Importance

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Abstract

An apparatus is provided for the defibration and conditioning of nonflowable cellulosic material, comprising a housing having an inlet and an outlet and a flow chamber for cellulose material therebetween; two screws disposed in the chamber and extending from the inlet to the outlet, the screws having interdigitating helical blades with opposed pitches, and helical grooves therebetween receiving the helical blades of the opposite screws; the screws being arranged for interdigitating rotational movement in opposite directions, so as to defibrate and condition cellulosic material in the bite therebetween while carrying the material through the flow chamber from the inlet towards the outlet; at least a portion of the outer periphery of each helical blade being undulating in a plurality of successive recesses and projections, intermeshing short of contact with a like plurality of projections and recesses defining a land area in the groove of the opposite blade of the other screw, so that within the land areas in the bite of the screws the intermeshing projections of one groove occupy at least part of the recesses in the blade of the other screw to extend the filled-in area of the blade surface along each screw, for improved screw efficiency in defibration and conditioning of the cellulosic material, and transport of the material through the flow chamber.

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First Claim