Patent attributes
In a rotary drum for condensing pulp from a pulp slurry vat, the drum including radial conduits delivering filtrate from a pulp mat on an outer surface of the drum to at least one filtrate conduit coaxial with a drum rotational axis, a valve segment in the filtrate conduit including: an outer surface juxtaposed against drainage outlets of the radial conduits as the conduits pass through an angular range extending from an upper drum position to an immersed in a vat position, wherein the valve segment does not block the drainage outlets during a majority of the rotation of the drum; at least one inlet aperture on the outer surface aligned with the drainage outlets, said inlet aperture extending at least a majority of a width of the valve segment, and a closed passage extending from the inlet aperture to a gas vent external to the filtrate conduit, wherein the closed passage is offset from and below a centerline of the filtrate conduit.