Andritz-ahlstrom Oy

Other

Andritz Oy

Ahlstrom Machinery Oy

Harri Qvintus

Pekka Tervola

Olavi E Pikka

Risto A Ljokkoi

Antero Laine

Sami Siik

The present invention relates to the thickening of pulp suspensions. A low consistency pulp suspension is fed to a pre-thickener () through an inlet conduit (). A layer of thickened pulp, formed on a filter surface (), is pushed along the filter surface by a cleaning member to the discharge end of the pre-thickener and is discharged through the outlet (). The cleaning member comprises a rotating shaft (), on which shaft at least one screw thread () is fixed so as to leave a free space between the shaft and the screw thread. Essentially non-thickened pulp is allowed to flow through the apparatus via this space.

Method for the controlled thickening of low consistency fiber suspensions

The present invention relates to the thickening of pulp suspensions. A low consistency pulp suspension is fed to a pre-thickener ( ) through an inlet conduit ( ). A layer of thickened pulp, formed on a filter surface ( ), is pushed along the filter surface by a cleaning member to the discharge end of the pre-thickener and is discharged through the outlet ( ). The cleaning member comprises a rotating shaft ( ) on which shaft at least one screw thread ( ) is fixed so as to leave a free space between the shaft and the screw thread. Essentially non-thickened pulp is allowed to flow through the apparatus via this space.

Apparatus for the thickening of fiber suspensions

A process for washing pulp including a dilution step, an extraction step and a subsequent displacement step. The process further includes the steps of: diluting the pulp; passing the diluted pulp to the extraction step; developing a first filtrate from the extraction step; passing the pulp from the extraction step to the displacement step; developing a second filtrate from the displacement step; segregating the first and second filtrates; providing the second filtrate to the dilution step; providing a determined minimum volume of the first filtrate needed for the dilution step; and eliminating the remaining volume of the first filtrate from further use in the washing of the pulp.

Supply of washing liquid in a fractionating multi-stage washer

A method is provided by which it possible to intensify a cellulose pulp wash without requiring the purchase of additional equipment. In a washing system having a plurality of stages with a filtrate from each stage, the stages in sequence being N, N+1, etc., and each stage including filtrates F.sub.N and F.sub.N+1, etc., part of the filtrate F.sub.N (e.g. about 5-30 %) is combined with all or part of the filtrate for F.sub.N+1 to produce a combined filtrate, and the combined filtrate is fed in washing stage N as wash liquid. The part of the filtrate F.sub.N that is taken for use as wash liquid in stage N is typically from the end of the washing stage N. The process may be repeated for most of the stages of the washing system.

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Glens Falls, NY, United States of America

Harri Qvintus