Seal between two pressure zones at a moving surface has a seal holder which applies a clamping force on the seal which is relaxed when the seal is pressed against the surface for effective sealing with low wear

摘要

The seal at the side of at least one moving surface (1) between adjacent overpressure and underpressure zones (2,3), in a papermaking machine, has at least one moving seal (6) within the holding zone (4) of a holder (5), to bear against the moving surface (1) through a press unit (7). The seal holding zone (4) is a clamp holder, and the seal (6) is held in a clamped fit by clamping surfaces (8). The press unit (7), at the same time, applies a force which at least partially relaxes the clamping effect. The press unit (7) applies the full pressure and clamping relief only when the seal (6) is against the moving surface (1). The seal holder zone (4) forms an open channel towards the moving surface (1), preferably with a free quadratic or rectangular free inner cross section surface. Its side walls (9,10) form the clamping surfaces (8). At least one side wall (9) with a clamping surface (8) is elastic or has a sliding or swing movement, and can be moved away against its clamping force line. The clamping force is applied by at least one spring (11) acting on the moving side wall (9). The press unit (7) is at least one pressure hose, especially between the seal (6) and the surface of the holding zone (4) away from the moving surface (1). The moving surface is the inner or outer surface of a suction or blower roller, or a moving belt, with adjacent pressure zones (2,3). Or the seal is between a suction or blower box and the rotating mantle of a suction or blower roller or a belt. The seal (6) is preferably a sealing bar at least generally over the whole length of the roller.