EP1426488A1 - Dispositif de formation d'une bande fibreuse - Google Patents

Dispositif de formation d'une bande fibreuse Download PDF

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Publication number
EP1426488A1
EP1426488A1 EP03104534A EP03104534A EP1426488A1 EP 1426488 A1 EP1426488 A1 EP 1426488A1 EP 03104534 A EP03104534 A EP 03104534A EP 03104534 A EP03104534 A EP 03104534A EP 1426488 A1 EP1426488 A1 EP 1426488A1
Authority
EP
European Patent Office
Prior art keywords
fibrous web
measuring
section
twin
drainage
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
EP03104534A
Other languages
German (de)
English (en)
Inventor
Stefan Lehner-Dittenberger
Alfred Dr. Bubik
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 Patent GmbH
Original Assignee
Voith Paper Patent 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 Paper Patent GmbH filed Critical Voith Paper Patent GmbH
Publication of EP1426488A1 publication Critical patent/EP1426488A1/fr
Ceased legal-status Critical Current

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Classifications

    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21G—CALENDERS; ACCESSORIES FOR PAPER-MAKING MACHINES
    • D21G9/00—Other accessories for paper-making machines
    • D21G9/0009—Paper-making control systems
    • D21G9/0027—Paper-making control systems controlling the forming 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
    • D21F1/48—Suction apparatus
    • 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 device for producing a fibrous web, in particular a paper web, from a fiber suspension with a twin wire former, which has two interacting sieve belts.
  • Such a device is from DE 44 02 274 A1 (PB10044 DE) of the applicant known.
  • the known device is suitable for forming a multilayer or multi-layer paper or cardboard web. The situation changes a third sieve merged with another layer.
  • this object is achieved according to the invention solved in that a measuring arrangement for measuring a property the fibrous web arranged in the area or in the vicinity of the twin wire former is and that the measured property of a control unit as an actual variable feeds, wherein the control unit has a production parameter for manufacturing regulates the fibrous web.
  • the invention is used in twin wire formers, that is to say both in gap (gap) formers. Shaping as well as with Hyridformers. These are in front of the twin wire section a slow drainage pre-drainage section is available.
  • the twin-wire section itself is equipped with a so-called top sieve box, which with Vacuum is applied. The ones withdrawn from the top screen box and out of this The amount of water removed is often used as a measure of the quality of the formation to be produced Paper or cardboard.
  • This amount of water can be used, for example, with inductive flow meters measure and primarily serves to monitor the drainage process.
  • the throughput to be set for the production of a fibrous web depends heavily on the basis weight, on the machine speed, on the Retention and other sizes. For the same basis weight of a web, which is produced at different machine speeds there are very different dependencies.
  • Figure 1 the formation F as a function of throughput Q in a top sieve box Twin-wire former shown, as for example from the above DE 44 02 274 A1 (PB10044 DE) of the applicant is known. This results in for the same basis weight, different curves for different Machine speeds.
  • the Formation values and technological properties that is properties the fibrous web such as the degree of whiteness, the opacity, the strength, etc. are independent on the machine speed and are optimally in one Range between 2 and 4% dry matter in front of the twin wire former, in particular in front of a hybrid former.
  • the measurement of the average consistency or the formation of the fibrous web, such as done according to the invention is much more reliable and accurate, to affect the formation of the fibrous web than the derivative these quantities from the discharged water quantities or similar methods.
  • the dry content can be measured by measuring the material density in front of the twin wire former influenced in the mold run-in and thus decisively influenced the formation become.
  • the device according to the invention works independently of the Machine speed and the basis weight of the fibrous web. dead are shortened and the control characteristic is improved.
  • the measuring arrangement is the twin wire former is upstream and / or downstream.
  • the measuring arrangement comprises at least one sensor for measuring a physical, chemical or technological property of the fibrous web.
  • a device in which the measuring arrangement is particularly suitable in a pre-dewatering section upstream of the twin wire former is arranged.
  • the pressure level is used as the controlled variable or the vacuum of a closed box or several closed boxes Boxes of the pre-drainage section is used.
  • Fibrous web on the basis of a target dryness determined by the control unit Fibrous web one of the first in the material flow direction of the fibrous web arranged boxes of the pre-drainage section for setting the Dry content of the fibrous web can be used.
  • a high controllability of the formation of the fibrous web succeeds when in one Embodiment of the invention in the material flow direction of the fibrous web last boxes of the pre-drainage section with a low Vacuum level, especially less than 0.05 bar, or with a light one Overpressure, in particular less than 0.005 bar, operated.
  • the function of the control unit is supported if the twin wire former has a Measuring arrangement for measuring the mass of at least one of the sieve belts in Material flow direction is subordinate to the fibrous web and that of the Measuring arrangement measured value for determining the controlled variable in the control unit, in particular for controlling the pressure in one of the boxes of the pre-drainage section is used.
  • An advantageous embodiment of the device according to the invention has in one Siebschlaufabrough at least one of the sieve belts an arrangement for Cleaning the filter belt, in particular a pipe suction device, a brush, or the like, on.
  • An ultrasonic sensor is particularly suitable, especially in one Pre-dewatering section or in the twin-wire section, a gamma emitter, especially in the pre-dewatering section or Post-drainage section or to determine the mass in the Return section, or a transmitted light sensor, especially in the Post-drainage section, which does not exclude that other Detectors or sensors can be used.
  • the device according to the invention is used, in the area between a press downstream of the twin wire former and one Drying device a measuring point for determining the vacuum in one Upper sieve box is arranged.
  • a measuring point in the area after a Press and / or additionally in front of or within a drying device Measuring point to improve the vacuum in a drainage box inside an endless screen of an insert former is present.
  • the fibrous suspension i.e. the medium
  • the device is assigned at least one headbox, which preferably comprises at least one lamella arranged in its nozzle.
  • the measured value signals are generally falsified by short-term masses or basis weight deviations, measured behind the press or in the dryer section, short-term changes in the suspension height in front of the twin-wire former or changes in speed or mass deviations in the twin-wire former. The result in the form of short-term changes, random variations or even noise are greatly reduced by a headbox with at least one lamella.
  • a device for producing a fibrous web from a fibrous suspension which is applied via a headbox 1 (FIG. 3) to a lower endless sieve (wire belt) 7 rotating over rollers 2 to 6 and a forming roller FW
  • a pre-dewatering section a and a twin-wire section b there are a post-drainage section c and a screen return section d are present.
  • the endless wire 7 runs below an upper endless wire (wire belt) 8, the fibrous web being transported further between the two endless wires 7, 8 and being dewatered at the same time.
  • a drainage box 9 or 10 is arranged within the endless screens 7, 8.
  • the device shown can be designed, for example, in a further embodiment, such as the twin-wire former shown in the German patent application DE 40 05 420 A1 (PB04713 DE) by the applicant.
  • the content of this published specification is hereby made the subject of the present description.
  • the endless screen (sieve belt) 8 can also be guided over only two or three rollers.
  • Such a screen guide (dashed line for three rollers) is shown, for example, in the applicant's German Offenlegungsschrift DE 198 09 480 A1 (PB10668 DE).
  • the content of this published specification is hereby also made the subject of the present description.
  • the device is assigned a headbox 1, which is arranged in its nozzle 12 Includes lamella 13. It can of course also in the nozzle 12 several slats and / or slats with different lengths, surface properties and the like. Furthermore, the slats also protrude beyond the end of the nozzle 12.
  • a sieve table Within the pre-dewatering section a are a sieve table, several foil boxes and drainage boxes a1, a2, ... arranged. Only four are shown Drainage boxes a1 to a4. However, there may be n drainage boxes be operated with a vacuum or with a slight positive pressure. Preferably four to five drainage boxes are a1 to a4 respectively a5 available, for example 500 each in the running direction of the fibrous web mm are wide. The proportion of their open area is 30 to 55%, based on their entire surface.
  • the drainage boxes a1 to a4 face upwards a flat or an upward curved surface. You work with or without negative pressure or positive pressure.
  • the vacuum is between 0 and 0.2 bar, the overpressure between 0 and 0.005 bar.
  • the distance of the drainage boxes a1 to a4 is 20 to 500 mm.
  • the drainage boxes a1, a2, ... there are measuring stations A1, A2, A3, ... for measuring the dry content T in the pre-dewatering section a arranged.
  • the drainage boxes a1, a2, .. are used Wet suction boxes, vacuum foil boxes, iso-flow boxes, flat suction boxes, etc. Boxes of this type can also be placed within the lower endless sieve 7 Arrange below the endless sieve 8.
  • At the measuring stations A1, A2, ... are for example ultrasonic detectors or gamma emitters for determining the Dry content T of the fibrous web is present.
  • the pressure level or Vacuum of one or more of the closed drainage boxes a1, a2, ... used in the pre-drainage section a If in the fibrous web Due to the circulatory system, for example, add more fines than desired Dryness T of the fibrous web reduced. This is accomplished by using the vacuum is increased ( Figure 2). This measure makes the desired one the same optimal formation F as a function of the dry content T reached.
  • the following Boxes a3, a4 are kept at a constant low due to the process Vacuum level kept, for example, less than 0.05 bar. Or they work at a low excess pressure of, for example, less than 0.005 bar, so the pre-dewatered fibrous web or the filter cake are not closed highly compressed enters the twin wire zone b.
  • the forming strips are in the area of the twin-wire drainage zone arranged, such as from DE 43 30 546 A1 (PB04959 DE) of the applicant is known.
  • the number of molding strips can also be reduced, for example on 3 or 4. This allows time-dependent signs of wear on the endless screens 7, 8 and on the forming strips.
  • To the measured values at the measuring stations A1, A2, A3, ... insensitive to To measure screen wear is a measurement of the screen mass, for example by means of a gamma emitter at a measuring point C in the area of the screen return section d of the endless screen 7 made.
  • a gamma emitter at a measuring point C in the area of the screen return section d of the endless screen 7 made.
  • the pressure level in the drainage boxes can be measured using this measured value Control a1, a2, a3, ... and thus regulate the formation quality.
  • a cleaning device before the measuring point C such as a pipe suction device 11 or a brush or a similar device arranged, the endless filter 7 sucks, wipes or blows dry.
  • Another or additional possibility for measuring the formation is in the post-drainage section c, i.e. behind the twin-wire area b.
  • the Formation of the fibrous web is there for example by means of transmitted light or Ultrasonic detectors detected and with the vacuum or pressure in the drainage boxes regulated. In this way, the formation quality FG gain as a function of a pressure p in one of the drainage boxes b1, b2, b3, ... ( Figure 4).
  • twin wire section b (FIG. 3) there is also that inside the endless wire 8 arranged upper suction box or drainage box 9 either with flat or curved upward surface.
  • the bottom screen suction box 10 is also either straight or curved. possibly it has elastic strips.
  • a device for producing a two-layer fibrous web (FIG. 5) (Testliner machine) two headboxes 20, 21 are arranged, of which Headbox 20 the ceiling and of the headbox 21 the back of the fibrous web (Testlinerbahn) manufactured. Endless screens 22, 23 and 24 are provided for this purpose.
  • a controllable or adjustable suction box 23a arranged within the endless screen 23. The vacuum is measured in via a measuring arrangement A10 a drainage box 25 and thus regulated the formation of the back and maximized. This can lower the basis weight of the expensive ceiling being held.
  • An alternative is to measure the formation in the area of a downstream press 26 or a dryer section 27 at a measuring point B10.
  • the formation of a three or multi-layer cardboard web improved by means of headboxes 30, 31, 32 ( Figure 6) and several endless screens 33 to 36 is produced.
  • the headbox 30 is used to cover the ceiling, by means of the headbox 31 the insert and by means of the headbox 32 the back generated.
  • the cardboard web is then fed to a press 37.
  • a coating and drying device 39 turns the vacuum into drainage boxes 40, 41 improved within the endless screen 34 of the insert former optimized.

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  • Paper (AREA)
EP03104534A 2002-12-07 2003-12-04 Dispositif de formation d'une bande fibreuse Ceased EP1426488A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE2002157293 DE10257293A1 (de) 2002-12-07 2002-12-07 Vorrichtung zur Herstellung einer Faserstoffbahn
DE10257293 2002-12-07

Publications (1)

Publication Number Publication Date
EP1426488A1 true EP1426488A1 (fr) 2004-06-09

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EP03104534A Ceased EP1426488A1 (fr) 2002-12-07 2003-12-04 Dispositif de formation d'une bande fibreuse

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EP (1) EP1426488A1 (fr)
DE (1) DE10257293A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102008040688A1 (de) 2008-07-24 2010-01-28 Voith Patent Gmbh Verfahren zur Optimierung der Energiebilanz in Formiereinheiten in Maschinen zur Herstellung von Faserstoffbahnen und Formiereinheit
US7833386B2 (en) 2005-08-12 2010-11-16 Voith Patent Gmbh Method for producing a fibrous web and twin mesh former for performing said method

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102012204067A1 (de) * 2012-03-15 2013-09-19 Voith Patent Gmbh Verfahren zur Steuerung oder Regelung eines Faserstoffbahnherstellungsprozesses

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1063348A2 (fr) * 1999-06-26 2000-12-27 Wilbanks International, Inc. Machine à papier avec lames d'égouttage variables
US6168687B1 (en) * 1998-04-24 2001-01-02 Honeywell-Measurex Corporation System and method for sheet measurement and control in papermaking machine
WO2002046523A1 (fr) * 2000-12-07 2002-06-13 Metso Paper, Inc. Procede et dispositif de reglage du profil plein d'une bande dans une toile de fabrication d'une machine a papier/carton
WO2003040465A1 (fr) * 2001-11-09 2003-05-15 Metso Automation Oy Procede et appareil pour ajuster le fonctionnement d'une partie toile

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6168687B1 (en) * 1998-04-24 2001-01-02 Honeywell-Measurex Corporation System and method for sheet measurement and control in papermaking machine
EP1063348A2 (fr) * 1999-06-26 2000-12-27 Wilbanks International, Inc. Machine à papier avec lames d'égouttage variables
WO2002046523A1 (fr) * 2000-12-07 2002-06-13 Metso Paper, Inc. Procede et dispositif de reglage du profil plein d'une bande dans une toile de fabrication d'une machine a papier/carton
WO2003040465A1 (fr) * 2001-11-09 2003-05-15 Metso Automation Oy Procede et appareil pour ajuster le fonctionnement d'une partie toile

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7833386B2 (en) 2005-08-12 2010-11-16 Voith Patent Gmbh Method for producing a fibrous web and twin mesh former for performing said method
DE102008040688A1 (de) 2008-07-24 2010-01-28 Voith Patent Gmbh Verfahren zur Optimierung der Energiebilanz in Formiereinheiten in Maschinen zur Herstellung von Faserstoffbahnen und Formiereinheit
WO2010010109A1 (fr) * 2008-07-24 2010-01-28 Voith Patent Gmbh Procédé d'optimisation du bilan énergétique des unités de formage dans des machines de fabrication de bandes de matières fibreuses, ainsi qu'unité de formage
US8323452B2 (en) 2008-07-24 2012-12-04 Voith Patent Gmbh Method for optimizing the energy balance in forming sections in machines for the production of fibrous webs, and forming section using control elements associated with dewatering units
CN102105635B (zh) * 2008-07-24 2012-12-05 沃依特专利有限责任公司 用于优化制造纤维幅的机器中的成形单元中的能量平衡的方法以及成形单元
US8349136B2 (en) 2008-07-24 2013-01-08 Voith Patent Gmbh Method for optimizing the energy balance in forming sections in machines for the production of fibrous webs, and forming section

Also Published As

Publication number Publication date
DE10257293A1 (de) 2004-09-09

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