Papermaking machine press section to extract water from a wet web has a separation section between the roller press gaps where the blankets and the web move on separate paths

摘要

At the press section of a web production machine, to extract water from the wet web, both press blankets (9,10) pass through both press roller gaps (7,8). Between the roller press gaps (7,8), the two press blankets (9,10) move apart from the web (1) in at least one separation section (11). The running length for the press blankets (9,10) between the press gaps (7,8) is longer than the path for the web (1) between the gaps (7,8). One press blanket (9,10) can be passed through both roller press gaps (7,8), and be separated from the web (1) in at least one section (11) between the gaps (7,8) so that they travel on independent paths. At least one belt, and preferably all belts (9,10) are identical fourdriniers or blankets which absorb water, or they have a different water absorbency and/or surface structure. The two roller press gaps (7,8) are formed by four press rollers (3-6). The paired rollers (5,6) at the second press gap (8) rotate faster than the rollers (3,4) for the first press gap (7), at a speed which is 0.2-3.0% faster and preferably 0.4-1.0%. The two press gaps (7,8) can be formed by three press rollers (3-5), with a center roller. At least one press gap (7,8) can be extended, and preferably both are longer. The belts (9,10) are separated from the web (1) by suction (12) and/or blower units. At the separation section (11), the blankets (9,10) are dried by conditioning units (2).