EP1659216A1 - Roll for the production of a web, in particular for the dewatering of pulp - Google Patents

Abstract

The press roller (11), especially for extracting water from a wet tissue web, has a number of outer layers around the core (13). The outermost layer (30) is relatively hard and thin, over a significantly thicker layer (20) which is relatively soft. The two layers are supported by a bottom layer (15) against the roller core. The layers are of rubber, vulcanized together. The outer surface is fitted with recesses (34) and/or blind drillings (32).

Description

The invention relates to a roller, as used for the dewatering of the required for the production of paper, cardboard and pulp slurry of fibers, for example, so-called tissue material from which absorbent and soft kitchen towels or the like. be made or paper-like material such as cardboard. In particular, the roller is designed for use in the wet press of a paper machine. Furthermore, the invention relates to the use of such a roller. The roller in this case has an elastic roller coating, which is advantageous for the dewatering of pulp and the production of paper and cardboard.

Since such types of rolls are usually subject to high line load, there is a narrowing of the possible coating hardening grooved coatings: In order to prevent the unallowable closing (compression) of the grooves under load, depending on the line load relatively hard covers are used, which technologically for optimal drainage often represent an unfavorable solution. Better would be in many paper machines, especially the aforementioned machines for tissue material, relatively soft covers with a hardness in the range 70 to 90 ° Shore A, which lead at a defined line load to advantageous, longer press zones, so-called wider press nips. However, such materials are not sufficiently wear-resistant or, given sufficient wear resistance, are not sufficiently elastic and / or can not be grooved because of the above-described relationships.

Task and solution

The invention has for its object to provide an aforementioned roller, with which the problems of the prior art can be avoided and in particular the dewatering of pulp for tissue material is more effective and gentler for the fiber composite in front of him and the rollers at the same time longer service life to have.

This object is achieved by a roller with the features of claim 1 and a use with the features of claim 13. Advantageous and preferred embodiments of the invention are the subject of further claims and are explained in more detail below. The wording of the claims is incorporated herein by express reference.

According to the invention, it is provided that the roller has several layers or the outer layers of a roller or a type of functional covering of a roll cover are divided into two layers. An outer or outermost layer is relatively hard and wear-resistant. In it, bores and / or recesses may be provided, which are formed in particular for the removal of water from the pressed sheet material. The outer layer is on a relative soft inner layer applied. The inner layer and the outer layer advantageously consist of solid material.

The subject of the invention is thus above all the functional coating, which is divided into an inner softer layer which provides the desirable wider nip and a harder outer layer which offers the higher wear resistance and the possibility of additional grooving. Due to their higher hardness, there is no risk of closing the groove under load. At the same time, this harder layer offers a higher wear resistance compared to the softer inner layer.

The division is independent of partially multilayer, thin bonding layers or interconnecting intermediate layers, which are used, for example, a stable bonding of the coatings to a metal core or the like. to ensure. Here, the high modulus jump between metal and elastic cover gradually "softened" or adapted. Any used binding layers or intermediate layers are not the subject of the invention.

This structure, under which still other layers may be present, makes it possible by the outer hard layer to bring in the wells or grooves well and in a defined degree. The life is increased by the outer layer forming hard and resistant layer, since the hard layer does not wear out so fast. The underlying soft layer largely determines the desired flexibility or resilience of the roller, including the resulting nip. Overall, therefore, a roll which is relatively soft in itself is provided, as corresponds approximately to the inner layer, which, however, has a relatively hard layer on the outer side. Thus, it is well protected against direct wear or tear. The resulting properties can be over the respective Parameters of the individual layers such as material, material hardness and layer thickness are set, which will be discussed in more detail below.

The definitions outer layer and inner layer in connection with this application are intended to mean that the outer layer is the outermost and thus outermost layer. Inner layer means a layer underlying the outer layer. Advantageously, it is directly below, but this does not necessarily have to be the case. Again, very thin intermediate layers could be provided, which, however, do not significantly affect the elastic properties. Thus, the connection of the two layers can be made via suitable, with 20 microns to 1.5 mm very thin intermediate layers, which are applied by brushing or spraying. They can cause elastomeric or direct chemical bridging between the layers.

In an advantageous embodiment of the invention, it is possible that holes or depressions or grooves are provided only in the outer layer. For example, in press rolls, they can reach as far as the underlying inner layer, but advantageously not into it. Thus, it is possible to prevent the grooves closing during compression, in particular when pressed together with high pressures. In suction rolls, the depressions may possibly extend through the outer layer, possibly into the interior of the roll core.

At least the outer layer should advantageously consist of materials based on natural and synthetic rubbers, blends of various rubbers and / or polyurethane. In particular, rubber may be used, preferably solid rubber.

It is of great advantage to also produce the inner layer of an aforementioned material or rubber. Combinations of rubber-based inner layers and polyurethane cover layers as outer layers are also possible.

In order to make the outer layer relatively hard, it may have a hardness of 80 ° to 100 ° Shore A, preferably over 90 ° Shore A, for example 90 ° to 98 °. The relatively soft inner layer may have a hardness of 40 ° to 90 ° Shore A, preferably 60 ° to 85 ° Shore A. As a result, a significant difference in the hardness of the two layers can be achieved, which causes the respective desired properties.

In addition to the different hardness of the layers, the thickness can and should be different. The outer layer should be thinner than the inner layer, for example, have a thickness of 3 to 15mm, advantageously in a range between 5 and 10mm. Although the inner layer should be thicker than the outer, it can be in a range of about 5 to 50 mm, advantageously 10 to 30 mm. This means that the inner layer can generally be about two to five times as thick as the outer one. Of course, the absolute thicknesses are also dependent on the overall diameter of the roller.

For the supporting structure of the roller, a metal core or metal body is advantageously provided, on which the layer structure is applied. In this case, an intermediate layer may be provided between the supporting core and the inner soft layer. This intermediate layer may also be made of rubber. An adaptation of the material properties between hard metal and relatively soft inner layer is particularly advantageously achieved by the intermediate layer when its hardness is higher than that of the soft inner layer. For example, it may be approximately in the range of the hardness of the outer Layer, whereby advantageously the number of required materials for the layer production can be kept low. The intermediate layer may also be thinner than the soft inner layer, since it is intended only for the adaptation of the inner layer to the steel core or steel body, but not for influencing the overall properties of the roll in terms of flexibility or the like.

The layers are applied successively to the roll or core. A rubber material is advantageously vulcanized onto the underlying layer. This makes it possible to create particularly durable bandages, especially in the case of compounds from rubber to rubber as well as to metal.

A roll as described above is particularly advantageously used in the dewatering of the pulps of fibrous material required for the manufacture of paper, board and pulp, preferably tissue, paper pulp or paper-like material. Especially with these soft materials, the flexibility of the roll comes into play, while at the same time increasing wear resistance and improving the quality of the web materials produced. Other applications for such a roller are conceivable, for example in paper, cardboard or the like.

These and other features will become apparent from the claims but also from the description and drawings, wherein the individual features each alone or more in the form of sub-combinations in an embodiment of the invention and in other fields be realized and advantageous and protectable Represent embodiments for which protection is claimed here. The subdivision of the application into individual sections as well as intermediate headings does not restrict the general validity of the statements made thereunder.

Brief description of the drawings

• Fig. 1 einen Schnitt durch eine Walze mit drei Schichten und Bohrungen in der äußeren Schicht und
• Fig. 2 zwei verschiedene Ausbildungen der Oberfläche der äußeren Schicht mit Bohrungen und Rillen.

Embodiments of the invention are shown schematically in the drawings and will be explained in more detail below. In the drawings show:

• 1 shows a section through a roller with three layers and holes in the outer layer and
• Fig. 2 shows two different configurations of the surface of the outer layer with holes and grooves.

Detailed description of the embodiments

In Fig. 1, a roller 11 is shown in section. For example, it can be used in a press shop to produce tissue material, relatively soft paper or even board, for the pulp needed for the production of paper, board and pulp.

On a steel core 13, which may be of any design and having at its ends not shown shaft ends for storage, an intermediate layer 15 is first applied. It has a thickness of several millimeters and is made of solid rubber. On the intermediate layer 15, the inner layer 20 is applied by vulcanization. It has a thickness of about 15mm. On the inner layer 20, in turn, the outer layer 30 is vulcanized with a thickness of about 5mm. Instead of rubber could be used as a material here also polyurethane.

In the embodiment, all layers 15, 20 and 30 are made of solid rubber. The hardnesses of the intermediate layer 15 and the outer Layer 30 is at about 95 ° shore A. The hardness of the soft inner layer 20 is about 70 ° Shore A.

It can be seen that the outer layer 30 bores 32 and grooves 34 has. Although these extend to the intermediate layer 20, but do not penetrate into this.

In the plan view of the roller 11 of FIG. 2 can be seen how the distributed holes 32 and grooves 34 may look like. Of course, other distributions are possible here, for example, only holes or grooves only partially. However, a structuring of the bores 32 or grooves 34 that is uniform over the entire surface of the roller 11 is preferred. The bores may have a diameter of 1 to 6 mm. Blind holes can be 4 to 200 mm deep. The grooves may have a width of 0.4 to 2 mm and be 1 to 5 mm deep. The web width can be 1 to 4 mm.

When using such a roller 11 for the production of, for example, tissue material, on the one hand, the advantages of a rather soft and flexible roller are available, in particular because of the aforementioned wider nip due to the resilience of the overall covering of the roller 11. This is especially true for the soft and relatively bulky or thick tissue material advantageous. On the other hand, is limited by the outer layer 30 of the resulting wear. The important during operation holes 32 and grooves 34 are thereby better defined or predictable that they are introduced into the outer hard layer 30.

Claims (13)

Roller (11) for dewatering the slurry of fibrous materials, preferably paper stock or paper-like material, required for the production of paper, board and pulp, the roller (11) having a plurality of layers (15, 20, 30), wherein a relative soft inner layer (20) is a relatively hard and wear-resistant outer layer (30) is applied, wherein the inner layer (20) and the outer layer (30) made of solid material without air pockets. Roller according to claim 1, characterized in that the outer layer (30) has bores (32) and / or recesses (34), preferably with a diameter of 1 to 6 mm and / or blind holes of a depth of 4 to 20 mm. Roller according to claim 2, characterized in that the depressions in the form of grooves (34) are present, preferably obliquely to the direction of passage of the web material, in particular the grooves (34) are 0.4 to 2 mm wide and / or 1 to 5 mm deep are, preferably a web width is 1 to 4 mm. Roller according to claim 2 or 3, characterized in that the inner layer (20) is free of bores (32) and / or depressions, wherein depressions in the form of grooves (34) preferably pass completely through the outer layer (30). Roll according to one of the preceding claims, characterized in that at least the outer layer (30) consists of a material of the following group: rubber, rubber, polyurethane, preferably of solid rubber, in particular the inner Layer (20) consists of the same material as the outer layer (30). Roller according to one of the preceding claims, characterized in that the outer layer (30) has a hardness of 80 ° to 100 ° Shore A, in particular from 90 ° to 98 ° Shore A. Roller according to one of the preceding claims, characterized in that the inner layer (20) has a hardness of 40 ° to 90 ° Shore A, preferably from 60 ° to 85 ° Shore A. Roller according to one of the preceding claims, characterized in that the outer layer (30) has a thickness of 2 to 20 mm, preferably from 5 to 10 mm. Roller according to one of the preceding claims, characterized in that the inner layer (20) has a thickness of 5 to 50 mm, preferably 10 to 20 mm. Roller according to one of the preceding claims, characterized by an inner metal core (13) or metal body, which carries the layer structure, wherein preferably between the core (13) and inner layer (20) an intermediate layer (15) is provided, which consists in particular of rubber. Roller according to claim 10, characterized in that the intermediate layer (15) has a Shore hardness higher than that of the inner layer (20), wherein preferably the intermediate layer is thinner than the inner layer. Roller according to one of the preceding claims, characterized in that the layers (15, 20, 30) are vulcanized together. Use of a roller (11) according to any one of the preceding claims in the manufacture of thin web material, preferably tissue material, paper stock or paper-like material, preferably in the dewatering of the pulp slurry needed for the manufacture of paper, board and pulp.

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