Papermaking roller with flexible casing passing over shoe exerting mechanical pressure, includes casing guidance-, bearing-, lubrication- and anti-leakage provisions

摘要

The flexible roller casing (14) is guided over the pressure shoe (12). This arrangement forms a nip (16) against the opposed support, which is prolonged along the web travel. Edges (18) of the driven casing (14) slide against and are carried in, fixed side supports (20) which act as bearings. Between the pressure shoe and the casing, there is lubrication. This is preferably hydrodynamic and/or hydrostatic. An anti-leakage system (28) blasts air from the exterior against the outward lubricant leakage path. Air is blasted into the region between the edge zone (30) of the flexible roller casing and the associated stationary end component (20), from an annular air chamber (32) which forms the anti-leakage system. It is located in a stationary end component (20), bordering radially against the casing edge zone. A seal (36) carried in rotation by the casing, is located in the annular chamber near the casing edge. Mechanical operating pressure is developed at least partially by the anti-leakage air pressure. The operating pressure is about 8000 Pa. The air contains lubricating oil. Oil is provided to lubricate the region between the pressure shoe and the roller casing. Between the roller interior (40) and the annular air chamber (28) there is a lubricant- or oil-leakage chamber (44). On the lubricant leakage path, there is at least one seal (46) in addition. Casing edges at the prolonged pressing nip (16) are guided in the stationary end components (20), in correspondence with contours of the pressing shoe surface facing the web.