The invention relates to a method according to the preamble of the appended claim 1 in connection with a reel-up. The invention also relates to a device in connection with the reel-up, the device being of the presented in the preamble of the appended claim 8.
By means of a continuous reel-up a continuous paper web, typically of several meters wide, passed from a paper machine or finishing machine for paper, is reeled to form machine reels. To implement the reeling in a continuous manner, a reel change has to be conducted at fixed intervals, so that when the preceding machine reel becomes full, the web is guided to travel to a new reel spool forming the core of the next machine reel.
In the reeling station, when the reel to be reeled becomes full, the web is cut by means of a suitable method which depends e.g. on the grammage of the web, and the new end of the web following the cutting point it guided around a new empty reel spool which has been brought to a change position from a reel spool storage at an earlier stage. There are a number of patents and patent applications related to this change sequence or a part of the same. The Finnish patent 95683 of the applicant, the corresponding international publication WO 93/34495 and U.S. Pat. No. 5,779,183 disclose a press device by means of which the access of air underneath the web entering the reel is prevented. The Finnish patent application 915432 of the applicant, as well as the corresponding U.S. Pat. No. 5,360,179, in turn, disclose different ways of cutting the web in connection with the reel change. The Finnish patent 97339 of the applicant and the corresponding EP application publication 739695 and the U.S. Pat. No. 5,765,462 disclose a blade cutting device that cuts the web. Furthermore, the Finnish patent 100590 of the applicant discloses a manner in which the web can be cut in full-width by means of a striking cutting blade, and the new end of the web can be blown on a new empty reel spool by means of an air blowing.
It is known to move the aforementioned press device in which a brush or a roll functions as a contact member, to a loading contact with a surface of the reel, substantially the lower surface of the reel, in the end phase of the reeling process, and the press device is conveyed in loading contact with the full reel when the reel is transferred to a change position. By means of press devices of prior art it has been possible to prevent the access of air in the reel, and thereby the slackening of the surface layers of the machine reels.
However, especially when the running speeds exceed 25 m/s, problems are caused by the behaviour of the “tail ” remaining topmost in the machine reel after the cutting.
When a brush-like member is used as a contact member in the press device, the bristles of which are in contact with the surface of the machine reel, problems are caused by the insufficient linear load in the contact point. The contact of the brush and the paper produces dust. Furthermore, the dragging force caused by the brush causes a change in the web tension in connection with the reel change.
The press roll used as a contact member keeps the reel well in its form, and it does not produce dust. When the tail meets the press device it is not in contact with the surface of the reel, and it hits the press device thus causing a strong pull in the paper, wherein pieces of paper are torn off. The press roll presses these loose pieces on the surface of the paper reel, and these pieces travel along with the rotating motion of the reel to the upper sector of the reel, wherefrom they may drift in the nip between the new, initiated reel and the reeling cylinder, thereby ending up inside the new reel and causing broke and problems at the next stage of the process, especially in a supercalender or a corresponding multinip calender.
One purpose of the present invention is to introduce a method in connection with the reel change, by means of which the above-presented drawbacks of the solutions of prior art can be eliminated to a large degree, thus improving the state of the art in the field. To attain this purpose, the method according to the invention is primarily characterized in what will be presented in the characterizing part of the appended claim 1. The device according to the invention, in turn, is characterized in what will be presented in the characterizing part of the appended claim 8. The method is characterized in that the reel and/or the tail which is not in contact with the reel or tends to loosen from the same are/is controlled at two distinct points on the perimeter of the reel: control of the outer surface layers of the reel by means of a press roll producing the loading and control of the tail by means of a separate guiding member which applies a smaller load to the reel and whose surface speed differs substantially from the surface speed of the peripheral surface of the reel. The latter member is primarily used for controlling the tail. by guiding it towards the reel and/or by wiping off the pieces detached from the tail before they are conveyed to the upper half of the reel wherefrom they could again end up in the closing reeling nip. The device is characterized by the combination of the press roll of the reel and the guiding member of the tail.
In the following description the invention will be described in more detail with reference to the appended drawings. In the drawings
The guiding member 3a is located within the area of the lower half of the reel and it is used for guiding the travel of the tail H forming the final section of the cut web W. The guiding member 3a is preferably located in the vicinity of the lowest point of the reel, for example in the sector of ±45° therefrom. The press roll 3b is located within a short distance after the guiding member 3a. The distance is such that it is not possible for the tail to substantially loosen itself from the surface of the reel. The distance, when measured along the perimeter of the reel is advantageously approximately smaller than a ¼ of the diameter of the reel, in other words in degrees approximately under 30°.
The free tail H revolves during several laps around the rotation axis of the reel on the perimeter of the reel R along with the rotating motion of the reel during several revolutions, and the guiding member 3a is used for controlling the behaviour of the tail H advantageously during several revolutions after the cutting of the web.
The parallel surface speed of the surface of the guiding member 3a opposite to the reel and of the peripheral surface of the reel differ substantially from each other. Thus, there is a relative speed difference between the peripheral surface of the web and the surface of the guiding member opposite to the same. The speed difference is such that the speed of the surface of the guiding member 3a in the direction of the peripheral surface of the reel is clearly lower than the surface speed of the reel. The speed difference can be attained by arranging the guiding member 3a static, i.e. stationary, as the brush shown in
The surface of the guiding member 3a opposite to the peripheral surface of the reel R is arranged elastic in such a manner that it can be pressed against the surface of the reel within a particular distance, and it can also conform to the variations in the diameter of the reel. Thus, the position of the guiding member 3a with respect to the reel R does not have to be adjusted accurately. To implement the yielding surface, the guiding member 3a may be provided with bristles, but also with other types of flexible members, which wipe the surface layers of the reel R and/or the tail H. The guiding member 3a may be provided with flexible strips or the like, extending in the transverse direction of the machine, i.e. in the direction of the reel axis, forming a sort of a doctor blade. Such flexible members, e.g. bristles, strips or the like guide the loose tail H softly on the surface of the reel, and because of the slower surface speed, release the pieces possibly loosening from the tail in the impact of its end. It is also possible that the static guiding member only has one transverse strip against the perimeter of the reel or in the vicinity of the same, within a particular width lying against the peripheral surface of the reel and/or guiding the tail H.
If the guiding member 3a is a rotating guiding member, its surface can also be formed of bristles, wherein it is a kind of a brush roll wiping the surface of the reel, or of strips transverse to the machine direction, the strips also wiping the surface of the reel, wherein it is a kind of a strip-faced roll.
The surface structure of the guiding member 3a can also be a uniform compressible structure, and it can, for example, be the surface of a sponge-like body.
Another alternative is a contactless guidance, in which the surface of the guiding member 3a is not in contact with the outer surface layer of the compact reel R, but rather in contact with the tail H formed of the final end of the web, thus guiding the tail closer to the web. The distance from the outermost surface layer of the reel is in this case small, advantageously under 10 mm. The guiding member 3a within a small distance from the peripheral surface of the web is also capable of preventing the entrance of the small pieces loosened from the tail between the press roll 3b and the reel R.
The guiding member 3a is most advantageously located before the press roll 3b in the direction of rotation, wherein it first receives the loose tail H coming in the direction of the perimeter of the reel. It is, however, possible that the guiding member 3a is within a short distance from the press roll 3b after the same, wherein it is in a sufficiently fight contact with the surface of the web in such a manner that it is capable of wiping off the pieces of paper passed through the nip between the reel and the press roll 3b from the surface of the reel. The surface structure and the motion (static/rotating) of the guiding member 3a can be arranged according to the description above.
The guiding member 3a can also be a relatively rigid member which is directed against the direction of rotation of the reel and located before the press roll 3b in the direction of the perimeter of the reel, and it is spaced within a short distance (e.g. under 20 mm) from the peripheral surface of the reel, wherein the purpose of the same is to receive and cut the loose end of the tail H which is farther away from the reel than the positioning distance of the member, and to guide the tail preceding the loose end towards the nip between the press roll 3b and the reel R. Such a member can taper off against the direction of rotation of the web, and it can be formed as a sharp-edged cutting blade.
The guiding member 3a and the press roll 3b are advantageously arranged to a common frame 3c to be moved in the machine direction with respect to the reel R and together with the motion of the reel, in either one of the above described orders. Thus, the distance between the press roll 3b and the guiding member 3a can also be arranged to be suitably small in view of their good co-operation. As can be seen in
The guiding member 3a advantageously extends over the entire width of the web. The control member can also extend only over a part of the width of the web for example at points where the tail H is at its longest. Thus, it can be only within an area of particular width on both edges in cases where sections which are especially long remain in the reel on said edges in gooseneck changes or corresponding change methods, in which the web is first torn from the middle. The press roll 3b advantageously extends over the entire width of the reel R.
Number | Date | Country | Kind |
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991450 | Jun 1999 | FI | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/FI00/00501 | 6/6/2000 | WO | 00 | 12/13/2001 |
Publishing Document | Publishing Date | Country | Kind |
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WO01/00515 | 1/4/2001 | WO | A |
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4964587 | Oki et al. | Oct 1990 | A |
5360179 | Vesterinen et al. | Nov 1994 | A |
5765462 | Mannio | Jun 1998 | A |
5779183 | Aalto et al. | Jul 1998 | A |
5895007 | Moller et al. | Apr 1999 | A |
6427938 | Madrzak et al. | Aug 2002 | B1 |