WO2004092480A1 - A method and an apparatus for cutting a material web - Google Patents

A method and an apparatus for cutting a material web Download PDF

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Publication number
WO2004092480A1
WO2004092480A1 PCT/FI2004/050039 FI2004050039W WO2004092480A1 WO 2004092480 A1 WO2004092480 A1 WO 2004092480A1 FI 2004050039 W FI2004050039 W FI 2004050039W WO 2004092480 A1 WO2004092480 A1 WO 2004092480A1
Authority
WO
WIPO (PCT)
Prior art keywords
web
weakened
material web
cutting
paper machine
Prior art date
Application number
PCT/FI2004/050039
Other languages
French (fr)
Inventor
Petri Enwald
Petteri Lannes
Teppo Kojo
Original Assignee
Metso Paper, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Metso Paper, Inc. filed Critical Metso Paper, Inc.
Publication of WO2004092480A1 publication Critical patent/WO2004092480A1/en

Links

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B65CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65HHANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
    • B65H19/00Changing the web roll
    • B65H19/22Changing the web roll in winding mechanisms or in connection with winding operations
    • B65H19/26Cutting-off the web running to the wound web roll
    • B65H19/267Cutting-off the web running to the wound web roll by tearing or bursting
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B26HAND CUTTING TOOLS; CUTTING; SEVERING
    • B26FPERFORATING; PUNCHING; CUTTING-OUT; STAMPING-OUT; SEVERING BY MEANS OTHER THAN CUTTING
    • B26F3/00Severing by means other than cutting; Apparatus therefor
    • B26F3/002Precutting and tensioning or breaking
    • DTEXTILES; PAPER
    • D21PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21FPAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F7/00Other details of machines for making continuous webs of paper
    • D21F7/04Paper-break control devices
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B65CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65HHANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
    • B65H2301/00Handling processes for sheets or webs
    • B65H2301/50Auxiliary process performed during handling process
    • B65H2301/51Modifying a characteristic of handled material
    • B65H2301/512Changing form of handled material
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B65CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65HHANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
    • B65H2301/00Handling processes for sheets or webs
    • B65H2301/50Auxiliary process performed during handling process
    • B65H2301/51Modifying a characteristic of handled material
    • B65H2301/514Modifying physical properties
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B65CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65HHANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
    • B65H2301/00Handling processes for sheets or webs
    • B65H2301/50Auxiliary process performed during handling process
    • B65H2301/51Modifying a characteristic of handled material
    • B65H2301/515Cutting handled material
    • B65H2301/5151Cutting handled material transversally to feeding direction
    • B65H2301/51514Breaking; Bursting; Tearing, i.e. cutting without cutting member
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B65CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65HHANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
    • B65H2301/00Handling processes for sheets or webs
    • B65H2301/50Auxiliary process performed during handling process
    • B65H2301/51Modifying a characteristic of handled material
    • B65H2301/515Cutting handled material
    • B65H2301/5153Details of cutting means
    • B65H2301/51534Water jet
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B65CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65HHANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
    • B65H2701/00Handled material; Storage means
    • B65H2701/10Handled articles or webs
    • B65H2701/12Surface aspects

Definitions

  • This invention relates to a method and an apparatus for cutting a material web in a paper machine or the like.
  • the material web is weakened locally and after that cut at the weakened location.
  • Reel change can be performed, for example, in such a manner that when the full paper reel, the so-called machine reel, is separated from the reeling cylinder, its speed decreases and a bag begins to form in the material web between the reeling cylinder and the full reel, which bag is blown around an empty reel spool, in which case the web at the same time tears.
  • Web cutting with a full width percussive blade cutting device is also often used so that as small amount as possible of the material web is wasted and that the changing event would be neat without any loose material resulting from the tearing. After cutting, the material web is directed around the new reel spool.
  • the method according to the invention is characterized in that the web is weakened at the latest when the dry matter content of the web is at least 8 % lower than the web dry matter content for the reel-up.
  • the apparatus according to the invention is characterized in that the apparatus for weakening the material web is placed before the dryer section of the paper machine or the like, or at the latest in the area of the calender section.
  • the material web can be cut in a controlled manner and with a uniform quality.
  • web cutting is performed by means of the method according to the invention, it is possible that the web can be cut in the nip only by means of a stress peak caused in the web in the machine direction by the deformation.
  • a paper machine or the like in this application refers to, in addition to an actual paper machine, also a soft tissue machine and a board machine, and the material web is the product received from these machines.
  • a paper machine comprises, starting from the beginning of paper manufacturing, a headbox, a wire section, a press section, a dryer section, a coating section, a calender section and a reeling section.
  • the fibre suspension from the headbox is arrange to spread on the wire and in the wire section, the paper is formed into a web- like form, and water is removed from it by means of gravity and suction.
  • the press section excess water is further pressed from the web and the fibres are forced into contact with each other.
  • the dryer section after the press section water is removed by evaporation and fibre bondings are formed in contact with hot surfaces.
  • the calender section the paper is calendered, in which case paper becomes thinner, i.e.
  • the finished material web is reeled.
  • the above-described sections are typical sections of a paper machine, and it is possible that there are other sections besides the ones described in a paper machine.
  • the above-mentioned sections may be repeated, e.g. the coating and dryer sections.
  • the fibre orientation of the web has an effect on how easily the web is cut. Especially when using gap formers, the fibres are oriented in such a manner that the tensile strength in the machine direction becomes great. This is, of course, disadvantageous from the point of view of cutting the web, because cutting the web requires more power.
  • the material web is cut in such a manner that the material web is weakened before its dry content matter has risen so high that its strength has reached its substantially normal strength.
  • cutting the web is controlled and of even quality in the cross machine direction.
  • the moisture of a finished paper is below 12 %. Weakening is performed on a very narrow area in the longitudinal direction of the web.
  • the weakening is caused in the pulp forming into a web by affecting the orientation of wood fibres or their amount per unit volume.
  • the weakening can also be performed by temporarily changing the dosage of some additive.
  • This kind of an agent can be, for example, a retention aid.
  • the weakening can be performed over the area of the entire web width or a part of the web width, for example, only on the edges of the web or in the centre of the web. If the weakening is performed for the entire width of the web, conveying the web forward in the paper machine in a supported manner can be necessary.
  • Weakening can be performed by dosing liquid onto the web in a controlled manner, by using gas blowing, by affecting the physical or chemical properties of the fibres or by using a device, which contacts the web mechanically.
  • liquid When liquid is dosed on the web, it is advantageously water, and it can be, for example, sprayed with nozzles onto the forming web.
  • the gas used in gas blowing is advantageously air, and in air blowing, a narrow weakened place is formed on the web.
  • the physical properties, which can be affected are, for example, the strength properties of the fibres or their electric properties.
  • the mechanically contacting device can be, for example, a percussive blade, which causes a local weakening.
  • the web weakening can be arranged in such a manner that in the cross direction of the web, a beam runs over the web close to it, to which beam the means performing the above-mentioned functions are mounted.
  • Liquid or gas nozzles can be mounted on the beams, or electrodes taking part in forming an electric field or devices required for forming a magnetic field.
  • the weakening is, for example, in the shape of an arrowhead. This kind of a shape can be created through the combined effect of the web movement with the nozzles mounted on the beam and moving in the cross direction of the web.
  • Web weakening can also be implemented by dosing agents temporarily weakening the web into the fibre pulp coming from the headbox, by changing the speed difference between the headbox discharge and the receiving wire, or by temporarily weakening the flow of the fibre pulp from the headbox.
  • the agent weakening the web can be dosed among the liquid brought onto the web, or the agent can be brought onto a certain point of the web in a dry form, for example as a powder.
  • the web weakening agent can affect the chemistry between the fibres, for example the ability of the fibre fibrils to form bonds between fibres, or other fibre properties. The formation of bonds between fibres can be affected, for example, by changes in the pH.
  • the weakened web can be cut advantageously in the reeling nip by means of the stress peak caused in the web in the machine direction by the deformation. It is also possible that the cutting takes place only by means of web tension. It is also possible to cause an edge tear in the web in order to start the cutting event. The edge tear is usually made at such point of the process where the web travels unsupported, for example at the reel-up. Most advantageously the invention can be applied in processes where the web transfer is entirely closed before the reel-up, in which case the risk of a break is minimized. Since the weakening is very short-term, it does not disturb the on-line measuring devices.
  • the above description does not restrict the invention, but the invention may vary within the scope of the claims.
  • the controlled weakening according to the invention can be utilized in all other situations where the web is desired to be cut in a controlled manner, such as, for example when running the web to a pulper.
  • the main idea in this invention is that the material web is weakened before the dryer section of a paper machine, or at the latest when the dry matter content of the web is at least 8 % lower than the dry matter content of the web at the reel-up, i.e. before the strength of the material web has risen close to the strength of the material web.

Abstract

The invention relates to a method for cutting a material web in a paper machine or the like. In the method, the material web is weakened locally and after that cut at the weakened location. The web is weakened at the latest when the dry matter content of the web is at least 8% lower than the dry matter content of the web for the reel-up. The invention also relates to an apparatus for weakening the material web for cutting, which is placed before the dryer section of a paper machine or the like.

Description

A method and an apparatus for cutting a material web
This invention relates to a method and an apparatus for cutting a material web in a paper machine or the like. In the method, the material web is weakened locally and after that cut at the weakened location.
Generally, cutting the material web in a paper machine or the like takes place at the reel-up during reel change. At a so-called Pope reel-up or at the so-called second generation reel-ups developed from that, in a continuous reel-up of the material web, a new reel spool is often changed into the place of a full reel in such a manner that it is accelerated substantially into a rotating speed corresponding to the web speed of the web and it is lowered or in some other manner taken into contact with the means forming a reeling supporting surface, such as the reeling cylinder.
Reel change can be performed, for example, in such a manner that when the full paper reel, the so-called machine reel, is separated from the reeling cylinder, its speed decreases and a bag begins to form in the material web between the reeling cylinder and the full reel, which bag is blown around an empty reel spool, in which case the web at the same time tears.
Web cutting with a full width percussive blade cutting device is also often used so that as small amount as possible of the material web is wasted and that the changing event would be neat without any loose material resulting from the tearing. After cutting, the material web is directed around the new reel spool.
When the speeds of the paper machine increase, a fast and controlled cutting of the web is challenging and requires very fast functioning special devices for full width cutting. Web tearing during free draught after an edge tear has been made is uncontrollable. In known cutting methods, the web is forced to always be cut substantially after the reeling nip, either during freed draught or supported onto the surface of the roll. By means of the method according to the invention, it is possible to decrease the above-mentioned problems. The method according to the invention is characterized in that the web is weakened at the latest when the dry matter content of the web is at least 8 % lower than the web dry matter content for the reel-up. The apparatus according to the invention is characterized in that the apparatus for weakening the material web is placed before the dryer section of the paper machine or the like, or at the latest in the area of the calender section.
By means of the method according to the invention, the material web can be cut in a controlled manner and with a uniform quality. When web cutting is performed by means of the method according to the invention, it is possible that the web can be cut in the nip only by means of a stress peak caused in the web in the machine direction by the deformation.
A paper machine or the like in this application refers to, in addition to an actual paper machine, also a soft tissue machine and a board machine, and the material web is the product received from these machines.
The phases of paper manufacturing are described briefly in the following. A paper machine comprises, starting from the beginning of paper manufacturing, a headbox, a wire section, a press section, a dryer section, a coating section, a calender section and a reeling section. The fibre suspension from the headbox is arrange to spread on the wire and in the wire section, the paper is formed into a web- like form, and water is removed from it by means of gravity and suction. In the press section, excess water is further pressed from the web and the fibres are forced into contact with each other. In the dryer section after the press section, water is removed by evaporation and fibre bondings are formed in contact with hot surfaces. In the calender section the paper is calendered, in which case paper becomes thinner, i.e. it is pressed together and it receives a smooth surface. In the reeling section, the finished material web is reeled. The above-described sections are typical sections of a paper machine, and it is possible that there are other sections besides the ones described in a paper machine. In addition, in an on-machine solution the above-mentioned sections may be repeated, e.g. the coating and dryer sections.
The fibre orientation of the web has an effect on how easily the web is cut. Especially when using gap formers, the fibres are oriented in such a manner that the tensile strength in the machine direction becomes great. This is, of course, disadvantageous from the point of view of cutting the web, because cutting the web requires more power.
In the method according to the invention, the material web is cut in such a manner that the material web is weakened before its dry content matter has risen so high that its strength has reached its substantially normal strength. Thus, cutting the web is controlled and of even quality in the cross machine direction. Generally, the moisture of a finished paper is below 12 %. Weakening is performed on a very narrow area in the longitudinal direction of the web.
In the method according to the invention, the weakening is caused in the pulp forming into a web by affecting the orientation of wood fibres or their amount per unit volume. The weakening can also be performed by temporarily changing the dosage of some additive. This kind of an agent can be, for example, a retention aid. The weakening can be performed over the area of the entire web width or a part of the web width, for example, only on the edges of the web or in the centre of the web. If the weakening is performed for the entire width of the web, conveying the web forward in the paper machine in a supported manner can be necessary.
Weakening can be performed by dosing liquid onto the web in a controlled manner, by using gas blowing, by affecting the physical or chemical properties of the fibres or by using a device, which contacts the web mechanically. When liquid is dosed on the web, it is advantageously water, and it can be, for example, sprayed with nozzles onto the forming web. The gas used in gas blowing is advantageously air, and in air blowing, a narrow weakened place is formed on the web. The physical properties, which can be affected are, for example, the strength properties of the fibres or their electric properties. The mechanically contacting device can be, for example, a percussive blade, which causes a local weakening. In practice, the web weakening can be arranged in such a manner that in the cross direction of the web, a beam runs over the web close to it, to which beam the means performing the above-mentioned functions are mounted. Liquid or gas nozzles can be mounted on the beams, or electrodes taking part in forming an electric field or devices required for forming a magnetic field. It is also possible that the weakening is, for example, in the shape of an arrowhead. This kind of a shape can be created through the combined effect of the web movement with the nozzles mounted on the beam and moving in the cross direction of the web. Web weakening can also be implemented by dosing agents temporarily weakening the web into the fibre pulp coming from the headbox, by changing the speed difference between the headbox discharge and the receiving wire, or by temporarily weakening the flow of the fibre pulp from the headbox. Alternatively, the agent weakening the web can be dosed among the liquid brought onto the web, or the agent can be brought onto a certain point of the web in a dry form, for example as a powder. The web weakening agent can affect the chemistry between the fibres, for example the ability of the fibre fibrils to form bonds between fibres, or other fibre properties. The formation of bonds between fibres can be affected, for example, by changes in the pH.
The weakened web can be cut advantageously in the reeling nip by means of the stress peak caused in the web in the machine direction by the deformation. It is also possible that the cutting takes place only by means of web tension. It is also possible to cause an edge tear in the web in order to start the cutting event. The edge tear is usually made at such point of the process where the web travels unsupported, for example at the reel-up. Most advantageously the invention can be applied in processes where the web transfer is entirely closed before the reel-up, in which case the risk of a break is minimized. Since the weakening is very short-term, it does not disturb the on-line measuring devices.
The above description does not restrict the invention, but the invention may vary within the scope of the claims. The controlled weakening according to the invention can be utilized in all other situations where the web is desired to be cut in a controlled manner, such as, for example when running the web to a pulper. The main idea in this invention is that the material web is weakened before the dryer section of a paper machine, or at the latest when the dry matter content of the web is at least 8 % lower than the dry matter content of the web at the reel-up, i.e. before the strength of the material web has risen close to the strength of the material web.

Claims

Claims:
1. A method for cutting a material web in a paper machine or the like, in which method the material web is weakened locally and after that cut at the weakened point, characterized in that the web is weakened at the latest when the dry matter content of the web is at least 8 % lower than the web dry matter content at the reel-up.
2. The method according to claim 1 , characterized in that the web is weakened in the cross direction of the web either partly or entirely.
3. The method according to claim 1 , characterized in that the web is weakened by temporarily changing the dosage of the agent affecting the web forming, such as the retention agent.
4. The method according to claim 1 , characterized in that the web is weakened by affecting the orientation and/or amount of the fibres at a certain cross-directional area of the web.
5. The method according to claim 4, characterized in that the web is weakened by dosing liquid onto the material web.
6. The method according to claim 4, characterized in that the web is weakened by blowing gas onto the material web.
7. The method according to claim 4, characterized in that the web is weakened by affecting the physical properties of the fibres, such as the strength properties or the electrical properties.
8. The method according to claim 4, characterized in that the web is weakened by affecting the chemical properties of the fibres.
9. The method according to claim 1 or 2, characterized in that the web is weakened by affecting the fibre properties in such a manner that fibre binding to each other is prevented or weakened.
10. The method according to claim 4, characterized in that the web is weakened by means of a mechanical device, which is arranged to contact the material web.
11. The method according to any of the preceding claims, characterized in that the web is weakened at the wire section or the press section of the paper machine.
12. An apparatus for weakening a material web for cutting, characterized in that the apparatus for weakening the material web is placed before the dryer section of a paper machine or the like.
13. The apparatus according to claim 12, characterized in that it is placed in the wire section or the press section of a paper machine.
PCT/FI2004/050039 2003-04-17 2004-04-16 A method and an apparatus for cutting a material web WO2004092480A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FI20030585A FI117553B (en) 2003-04-17 2003-04-17 Method and apparatus for cutting material web
FI20030585 2003-04-17

Publications (1)

Publication Number Publication Date
WO2004092480A1 true WO2004092480A1 (en) 2004-10-28

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ID=8565984

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/FI2004/050039 WO2004092480A1 (en) 2003-04-17 2004-04-16 A method and an apparatus for cutting a material web

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FI (1) FI117553B (en)
WO (1) WO2004092480A1 (en)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6073824A (en) * 1999-03-22 2000-06-13 Kimberly-Clark Worldwide, Inc. Apparatus and method for cleanly breaking a continuously advancing cellulose web
US6328248B1 (en) * 1998-10-22 2001-12-11 Voith Sulzer Papiertechnik Patent Gmbh Winding machine and winding method

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6328248B1 (en) * 1998-10-22 2001-12-11 Voith Sulzer Papiertechnik Patent Gmbh Winding machine and winding method
US6073824A (en) * 1999-03-22 2000-06-13 Kimberly-Clark Worldwide, Inc. Apparatus and method for cleanly breaking a continuously advancing cellulose web

Also Published As

Publication number Publication date
FI20030585A (en) 2004-10-18
FI20030585A0 (en) 2003-04-17
FI117553B (en) 2006-11-30

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