WO2002068923A1 - Method and device in connection with web tension measurement - Google Patents

Method and device in connection with web tension measurement Download PDF

Info

Publication number
WO2002068923A1
WO2002068923A1 PCT/FI2002/000140 FI0200140W WO02068923A1 WO 2002068923 A1 WO2002068923 A1 WO 2002068923A1 FI 0200140 W FI0200140 W FI 0200140W WO 02068923 A1 WO02068923 A1 WO 02068923A1
Authority
WO
WIPO (PCT)
Prior art keywords
web
measurement
measurement bar
tension
connection
Prior art date
Application number
PCT/FI2002/000140
Other languages
French (fr)
Other versions
WO2002068923A8 (en
Inventor
Kalevi Karhu
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 WO2002068923A1 publication Critical patent/WO2002068923A1/en
Publication of WO2002068923A8 publication Critical patent/WO2002068923A8/en

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes
    • G01L5/04—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring tension in flexible members, e.g. ropes, cables, wires, threads, belts or bands
    • G01L5/045—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring tension in flexible members, e.g. ropes, cables, wires, threads, belts or bands for measuring the tension across the width of a band-shaped flexible member
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
    • B65H23/00—Registering, tensioning, smoothing or guiding webs
    • B65H23/04—Registering, tensioning, smoothing or guiding webs longitudinally
    • B65H23/044—Sensing web tension
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F7/00—Other details of machines for making continuous webs of paper
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21G—CALENDERS; ACCESSORIES FOR PAPER-MAKING MACHINES
    • D21G9/00—Other accessories for paper-making machines
    • D21G9/0009—Paper-making control systems
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes
    • G01L5/04—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring tension in flexible members, e.g. ropes, cables, wires, threads, belts or bands
    • G01L5/08—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring tension in flexible members, e.g. ropes, cables, wires, threads, belts or bands using fluid means

Definitions

  • the invention relates to a method according to the preamble of claim 1.
  • the invention also relates to a device according to the preamble of claim 5.
  • EP application publication 0 367 901 discloses a method and a device for measurement of web tension.
  • the tension of a moving web is measured by placing close to the web a measurement bar having its outer surface curved in the running direction of the web.
  • the measurement bar is provided with holes in which pressure measurement sensors are placed.
  • An air cushion is formed between the moving web and the curved surface, the pressure in the air cushion being proportional to the tension of the web.
  • the tension of the web is measured indirectly by measuring the pressure ofthe air cushion.
  • the device suitable for use in the method comprises means for producing a reference pressure and the pressure measurement device is used for measuring the pressure difference between the reference pressure and the pressure ofthe air cushion.
  • An object of the invention is to create further applications for use in connection with said tension measurement bar.
  • the method according to the invention is mainly characterized by the disclosure in the characterizing part of claim 1.
  • the device according to the invention is in turn mainly characterized by the disclosure in the characterizing part of claim 5.
  • additional functions are arranged in connection with the measurement bar, by which functions it is possible to replace other means and/or devices in connection with the manufacture of a web, in particular a paper or board web and other web-like products.
  • other functions are combined with the measurement bar, so that, in addition to tension measurement and the control associated therewith, said device provides further functions.
  • a dryer By disposing a dryer between measurement bars, or as integrated with a measurement bar or, for example, as a counter surface for the radiation of an infrared dryer, a drying effect is produced in addition to turning the direction of the web.
  • an ultraviolet, microwave, radiation heating or induction heating dryer is used in this connection.
  • the invention provides savings in both investment and operation costs and, in addition, runnability and paper quality are improved.
  • the equipment takes little space and is inexpensive in particular in machine rebuilds.
  • a turning function is provided and a web drying device is disposed in connection with the measurement bar.
  • the curved measurement surface of the measurement bar is formed so as to be at a desired turning angle, for example, 4-35°, preferably 10- 30°, in the running direction of the web.
  • the air pumped by the web i.e. an air cushion, between the shaped measurement surface of the measurement bar and the web keeps the web apart from the device.
  • a profiling dryer is arranged in connection with the measurement bar, whereby it is possible to adjust the tension profile.
  • an infrared dryer is connected to the measurement bar, by means of which it is possible to carry out, for example, the drying profiling of coating, which, when necessary, makes it possible to prevent the spreading need of the web and eliminate problems associated with web wrinkles in situations in which the "living" ofthe web is not even in the cross direction.
  • the moisture profile can also be affected by means ofthe invention.
  • the moisture profile is affected such that after coating more water penetrates into the base paper at wet locations with the result that the web becomes slack at these locations. In that connection, more drying energy can be applied to these areas.
  • the web is dried in the area where water has been bound into the fibres, i.e. at a solids content of over 60 %, the fibres contract in the cross direction (in the machine, the fibres are normally in the longitudinal direction) and tension increases when drying energy is increased.
  • drying capacity is adjusted based on tension measurement in the cross direction such that higher drying capacity is directed at the areas of lower tension.
  • tension measurement is carried out by means of the measurement bar and the moisture profile is corrected by means of drying.
  • This embodiment of the invention is suitable for use, for example, in a press section and at the end ofthe machine.
  • the measurement bar is used as a turning device in addition to tension measurement, and a drying effect, or a spreading effect or other suitable devices are combined therewith in an appropriate manner.
  • a web W is conducted from an unwind station 31 past a measurement station 33 to a coating station.
  • An arrangement in accordance with the invention is placed before and after the coating station 30 of the web W, which arrangement comprises a tension measurement bar 20 with a dryer 22 arranged in connection therewith, the dryer 22 being followed by dryers 23, 24 whose counter radiators 25, 26, 27 are located on the opposite side ofthe web, and after a guide roll 35 there is a winding device 40 for the web.
  • the measurement bar 20 turns the running direction ofthe web W in a contactless manner by means of an air cushion formed between a curved measurement surface and the web W.
  • the dryers 22, 23, 24 are, for example, infrared, ultraviolet, microwave, radiation heating and/or induction heating dryers. Counter radiators 25, 26, 27 are used, when needed. On the opposite side there may also be another radiator or an air dryer. When desired, the dryers may be profiling dryers.
  • the tension profile of the web can also be affected by the arrangement in accordance with the invention, when placed before a coating station.

Abstract

The invention relates to a method and a device in connection withweb tension measurement. In the method, the tension of a web (W) is measured by a measurement bar (20) placed in the vicinity of the web, the measurement bar having an outer surface (21) which is curved in the running direction (S) of the web (W), and in which an air cushion is formed between the moving web(W) and the curved surface (21). In the method, the web (W) is dried by a web drying device (22,23,24;25,26,27) provided in the immediate vicinityof the measurement bar (20).

Description

Method and device in connection with web tension measurement
The invention relates to a method according to the preamble of claim 1.
The invention also relates to a device according to the preamble of claim 5.
EP application publication 0 367 901 discloses a method and a device for measurement of web tension. The tension of a moving web is measured by placing close to the web a measurement bar having its outer surface curved in the running direction of the web. The measurement bar is provided with holes in which pressure measurement sensors are placed. An air cushion is formed between the moving web and the curved surface, the pressure in the air cushion being proportional to the tension of the web. The tension of the web is measured indirectly by measuring the pressure ofthe air cushion. The device suitable for use in the method comprises means for producing a reference pressure and the pressure measurement device is used for measuring the pressure difference between the reference pressure and the pressure ofthe air cushion.
One example of this type of prior art device is the measurement bar which is marketed by the applicant under the trademark IQ Tension and which is used, for example, in connection with the manufacture of a paper web for measuring the tension of the web, for example, placed in connection with winding after a spreader roll, and which is described, for example, in the magazine article Pekka Rinne: "Tension profile is inherited", Paper News, vol. 14, no. 3, pp. 46-49.
An object of the invention is to create further applications for use in connection with said tension measurement bar. With a view to achieving the above-noted objects as well as the ones which will come out later, the method according to the invention is mainly characterized by the disclosure in the characterizing part of claim 1.
The device according to the invention is in turn mainly characterized by the disclosure in the characterizing part of claim 5.
In accordance with the invention, additional functions are arranged in connection with the measurement bar, by which functions it is possible to replace other means and/or devices in connection with the manufacture of a web, in particular a paper or board web and other web-like products. Thus, other functions are combined with the measurement bar, so that, in addition to tension measurement and the control associated therewith, said device provides further functions. By disposing a dryer between measurement bars, or as integrated with a measurement bar or, for example, as a counter surface for the radiation of an infrared dryer, a drying effect is produced in addition to turning the direction of the web. In accordance with additional features ofthe invention, instead of infrared drying, an ultraviolet, microwave, radiation heating or induction heating dryer is used in this connection.
The invention provides savings in both investment and operation costs and, in addition, runnability and paper quality are improved. The equipment takes little space and is inexpensive in particular in machine rebuilds.
In accordance with one advantageous embodiment of the invention, a turning function is provided and a web drying device is disposed in connection with the measurement bar. The curved measurement surface of the measurement bar is formed so as to be at a desired turning angle, for example, 4-35°, preferably 10- 30°, in the running direction of the web. In this embodiment, the air pumped by the web, i.e. an air cushion, between the shaped measurement surface of the measurement bar and the web keeps the web apart from the device. Thus, by alternating a tension measurement bar having a desired curvature (all the units are not necessarily coupled to tension measurement) with a dryer in the running direction ofthe web, the web can be turned and dried without a traditional turning device.
In accordance with one advantageous additional feature, for example, a profiling dryer is arranged in connection with the measurement bar, whereby it is possible to adjust the tension profile.
In the embodiment in accordance with one advantageous additional feature, an infrared dryer is connected to the measurement bar, by means of which it is possible to carry out, for example, the drying profiling of coating, which, when necessary, makes it possible to prevent the spreading need of the web and eliminate problems associated with web wrinkles in situations in which the "living" ofthe web is not even in the cross direction. The moisture profile can also be affected by means ofthe invention.
The moisture profile is affected such that after coating more water penetrates into the base paper at wet locations with the result that the web becomes slack at these locations. In that connection, more drying energy can be applied to these areas. When the web is dried in the area where water has been bound into the fibres, i.e. at a solids content of over 60 %, the fibres contract in the cross direction (in the machine, the fibres are normally in the longitudinal direction) and tension increases when drying energy is increased.
In accordance with one advantageous feature of the invention, drying capacity is adjusted based on tension measurement in the cross direction such that higher drying capacity is directed at the areas of lower tension.
In the invention, in accordance with an advantageous embodiment, tension measurement is carried out by means of the measurement bar and the moisture profile is corrected by means of drying. This embodiment of the invention is suitable for use, for example, in a press section and at the end ofthe machine.
In accordance with some advantageous embodiments of the invention, the measurement bar is used as a turning device in addition to tension measurement, and a drying effect, or a spreading effect or other suitable devices are combined therewith in an appropriate manner.
In the following, the invention will be described in greater detail with reference to the figure in the accompanying drawing, to the details of which the invention is, however, not by any means meant to be strictly confined.
In the embodiment ofthe invention illustrated in the figure, a web W is conducted from an unwind station 31 past a measurement station 33 to a coating station. An arrangement in accordance with the invention is placed before and after the coating station 30 of the web W, which arrangement comprises a tension measurement bar 20 with a dryer 22 arranged in connection therewith, the dryer 22 being followed by dryers 23, 24 whose counter radiators 25, 26, 27 are located on the opposite side ofthe web, and after a guide roll 35 there is a winding device 40 for the web. The measurement bar 20 turns the running direction ofthe web W in a contactless manner by means of an air cushion formed between a curved measurement surface and the web W. The dryers 22, 23, 24 are, for example, infrared, ultraviolet, microwave, radiation heating and/or induction heating dryers. Counter radiators 25, 26, 27 are used, when needed. On the opposite side there may also be another radiator or an air dryer. When desired, the dryers may be profiling dryers. The tension profile of the web can also be affected by the arrangement in accordance with the invention, when placed before a coating station.

Claims

Claims
1. A method in connection with web tension measurement, in which method the tension of a web (W) is measured by a measurement bar (20) placed in the vicinity ofthe web, the measurement bar having an outer surface (21) which is curved in the running direction (S) of the web (W), and in which an air cushion is formed between the moving web (W) and the curved surface (21), characterized in that, in the method, the web (W) is dried by a web' drying device (22, 23, 24; 25, 26, 27) provided in the immediate vicinity of the measurement bar (20).
2. A method according to claim 1, characterized in that, in the method, the measurement bar (20) is used for turning the running direction of the moving web (W).
3. A method according to claim 1, characterized in that, in the method, the web (W) is dried by a profiling dryer (22, 23, 24).
4. A method according to claim 3, characterized in that, in the method, drying capacity is adjusted based on tension measurement in the cross direction such that higher drying capacity is directed at areas of lower tension.
5. A method according to claim 2, characterized in that, in the method, the running direction ofthe web is turned in a contactless manner by means of an air cushion formed between the measurement surface (21) ofthe measurement bar (20) and the web (W).
6. A device in connection with web tension measurement, which device comprises a measurement bar (20) having an outer surface (21) which is curved in the running direction (S) of a web (W), characterized in that a dryer (22, 23, 24; 25, 26, 27) has been arranged in connection with the measurement bar (20).
A device according to claim 6, characterized in that the outer surface of the measurement bar (20) is curved in the running direction (S) ofthe web (W) to the extent of a desired turning angle (α).
A device according to claim 6 or 7, characterized in that a profiling dryer has been arranged in connection with the measurement bar (20).
A device according to any one of claims 6 to 8, characterized in that the device is used in the manufacture of a paper or board web.
A device according to claim 9, characterized in that the device is placed in connection with a coating station (30).
PCT/FI2002/000140 2001-02-27 2002-02-21 Method and device in connection with web tension measurement WO2002068923A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FI20010390 2001-02-27
FI20010390A FI110212B (en) 2001-02-27 2001-02-27 Method and apparatus for measuring web tension

Publications (2)

Publication Number Publication Date
WO2002068923A1 true WO2002068923A1 (en) 2002-09-06
WO2002068923A8 WO2002068923A8 (en) 2003-12-04

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Application Number Title Priority Date Filing Date
PCT/FI2002/000140 WO2002068923A1 (en) 2001-02-27 2002-02-21 Method and device in connection with web tension measurement

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WO (1) WO2002068923A1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1413672A1 (en) * 2002-10-23 2004-04-28 Voith Paper Patent GmbH Device for indirect or direct registration of a local web tension of a running material in web form at at least one crossdirectional position
WO2011134487A1 (en) * 2010-04-26 2011-11-03 Metso Paper, Inc. Method for controlling a tension profile of a web and web tension profile control apparatus

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0367901A2 (en) * 1988-09-14 1990-05-16 Valmet Paper Machinery Inc. Method and apparatus for measurement of web tension
WO1991003600A1 (en) * 1989-09-04 1991-03-21 Davy Mckee (Poole) Limited Improvements in the manufacture of web materials
US5649448A (en) * 1994-05-16 1997-07-22 Valmet Corporation System for overall control of different transverse profiles in a paper web manufactured in a board of paper machine and/or treated in a finishing machine
WO2001000924A1 (en) * 1999-06-24 2001-01-04 Metso Paper Automation Oy Method and apparatus for controlling a moving paper web

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0367901A2 (en) * 1988-09-14 1990-05-16 Valmet Paper Machinery Inc. Method and apparatus for measurement of web tension
WO1991003600A1 (en) * 1989-09-04 1991-03-21 Davy Mckee (Poole) Limited Improvements in the manufacture of web materials
US5649448A (en) * 1994-05-16 1997-07-22 Valmet Corporation System for overall control of different transverse profiles in a paper web manufactured in a board of paper machine and/or treated in a finishing machine
WO2001000924A1 (en) * 1999-06-24 2001-01-04 Metso Paper Automation Oy Method and apparatus for controlling a moving paper web

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1413672A1 (en) * 2002-10-23 2004-04-28 Voith Paper Patent GmbH Device for indirect or direct registration of a local web tension of a running material in web form at at least one crossdirectional position
WO2011134487A1 (en) * 2010-04-26 2011-11-03 Metso Paper, Inc. Method for controlling a tension profile of a web and web tension profile control apparatus

Also Published As

Publication number Publication date
FI20010390A (en) 2002-08-28
FI20010390A0 (en) 2001-02-27
FI110212B (en) 2002-12-13
WO2002068923A8 (en) 2003-12-04

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