The invention relates to a method in sequential winding stations, which method is presented in the preambles of the appended claims 1 and 7. The invention also relates to a production line comprising sequential winding stations.
The production of paper from pulp to finished paper may be composed of several sequential winding and unwinding stages in which the continuous paper web passed from the preceding processing stage is reeled around a reel spool to form a machine reel, and this machine reel is unwound again at the unwinding stage to pass the paper web to the next processing stage. A typical example is a so-called off-line production of coated paper grades, in which in the paper production line i.e. in the paper machine a continuous web of several meters in length is produced from fibrous pulp, which web is reeled in the reel-up in the terminal end of the paper machine to form a machine reel. Several reel-ups have been presented in the patent literature, and reference can be made for example to the European patents 483092, 483093 and to the international patent publication WO 95/34495. In such winding stations a continuous web passed from the preceding sections of the machine is reeled around a reeling axle i.e. a reel spool, which is a roll of several meters in width, dimensioned with respect to the size of the reel in a suitable way and supported in the winding station by its ends with a suitable supporting structure. The winding stations operate continuously, wherein a new reel spool is brought to the reeling station without reducing the speed of the preceding machine, and the paper web is guided around a new reel spool by using change methods for which numerous patented solutions have been developed. Similarly, patented solutions have been developed for the ways of arranging a loading (linear load) between the reeling cylinder guiding the web and the reel.
In the unwind, the machine reel reeled in the preceding stage is unwound, and a winding station of this type is presented for example in the Finnish patent 100323 and in the corresponding U.S. Pat. No. 5,709,355. The unwind of a coater presented herein operates continuously, wherein a new machine reel which is brought to the unwind is joined at full speed to the paper web of a machine reel that is becoming empty, by means of a splicing device. The unwind is used in the beginning of off-machine coaters to lead the web wound up in the preceding winding station from the successive reels to the coating process. The preceding winding station can be a so-called rereeler in which the reel reeled in the reel-up of a paper machine is unwound and wound up to form a reel which is suitable for the finishing process.
In the end of the off-machine coater there is again a reel-up in which the paper web passed from the coater is reeled around the reel spool again to form a machine reel.
In order to implement the continuous operation, the change of the reels in the reel-up and in the unwind should proceed without problems, and these functions are the most critical stages in the continuous winding up or unwinding. Because of this, it would be advantageous to produce machine reels as large as possible to reduce the number of changes. This is restricted by the heavy weight (several tens of tonnes, in wide machines typically over 50 tonnes) of the reel, and the existing constructions which are dimensioned for particular maximum diameters of the machine reel.
Heretofore, attention has been paid to single winding processes (winding up, unwinding) and their problems.
Conventionally, in lines producing coated paper grades, for example in an LWC-paper line provided with a separate coater, machine reels of equal size are reeled in the reel-up of the paper machine and thereafter in each reel-up process in accordance with the requirements set for the customer rolls of the slitter-winder.
Especially in lines producing coated paper grades, as for example the above-mentioned LWC line, it is difficult to modernize the winding stations in such a way that the diameter of the reel is increase throughout the entire line, because in that case all the reel-up unwinds, cranes, reel spools (nearly 100 by number) and storage rail arrangements have to be modernized. Similarly, inside a factory the lifting height might restrict the growth of the diameter at some points. Thus, when compared to the attained advantages, it is not lucrative to increase the diameters of the reels, even if new winding station constructions provided the possibility for this.
The purpose of the invention is to eliminate the aforementioned drawbacks and to present a new reeling concept in a production line comprising sequential winding stations. To attain this purpose, the method is primarily characterized in what will be presented in the characterizing part of the appended claim 1.
The invention utilizes the short circulations of the reel spools between the reeling-up and unwinding stages. Thus, the reel spools in the production line are dimensioned to be different in size, and it is possible to use a different size in each circulation. Similarly, it is possible to dimension the winding stations for reel spools of different sizes, and for maximum diameters of the reel. Heretofore, it has been natural to use reel spools of equal size in the entire production line, wherein they can be utilized anywhere.
The invention is also characterized by the facts stated in the characterizing part of the appended claim 7. By reeling larger quantities of paper in the first reel-up than in the second reel-up, which is located at some point after the first reel-up in the production line, it is possible to reduce the number of changes in the beginning of the line.
The invention enables a suitable modernizing solution for the winding stations in the production line, by means of which a greater advantage is achieved with smaller investments. Thus, it is only necessary to modernize the winding stations in the beginning of the line, such as the reel-up of the paper machine and the rereeler and the unwind of the coater for paper for the part of the maximum diameter, and possibly the winding stations therebetween. In addition, new, bigger reel spools (20 to 30 by number) are required in this interval as well as a possible additional capacity of one crane. Between the paper machine and the coater for paper the circulation of the reel spools functions completely independently, i.e. the new rolls remain only within this interval.
Similarly in lines where coated grades are produced with on-line coating in a paper machine, it is possible to modernize the reel-up of the paper machine and arrange new reel spools at least in the area between the reel-up and the rereeler.
In the following, the invention will be described in more detail with reference to the appended drawings, in which
In the paper machine, the rereeler and the finishing machine a full-width web is processed, the width of the web corresponding substantially to the production width of the paper machine. This web is divided into narrower webs in the slitter-winder after the unwinding to form customer rolls of particular width.
In
In the paper machine, machine reels are reeled from the paper web passed from the production process, the weight of the reels being typically over 10 tons, depending on the amount of full-width paper web to be reeled.
A separate circulation of the reel spools is arranged between the reel-up KR1 of the paper machine and the unwind AR of the finishing machine for paper, and it is illustrated with arrows TK1. From the unwind AR of the paper finishing machine JK, the reel spools are returned to the reel-up KR1 of the paper machine PK, wherefrom they travel inside the machine reels back to the unwinder AR. Because this first part of the paper production line has a separate circulation of the reel spools, the reel spools can be different, and they advantageously have a larger diameter than the reel spools employed in the terminal end. In the terminal end, i.e. between the reel-up KR2 of the finishig machine JK for paper and the unwinding device AL following thereafter, there is a separate circulation TK2 of the reel spools.
Similarly, the winding stations KR1, VR and AR preceding the finishing machine JK for paper can be dimensioned for larger machine reels, which contain advantageously at least a double amount of paper when compared to the machine reels formed in the reel-up KR2 after the finishing machine JK for paper. This reduces the number of changes conducted in the terminal end of the paper machine PK and in the beginning of the finishing machine JK for paper. Thus it is also possible to attain more running time between the changes, and thereby more capacity in the rereeler VR.
In lines whose principle complies with
In
Furthermore,
The new reel spools can have a diameter which is at least 25%, advantageously at least 35% larger than the diameter of the old reel spools. As an example of a suitable dimensioning of the new and old reel spools and machine reels, it is possible to present the following values, which do not restrict the invention:
The invention is not restricted solely to the alternatives presented above, but it can be modified within the scope of the inventive idea presented in the claims. In
It is also apparent that, irrespective of the size of the reel spools, larger reels are reeled in the winding station located at an earlier position in the line (the first reel-up) than with a winding station located later in the line (the second reel-up). Thus, the advantage is attained that in the beginning, before the second reel-up, there are fewer reel changes in some reeling up process and at least in the unwinding process following this reeling up process. The reel spools in the line can also be equal in size, provided that they are suitable for the larger reel size. Larger reels, preferably at least with a double amount of paper, can be used for transferring the paper between the reel-up KR1 of the paper machine and the unwind AR of the finishing machine. It is also possible that larger reels, preferably with a double amount of paper, are reeled not earlier than in the reel-up of the rereeler VR and unwound in the following unwind AR of the finishing machine JK, for example in the unwind of the coater for paper PPK or in the unwind of the supercalender SC, the reels to be reeled in the second reel-up in the terminal end thereof being again smaller (the reel-up in the coater PPK for paper or in the supercalender SC). Thus, it is possible to arrange the circulation of larger reel spools only between the reel-up of the rereeler VR and the unwind AR of the finishing Machine JK, if it is necessary to use larger reel spools for larger reels.
The present invention has been described herein with reference to preferred embodiments of the invention however the description provided herein is for illustrative purposes and should not be considered to be exhaustive. It is understood that modifications and variations of the above describe preferred embodiments are possible without departing from the spirit or scope of the present invention.
Number | Date | Country | Kind |
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981825 | Aug 1998 | FI | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/FI99/00701 | 8/26/1999 | WO | 00 | 2/26/2001 |
Publishing Document | Publishing Date | Country | Kind |
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WO00/12418 | 3/9/2000 | WO | A |
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