Werner & Pfleiderer Gmbh

Hans Wobbe

Eberhard Uhland

Gerhard Weihrich

Hellmut Boden

Arno Knoll

A screw-type extrusion machine has a housing with at least one housing bore, in which a screw shaft is arranged. The housing has outer surfaces, which have a non-constant distance to the wall of the at least one bore. The outer surfaces are provided with heating elements. In order to attain an approximately constant temperature along the circumference of the wall of the at least one bore, heating elements of a different specific heating capacity are arranged sectionally on the outer surfaces of the housing, the heating elements being such formed that the heating temperature at the wall of the at least one bore is approximately constant.

Screw-type extrusion machine with heating elements

In the preparation and production of plastic materials by a continuously operating double shaft screw-type extruder, the efficiency of production often depends on good delivery of material to the extruder. In accordance with the invention for processing various types of plastic materials, a primary stage is mounted in a pressure-tight sealed manner on the housing of the extruder, the primary stage being formed by a vertical double conical container in which a pair of screw-type helices are rotatably supported and driven from above. The helices are connected to two replaceable feed elements at their lower ends so that delivery of material to the extruder is achieved without any intermediate dead spaces.

Process and apparatus for two stage treatment of plastic materials

An extruder for processing plastic material has a housing with a longitudinal bore in which an extruder screw is coaxially fitted for rotation around an axis of the screw to advance plastic material through the bore by threads on the screw. A plurality of throttling plungers are slidably supported in rectangular slots in the housing perpendicular to the axis of the screw. The throttling plungers define an inner throttling surface facing an outer thread-free region of the screw to form an annular throttle gap therewith. In order to avoid uncontrolled changes in the throttling system, the throttling surfaces are not concentric with the outer surface of the screw, so that the throttle gap has a width which varies progressively and symmetrically around the screw.

Plastic melt extruder having an adjustable throttling gap of non-uniform

A screw kneader for a plastic material in which a pair of longitudinal screws are rotatably mounted in respective bores for conveying plastic material through the kneader. The screws have spaced portions for advancing the plastic material from an inlet region to an outlet region and between the spaced portions is a section with reversed threads opposing plastic flow to effect mixing of the plastic material. The threads of the intermediate section are provided with openings to permit passage of up to 20% of said plastic material in the direction of advance. Transfer elements with helical threads connect opposite ends of the threads in the intermediate section with the threads of the inlet and outlet regions. The transfer elements of the two screws mutually engage one another to strip plastic material from one another and from the walls of the bores.

Growing community of inventors

Malmsheim, Germany

Hans Wobbe