Sulzer-escher Wyss Limited

Voith Sulzer Papiertechnik Patent Gmbh

Anton Selbherr

Herbert Holik

Herbert Britz

Erich Linck

Harald Selder

Martin Kemper

Thomas Martin

Woflgang Siewert

The process targets the removal of interfering materials from an aqueous fibrous material suspension, especially if this is produced from recycled paper. Thereby interfering materials, such as printing ink particles, small synthetic particles, or sticky contamination, are eliminated by flotation in a particularly advantageous manner. In accordance with the invention, the combination of low-intensity and high-intensity flotation is undertaken, whereby the low-intensity flotation generally works in the gravitational field and the high-intensity flotation in a centrifugal field.

Process for treating a fibrous material suspension using combination of low-intensity and high-intensity flotation

The flotation apparatus removes ink- and contaminant particles from a fiber stock suspension which is produced during the preparation of waste paper. Admixing of air to the fiber stock suspension is accomplished in stepped diffusors. The fiber stock suspension admixed with air, prior to infeed into a flotation container, is guided through a deflection element effective as an impact mixer and followed by a mixing diffusor having a preferred flow direction. This flotation apparatus is especially suited for eliminating disturbing or spurious substances which are present throughout a relatively wide grain size spectrum. A particularly preferred construction uses one or more closed flotation containers, wherein the air effluxing from the flotation foam can be advantageously re-used for aeration of further infed fiber stock suspension.

Floatation apparatus for removal of distrubing substances, especially

The flotation apparatus comprising a container having a free liquid level of the fiber stock suspension which is fed essentially horizontally to the container by at least one infeed device. The infeed device contains at least one aeration element having an outlet cross-section located at a predetermined region which is 100 to 600 mm, preferably 50 to 250 mm, below the liquid level of the fiber stock suspension in the container. Between the end of the aeration element and the discharge mouth or opening of the infeed device which opens into the container there can be arranged an essentially horizontally extending starting path for quieting or stabilizing the flow of the fiber stock suspension. This starting path is provided at its initial region with an ascending cover member at which merges a channel having a free liquid level.

Flotation apparatus for flotation of fibrous stock suspension recovered

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Herbertingen, Germany

Anton Selbherr