Press section to extract water from a wet paper/cardboard web has a shoe press roller with two lower press rollers forming two extended roller press gaps with blankets to carry the web in an enclosed path

摘要

The press section to extract water from a web (10), of paper or cardboard, has an upper shoe press roller (20) and two lower press rollers (22,24). The shoe press roller forms two roller press gaps (S1,S2) with the lower press rollers. The web passes with two blankets at least through the first press gap (S1), in the direction (L) of web travel. The web press section has a second and extended press roller gap in the direction of web travel, where the web is carried between two blankets. The web press section uses a maximum of three blankets (14,18,26), to give an enclosed web path through the press assembly. One blanket (14) passes through both extended roller press gaps with the web, formed at the shoe press roller, and around preferably a suction roller (36) for path deflection between the roller press gaps. The blanket also acts as a pick-up blanket. After the second extended roller press gap, the web moves with a lower blanket (26) around preferably a suction deflection roller (30), where the web is separated into a drying station, while the lower blanket is taken off into a downwards path. The flexible mantle (82) of the shoe press roller and/or the mantle of the leading lower press roller forming the first roller press gap and/or themantle of the trailing lower press roller forming the second roller press gap is fitted with grooves and/or blind drillings. The trailing lower press roller can have a smooth mantle surface where the web is with a single blanket. The two lower press rollers can have mantles with grooves and/or blind drillings. The leading lower press roller can be a suction press roller, or both the lower press rollers can be solid. At least one of the lower press rollers is fitted with CARB bearings. At least one of the lower press rollers has a hollow roller mantle with an adjustable bend around a fixed core. The mantle of the shoe press roller has a guide with position stability. The shoe press roller has an outer hollow carrier, secured against rotation at its ends, and an outer flexible rotating roller mantle. Two supports bear against the interior of the hollow mantle at the two roller press gap points against an inner carrier. The mantle supports are press shoes, supported directly at the inner carrier. The support has a direct or linkage connection to the press shoe, to give a variable and independent supporting force. The hollow carrier and the inner carrier are equidistant at both their ends. Each of the lower press rollers have an individual support, with a supporting force equal to the support force within the shoe press roller, to give separate press forces at the two extended roller press gaps. A transfer belt can carry the web through the press section, instead of a lower blanket. A lower blanket can be discarded, so that the web is in direct contact with the surface of the second lower press roller, before its movement to a further press section or a drying station. The press roller in direct contact with the web is fitted with a scraper. The press section is fitted with troughs to take off the extracted water from the web. A steam blower box is mounted at the deflection suction roller between the press gaps.