Roller press dewatering fibrous web in paper or card manufacture

摘要

The pressing surface of the roller (14) is supplied with cleaning fluid inside the channel. Preferred features: The washing unit (28) is inside the channel (26). The pressure roller (14) surface is drilled with blind holes and/or includes grooves; or is smooth. The pressure roller has an internal pressure saddle (2) and its pressing surface (12) is flexible. Where subjected to impact of cleaning fluid on the outside, it has an internal strip support under e.g. pneumatic pressure. The support employs a piston-in-cylinder principle. The internally-contacting section of the support, has a smaller radius of curvature than the roller, e.g. it is less than one half-, a quarter- or best of all, one sixth of the roller internal radius. The support lies transverse to the run of the web (L). The cleaning fluid is water, air or steam and/or at least one chemical or mixture. The cleaning unit has one or more of: an oscillating spray tube, an electromechanical, pneumatic or hydraulic oscillatory device, a stationary spray pipe, a fan spray nozzle, a needle jet nozzle, single and/or multiple nozzle head and associated traversing equipment. The channel includes a suction extraction unit (32). A water squeegee also (34) operates inside it.