METHOD OF TREATING A FIBER WEB AND A TREATMENT SYSTEM FOR TREATMENT OF A FIBER WEB

The invention relates to a method of treating a fiber web, in which method the fiber web (W) is treated in a treatment system (10), in particular coated by curtain coating or sized by curtain sizing, which treatment system (10) comprises at least one curtain application device (20) and two treatment rolls (30) between of which treatment rolls (30) a treatment nip (N) is formed, in which method at least one curtain (C) of a treatment substance is provided by the application device (20). In the method an application device (20), which comprises a distribution chamber (21), at least one feed opening (20F), at least one flow-through (20FT) and a lip opening (24), is used to provide the curtain (C) of the treatment substance and in the method profile of the applied treatment substance in cross direction of the fiber web (W) i.e. in longitudinal direction of the application device (20) is controlled by at least one means configured to adjust flow of the treatment substance in the distribution chamber (21). The invention also relates to a treatment system for treatment of a fiber web (W), in particular a coating system for curtain coating or a sizing system for curtain sizing, which treatment system (10) comprises at least one curtain application device (20) and two treatment rolls (30) between of which treatment rolls (30) a treatment nip (N) is formed. The application device (20) comprises a distribution chamber (21), at least one feed opening (20F), at least one flow-through (20FT) and a lip opening (24) and the treatment system (10) further comprises at least one means configured to adjust flow of the treatment substance in the distribution chamber (21) to control the profile of the treatment substance applied in cross direction of the fiber web (W) i.e. in longitudinal direction of the application device (20).