FI87375C - guide roller - Google Patents

Description

The present invention relates to the use of a roll with a rotationally symmetrical roll part with a diameter at the edge region of the material web 5 smaller than in the rest of the material web for a new purpose.

The guide rollers are commonly used in various machines involved in the manufacture or processing of a planar material web, such as a paper web, to control the passage of the material web. In a paper machine, the guide rollers after the paper coating step become dirty at the edges of the paper web because the coating mass is transported with them to the edges of the paper web.

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Today, this problem is solved by not coating the edge area of the paper web to prevent contamination of the guide rollers. This causes several disadvantages. The unpaved area of the paper path has to be discarded. The uncoated area 20 has a lower strength, which easily breaks the paper web. In addition, a tension gradient is created between the uncoated and the coated area, increasing the possibility of track gaps. When using the so-called short-stay coaters are set to the width of the paper web to be coated, the so-called with end dams, which take time to adjust and cause a lot of track breaks. In addition to this, the end dams increase the wear of the rollers. All of the above disadvantages incur additional costs.

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Other currently used solutions are e.g. using scrapers to remove dirt deposits from the rollers or manual cleaning of the guide rollers. The scrapers remove contaminants from the guide rollers that fall onto the paper web, resulting in poor paper quality. Manual cleaning often has to be performed, which incurs additional costs.

2,87375

For example, DE patents 32738 and 374749 and FI patent 50001 disclose the rollers which are the subject of the invention, but they are intended for spreading the track, i.e. for increasing the transverse tension of the track, i.e. their purpose is quite different from that of the present invention.

The object of the present invention is to provide a solution which does not suffer from the above-mentioned disadvantages. The solution according to the invention is characterized in that the rolls according to the preamble 10 are used after the coating step of the paper machine as a guide roll so that the edges of the material web are not in contact with the surface of the roll part.

The solution according to the invention achieves considerable advantages. The roll design prevents the roll from becoming dirty at the edge of the paper path. This makes it possible, for example, to cover the entire width of the paper web, thus reducing the amount of paper to be discarded. In addition, the number of line breaks will be significantly reduced.

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In the following, the invention will be explained in detail by means of preferred exemplary embodiments with reference to the accompanying drawings, in which Figure 1 shows a guide roll according to the invention.

Figure 2 shows some preferred examples of the end design of a guide roll according to the invention.

Figure 3 shows further examples of the design of the end of the guide roll according to the invention.

Figure 1 shows a guide roll 1, the edge areas 2 of the roll part of which are smaller in diameter than the diameter of the area 3 in contact with the material web 4 of the roll part 35, for example the paper web. The difference in diameters should normally be at least about 10 mm. The web of material 4 must be substantially wider than the contact surface of the roll part 1, 3 'r ·? - · r-, - b / O / t; so that the edges of the paper web 4 do not come into contact with the roll. The material web 4 is preferably 10 to 100 mm wider than the area 3 in contact with the material web 4 of the roll part 1. The design of the edge region 2 of the roll is not essential for the detachment of the edge of the paper web 4.

Figures 2A-2D show some preferred examples of implementing the end shaping of the roll part 1. In the pictures, only one end of the roll is shown. In Fig. 2A, a smaller diameter area 2a is arranged at the ends of the guide roll roll portion 10 at the edge region of the material web 4, the surface 3 in contact with the material web of the roll portion 1 being narrower than the material web 4 so that the edges of the material web 4 do not touch the roll surface. In Fig. 2B, a groove 2b is arranged in the roll portion 1 of the wire-15 roll at the edges of the material path 4, whereby the edges of the material path 4 are not in contact with the surface of the roll. In Fig. 2C, the end of the guide roll is formed into a cone 2c, whereby the roll part 1 tapers as a cone towards the roll axis 5. In Fig. 2D, the entire roll part 1 of the guide roll roll is narrower than the material web 4, the edges of the material web 4 not in contact with the roll part 1 surface.

Figure 3 shows further various examples of the implementation of the design of the end of the guide roll 25. According to the figure, the surface 3 in contact with the material path of the roll part 1 tapers in the form of a cone, convex or concave rounding to a smaller diameter edge area 2.

It will be apparent to those skilled in the art that the invention is not limited to the exemplary embodiments set forth above, but may be varied within the scope of the appended claims.

Claims (1)

4 C7: 7 c 0 <j / j CLAIM A roll with a rotationally symmetrical roll portion (1) having a diameter smaller at the edge region (2) 5 of the material web (4) than in the rest of the web of the web (4). after the coating step as a guide roll so that the edges of the material web (4) are not in contact with the surface of the roll part (1). 10 Rollers, which can be rotated with a rotationally symmetrical roll (1), with a diameter of the material (4) 4) contact with the valsdelens (1) yta.