Classifications

• • 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
  • D21H23/00—Processes or apparatus for adding material to the pulp or to the paper
  • D21H23/02—Processes or apparatus for adding material to the pulp or to the paper characterised by the manner in which substances are added
  • D21H23/22—Addition to the formed paper
  • D21H23/32—Addition to the formed paper by contacting paper with an excess of material, e.g. from a reservoir or in a manner necessitating removal of applied excess material from the paper
  • D21H23/34—Knife or blade type coaters

Definitions

• the invention relates to a device for applying coating material to a running material web, in particular a paper or cardboard web, according to the preamble of claim 1.
• Devices for coating running material webs, in particular paper or cardboard webs, with a counter roll deflecting the web, an application system with a metering element being arranged in the wrapping area of the counter roller for setting the desired application weight.
• the surface of the metering element which extends over the working width, forms with the counter roller an application gap converging in the direction of web travel, via which the coating material is guided to the web.
• the desired application weight can be set via the gap width at the narrowest point of the application gap, which is referred to as the metering line.
• DE-OS 36 20 374 describes a device without scooping application roller, in which the coating material is pumped into the converging gap between the counter-roller and a rake element via a channel.
• Rotating squeegee rods or distribution elements which are arc-shaped in cross section are provided as squeegee elements and can be pressed against the counter roller in an elastically supported manner in order to be able to adjust the line pressure on the metering line.
• the invention has for its object to improve a generic device for applying coating material so that different coating materials at high web speeds can be applied evenly and trouble-free even with low application weights.
• the converging application gap for adjusting the hydrodynamic pressure and the gap width on the metering line can be changed.
• the edge with the small radius on the dosing line avoids the occurrence of fiimsplitting and thus leads to a more even application.
• the metering element is supported on a parallel to the counter-roller axis, cylindrical support element and pivotable about an axis which extends coaxially to the cylinder axis of the support element.
• the support element is a driven, coating material in the application gap demanding roller, which takes over the function of a pump, via the rotational speed of the flow rate to the metering / pre-metering gap can be influenced.
• the rotatable rake bar on the dosing line according to claim 6 ensures longer service life and self-cleaning of the dosing / pre-dosing element, since it has considerably less wear and tear than a fixed dosing element subject to.
• the inelastic support of the metering element according to claim 7 enables the setting of a certain gap width on the metering line regardless of the hydrodynamic pressure. Alternatively, a certain hydrodynamic pressure can also be set, then the metering element is pressed against the counter roller at a preselected pressure.
• the ink feed in the application gap is calmed by the guide plate arranged in front of the metering element in the web running direction. This ensures an even application and thus makes it possible to reduce the pressure in the application gap without creating uncovered parts on the web.
• FIG. 1 is a side view of a device with a wedge-shaped metering element which is fastened on a pivotable cylindrical support element
• FIG. 3 shows the side view of a device with a scooping application roller
• FIG. 4 shows an enlarged detail from FIG. 3,
• Fig. 5 shows a device in which the metering line is limited by a rotatable doctor rod.
• the application device has a driven counter roll 1, from which the material web 2 - a paper or cardboard web with a width of 8 m and more - is deflected.
• a cylindrical support element 3 is arranged, which is a Intermediate space between the support element 3 and the counter roller 1 arranged metering element 4 supports.
• a feed channel 5 In the web running direction in front of the metering element 4 there is a feed channel 5, via which coating material - in the present example coating color - is guided to the web 2 via the surface 6 of the metering element 4.
• the surface 6 of the metering element 4 facing the counter roller 1 forms with the counter roller 1 an application gap converging in the direction of the web, the gap width of which at the narrowest point (metering line 7) is less than 2 mm.
• the elements described above (counter roller 1, support element 3, metering element 4, feed channel 5) extend over the entire working width, ie the width of the web 2, with a constant cross section.
• the length of the surface 6 of the metering element 4 as far as the metering line 7 measured in the direction of web travel between 5 mm and 50 mm.
• the metering element 4 is rigidly attached to the outer surface of the support element 3. Its surface 6 guiding the coating color extends in the web running direction (from the left to the right in the figures) approximately tangentiai with increasing distance from the lateral surface of the support element 3. In the embodiment according to FIG. 1, this is realized constructively by means of a metering element 6 which is wedge-shaped in cross section, in the embodiment according to FIG. 2 by a scraper knife 8 which is correspondingly fastened and supported on the outer surface of the support element 3.
• the support element 3 is mounted so that it can pivot about a pivot axis 9 within limits.
• the pivoting takes place by means of two levers 10, each fastened to the end faces of the support element 3, which can be pivoted by means of two pneumatic cylinders 11, 12 adjustable in the opposite direction. Since the distance 13 of the surface 6, referred to as radius 13, increases continuously from the pivot axis 9 of the metering element 6 in the web running direction to the metering line 7, both the geometry of the application gap formed by it together with the counter-roller 1 and the width of the gap on the Set metering line 7 by swiveling the support element 3.
• the pivoting movement of the metering element 4 in the counterclockwise direction, in which the gap width at the metering line 7 is reduced, is limited by a mechanical stop 14, so that a minimum gap width is not undershot.
• a certain hydrodynamic pressure can be set, the gap width being variable. A certain pressure is then set in the pneumatic cylinder 12 without a mechanical stop, for which a corresponding hydrodynamic pressure builds up in the application gap.
• the metering element 4 dodges and opens the application gap; z. B. when passing through a thickened adhesive point of the paper web.
• the support element 3 is preferably designed as a double-walled hollow body through which a cooling liquid flows. In this way, thermal deformations that would be transferred to the metering element 4 are avoided. Cooling also reduces the build-up of coating color.
• the carrying element 3 can be made relatively slim. In the case of large working widths, it is supported on its underside to avoid bending. As shown in FIG. 1, this is expediently carried out with a continuous bar 15 which is pressed against the underside by means of a series of adjusting screws 16.
• the surface 6 of the dosing element 4 ends at the dosing line 7 with an edge whose radius is less than 8 mm.
• the edge thus forms an abrupt end of the application gap on the metering line 7 in order to keep the forces acting radially away from the counter roller 1 on the coating ink as low as possible.
• a guide plate 17 is arranged, which, adapted to the lateral surface of the carrying element 3, is curved at a distance from it and thus forms the feed channel 5 of the coating color into the application gap.
• the guide plate 17 extends into the application gap or ends at a short distance in front of the metering element 4.
• the coating color is pumped into the feed channel 5 with a controllable pump 18 in excess.
• the Excess amount runs back through the guide plate 17 from the incoming coating color against the web erection via the rear side 19 into a collecting trough 20.
• the support element consists of a driven roller 21 which conveys the coating color into the application gap.
• an additional final metering device 22 is arranged, which contains a doctor blade 23 as the final metering element, which can be adjusted in a known manner Angle and contact pressure against the web 2 guided by the counter roll 1 can be pressed.
• the coating knife doctored by the doctor blade 23 runs back into an ink roller 24 arranged below the application roller 21, from which it is conveyed together with freshly supplied coating ink into the application gap.
• a guide plate 17 is also arranged on the web inlet side and separates the inlet from the returning excess in the manner described above.
• the area of the order gap with the dosing element 6 is shown enlarged in FIG. 4:
• the metering element 4 is also wedge-shaped in cross section and ends at the metering line 7 in a sharp edge. However, it is not attached to the applicator roller 21, but is only supported on it.
• the application roller 21 rotates under the metering element to convey coating color into the application gap.
• the gap width at the metering line is a maximum of 2 mm and the length of the surface 6 of the metering element which guides the coating color up to the metering line 7 is between 5 mm and 50 mm.
• the guide plate 17 extends up to the vicinity of the order space, the distance of its end from the metering line is a maximum of 80 mm.
• the dosing element 4 is attached to the end of a pivot lever 25 which is pivotably mounted about the axis of rotation 26 of the application roller 21 in order to be able to adjust the geometry of the application gap in the manner described in the embodiment according to FIG.
• FIG. 5 also shows an embodiment with an application roller 21 which conveys the coating color into the feed channel 5.
• the metering element 4 is pivotably mounted about the axis of rotation 26 of the application roller 21. It has a wedge-shaped inlet flank, which forms the feed channel 5 with the guide plate 17.
• a holder 27 for a rotatable doctor rod 28 is fitted into the metering element 4.
• the outer surface of the driven doctor rod 29 is either smooth or has elevations and depressions; preferably in the form of circumferential grooves which, for. B. were generated by wrapping with a wire or by incorporating annular or spiral grooves.
• the circumference of the rake bar 28 adjoins the inlet flank tangentiai, so that the tear-off edge on the metering line 7 is formed by it.
• the radius of the doctor rod 28 is a maximum of 8 mm, it is expediently driven by the drive of the application roller 21.
• the embodiment according to FIG. 5 has the advantage that the wear of the rotatable doctor rod at the critical point, namely the metering line 7, is substantially less than that of a metering element which is rigid in this area. Furthermore, the rake bar 28 can be easily replaced when worn.

Landscapes

• Coating Apparatus (AREA)
• Paper (AREA)
• Vehicle Interior And Exterior Ornaments, Soundproofing, And Insulation (AREA)
• Application Of Or Painting With Fluid Materials (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (1)

Family

ID=6452695

Family Applications (1)

Country Status (7)

Cited By (1)

Families Citing this family (2)

Citations (3)

Family Cites Families (1)

• 1992
  • 1992-02-27 DE DE4205993A patent/DE4205993A1/de not_active Withdrawn
  • 1992-12-24 AT AT93902130T patent/ATE128501T1/de not_active IP Right Cessation
  • 1992-12-24 DE DE59203854T patent/DE59203854D1/de not_active Expired - Fee Related
  • 1992-12-24 ES ES93902130T patent/ES2080606T3/es not_active Expired - Lifetime
  • 1992-12-24 EP EP93902130A patent/EP0583434B1/de not_active Expired - Lifetime
  • 1992-12-24 WO PCT/EP1992/002996 patent/WO1993017181A1/de active IP Right Grant
  • 1992-12-24 JP JP5514475A patent/JPH06507120A/ja active Pending
• 1993
  • 1993-10-26 FI FI934734A patent/FI98543C/fi not_active IP Right Cessation

Patent Citations (3)

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