METHOD AND APPARATUS FOR THE CONTACTLESS DETERMINATION OF THE THICKNESS OF A WEB OF MATERIAL, INCLUDING CORRECTION OF THE ALIGNMENT ERROR

摘要

A method for the contactless determination of the thickness of a web of material, for example a web of fibrous material using a sensor array including at least two optical measurement units between which the web can be guided. Each of the optical measurement units includes a measurement plate on the side facing the web. The optical measurement units, which are arranged on opposite sides of the web, are used to measure the distance of the measurement units from the web, and an evaluation unit is used to determine the thickness of the web from the determined distances between the optical measurement units and the web and the distance between the optical measurement units arranged on opposite sides of the web. Multiple optical sensors which are disposed at a distance from each other are associated with the optical measurement units arranged on opposite sides of the web and the evaluation unit is used to determine the angle of inclination of the measurement plates relative to the web and/or an offset between the optical measurement units arranged on opposite sides of the web or between the measurement plates of said units on the basis of the measured values obtained from the optical sensors.