EP4328376A1 - Formeur à tamis oblique - Google Patents

Formeur à tamis oblique Download PDF

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Publication number
EP4328376A1
EP4328376A1 EP23188826.4A EP23188826A EP4328376A1 EP 4328376 A1 EP4328376 A1 EP 4328376A1 EP 23188826 A EP23188826 A EP 23188826A EP 4328376 A1 EP4328376 A1 EP 4328376A1
Authority
EP
European Patent Office
Prior art keywords
sieve
section
horizontally extending
essentially horizontally
former
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.)
Pending
Application number
EP23188826.4A
Other languages
German (de)
English (en)
Inventor
Egon FRIESENHAHN
Rainer Falkenberg
Andreas Schilz
Ralf Schröder
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Voith Patent GmbH
Original Assignee
Voith Patent GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Voith Patent GmbH filed Critical Voith Patent GmbH
Publication of EP4328376A1 publication Critical patent/EP4328376A1/fr
Pending legal-status Critical Current

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Classifications

    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F1/00—Wet end of machines for making continuous webs of paper
    • D21F1/48—Suction apparatus
    • D21F1/50—Suction boxes with rolls
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F9/00—Complete machines for making continuous webs of paper
    • D21F9/02—Complete machines for making continuous webs of paper of the Fourdrinier type
    • 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
    • D21H13/00—Pulp or paper, comprising synthetic cellulose or non-cellulose fibres or web-forming material
    • D21H13/10—Organic non-cellulose fibres
    • D21H13/20—Organic non-cellulose fibres from macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
    • D21H13/26—Polyamides; Polyimides

Definitions

  • the present invention relates to an inclined screen former for producing a fibrous web, in particular a long-fiber paper or wet fleece web, from at least one fibrous suspension, with a screen which runs over a circumferential region of a breast roller and then runs in the direction of travel of the screen, at least in sections at an angle to the horizontal, before it is deflected in a substantially horizontal direction at a deflection point, wherein in this oblique section of the sieve at least one headbox applies at least a part of the at least one fibrous suspension to the upper side of the sieve, and at least one drainage element to the underside for dewatering the at least a part of the at least one
  • the fibrous suspension applied to the sieve is arranged, the headbox comprising a front wall which, together with the sieve, defines an outlet gap for the at least one fibrous suspension.
  • the invention further relates to the use of such an inclined wire former for producing a long fiber paper or wet fleece web, in particular a battery separator paper web or an aramid paper web or a capacitor paper web.
  • Such an inclined screen former is, for example, from the German published patent application DE 10 2004 047 518 A1 known and is manufactured and sold by the applicant under the name “Hydroformer”. It is primarily used to produce long-fiber papers and wet fleeces, with this type of sheet formation using fibers and fiber mixtures of various materials with a length of 1 to 40 mm.
  • Some long fiber paper or wet fleece webs such as battery separator paper webs or aramid paper webs or capacitor paper webs, have very high quality requirements. As a rule, they should have the lowest possible weight per unit area and be free of so-called “pinholes”, ie small ones holes, be. This requires a very good formation. Agglomerations of fibers must be prevented and the web should have a thickness that is as uniform as possible and a cross-sectional mass profile that is as uniform as possible. At this point there is still further potential for improvement in the known inclined screen formers.
  • the task is solved by a generic fourdrinier former described at the outset, in which the front wall of the headbox extends in the direction of wire travel beyond the deflection point of the wire, so that the outlet gap is arranged above the essentially horizontally extending section of the wire.
  • “essentially horizontally extending section of the sieve” means that this section of the sieve is either extends exactly horizontally or has only a small angle to the horizontal, namely an angle of less than 20°, preferably less than 10°, more preferably less than 5°. In any case, the angle to the horizontal that the “essentially horizontally extending section of the sieve” has is smaller in magnitude than the angle to the horizontal that the oblique sieve section has.
  • the present invention is a special combination of an inclined wire former and a fourdrinier former, in which the fibrous suspension is passed through the special former largely in the area of the inclined sieve section and only a small part in which is essentially horizontal extending sieve section is applied to the sieve.
  • the at least one drainage element arranged on the underside of the oblique section of the sieve extends in the direction of the sieve running beyond the deflection point of the sieve, so that it ends below the essentially horizontally extending section of the sieve. In this way it can be ensured that in all areas in which fibrous suspension is applied to the sieve, drainage also takes place through the sieve by the at least one drainage element.
  • the front wall of the headbox has a curvature or a kink or the like in the area of the deflection point of the wire, so that the distance between the front wall of the headbox and the wire in the direction of wire travel tapers, preferably continuously. Due to the distance tapering in the direction of the sieve, the flow speed of the fibrous suspension to be applied to the sieve can be kept approximately constant.
  • a fixing suction device is arranged under the essentially horizontally extending sieve section, by means of which the Position of the waterline of the at least one fibrous suspension on the essentially horizontally extending sieve section can be determined.
  • the fibers still have turbulence energy from the headbox and can therefore be deposited in the sheet structure while still in motion.
  • the watery state in this leaf formation area is clearly illustrated by the side plan view of the essentially horizontally extending screen section and a shiny, reflective surface can be seen. This phenomenon stops almost abruptly at the so-called “waterline” and the surface then appears relatively matt in the direction of the wire. The position of the waterline can be adjusted using the suction cup.
  • At least one further dewatering element in particular a suction box, can be arranged after the fixing suction device under the essentially horizontally extending sieve section, by means of which the fibrous web can be further dewatered.
  • the aim is to achieve a specified dry content of the fibrous web before it is removed from the sieve.
  • At least one steam blowing box is arranged above the essentially horizontally extending sieve section.
  • the steam can reduce the viscosity of the water in the fibrous web, which promotes dehumidification of the fibrous web, for example by means of suction boxes arranged below the sieve.
  • At least one upper sieve can also be arranged above the essentially horizontally extending sieve section. This allows the fibrous web to be drained both downwards through the sieve and upwards through the upper sieve. This not only shortens the required drainage distance, but also leads to an improvement in the surface of the fibrous web.
  • the screen can have a low air permeability of less than 410 CFM and/or a high retention value of more than 100 FSI. This means that fibrous webs can also be reliably produced and transported with low material density.
  • the essentially horizontally extending section of the sieve is at least partially laterally surrounded by edge delimiters.
  • a further aspect of the present invention relates to the use of a previously described inclined wire former according to the invention for producing a long fiber paper or wet fleece web, in particular a battery separator paper web or an aramid paper web or a capacitor paper web. It is precisely for these webs with their high quality requirements that the advantages of the inclined screen former according to the invention come into play.
  • the inclined screen former according to the invention is preferably operated in such a way that the waterline of the at least one fiber suspension is set on the essentially horizontally extending screen section. This prevents the fiber suspension from flowing back.
  • the consistency of the at least one fiber suspension can be less than 0.3%, preferably less than 0.02%. Low material densities are particularly advantageous for battery separator paper webs or aramid paper webs or capacitor paper webs. The same applies if the long-fiber paper or wet fleece web has a basis weight of less than 20 g/m 2 .
  • FIG 1 shows schematically an inclined wire former 10' known from the prior art with a headbox 20' and a screen 30'.
  • the sieve 30' designed as an endless sieve loop, moves clockwise over a series of rollers.
  • One of these rollers is designed as a breast roller 32'.
  • the wire 30' moves upwards from the breast roller 32' at an angle obliquely to the horizontal direction.
  • the headbox 20' applies a fibrous suspension to the top of the screen 30'.
  • a drainage element 40 ' is arranged on the underside of the inclined sieve section.
  • the headbox 20' has a front wall 22' which, together with the sieve 30', defines an outlet gap 24' for the pulp suspension. Behind the drainage element 40' there is a fixing suction device 50', by means of which the waterline of the fiber suspension can be adjusted. Both the outlet gap 24', as well as the drainage element 40' and the fixing suction cup 50' are arranged here in the inclined area of the sieve 30'. Only then is the sieve 30' deflected in a substantially horizontal direction by means of a first deflection roller 34'.
  • FIG. 2 now shows schematically an embodiment of an inclined screen former 10 according to the invention. Similar or identical components to those in Figure 1 shown and described above are given the same reference numerals, but without a prime. Below we will primarily look at the differences between the two embodiments and otherwise refer to the statements above Figure 1 referred.
  • the inclined screen former 10 is particularly characterized in that the outlet gap 24 is already arranged above the essentially horizontally extending section of the screen 30.
  • the front wall 22 of the headbox 20 extends over a deflection point at which the sieve 30 transitions from an oblique sieve section into the essentially horizontally extending sieve section. In this way, it can be reliably prevented that part of the fibrous suspension emerging from the outlet gap can flow back onto the sieve 30, which is detrimental to the quality of the fibrous web to be produced.
  • the front wall 22 is curved in the area of the deflection point in such a way that its distance from the screen 30 tapers, preferably continuously, in the direction of the screen running.
  • the drainage element 40 arranged under the sieve 30 also extends beyond the deflection point to below the essentially horizontally extending sieve section. Because the top of the drainage element 40 is curved, it guides the sieve 30 and defines the deflection point. A deflection roller can therefore be dispensed with here.
  • the fixing suction device 50 which follows the drainage element 40 in the direction of the wire running, is thus arranged here under the essentially horizontally extending section of the sieve 30. Consequently, the waterline of the fibrous suspension emerging from the outlet gap 24 is also located on the essentially horizontally extending section of the sieve 30.
  • the sieve 30 is preferably positioned laterally from in at least in the area between the outlet gap 24 and the waterline Figure 2 edge limiters, not shown, which prevent the fiber suspension from running down the side of the sieve 30.
  • a steam blowing box 70 and/or a top sieve 80 can be arranged above the essentially horizontal sieve section.
  • the dehumidification of the fibrous web can be carried out efficiently after the waterline, or the overall length of the inclined screen former 10 can be reduced, which is required in order to be able to hand over the fibrous web with a predetermined dry content to a section of the manufacturing machine following the inclined screen former 10.
  • Further dewatering elements 60 are preferably arranged under the sieve in the area of the steam blower box 70 and/or the upper sieve 80.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Paper (AREA)
EP23188826.4A 2022-08-22 2023-08-01 Formeur à tamis oblique Pending EP4328376A1 (fr)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE102022121105.3A DE102022121105A1 (de) 2022-08-22 2022-08-22 Schrägsiebformer

Publications (1)

Publication Number Publication Date
EP4328376A1 true EP4328376A1 (fr) 2024-02-28

Family

ID=87553848

Family Applications (1)

Application Number Title Priority Date Filing Date
EP23188826.4A Pending EP4328376A1 (fr) 2022-08-22 2023-08-01 Formeur à tamis oblique

Country Status (4)

Country Link
US (1) US20240060238A1 (fr)
EP (1) EP4328376A1 (fr)
CN (1) CN117604802A (fr)
DE (1) DE102022121105A1 (fr)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102004047518A1 (de) 2004-09-28 2006-03-30 Voith Paper Patent Gmbh Verfahren und Schrägsiebformer einer Maschine zur Herstellung einer Faserstoffbahn aus mindestens einer Faserstoffsuspension
EP2096207A1 (fr) * 2008-02-28 2009-09-02 Voith Patent GmbH Dispositif de moulage à tamis oblique d'une machine destinée à la fabrication d'une bande de matière fibreuse à partir d'au moins une suspension de matière fibreuse
DE102014107725A1 (de) * 2014-06-02 2015-12-03 TRüTZSCHLER GMBH & CO. KG Verfahren zur Herstellung eines strukturierbaren mehrschichtigen Vlieses und mehrschichtiges Vlies

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102004047518A1 (de) 2004-09-28 2006-03-30 Voith Paper Patent Gmbh Verfahren und Schrägsiebformer einer Maschine zur Herstellung einer Faserstoffbahn aus mindestens einer Faserstoffsuspension
EP2096207A1 (fr) * 2008-02-28 2009-09-02 Voith Patent GmbH Dispositif de moulage à tamis oblique d'une machine destinée à la fabrication d'une bande de matière fibreuse à partir d'au moins une suspension de matière fibreuse
DE102014107725A1 (de) * 2014-06-02 2015-12-03 TRüTZSCHLER GMBH & CO. KG Verfahren zur Herstellung eines strukturierbaren mehrschichtigen Vlieses und mehrschichtiges Vlies

Also Published As

Publication number Publication date
US20240060238A1 (en) 2024-02-22
DE102022121105A1 (de) 2024-02-22
CN117604802A (zh) 2024-02-27

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