Suction roller, for use in a papermaking machine, has a twin-chamber structure and a suction zone defined by sealing bars with an intermediate flow limit to form zones of different vacuum levels

摘要

The suction roller, for use with a web (W) in a papermaking machine, has a twin-chamber structure (50). The leading and trailing ends of the suction zone are separated from the interior (59) of the roller by sealing bars (53,54). The suction zone is divided into two sections as a release zone (RZ) and an adhesion zone (HZ), of different vacuum levels, by a flow limit (65) between the sealing bars. The flow limit is static, at a gap (s) from the inner surface (58) of the suction roller mantle, while the cross section (A) of the flow opening between the sections remains constant.