FI124111B - Arrangement in the drying section of a fiber web machine for cutting fiber web and the corresponding device and method - Google Patents

Description

APPARATUS WITH A DRYING PART OF A FIBER MACHINE FOR CUTTING THE FIBER AND A SIMILAR DEVICE AND METHOD

The invention relates to an arrangement with a drying section 5 of a fiber web machine for cutting a fibrous web, wherein the moving fibrous web formed by the fibrous web machine is continuously supported by rolls or fabrics belonging to the drying section of the fibrous web machine. The invention also relates to a device and method for cutting a fibrous web.

In current fiber web machines, the so-called single-wire export is often used, in which the fiber web is supported by a wire or roll along the drying section of the entire fiber web machine. In order to facilitate head entry 15 and to avoid damage due to web breakage, the drying section has a plurality of points where the fibrous web can be cut in a controlled manner and fed into a basement or pulper. Generally, at such locations, blowing tubes are used to cut the fibrous web, blowing air from the side 20 of the fibrous web toward the fibrous web, thereby causing tears in the fibrous web. As a result of the ruptures, the fibrous web breaks and can be directed to the basement or pulper in a controlled manner.

However, the problem with using blowing tubes is that the blown air does not provide sufficient time to efficiently cut fibrous webs with a higher basis weight.

There is a problem with board machines, and in particular with wide fiber web machines, with fine paper grades which are naturally cm V tough. Blows effectively cut only one cm 30 to two meters from the edge of the fiber web. In this case, the fibrous web is not severed properly by the use of blowing tubes, but crumpled in the middle of the fibrous web machine, especially with wide fibrous web machines.

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2 Fibrous webs that are crumpled in the middle can cause large deposits

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35 and and wires.

damaging, for example, the suction box of the drying section,

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It is generally known in the art to cut a fibrous web with various blades. However, such cutting is not suitable for a continuous web supported by webs or rolls, since the blades can damage the wire. It is also known in the art 5 to cut a fibrous web using a water jet, but in many applications there is no room for such a solution.

It is an object of the invention to provide a prior art solution 10 and a more efficient arrangement for cutting a fibrous web. It is also an object of the invention to provide a more efficient device for cutting a fibrous web than prior art solutions. Characteristic features of the device 15 of the present invention are apparent from the appended claim 8. It is also an object of the invention to provide a more efficient method for cutting the fibrous web than prior art solutions. Characteristic features of the process of the present invention are apparent from the appended claim 10.

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The object of the arrangement according to the invention can be achieved by an arrangement with a drying section of the fiber web machine for cutting the fibrous web, in which the moving fibrous web formed by the fibrous web machine is continuously supported by fabrics or rolls. The arrangement

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1- includes cutting means for cutting a supported fibrous web o

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, a controlled point and a cutting means are fitted

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V to cause at least a portion of the fibrous web to break at least momentarily the fibrous web by friction to break the fibrous web x £ 30. With such an arrangement, the fibrous web can be effectively cut without damaging the co tissue behind the web.

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Preferably, the cutting means includes an elastic surface 35 to provide sufficient friction for cutting the fibrous web. The elastic surface reduces the contact on the tissue and is sufficiently durable to provide the necessary friction.

Preferably, the cutting means comprises one or more cutting rolls 5 adapted to be pressed against the fibrous web to cut the fibrous web. The cutting roll is simple and inexpensive to manufacture.

The cutting roll may be freely rotatable. In this case, it slows down the flow of the fibrous web at its moment of inertia. In other words, the cutting roll is idle.

Preferably, the cutting roll includes a brake for adjusting the rotational resistance of the cutting roll. In this way, the degree of retardation caused by the cutting roll to the fibrous web and the rotation of the cutting roll after contact can be controlled.

Preferably, the cutting means are adapted to cut the fibrous web against the tissue. Thus, cutting is also suitable for fiber web machines using single-wire feed 20.

According to one embodiment, the arrangement includes blowing means in connection with cutting means. With the aid of blowing means, the operation of the cutting means can be made more efficient.

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1- The purpose of the device according to the invention can be achieved illegally

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, with tea to cut off the fibrous web,

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With a weft section in which the movable fibrous web formed by the fiber web machine is continuously supported by x 30 fabrics or rolls belonging to the drying section of the fiber web machine. The device includes cutting means o for cutting the supported fibrous web in a controlled manner, the co cd lotka cutting means being adapted to cause at least a portion

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slowing contact to cut the fibrous web. With such 35 devices, the fibrous web can be cut in a controlled and efficient manner without damaging the tissue.

o the fibrous web by at least a momentary fibrous web by means of friction

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Preferably, the cutting means comprises a freely rotating cutting roll and a brake for adjusting the rotational resistance of the cutting roll. Such cutting means are advantageously implemented.

The object of the method according to the invention can be achieved by a method for cutting a fibrous web by a dryer section of a fibrous machine, wherein the movable fibrous web formed by the fibrous machine is continuously supported by a cloth or roll belonging to the drying section of the fibrous machine. In the method, at least a portion of the fibrous web is contacted by friction, at least momentarily, to retard the movement of the fibrous web to cut the fibrous web, and the fibrous web is cut against the fabric. With such a method, the fibrous web is cut in a controlled and efficient manner without damaging the tissue. The method is also suitable for use with single-wire twisted fiber webs.

The contact may last for 0.3 to 3.0 seconds, preferably 0.5 to 1.0 for 20 seconds. Due to the short contact, the fibrous web can be cut without the fibrous web accumulating on the cutting roll.

The invention will now be described in detail with reference to the accompanying drawings, in which:

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, Figures la - Ib show a principle view of a fiber web machine and

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Fig. 2a shows an arrangement of the fiber according to the invention

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£ 30 seen from the side of a printing press when the cutting tools are off the fibrous web,

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cd Fig. 2b is an axonometric view of the position of Fig. 2a.

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δ in watts,

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Figure 3a is a side view of an arrangement according to the invention in a fiber web machine when the cutting means contacts the fiber web;

Figure 3b is an axonometric view of the situation of Figure 3a,

Figure 4a is a side view of an arrangement according to the invention in a fiber web machine when the cutting webs have been in contact with the fiber web and the truncated fiber web is guided to a pulper,

Figure 4b is an axonometric view of the situation of Figure 4a.

According to Figure 1a, the invention relates to drying sections 102 of fiber web machines 100, and in particular to a single wire export drying section illustrated in Figure Ib. Fig. Ib shows one drying section of the drying section and its tissue cycle, which rotates endlessly over the entire drying section 104 in question, carrying 15 parts of the fibrous web. Preferably, the upper rolls 24 are drying cylinders, and the lower rollers 26 are preferably under-pressure pivoting rolls that hold the fibrous web in the fabric 14.

2a and 2b, the arrangement 10 according to the invention is located on a drying section of a fibrous web machine, wherein the fibrous web 12 is supported in the group by means of a web 14. The drying group 104 is then preferably a so-called single-wire threading group in which the same fabric twist 33 rotates with the fibrous web 12 both over the upper drying cylinders 24 and the lower turning rolls 26. The cutting means 16 ^ of the arrangement according to the invention can be arranged so that they are close to the fiber web 12 and can be momentarily displaced therefrom on the fiber web 12.

In the embodiment of Figures 2a to 4b, the cutting means 16 are disposed

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£ 30 tu in connection with the pivoting roll 26 of the selected cut-off point 18 (Fig. 1a). The selected cleavage site 18 is one of such

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cd encounters, for example, a drying section with a front or a post-drying section, where the truncated fiber web 12 can be led directly to a pulper in the basement C 1 or otherwise to the basement.

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2a, the cutting means 16 are spaced from the fibrous web 12 as the fibrous web 12 moves supported on the fabric 14 and rotates the pivot roll 26. With said pivot roll 26, the fabric 14 is against the surface of the pivot roll 26 and the fibrous web 12 is over the fabric 14. In this embodiment, the lower dryer roll 26 is preferably a suction roll, for example a VAC suction roll, which holds the nonwoven web 12 in the fabric 14. The fabric 14 preferably refers to a wire cloth which is arranged by rolls in a fabric twist 33. In this step, the cutting means 16 do not rotate.

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3a and 3b, if it is desired to cut the fibrous web 12, the cutting means 16 are moved towards the fibrous web 12 until the cutting means 16 make contact with the surface of the fibrous web 12. The cutting means 16 exert a force on the fibrous web 12 which presses the fibrous web 12 against the fabric 14. During contact of the cutting means 16, a frictional force opposite to the direction of travel of the fibrous web 12 is generated between the cutting means 16 and the fibrous web 12 and the fibrous web 12, which slows the passage of the fibrous web 12 at the cutting means 16. The retardation of the movement of the fibrous web 12 at the cut-off means 16 causes an internal force on the fibrous web 12 that exceeds the tensile strength of the fibrous web. Thus, the cutting means 16 causes the fibrous web 12 to have either a full-width rupture or, alternatively, a hole depending on the width of the cutting means 16 and their position relative to the fibrous web 12. ci and 4b when a hole is made in the fibrous web 12.

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With the help of the cutting means 16, the cutting means 16 are immediately removed from the surface of the fibrous web 12. While the x £ 30 tumbling means 16 create a hole in the fibrous web 12, they release the fibrous web 12 from the surface of the fabric 14. This is how the fiber web 12

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the cd runs in a controlled manner to the pulper.

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In the method according to the invention, the cutting means cause contact with the surface of the fibrous web only for a very short time. The contact duration is only about 0.3 to 3.0 seconds, preferably 0.5 to 7 to 1.0 seconds. Thus, the cutting means causes a tear or hole in the fibrous web, after which the cutting means is detached from the surface of the fibrous web. The release is made so that the fibrous web can be cut without the fibrous web piling on the cutting means 5.

Preferably, the cutting means used in the arrangement and apparatus of the invention are coated with an elastic material. The elastic material allows sufficient friction-10 action between the cutting means and the fibrous web to provide the fibrous web with a retarding frictional force. In addition, the elastic material allows for a softer and more flexible contact with the surface of the fibrous web, which protects the tissue supporting the fibrous web. As used herein, for example, elastic material means a rubber or the like material which is flexible and has a sufficient coefficient of friction. Preferably, the cutting is performed against a dry roll or similar roll, with the fabric and the fibrous web resting on the roll surface. Alternatively, the cleavage may also be performed at an unsupported interval of the tissue, if it is possible to position the cleavage means at the site in question.

2a to 4b, the cutting means 16 is preferably a cutting roll 20 which is pressed against the fibrous web 12. Preferably, the cutting roll 20 is freely rotatable, whereby its surface

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very quickly reaches a tangential velocity corresponding to the velocity of the fibrous web and the tissue. The cutting roll will come

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V may be such that its momentum is sufficient to exert a retarding force on the fibrous web. This effect can be

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£ 30 is enhanced by installing a brake on the cutting roller to adjust the rotation resistance of the cutting roll o. In addition, the brake can be applied

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co whenever the cutting roll is removed from the surface of the fibrous web. to hide

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o The rotation of the roller roller should be stopped, or at least substantially

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slows down before the next contact with the fibrous web to provide sufficient retardant force of the fibrous web 35.

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For example, the cutting roll may be mounted on articulated arms 28, as in Figures 2a to 4b, or the cutting roll may be movably linearly guided towards and away from the fibrous web. The arms can be moved, for example, by means of a cylinder-5 actuator. The diameter of the cutting roll may be, for example, 100 to 500 mm, preferably 200 mm. For example, the cutting roll may have a width of 250 mm. It is sufficient for the cutting devices to provide a hole 5 to 10 cm wide which, either by itself or by blowing, is expanded to the width of the fibrous web.

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The resolving means may also be any soft body that contacts the surface of the fibrous web. The surface of the body must be such that it does not damage the tissue. One alternative to the cutting means may be a rubber paw 15 which contacts the surface of the fibrous web. The solution means can be operated, for example, by means of a lever mechanism, which in turn is actuated by a separate actuator. Thus, the cutting means can also be made to follow the web or to rotate another surface against the web.

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The resolution means may be one or more throughout the width of the fibrous web. For example, a ten meter wide fiber web may have one cutting means at a distance of five meters from the edge of the fiber web. Preferably, the cutting means is provided at about 25 m intervals, whereby the fibrous web is divided into a plurality of cutting parts in the transverse direction of the fibrous web machine. Alternatively, o

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, if two cutting tools are used, their position may be cvj "5" at 3.3 m and 6.6 m from the edge of the fiber web. The cutting means ^ are preferably disposed so that they are uniformly distributed over x 30 of the fibrous web,

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cd For more efficient cutting of the fibrous web as an adjunct to cutting tools

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The prior art blowing tubes may be used, which may be applied shortly before or simultaneously with the contact of the cutting means 35 with the fiber web. Blows may be on a fiber web machine in the direction of fiber web 9 travel below, and the blowing need not be synchronized with the cutting means. Alternatively, the arrangement may include, in connection with the cut-off means, the blowing means 23 shown in Figures 2a to 4b. The blowing means 23 may include, for example, blowing lines attached to the cutting means 5 or the like to provide a point air flow to the device. In Figures 3b and 4b, blows of blowing means are designated by reference numeral 23 'and these sharp blows rupture the web at the edges and downwardly against the direction of the ascending web. In this way, the mass of the breakable web also contributes, in addition to blowing, to the rapid cutting of the web.

The arrangement, apparatus and method according to the invention can be used in any application where the fibrous web is supported on its way through the drying section. One advantageous location for cutting tools is the bottom of the drying roller scraper bar, where the cutting tools are easy to maintain. It is also advantageous to place the cutting device close to the group gap, for example on the first vac roll of the drying group on the rising portion of the web 20. Preferably, a bombarded cutting roll is used as the cutting means. For example, a broken camera can be used to control the use of the resolution means. When the break camera detects a break in the fibrous web, automatic control is provided to the cutting means to cut the fibrous web at the selected position.

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The arrangement and device according to the invention are very advantageous, implemented, used and maintained. The solution can already be installed on existing fiber web machines or delivered on new fiber web machines. The solution works without disturbing the thread, x £ 30 since the cutting device is generally detached from the fibrous web.

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Claims (11)

An arrangement in the drying portion of a fiber web machine for cutting the fiber web, according to which the arrangement (10) of the movable fiber web (12) created by the fiber web machine (100) is supported continuously with rollers or weaves (14) in the drying portion (102) of the fiber web machine (100). and which arrangement (10) comprises cutting means (16) for controlled cutting of the supported fiber web (12) at the selected cutting site (18), characterized in that said cutting devices (16) are arranged to at least part of the fiber web (12). ) provide at least a temporary frictional braking contact with the fiber web (12) for cutting the fiber web (12). 2. Arrangement according to claim 1, characterized in that the cutting means (16) comprise an elastic surface for effecting friction sufficient to cut the fiber web (12). Arrangement according to claim 1 or 2, characterized in that said cutting devices (16) comprise one or more cutting rollers (20) which are arranged to be pressed against the fiber web (12) to cut the fiber web (12). 4. Arrangement according to claim 3, characterized in that said cutting roller (20) is freely rotating. co δ c \ j 5. Arrangement according to claim 3 or 4, characterized in that said cutting roller (20) comprises a brake for controlling ° of the rotational resistance of the cutting roller (20). £ 30 Arrangement according to any of claims 1-5, cd c characterized in that said cutting devices (16) are arranged δ to cut the fiber web (12) against said web (14). C \ J Arrangement according to any of claims 1-6, characterized in that the arrangement comprises blowing devices (23) in connection with the cutting devices (16). Apparatus for cutting the fibrous web into a drying portion of a fibrous web machine, wherein the movable fibrous web (12) created by the fibrous web machine (100) is continuously supported by weaves or rollers (14) contained in the drying portion (102) of the fibrous web machine (100), and the device comprising cutting devices (16) for controlled cutting of the supported fiber web (12) at selected cutting site 10 (18), characterized in that said cutting devices (16) are arranged to provide at least a portion of the fiber web (12) at least temporarily by means of friction braking contact with the fiber web (12) for cutting the fiber web (12). Device according to claim 8, characterized in that the cutting devices (16) comprise a freely rotating cutting roller (20) and a brake for controlling the rotation resistance of the cutting roller (20). A method of cutting the fibrous web into the drying portion of a fibrous web machine 20, wherein the movable fibrous web (12) created by the fibrous web machine (100) is continuously supported by weaves or rollers (14) in the dryer portion (102) of the fiber web machine (100), and according to which method the supported fiber web (12) controlled cut at the selected cutting site (18) by external force, characterized in that, according to the method, at least one part of the fiber web (12) is provided at least temporarily with the aid of C a braking contact which slows down the movement V of the fibrous web (12) for cutting the fibrous web (12) and said fibrous web (12) ° is cut against said web (14). I 30 o'clock Method according to claim 10, characterized in that the CO cd contact pays for 0.3 - 3.0 seconds, presumably 0.5 - 1.0 o second. CM