Apparatus for separating liquid-solid mixtures

An improved apparatus for separating a liquid phase and a particulate solid from a mixture thereof, said apparatus including a support frame, a conveyor screw rotatably mounted to said support frame, means for rotating said conveyor screw, screen means surrounding said conveyor screw for filtering the particulate solid material from the mixture fed to the upstream end of said conveyor screw, and means adjacent the downstream end of the conveyor screw for restricting the flow of solid phase from the space between the screw and the downstream end of said screen means to maintain a selected pressure on the mixture between said screw and said screen means, wherein the improvement comprises:

• said flow restricting means including an extension on the downstream end of said conveyor screw, a housing that encloses said screw extension, said housing including an imperforate cylindrical wall that is coaxial with the axis of rotation of the screw and an end wall that is secured to the downstream end of the cylindrical wall, said screw extension including a cylindrical wall that is concentric with said cylindrical housing wall to thereby form an annular passageway with said cylindrical housing wall that communicates with the space between the screw and said screen means and that terminates at said end wall, at least two paddles secured to said screw extension wall for propelling the solid phase of the mixture forced into said annular passageway in an annular path about said screw extension wall, said paddles being arranged in longitudinally spaced relationship on said screw extension wall, said cylindrical housing wall having a discharge opening formed therein in alignment with said paddles, said opening having a downstream edge relative to the direction of rotation of said paddles, valve means within the said discharge opening for restricting flow through said opening, and at least one stripper member attached to said cylindrical housing wall adjacent said downstream edge of the discharge opening and at a position aligned in the space between the paddles, whereby the stripper member aids in forcing the solid phase propelled by said paddles into said discharge opening.