papierbahn

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1986004368A1 (fr) * 1985-01-28 1986-07-31 Valmet Oy Procede et dispositif de production amelioree de papier sur la section de toile d'une machine a papier fourdrinier
WO1992004500A1 (fr) * 1990-09-05 1992-03-19 Sulzer-Escher Wyss Gmbh Ejecteur a fente, notamment pour machines a papier a deux toiles
US5116477A (en) * 1988-05-05 1992-05-26 Sulzer-Escher Wyss Gmbh Drainage device in a double-sieve mold
FI96876B (fi) * 1994-01-26 1996-05-31 Sunds Defibrator Pori Oy Pesumenetelmä
DE29822590U1 (de) * 1997-12-19 1999-02-25 Valmet Corp., Helsinki Siebpartie für eine Zellstofftrockenmaschine

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1986004368A1 (fr) * 1985-01-28 1986-07-31 Valmet Oy Procede et dispositif de production amelioree de papier sur la section de toile d'une machine a papier fourdrinier
US5116477A (en) * 1988-05-05 1992-05-26 Sulzer-Escher Wyss Gmbh Drainage device in a double-sieve mold
WO1992004500A1 (fr) * 1990-09-05 1992-03-19 Sulzer-Escher Wyss Gmbh Ejecteur a fente, notamment pour machines a papier a deux toiles
FI96876B (fi) * 1994-01-26 1996-05-31 Sunds Defibrator Pori Oy Pesumenetelmä
DE29822590U1 (de) * 1997-12-19 1999-02-25 Valmet Corp., Helsinki Siebpartie für eine Zellstofftrockenmaschine

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10207301B4 (de) * 2001-03-16 2006-01-12 Andritz Ag Verfahren und Vorrichtung zur Entfernung von Wasser aus einer Faserstoffbahn, Zellstoffbahn oder Papierbahn

Also Published As

Publication number Publication date
FI991356L (fi) 2000-12-15
FI991356A0 (fi) 1999-06-14
FI991356A7 (fi) 2000-12-15
AU5080900A (en) 2001-01-02

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