Wire section and method of dewatering a fiber web in a wire section web

US6027612A · kind A · utility

Assignee

• Voith Sulzer Papiermaschinen GmbH · DE

Inventors

• Ulrich Begemann · Leonberg, DE
• Gerhard Kotitschke · Steinheim, DE
• Hans Dahl · Ravensburg, DE
• Volker Schmidt-Rohr · Heidenheim, DE
• Karl Josef Böck · Heidenheim, DE

Key dates

• Filing date: Sep 11, 1997
• Grant date: Feb 22, 2000
• Expiry date: Sep 11, 2017

Classification

• Technology area (CPC D): Textiles; Paper
• CPC primary: D21F9/003
• WIPO field: Textile and paper machines
• WIPO sector: Mechanical engineering

Abstract

The invention concerns the wire section of a papermaking machine and a method of removing water from a fiber web in that section. A fiber suspension is discharged from a headbox on at least one and usually between two wires in the forming section. The fiber suspension is dewatered until it eventually reaches the point of immobility at which the fiber orientation is fixed. The rate of removal of water transverse to the direction of travel of the web is controlled at regions across the web. In particular, the rate of water removal is decreased at the edge regions of the wire and the web, as compared with the center region, to improve the transverse formation profile of the web. Various techniques for controlling the rate of water removal are disclosed including using different mesh of the wire at the edge regions and at the center region, a suction forming roll applying different levels of suction at different zones across the wire and the web, and adjustable ledges engaging one of the two wires and being adapted or adjusted to apply different pressure levels to the wire across the web.