Voith Sulzer Papiertechnik Patent Gmbh

Voith Sulzer Papiermaschinen Gmbh

Dirk Thomas

Ulrich Begemann

Wolfgang Griech

Device and process for controlling or regulating a basis weight of a web in a web manufacturing process of a web producing machine. The device includes a first control circuit, adapted to adjust the basis weight, that includes at least one adjustable device for influencing the basis weight and at least one basis weight sensor. A second control circuit having at least one sensor for detecting a concentration of incoming backwater is also provided. The process includes measuring the basis weight of the material web, adjusting the basis weight of the web with a first control device having at least one device for influencing the basis weight, detecting a retention change in a second control circuit, and counteracting the retention change by influencing a concentration of a stock suspension placed one of onto a wire and between wires.

Process for controlling or regulating the basis weight of a paper or cardboard web

Process and apparatus for improving a consistency cross-direction profile of a fiber web in the wet section. The process includes distributing a fiber suspension across a machine width from a headbox to one of on a wire and between two wires, adjusting a cross-sectional basis weight by sectionally mixing, across the machine width, a first suspension having a first solid content and a first percentage composition and a second suspension having second solid content that is one of lower and higher than the first solid content, and a second percentage composition of the solids content of the second suspension differs from the first percentage composition, and sectionally admixing at least a third suspension across the machine width, the third suspension having a solids content that is one of lower and higher than the solids content of at least one of the first and second solids content, and having a third percentage composition that differs from at least one of the first and second percentage compositions. The apparatus includes one of a first machine-wide feed and a first set of individual feeds for the first suspension, a second set of individual feeds for the second suspension, control devices coupled to the second set of individual feeds for regulating a flow of the second suspension, a turbulence generator, a headbox nozzle. At least a third set of individual feeds for a third suspension is positioned at least one of upstream from the turbulence generator and to act equally on each section across the machine width. The third suspension has a solids content that differs from the solids contents of the first and second suspensions, and additional control devices coupled to the third set of individual feeds for regulating a flow of the third suspension.

Process and headbox system for improving consistency cross-direction profile of fiber web

A wet part of a paper making machine includes a distributor to which a main stream of a stock suspension is fed and which has a number of connections. The connections are connected by means of split stream lines to a machine-wide flow box which has a machine-wide slice nozzle (headbox). The split stream lines are connected (directly or indirectly) to the flow box. The slice nozzle is connected to at least one continuous web-forming screen. At least one collection trough is connected to the screen, as well as, optionally, to a backwater tank to accept the backwater trapped by the collection trough. Dilution water lines are provided to introduce backwater into the split stream lines to adjust the stock density of the split streams. The dilution water lines are connected directly to the collection trough.

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Heidenheim, Germany

Dirk Thomas