ARRANGEMENT IN THE WET END OF A PAPER MACHINE

摘要

An arrangement in the wet end of a paper machine for transferring web from the former to the press section. The former comprises a twin wire zone defined by an upper wire loop (11) and a lower wire loop (10), after which the web (W) follows the upper wire (11) to a transfer point, in which it is transferred from the underside of the upper wire (11) onto the top side of a weave (22) included in the press section. At the end of the twin wire zone, a suction box (17) is provided inside the upper wire loop (11) and facing it, an open roll (18) inside the lower wire loop (10). The lid (17') of the suction box is at least in a run situation curved so that the tension of the upper wire (11) reduces the normal force between the wire (11) and the lid (17') caused by the underpressure of the suction box (17). The underpressure of the suction box (17) keeps the web mainly off from the roll (18) and the lower wire (10) while being adhered to the underside of the upper wire (11) and conforming to the curved shape of the cover (17') of the suction box. In association with the suction box (17) and/or the roll (18) are provided also members (17a, 18') for making the web follow the lower wire (10) in a break situation for conducting it to the broke handling system.