Not applicable.
The present invention relates to a set changing device of a slitter-winder, comprising a pusher device for pushing completed wound fiber web rolls of partial webs cut with a slitter-winder and carried by carrier rolls forward from the winding-up section.
By means of the slitter-winder, the fiber web is cut in the longitudinal direction into parallel partial webs, which partial webs are wound on the winding-up section carried by the front and rear carrier rolls into successive rolls, that is, a set in the transverse direction of the fiber web. As a carrier roll may also be used a belt arrangement provided around two leading rolls, that is, a so-called set of belt rolls. Set change refers to a stage in roll manufacture at which, before starting new winding, the winding has to be stopped, the web cut at the winding-up section and the set, that is, the completed wound partial web rolls removed, and once new cores have been positioned in the winding-up section, the winding of a new set is started.
A problem with the winding-up sections known from the prior art is the reliable fastening of the tail of the partial web rolls being wound, that is, of each fiber web roll being completed. For fastening the tail of a fiber web roll being completed, that is, the tail end of a web being wound, has been used a method in which glue stripes are applied on the web before the winding-up nip and the glue stripes have been run almost completely inside the roll through the winding-up nip before stopping the winding-up section. The fiber web roll is in contact with both the rear carrier roll and the front carrier roll (or the set of belt rolls), whereby the glue is pressed fast in the winding-up nip between the rear carrier roll and the fiber web roll being formed. This causes a problem to the glue stripe that has passed through the nip at the stage when the completed fiber web rolls are pushed out of the winding-up section, because the glued web may open from the roll. With certain web grades, especially heavy grades such as board webs, an opening web causes splitting in the glue stripe area, that is, the glue no longer gives in but the surface layer of the web detaches with the glue instead of the glue stripe opening within the glued area. The split glue stripe will no longer adhere and the gluing thus remains incomplete for this part. The insufficient fastening of the web end may cause the tail to open partly or completely, which in turn causes problems in measurements and in the transport and further processing of the fiber web roll. A completely opened tail will cause problems in a high-rise store house of rolls, where rolls are kept in a vertical position in stacks of several rolls. On the other hand, when winding thin fiber web rolls, a problem may be caused by the pressing action of the nip, due to which the glue may be pressed through several web layers. Another known method is one where the set is lifted off the rear roll and following the cutting of the web, the set is swivelled on the front roll in such a way that the tails are pressed fast on the nip of the roll pusher. The problem with this method is that it takes up extra time and thus reduces the capacity of the cutter.
To solve this problem, a working solution as such is described in Metso Paper, Inc.'s earlier Finnish patent publication FI118762.
A problem with this solution is that the mass of the set is received by one row of press rolls in the pusher 17, which means that the tip of the pusher unavoidably becomes relatively thick in order for it to withstand the mass of the set. This results on the one hand in the roll 10 possibly escaping from the carrier rolls 11, 18 before the row of press rolls on the pusher presses the tail fast against the fiber web roll 10. Pressing the tail fast requires that the lowering device 19 is realized as an uphill-type device, for example, as an uphill tipper, where the pressing fast of the tail can be continued. In connection with new machines this is relatively easy to carry out, but in modernizations the conversion of the lowering device 19 into an uphill-type one substantially increases the cost of the product improvement. Furthermore, a single row of press rolls has been noted to mark the surface of the fiber web roll.
The aim of the present invention is to provide a solution by means of which the disadvantages of the prior art set changing device are avoided and the modernization work can be done at a reasonable cost.
To achieve this aim, the set changing device according to the invention is characterized in that the pusher device comprises at least two press rolls and that the position of at least one of the press rolls with respect to the body of the pusher device is arranged to change during pushing. The pusher device preferably comprises two rows of press rolls formed into a bogie structure (i.e., a wheel truck) in such a way that the rows of press rolls are in contact with the fiber web roll at the same time as the fiber web roll is being pushed at least partly out of the winding-up section.
One of the advantages of the solution according to the invention is that the bogie structure is designed so as to divide the mass of the set between two rows of press rolls, of which the front row of press rolls carries less mass so that it may be designed to be smaller than the rear one. This makes it possible to bring the front row of press rolls further forward, whereby the tail of the roll can be pressed fast before the highest point of the front carrier roll. This reduces the extent of modernization, thus reducing costs.
According to a preferred embodiment of the invention, the set changing device comprises a means which changes the length of travel of the web, which varies the length of travel of the web depending on the lateral point on the web. The means changing the length of travel is, for example, curved in design so that the cutting of the fiber web can be made to start from the center and to proceed towards the edges, whereby the force exerted by the cutting on the cutting blade is reduced. The means changing the length of travel may also be conical or comprised of segments. In connection with this means may in addition be provided means for switching the said means on/off. This type of arrangement is also applicable to other types of set changing devices in addition to the one according to the invention.
The invention is described in greater detail in the following, with reference to the accompanying drawings, in which:
The bogie may be arranged to be turned by an actuator or, for example, by a spring. The bogie may be arranged to turn as synchronized by the pushout motion of the fiber web roll. The bogie may be arranged to turn by contact externally of the pusher device, for example, an end stopper may be arranged in the end position and turn the bogie. In the bogie may be constructed with damping and/or spring elements to affect its turning motion.
The front row of press rolls is preferably curved, so that the cutting of the fiber web is made to start, for example, on the edges and to proceed towards the center or to start in the center and to proceed towards the edges, whereby the force exerted by cutting on the cutting blade decreases. In this way is achieved a means for changing the length of travel of the web, which may also be conical or partly conical/curved or be comprised of, for example, segments. This arrangement is also applicable to set changing devices where the pusher device only comprises one press roll. The means for changing the length of travel of the web may also be implemented as a separate means which can be positioned, for example, in the vicinity of the press roll of a pusher device, or it may be modified from a means by which small rolls are also removed. The means may comprise a device for switching it on/off, for example, pushing means.
Number | Date | Country | Kind |
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20096228 | Nov 2009 | FI | national |
This application is a U.S. national stage application of International App. No. PCT/FI2010/050896, filed Nov. 5, 2010, the disclosure of which is incorporated by reference herein and claims priority on Finnish App. No. 20096228, filed Nov. 23, 2009.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/FI10/50896 | 11/5/2010 | WO | 00 | 5/22/2012 |