Bayer Aktiengesellschaft

Bayer Technology Services Gmbh

Dieter Mrotzek

Wolfgang Bender

Bernd Koglin

Detmar Redeker

Ulrich Esser

Sebastian Jürgen

Karl-Heinz Steiner

The solid bowl screw centrifuge consists of a housing (1) in which a drum (2) is rotatable. A rotatably mounted conveyor screw (3) is situated inside the drum (2). The drum (2) and screw (3) rotate at slightly differing speeds of rotation when in operation. The housing (1) is cylindrical in the region of the clarifying part (I) and conical in the region of the demoisturizing part (II). The suspension inflow (5,6) opens into the hollow screw core (12) at a location between the clarifying part (I) and the demoisturizing part (II). The liquid discharge consists of an overflow weir (16) or stripping pipe (9) on the clarifying part (I). The solids discharge (4) is situated at the end of the demoisturizing part (II). The screw (3) is arranged within the clarifying part (I) on the cylindrical hollow screw core (12) whose peripheral surface is partly or completely equipped with an after-clarifying device through which fluid flows in a radial direction. The after-clarifying device consists either of a filtration device placed on the perforated screw core (12) or of a laminar separator (14). These fittings enable the degree of separation of the centrifuge to be improved, especially in the treatment of solids which sediment only slowly.

Solid bowl centrifuge with terminal clarification device

The screw centrifuge has a cylindrical clarifying part and a conical desiccating part which is provided with axial supply pipes for a washing liquid and with openings for the passage of the washing liquid into the chamber between the drum and the screw core. A substantial improvement in the washing effect is achieved in that the openings are connected to a liquid distributor which is positioned along a cylindrical helix and which charges the washing liquid regularly along the screw flank over at least one turn in the vicinity of the screw core. The liquid distributor either comprises an overflow channel which is positioned in or directly upstream of the screw flank, or it is formed from a compact series of nozzles which are directed at the screw flank. It is an essential feature of this arrangement that the solids which are pushed up by the screw flanks are covered and saturated regularly with the washing liquid.

Screw centrifuge with a washing device

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Leverkusen, Germany

Dieter Mrotzek