Method and device for tracking the edge of a web
AssigneeMetso Paper, Inc.
InventorsJyrki Saloniemi, Samppa J. Salminen, Reijo Huuskonen
Life of this patent
Estimating the term…
Abstract
A method and a device for tracking the position of the edge of a moving web (12), such as a fabric or a web of a paper machine, in which method a pressure-sensitive sensor element (14) is disposed in/onto the surface of the roll (10) guiding the web (12), which sensor element reacts to the pressure applied to it by the moving web (12) by producing an electric signal, on the basis of which it is possible to determine the exact position of the edge of the web (12) on the roll (10). The band-like sensor element (14) comprises one single sensor strip or several sensor strips (141 . . . 14n) disposed successively in the band.
Claims20
A method for tracking position of an edge of a moving web in a paper or board making machine comprising the steps of:
- detecting an electronic signal received from a pressure-sensitive sensor element positioned on an element having a surface over which the moving web travels, the electrical signal being produced by reaction of the pressure-sensitive sensor element to pressure applied to the pressure-sensitive sensor by the moving web;
- and
- determining the exact position of the edge of the moving web based on the electronic signal produced by the pressure-sensitive sensor element.
An apparatus for tracking position of an edge of a moving web in a paper or board making machine, the apparatus comprising:
- a web mounted for motion in the paper or board making machine;
- an element having a surface positioned with respect to the web so that motion of the web is over the element;
- and
- a band-like electrical pressure-sensing sensor element positioned on the element, and responsive, by the production of an electrical signal, to pressure produced by the web when it is moved over at least a portion of the pressure-sensing sensor element on the element, the electrical signal magnitude corresponding to the pressure applied.
The apparatus of claim 111 wherein the band-like sensor element comprises two or more sensor strips spaced at a small distance from one another, each sensor strip separately responsive, by the production of an electrical signal, to pressure produced by the web when it is moved over at least a portion of each sensor strip, and further comprising means for determining the position of the edge of the web by comparing the signals produced by the sensor strips with one another.
The apparatus of claim the 11 wherein the element having the surface positioned with respect to the web so that motion of the web is over the element, is a roll having a surface, and the surface positioned with respect to the web is the surface of the roll.
The apparatus of claim the 16 wherein the band-like electrical pressure-sensing sensor comprises a single sensor strip disposed axially on the surface of the roll, and further comprises means for determining the position of the edge of the web based on the signal produced by the sensor element.
The apparatus of claim the 16 wherein the band-like electrical pressure-sensing sensor is disposed spirally on the roll at a helix angle, and further comprising means for measuring the rotation speed of the roll and means for determining the position of the edge of the web based on a signal produced by the band-like electrical pressure-sensing sensor, and on the helix angle of the spiral and on the measured rotation speed.
A method for tracking position of an edge of a moving web in a paper or board making machine comprising the steps of:
- detecting an electronic signal received from a pressure-sensitive sensor element positioned on a roll, the roll having a surface, wherein at each instant in time as the roll rotates with the moving web, a first portion of the roll surface engages the moving web, and a second portion moves out of engagement with the moving web, the electrical signal being produced by reaction of the pressure-sensitive sensor element to pressure applied to the pressure-sensitive sensor by the moving web when the pressure-sensitive sensor element is on the first portion of the roll surface engaging the moving web;
- comparing the electrical signal received from the pressure-sensitive sensor when the pressure-sensitive sensor is on the portion of the roll surface engaging the moving web and so subjected to pressure, with the electrical signal received from the pressure-sensitive sensor when the pressure sensor is on the portion of the roll surface not engaging the roll and so not subjected to pressure;
- determining the position of the edge of the moving web based on the electronic signal produced by the pressure-sensitive sensor element when subjected to pressure as compared with the electrical signal received from the pressure-sensitive sensor when the pressure sensor is on the portion of the roll surface not engaging the roll and so not subjected to pressure;
- and
- transmitting the signals produced by the sensor element wirelessly from a transmitter at an end of the roll to a receiver situated outside the roll.
Dependencies are inferred from the claim text.