FI91727B - Process for producing a perforated roller shell for a suction roller in a papermaking machine and means for producing a perforated roller shell for a suction roller in a papermaking machine - Google Patents

Description

91727

A method of making a torn roll casing of a paper machine suction roll, a roll made by the method and a means by which a torn roll casing of a suction roll of a paper machine is made.

The invention relates to a method and means for manufacturing a torn roll jacket of 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 torn roll shell having 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 shell.

20 It is known that torn metal sheaths are made by drilling. Problems with 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 fatigue 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 above-mentioned disadvantages.

Thus, the method according to the invention for manufacturing the torn roll jacket 30 of 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 been applied, leaving holes in the jacket.

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The means according to the invention for producing a torn roll jacket of 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 casing material of the roll is a carbon fiber 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. for a hedgehog mold, the method makes holes in the casing without drilling. Winding or lamination is known per se 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.

15 Because the method winds the fibers of the sheath material, the material being composite, between the pins, the risk of crack growth in the sheath is small because the structural reinforcing fibers are intact and not drilled, as is the case when drilling holes in the sheath. Perforated sheaths have a relatively stronger composite sheath relative to the metal sheath than intact sheaths, which is why the perforated sheath tends to be made of composite. Thanks to the invention, it is thus possible to produce a suction roll with 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 and not necessarily a circle, such as holes obtained by drilling. It can also be e.g. a polygon (e.g. a triangle or a rectangle or an ellipse). Since the hole is always pin-shaped, its shape may 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, the method according to the invention makes it possible to position the holes better 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 solid 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 out or in, 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.

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

15

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

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

20

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 for 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 it around a 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)

91727 Patent claims A method of making a torn roll casing of a paper machine suction roll, comprising placing the casing material by lamination or winding around a mold (12), characterized in that the mold (12) has pins (13) which are removed after curing and / or overlaying the casing material. after leaving holes (15) in the casing. Method according to Claim 1, characterized in that the desired distribution of holes (15) is achieved by arranging the pins (13) accordingly. 10 Method according to Claim 1 or 2, characterized in that the diameter shape of the pins (13) and thus of the holes (15) is a circle or whatever shape is desired. Method according to one of Claims 1 to 3, characterized in that the shape of the holes 15 varies in the depth direction by means of the shape of the pins (13). Method according to one of Claims 1 to 4, characterized in that the pins are mechanically detached from the base body by pulling them out or inwards, melted by heat or dissolved, or if the pins are on a "mat" on the mold (12) after removal. Method according to one of Claims 1 to 5, characterized in that the sheath (11) is produced in part or in whole as a composite sheath, the material of which is a fiber-reinforced polymer. 25 Method according to one of Claims 1 to 6, characterized in that the ratio of holes to solid material is 10 to 95%. Method according to one of Claims 1 to 7, characterized in that the jacket 30 is produced as a layered structure. 91727 Roll made by a method according to one of Claims 1 to 8, characterized in that the jacket material of the roll is a carbon-fiber-reinforced polymer (plastic). Roll according to Claim 9, characterized in that the shape of the holes (15) 5 is a circle or a polygon (triangle, rectangle, etc.) or an ellipse. Roll according to Claim 9 or 10, characterized in that the ratio of holes to solid material is 10 to 95%. Roll according to one of Claims 9 to 11, characterized in that its casing is a layered structure. A means for manufacturing a torn roll jacket (11) of a paper machine suction roll (10), comprising a mold (12) around which the jacket material is wound or laminated, characterized in that the mold (12) is provided with protruding pins (13). Device according to Claim 13, characterized in that the pins (13) can be pulled in or out. Device according to Claim 13 or 14, characterized in that the material of the pins is a polymer or a metal. Device according to one of Claims 13 to 15, characterized in that the pins (13) are on a "mat" on the mold, which mat can be removed after the molded form has been removed. Device according to Claim 13, characterized in that the pins (13) can be melted or dissolved when the material is polymer or wood. Device according to one of Claims 13 to 17, characterized in that the pins cover 10 to 95% of the surface area of the mold. «I 91727 Device according to one of Claims 13 to 18, characterized in that the shape of the pins is desired, e.g. a polygon, a circle or an ellipse. 5,91727