Fibrous material web producing machine headbox, has lower orifice whose orifice flow length is selected to be less than/equal to orifice flow length of upper orifice so that lower orifice forms lower lip according to width of die gap

摘要

The headbox (1) has an upper orifice (8) positionably arranged in a headbox nozzle (3) on an outlet side of an upper nozzle wall (4). A lower orifice (9) is positionably arranged in the headbox nozzle on an outlet side of a lower nozzle wall (5). An orifice flow length (SL.9) of an orifice flow surface of the lower orifice is selected to be less than or equal to an orifice flow length (SL.8) of an orifice flow surface of the upper orifice in such a way that the lower orifice forms a lower lip (10), with a lower lip projection (L.10), according to width of a die gap.