FI91727C - Process for producing a perforated roll sheath for a suction roll in a paper machine and means for producing a perforated roll sheath for a suction roll in a paper machine - Google Patents

Description

91727

A method of making a perforated roll jacket for a paper machine suction roll, a roll made by the method, and a means for making a perforated roll jacket for a paper machine suction roll. en pappersmaskin 10

The invention relates to a method and means for producing a perforated roll jacket for a suction roll of a paper machine and to a roll made by the method. The method uses a mold around which the sheath material is wound or laminated.

15 Paper machines use suction rollers to remove water from the paper webs. Such may comprise a perforated roll jacket with a suction space inside which is generally subjected to a vacuum, whereby the suction flow passes through the perforation of the roll inside the roll and the paper web is pressed towards the outer surface of the roll jacket.

20 Previously known perforated metal sheaths are made by drilling. Problems with the suction rollers have been that the jacket is exposed to corrosion, causing it to crack and the material to break, which means that the material has poor foam strength and fatigue fracture. For example, if the sheath is made of a composite, the fibers will break as a result of drilling, causing the strength value to decrease.

The object of the present invention is to provide suction rollers which do not have the aforementioned disadvantages.

Thus, the method according to the invention for manufacturing a perforated roll jacket 30 for a suction roll of a paper machine is mainly characterized in that the mold has pins which are removed after the jacket material has hardened and / or overlaid, leaving holes in the jacket.

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The device according to the invention for producing a perforated roll shell for a suction roll of a paper machine is again mainly characterized in that the mold is provided with protruding pins.

The roll according to the invention is characterized in that the roll material of the roll is made of a carbon fiber-5-jet polymer (plastic).

Preferred embodiments of the invention have the features of the subclaims.

Since the casing of the suction roll according to the invention is manufactured by winding or laminating 10 around a mold with pins, i.e. the so-called for a hedgehog mold, the method provides holes in the casing without drilling. Winding or lamination per se is already known and the method is described, for example, in DE 3,527,912.

The advantage of such a sheath over a drilled metal sheath is, among other things, that it is light.

Since the method winds the fibers of the sheath material, the material being a composite, between the pins, the risk of crack growth in the sheath is small because the structural reinforcing fibers are intact and not broken, as is the case when drilling holes in the sheath. With perforated sheaths, the composite sheath is relatively stronger than with a metal sheath than with intact sheaths, which is why the perforated sheath tends to be made of composite. Thus, the invention makes it possible to produce a suction roll having a jacket made of a composite material when prior art jackets had to be made of metal due to drilling.

In addition, thanks to the invention, the hole pattern can be changed and the shape of the hole can be any or all of a necessary circle, such as holes obtained by drilling. It can also be, for example, a polygon (e.g. a triangle or a rectangle or an ellipse). Since the hole is always pin-shaped, its shape can also be desired in the depth direction.

The sheath may be partially or completely composite. It can also be made into a so-called sandwich structure.

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In addition, with the method according to the invention, the holes are better positioned in terms of the effect of the suction roll, whereas in the prior art methods this was often done at the expense of the strength values. The ratio of holes to intact material can also be made better for the effect of the suction roll than with previous diapers. In the suction roll according to the invention, the ratio of holes to intact material can be 10-95%. In previously known suction rolls, the open area was 20-75%.

Once the sheath material has been laminated or wound around the mold, the pins can be mechanically removed from the base body by pulling in or out, melted or dissolved, or if the pins are on a "mat" on top of the mold, the entire mat and pins are removed from the inside of the mold.

In the following, the invention will be explained by means of a figure, which is not intended to limit the invention.

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Figure 1A shows a cross-section of a device according to the invention.

Fig. 1B is a longitudinal view of a means according to the invention for manufacturing a roll shell.

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Reference numeral 1 generally denotes a device according to the invention with which a roll jacket is manufactured. It has protruding pins 13 which are of the desired shape and the desired number of such are arranged in a suitable manner on the surface of the mold 1 in terms of the suction effect. As explained above, the roll jacket material is brought in a manner known per se, as disclosed, for example, in patent application DE 3 527 912 A1, by winding or laminating around the mold 12. The sheath material is preferably a composite made of fibers, whereby the fibers are pre-wound between the pins, whereby the finished roll sheath will contain only intact fibers. In particular, carbon fiber and epoxy resin are suitable fibrous materials for the sheath made in the invention. The roll shell can be made partially or completely composite and can also be made in different layers.

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After winding or lamination is completed, the material is allowed to cool, if necessary, after which the pins can be removed from the jacket in the above-mentioned ways.

The claims are set out below.

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Claims (19)

A method of producing a perforated roll sheath for a suction roll of a paper machine, wherein the sheath material is brought by lamination or by winding around a mold (12), characterized in that the mold (12) has pins (13) which are closed after the sheath material hardened and / or after it was applied, leaving the holes (15) in the mantein. 2. A method according to claim 1, characterized in that the desired hole distribution (15) is achieved by positioning the pins (13) thereafter. 3. A method according to claim 1 or 2, characterized in that the shape of the diameters of the pins (13) and thus the holes (15) is a circle or any shape. 15 4. A method according to any one of claims 1-3, characterized in that the shape of the holes varies in depth with the aid of the design of the pins (13). 5. A method according to any one of claims 1-4, characterized in that the pins are released from the basic body by pulling them out mechanically outwards or inwards, melting them down with heat or Idsa up them or if the pins are in a "mat" on top of the mold. (12), the entire carpet is covered with tabs from the inside after unloading the mold. 6. A process according to any one of claims 1-5, characterized in that mante (11) is produced partially or wholly into a composite sheath, the material of which is a fiber-reinforced polymer. 7. A method according to any one of claims 1-6, characterized in that the ratio between holes and whole blank is 10-95%. IN; 91727 8. A method according to any one of claims 1-7, characterized in that manteins are produced as a layer structure. 9. A roller made by a method according to any one of claims 1-8, characterized in that the shell material of the roller is made of carbon fiber reinforced polymer (plastic). 10. A roller according to claim 9, characterized in that the shape of the holes (15) is a circle or multi-hammer (three-hammer, four-hammer, etc.) or an ellipse. 11. Roll according to claim 9 or 10, characterized in that the ratio between the holes and the whole blank is 10-95%. 12. A roller according to any one of claims 9-11, characterized in that its jacket is a layer construction. 15 13. A means for making a perforated roll sheath (11) of a suction roll (10), comprising a mold (12) around which the sheath material is wound or laminated, characterized in that the mold (12) has projecting pins (13). 14. A device according to claim 13, characterized in that the pins (13) can be pulled inwards or outwards. 15. A device according to claim 13 or 14, characterized in that the material on the pins is polymer or metal. 25 A device according to any one of claims 13-15, characterized in that the pins (13) are on a "mat" on top of the mold, which mat can be unloaded with pins after the release of the mold. A device according to claim 13, characterized in that when the material on the pins (13) is made of polymer or plastic, they can be melted down or dissolved. 91727 A device according to any one of claims 13-17, characterized in that the pins cover 10-95% of the surface of the mold. 19. A device according to any one of claims 13-18, characterized therein, that the shape of the tappet is desired, e.g. a plurality, circle or ellipse.