Andritz Inc.

Ahlstrom Machinery, Inc.

Andritz-ahlstrom Inc.

John Pietrangelo

Joseph R Phillips

Jerry R Johanson

Jay K Sheerer

Mark D Barrett

Victor L Bilodeau

Brian F Greenwood

John D Weston

Ronald G Bain

A comminuted cellulosic fibrous material treatment vessel assembly includes a substantially vertical vessel having a top, bottom, and outlet, and through which the material flows in a flow direction. The vessel preferably has a substantially cylindrical wall with at least one diameter-changing transition between the inlet and the outlet. A screen assembly is preferably provided at or just past the transition. The screen assembly comprises one or more annular screen surfaces diverging in the flow direction of the material, the angle of divergence being between about 0.5-10&#xb0; to the vertical, and preferably substantially continuous. Providing such a screen assembly reduces the radial compression of material thereon, and increases the volume and rate of liquid that can flow through the material and be removed through the screen surface compared to a non-diverging screen surface (that is a right-cylindrical surface). The screen surface has openings of substantially uniform size, and preferably with a substantially uniform percentage of open area, in the flow path.

Method of treating material in a continuous digester

A comminuted cellulosic fibrous material treatment vessel assembly includes a substantially vertical vessel having a top, bottom, and outlet, and through which the material flows in a flow direction. The vessel preferably has a substantially cylindrical wall with at least one diameter-changing transition between the inlet and the outlet. A screen assembly is preferably provided at or just past the transition. The screen assembly comprises one or more annular screen surfaces diverging in the flow direction of the material, the angle of divergence being between about 0.5-10&deg; to the vertical, and preferably substantially continuous. Providing such a screen assembly reduces the radial compression of material thereon, and increases the volume and rate of liquid that can flow through the material and be removed through the screen surface compared to a non-diverging screen surface (that is a right-cylindrical surface). The screen surface has openings of substantially uniform size, and preferably with a substantially uniform percentage of open area, in the flow path.

A comminuted cellulosic fibrous material treatment vessel assembly includes a substantially vertical vessel having a top, bottom, and outlet, and through which the material flows in a flow direction. The vessel preferably has a substantially cylindrical wall with at least one diameter-changing transition between the inlet and the outlet. A screen assembly is preferably provided at or just past the transition. The screen assembly comprises one or more annular screen surfaces diverging in the flow direction of the material, the angle of divergence being between about 0.5-10.degree. to the vertical, and preferably substantially continuous. Providing such a screen assembly reduces the radial compression of material thereon, and increases the volume and rate of liquid that can flow through the material and be removed through the screen surface compared to a non-diverging screen surface (that is a right-cylindrical surface). The screen surface has openings of substantially uniform size, and preferably with a substantially uniform percentage of open area, in the flow path.

Tapered screen assembly for a cellulose pulp digester

A chip bin construction, ideally suited for bins having a maximum diameter of twelve feet or more, uniformly discharges chips, after steaming, without the necessity of a vibratory discharge. A hollow transition portion is provided between a hollow substantially right circular cylindrical main body and a rectangular discharge. The hollow transition may have a substantially circular cross-section open top and a substantially rectangular cross-section open bottom and opposite non-vertical gradually tapering side walls. At least one feed screw may be mounted at the open bottom of the transition for cooperation with the discharge, and the feed screw(s)--or the equivalent--may provide for metering of the chips. Alternatively, the hollow transition portion may provide one dimensional convergence and side relief, and no screw feeders need be provided, in which case a conventional chip meter is used.

Chip feed system

Located within the annular screen of the pressure diffuser is a tubular baffle hung from adjacent the top of the vessel. The baffle has two headers disposed on its inner surface, with openings in the tube providing communication between the exterior of the tube and the headers. A conduit extends from each header to an arm at the top of the vessel, to allow extracted liquid to be discharged. Another extraction conduit is provided at the bottom of the vessel, in communication with the screen interior and the tubular baffle interior. Treatment liquid, such as wash liquid, may be introduced at two, three, or more positions along the vessel with the liquid extracted from the first and second headers being introduceable at different positions along the vessel. A flexible, elastomeric material, sealing element with integral annular skirt may extend from the bottom end of the tubular baffle and engage the screen to provide a seal minimizing mixing between stages.

Growing community of inventors

Queensbury, NY, United States of America

John Pietrangelo