This application is a U.S. national stage application of Internatinal Application No. PCT/FI01/00852, field Oct. 1, 2001, and claims priority on Finnish Application No. 20002166 filed Oct. 2, 2000, the disclosures of both of which applications are incorporated by reference herein.
Not applicable.
The present invention relates to equipment for cutting particularly a paper web with a water jet, which equipment includes support and positioning means and a cutting head supported on them extending in the operating position to the edge part of the paper web, in which there is a support surface arranged at least beneath the edge part and, above it, at least one nozzle for forming a cutting jet with the aid of high-pressure water, which nozzle is set in such a way that the edge part travels between the support surface and the nozzle, in order to cut an edge strip from the paper web.
Finnish publication print number 98346 discloses equipment for cutting the edge of a paper web. In this case, for the actual cutting, the equipment includes a nozzle for forming a cutting jet with the aid of high-pressure water, and a surface arranged beneath the nozzle. In the cutting situation, the paper web travels between the nozzle and the surface, so that the water jet cuts the paper web. There is a hole in the surface for the cutting jet and, at this point beneath the surface, there are outlet connections for removing the cutting water from the equipment. The surface is also termed a table, the location of which together with the nozzle can be adjusted in the cross direction of the paper web.
Despite the hole in the surface and blasts of air direction towards the cutting point and the outlet connections, a lump of paper fibers and fillers accumulates very quickly on the surface after the cutting point. The problem appears particularly when cutting paper grades with a high filler content. The problem is the same, both in the above and in other known equipment. In principle, the equipment is designed in such a way that the paper web is only just separated from the surface by an air cushion. In practice, either the edge strip that has just been cut, or even the entire paper web can touch or catch on the lump, which usually results in a web break. The lump also interferes with the creation of the air cushion. The surface can be manually cleaned during a maintenance shutdown, but when the equipment is operating, the surface cannot be kept clean by means of the known art, despite the air blasts. Reliably operating cutting would, however, be a precondition for successful continuous paper production.
The invention is intended to create an entirely new type of equipment for cutting particularly a paper web with a water jet, which equipment can be easily kept clean, and on which detrimental lumps do not form. The equipment according to the invention includes many different alternatives for keeping the equipment clean and thus for preventing the formation of a lump. Different constructions can be selected for specific cases and it is also easy to combine the constructions. In this way, troublefree cutting is ensured, thus improving the efficiency of the entire paper production.
In the following, the invention is examined in detail with reference to the accompanying drawings showing certain embodiments of the invention.
a shows a front view of the equipment according to the invention.
b shows a side view of the equipment of
a and 2b show a side and top view of a first embodiment of the cutting head of the equipment according to the invention.
a and 3b show a side and top view in partial cross-section of a second embodiment of the cutting head of the equipment according to the invention.
a, 4b, and 4c show top views of a third, fourth, and fifth embodiments of the cutting head of the equipment according to the invention
a, 5b, and 5c show a front and side view in partial cross-section of a sixth and seventh embodiment of the cutting head of the equipment according to the invention,
a and 6b show a side and top view of an eighth embodiment of the cutting head of the equipment according to the invention.
a and 7b show a side view of a ninth and tenth embodiment of the cutting head of the equipment according to the invention.
a, 8b, and 8c show a side and top view in partial cross-section of an eleventh and twelfth embodiment of the cutting head of the equipment according to the invention,
a and 9b show a side and top view in partial cross-section of a thirteenth embodiment of the cutting head of the equipment according to the invention.
a and 1b show a front and side view of the equipment according to the invention. In this case, the equipment includes support and positioning means 10, which comprise a support arm 11 and a guide construction 12 adapted to it. The support arm 11 is attached to a suitable point in the paper machine, usually to both sides of the paper web. The equipment is usually located at the end of the paper machine, near the reeler. In addition to a paper machine, the equipment can also be used in conjunction with board machines and similar, for cutting even a thick web. In
In the cutting head 13, there is a support surface 16 arranged at least beneath the edge part 14′ and above it at least one nozzle 17 for forming a cutting jet with the aid of high-pressure water. The cutting head 13 is arranged in such a way that the edge part 14′ travels between the support surface 16 and the nozzle 17, so that an edge strip 18 is cut from the paper web 14. In addition, in the cutting head 13 there are connections 19 and 19′ for removing the cutting water and the edge strip 18 from the equipment. Part of the cutting waste is also removed along with the cutting water.
The invention relates to the cutting head 13 of the equipment and particularly to keeping the support surface 16 clean, so that disturbances caused by cutting are avoided. According to the invention, there are two main ways of keeping the support surface clean. The first is the active cleaning of the support surface and the second is the passive prevention of the dirtying of the support surface. For this purpose, the equipment includes mechanical cleaning means 20 and/or a cleaning construction 21 for keeping the support surface 16 clean. In the following, various alternative applications are presented, which realize at least one of the invention's objectives.
In order to implement the first objective, mechanical cleaning means 20 are arranged in connection with the equipment and/or the support surface 16, to clean the support surface. In addition, the cleaning means are arranged to operate continuously or at intervals. The construction of the support surface greatly affects the choice of the manner of operation of the cleaning means.
It is possible to manufacture a general model of the cleaning means, which is suitable for all support surfaces. Such cleaning means 20 are arranged in the equipment, outside the edge part 14′ of the paper web 14, in which case the support surface 16 is arranged to be cleaned by moving the cutting head 13 with the aid of the support and positioning means 10 to the location of the cleaning means 20. The cleaning means 20 located outside the edge part 14′ are shown in
a and 2b show a support surface 16, which is formed of a nearly conventional level table 22. However, precisely the part 22′ of the support surface 16 after the cutting point is arranged to be able to be moved laterally in the working position of the cutting head. The relevant part 22′ forms a slide, which moves in a guide groove 23 machined in the support surface 16. By moving the slide laterally, the dirt collects over a larger area, so that a detrimental lump is not able to form. In addition, cleaning means 20 are arranged in connection with the support surface 16. Thus, the surface of the slide can also be cleaned outside the edge area, for example, by means of a mechanical scraper 24 (
Besides the linear movability described above, the entire support surface or part of it is arranged to rotate around its vertical axis. Correspondingly, the cleaning means 20 are outside the edge part of the paper web.
Continuous cutting can be implemented by means of a variation of the embodiment described above, which is shown in
c also shows a solution based on rotation. In this case, the table 22 comprises four round components 29, which are rotated together or separately. Thus, the dirt collects evenly on the surface of the components 29. By rotating the entire table 22, the parts beneath the paper web 14 can be moved outside it, so that it is also possible to clean them. In addition, the rotational movement of each component can also be exploited in cleaning. The rotation or cleaning of the components does not affect the cutting itself, which takes place at the point of the opening 26″ delimited by the components 29.
In addition to a flat surface, a curved surface can also be used as the support surface according to the invention. In that case, the support surface is arranged to be rotatable around its horizontal axis. In the following, three such embodiments are examined.
a and 5b show front and sides view of the embodiment. In this case, the support surface 16 is formed by two rollers 30 and 31, which are supported rotatably on the same axle 42. Between the rollers 30 and 31, there is a suitable gap 27, in which the cutting can be carried out. Beneath the rollers 30 and 31, there is also a trough 32, in which the cutting water is collected. The surface of the rollers 30 and 31 can also be easily cleaned, for example, with a mechanical scraper 24.
c shows a variation of the above embodiment. In it, the rollers 30 and 31 are specially shaped at their opposite ends. Thus, they can be placed as close as possible to each other, when it is possible to use a small gap 27. In addition, by leading a water pipe 33 inside the chamber 34 thus formed, the chamber 34 can also be kept clean.
a and 6b also show a curved support surface 16, however, this is not rotated, but moved backwards and forwards. For this purpose, the support surface 16 is supported on suitable support arms 35. The operating device is not shown. The support surface 16 is formed of two components 43, between which a suitable gap 27 is left. During cutting, fibers and filler can also adhere to the components 43, so it is preferable to clean the components 43 by means of a mechanical scraper 24 beneath the paper web 14. A suitable trough (not shown) is also used beneath the support surface 16 described above.
In addition to support surfaces arranged to rotate in relation to a horizontal or vertical axis, it is possible to use a fabric loop 36 as the support surface, as shown in
In
The various embodiment described above are for cleaning the support surface. According to the invention, the support surface can also be kept clean by preventing it from becoming dirty. Generally, this is achieved by forming a cut 38 in the support surface 16 after the cutting point formed by the water jet, in the direction of travel of the paper web 14. At its simplest, this can be implemented in the manner shown in
The cut 38 can also be enlarged, without this significantly disturbing the travel of the paper web.
The equipment according to the invention operates reliably while the support surface remains clean. In addition, the arrangement of the equipment can be made suitable for different operating situations. The cleaning effect can be easily increased by combining features of different embodiments in a single set of equipment. The cleaning means or constructions of the equipment according to the invention are arranged on the opposite side of the paper web to the nozzle, in connection with the support surface. In that case, the cleaning is ensured by means of mechanical cleaning means, without the movement of the paper web being disturbed by it. When the support surface remains clean, the probability of a web break, for example, is significantly reduced.
Number | Date | Country | Kind |
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20002166 | Oct 2000 | FI | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/FI01/00852 | 10/1/2001 | WO | 00 | 7/28/2003 |
Publishing Document | Publishing Date | Country | Kind |
---|---|---|---|
WO02/28605 | 4/11/2002 | WO | A |
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0 886 055 | Dec 1998 | EP |
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Number | Date | Country | |
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20040011175 A1 | Jan 2004 | US |