EP2909002A1

EP2909002A1 - Device and method for producing structured plastic yarns, plastic yarn and spiral fabric made from plastic yarn

Info

Publication number: EP2909002A1
Application number: EP13776803.2A
Authority: EP
Inventors: Jürgen ABRAHAM
Original assignee: Voith Patent GmbH
Current assignee: Voith Patent GmbH
Priority date: 2012-10-19
Filing date: 2013-10-15
Publication date: 2015-08-26
Also published as: US20150217502A1; WO2014060382A1; CN104812551A

Abstract

A device (1) for producing plastic spirals (13) for use in a machine for producing a fibrous web, comprising at least two rolls (4, 5), between which an adjustable roll nip (6) is formed. The rolls (4, 5) have a shape which differs at least in regions from a cylinder shape and/or have a surface structure (10) at least in regions on the surface thereof.

Description

Apparatus and method for producing structured plastic yarns, plastic yarn and spiral wire of plastic yarn

The invention relates to a device for producing spirals of plastics, a method for producing plastic filaments by means of such a device, a plastic spiral produced in this way a spiral wire of such plastic filaments, according to the preambles of the independent claims. Textile fabrics are found in a variety of positions in machines for making fibrous web material, such as in paper and board machines. In the forming section, the sheets serve for sheet formation and primary dewatering, in the press section for receiving water squeezed out of the fiber web material, in transfer positions for transfer to the next machine section and in all sections for supporting the fiber web material.

In the dryer section of a fiber web machine, fabrics - commonly referred to as dryer fabrics - serve, in addition to supporting the fibrous web, to increase the drying efficiency and the energy efficiency of the dryer section. The dryer fabrics must be thin yet dimensionally stable at low elongation, must not mark the fiber web material, carry no air, optimally dissipate moisture, exhibit optimum sheet dispensing properties and ensure a uniform drying profile across the width of the fiber web material.

In particular, the latter two properties are very strong on the surface design of the dryer fabric forming yarns, while the freedom from marking and the high dimensional stability is mitbestimmbar by the cross-sectional shape of the yarns.

Amongst other things, dryer fabrics today consist of spiral structures in which plastic coils are formed from plastic wires and overlap them in this way be stored side by side, that the individual coils are connected by plug wires. The yarns used for such Spiralsiebstrukturen are either round or already provided with a deviating from the round shape cross-sectional shape, which may be flat oval or approximately rectangular, for example.

From WO09 / 130036 A1 a device for producing helices made of plastic wires is known which comprises a winding device which has a rotatable about its axis guide for the wires, and with a shaped body on which the coil can be deposited by means of the winding device and of the it is deductible. The winding device is associated with a rotatable with her deformation device for the cross section of the respective wire. The coils thus produced accordingly have a cross-sectional shape which is selectable and tunable to the desirable properties of a dryer fabric referred to above.

A disadvantage of the plastic helixes produced in this way is that, although a change in the cross-sectional shape of the wire is achieved, but their surface is not changed, especially on a microscopic scale. As a result, the dryer fabrics quickly become dirty and as a result can no longer fulfill their various tasks. Thus, there are deteriorations in the sheet delivery, in the drying efficiency caused by inferior moisture removal and variable moisture cross profile of the fiber web material. The invention is therefore based on the object of specifying an apparatus and a method by means of which the yarns provided for winding up plastic filaments can be influenced not only in their cross-sectional shape but also in their surface structure during the production process. Furthermore, it is an object of the invention to provide a correspondingly shaped and structured yarn and a spiral wire of such a yarn. The object is achieved in terms of the device, the method, the plastic coil and the dryer wire respectively by the characterizing features of the independent claims in conjunction with the generic features.

According to the invention, it is provided that the plastic coils are simultaneously deformed and structured in one step. This can be done by correspondingly shaped rolls in a rolling bearing which, in addition to a suitable shape for cross-sectional deformation of the previously extruded yarn, have a surface configuration which imparts a texture to the yarn surface.

For this purpose, the rollers may have a shape deviating from a cylindrical shape, at least in regions, and / or have a surface structure on their surface, so that the surface of the yarn can be designed as desired in order to obtain the desired property profile.

Further advantageous embodiments and refinements of the invention will become apparent from the dependent claims. It is particularly advantageous if a lateral surface of the rollers at least partially have the shape of single, double or multiple Rotationshyperboloiden, cones or cones. This allows an easy-to-implement mechanical adaptation of existing devices for producing the plastic spiral for spiral wire to.

Advantageously, the surface structures of the rollers may be in the form of strips, ribs, grooves, wavy lines.

Particularly preferably, the strips, ribs, grooves, wavy lines can assume any position between axially parallel to an axis of the rolls and parallel to a circumferential direction of the rolls. According to a further advantageous development of the invention it can be provided that the surface structures are formed in the form of projections of different shapes or recesses of different shapes. Particularly preferably, the surface structures may be distributed uniformly or non-uniformly over the surface of the rolls.

According to a preferred embodiment of the invention, the surface structures may be formed as a macrostructure and / or as a microstructure.

The macrostructure preferably has an order of magnitude of 0.9 mm to 0.9 μm.

The microstructure may have an order of magnitude of 0.9 μιτι to 0.01 μιτι. Advantageously, a depth of the surface structures 0.01 μm to 0.3 mm, preferably 0.01 mm to 0.2 mm.

Preferably, a distance between two adjacent surface structures 0.1 μιτι to 0.9 mm, preferably 0.01 mm to 0.6 mm.

Preferably, roughness in the area of the surface structures should be less than 0.3.

A preferred method for producing plastic coils by winding yarn of plastics into individual coils, which are overlapped on a work surface in the transverse direction and joined together by flat wires to each other, can provide that the coils placed next to each other on the work surface after winding and brought on this work surface by a joining means for engagement and connected by the plug wires each with each other, wherein the coils generated by the at least one winding means and after thermal shaping by a movement of the joining means in addition to a guide rail on the Are stored, the respective subsequent spirals by moving their winding device and this downstream joining device between the guide rail and the previously deposited coil on the work surface are stored, wherein the at least one previously deposited coil by the movement of the joining device transverse to it by a measure of Overlapping be displaced on the work surface, and wherein the last deposited coils are interconnected by at least one inserted peg each other, and wherein the yarn is formed in a rolling bearing, wherein the rolling bearing is formed of at least two rollers with a nip formed therebetween which the yarn is guided and wherein a change of the outer shape and / or the surface of the yarn takes place.

Preferably, the change in the shape of the yarn can be effected by a corresponding shape of the rollers of the rolling bearing.

The change in the surface of the yarn can advantageously be effected by impressing a surface structure, which is at least partially provided on at least one of the rolls, into the yarn. A plastic spiral formed according to the invention for use in dryer fabrics in the dryer section of a machine for producing a fibrous web such as a paper or board web may preferably be produced according to the above method, wherein the yarn forming the plastic spiral has a cross-sectional shape deviating from a round shape and / or the yarn forming the plastic spiral has, at least in sections, a surface structuring.

Preferably, the surface structuring may comprise strips, ribs, grooves, wavy lines, projections of different shapes and / or recesses of different shapes. According to an advantageous aspect of the invention, the strips, ribs, grooves, wavy lines may take any position between parallel to an extending direction of the yarn and parallel to a circumferential direction of the yarn. Advantageously, the surface structures may be distributed uniformly or non-uniformly over the surface of the yarn.

According to an advantageous aspect of the invention, provision may be made for the surface structures to be formed at least partially on an outer side and / or on an inner side of the plastic spiral after the yarn has been laid into the helical form.

The surface of the plastic spiral preferably has a roughness of less than 0.3.

An advantageous spiral wire for use in a machine for producing a fibrous web, such as a paper or board web, comprising a plurality of plastic helices interconnected by plug wires, is preferably characterized in that the plastic helices are at least partially provided with a surface structuring, which positively influence the dirt resistance and the sheet dispensing properties of the spiral screen and thus ensure a consistent quality of the produced fibrous web.

According to a particularly preferred embodiment variant of the invention, plastic filaments with different surface structuring can be combined in irregular or in regular sequences, whereby the sheet dispensing properties can be significantly improved.

It is particularly advantageous that the spiral fabrics of the invention can be used in a variety of positions in the paper machine, so in particular as a forming or drying wire, but also as a basic structure for a press felt. The subject invention and its modes of action and other advantages will be explained in more detail with reference to Figures 1 to 5. In the drawings show:

1 is a fragmentary view of an apparatus for producing spiral isierten plastic helixes according to the prior art,

2 is a highly schematic view of developments according to the invention of the rolling bearing of the device according to FIG. 1, FIG. 3 highly schematic examples of plastic spiral with different surface structures which can be produced by means of the devices according to FIG

Fig. 4 is a highly schematic side view of a single loop of a plastic spiral with embossed surface structures.

In Fig. 1 is a highly schematic view of a section of a device 1 for producing plastic coils for the production of paper machine clothing, in particular of spiral screens for use in the dryer section of a paper or board machine according to the prior art.

Such devices 1 are known per se, so that can be dispensed with a detailed description at this point. The device will be described only in terms of its parts relevant to the invention in order to facilitate the understanding of the inventive measures.

The device 1 comprises a housing 2, in which a rolling bearing 3 is formed. The rolling bearing comprises a first roller 4 and a second roller 5, between which a nip 6 is formed. In the nip 6 an already deformed yarn 7 can be seen, which is originally approximately round Cross-sectional shape, in which it exits, for example, from an extruder not shown, has been converted into an oblong oval cross-sectional shape.

The first roller 4 is adjustably mounted in an adjusting device 8, while the second roller 5 is fixedly mounted in the housing 2. The adjustment of the position and the drive of the first roller 4 are possible via a drive 9, which is arranged in the housing 2 suitable.

The rollers 4 and 5 of the rolling bearing 3 are smooth and cylindrically shaped according to the prior art. A deformation of the yarn 7 is thus carried out only by the approach of the first roller 4 to the second roller 5 by reducing the nip 6 and a corresponding displacement of the still deformable plastic material of the yarn 7 to the outside. The cross-sectionally changed yarn 7 produced in this way thus has a cross-section that is indeed changed, but still has a smooth surface. Accordingly, the above-mentioned properties of the yarn 7 and the dryer fabric produced from the yarn 7 are unsatisfactory in terms of, in particular, the sheet discharge and the dirt resistance.

Remedy can be created in a simple manner by modification of the rollers 4 and 5 of the rolling bearing 3. In Fig. 2 corresponding rollers 4 and 5 are shown with developments of the invention. For the sake of clarity, only the rollers 4 and 5 and the yarn 7 are shown.

On the left in FIG. 2, a combination of a first roller 4 having a double rotationally hyperbolic shape with a second roller 5 cylindrical but provided with a surface structure 10 can be seen. The first roller 4 tells the yarn 7 a macroscopic structure, which in this case generates a groove 1 1 in the yarn longitudinal direction, while the second roller 5 the yarn 7 is provided with a surface structuring 12 which is produced by pressing the surface structure 10 of the roller 5 into the material of the yarn 7.

As a result, a yarn 7 is obtained which has differently configured surface shapes and structures on an upper side and a lower side. Depending on the orientation of the yarn 7 in the later plastic spiral, the channel 11 can point inwards or outwards and have the embossed surface structuring 12 inwards or outwards. FIG. 4 shows, for example, a single loop of a plastic spiral, in whose upper area a surface structuring 12 is visible only on the inside, whereas the yarn 7 can be provided on the outside with the channel 11, for example (not visible in FIG. 4). In Fig. 2 right another embodiment of an inventively designed roller bearing 3 can be seen, in which both rollers 4 and 5 have a double rotationally hyperbolic shape and communicate according to the yarn 7 a shape with grooves 1 1 on the top and on the bottom. Furthermore, the second roller 5 has a surface structure 10, which is formed like shark skin. This produces a corresponding surface structuring 12 on the yarn 7, which has very good properties in terms of dirt and water instruction as well as the flow behavior in air and water flows. Such effects (for example the so-called lotus effect) are known from nature and are used industrially in a variety of ways.

The shape of the rollers 4 and 5 and the design of their surface structures 10 are virtually unlimited. Any combination of single, double or multiple rotational hyperboloids as well as combinations of conical, cylindrical or any other geometries following sections may be used. The surface structures 10 may be in the form of stripes, grooves, wavy lines parallel to the roll axis, inclined or diagonal shape up to the circumferential direction of the rolls of parallel shape. Projections in any shape or recesses of any shape may be distributed uniformly or non-uniformly over the surface of the rolls 4, 5 at least in regions. It is also possible to combine a plurality of surface structures 10 on one of the rolls 4, 5. In addition, it is possible, for example, to combine the rotationally hyperbolic shape with a surface structure 10. The dimensioning of the surface structures 10 can be subdivided into a macrostructure and a microstructure, which can be used individually or in combination with one another. The macrostructure may have an order of magnitude of 0.9 mm to 0.9 μm, while the microstructure has an order of magnitude of 0.9 μm to 0.01 μm.

A depth of the surface structures 10 is 0.01 μιτι to 0.3 mm, preferably 0.01 mm to 0.2 mm. A distance between two adjacent surface structures 10 is 0.1 μm to 0.9 mm, preferably 0.01 mm to 0.6 mm. The roughness in the region of the surface structures 10 is less than 0.3, so that the surface roughness of the yarns 7 is correspondingly less than 0.3.

Suitable limiting elements not shown in the nip 6 may limit the width of the squeezed yarn 7 and produce a nearly rectangular cross-sectional shape. By structuring these boundary elements, the sides of the yarn 7 can also be structured in a targeted manner.

In Fig. 3, for example, a plurality of plastic coil 13, which together form a drying wire 14, shown. The plastic coil 13 are held together in a manner known in principle by plug wires 15. In the first exemplary embodiment on the left in FIG. 3, the plastic filaments 13 are each provided with an impressed groove 11 and a superimposed surface structuring 12. In the second exemplary embodiment in the middle in FIG. 3, the plastic filaments 13 are all provided with a diagonally extending groove-like surface structuring 12.

In the third embodiment in Fig. 3 right a combination of two differently shaped plastic coils 13 is shown, which are always arranged alternately. Such trained spiral screens can be produced in one operation by several Spiralisierungseinheiten are operated with different embossing units.

In Fig. 4, as already mentioned, a single loop of a plastic coil 13 for use in a dryer 14 for a paper or board machine is shown, which in the upper area on its inside and in the lower area on its outer side a surface structuring 12 as described above can have. The different arrangement of the surface structuring 12 can have different effects with regard to the performance of the plastic spiral 13 or, as a consequence, of the drying wire 14. An improved contamination resistance in the interior of the plastic coil 13 leads to more uniform drying performance, since the open volume of the dryer fabric is retained even after prolonged use. External surface structures 12 improve the sheet dispensing properties, in particular when differently structured plastic coils 13 alternate with each other, as shown in Fig. 3 right.

In particular, different structurings may be provided on the outside and on the inside of the plastic spiral 13, by means of which different properties can be achieved. Thus, the insertion of the plug wires 15 can be simplified by a transverse structuring of the inside, while favors the fixation of cored wires by another suitable structuring can be. At the same time, a modification different from the structuring of the inside can be provided on the outside at the same time, for example with the aim of influencing the sheet dispensing properties or reducing the susceptibility to soiling.

The use of the described plastic filaments 13 is possible in almost every papermachine fabric, in particular in dryer fabrics and forming fabrics, but also a use as a basic structure for press felts is conceivable and possible.

The invention is not limited to the illustrated embodiments. In particular, any combination of features are conceivable and possible.

Claims

claims

1 . Apparatus (1) for producing plastic coils (13) for use in spiral screens in a machine for producing a fibrous web, comprising at least two rollers (4, 5), between which an adjustable nip (6) is formed, characterized in that the rollers (4, 5) have an at least partially deviating from a cylindrical shape and / or that the rollers (4, 5) on their surface at least partially have a surface structure (10).

2. Apparatus according to claim 1, characterized in that a lateral surface of the rollers (4, 5) at least partially has the shape of single, double or multiple Rotationshyperboloiden, cones or cones.

3. Apparatus according to claim 1 or 2, characterized in that the

Surface structures (10) of the rollers (4, 5) in the form of strips, ribs, grooves, wavy lines are formed.

4. Apparatus according to claim 3, characterized in that the strips, ribs, grooves, wavy lines arbitrary positions between axially parallel to an axis of the rollers (4, 5) and parallel to a circumferential direction of the rollers (4, 5) can take.

5. Apparatus according to claim 3, characterized in that the

Surface structures (10) are formed in the form of projections of different shapes or recesses of different shapes.

6. Apparatus according to claim 4 or 5, characterized in that the

Surface structures (10) evenly or non-uniformly over the surface of the rollers (4, 5) are distributed.

7. Device according to one of the preceding claims, characterized in that the surface structures (10) are formed as a macrostructure and / or as a microstructure.

8. The device according to claim 7, characterized in that the macrostructure has an order of magnitude of 0.9 mm to 0.9 μιτι.

9. Apparatus according to claim 7, characterized in that the microstructure has a magnitude of 0.9 μιτι to 0.01 μιτι.

10. Device according to one of the preceding claims, characterized in that a depth of the surface structures (10) 0.01 μιτι to 0.3 mm, preferably 0.01 mm to 0.2 mm.

11.Vorrichtung according to any one of the preceding claims, characterized in that a distance between two adjacent surface structures (10) 0.1 μιτι to 0.9 mm, preferably 0.01 mm to 0.6 mm.

12. Device according to one of the preceding claims, characterized in that a roughness in the region of the surface structures (10) is smaller than 0.3.

13. A method for producing plastic coils (13) by winding yarn (7) made of plastics into individual coils which are overlapped on a work surface in the transverse direction and inserted together by wire meshes (15) parallel to each other to form fabrics, wherein the coils after the Winding placed side by side on the work surface and brought on this work surface by a joining device and connected by the plug wires (15) each with each other, the coils generated by the at least one winding device and after thermal shaping by a movement of the joining device next to a guide rail the working surface are stored, the respective subsequent spirals are deposited by movement of their winding device and the subsequent joining device between the guide rail and the previously deposited coil on the work surface, wherein the at least one previously deposited Wen del are moved by the movement of the joining device transversely to her by a degree of overlap on the work surface, and that each last deposited coils by each at least one inserted pintle (15) are interconnected, characterized in that the yarn (7) in a rolling bearing (3) is formed, wherein the rolling bearing (3) of at least two rollers (4, 5) with a nip formed therebetween (6) is formed, through which the yarn (7) is guided and wherein a change of the outer shape and / or the surface of the yarn (7) takes place.

14. The method according to claim 13, characterized in that the

Changing the shape of the yarn (7) by a corresponding shape of the rollers (4, 5) of the rolling bearing (3).

15. The method according to claim 13 or 14, characterized in that the change of the surface of the yarn (7) by impressing on at least one of the rollers (4, 5) provided surface structure in the yarn (7).

16. plastic spiral (13) in particular for use in drying screens (14) in the dryer section of a machine for producing a fibrous web such as a

Paper or board web produced according to the above method, wherein the yarn (7) forming the plastic spiral (13) has a cross-sectional shape deviating from a round shape, characterized in that the yarn (7) forming the plastic spiral (13) is at least in sections a surface structuring (12) and / or has a different shape from a round cross-section.

17. plastic coil according to claim 16, characterized in that the

Surface structuring (12) has strips, ribs, grooves, wavy lines, projections of various shapes and / or recesses of different shapes.

18. plastic coil according to claim 16 or 17, characterized in that the

Stripes, ribs, grooves, wavy lines can take any position between parallel to a direction of extension of the yarn (7) and parallel to a circumferential direction of the yarn (7).

19. Plastic coil according to one of claims 16 to 18, characterized in that the surface structures (12) are distributed uniformly or non-uniformly over the surface of the yarn (7).

20. Plastic filament according to one of claims 16 to 19, characterized in that the surface structures (12) are formed after laying the yarn (7) in the helical shape at least partially on an outer side and / or on an inner side of the plastic coil (13).

21. Plastic spiral according to one of claims 16 to 20, characterized in that a roughness of the surface of the plastic coil (13) is smaller than 0.3.

22. spiral screen (14) for use in a machine for producing a fibrous web such as a paper or board web, comprising a plurality of plastic helixes (13) according to one of the preceding claims, which are interconnected by plug wires (15), characterized in that the plastic helices (13) are at least partially provided with a surface structuring (12).

23. Spiral wire according to claim 22, characterized in that plastic filaments (13) with different surface structures (12) are combined in irregular or in regular sequences.

24. Spiral wire according to claim 22 or 23 for use as a dryer fabric, forming fabric or press felt base.