FI86089C - Molding for molding of a molding section with double wire in paper machine - Google Patents

Description

86089

The structure of the strip shoe of the two-wire forming part of a paper machine

List construction for a list of partitions with a double hinge and a paper mask 5

The invention relates to the structure of a strip shoe 1i s of a two-wire forming part of a paper machine.

The invention relates to a list of forming shoes for a two-wire forming part of a paper machine. The strip structure forms a curved guide surface which guides the common curved flow of the web to be formed between the two forming wires. With the aid of the forming shoe and in their region, dewatering of the pulp 15 takes place under the effect of the compression pressure between the wires. Dewatering is further aided by the curvature of the forming shoe, whereby water is removed from the pulp transported between the wires due to the centrifugal force.

From the areas between the moldings of the forming shoe, a vacuum suction is also directed to the wires 20 and further through the wires to the pulp. The vacuum areas are thus located at a location determined by the list spacing and the list width. As it passes the molding of the forming shoe, strong vacuum pulses are produced in the pulp. This pulsation can be optimized for each pulp composition by selecting a molding shoe. 25 the width of the lists is correct.

The strip structure of the molding shoe of the forming part is thus able to influence e.g. paper porosity, paper roughness, and paper absorption. r Thus, it is essential that the strip spacing and 30 strip plates of the forming shoe be varied and that these sizes be optimally selected for each paper machine and pulp cycle.

Thus, when using strip shoes as dewatering elements in the two-wire forming part of a paper machine, it is essential that the strip shoe strips 35 have surfaces so formed that the flow of outgoing water is smooth and dirt accumulation on the strip shoe strip is prevented by all strip widths.

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It is therefore an object of the invention to provide a strip structure of a paper machine forming strip, the surface shape of which is particularly suitable for narrow strip widths and whose strip has outer surfaces so as to achieve smooth dewatering of the pulp without the strip collecting removable water or other removable constituents.

Accordingly, it is an object of the invention to provide such a strip structure which is capable of favorably affecting the filler and fines distribution of the web.

It is a further object of the invention to provide a two-wire web forming shoe strip shoe comprising a strip structure which improves web formation, wherein the strips used to form the wrapper wire wrap forming the forming part allow optimal pressure pulses to be applied to the paper web.

Accordingly, it is an object of the invention to provide a strip structure which can be used to advantageously influence the web formation, taking into account the different speeds and different paper grades of the paper machine. Since a considerable part of the dewatering takes place in the area of the forming shoe, the dewatering event can potentially be influenced by the strip shoe and its moldings according to the invention. Thus, the strip structure of the forming shoe shoe component forms an integral part of the dewatering equipment, and thus it will be appreciated that by optimizing the molding structure, the entire papermaking process can be potentially affected.

In the strip according to the invention, the strip surface facing the movable wire part is relatively narrow. The top of the strip comprises a straight surface which directs the flow of outgoing water falling from above. The narrow list according to the invention does not contain overhead forms which collect water and impurities which are unfavorable for dewatering. According to the invention, the strip structure further comprises lower strip surfaces which run from the surface against the wire part initially approximately horizontally and / or obliquely downwards and further steeply about vertically downwards. These surfaces form a cavity between the wire and the strip shoe, which opens when the strip is attached downwards to the strip shoe. The strip structure of said strip shoe forms advantageous guide surfaces for the outgoing water. The molding structure according to the invention does not comprise underlying dirt or water collecting surface structures. 5 Water is removed through the wire structure of the smoothly moving wire section.

The strip structure of the strip shoe of the paper web forming part of the paper machine according to the invention is mainly characterized in that the lower strip surface has a first surface portion adapted to run approximately horizontally and an associated second surface portion adapted to extend downwards. the angle between the base plane being in the range of 35 ° -80 °, and that the structure has a third curved strip surface between the first surface portion and the second surface portion 15.

The invention will now be described with reference to some preferred embodiments of the invention shown in the figures of the accompanying drawings, to which, however, the invention is not intended to be exclusively limited.

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Fig. 1A shows the web forming part of a paper machine in a schematic schematic representation.

Fig. 1B shows a strip shoe structure of a two-wire forming part of a prior art paper machine.

Figure 2 shows a list according to the invention in axonometric view.

Figure 3 shows an end view according to the invention with the list shoe mounted in place. In connection with the pattern, a moving wire is arranged, which is guided by the surface of the strip shoe.

Figure 4A shows a strip shoe structure formed of strips according to the invention in connection with a two-wire forming part of a paper machine. Figure 4B shows, on an enlarged scale, point A of Figure 4A.

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Figure 5 shows another preferred embodiment of the list according to the invention.

Figure 1A shows a web forming section or former of a paper machine. 5 The pulp is conveyed from the headbox between the wires R1 and R2 to the area of the curved strip shoe 10, where a vacuum is applied between the strip shoe strips to the wire surface and the paper web W to be further formed.

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Fig. 1B shows a partially schematic formation of a curved path by means of the strips 11 of the strip shoe 10a, 10b, 10c. Water is sucked from the area between the slats of the slat shoe through the moving wire from the paper web W. The entire forming part may comprise several slipper shoes 10a, 10b, 10c, whereby changing the position and shape of the slipper shoes affects the radius of curvature and further dewatering properties.

As shown in Fig. 1B, the forming area comprises three strip shoes: strip shoes 10a, 10b and 10c. Each strip shoe comprises a plurality of adjacent strips 11. Water is sucked from the areas 12 between the strips by means of a vacuum and removed through the outlet channels 13a, 13b and 13c. Figure 1B shows a molding structure of a molding shoe according to the prior art. The narrow strip width L of the strip surface coming against the wire part in the prior art structure has been disadvantageous from the point of view of dewatering. Dewatering 25 has been turbulent and contaminants have accumulated in the strip structures in the spaces formed between the strip and the wire.

Figure 2 shows an axonometric view of a strip shoe according to the invention.

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Figure 3 shows the strip according to the invention in an end view and the strip shoe installed in place. The strip shoe strip 11 comprises a guide surface 110 facing the wire R1 and a straight back surface 111 projecting from said surface, and the strip is in place with a lower strip surface 112 forming a downwardly opening cavity 113 between the moving wire Rx and the strip surface 112.

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The straight back surface 111 of the structure allows a smooth outflow of water to be removed from the pulp. It is essential that the back surface is straight and it is preferred that, when the strip is in place, it is adapted to run obliquely downwards so that the wire-side edge of the back surface 111 5 is located at the top. When the lower cavity 113 is formed between the wire and the strip, a smooth outflow of the discharge water is also allowed along the lower surface 112 of the strip. Thus, the new strip according to the invention does not comprise such spaces formed between the wire Rj and the strip structure which would tend to collect impurities and splash water.

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When the strip 11 is mounted on the strip shoe 10, the lower additional surface 112 is formed by a first substantially horizontal surface portion 112a and a second somewhat vertically downwardly extending surface portion 112b. Arrows Lj show the discharge of water through the wire 15 from the paper web W along the strip surfaces 112a and 112b. The strip structure comprises conventional fastening means 114, as shown in the figure, by means of a T-groove, by means of which the strip can be fastened to the counter fasteners 115 of the strip shoe 10.

Figure 4A shows a structure formed from strips according to the invention in a forming shoe of a two-wire forming part of a paper machine.

.. Figure 4B shows, on an enlarged scale, point A of Figure 4A.

In Fig. 4B, the arrows Li show the drainage flow from the web W through the wire »25 R: to the space 116 between the adjacent strip parts 11a and 11b and further out of the space 116. It can be seen in the figure that no space or the like is formed in the intermediate space 116 which would collect impurities.

Fig. 5 shows another embodiment of a strip 11 according to the invention, comprising dovetail fastening means 117 which can be fitted to counter-fastening means, i.e. to the dovetail groove of the strip shoe 10. The lower surface 112 of the strip 11 comprises a surface portion 112b which is at an angle α to the bottom plane E of the fastening means. The angle α is in the range of 35 ° -80 °. Preferably, the lower strip surface 112 comprises a third curved surface portion 112c between the approximately horizontally extending surface portion 112a and the vertical surface portion 112b connecting the surface portions 6 86089 112a and 112b. List 11 is made of ceramic material or the like.

Claims (2)

7 86089 A list structure of a strip shoe (10) of a two-wire forming portion of a paper machine, wherein the strip shoe (10) has a plurality of adjacent strips (11) extending over a wire width 5, and each strip (11) has a guide surface (110) for guiding both forming wires R1 (R2 ) and the web (W) to be formed between them, which is dewatered by and under the action of the compression pressure between the wires R1 (R2) by means of and in the region of the slats (11) of the slat shoe (10). 11) and in which the curvature formed by the strips (11) facilitates dewatering with centrifugal force applied to the paper web (W) to be formed in the area of the curved wire export, and in the strip structure (11) with the strip shoe (10) in place 15 the incoming guide surface (110) and the upper back surface (1) adjacent to that guide surface (110) 11), which is preferably straight and preferably oblique to the horizontal plane, thereby facilitating the drainage of water from the space (116) between two adjacent strips, and the strip (11) has a lower strip surface (112) abutting the guide surface 20 (110) against the wire (Rt), is shaped so that a downwardly opening cavity (113) is formed between the moving wire (Rj) and said strip surface (112), whereby in the strip structure no contaminants accumulate on any surface of the strip and the outgoing water is allowed to flow smoothly along the strip surfaces (11), characterized in that the lower strip surface (112) has a first surface portion (112a) adapted to run approximately horizontally and an associated second surface portion (112b) adapted to run down the strip (11). ) in the forming part with the list window (30) turned (10) in place, the second the angle (α) between the plane of the surface portion (112b) and the bottom plane (E) of the strip fastening means being in the range of 35 ° -80 °, and that the structure has a third curved strip surface (112c) between the first surface portion (112a) and the second surface portion (112b). Structure according to Claim 1, characterized in that the strip (11) is made of a ceramic material or the like. 8 86089