A. Ahlstrom Corporation

A. Alhstrom Corporation

Harri T Qvintus

Seppo K Kokkonen

Kaj Henricson

Olavi E Pikka

Erkki E Savolainen

Erkki A Ruuskanen

An appratus for treating medium consistency pulp in connection with different treatment apparatuses, such as washers. According to the prior art the treatment of pulp, for example, the washing process, starts at a low consistency, approximately 1-3% so that it is necessary always to dilute pulp before washing, whereby the water consumption of the plant increases and the need of power in, for example, pumping and in the treatment generally increases. The present invention makes it possible to treat medium consistency pulp, because the feeding means is able to spread the pulp as an even layer on the perforated surface of the treating apparatus.

Apparatus for treating pulp

The present invention relates to a method and an apparatus for washing pulp according to which method the pulp is supplied onto a movable liquid-pervious support surface to form a substantially continuous layer; and washing liquid is supplied to the pulp layer and passed in several successive washing phases through different areas of the layer in such a way that the washing liquid gradually flows in the opposite direction compared with the flow direction of the pulp layer. According to the invention the washing liquid is divided in two or more partial flows which pass alternately through different washing phases in such a way that the washing liquid which in one phase has passed through the pulp layer flows past at least the washing phase preceding it in the flow direction of the pulp layer. The apparatus of the invention preferably includes a rotating cylinder having a casing surface of which serves as the liquid-pervious support surface for the pulp.

Apparatus for washing pulp

An apparatus for treating, e.g., washing or filtering, fiber suspensions having a consistency of 8-20%, the apparatus including at least on rotatable filtering surface, an arrangement for feeding the suspension to a treatment region of the apparatus, and an arrangement for discharging the suspension from the treatment region, the feeding arrangement including at least one pressure chamber for fluidizing the suspension, at least one inlet duct for introducing the suspension to the chamber, and at least one feed duct for transferring the suspension from the pressure chamber to the treatment region.

The present invention relates to a method and an apparatus for washing pulp according to which method the pulp is supplied onto a movable liquid-pervious support surface (2) to form a substantially continuous layer (7); and washing liquid is supplied to the pulp layer and passed in several successive washing phases through different areas of the layer in such a way that the washing liquid gradually flows in the opposite direction compared with the flow direction of the pulp layer. According to the invention the washing liquid is divided in two or more partial flows which pass alternately through different washing phases in such a way that the washing liquid which in one phase has passed through the pulp layer flows past at least the washing phase preceding it in the flow direction of the pulp layer. The apparatus of the invention preferably comprises a rotating cylinder (1) the casting surface (2) of which serves as the liquid-pervious support surface for the pulp.

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Savonlinna, Finland

Harri T Qvintus