Press gap, to extract water from a wet web, of paper/cardboard/tissue, has compressed air channels in the counter roller mantle to form an air cushion over the web at the press roller mantle recess

摘要

The press gap to extract water from a wet web (1), of paper or cardboard or tissue, is formed between a press unit (5) with a flexible roller mantle (4) and a rotating counter roller (6). The web passes through the press gap together with a continuous air-permeable belt (2) and a continuous water extraction blanket (3). The web is subjected to a gas medium, and preferably compressed air, from the counter roller at the press gap, through channels (8) in the roller mantle to form a compressed air cushion (9). The pressure channels (7) are only filled with a gas when they are at the press gap, to pass through the mantle channels to the web. The press surface has a concave recess (11) where there is no press action.