EP1893809B1 - Method and device for the improvement of paper quality - Google Patents

Method and device for the improvement of paper quality Download PDF

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Publication number
EP1893809B1
EP1893809B1 EP06763592A EP06763592A EP1893809B1 EP 1893809 B1 EP1893809 B1 EP 1893809B1 EP 06763592 A EP06763592 A EP 06763592A EP 06763592 A EP06763592 A EP 06763592A EP 1893809 B1 EP1893809 B1 EP 1893809B1
Authority
EP
European Patent Office
Prior art keywords
paper
plasma
process material
voltage
roll
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.)
Not-in-force
Application number
EP06763592A
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German (de)
French (fr)
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EP1893809A2 (en
Inventor
Helmut Figalist
Werner Hartmann
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.)
Siemens AG
Siemens Corp
Original Assignee
Siemens AG
Siemens Corp
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Publication date
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Publication of EP1893809A2 publication Critical patent/EP1893809A2/en
Application granted granted Critical
Publication of EP1893809B1 publication Critical patent/EP1893809B1/en
Anticipated expiration legal-status Critical
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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
    • D21C11/00—Regeneration of pulp liquors or effluent waste waters
    • D21C11/12—Combustion of pulp liquors
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F3/00—Press section of machines for making continuous webs of paper
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F5/00—Dryer section of machines for making continuous webs of paper
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H25/00—After-treatment of paper not provided for in groups D21H17/00 - D21H23/00
    • D21H25/04—Physical treatment, e.g. heating, irradiating
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21J—FIBREBOARD; MANUFACTURE OF ARTICLES FROM CELLULOSIC FIBROUS SUSPENSIONS OR FROM PAPIER-MACHE
    • D21J1/00—Fibreboard

Definitions

  • the invention relates to a device for guiding and / or deflecting and / or pressing and / or rolling up and / or finishing a process material in the production of paper, paperboard or cardboard or in a treatment whose properties change treatment.
  • the invention also relates to a device for guiding and / or diverting and / or pressing and / or rolling up and / or finishing a process material in the production of paper, paperboard or cardboard or in the case of a property-altering treatment comprising one in contact with the process material coming roll.
  • the invention relates to a method for producing or treating a process material in the production or treatment of paper, cardboard or cardboard, preferably for operating a device according to the invention, wherein the process material is brought into contact with preferably non-thermal, large-area plasma under atmospheric pressure, the plasma is generated in the immediate vicinity of the process material or in the process material or in its immediate vicinity, a gas discharge, in particular a corona discharge, is generated under atmospheric pressure.
  • a paper manufacturing plant or in parts of a papermaking plant leaves a usually still wet paper, cardboard or cardboard a screen area of the papermaking plant and from there into a Pressenbe rich of paper making plant. In the press area, the paper, cardboard or cardboard is drained.
  • a surface-friendly drying of the paper e.g. Infrared drying and / or air drying.
  • a treatment for improving the surface quality with non-thermal, "cold plasmas" is already known.
  • the previous methods use this low-pressure plasma reactors, which are technically very complicated because of the necessary vacuum generation. Atmospheric printing processes, as they are needed in the paper industry to master the usual process speeds today, are not yet known.
  • EP 1 067 433 A1 It is known to use an oscillating high voltage to generate the plasma between the electrodes, wherein a continuous high voltage field is generated by means of an AC voltage generator.
  • the invention has for its object to provide an apparatus and a method available to further increase the paper quality in papermaking.
  • the device-related object is achieved by at least two electrodes for generating a plasma in the process material or in its immediate surroundings, wherein the two electrodes are arranged on mutually opposite sides of the process material.
  • the object is achieved by the second device mentioned above in that the roller is prepared as a first electrode, wherein in the process material or in its immediate vicinity, a plasma can be generated.
  • a second electrode is arranged relative to the roller such that the process material can be transported or guided between the roller, in particular the first electrode, and the second electrode.
  • the paper or process material between the roller, which is prepared as a first electrode, and the second electrode can be treated with plasma in an advantageous manner.
  • the roller is arranged such that it comes into contact with the process material, preferably a formed sheet, preferably a pressed sheet, in particular a paper web.
  • the process material preferably a formed sheet, preferably a pressed sheet, in particular a paper web.
  • the roller is designed as an electrode in the device according to the invention, the running over her Process material to be treated with plasma. Even existing older refining plants can be beneficial be upgraded by replacing the device according to the invention against the conventional transport rollers, and thus provide the paper with an increased quality.
  • a second roller is expedient, wherein the second roller is arranged relative to the roller in such a way that a flat process material, in particular the paper web, comes into contact with the rollers on both sides. If the paper is guided quasi slalom-like by means of various transport rollers through a finishing machine, it is in terms of effective treatment of advantage to arrange the electrodes configured as electrodes one behind the other, that the paper can be treated successively in time from both sides with plasma.
  • roller is prepared with a gas-permeable surface.
  • the roll is adapted to radially supply a gas stream.
  • a gas stream preferably finely divided air bubbles or oxygen or oxygen are mixed with a carrier gas, e.g. Argon, flowed into the roller, which in turn can penetrate through the gas-permeable surface in the paper.
  • a carrier gas e.g. Argon
  • the device can be configured with a means for flowing the process material with a gas stream. Taking advantage of the advantages already mentioned, the gas stream is conducted directly into the treatment space, ie between the two electrodes.
  • the said electrodes or rollers generate the plasma in a particularly advantageous manner by means of a high-voltage pulse generator which is connected to the electrode (s).
  • the plasma or a pulsed corona discharge directly above and / or below the paper using extremely short high voltage pulses of less than 10 microseconds, in particular 1 microseconds, and particularly advantageously significantly less than 1 microseconds with voltages of a few kV to over 100 kV, depending on Distance of the electrodes and the properties of the paper can be produced in an advantageous manner.
  • the process material is brought into contact with the plasma on both sides or treated on both sides by means of the gas discharge.
  • the process material is brought into contact with the plasma on both sides or treated on both sides by means of the gas discharge.
  • it is of particular advantage that with a simultaneous or approximately simultaneous two-sided treatment of the process material with plasma or a gas discharge which inter alia has a surface-altering effect or intervenes in the molecular structure of the process material that the process material is changed homogeneously. This means that possibly occurring inhomogeneities or stress states in the process material are avoided.
  • the process material at the same time partially acts as a dielectric barrier, which can better suppress a transition from a streamer to a breakdown.
  • a still unpressed and / or moist sheet or dry sheet is used in a paper or board production process as process material.
  • high-voltage pulses with a duration of less than 10 ⁇ s are preferably generated.
  • RF radio frequency
  • radicals are generated (OH - , HOO, O 3 ), which react chemically with the paper surface.
  • Radicals may, inter alia, also trigger bleaching chemical reactions, in particular free oxygen O, in particular also a hydroxyl radical OH, in particular ozone O 3 , as well as free functional groups such as OH groups, COOH groups.
  • These functional groups are significantly involved, in particular to increase the bond strength of the fibers with each other, which increases a tear strength of the paper and thus a possible processing speed.
  • the functional groups have the property to increase the binding to dyes and the wettability of paper, which can be targeted control and improve the subsequent printability of the paper.
  • Radicals are generated in gas discharges by high-energy electrons collide with molecules and thereby dissociate or excite them and thus lead to radical formation. In the dissociation, radicals are released immediately, while the excitation by subsequent radiant transitions UV light is generated, which in turn reacts with and preferably dissociates air and water molecules.
  • eV electron volts
  • UV light is generated, which in turn reacts with and preferably dissociates air and water molecules.
  • eV electron volts
  • streamers are discharge channels that are under construction and form due to the applied high external field strengths. An assembly of such streamer takes place within less than 10 ns and then rapidly merges into a thermal breakdown channel.
  • the pulse duration is significantly shorter than corresponds to a build-up time of a complete breakdown in the respective medium.
  • the paper web or the process material is located between the electrodes used for the streamer discharge, this is particularly advantageous because the paper or the process material thereby partially acts as a dielectric barrier.
  • the dielectric barrier makes it easier to control the transition from the streamer to the breakdown.
  • FIG. 1 shows a schematic representation of a papermaking plant 1, as used in today's paper mills. Their construction and the combination of different aggregates are determined by the type of paper, board and paperboard types to be produced, as well as the raw materials used.
  • the papermaking plant 1 has a spatial extent of about 10 m in width and about 120 m in length. It takes only a few seconds from the first impact of a fiber suspension or pulp 39 on a screening device 9 to the finished paper 27, which is finally rolled up in a reel 15. The entire papermaking process is essentially subdivided into the areas of stock preparation, paper machine, finishing and equipment.
  • a headbox 7 of the papermaking plant 1 distributes the pulp suspension uniformly over the entire wire width.
  • the paper web 27 still contains about 80% water.
  • Another dewatering process is carried out by mechanical pressure in the press device 11.
  • the paper web 27 is passed between rollers made of steel and thereby dewatered.
  • the press device 11 is followed by a drying system 13.
  • the remaining residual water is evaporated in the drying plant 13.
  • Slalom-like, the paper web 27 passes through several steam-heated drying cylinders. In the end, the paper 27 has a residual moisture of a few percent.
  • resulting water vapor is sucked off and passed into a heat recovery system, not shown.
  • a first electrode 47 and a second electrode 48 are arranged in the press apparatus 11 such that the paper web is guided by means of a transport roller 12 between the two electrodes 47, 48 and treated simultaneously with plasma.
  • the electrodes 47 and 48 are connected to a high-voltage pulse generator 46.
  • a high-voltage pulse generator 46 By means of this high-voltage pulse generator 46, a large-volume plasma with a large cross section and with a high power density is generated between the electrodes 47 and 48.
  • a plasma density is homogeneously distributed over the treatment area which is covered by the electrodes 47 and 48.
  • the large-volume plasma with high power density is generated by means of the inventive arrangement in that a DC corona discharge intensive, short-lasting high voltage pulses are superimposed with a high pulse repetition rate of 1 kH.
  • a very homogeneous, large-volume plasma with a high power density is produced without the plasma constrictions that are known in DC corona discharges.
  • oxygen is introduced by means of a gas distributor 81 via a gas line 80 with argon as carrier gas into the treatment space between the electrodes 47 and 48.
  • Hydroxyl radicals are particularly advantageously produced with the aid of the oxygen-argon mixture. Hydroxyl radicals are particularly aggressive and oxidizing, thereby lingering only a few seconds in the treatment area between the electrodes 47 and 48 Paper web 27 achieved an increase in quality properties.
  • the first electrode 47 in the press apparatus 11 is designed as a semicircular grid electrode. Due to the semicircular configuration of the electrode 47, it can follow the course of the paper web over the transport roller 12.
  • the second electrode 48 in the press apparatus 11 is configured as a plate electrode and arranged such that the transport roller 12 is guided between the electrodes 47 and 48.
  • the pressing process compacts the paper structure, the strength is increased again and a surface quality is decisively influenced. Further, by treating the pressed paper 27 with cold plasma, particularly with generated radicals, the molecular structure of the paper surface is further changed. In addition to increasing the strength of the paper 27, a later printability is improved.
  • a streamer is a special form of a linearly moving plasma cloud or a developing discharge channel that forms due to the excited high external field strength.
  • An assembly of such streamer takes place within less than 10 ns and merges very quickly into a thermal breakdown channel.
  • the aforesaid arrangement of the electrode system, with the paper web 27 between the electrodes used for the streamer discharge, is particularly advantageous, as the paper 27 thereby partially acts as a dielectric barrier, whereby the transition from the streamer to the breakdown can be suppressed.
  • the radicals O 3 , H 2 , O 2 , OH, HO 2 and HO 2 - produced in the immediate vicinity of the paper web.
  • these radicals trigger a bleaching chemical reaction.
  • the high voltage pulse generator 46 is operated to generate voltage pulses having a duration of typically 1 ⁇ s between the electrodes 47 and 48.
  • a necessary for the generation of radicals and ozone in the paper web and in the immediate vicinity of the paper web DC voltage is about 10 kV to some 100 kV.
  • the high voltage pulses are superimposed on the DC voltage to form a total amplitude of a few 100 kV.
  • FIG. 2 shows as a further embodiment, a sectional view of an arrangement for generating radicals.
  • a high voltage electrode 50 is arranged in the center of the arrangement.
  • the outer jacket of the assembly is prepared as a counter electrode 51.
  • the arrangement contains a pulp fiber suspension 39 to be screened.
  • a streamer 53 is shown between the electrodes 50 and 51. Radicals are generated in streamers by the collision of energetic electrons with molecules, thereby disassociating or exciting them. Upon dissociation, radicals 59 are immediately released, while upon excitation by a subsequent radiant transition, UV light is generated. This generated UV light in turn reacts with water molecules and dissociates them.
  • FIG. 3 is the applied voltage waveform of the high voltage pulses shown.
  • a first pulse 66 and a second pulse 67 each having a pulse width 62, have a spacing of one pulse repetition time 63.
  • the abscissa shows the time in milliseconds and the ordinate the voltage in kV. The units are chosen arbitrarily.
  • One Level of typically about 100 kV DC voltage coincides with the illustrated abscissa.
  • the illustrated pulse voltage is thus superimposed on the DC voltage.
  • the pulses 66 and 67 have a pulse width 62 of less than 1 microseconds, wherein the individual pulses 66, 67 have a steeply rising edge with a rise time 64 and a less steeply sloping edge.
  • the pulse repetition time is typically between 10 ⁇ s and 100 ms.
  • the individual pulses 66, 67 have such a total amplitude that, beyond the predetermined DC voltage, a predetermined energy density is achieved.
  • the pulse rise time 64 is short compared to the pulse fall time.
  • FIG. 4 to FIG. 9 show examples of electrode systems for generating corona discharges in preferably aqueous media.
  • a plate-and-plate arrangement of a first plate 70a as an electrode and a second plate 70b as an electrode is illustrated.
  • the first plate 70a and the second plate 70b are arranged parallel to each other.
  • the first plate 70a forms the high voltage electrode and is connected to the high voltage pulse generator 46 via a high voltage cable.
  • the second plate 70b forms the counter electrode and is connected as a grounded electrode to the high voltage pulse generator 46 in connection.
  • FIG. 5 A corresponding arrangement with specially flat plate electrodes is in FIG. 5 shown. Again there are two solid plate electrodes 70a and 70c at a fixed distance with a high voltage electrode 71 in the middle. In this plate-wire plate assembly, the high voltage electrode 71 is made as a solid wire and connected to the high voltage output of the high voltage pulse generator 46 connected. The grounded plates 70a, 70c are also in communication with the high voltage pulse generator.
  • FIG. 6 shows a wire-tube arrangement as an electrode system.
  • a high-voltage electrode 71 projects centrally into a cylindrical electrode 72.
  • the high voltage electrode 71 is made as a solid wire and connected to the high voltage pulse generator 46.
  • the cylindrical electrode 72 which is preferably configured as a wire mesh, is grounded and communicates with the high voltage pulse generator 46.
  • FIG. 7 shows a tip-plate assembly as an electrode system.
  • Three tips 73 are connected to the high voltage pulse generator 46 via a high voltage line.
  • the tips 73 are arranged at right angles to a grounded plate electrode 74.
  • the distance of the tip electrodes 73 to the plate electrode 74 is adjustable and thus can be adapted for different process conditions.
  • FIG. 8 shows an electrode system assembly comprising 3 plates 70a, 70d and 70e.
  • the first plate 70a which is connected as a high-voltage electrode to the high-voltage pulse generator 46, is arranged centrally between two solid plates 70d and 70e.
  • the plates 70a and 70b are connected via a plate connector 70f. Since the plate 70d as a grounded counter electrode is in communication with the high voltage pulse generator 46, the plate 70e above the plate connector 70f also functions as a grounded counter electrode.
  • FIG. 9 shows an electrode system as a grid-grid arrangement. Analogous to FIG. 4 Here, a first grid 75a and a second grid 75b are parallel to each other.
  • the first grid 75a forms the high voltage electrode and is connected to the high voltage pulse generator 46.
  • the second grid 75b forms the grounded counter electrode and communicates with the high voltage pulse generator 46.
  • a hybrid discharge wherein an electrode 75a is located entirely outside a fiber suspension 39 to be treated and a second electrode 75b is wholly or partially immersed in the fiber suspension 39 is provided with an alternative arrangement in which the screen is configured as electrode 75a is generated.
  • the screen is designed as a grid electrode and forms the high voltage electrode which is connected to the high voltage pulse generator 46.
  • the grounded counter electrode 76 b is designed as a grid electrode and is in communication with the high voltage pulse generator 46.
  • a high-voltage electrode comprising a plurality of electrically connected rod electrodes is arranged in the near-surface gas space of the fiber suspension 39 or the paper such that their rods are parallel to the surface.
  • a grounded counter electrode is designed as a solid plate and arranged in distributed over the entire surface equidistant distances from the high voltage electrode.
  • FIG. 10 is that out FIG. 1 known schematic press apparatus 11 enlarged and shown in more detail.
  • the paper 27 is guided over numerous transport rollers and rollers through the press device 11 and thereby increasingly dewatered and compacted.
  • the electrodes 47 and 48 which form a plasma reactor within the press apparatus 11, are arranged.
  • the electrodes 47 and 48 are connected to the high voltage pulse generator 46.
  • a plasma is generated between the electrodes 47, 48 as already described above.
  • the paper web 27 extends between the electrodes 47,48 and is treated on both sides with plasma.
  • the paper web 27 forms a dielectric barrier already described and can thus favor the streamer formation.
  • the electrode 12a is configured as a roller electrode, similar to the roller electrode in FIG FIG. 11 ,
  • the paper 27 is guided by the roller electrode 12a.
  • a plasma for the treatment of the paper 27 is generated by means of the high-voltage generator 46 connected to them.
  • the transport roller 12 represents the grounded counterelectrode 12a.
  • the paper 27 is guided by the transport roller 12 in a force-fit and form-locking manner.
  • a likewise grounded counter electrode 12c which follows the course of the transport roller 12 in a semicircular manner, is electrically connected in a manner not shown to the transport roller 12, in particular to the roller electrode 12a. It is formed with a constant distance thus an electrode assembly in which the individual wires are arranged centrally 12b to 12b n.
  • the paper 27 to be processed thus passes over the transport roller 12 via the grounded electrode 12a and is thus subjected to plasma and / or gas discharges by the wires 12b to 12b n arranged between the two electrodes 12a and 12c.
  • the arrangement is also referred to as a curved wire-plate arrangement which forms a plasma reactor.

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Abstract

Disclosed is a device for guiding and/or deflecting and/or pressing and/or reeling and/or refining a processing material during the production of paper (27), paperboard, or cardboard or during a treatment modifying the properties thereof. Said device comprises a roll (12) that enters in contact with the processing material. The inventive device is equipped with a roll (12) that is embodied as a first electrode (12a) while a second electrode (12b) is arranged such that the electrodes (12,12b) are placed on opposite sides of the processing material, whereby a plasma can be generated in the processing material or in the immediate vicinity thereof. The treatment of the processing material or the paper (27) with plasma makes it possible to improve the tensile strength and the quality features of the paper (27).

Description

Die Erfindung betrifft eine Vorrichtung zum Führen und/oder Umlenken und/oder Pressen und/oder Aufrollen und/oder Veredeln eines Prozessgutes bei der Herstellung von Papier, Pappe oder Karton oder bei einer deren Eigenschaften verändernden Behandlung.The invention relates to a device for guiding and / or deflecting and / or pressing and / or rolling up and / or finishing a process material in the production of paper, paperboard or cardboard or in a treatment whose properties change treatment.

Die Erfindung betrifft auch eine Vorrichtung zum Führen und/oder Umlenken und/oder Pressen und/oder Aufrollen und/oder Veredeln eines Prozessgutes bei der Herstellung von Papier, Pappe oder Karton oder bei einer deren Eigenschaften verändernde Behandlung, umfassend eine mit dem Prozessgut in Kontakt kommende Walze.The invention also relates to a device for guiding and / or diverting and / or pressing and / or rolling up and / or finishing a process material in the production of paper, paperboard or cardboard or in the case of a property-altering treatment comprising one in contact with the process material coming roll.

Des weiteren betrifft die Erfindung ein Verfahren zur Herstellung oder Behandlung eines Prozessgutes bei der Herstellung oder Behandlung von Papier, Karton oder Pappe, vorzugsweise zum Betrieb einer Vorrichtung nach der Erfindung, wobei das Prozessgut mit vorzugsweise nicht thermischen, großflächigem Plasma unter Atmosphärendruck in Kontakt gebracht, das Plasma in unmittelbarer Nähe zum Prozessgut erzeugt oder in dem Prozessgut oder in seiner unmittelbaren Umgebung eine Gasentladung, insbesondere eine Koronaentladung, unter Atmosphärendruck erzeugt wird.Furthermore, the invention relates to a method for producing or treating a process material in the production or treatment of paper, cardboard or cardboard, preferably for operating a device according to the invention, wherein the process material is brought into contact with preferably non-thermal, large-area plasma under atmospheric pressure, the plasma is generated in the immediate vicinity of the process material or in the process material or in its immediate vicinity, a gas discharge, in particular a corona discharge, is generated under atmospheric pressure.

Die Anmelderin hat sich unter Bezugnahme auf die ältere Anmeldung mit der Veröffentlichungsnummer DE 103 59 847 A1 freiwillig eingeschränkt und gesonderte Patentansprüche für Deutschland (DE) vorgelegt.The Applicant has referred to the prior application with the publication number DE 103 59 847 A1 voluntarily restricted and separate claims for Germany (DE) submitted.

In einer Papierherstellungsanlage oder in Teilen einer Papierherstellungsanlage verlässt ein in der Regel noch feuchtes Papier, Pappe oder Karton einen Siebbereich der Papierherstellungsanlage und gelangt von dort in einen Pressenbe reich der Papierherstellungsanlage. Im Pressenbereich wird das Papier, Pappe oder Karton entwässert.In a paper manufacturing plant or in parts of a papermaking plant leaves a usually still wet paper, cardboard or cardboard a screen area of the papermaking plant and from there into a Pressenbe rich of paper making plant. In the press area, the paper, cardboard or cardboard is drained.

An den Pressenbereich schließt sich ein Bereich der Veredelung für das Papier an. Die Veredelung erfolgt entweder integriert in die Papierherstellungsanlage oder auf einer separaten Anlage. Die Veredelung von Papier erfolgt häufig in mehreren aufeinander folgenden Verfahrensschritten. Folgende Qualitätseigenschaften sollen durch die Veredelung positiv beeinflusst werden:

  • Optische Eigenschaften, wie Glätte, Glanz, Weiße, Gleichmäßigkeit und Kontrast eines Druckergebnisses,
  • Verbesserung der Bedruckbarkeit für moderne Druckverfahren,
  • Erhöhung der Papierfestigkeit und einer Rupffestigkeit,
  • Erhöhung einer Dimensionsstabilität des Papiers,
  • Erhöhung einer Unempfindlichkeit gegen beispielsweise Feuchte,
  • Erhöhung einer Recyclingfähigkeit des Papiers.
The press area is followed by an area of finishing for the paper. The finishing takes place either integrated in the papermaking plant or on a separate one Investment. The finishing of paper often takes place in several successive process steps. The following quality properties should be positively influenced by the refinement:
  • Optical properties, such as smoothness, gloss, whiteness, uniformity and contrast of a printed result,
  • Improvement of printability for modern printing processes,
  • Increase the paper strength and a pick resistance,
  • Increasing a dimensional stability of the paper,
  • Increasing insensitivity to, for example, moisture,
  • Increase the recyclability of the paper.

Vorzugsweise erfolgt nach der Behandlung des Papiers eine oberflächenschonende Trocknung des Papiers, z.B. Infrarottrocknung und/oder Lufttrocknung. Bei Textilien und/oder Kunststoffen ist eine Behandlung zur Verbesserung der Oberflächenqualität mit nichtthermischen, "kalten Plasmen" bereits bekannt. Die bisherigen Verfahren verwenden hierzu Niederdruck-Plasmareaktoren, welche wegen der notwendigen Vakuumerzeugung technisch sehr aufwendig sind. Atmosphärendruckverfahren, wie sie in der Papierindustrie zur Beherrschung der heute üblichen Prozessgeschwindigkeiten nötig sind, sind bisher nicht bekannt.Preferably, after the paper is treated, a surface-friendly drying of the paper, e.g. Infrared drying and / or air drying. For textiles and / or plastics, a treatment for improving the surface quality with non-thermal, "cold plasmas" is already known. The previous methods use this low-pressure plasma reactors, which are technically very complicated because of the necessary vacuum generation. Atmospheric printing processes, as they are needed in the paper industry to master the usual process speeds today, are not yet known.

Aus WO 2004/101891 A1 ist ein Verfahren zur Behandlung von Papier nach abgeschlossener Blattbildung mit Plasma bekannt.Out WO 2004/101891 A1 For example, a method of treating paper after completed sheet formation with plasma is known.

Aus DE 19 836 669 A1 ist ein Verfahren zur Oberflächenvorbehandlung am festen Papier nach abgeschlossener Blattbildung bekannt.Out DE 19 836 669 A1 For example, a method of surface pretreatment on solid paper after completed sheet formation is known.

Aus EP 1 067 433 A1 ist es bekannt, zur Erzeugung des Plasmas zwischen den Elektroden eine oszillierende Hochspannung zu nutzen, wobei mittels eines Wechselspannungsgenerators ein kontinuierliches Hochspannungsfeld erzeugt wird.Out EP 1 067 433 A1 It is known to use an oscillating high voltage to generate the plasma between the electrodes, wherein a continuous high voltage field is generated by means of an AC voltage generator.

Der Erfindung liegt die Aufgabe zugrunde, eine Vorrichtung und ein Verfahren zur Verfügung zu stellen, um die Papierqualität bei der Papierherstellung weiter zu steigern.The invention has for its object to provide an apparatus and a method available to further increase the paper quality in papermaking.

Die vorrichtungsbezogene Aufgabe wird gelöst durch mindestens zwei Elektroden zur Erzeugung eines Plasmas in dem Prozessgut oder in seiner unmittelbaren Umgebung, wobei die beiden Elektroden aufeinander gegenüberliegenden Seiten des Prozessgutes angeordnet sind.The device-related object is achieved by at least two electrodes for generating a plasma in the process material or in its immediate surroundings, wherein the two electrodes are arranged on mutually opposite sides of the process material.

Des Weiteren wird die Aufgabe durch die eingangs genannte zweite Vorrichtung dadurch gelöst, dass die Walze als eine erste Elektrode hergerichtet ist, wobei in dem Prozessgut oder in seiner unmittelbaren Umgebung ein Plasma erzeugbar ist. Dabei ist eine zweite Elektrode derart relativ zur Walze angeordnet, dass das Prozessgut zwischen der Walze, insbesondere der ersten Elektrode, und der zweiten Elektrode transportier- bzw. führbar ist. Mit dieser Art der Anordnung kann auf vorteilhafte Weise das Papier oder Prozessgut zwischen der Walze, welche als erste Elektrode hergerichtet ist, und der zweiten Elektrode mit Plasma behandelt werden.Furthermore, the object is achieved by the second device mentioned above in that the roller is prepared as a first electrode, wherein in the process material or in its immediate vicinity, a plasma can be generated. In this case, a second electrode is arranged relative to the roller such that the process material can be transported or guided between the roller, in particular the first electrode, and the second electrode. With this type of arrangement, the paper or process material between the roller, which is prepared as a first electrode, and the second electrode can be treated with plasma in an advantageous manner.

Durch die Behandlung des vorzugsweise unbehandelten Papiers wird die molekulare Struktur der Papieroberfläche verändert. Dadurch können folgende vorteilhafte Effekte erzielt werden:

  • Beseitigung von "farbigen Molekülgruppen" an der Oberfläche des Papiers und damit eine Aufhellung des Papiers,
  • Erhöhung einer Absorptionsfähigkeit für Druckfarben des Papiers,
  • Erhöhung der Festigkeit des Papiers.
The treatment of the preferably untreated paper alters the molecular structure of the paper surface. As a result, the following advantageous effects can be achieved:
  • Elimination of "colored molecule groups" on the surface of the paper and thus a whitening of the paper,
  • Increasing an ink absorbing capacity of the paper,
  • Increasing the strength of the paper.

In einer bevorzugten Ausführungsform der Erfindung ist die Walze derart angeordnet, dass sie mit dem Prozessgut, vorzugsweise einem gebildeten Blatt, vorzugsweise einem gepressten Blatt, insbesondere einer Papierbahn, in Kontakt kommt. Dadurch dass die Walze in der erfindungsgemäßen Vorrichtung als eine Elektrode ausgestaltet ist, kann das über ihr laufende Prozessgut mit Plasma behandelt werden. Auch bereits bestehende ältere Veredelungsanlagen können so mit Vorteil durch Austausch der erfindungsgemäßen Vorrichtung gegen die herkömmlichen Transportwalzen, hochgerüstet werden, und somit das Papier mit einer erhöhten Qualität bereitstellen.In a preferred embodiment of the invention, the roller is arranged such that it comes into contact with the process material, preferably a formed sheet, preferably a pressed sheet, in particular a paper web. The fact that the roller is designed as an electrode in the device according to the invention, the running over her Process material to be treated with plasma. Even existing older refining plants can be beneficial be upgraded by replacing the device according to the invention against the conventional transport rollers, and thus provide the paper with an increased quality.

Zweckmäßig ist dabei eine zweite Walze, wobei die zweite Walze derart relativ zur Walze angeordnet ist, dass ein flächiges Prozessgut, insbesondere die Papierbahn, beidseitig mit den Walzen in Kontakt kommt. Wird das Papier mittels diverser Transportwalzen quasi slalomartig durch eine Veredelungsmaschine geführt, ist es im Sinne einer effektiven Behandlung von Vorteil, die als Elektroden ausgestalteten Walzen derart hintereinander anzuordnen, dass das Papier zeitlich nacheinander von beiden Seiten effektiv mit Plasma behandelt werden kann.In this case, a second roller is expedient, wherein the second roller is arranged relative to the roller in such a way that a flat process material, in particular the paper web, comes into contact with the rollers on both sides. If the paper is guided quasi slalom-like by means of various transport rollers through a finishing machine, it is in terms of effective treatment of advantage to arrange the electrodes configured as electrodes one behind the other, that the paper can be treated successively in time from both sides with plasma.

In den Unteransprüchen 6 bis 8 sind für eine Veredelungsanlage, eine Trocknungsanlage und eine Pressenanlage für Papier, Pappe oder Karton besondere Ausführungsvarianten oder optionale Einsatzgebiete genannt.In the dependent claims 6 to 8 special variants or optional applications are called for a finishing plant, a drying plant and a press line for paper, cardboard or cardboard.

Zweckmäßig ist ferner, dass die Walze mit einer gasdurchlässigen Oberfläche hergerichtet ist.It is also expedient that the roller is prepared with a gas-permeable surface.

Ein weiteres bevorzugtes Ausgestaltungsmerkmal ist, dass die Walze zum radialen Zuführen eines Gasstromes hergerichtet ist. Durch diese vorteilhafte Anordnung werden, vorzugsweise fein verteilte Luftblasen oder Sauerstoff oder Sauerstoff mit einem Trägergas wie z.B. Argon, in die Walze eingeströmt, die dann wiederum durch die gasdurchlässige Oberfläche in das Papier eindringen können. Mit Hilfe der eingeströmten Gase und der gleichzeitigen Behandlung mit Plasma werden die späteren Qualitätseigenschaften wesentlich erhöht.Another preferred design feature is that the roll is adapted to radially supply a gas stream. By virtue of this advantageous arrangement, preferably finely divided air bubbles or oxygen or oxygen are mixed with a carrier gas, e.g. Argon, flowed into the roller, which in turn can penetrate through the gas-permeable surface in the paper. With the help of the infused gases and the simultaneous treatment with plasma, the later quality properties are substantially increased.

Weiterhin kann die Vorrichtung mit einem Mittel zum Anströmen des Prozessgutes mit einem Gasstrom ausgestaltet sein. Der Gasstrom wird unter Ausnutzung der bereits genannten Vorteile direkt in den Behandlungsraum, also zwischen die beiden Elektroden geleitet.Furthermore, the device can be configured with a means for flowing the process material with a gas stream. Taking advantage of the advantages already mentioned, the gas stream is conducted directly into the treatment space, ie between the two electrodes.

Die genannten Elektroden bzw. Walzen erzeugen das Plasma auf besonders vorteilhafte Weise durch einen Hochspannungsimpulsgenerator, der mit der bzw. den Elektroden verbunden ist. Das Plasma oder eine gepulste Koronaentladung direkt oberhalb und/oder unterhalb des Papiers kann unter Benutzung extrem kurzer Hochspannungsimpulse von weniges als 10 µs, insbesondere 1 µs, und besonders vorteilhaft deutlich geringer als 1 µs mit Spannungen von einigen kV bis über 100 kV, abhängig vom Abstand der Elektroden und der Eigenschaften des Papiers auf vorteilhafte Weise erzeugt werden.The said electrodes or rollers generate the plasma in a particularly advantageous manner by means of a high-voltage pulse generator which is connected to the electrode (s). The plasma or a pulsed corona discharge directly above and / or below the paper, using extremely short high voltage pulses of less than 10 microseconds, in particular 1 microseconds, and particularly advantageously significantly less than 1 microseconds with voltages of a few kV to over 100 kV, depending on Distance of the electrodes and the properties of the paper can be produced in an advantageous manner.

Nach der verfahrensseitigen Maßgabe der Erfindung ist vorgesehen, dass das Prozessgut beidseitig mit dem Plasma in Kontakt gebracht bzw. beidseitig mittels der Gasentladung behandelt wird. Hierbei ist es von besonderem Vorteil, dass bei einer gleichzeitigen oder annähernd gleichzeitigen beidseitigen Behandlung des Prozessgutes mit Plasma bzw. einer Gasentladung, welche unter anderem eine oberflächenverändernde Wirkung hat oder in die Molekularstruktur des Prozessgutes eingreift, dass das Prozessgut homogen verändert wird. Das bedeutet, dass eventuell auftretende Inhomogenitäten bzw. Spannungszustände im Prozessgut vermieden werden. Des Weiteren ist es besonders vorteilhaft, dass bei dieser Art der Behandlung das Prozessgut gleichzeitig teilweise als dielektrische Barriere fungiert, wodurch sich ein Übergang von einem Streamer zu einem Durchschlag besser unterdrücken lässt.According to the method side of the invention, it is provided that the process material is brought into contact with the plasma on both sides or treated on both sides by means of the gas discharge. In this case, it is of particular advantage that with a simultaneous or approximately simultaneous two-sided treatment of the process material with plasma or a gas discharge which inter alia has a surface-altering effect or intervenes in the molecular structure of the process material that the process material is changed homogeneously. This means that possibly occurring inhomogeneities or stress states in the process material are avoided. Furthermore, it is particularly advantageous that in this type of treatment, the process material at the same time partially acts as a dielectric barrier, which can better suppress a transition from a streamer to a breakdown.

Vorzugsweise wird als Prozessgut ein noch ungepresstes und/oder feuchtes Blatt oder trockenes Blatt in einem Papier- oder Kartonherstellungsprozess verwendet.Preferably, a still unpressed and / or moist sheet or dry sheet is used in a paper or board production process as process material.

Weitere bevorzugte Verfahrensmerkmale sind durch die Patentansprüche 15 bis 41 beschrieben. Diesen liegen unter anderem folgende Überlegungen zugrunde:Further preferred method features are described by the claims 15 to 41. These are based inter alia on the following considerations:

Zur Erzeugung des Plasmas bzw. der Gasentladung zwischen Elektroden werden vorzugsweise Hochspannungsimpulse mit einer Dauer von weniger als 10 µs erzeugt. Insbesondere hat sich die Verwendung von derartig kurzen Hochspannungsimpulsen als besonders vorteilhaft gezeigt, wogegen die Verwendung von Radiofrequenz-(RF-) oder Mikrowellenimpulsen oder von Hochspannungseinzelimpulsen mit mehr als 10 µs Dauer, wie in WO 2004/101891 A1 beschrieben, weit weniger effizient ist.To generate the plasma or the gas discharge between electrodes, high-voltage pulses with a duration of less than 10 μs are preferably generated. In particular, has become the use of such short high voltage pulses has been shown to be particularly advantageous, whereas the use of radio frequency (RF) or microwave pulses or high voltage single pulses of more than 10 μs in duration, as in US Pat WO 2004/101891 A1 described, is far less efficient.

Bei der Behandlung der Papieroberfläche mit kaltem Plasma werden bestimmte Radikale erzeugt (OH-,HOO,O3), welche mit der Papieroberfläche chemisch reagieren. Radikale können unter anderem auch bleichende chemische Reaktionen auslösen, insbesondere freier Sauerstoff O, insbesondere auch ein Hydroxyl-Radikal OH, insbesondere Ozon O3, als auch freie funktionelle Gruppen wie z.B. OH-Gruppen, COOH-Gruppen. Diese funktionalen Gruppen sind maßgeblich daran beteiligt, insbesondere die Bindungsfestigkeit der Fasern untereinander zu erhöhen, wodurch sich eine Reißfestigkeit des Papiers und damit eine mögliche Verarbeitungsgeschwindigkeit erhöht. Des Weiteren haben die funktionalen Gruppen die Eigenschaft, die Bindung zu Farbstoffen und die Benetzbarkeit von Papier zu erhöhen, wodurch sich die spätere Bedruckbarkeit des Papiers gezielt steuern und verbessern lässt.In the treatment of the paper surface with cold plasma certain radicals are generated (OH - , HOO, O 3 ), which react chemically with the paper surface. Radicals may, inter alia, also trigger bleaching chemical reactions, in particular free oxygen O, in particular also a hydroxyl radical OH, in particular ozone O 3 , as well as free functional groups such as OH groups, COOH groups. These functional groups are significantly involved, in particular to increase the bond strength of the fibers with each other, which increases a tear strength of the paper and thus a possible processing speed. Furthermore, the functional groups have the property to increase the binding to dyes and the wettability of paper, which can be targeted control and improve the subsequent printability of the paper.

Radikale werden in Gasentladungen dadurch erzeugt, dass energiereiche Elektronen mit Molekülen zusammenstoßen und diese dadurch disoziieren oder anregen und so zur radikalen Bildung führen. Bei der Dissoziation werden unmittelbar Radikale freigesetzt, während bei der Anregung durch anschließende strahlende Übergänge UV-Licht erzeugt wird, welches wiederum mit vorzugsweise Luft- und Wassermolekülen reagiert und diese disoziiert. Um ausreichend energiereiche Elektronen im Bereich von ca. 5 eV (Elektronenvolt) bis größer 15 eV zu erhalten, werden extrem hohe elektrische Felder benötigt. Diese hohen Feldstärken treten insbesondere am Kopf von sogenannten Streamern auf. Streamer sind Entladungskanäle, die sich im Aufbau befinden und sich aufgrund der angelegten hohen externen Feldstärken ausbilden. Ein Aufbau solcher Streamer findet innerhalb weniger 10 ns statt und geht dann schnell in einen thermischen Durchschlagskanal über. Da in einem thermischen Durchschlagskanal keine energiereichen Elektronen gebildet werden, ist es unter anderem das Ziel, diese thermischen Durchschläge zu vermeiden oder auf ein Minimum zu reduzieren. Um eine gute Energieeffizienz der Erzeugung von vorzugsweise Radikalen in Gasen zu erhalten, ist es daher erforderlich, mit den bereits erwähnten kurzen Hochspannungseinzelimpulsen zu arbeiten. Vorzugsweise ist die Pulsdauer deutlich kürzer als es eine Aufbauzeit eines vollständigen Durchschlages im jeweiligen Medium entspricht.Radicals are generated in gas discharges by high-energy electrons collide with molecules and thereby dissociate or excite them and thus lead to radical formation. In the dissociation, radicals are released immediately, while the excitation by subsequent radiant transitions UV light is generated, which in turn reacts with and preferably dissociates air and water molecules. To obtain sufficiently high-energy electrons in the range of about 5 eV (electron volts) to greater than 15 eV, extremely high electric fields are required. These high field strengths occur in particular at the head of so-called streamers. Streamer are discharge channels that are under construction and form due to the applied high external field strengths. An assembly of such streamer takes place within less than 10 ns and then rapidly merges into a thermal breakdown channel. As in a thermal It is one of the objectives of the breakdown channel to avoid the formation of high-energy electrons, or to minimize or minimize these thermal breakdowns. In order to obtain a good energy efficiency of the generation of preferably radicals in gases, it is therefore necessary to work with the short high voltage single pulses already mentioned. Preferably, the pulse duration is significantly shorter than corresponds to a build-up time of a complete breakdown in the respective medium.

Befindet sich die Papierbahn oder das Prozessgut zwischen den zur Streamerentladung benutzten Elektroden, so ist dies besonders vorteilhaft, da das Papier oder das Prozessgut dadurch teilweise als eine dielektrische Barriere wirkt. Durch die dielektrische Barriere lässt sich der Übergang vom Streamer zum Durchschlag besser kontrollieren.If the paper web or the process material is located between the electrodes used for the streamer discharge, this is particularly advantageous because the paper or the process material thereby partially acts as a dielectric barrier. The dielectric barrier makes it easier to control the transition from the streamer to the breakdown.

Bevorzugte, jedoch keinesfalls einschränkende Ausführungsbeispiele der Erfindung werden nunmehr anhand der Zeichnung näher erläutert. Zur Verdeutlichung ist die Zeichnung nicht maßstäblich ausgeführt, und gewisse Merkmale sind nur schematisiert dargestellt. Einander entsprechende Teile sind in den Figuren mit denselben Bezugszeichen versehen. Im Einzelnen zeigt die

FIG 1
eine schematische Darstellung einer Papierherstel- lungsanlage mit einer Siebvorrichtung, einer Pressen- vorrichtung nach der Erfindung und einer Veredelungs- und/oder Trockenanlage,
FIG 2
eine Darstellung (Schnitt) einer Anordnung zur Erzeu- gung von Radikalen in Koronaplasmen in Pulpe oder Luft: Parallelplatten- oder Rohranordnung mit Draht, dem eine gepulste Hochspannung überlagert wird,
FIG 3
eine Prinzipdarstellung von Impulsen zur Erzeugung von Radikalen in Koronaentladungen in Luft oder wässrigen Medien bei Einsatz kurzes (typisch kleiner 1 µs) Hoch- spannungsimpulse mit hoher Impulswiederholrate,
FIG 4 bis 9
Elektrodenanordnungen und Elektrodensysteme zur Erzeugung von Koronaentladungen: Platte-Platte, Plat- te-Draht-Platte, koaxiale Draht-Rohr-, Spitze-Platte-, Mehrfachspitzen-Platte-, Gitter-Platte (Rohr-, Gitter- Gitter-Anordnungen,
FIG 10
eine Veredelungsanlage mit der erfindungsgemäßen Vor- richtung, und
FIG 11
eine erfindungsgemäße Vorrichtung mit einer Walze als Transportrolle.
Preferred, but by no means limiting embodiments of the invention will now be explained in more detail with reference to the drawing. For clarity, the drawing is not drawn to scale, and certain features are shown only schematically. Corresponding parts are provided in the figures with the same reference numerals. In detail, the shows
FIG. 1
1 is a schematic representation of a papermaking plant with a screening device, a press device according to the invention and a finishing and / or drying plant;
FIG. 2
a representation (section) of an arrangement for the generation of radicals in corona plasmas in pulp or air: parallel plate or tube arrangement with wire, which is overlaid with a pulsed high voltage,
FIG. 3
a schematic representation of pulses for generating radicals in corona discharges in air or aqueous media when using short (typically less than 1 μs) high-voltage pulses with high pulse repetition rate,
4 to 9
Electrode arrangements and electrode systems for generating corona discharges: plate-plate, plate-wire plate, coaxial wire-tube, tip-plate, multi-tip plate, grid plate (tube, grid-grid arrangements,
FIG. 10
a processing plant with the device according to the invention, and
FIG. 11
a device according to the invention with a roller as a transport roller.

FIG 1 zeigt eine schematische Darstellung einer Papierherstellungsanlage 1, wie sie in heutigen Papierfabriken eingesetzt wird. Ihre Konstruktion und die Kombination unterschiedlicher Aggregate werden von der Art der zu erzeugenden Papier-, Karton- und Pappesorten sowie der eingesetzten Rohstoffe bestimmt. Die Papierherstellungsanlage 1 hat eine räumliche Ausdehnung von ungefähr 10 m in der Breite und ungefähr 120 m in der Länge. Es dauert nur wenige Sekunden vom ersten Auftreffen einer Faser-Suspension oder einer Pulpe 39 auf eine Siebvorrichtung 9 bis zum fertigen Papier 27, welches letztendlich in einer Aufrollung 15 aufgerollt wird. Der gesamte Papierherstellungsprozess unterteilt sich dabei im Wesentlichen in die Bereiche Stoffaufbereitung, Papiermaschine, Veredelung und Ausrüstung. FIG. 1 shows a schematic representation of a papermaking plant 1, as used in today's paper mills. Their construction and the combination of different aggregates are determined by the type of paper, board and paperboard types to be produced, as well as the raw materials used. The papermaking plant 1 has a spatial extent of about 10 m in width and about 120 m in length. It takes only a few seconds from the first impact of a fiber suspension or pulp 39 on a screening device 9 to the finished paper 27, which is finally rolled up in a reel 15. The entire papermaking process is essentially subdivided into the areas of stock preparation, paper machine, finishing and equipment.

Ein Stoffauflauf 7 der Papierherstellungsanlage 1 verteilt die Faserstoff-Suspension gleichmäßig über die gesamte Siebbreite. Am Ende der Siebvorrichtung 9 enthält die Papierbahn 27 noch immer ca. 80 % Wasser.A headbox 7 of the papermaking plant 1 distributes the pulp suspension uniformly over the entire wire width. At the end of the screening device 9, the paper web 27 still contains about 80% water.

Ein weiterer Entwässerungsprozess erfolgt durch mechanischen Druck in der Pressenvorrichtung 11. Dabei wird die Papierbahn 27 zwischen Walzen aus Stahl hindurchgeführt und dadurch entwässert. An die Pressenvorrichtung 11 schließt sich eine Trocknungsanlage 13 an. Das verbleibende Restwasser wird in der Trocknungsanlage 13 verdampft. Slalomartig durchläuft die Papierbahn 27 mehrere dampfbeheizte Trockenzylinder. Am Ende hat das Papier 27 eine Restfeuchte von wenigen Prozent. Der in der Trocknungsanlage 13 entstandene Wasserdampf wird abgesaugt und in eine nicht dargestellte Wärmerückgewinnungsanlage geführt.Another dewatering process is carried out by mechanical pressure in the press device 11. In this case, the paper web 27 is passed between rollers made of steel and thereby dewatered. The press device 11 is followed by a drying system 13. The remaining residual water is evaporated in the drying plant 13. Slalom-like, the paper web 27 passes through several steam-heated drying cylinders. In the end, the paper 27 has a residual moisture of a few percent. Of the in the drying plant 13 resulting water vapor is sucked off and passed into a heat recovery system, not shown.

Für eine Behandlung der Papierbahn 27 nach der erfindungsgemäßen Vorrichtung sind in der Pressenvorrichtung 11 eine erste Elektrode 47 und eine zweite Elektrode 48 derart angeordnet, dass die Papierbahn mittels einer Transportrolle 12 zwischen den beiden Elektroden 47, 48 geführt wird und zeitgleich mit Plasma behandelt wird. Damit zur Behandlung der Papierbahn 27 ein großflächiges Plasma unter Atmosphärendruck in der unmittelbaren Nähe der Papierbahn 27 erzeugt werden kann, sind die Elektroden 47 und 48 mit einem Hochspannungsimpulsgenerator 46 verbunden. Mit Hilfe dieses Hochspannungsimpulsgenerators 46 wird zwischen den Elektroden 47 und 48 ein großvolumiges Plasma mit einem großen Querschnitt und mit einer hohen Leistungsdichte erzeugt. Hierbei ist eine Plasmadichte homogen über den Behandlungsbereich, welcher durch die Elektroden 47 und 48 abgedeckt wird, verteilt. Das großvolumige Plasma mit hoher Leistungsdichte wird mittels der erfindungsgemäßen Anordnung dadurch erzeugt, dass einer DC-Korona-Entladung intensive, kurz andauernde Hochspannungsimpulse mit einer hohen Impulswiederholrate von 1 kH überlagert werden. Bei dieser Betriebsweise wird ein äußerst homogenes, großvolumiges Plasma mit einer hohen Leistungsdichte erzeugt, ohne dass es zu den bei DC-Korona-Entladungen bekannten Plasmaeinschnürungen kommt.For a treatment of the paper web 27 according to the device according to the invention, a first electrode 47 and a second electrode 48 are arranged in the press apparatus 11 such that the paper web is guided by means of a transport roller 12 between the two electrodes 47, 48 and treated simultaneously with plasma. In order that a large-area plasma under atmospheric pressure in the immediate vicinity of the paper web 27 can be produced for the treatment of the paper web 27, the electrodes 47 and 48 are connected to a high-voltage pulse generator 46. By means of this high-voltage pulse generator 46, a large-volume plasma with a large cross section and with a high power density is generated between the electrodes 47 and 48. Here, a plasma density is homogeneously distributed over the treatment area which is covered by the electrodes 47 and 48. The large-volume plasma with high power density is generated by means of the inventive arrangement in that a DC corona discharge intensive, short-lasting high voltage pulses are superimposed with a high pulse repetition rate of 1 kH. In this mode of operation, a very homogeneous, large-volume plasma with a high power density is produced without the plasma constrictions that are known in DC corona discharges.

Um die Behandlungswirkung, welche das kalte großflächige Plasma auf die Papierbahn 27 ausübt zu unterstützen wird mittels eines Gasverteilers 81 über eine Gasleitung 80 Sauerstoff mit Argon als Trägergas in dem Behandlungsraum zwischen die Elektroden 47 und 48 eingeleitet. Mit Hilfe des Sauerstoff-Argon-Gemisches werden besonders vorteilhaft Hydroxyl-Radikale erzeugt. Hydroxyl-Radikale sind besonders aggressiv und oxidierend, dadurch wird an dem nur wenige Sekunden im Behandlungsbereich zwischen den Elektroden 47 und 48 verweilenden Papierbahn 27 eine Steigerung der Qualitätseigenschaften erzielt.In order to support the treatment effect which the cold large-area plasma exerts on the paper web 27, oxygen is introduced by means of a gas distributor 81 via a gas line 80 with argon as carrier gas into the treatment space between the electrodes 47 and 48. Hydroxyl radicals are particularly advantageously produced with the aid of the oxygen-argon mixture. Hydroxyl radicals are particularly aggressive and oxidizing, thereby lingering only a few seconds in the treatment area between the electrodes 47 and 48 Paper web 27 achieved an increase in quality properties.

Die erste Elektrode 47 in der Pressenvorrichtung 11 ist als eine halbrunde Gitterelektrode ausgeführt. Durch die halbrunde Ausgestaltung der Elektrode 47 kann sie den Papierbahnverlauf über der Transportrolle 12 folgen. Die zweite Elektrode 48 in der Pressenvorrichtung 11 ist als eine Plattenelektrode ausgestaltet und derart angeordnet, dass die Transportrolle 12 zwischen den Elektroden 47 und 48 geführt wird.The first electrode 47 in the press apparatus 11 is designed as a semicircular grid electrode. Due to the semicircular configuration of the electrode 47, it can follow the course of the paper web over the transport roller 12. The second electrode 48 in the press apparatus 11 is configured as a plate electrode and arranged such that the transport roller 12 is guided between the electrodes 47 and 48.

Der Pressvorgang verdichtet das Papiergefüge, die Festigkeit wird nochmals erhöht und eine Oberflächengüte wird entscheidend beeinflusst. Des Weiteren wird durch die Behandlung des gepressten Papiers 27 mit kaltem Plasma, insbesondere mit erzeugten Radikalen, die molekulare Struktur der Papieroberfläche weiter verändert. Neben einer Erhöhung der Festigkeit des Papiers 27 wird eine spätere Bedruckbarkeit verbessert.The pressing process compacts the paper structure, the strength is increased again and a surface quality is decisively influenced. Further, by treating the pressed paper 27 with cold plasma, particularly with generated radicals, the molecular structure of the paper surface is further changed. In addition to increasing the strength of the paper 27, a later printability is improved.

Mit der vorbenannten Elektrodenanordnung 47 und 48 ist es nach der erfindungsgemäßen Vorrichtung und dem erfindungsgemäßen Verfahren möglich, die Papierbahn 27 zwischen vorzugsweise Korona-Plasmen bzw. Streamer-Entladungen zu führen.With the above-mentioned electrode arrangement 47 and 48, it is possible according to the device according to the invention and the method according to the invention to guide the paper web 27 between preferably corona plasmas or streamer discharges.

Ein Streamer ist eine spezielle Form einer sich linear fortbewegenden Plasmawolke oder ein in der Entwicklung befindlicher Entladungskanal, der sich aufgrund der angeregten hohen externen Feldstärke ausbildet. Ein Aufbau solcher Streamer findet innerhalb weniger 10 ns statt und geht sehr schnell in einen thermischen Durchschlagskanal über. Vorbenannte Anordnung des Elektrodensystems, wobei sich die Papierbahn 27 zwischen den zur Streamer-Entladung benutzten Elektroden befindet, ist besonders vorteilhaft, da das Papier 27 dadurch teilweise als eine dielektrische Barriere fungiert, wodurch sich der Übergang vom Streamer zum Durchschlag unterdrücken lässt.A streamer is a special form of a linearly moving plasma cloud or a developing discharge channel that forms due to the excited high external field strength. An assembly of such streamer takes place within less than 10 ns and merges very quickly into a thermal breakdown channel. The aforesaid arrangement of the electrode system, with the paper web 27 between the electrodes used for the streamer discharge, is particularly advantageous, as the paper 27 thereby partially acts as a dielectric barrier, whereby the transition from the streamer to the breakdown can be suppressed.

Durch eine direkte Behandlung der Papierbahn 27 mit dem kalten Plasma werden in der unmittelbaren Umgebung der Papierbahn 27 vorzugsweise die Radikale O3, H2, O2, OH, HO2 und HO2 - erzeugt. Neben einer Festigkeitssteigerung lösen diese Radikale eine bleichende chemische Reaktion aus. Der Hochspannungsimpulsgenerator 46 wird derart betrieben, dass er Spannungsimpulse mit einer Dauer von typisch 1 µs zwischen den Elektroden 47 und 48 erzeugt. Eine für die Erzeugung von Radikalen und Ozon in der Papierbahn und in der unmittelbaren Umgebung der Papierbahn notwendige DC-Spannung liegt bei ca. 10 kV bis einige 100 kV. Die Hochspannungsimpulse werden der DC-Spannung überlagert und bilden so eine Gesamtamplitude von einigen 100 kV. Durch die Behandlung der Papierbahn 27 mit einer kalten elektrischen Entladung, also dem Plasma, werden die Radikale in unmittelbarer Nähe zum Papier oder sogar im Papier 27 erzeugt.By direct treatment of the paper web 27 with the cold plasma 27, preferably the radicals O 3 , H 2 , O 2 , OH, HO 2 and HO 2 - produced in the immediate vicinity of the paper web. In addition to an increase in strength, these radicals trigger a bleaching chemical reaction. The high voltage pulse generator 46 is operated to generate voltage pulses having a duration of typically 1 μs between the electrodes 47 and 48. A necessary for the generation of radicals and ozone in the paper web and in the immediate vicinity of the paper web DC voltage is about 10 kV to some 100 kV. The high voltage pulses are superimposed on the DC voltage to form a total amplitude of a few 100 kV. By treating the paper web 27 with a cold electrical discharge, so the plasma, the radicals are generated in close proximity to the paper or even in the paper 27.

FIG 2 zeigt als weiteres Ausführungsbeispiel eine Schnittdarstellung einer Anordnung zur Erzeugung von Radikalen. In der Mitte der Anordnung ist eine Hochspannungselektrode 50 angeordnet. Der Außenmantel der Anordnung ist als eine Gegenelektrode 51 hergerichtet. In der Anordnung befindet sich eine zu siebende Zellstofffaser-Suspension 39. Zwischen den Elektroden 50 und 51 ist ein Streamer 53 dargestellt. Radikale werden in Streamern dadurch erzeugt, dass energiereiche Elektronen mit Molekülen zusammenstoßen und diese dadurch disoziieren oder anregen. Bei der Dissoziation werden unmittelbar Radikale 59 freigesetzt, während bei der Anregung durch einen anschließenden strahlenden Übergang UV-Licht erzeugt wird. Dieses erzeugte UV-Licht reagiert wiederum mit Wassermolekülen und disoziiert diese. FIG. 2 shows as a further embodiment, a sectional view of an arrangement for generating radicals. In the center of the arrangement, a high voltage electrode 50 is arranged. The outer jacket of the assembly is prepared as a counter electrode 51. The arrangement contains a pulp fiber suspension 39 to be screened. A streamer 53 is shown between the electrodes 50 and 51. Radicals are generated in streamers by the collision of energetic electrons with molecules, thereby disassociating or exciting them. Upon dissociation, radicals 59 are immediately released, while upon excitation by a subsequent radiant transition, UV light is generated. This generated UV light in turn reacts with water molecules and dissociates them.

In FIG 3 ist der applizierte Spannungsverlauf der Hochspannungsimpulse dargestellt. Ein erster Impuls 66 und ein zweiter Impuls 67, mit je einer Impulsbreite 62, weisen einen Abstand von einer Pulswiederholzeit 63 auf. Auf der Abzisse ist die Zeit in Millisekunden und auf der Ordinate die Spannung in kV angegeben. Die Einheiten sind willkürlich gewählt. Ein Niveau von typisch ca. 100 kV der DC-Spannung fällt mit der dargestellten Abzisse zusammen. Die dargestellte Impulsspannung ist also der DC-Spannung überlagert. Die Impulse 66 und 67 weisen eine Pulsbreite 62 von kleiner 1 µs auf, wobei die einzelnen Impulse 66, 67 eine steil ansteigende Flanke mit einer Anstiegszeit 64 und einer weniger steil abfallenden Flanke aufweisen. Die Impulswiederholzeit liegt typischer Weise zwischen 10 µs und 100 ms.In FIG. 3 is the applied voltage waveform of the high voltage pulses shown. A first pulse 66 and a second pulse 67, each having a pulse width 62, have a spacing of one pulse repetition time 63. The abscissa shows the time in milliseconds and the ordinate the voltage in kV. The units are chosen arbitrarily. One Level of typically about 100 kV DC voltage coincides with the illustrated abscissa. The illustrated pulse voltage is thus superimposed on the DC voltage. The pulses 66 and 67 have a pulse width 62 of less than 1 microseconds, wherein the individual pulses 66, 67 have a steeply rising edge with a rise time 64 and a less steeply sloping edge. The pulse repetition time is typically between 10 μs and 100 ms.

Dabei haben die einzelnen Impulse 66, 67 eine solche Gesamtamplitude, das über die vorgegebene Gleichspannung hinaus eine vorgegebene Energiedichte erreicht wird. Wie erwähnt, ist die Pulsanstiegszeit 64 dabei kurz im Vergleich zur Pulsabfallzeit. Durch eine solche Art der Impulse wird erreicht, dass elektrische Durchschläge, die zu räumlichen und zeitlichen Störungen in der homogenen Plasmadichteverteilung führen würden, vermieden werden.In this case, the individual pulses 66, 67 have such a total amplitude that, beyond the predetermined DC voltage, a predetermined energy density is achieved. As mentioned, the pulse rise time 64 is short compared to the pulse fall time. By such a kind of pulses is achieved that electrical breakdowns that would lead to spatial and temporal disturbances in the homogeneous plasma density distribution can be avoided.

FIG 4 bis FIG 9 zeigen Beispiele für Elektrodensysteme zur Erzeugung von Korona-Entladungen in vorzugsweise wässrigen Medien. In FIG 4 ist eine Platte-Platte-Anordnung von einer ersten Platte 70a als Elektrode und einer zweiten Platte 70b als Elektrode dargestellt. Die erste Platte 70a und die zweite Platte 70b sind parallel zu einander angeordnet. Die erste Platte 70a bildet die Hochspannungselektrode und ist über ein Hochspannungskabel mit dem Hochspannungsimpulsgenerator 46 verbunden. Die zweite Platte 70b bildet die Gegenelektrode und steht als geerdete Elektrode mit dem Hochspannungsimpulsgenerator 46 in Verbindung. 4 to FIG. 9 show examples of electrode systems for generating corona discharges in preferably aqueous media. In FIG. 4 For example, a plate-and-plate arrangement of a first plate 70a as an electrode and a second plate 70b as an electrode is illustrated. The first plate 70a and the second plate 70b are arranged parallel to each other. The first plate 70a forms the high voltage electrode and is connected to the high voltage pulse generator 46 via a high voltage cable. The second plate 70b forms the counter electrode and is connected as a grounded electrode to the high voltage pulse generator 46 in connection.

Eine entsprechende Anordnung mit speziell ebenen Plattenelektroden ist in FIG 5 dargestellt. Es sind wiederum zwei massive Plattenelektroden 70a und 70c im festen Abstand vorhanden, wobei mittig eine Hochspannungselektrode 71 verläuft. Bei dieser Platte-Draht-Platte-Anordnung ist die Hochspannungselektrode 71 als massiver Draht ausgeführt und mit dem Hochspannungsausgang des Hochspannungsimpulsgenerators 46 verbunden. Die geerdeten Platten 70a, 70c stehen ebenfalls mit dem Hochspannungsimpulsgenerator in Verbindung.A corresponding arrangement with specially flat plate electrodes is in FIG. 5 shown. Again there are two solid plate electrodes 70a and 70c at a fixed distance with a high voltage electrode 71 in the middle. In this plate-wire plate assembly, the high voltage electrode 71 is made as a solid wire and connected to the high voltage output of the high voltage pulse generator 46 connected. The grounded plates 70a, 70c are also in communication with the high voltage pulse generator.

FIG 6 zeigt eine Draht-Rohr-Anordnung als Elektrodensystem. In eine zylinderförmige Elektrode 72 ragt mittig eine Hochspannungselektrode 71 hinein. Wie in FIG 5 ist die Hochspannungselektrode 71 als massiver Draht ausgeführt und mit dem Hochspannungsimpulsgenerator 46 verbunden. Die zylinderförmige Elektrode 72, welche vorzugsweise als ein Drahtgeflecht ausgestaltet ist, ist geerdet und steht mit dem Hochspannungsimpulsgenerator 46 in Verbindung. FIG. 6 shows a wire-tube arrangement as an electrode system. A high-voltage electrode 71 projects centrally into a cylindrical electrode 72. As in FIG. 5 the high voltage electrode 71 is made as a solid wire and connected to the high voltage pulse generator 46. The cylindrical electrode 72, which is preferably configured as a wire mesh, is grounded and communicates with the high voltage pulse generator 46.

FIG 7 zeigt eine Spitze-Platte-Anordnung als Elektrodensystem. Drei Spitzen 73 sind über eine Hochspannungsleitung mit dem Hochspannungsimpulsgenerator 46 verbunden. Die Spitzen 73 sind rechtwinklig zu einer geerdeten Plattenelektrode 74 angeordnet. Der Abstand der Spitzenelektroden 73 zu der Plattenelektrode 74 ist einstellbar und kann somit für unterschiedliche Prozessbedingungen angepasst werden. FIG. 7 shows a tip-plate assembly as an electrode system. Three tips 73 are connected to the high voltage pulse generator 46 via a high voltage line. The tips 73 are arranged at right angles to a grounded plate electrode 74. The distance of the tip electrodes 73 to the plate electrode 74 is adjustable and thus can be adapted for different process conditions.

FIG 8 zeigt eine Elektrodensystemanordnung, welche 3 Platten 70a, 70d und 70e umfasst. Die erste Platte 70a, welche als Hochspannungselektrode mit dem Hochspannungsimpulsgenerator 46 verbunden ist, ist mittig zwischen zwei massiven Platten 70d und 70e angeordnet. Die Platten 70a und 70b sind über einen Plattenverbinder 70f verbunden. Da die Platte 70d als geerdete Gegenelektrode mit dem Hochspannungsimpulsgenerator 46 in Verbindung steht, hat die Platte 70e über dem Plattenverbinder 70f ebenfalls die Funktion einer geerdeten Gegenelektrode. FIG. 8 shows an electrode system assembly comprising 3 plates 70a, 70d and 70e. The first plate 70a, which is connected as a high-voltage electrode to the high-voltage pulse generator 46, is arranged centrally between two solid plates 70d and 70e. The plates 70a and 70b are connected via a plate connector 70f. Since the plate 70d as a grounded counter electrode is in communication with the high voltage pulse generator 46, the plate 70e above the plate connector 70f also functions as a grounded counter electrode.

FIG 9 zeigt ein Elektrodensystem als Gitter-Gitter-Anordnung. Analog zur FIG 4 stehen sich hier ein erstes Gitter 75a und ein zweites Gitter 75b parallel gegenüber. Das erste Gitter 75a bildet hierbei die Hochspannungselektrode und ist mit dem Hochspannungsimpulsgenerator 46 verbunden. Das zweite Gitter 75b bildet die geerdete Gegenelektrode und steht mit dem Hochspannungsimpulsgenerator 46 in Verbindung. FIG. 9 shows an electrode system as a grid-grid arrangement. Analogous to FIG. 4 Here, a first grid 75a and a second grid 75b are parallel to each other. The first grid 75a forms the high voltage electrode and is connected to the high voltage pulse generator 46. The second grid 75b forms the grounded counter electrode and communicates with the high voltage pulse generator 46.

Eine hybride Entladung, wobei sich eine Elektrode 75a vollständig außerhalb einer zu behandelnden Faser-Suspension 39 befindet und eine zweite Elektrode 75b ganz oder teilweise in der Faser-Suspension 39 eingetaucht ist, wird mit einer alternativen Anordnung, bei welcher das Sieb als Elektrode 75a ausgestaltet ist, erzeugt. Das Sieb ist als eine Gitterelektrode ausgeführt und bildet die Hochspannungselektrode, welche mit dem Hochspannungsimpulsgenerator 46 in Verbindung steht. Auch die geerdete Gegenelektrode 76b ist als eine Gitterelektrode ausgeführt und steht mit dem Hochspannungsimpulsgenerator 46 in Verbindung.A hybrid discharge wherein an electrode 75a is located entirely outside a fiber suspension 39 to be treated and a second electrode 75b is wholly or partially immersed in the fiber suspension 39 is provided with an alternative arrangement in which the screen is configured as electrode 75a is generated. The screen is designed as a grid electrode and forms the high voltage electrode which is connected to the high voltage pulse generator 46. Also, the grounded counter electrode 76 b is designed as a grid electrode and is in communication with the high voltage pulse generator 46.

Um gepulste Entladungen im oberflächennahen Gasraum über der Faser-Suspension 39 oder über dem Papier zu erzeugen ist eine weitere Elektrodenanordnung möglich. Eine Hochspannungselektrode umfassend mehrere elektrisch miteinander verbundene Stabelektroden ist im oberflächennahen Gasraum der Faser-Suspension 39 oder dem Papier derart angeordnet, dass ihre Stäbe parallel zur Oberfläche verlaufen. Eine geerdete Gegenelektrode ist als massive Platte ausgeführt und in über die ganze Fläche verteilten äquidistanten Abständen zur Hochspannungselektrode angeordnet.In order to generate pulsed discharges in the near-surface gas space above the fiber suspension 39 or above the paper, a further electrode arrangement is possible. A high-voltage electrode comprising a plurality of electrically connected rod electrodes is arranged in the near-surface gas space of the fiber suspension 39 or the paper such that their rods are parallel to the surface. A grounded counter electrode is designed as a solid plate and arranged in distributed over the entire surface equidistant distances from the high voltage electrode.

In FIG 10 ist die aus FIG 1 bekannte schematische Pressenvorrichtung 11 vergrößert und detaillierter dargestellt. Das Papier 27 wird über zahlreiche Transportrollen und Walzen durch die Pressenvorrichtung 11 geführt und dabei zunehmend entwässert und verdichtet. Auf die genaue Funktion und Arbeitsweise der Pressenvorrichtung wird nicht näher eingegangen, da dem Fachmann eine Pressenvorrichtung ohne die erfindungsgemäße Elektrodenanordnung bekannt ist. Unmittelbar nach einem Eingangsbereich für das Papier 27 in die Pressenvorrichtung sind die Elektroden 47 und 48, welche einen Plasmareaktor innerhalb der Pressenvorrichtung 11 bilden, angeordnet. Die Elektroden 47 und 48 sind mit dem Hochspannungsimpulsgenerator 46 verbunden. Mittels der Elektroden 47,48 und des Hochspannungsimpulsgenerators 46 wird wie zuvor bereits beschrieben zwischen den Elektroden 47,48 ein Plasma erzeugt. Die Papierbahn 27 verläuft zwischen den Elektroden 47,48 und wird so beidseitig mit Plasma behandelt. Zusätzlich bildet die Papierbahn 27 eine bereits beschriebene dielektrische Barriere und kann somit die Streamerbildung begünstigen.In FIG. 10 is that out FIG. 1 known schematic press apparatus 11 enlarged and shown in more detail. The paper 27 is guided over numerous transport rollers and rollers through the press device 11 and thereby increasingly dewatered and compacted. On the exact function and operation of the press apparatus will not be discussed in more detail, since the person skilled in a press device without the electrode assembly according to the invention is known. Immediately after an entry area for the paper 27 into the press apparatus, the electrodes 47 and 48, which form a plasma reactor within the press apparatus 11, are arranged. The electrodes 47 and 48 are connected to the high voltage pulse generator 46. By means of the electrodes 47, 48 and the high-voltage pulse generator 46, a plasma is generated between the electrodes 47, 48 as already described above. The paper web 27 extends between the electrodes 47,48 and is treated on both sides with plasma. In addition, the paper web 27 forms a dielectric barrier already described and can thus favor the streamer formation.

Ausgangsseitig ist ein weiteres Elektrodenpaar 12a und 47' angeordnet. Die Elektrode 12a ist dabei als eine Rollenelektrode ausgestaltet, ähnlich der Rollenelektrode in FIG 11. Das Papier 27 wird durch die Rollenelektrode 12a geführt. Über der Rollenelektrode 12a ist in einem Abstand von ca. 1 cm die Elektrode 47' angeordnet. Zwischen den Elektroden 47' und 12a wird mittels des mit ihnen verbundenen Hochspannungsgenerator 46 ein Plasma zur Behandlung des Papiers 27 erzeugt.On the output side, a further electrode pair 12a and 47 'is arranged. The electrode 12a is configured as a roller electrode, similar to the roller electrode in FIG FIG. 11 , The paper 27 is guided by the roller electrode 12a. About the roller electrode 12a, the electrode 47 'is arranged at a distance of about 1 cm. Between the electrodes 47 'and 12a, a plasma for the treatment of the paper 27 is generated by means of the high-voltage generator 46 connected to them.

Bei der Anordnung gemäß FIG 11 stellt die Transportrolle 12 die geerdete Gegenelektrode 12a dar. Kraft- und formschlüssig wird das Papier 27 durch die Transportrolle 12 geführt. An die Drähte 12b, 12b' bis 12bn (n=10) wird die Hochspannung angelegt. Eine ebenfalls geerdete Gegenelektrode 12c, welche halbkreisförmig den Verlauf der Transportrolle 12 folgt, ist in einer nicht dargestellten Art und Weise mit der Transportrolle 12, insbesondere mit der Rollenelektrode 12a, elektrisch verbunden. Es wird somit eine Elektrodenanordnung mit konstantem Abstand gebildet, in welcher mittig die einzelnen Drähte 12b bis 12bn angeordnet sind. Über die Transportrolle 12 somit über die geerdete Elektrode 12a läuft das zu bearbeitende Papier 27 und wird somit jeweils von den zwischen den beiden Elektroden 12a und 12c angeordneten Drähten 12b bis 12bn mit Plasma und/oder Gasentladungen beaufschlagt.In the arrangement according to FIG. 11 the transport roller 12 represents the grounded counterelectrode 12a. The paper 27 is guided by the transport roller 12 in a force-fit and form-locking manner. To the wires 12b, 12b 'to 12b n (n = 10) the high voltage is applied. A likewise grounded counter electrode 12c, which follows the course of the transport roller 12 in a semicircular manner, is electrically connected in a manner not shown to the transport roller 12, in particular to the roller electrode 12a. It is formed with a constant distance thus an electrode assembly in which the individual wires are arranged centrally 12b to 12b n. The paper 27 to be processed thus passes over the transport roller 12 via the grounded electrode 12a and is thus subjected to plasma and / or gas discharges by the wires 12b to 12b n arranged between the two electrodes 12a and 12c.

Die Anordnung wird auch als gekrümmte Draht-Platte-Anordnung, welche einen Plasmareaktor bildet, bezeichnet.
The arrangement is also referred to as a curved wire-plate arrangement which forms a plasma reactor.

Claims (40)

  1. Device for guiding and/or deflecting and/or pressing and/or reeling and/or finishing process material during the production of paper (27), paperboard or board or during a treatment changing its properties, having at least two electrodes (47, 48) for the production of a plasma in the process material or in its immediate vicinity, the two electrodes (47, 48) being arranged on mutually opposite sides of the process material,
    characterized by a high-voltage pulse generator (46) connected to the electrodes (47, 48) for the generation of high-voltage pulses (66, 67) with a duration (62) of less than 10 µs.
  2. Device for guiding and/or deflecting and/or pressing and/or reeling and/or finishing process material during the production of paper (27), paperboard or board or during a treatment changing its properties, comprising a roll (12) coming into contact with the process material, the roll (12) being prepared as a first electrode (12a), it being possible for a plasma to be produced in the process material or in its immediate vicinity,
    characterized in that a high-voltage pulse generator (46) for the generation of high-voltage pulses is connected to the roll (12), and in that a second electrode (12b; 47) is arranged in such a way relative to the roll (12) that the process material can be transported or guided between the roll (12), in particular the first electrode (12a), and the second electrode (12b).
  3. Device according to Claim 2,
    characterized in that the roll (12) is arranged in such a way that it comes into contact with the process material, preferably a formed sheet, preferably a pressed sheet, in particular a paper web (27).
  4. Device according to Claim 3,
    characterized by at least one second roll, the second roll being arranged in such a way relative to the roll (12) that a two-dimensional process material, in particular the paper web (27), comes in contact with the rolls on both sides.
  5. Device according to one of Claims 2 to 4,
    characterized in that the roll (12) is part of a finishing system for paper (27), paperboard or board, preferably a coating device, or a device for calendering and/or supercalendering.
  6. Device according to one of Claims 2 to 4,
    characterized in that the roll (12) is part of a drying system (13) for paper (27), paperboard or board, which in particular is prepared for the evaporation of residual moisture.
  7. Device according to one of Claims 2 to 4,
    characterized in that the roll (12) is part of a pressing system (11) for paper, (27), paperboard or board, which in particular is prepared for pressing and/or dewatering and/or consolidation.
  8. Device according to one of Claims 2 to 7,
    characterized in that the roll (12) is prepared with a gas-permeable surface.
  9. Device according to one of Claims 2 to 8,
    characterized in that the roll (12) is prepared for the radial supply of a gas stream.
  10. Device according to one of Claims 1 to 8,
    characterized by means (81) for the flow of a gas stream against the process material.
  11. Device according to one of Claims 1 to 10,
    characterized by a high-voltage pulse generator (46) which is connected to the electrode or electrodes (12a, 12b).
  12. Method for the production or treatment of process material during the production or treatment of paper (27), board or paperboard, preferably for the operation of the device according to the invention, the process material being brought into contact with a preferably non-thermal, large-area plasma under atmospheric pressure, the plasma being produced in the direct vicinity of the process material or in the process material or in its immediate environment, a gas discharge, in particular a corona discharge, being produced under atmospheric pressure, the process material being brought in contact with the plasma on both sides or being treated on both sides by means of the gas discharge,
    characterized in that, in order to produce the plasma or the gas discharge between electrodes (43, 44; 47, 48), high-voltage pulses (66, 67) having a duration (62) of less than 10 µs are generated.
  13. Method according to Claim 12,
    characterized in that the process material used is a still unpressed and/or moist sheet or dry sheet in a paper or board production process.
  14. Method according to Claim 12 or 13,
    characterized in that the plasma or the gas discharge is used to bleach the process material.
  15. Method according to one of Claims 12 to 14,
    characterized in that radicals (59) which act on the process material are produced in the plasma or by means of the gas discharge.
  16. Method according to Claim 15,
    characterized in that, for various types of process materials in a paper, board or paperboard production process, radicals (59) of different type or composition are used, in particular in different process stages.
  17. Method according to Claim 15 or 16,
    characterized in that the process material is subjected to radicals (59) of different type or composition, preferably following one another chronologically, in a paper or board production process.
  18. Method according to Claim 16 or 17,
    characterized in that the process stages are chosen from the following stages:
    - pressing,
    - drying,
    - calendering,
    - reeling,
    - unwinding,
    - adhesion promotion, in particular before coating,
    - finishing, coating, in particular colour coating, supercalendering or calendering, in particular smoothing,
    - preparation for printing, in particular after calendering.
  19. Method according to one of Claims 15 to 18,
    characterized in that the radicals (59) produced are ozone (O3), hydrogen peroxide (H2O2), OH, HO2 and/or HO2 -.
  20. Method according to one of Claims 15 to 19,
    characterized in that a production rate of the radicals (59) and/or the composition of the radicals (59) produced is controlled and/or regulated by influencing amplitude (U), pulse duration (62) and/or pulse repetition rate (63) of the high-voltage pulses (66, 67).
  21. Method according to Claim 20,
    characterized in that, in order to control and regulate the production rate and/or the type of radicals (59) produced, a concentration of the radicals (59) produced is measured.
  22. Method according to Claim 20 or 21,
    characterized in that, in order to control and regulate the production rate or the composition of the radicals (59) produced, a property of the process material, preferably a quality property, in particular its opacity, gloss, whiteness, fluorescence or colour locus, is measured.
  23. Method according to either of Claims 21 and 22,
    characterized in that the concentration or the property is measured "online".
  24. Method according to one of Claims 20 to 23,
    characterized in that, for the purpose of regulation, the amplitude (U) of the high-voltage pulses (66, 67) is changed at constant repetition rate (63).
  25. Method according to one of Claims 20 to 24,
    characterized in that, for the purpose of regulation, the repetition rate (63) of the high-voltage pulses (66, 67) is changed at constant amplitude (U).
  26. Method according to one of the preceding claims,
    characterized in that the process material is enriched with oxygen in the region to which plasma is applied.
  27. Method according to one of the preceding claims,
    characterized in that, on the still unpressed sheet or moist sheet, a high-voltage pulse duration (62) of 100 ns to 1 µs is used.
  28. Method according to one of the preceding claims,
    characterized in that a high-voltage amplitude (U) corresponding to at least twice the value, preferably at least three times the value, of a corona initiation voltage is applied.
  29. Method according to one of the preceding claims,
    characterized in that, in the region to which plasma is applied, oxygen and/or water vapour with a partial pressure increased with respect to atmospheric conditions is fed in.
  30. Method according to one of the preceding claims,
    characterized in that, in order to generate the plasma or the corona discharge, a DC corona discharge is produced and the high-voltage pulses (66, 67) are superimposed on the DC corona discharge.
  31. Method according to one of the preceding claims,
    characterized in that a pulse repetition rate (63) between 10 Hz and 5 kHz, in particular or 10 kHz, is used.
  32. Method according to one of the preceding claims,
    characterized in that the power injection of electrical energy into the plasma is predominantly controlled via the regulation of amplitude (U), pulse duration (62) and pulse repetition rate (63) of the superimposed high-voltage pulses.
  33. Method according to one of the preceding claims,
    characterized in that high-voltage pulses (66, 67) having a duration (62) of less than 3 µs, preferably of less than 1 µs, preferably of less than 500 ns, are applied.
  34. Method according to one of the preceding claims,
    characterized in that a homogeneous, large-volume plasma having a high power density is produced without plasma pinches or breakdowns occurring.
  35. Method according to one of the preceding claims,
    characterized in that use is made of a DC voltage of such a level that a stable DC corona discharge is formed in the plasma only in conjunction with superimposed high-voltage pulses.
  36. Method according to one of the preceding claims,
    characterized in that the DC voltage used lies below that for stable operation without high-voltage pulse superimposition.
  37. Method according to one of the preceding claims,
    characterized in that the total amplitude used (DC voltage + pulse amplitude) lies above the static breakdown voltage of the electrode arrangement.
  38. Method according to one of the preceding claims,
    characterized in that the total amplitude used corresponds to two to five times the static breakdown voltage of the electrode arrangement.
  39. Method according to one of the preceding claims,
    characterized in that the amplitude (U) of the high-voltage pulses is between 10% and 1000% of the DC voltage used.
EP06763592A 2005-06-16 2006-06-08 Method and device for the improvement of paper quality Not-in-force EP1893809B1 (en)

Applications Claiming Priority (3)

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DE102005028045 2005-06-16
DE102005050845A DE102005050845A1 (en) 2005-06-16 2005-10-24 Method and device for improving paper quality
PCT/EP2006/063021 WO2006134067A2 (en) 2005-06-16 2006-06-08 Method and device for the improvement of paper quality

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EP1893809A2 EP1893809A2 (en) 2008-03-05
EP1893809B1 true EP1893809B1 (en) 2009-11-18

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EP (1) EP1893809B1 (en)
AT (1) ATE449211T1 (en)
DE (2) DE102005050845A1 (en)
WO (1) WO2006134067A2 (en)

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DE102013226936A1 (en) * 2013-12-20 2015-06-25 Siemens Aktiengesellschaft Process for treating paper fibers and paper fiber treatment device
DE102015109635B4 (en) * 2015-06-16 2023-12-07 Windmöller & Hölscher Kg Method for electrically treating a film and device for this purpose

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EP1067433A1 (en) * 1999-07-07 2001-01-10 Eastman Kodak Company High-efficiency plasma treatment of paper
DE10359847A1 (en) 2003-12-19 2005-07-28 Metsä Tissue Oyj Process and assembly to modify the surface characteristics of tissue paper or baking paper by exposure to plasma cloud

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WO2006134067A3 (en) 2007-03-08
DE102005050845A1 (en) 2006-12-21
ATE449211T1 (en) 2009-12-15
WO2006134067A2 (en) 2006-12-21
EP1893809A2 (en) 2008-03-05
DE502006005412D1 (en) 2009-12-31

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