Metso Paper Inc.

Valmet Corporation

Timo Pekkarinen

Jouko Hautala

Lauri Verkasalo

Vesa Juutinen

Antti Suonper&auml;

Mari Silanter&auml;

Juha Kinnunen

In a papermaking process, filtering of white water containing fiber material is performed by feeding the white water to a filter on a surface of which a layer of auxiliary pulp has been formed, such that the white water is filtered through the layer of auxiliary pulp and fiber material in the white water remains in the layer of auxiliary pulp. The mixture of auxiliary pulp and fiber material is removed from the filter and is fed to a fractionating screen. The screen separates the mixture into a short-fibered pulp fraction that can be returned to the papermaking process, and a long-fibered pulp fraction that is returned to the filter where it is used as auxiliary pulp to form a layer on the filter surface.

Method and apparatus for recovering fibers from white water of paper mill

A process arrangement for the short circulation in a paper or board machine including stock chests for component stocks, metering pumps for component stocks, cleaning devices, pumps, a headbox and a wire section as well as a system of pipes connecting these elements, together with regulation devices. After the metering pumps, the component stock flows are passed into a closed mixing volume in which the component stocks are mixed and diluted with a first dilution water flow. From this closed mixing volume, the stock is passed in a closed space by a first feed pump of the main line of the process through a screen and a centrifugal cleaner to the suction side of a second feed pump of the main line, where a second dilution water flow is passed to the stock. The second feed pump feeds the stock through a machine screen to the inlet header in the headbox.

Process arrangement for the short circulation in a paper or board machine

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Tampere, Finland

Timo Pekkarinen