Arrangement and method for web feeding in a fiber web machine

Abstract

Arrangement for web guiding in a fiber web machine, comprising guide ropes (11, 12) arranged laterally to the web path as a rope guide, as well as first guide means (14) for detaching a guide strip (15) from a cylinder (10) and second guide means (16) for inserting the guide strip (15) between the guide ropes (11, 12), wherein a support element (17) for stabilizing the movement of the guide strip (15) is arranged on the path of the guide strip (15) detached from the cylinder (10) in front of the second guide means (16), characterized in that the support element (17) is located between a straight line (22) defined by a release point (20) of the guide strip (15) and a holding point (21) of the second guide means (16) and the guide strip (15) above the guide strip (15) and below the said straight line (22). is arranged.

Description

[0001] The invention relates to an arrangement for web feeding in a fiber web machine, comprising feeding ropes designed as rope guides laterally to the web's running path, as well as first feeding means for detaching the feeding strip from a cylinder and second feeding means for inserting the feeding strip between the feeding ropes. The invention also relates to a method to be used for web feeding in a fiber web machine.

[0002] A generic arrangement and a generic procedure are known from DE 10 2004 037 437 A1.

[0003] This describes another device for transferring a paper web.

[0004] Guide ropes are still used at certain points during web feeding in fiber web machines. Such points include sections where the web runs unsupported, i.e., without any support. In a successful web feeding process, the guide strip is first fed into the rope shear, where the ropes converge and the guide strip is clamped between them. The guide ropes run at the production speed of the fiber web machine and transport the guide strip through the machine to the next stopping point, such as a roller nip. The guide strip is inserted between the ropes using a suitable guide device, preceded by a guide device for releasing the guide strip from a cylinder. In other words, first come the initial guide devices for releasing the guide strip, and then the secondary guide devices for advancing the guide strip.An arrangement for web feeding is described, for example, in EP 1 431 454 A1. In the fiber web machine, the feeding ropes are typically located next to the fiber web at a certain distance from the web edge. The feeding strip cut from the web must be fed into a feeding strip separator and, with the aid of any subsequent web feeding devices, guided obliquely laterally towards the rope shear. Web feeding is considered oblique if the angle between the feeding device and the machine direction is more than five degrees.

[0005] In known arrangements, unstable, i.e., erratic, behavior of the feed strip proved problematic. In practice, the feed strip, once detached from the cylinder, hovers in an undefined manner on or above the web feed elements. This situation was particularly problematic with inclined web feeds, where the feed strip's direction of travel changes. In such cases, the feed strip could potentially fall off the web feed elements, requiring the web feed to be restarted from the beginning. This hovering also made it difficult for the feed strip to engage with the wire cutter. The consequences of this indeterminacy in web feed were extended production downtimes and a lengthy duration even for successful web feeds.

[0006] The object of this invention is to provide a novel arrangement for web feeding in fiber web machines, which is of simple construction and avoids the problems previously caused by the floating of the feed strip. Furthermore, the invention is intended to provide a novel method for web feeding in a fiber web machine, with which web feeding is more reliable than before. The characterizing features of this arrangement according to the invention are that a support element for stabilizing the movement of the feed strip is arranged on the path of the feed strip detached from the cylinder, upstream of the second feeding means. Similarly, the characterizing features of the method according to the invention are that the movement of the feed strip detached from the cylinder is stabilized by a support element.The setup functions reliably and can be easily adapted to different positions with minor modifications to ensure successful web feeding. The method can be widely applied to various fiber web machines without significant modifications. The end result is a significantly higher probability of successful web feeding than before. The feed strip is constantly under control, thus eliminating the delays previously caused by the undefined floating of the feed strip. Simultaneously, web feeding can be further automated, since the feed strip's path and travel time are now known more precisely than before.

[0007] The invention is described in detail below with reference to the accompanying drawings, which illustrate some embodiments of the invention. The drawings show: Fig. 1 the arrangement according to the invention viewed from above; Fig. 2 the arrangement according to the invention viewed from the side; Fig. 3 the functioning of the arrangement according to the invention; Fig. 4 an alternative way of arranging Fig. 3.

[0008] Fig. Figure 1 shows the principle of the arrangement according to the invention, designed for web feeding in a fiber web machine. Fiber web machines include, for example, paper and board machines, in which production begins with the help of the web feeder strip. In practice, the feeder strip is fed through the fiber web machine and then spread out to form a full-width web. Fig. Figure 1 shows only one position of the fiber web machine in which the arrangement according to the invention can be used. Several corresponding positions may be present in the fiber web machine. Here, the previously cut feed strip arrives on a cylinder 10 in the position shown.

[0009] This is an arrangement for guiding the web in a fiber web machine, and this arrangement includes guide ropes 11 and 12 designed as rope guides laterally to the web path. Fig. Figure 1 shows only a portion of the feed ropes 11 and 12, which meet on the pulley 13 to form a rope shear. Behind the rope shear, the feed ropes 11 and 12 run side by side, forming a rope guide. The rope guide is arranged so that the feed strip end, inserted into the rope shear, is transported further between the ropes. The arrangement also includes first feed devices 14 for detaching the feed strip 15 from the cylinder 10. This detachment is usually achieved by blowing. The first feed devices 14 also include feed blowing devices, which transport the feed strip towards the second feed devices. The second feed devices 16 bring the feed strip 15, detached from the cylinder, between the feed ropes 11 and 12, more precisely into the rope shear formed by the ropes 11 and 12.In the example shown here, the feed strip is inserted obliquely, with the angle α enclosed by the conveying direction of the second web feeder 16 and the machine direction being approximately 12°.

[0010] According to the invention, a support element 17 is arranged on the path of the feed strip 15, which has been detached from the cylinder 10, upstream of the second feed means 16, to stabilize the movement of the feed strip 15. According to the invention, the feed strip rests on this support element very soon after detaching from the cylinder. While the second feed means transport the feed strip further, the support element causes the feed strip to tighten rapidly. This prevents the feed strip from floating or fluttering, and the feed strip moves stably on the second feed means towards the wire cutter. Preferably, the second feed means 16 consist of one or more vacuum belt conveyors, which are easy and precise to control and also function at high production speeds. In slower machines, for example, one or more feed plates with conveying blow devices can be used.The speed of the vacuum conveyor belt does not need to be precisely determined. In practice, significantly excessive speeds are often used, which tightens the guide strip but causes the belt to slip relative to the guide strip. An alternative and equally effective solution is the use of guide plates.

[0011] In the illustrated embodiments, the support element 17 consists of a non-rotating rod 18 that runs essentially transversely to the guide strip 15. In practice, a smooth, cylindrical metal rod can be used, over whose surface the guide strip slides. The rod can also be made of a different material and coated if necessary. For example, a polished stainless steel rod is suitable as a support element. The rod can also be replaced, for example, by a tube or a curved guide surface. A thin rod takes up little space and does not collect dirt on its surface. The rod also does not impede the release of the guide strip from the cylinder. Several rods can also be used, which together form the support element according to the invention.

[0012] The in Fig. The feed strip 15, arriving on the surface of cylinder 10, is initially guided downwards into the pulper (not shown). As the web feeding continues from this point, the feed strip 15 is detached from the surface of cylinder 10 by the first web feeding devices 14, and simultaneously, the feed strip is generally cut in a controlled manner. The resulting end of the feed strip is guided towards the second web feeding devices 16. Thanks to the support element, the feed strip is quickly stabilized in its movement during tensioning. The rod 18 is therefore arranged transversely to the second feeding devices 16. The direction of movement defined by the rod corresponds to the transport direction of the second feeding devices, so that the feed strip naturally moves directly towards the wire cutter.

[0013] In Fig. Figure 2 shows the arrangement according to the invention viewed from the side. The continuous line shows the path of the feed strip 15 in the situation where the feed strip 15 has already been transported to the second feed elements 16 and has stabilized. In other words, the feed strip is taut. In this situation, the blowing devices of the first feed elements are already switched off, and the second feed elements 16 continue to transport the feed strip 15. Without the support element according to the invention, the feed strip would flutter unsupported and only become taut against the paper guide roller 19 when it has been brought by the cable guide to the next holding point (not shown). As a result of the fluttering, the feed strip could fall off the second feed elements, and its entry into or contact with the cable shear would also be uncertain.Generally speaking, the support element 17 is arranged between the line 22 formed by the release point 20 of the guide strip 15 and a holding point 21 of the second guide means 16, and the guide strip 15. The said line 22 is in . Fig. 2 is represented by a two-dotted line. This placement allows the initial feed mechanisms to operate normally, but results in a rapid, almost instantaneous stabilization of the feed strip. This prevents the feed strip from fluttering and ensures it runs precisely into the rope cutter. Consequently, the time required for feed is significantly reduced, and the probability of successful feed is substantially increased.

[0014] In the inventive method, the feed strip 15 is detached from the cylinder 10 and then, in the exemplary embodiment, transported obliquely by the feed ropes 11 and 12 located laterally alongside the track of the web. According to the invention, the feed strip 15, detached from the cylinder 10, is stabilized in its movement by the support element 17. At the same time, the feed strip tightens. The feed strip 15 is thus fed to the feed ropes 11 and 12, more precisely to the rope shear, in its taut state. This completely new and surprising mode of operation accelerates and improves web feeding, but also necessitates new measures. In practice, to prevent tearing of the feed strip, it is desirable to operate the feeding devices and the rope guides at essentially the same speed.Since, according to the invention, the guide strip is already taut when inserted into the rope cutter, problems can arise when the guide strip encounters the rope pulley. The flanges of the rope pulley, which has a rope groove, are located further out than the ropes, so the peripheral speed of the flanges is greater than the rope speed. In other words, the peripheral speed of the rope pulley is greater than the speed of the guide strip, which can cause the taut guide strip to tear. Previously, this problem did not exist because the fluttering guide strip had a great deal of "looseness," which later disappeared through gradual tightening.

[0015] The arrangement according to the invention also solves this unexpectedly encountered problem. According to the invention, the support element 17 has movement means 23 for adjusting the position of the support element during the web feed. These movement means can consist of joints, guides, or the like. The movement has several different effects, but in one embodiment, the movement means 23 are arranged such that the travel path of the feed strip 15 is shortened by 25–150 mm, preferably by 75–125 mm. In the embodiment described in Fig. In the situation shown in Figure 2, the path d is 25–150 mm, preferably 75–125 mm, shorter than the path D. Furthermore, the shortening is timed so that it occurs at the moment the feed strip enters the rope shear. The artificial loosening achieved by this movement compensates for the jerk of the rope pulley, and the feed strip enters the rope guide without tearing. The required length is short for two reasons: First, when the feed strip moves at production speed, it is only in the rope shear for a moment; and second, thanks to the support element, the feed strip tightens immediately, so that the point of entry of the feed strip is precisely known. Thus, the movement of the support element can be incorporated into the feed sequence, making the feed automatic.

[0016] When creating slack by repositioning the support element, care must be taken to ensure that the set angle is maintained so that the guide strip runs in the desired direction. Fig. 3 and Fig. Figure 4 shows the effect of the support element 17 on the travel path of the guide strip 15. Thus, in the arrangement according to the invention, both the formation of looseness and the effect of the support element on the lateral displacement of the guide strip are taken into account when setting up the movement mechanisms of the support element. Fig. The support element 17 is supported on the first feed elements 14. If necessary, the support element can also be pivoted relative to the machine direction. Such a pivoting has a significant effect on the direction of movement of the feed strip behind the support element.

[0017] With the arrangement according to the invention, the feed strip is inserted into the cable guide in a taut state. If necessary, side walls are inserted into the second feed devices to prevent the feed strip from unintentionally falling off. The support element is preferably located as close as possible to the cylinder to ensure rapid tautness of the feed strip. This also minimizes the amount of feed strip that runs past the feed cables. With correct positioning of the support element, the feed strip runs smoothly and without swaying or pendulum-like motion towards the second feed devices and directly to the optimal feed line. Preferably, the support element and the other feed devices are brought to rest further away from the rotating machine elements for the duration of production. This prevents foreign substances from adhering to the feed devices and avoids any potential web breaks or clumping that could damage them.

[0018] During track laying, there are various phases that occur instantaneously in practice, i.e., very quickly. A so-called double tail can also form on the laying strip. Usually, after detaching and cutting, the laying strip leaves the cable guide. The cut laying strip is fed into the cable guide, and after a selected time has elapsed, the second laying devices are swung in the direction of the machine ( Fig. 1) In other words, the insertion of the guide strip into the rope shear is completed, and the guide strip leaves the rope guide. In known arrangements, the individual phases are undefined, and the guide strip wanders about, which can result in the guide strip falling off the rope guide in an uncontrolled manner. The stabilizing element according to the invention stabilizes the guide strip and prevents it from wandering.

[0019] The arrangement according to the invention functions in both paper and cardboard machines. The natural change of direction caused by the support element and the geometry of the entire arrangement is particularly advantageous in cardboard production, as stiff cardboard only allows for small changes in direction. The support element can easily be retrofitted as part of the feeder system. The rapid tightening and stabilization of the feeder strip caused by the support element accelerates web feeding, and the amount of feeder strip supplied to the feeder ropes can be determined more precisely than before.

Claims

[1] Arrangement for web guiding in a fiber web machine, comprising guide ropes (11, 12) arranged laterally to the running path of a web as a rope guide, as well as first guide means (14) for detaching a guide strip (15) from a cylinder (10) and second guide means (16) for inserting the guide strip (15) between the guide ropes (11, 12), wherein a support element (17) for stabilizing the movement of the guide strip (15) is arranged on the running path of the guide strip (15) detached from the cylinder (10) in front of the second guide means (16), characterized by , that the support element (17) is arranged between a straight line (22) defined by a release point (20) of the guide strip (15) and a holding point (21) of the second guide means (16) and the guide strip (15) above the guide strip (15) and below the said straight line (22). [2] Arrangement according to claim 1, characterized by, that the support element (17) includes means of movement (23) for changing the position of the support element (17) during the execution of the path. [3] Arrangement according to claim 2, characterized by , that the support element (17) consists of a non-rotating rod (18) which is arranged substantially transversely to the guide strip (15). [4] Arrangement according to claim 3, characterized by , that the rod (18) is arranged transversely to the second support means (16). [5] Arrangement according to any one of claims 1 to 4, characterized by , that the second delivery means (16) consist of one or more vacuum belt conveyors. [6] Arrangement at least according to claim 2, characterized by , that the means of movement (23) are arranged such that the running path of the guide strip (15) is shortened by 25 - 150 mm, preferably by 75 - 125 mm. [7] Method for web feeding in a fiber web machine, in which a feed strip (15) is detached from a cylinder (10) and brought to feed ropes (11, 12) arranged laterally along a running path of a fiber web, wherein the movement of the feed strip (15) detached from the cylinder (10) is stabilized by a support element (17), characterized by , that the support element (17) is arranged between the straight line (22) defined by a release point (20) of the guide strip (15) and a holding point (21) of the second guide means (16) and the guide strip (15) above the guide strip (15) and below the said straight line (22). [8] Method according to claim 7, characterized by , that the feed strip (15) is fed to the feed ropes (11, 12) in a taut state. [9] Method according to claim 7 or 8, characterized by that in the process an arrangement according to one of claims 1 to 6 is used.

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