EP2729614A1 - Cylindre sécheur à profilé adapté à la force d'extraction - Google Patents

Cylindre sécheur à profilé adapté à la force d'extraction

Info

Publication number
EP2729614A1
EP2729614A1 EP12730998.7A EP12730998A EP2729614A1 EP 2729614 A1 EP2729614 A1 EP 2729614A1 EP 12730998 A EP12730998 A EP 12730998A EP 2729614 A1 EP2729614 A1 EP 2729614A1
Authority
EP
European Patent Office
Prior art keywords
roll
coating
edge
roller
paper web
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.)
Withdrawn
Application number
EP12730998.7A
Other languages
German (de)
English (en)
Inventor
Jürgen ABRAHAM
Alexander Etschmaier
Hasso Jungklaus
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 EP2729614A1 publication Critical patent/EP2729614A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • 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
    • D21F5/02—Drying on cylinders
    • D21F5/021—Construction of the cylinders
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21G—CALENDERS; ACCESSORIES FOR PAPER-MAKING MACHINES
    • D21G1/00—Calenders; Smoothing apparatus
    • D21G1/02—Rolls; Their bearings
    • D21G1/0246—Hard rolls

Definitions

  • the present invention relates to drying cylinders for papermaking machines and, more particularly, to profiling of
  • Drying cylinders are usually heated with superheated steam to aid drying of the sheets of paper which have passed over them, allowing water to evaporate from the sheet interior and the sheet surface of the paper web. Since optimum paper quality can only be achieved with a homogeneous moisture distribution in the paper web, the most uniform possible temperature distribution on the drying cylinder surface is required. Drying cylinders are usually made of cast steel or welded steel construction, wherein the drying cylinder is formed as a hollow cylindrical, closed at the end faces of cylinder covers with integrally formed bearing journal, coat. However, this lid construction leads to a greater drying of the paper web in a range of about 30 to 40 mm from the edge of the cylinder jacket, which, if no countermeasures are taken, results in setting up the paper web edge and thus lower paper quality.
  • rollers whose surface is coated so that the adhesion of a guided over the roll surface paper web in the region of the paper edge is less than between the paper edges.
  • Embodiments of such rollers designed as a drying cylinder have a jacket surface which has a coating on the two regions adjacent to the cylinder cover, on the surface of which the paper web adheres worse than on the surface of the cylinder jacket between the two regions.
  • the coating can also extend over the entire working range of the roller, ie over the entire surface coming into contact with the paper web, the structure or composition of the coating changing in this case in the axial direction of the roller surface such that the adhesive force of the coating Paper web is higher in the central areas of the mantle surface, as in the direction of the roll edges.
  • the edge arrangement does not have its cause directly in the lower moisture content of the paper web edge zones compared with the rest of the paper web, but in the stronger adhesion of drier paper zones on the mantle surfaces of rolls or drying cylinders. Due to the greater adhesion, the force exerted on the paper web edges during the delivery of the sheet is greater than in the area between the edges, whereby the paper web edges are stretched relatively more and rise as a result. Lower adhesion edge zones for the paper web reduce the peel force of the paper web edges, thereby preventing the inhomogeneity of the sheet withdrawal and the associated stretch of the paper web edges.
  • the coating advantageously comprises, in embodiments, a marginal zone of the working area having a width in the range of 20 to 50 mm and in particular in the range of 30 to 40 mm, so that the effects of greater drying of the paper web in this area are effectively counteracted.
  • the coating comprises larger edge zones or the entire working area, wherein the surface properties of such a coating change in the axial direction of the roll surface.
  • the surface of the roll shell surface at the edge zones differs from the areas located therebetween in their chemical composition, whereby a targeted adjustment of the adhesive force to the degree of dryness of paper edges is possible.
  • the adaptation of the adhesion to the degree of dryness of paper edges Preferably, by a different in comparison to the edge zones-physical composition of the areas located between the edge zones of the
  • Roll shell surface wherein the adjustment can also be effected by a combination of chemically and physically deviating from the rest of the working surface structure of the edge zone coating.
  • the coating advantageously comprises a polyepoxide, a silicone polymer, a fluoropolymer, or mixtures thereof, as these have low adhesion to paper webs as compared to steel, cemented carbide, and ceramics.
  • Other embodiments may, possibly in addition, comprise a peripheral zone coating whose morphology differs from the morphology of the areas of the roll lateral surface located between the edge zone coatings.
  • the dissimilar morphology preferably comprises a different porosity.
  • the entire working area of the roll lateral surface is provided with a coating, wherein the composition and / or structure of the coating at the edge zones of the working area deviate from the composition and / or the structure of the coating in the areas of the roll surface between the edge zones of the working area ,
  • Figure 2 shows a schematic cross-section through a first drying cylinder, indicating work area, edge zones and located between the edge zones area
  • Figure 4 is a schematic cross section through a third
  • FIG. 5 shows a diagram to illustrate the course of the pull-off force of a paper fiber web from
  • Drying cylinder along the roll axis represents.
  • FIG. 1 shows a schematic perspective view of a drying cylinder 10, indicating the position of the working area 13 between the dashed lines, the edge zones 12 of the working area and the dot-dash lines lying between the dashed lines and the adjacent dot-dash lines Area 11.
  • Work area 13 here is the part of the lateral surface of a drying cylinder 10, which contacts the paper fiber web when used as intended.
  • the edge zones 12 extend over the edge regions of the working area 13, at which the stronger paper drying in the absence of Countermeasures leads to an edge of the paper or paper fiber web.
  • the position of the axis of rotation of the drying cylinder 10 is indicated in Figure 1 with a dash-dotted line.
  • the working area 13 does not occupy the entire lateral surface of the drying cylinder 10, but saves on both sides in each case a narrow peripheral edge area arranged with respect to the drying cylinder.
  • Such a design of the work area is not absolutely necessary, so that the working area 13 in embodiments can also coincide with the lateral surface of the roller 10.
  • the width of the edge zones 12 depends on the specific design and heating of a respective drying cylinder and the position and width of the working area 13 on the lateral surface of the cylinder 10.
  • the edge zones usually have a width in the range of about 20 to about 50 mm and preferably from the Range from 30 to 40 mm. As stated earlier, the difference
  • Adhesive force of a paper fiber web on the edge regions 12 is less than on the area located between the edge zones 11. Accordingly, the release force F A required for releasing the paper web from the work area 13 to the
  • Edge regions 12 lower than in the area between them, so that a leading edge for stretching of the paper fiber web edge is avoided.
  • the edge zones 12, as illustrated in FIGS. 2 to 4 are provided with a coating 14 whose surface properties differ from those of the surface of the working area 13 between the edge zones 12.
  • the intermediate region 11 different formation of the coatings 14 may by choosing a different material, a different structure, or a combination of deviating structure and other material.
  • the formation of the edge zone coating 14 differs from that of the intermediate region in either its chemical or physical composition, or both.
  • FIG. 2 illustrates a first embodiment of a drying cylinder with a separate edge zone coating 14.
  • the edge zone coatings 14 are each arranged in a recess comprising the edge zones 12 of the working area 13. If the working area 13 does not extend to the edges of the lateral surface of the drying cylinder 10, the recess filled with the coating 14 can also extend into the region of the lateral surface not covered by the working area 13; in embodiments also extend to the respective outer edge of the lateral surface.
  • Coating 15 is different.
  • FIG. 4 illustrates a particular embodiment of an embodiment according to FIG. 3, in which the two coatings 14 and 15 have different morphologies in the form of different porosities.
  • Porosity here is understood to be the presence of voids in the material whose dimensions do not extend beyond a few hundred micrometers.
  • the pores are shown in the figure as dark shapes, with size and density of these Structures in terms of an easily understandable representation are greatly exaggerated.
  • Morphology is understood in this document to be the structural structure of a coating or of a material in general.
  • Edge zone coatings 14 are preferably selected materials whose surface molecules have a lower attraction to molecules of the
  • Edge zone coatings 14 is less than in the remaining work area 11.
  • Expansion of the lateral surface of a drying cylinder 10 is shown in FIG.
  • the representation qualitatively reproduces the course of the pull-off force, wherein the zero level of the pull-off force lies below the x-axis extending in the axial direction of the drying cylinder.
  • the edge zone coatings 14 extend in the embodiment underlying the figure 5 up to the edges of the cylinder jacket surface.
  • the profile shows a gradual transition of the peel force at the boundary between the edge zone coating and between the edge zones located area 11, can be avoided by the abrupt tension changes in the release of a paper web.
  • a corresponding graduation can be achieved, for example, by changing the composition of the coating in the edge region or by an interstructural toothing of edge zone coating and adjacent region 11.
  • the graduation of the peel force need not be limited to a small area at the junctions between the edge zones 12 and the area located therebetween, as illustrated in FIG Embodiments also extend over the entire width of the roller, wherein a so continuously changing over the roll width deduction force at the roll edges always has smaller values, as in the central regions of the roll 10th
  • the coating is formed by a polymer.
  • the polymers used for this purpose are, in particular, thermosets and thermoplastics, which can be produced on the basis of one-component and two-component systems. Particularly suitable are thermosets whose decomposition temperature is so far above the temperature of the edge zone coatings that the respective thermoset behaves elastically. In an analogous manner, thermoplastics whose glass transition temperature is so far above the operating temperature of the edge zone coatings that when using the coated with the polymer zone no disturbing softening of the polymer can occur. As a rough guideline for the minimum difference between operating temperature and decomposition or
  • Glass transition temperature can be specified as 20 ° C. Under operating temperature is the operating temperature of the edge zone coatings or the lateral surface of the drying cylinder generally during normal use to understand.
  • the edge zone coatings 14 are formed using at least one of a polyepoxide, silicone polymer or fluoropolymer. It is also possible to use polymer mixtures containing such substances. In particular, fillers such as. As fibers or particles embedded to z in a known manner. B. adjust the elasticity, abrasion resistance, thermal conductivity or color appearance to desired values.
  • edge zone coatings 14 epoxy resins with filler particles of polyfluoroethylene (PFE) embedded therein and in particular of polytetrafluoroethylene (PTFE) may be used. Epoxy resins show in the non-crosslinked or partially crosslinked state a good wetting of steel surfaces and therefore allow a firm connection with the roll core of a drying cylinder.
  • PFE polyfluoroethylene
  • PTFE polytetrafluoroethylene
  • the viscosity of epoxy resins can be reduced by the addition of solvents, such as alcohols or ketones, whereby e.g. B. an impregnation of z. B. porous surfaces is possible. Coating can be done by pouring, spraying or using
  • Brushing tools such. B. brushing or filling.
  • An impregnation for example a previously applied porous thermal spray coating, can also be carried out by means of an immersion bath.
  • Fluoropolymer-produced edge zone coatings are characterized by high chemical and thermal stability and excellent anti-adhesive behavior.
  • Randzone coatings 14 formed from fluoropolymers are also very resistant under dynamic loads.
  • silicone polymers for example, silicone resins having silicone oils incorporated into their matrix to improve the anti-sticking effect, are suitable for forming edge zone coatings 14 because of their excellent thermal and chemical resistance.
  • edge zone coatings can be assisted by choice of materials having a lower thermal conductivity compared to the surface of a drying cylinder 10 located between the edge zone coatings 14.
  • a correspondingly lower Thermal conductivity reduces the heat transfer through this area of the roll shell and thereby reduces the drying of the paper web edges so that, as a result, they adhere less strongly to the roll shell and can be easily detached therefrom.
  • this effect can be achieved by using z.
  • ceramics but also with the use of polymeric materials as described above can be achieved.
  • the lower adhesion of the paper web edges on the edge zone coatings 14 compared to the other work surface 11 is achieved by the combination of two effects: the lower attraction force on paper web molecules and the lower heat transport to the paper web.
  • the thermal conductivity of a coating can be influenced not only by the choice of the coating material but also on the morphology of the coating.
  • two or more materials of different thermal conductivity may be arranged side by side in complementary patterns within a border zone coating, so that a thermal conductivity of the coating averaged over the surface portions is formed.
  • materials with lower thermal conductivity can be arranged for example in lower layers to minimize the heat conduction, while the surface layer is designed primarily with respect to a low attraction force for molecules of the paper fiber web.
  • Edge zone coatings 14 may also be expressed in a different from the rest of the work surface 11 porosity of the material.
  • the edge zone coating 14 z. B. be formed by a thermal spray coating.
  • the order of the coating material is preferably carried out by using a thermal spraying method such as high-speed flame spraying, which is known by the acronym HVOF.
  • the spray coating is preferably carried out in several strokes, for example with 10 to 100 strokes, each stroke each applying a thin layer of the coating material to the underlying material.
  • the porosity of the layers can be determined by the ratio of fuel to oxygen and the rate of delivery of the film used
  • the porosity can be varied across the depth of the edge zone coatings 14.
  • the porosity of the edge zone coatings 14 is preferably between 2 and 10 percent or varies in a profiling preferably within this range, wherein porosity means the area proportions of the pores in a transverse cross section passing through the material.
  • porosity means the area proportions of the pores in a transverse cross section passing through the material.
  • the entire working surface is provided with a thermal sprayed coating, in preferred embodiments with a Cemented carbide layer, wherein the porosity of the edge zone coatings 14 is higher than that of the intermediate region 11 of the rest
  • the porosity of the coating 15 in region 11 is zero. In practice, the achievable minimum porosity depends on the particular thermal spray coating method and coating material used. Porosities of less than 1 percent down to 0.5 percent are currently quite realistic.
  • the coating parameters are adjusted to achieve a porosity in the range of about 2 to about 10 percent.
  • the pores of the edge zone coatings 14 are then filled in an impregnation process with one of the polymeric materials described above.
  • the surface of the edge zone coatings 14 is coated with one of the abovementioned polymeric materials, wherein the outer surface of the polymeric coating is expediently arranged identically to the outer surface of the coating 15.
  • the edge zone coating 14 extends not only over areas bounded by edge zones 12 but over all or at least a substantial part of them
  • the surface of the drying cylinder can be covered with a thermal spray coating whose porosity from the edge regions of the cylinder 10 to its center regions continuously decreases.
  • the resulting axial adhesion profiling can be enhanced by impregnating the porous coating as described above. Drying cylinders of the type described above prevent stronger forces acting on the edge of a roll of paper web from a roll and, in particular, a drying cylinder, than forces acting on the remainder of the web. Setting up paper web edges is effectively countered with little equipment expense.
  • the invention is usable not only for drying cylinders but also for other rolls in dry sections or other sections of paper machines.

Landscapes

  • Paper (AREA)
  • Drying Of Solid Materials (AREA)

Abstract

L'invention concerne un cylindre, notamment un cylindre sécheur (10), dont l'enveloppe comporte une couche (14) sur la zone de travail (13) prévue pour être en contact avec une bande de papier guidée au-dessus de celle-ci, cette couche étant formée de sorte que l'adhésion de la bande de papier à sécher est plus faible sur les zones périphériques de la zone de travail (13) que dans les zones (11) de l'enveloppe du cylindre situées entre les zones périphériques (12).
EP12730998.7A 2011-07-06 2012-07-04 Cylindre sécheur à profilé adapté à la force d'extraction Withdrawn EP2729614A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE201110078743 DE102011078743A1 (de) 2011-07-06 2011-07-06 Abzugskraftprofilierter trockenzylinder
PCT/EP2012/062983 WO2013004723A1 (fr) 2011-07-06 2012-07-04 Cylindre sécheur à profilé adapté à la force d'extraction

Publications (1)

Publication Number Publication Date
EP2729614A1 true EP2729614A1 (fr) 2014-05-14

Family

ID=46420226

Family Applications (1)

Application Number Title Priority Date Filing Date
EP12730998.7A Withdrawn EP2729614A1 (fr) 2011-07-06 2012-07-04 Cylindre sécheur à profilé adapté à la force d'extraction

Country Status (4)

Country Link
EP (1) EP2729614A1 (fr)
CN (1) CN103842586A (fr)
DE (1) DE102011078743A1 (fr)
WO (1) WO2013004723A1 (fr)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105358764A (zh) * 2013-07-04 2016-02-24 福伊特专利有限公司 具有低表面能的辊包覆物
ITUA20163151A1 (it) * 2015-05-08 2017-11-04 A Celli Paper Spa Metodo di rivestimento di cilindri per impianti di cartiera e cilindri così ottenuti

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3926716A (en) * 1974-03-19 1975-12-16 Procter & Gamble Transfer and adherence of relatively dry paper web to a rotating cylindrical surface
FI53606C (fi) * 1977-02-04 1978-06-12 Eero Arthur Irpola Foerfarande foer utjaemnande av fuktighetsprofilen vid en cylindertork samt medel foer utfoerande av foerfarandet
FI20002122A (fi) * 2000-06-02 2001-12-03 Metso Paper Inc Sovitelma paperikoneen kuivatusosan alun parantamiseksi
EP1985754B1 (fr) * 2002-10-07 2016-08-10 Georgia-Pacific Consumer Products LP Procédé de crêpage pour réaliser une feuille cellulosique absorbante, et feuille absorbante
DE102006003386A1 (de) * 2006-01-24 2007-07-26 Reichel, Walter, Dipl.-Ing. Vorrichtung und Verfahren zur Oberflächenbehandlung von Walzen in der Papierindustrie

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO2013004723A1 *

Also Published As

Publication number Publication date
WO2013004723A1 (fr) 2013-01-10
DE102011078743A1 (de) 2013-01-10
CN103842586A (zh) 2014-06-04

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