Abstract: A waste water treatment system comprises a plurality of screens presenting descending flow surfaces and means defining a flow conduit for waste water or sewage arranged below the upper limits of said flow surfaces. The construction of the flow conduit is such to induce an upflow of the waste water by way of openings therein which are constantly open to means which direct the waste water to the upper ends of said screens in a manner to provide a substantially equal volumetric flow to and over each of said screens.

Abstract: Apparatus for separating or classifying the contents of a flowing slurry comprising a descending flow surface having a low profile and associated therewith a relatively low head box, the latter of which is distinguished by a relatively restricted cross sectional area adjacent its top. The flow surface is characterized by screen sections successive of which differ in orientation and profile whereby to produce a compact structure having a high capacity for separation of liquid from a flowing slurry. The design of the head box is such to enable a fast and effective delivery of slurry in spite of the low head provided.

Abstract: A screen element for joining with other like elements in defining a screen surface over which liquid slurry embodying solids may flow for separating and classifying purposes, said screen element being designed to orient in a sense transverse to a slurry flow and having an elongate bar-like form a surface portion of which provides a segment of the screen flow surface, said element being characterized by at least one portion thereof intermediate its ends being laterally offset with respect to said ends, said laterally offset portion being configured to provide that the flow surface portion thereof has a progressively changing width intermediate its ends.

Abstract: Separating and thickening apparatus, particularly advantageous for use in processing pulp, characterized by an apertured duct preferably of U-shape and rectangular cross-section. The duct is distinguished by closely spaced walls and incorporates removable screen segments which are readily accessible and easily replaced. The apparatus is so contrived to enable a highly efficient, high capacity, dewatering or thickening structure which requires no moving parts.