Dewatering press design for papermaking industry, includes first pressing roller with suction capability, against further roller wrapped by dewatering belt

摘要

The first (3) of two or more pressing rollers (3, 4) is implemented for suction. This roller (3), together with a further pressing roller (7) forms preferably the first nip of the pressing arrangement. The further roller (7) is wrapped by a water-absorbent, continuously-recirculating dewatering belt (12). Two pressing components (5, 6) of the central roller (2) lie on a pressing line (18) running approximately through the central roller axle (17). The angle between the pressing components (5, 6), about the central roller axle, is preferably about 120[deg]. Between two pressing nips, the central roller belt (8) is guided by least one guide roller (19) (or other guide components). A heater, especially a steam box (16), heats the web near the guide roller (19). A further, similar heater is located near the first pressing roller (3). Following the pressing arrangement, the central roller belt transfers the web onto the belt (14) of a following unit, preferably an additional pressing arrangement or dryer. The central roller belt is implemented as a water-absorbent dewatering belt, or as a smooth, preferably-impermeable transfer belt. At least a few, and preferably all pressing components (5, 6) of the central roller (2) have a concave pressing surface forming an elongated pressing nip. To modify an existing similar pressing arrangement, the central roller (2) is replaced by a flexible roller casing, pressed by separate components (5, 6) against opposed pressing rollers (3, 4). An independent claim IS INCLUDED FOR the corresponding method of modifying an existing dewatering press arrangement.