A. Ahlstrom Corporation

Cae Investments B.v.

Timo Alajaaski

Risto A Ljokkoi

Antero Laine

Kalevi Laakso

Kaj Henricson

Olavi E Pikka

Markku A Simola

Frank Aaltonen

Pertti Wathen

Screen cylinder or plate having a grooved first face and a stepless

A fiber suspension, such as an in a pulp mill, is treated in an manner which minimizes both the investment and the operating costs associated with a screening plant. A single pump has an outlet connected to a knotter and primary and secondary screening states so that the pump provides substantially the sole motive force to the pulp moving it through the knotter and screening stages. The knotter and screening stages are provided in a common housing with the knotter vertically above the screening stages, and the screening stages one above the other. A single motor may be provided to rotate rotatable elements associated with the knotter and screening stages. The knotter may be connected to a knot washer external of the housing by a valved conduit less than two meters in length, and the secondary screening stage can be connected to a tertiary screening stage exterior of the housing by a valved conduit less than two meters long. Rejects from the knot washer and secondary screening stage may be recycled to the pulp inlet, and dilution water may be introduced where necessary.

Method and apparatus for screening fibrous suspensions

Apparatus for treating fiber suspension

Growing community of inventors

Kotka, Finland

Timo Alajaaski