Web e.g. paper web, moisture profile determining method for preventing flatness deviation in dryer section of fibrous material web machine, involves controlling drying of web based on measured moisture of web

摘要

The method involves directly measuring moisture of a web (28) e.g. paper web and cardboard web, in z-direction using a drying filter (26) of a dryer section (14), where moisture of the web is measured for different web thicknesses. The web is supported at a side in a machine direction (MD) measuring position (30) in a transverse direction. The drying of the web is controlled based on measured moisture by controlling drying parameters of a fibrous material web machine. Flatness deviation is calculated based on the measured moisture. An independent claim is also included for an arrangement for determining moisture profile of a web in a longitudinal direction and for preventing flatness deviation in a dryer section of a fibrous material web machine.