Web tension measurements in the paper mill

Web tension measuring methods and corresponding instruments have been evaluated at the Graphic Arts Laboratory of the VTT. Together with Valmet Paper Machinery, cross-web tension profiles have been studied in different paper machines and they have been compared to other profiles measured by the process control system in the paper machine. The role of the paper machine tension profile in winding and in paper customer rolls is outlined.The measuring techniques developed seemed to be practical and are from now on available to analyze the paper machine performance. The realized field measurements have shown quite even profiles in basis weight, dry weight and moisture, which are normally measured at the dry end of the paper machine. Web tension can show drastic variation across the web and especially web edges used to be problematic