WO1996019615A1 - Procede et dispositif permettant de detecter et de modifier dans le sens transversal certaines proprietes determinees de bandes de papier - Google Patents

Procede et dispositif permettant de detecter et de modifier dans le sens transversal certaines proprietes determinees de bandes de papier Download PDF

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Publication number
WO1996019615A1
WO1996019615A1 PCT/DE1995/001791 DE9501791W WO9619615A1 WO 1996019615 A1 WO1996019615 A1 WO 1996019615A1 DE 9501791 W DE9501791 W DE 9501791W WO 9619615 A1 WO9619615 A1 WO 9619615A1
Authority
WO
WIPO (PCT)
Prior art keywords
fiber orientation
paper
paper web
formation
influencing
Prior art date
Application number
PCT/DE1995/001791
Other languages
German (de)
English (en)
Inventor
Jürgen ADAMY
Clemens Graf
Original Assignee
Siemens Aktiengesellschaft
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 Siemens Aktiengesellschaft filed Critical Siemens Aktiengesellschaft
Priority to DE59505937T priority Critical patent/DE59505937D1/de
Priority to EP95940956A priority patent/EP0799348B1/fr
Publication of WO1996019615A1 publication Critical patent/WO1996019615A1/fr
Priority to FI972576A priority patent/FI972576A0/fi

Links

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

Definitions

  • the invention relates to a method for detecting and influencing the cross profiles of certain properties of paper webs, such as in particular fiber orientation or formation, opacity, basis weight and / or shrinkage.
  • the invention also relates to the associated arrangement for carrying out this method for use in paper machines.
  • the uniformity of the paper properties across the production direction is decisive for the quality of paper.
  • the location-dependent profiles of the paper properties transversely to the direction of production are called cross profiles.
  • the monitoring and regulation of the paper properties require a measurement of these cross profiles.
  • the object of the invention is to create further improvements and to provide an associated arrangement.
  • the object is achieved in that at least the fiber orientation is continuously quantitatively measured and used to regulate the cross profile of the fiber orientation over the paper web when operating a paper machine becomes. If necessary, in addition to the fiber orientation, formation, opacity, basis weight and / or shrinkage are measured at the same time and their transverse profiles are determined.
  • a measuring head traversing the paper web is preferably used, which has an optical camera in addition to specific sensors. Such a camera is in particular a so-called CCD camera.
  • a control loop for fiber orientation is used to control the fiber orientation cross profile at the headbox of the paper machine.
  • a formation control loop is preferably formed from a so-called formation controller, a unit for mapping the paper web, a control path and a unit with associated sensors.
  • FIG. 1 is a top view of a paper web with an associated measuring head for measurement
  • FIG. 2 is a side view of the principle of a light transmission measurement with an additional light source
  • Figure 3 shows a diagram for defining the fiber orientation
  • Paper webs and the relevant measurand and Figure 4 is a block diagram of a formation control loop.
  • 1 denotes a paper web with the width b, which moves from the headbox of a paper machine (not shown in detail in the figures) in the x direction as the paper running direction.
  • the width b of the paper web 1 can be between 3 and 10 m and in particular be 5 m.
  • the speed of the paper web in the x direction is, for example, 1500 m / min.
  • a measuring head 10 is located on the paper web 1 at a distance without contact. All sensors for measuring the paper properties are spatially combined in the measuring head 10.
  • the measuring head 10 To detect cross profiles of certain properties of the paper web 1, the measuring head 10 is moved back and forth over the finished paper web 1 immediately before winding it up to form a coil. The measuring head 10 thus executes a movement traversing with time t. Because of the relative movement of the paper web 1 in the x-direction, the measuring head 10 covers a total zigzag path on the paper web 1.
  • the measuring head 10 usually contains a plurality of sensors known from the prior art, which are not dealt with in detail here.
  • An optical camera 11 is specifically added to the sensors already present in the measuring head 10.
  • a so-called CCD camera (charge coupled device) with electronic memories is advantageously used as the optical camera.
  • the camera 11 designed in this way enables simultaneous but independent measurement of the cross profiles of different paper properties, in particular of - fiber orientation
  • the properties indicated have the following meaning:
  • the fiber orientation is essential for the degree of fiber crosslinking in the paper web. Since the fiber crosslinking determines the strength of the paper web 1, efforts are often made to achieve good fiber crosslinking on the one hand and a uniform one on the other hand. In certain cases, one would also like to give the fiber orientation a preferred direction in order to achieve certain mechanical properties. For this purpose, the fiber orientation must be recorded and influenced locally in detail on the paper web 1.
  • a usable measurement of the fiber orientation is achieved on the basis of a camera recording. This results in an image at the respective measuring point.
  • the fiber orientation can be measured quantitatively by a suitable evaluation and, for example, an anisotropy factor can be defined.
  • FIG. 3 shows a measurement result for a paper web with a medium fiber orientation.
  • the angle of the fiber orientation is plotted on the abscissa and the relative frequency is plotted on the ordinate.
  • the angle of 90 ° points in the running direction of the machine (MR), the angles 0 and 180 ° point in the relevant transverse direction (QR) so perpendicular to it.
  • the anisotropy factor is the ratio of the frequency in the machine direction MR to the frequency in the transverse direction QR. If the fiber orientation is the same for all angles, an anisotropy factor of 1 results.
  • the anisotropy factor is> 1, for example 1.5, which means that there is a preferred direction of the fiber orientation in the running direction of the paper web 1.
  • the fiber orientation In order to obtain a signal that can be used for control purposes, the fiber orientation must be measured continuously and quasi-continuously.
  • the degree of fiber orientation and / or crosslinking is advantageously determined by a pattern recognition performed locally on the camera recording. Neural networks, for example, are suitable for this.
  • Formation is the small-area, non-uniform distribution of the fiber mass in the paper web 1 with local accumulation or thinning. In practice, it can be assessed on the basis of a so-called cloudiness when looking through the paper in front of a brightly illuminated surface. The formation can thus also be detected optically, and there may be a connection with the fiber orientation.
  • the translucency of paper is referred to as opacity. It is determined by a light transmission measurement in which the intensity of the light that has passed through the paper is measured. For this measurement, a light source is attached to the camera 11 on the other paper side of the paper web 1. The latter can be seen in detail from FIG. 2 that the measuring head 10 traverses back and forth with the camera 11 and a unit 15 with a light source below the paper web 1 carries out corresponding traversing movements.
  • the weight per unit area is the mass per unit area of the paper web 1, this size being specified in g / m 2 .
  • the basis weight cross profile can also be translucent
  • Paper can also be determined by a light transmission measurement with the camera 11.
  • the absolute value of the basis weight is not recorded, but only the mean value-free course of the basis weight cross profile is reproduced on the basis of the fluctuations in brightness.
  • the shrinkage inevitably results from paper production: in the drying area of the paper machine, water is removed from the paper pulp by passing the paper web 1 over metal rollers heated with steam. Drying can result in uneven shrinkage of the paper web 1 over its width b. If the actuators for basis weight and fiber orientation are in front of the drying section, the shrinkage undesirably changes the places of action of these actuators.
  • Controlling the fiber orientation cross profile on the paper web 1 requires knowledge of the assignment of each actuator to its place of action in the finished paper. This assignment is usually called "mapping".
  • the traversing camera 11 can achieve an overall image across the entire width of the paper web 1. In the form of stochastic irregularities on the upper side of the paper web 1, the impression of regular screen markings is included.
  • a complete control circuit 3 for fiber orientation consists in detail of a fiber orientation controller 31, a mapping unit 32, an actuator 33, a controlled system 34 and a sensor unit 35. These units are each only schematic (“black boxes”) shown, the signal feedback to the comparison point 30.
  • the mapping function of the unit 32 also takes into account the change in the assignment of the actuator 33 to the relevant actuator effect caused by shrinkage. Overall, the possibility of influencing the fiber orientation already suggested in the other context can thus be supplemented by the specified quantitative measurement of the fiber orientation to build up a complete control system. In the same way, the other significant properties of paper webs, such as formation, opacity and basis weight, can be incorporated into the control process, taking shrinkage into account.

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  • Paper (AREA)

Abstract

Pour décrire la qualité du papier, on a recours à des propriétés, généralement différentes, des bandes de papier, telles que, par exemple, l'orientation des fibres, la formation, l'opacité, le grammage et le retrait, propriétés dont chacune doit être déterminée. Conformément à l'invention, au moins l'orientation des fibres est mesurée quantitativement, en continu, sur la bande de paier, et est prise en compte pour le réglage du profil transversal de formation, lors du fonctionnement d'une machine à papier. Un dispositif approprié pour ce procédé est caractérisé par un circuit de régulation (3) servant à l'orientation des fibres.
PCT/DE1995/001791 1994-12-19 1995-12-14 Procede et dispositif permettant de detecter et de modifier dans le sens transversal certaines proprietes determinees de bandes de papier WO1996019615A1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
DE59505937T DE59505937D1 (de) 1994-12-19 1995-12-14 Verfahren zur erfassung und beeinflussung der querprofile bestimmter eigenschaften von papierbahnen und zugehörige anordnung
EP95940956A EP0799348B1 (fr) 1994-12-19 1995-12-14 Procede et dispositif permettant de detecter et de modifier dans le sens transversal certaines proprietes determinees de bandes de papier
FI972576A FI972576A0 (fi) 1994-12-19 1997-06-17 Menetelmä paperirainojen määrättyjen ominaisuuksien poikkileikkausprofiileihin liittyvien tietojen keräämiseksi sekä näihin ominaisuuksiin vaikuttamiseksi ja menetelmään liittyvä laitteisto

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DEP4445260.8 1994-12-19
DE4445260 1994-12-19

Publications (1)

Publication Number Publication Date
WO1996019615A1 true WO1996019615A1 (fr) 1996-06-27

Family

ID=6536248

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/DE1995/001791 WO1996019615A1 (fr) 1994-12-19 1995-12-14 Procede et dispositif permettant de detecter et de modifier dans le sens transversal certaines proprietes determinees de bandes de papier

Country Status (5)

Country Link
EP (1) EP0799348B1 (fr)
AT (1) ATE180026T1 (fr)
DE (1) DE59505937D1 (fr)
FI (1) FI972576A0 (fr)
WO (1) WO1996019615A1 (fr)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0826821A2 (fr) * 1996-08-30 1998-03-04 Voith Sulzer Papiermaschinen Gesellschaft mbH Dispositif de commande comprenant plusieurs capteurs
WO1998028490A1 (fr) * 1996-12-20 1998-07-02 Siemens Aktiengesellschaft Procede et dispositif pour conduire un processus lors de la fabrication de papier
WO1999056112A1 (fr) * 1998-04-23 1999-11-04 Isover Saint-Gobain Procede pour la determination de l'orientation de la structure des fibres de matelas de laine minerale
GB2342457A (en) * 1998-10-07 2000-04-12 John Clark A quality control sampling system with barcode reader and video camera
EP0995834A1 (fr) * 1998-09-24 2000-04-26 Voith Sulzer Papiertechnik Patent GmbH Procédé et dispositif pour améliorer le profil transversal du rétrécissement dans une machine à papier
WO2003072874A1 (fr) * 2002-02-21 2003-09-04 Abb Ltd. Commande en boucle fermee d'orientation de fibre en ligne

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1988005099A1 (fr) * 1986-12-30 1988-07-14 Niemi, Ulla, Riitta, Anneli Procede et appareil pour regler la ligne seche sur la toile d'une machine a papier du type fourdrinier
DE3827084C1 (fr) * 1988-08-10 1989-11-16 Sulzer-Escher Wyss Gmbh, 7980 Ravensburg, De
EP0401188A2 (fr) * 1989-06-01 1990-12-05 Valmet Paper Machinery Inc. Système de contrôle pour une machine à papier ou carton
EP0408894A2 (fr) * 1989-07-17 1991-01-23 Valmet Paper Machinery Inc. Procédé de régulation et de mesurage en ligne de l'orientation des fibres dans une bande fabriquée sur une machine à papier
JPH0337556A (ja) * 1989-07-05 1991-02-18 Mitsubishi Heavy Ind Ltd 紙質測定装置
DE4005281A1 (de) * 1990-02-20 1991-08-22 Schultz Hans Joachim Dr Ing Stoffauflauf mit regelung des flaechengewicht-querprofiles ueber die verduennung der fasersuspension
DE4008282A1 (de) * 1990-03-15 1991-09-19 Voith Gmbh J M Massnahmen zur erfassung der schrumpfung oder dehnung von warenbahnen
WO1992020861A1 (fr) * 1991-05-23 1992-11-26 Niemi, Ulla, Riitta, Anneli Procede et appareil de commande de la ligne seche ou de commande basee sur la ligne seche dans une machine a papier fourdrinier
DE4221031A1 (de) * 1992-06-26 1994-01-05 Voith Gmbh J M Einrichtung zur berührungsfreien Dickenmessung von dünnen Substraten

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1988005099A1 (fr) * 1986-12-30 1988-07-14 Niemi, Ulla, Riitta, Anneli Procede et appareil pour regler la ligne seche sur la toile d'une machine a papier du type fourdrinier
DE3827084C1 (fr) * 1988-08-10 1989-11-16 Sulzer-Escher Wyss Gmbh, 7980 Ravensburg, De
EP0401188A2 (fr) * 1989-06-01 1990-12-05 Valmet Paper Machinery Inc. Système de contrôle pour une machine à papier ou carton
JPH0337556A (ja) * 1989-07-05 1991-02-18 Mitsubishi Heavy Ind Ltd 紙質測定装置
EP0408894A2 (fr) * 1989-07-17 1991-01-23 Valmet Paper Machinery Inc. Procédé de régulation et de mesurage en ligne de l'orientation des fibres dans une bande fabriquée sur une machine à papier
DE4005281A1 (de) * 1990-02-20 1991-08-22 Schultz Hans Joachim Dr Ing Stoffauflauf mit regelung des flaechengewicht-querprofiles ueber die verduennung der fasersuspension
DE4008282A1 (de) * 1990-03-15 1991-09-19 Voith Gmbh J M Massnahmen zur erfassung der schrumpfung oder dehnung von warenbahnen
WO1992020861A1 (fr) * 1991-05-23 1992-11-26 Niemi, Ulla, Riitta, Anneli Procede et appareil de commande de la ligne seche ou de commande basee sur la ligne seche dans une machine a papier fourdrinier
DE4221031A1 (de) * 1992-06-26 1994-01-05 Voith Gmbh J M Einrichtung zur berührungsfreien Dickenmessung von dünnen Substraten

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 15, no. 172 (P - 1197) 30 April 1991 (1991-04-30) *

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0826821A2 (fr) * 1996-08-30 1998-03-04 Voith Sulzer Papiermaschinen Gesellschaft mbH Dispositif de commande comprenant plusieurs capteurs
EP0826821A3 (fr) * 1996-08-30 1999-06-16 Voith Sulzer Papiermaschinen Gesellschaft mbH Dispositif de commande comprenant plusieurs capteurs
US6179964B1 (en) 1996-08-30 2001-01-30 Voith Sulzer Papiermaschinen Gmbh Method and control device for paper web profile control with plurality of sensors
WO1998028490A1 (fr) * 1996-12-20 1998-07-02 Siemens Aktiengesellschaft Procede et dispositif pour conduire un processus lors de la fabrication de papier
WO1999056112A1 (fr) * 1998-04-23 1999-11-04 Isover Saint-Gobain Procede pour la determination de l'orientation de la structure des fibres de matelas de laine minerale
EP0995834A1 (fr) * 1998-09-24 2000-04-26 Voith Sulzer Papiertechnik Patent GmbH Procédé et dispositif pour améliorer le profil transversal du rétrécissement dans une machine à papier
US6303001B1 (en) 1998-09-24 2001-10-16 Voith Sulzer Papiertechnik Patent Gmbh Process for improving the shrinkage cross direction profile and paper having an improved cross
EP1323862A1 (fr) * 1998-09-24 2003-07-02 Voith Paper Patent GmbH Procédé pour régler le profil transversal du rétrécissement dans une machine à papier
GB2342457A (en) * 1998-10-07 2000-04-12 John Clark A quality control sampling system with barcode reader and video camera
WO2003072874A1 (fr) * 2002-02-21 2003-09-04 Abb Ltd. Commande en boucle fermee d'orientation de fibre en ligne

Also Published As

Publication number Publication date
ATE180026T1 (de) 1999-05-15
DE59505937D1 (de) 1999-06-17
EP0799348A1 (fr) 1997-10-08
FI972576A (fi) 1997-06-17
EP0799348B1 (fr) 1999-05-12
FI972576A0 (fi) 1997-06-17

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