Extrusion method and apparatus

An extrusion device for processing extrudable material, said extrusion device comprising:

• a central extrusion channel for the extrudable material;
• at least two stator means, with each said stator means including a conically tapered portion which tapers in the direction of said central extrusion channel;
• at least one rotor means rotatably positioned between said stator means, with each said rotor means including a conically tapered portion which tapers in the direction of said central extrusion channel;
• and
• at least one feed defile positioned between said rotor means and said stator means and coupled to said central extrusion channel, wherein each said feed defile has a diameter which decreases in the direction of said central extrusion channel;
• wherein each said stator means includes a first element, and a second element connected to said first element by at least one distance piece, with an intermediate space defined between said first and second elements, wherein a heating means is mounted within said intermediate space, and said heating means comprises an induction coil mounted in said intermediate space.

An extrusion device for processing extrudable material, said extrusion device comprising:

• a central extrusion channel for the extrudable material;
• at least two stator means, with each said stator means including a conically widening portion which widens in the direction of said central extrusion channel coupled to a conically tapered portion which tapers in the direction of said central extrusion channel, wherein each said stator means includes a first element, and a second element connected to said first element by at least one distance piece, with an intermediate space defined between said first and second elements and, wherein each said stator means is at least a two-piece stator means with a heating means positioned in said intermediate space formed in said at least two-piece stator means;
• at least one rotor means rotatably positioned between said stator means, with each said rotor means including a conically widening portion which widens in the direction of said central extrusion channel which is coupled to a conically tapered portion which tapers in the direction of said central extrusion channel;
• and
• at least one feed defile positioned between said rotor means and said stator means and coupled to said central extrusion channel, wherein each said feed defile has a diameter which decreases in the direction of said central extrusion channel.

An extrusion device for processing extrudable material, said extrusion device comprising:

• a central extrusion channel for the extrudable material;
• at least two stator means, with each said stator means including a conically widening portion which widens in the direction of said central extrusion channel coupled to a conically tapered portion which tapers in the direction of said central extrusion channel;
• at least one rotor means rotatably positioned between said stator means, with each said rotor means including a conically widening portion which widens in the direction of said central extrusion channel which is coupled to a conically tapered portion which tapers in the direction of said central extrusion channel;
• and
• at least one feed defile positioned between said rotor means and said stator means and coupled to said central extrusion channel, wherein each said feed defile has a diameter which decreases in the direction of said central extrusion channel, wherein each said stator means includes a first element, and a second element connected to said first element by at least one distance piece, with an intermediate space defined between said first and second elements, wherein a heating means is mounted within said intermediate space.

A method for processing extrudable material comprising the steps of:

• a) feeding extrudable material, which is in solid form and includes plastic mixed with fibers or polymer forming fibers to an extrusion device which includes a central extrusion channel, at least two stator means with each said stator means including a conically tapered portion which tapers in the direction of said central extrusion channel, each said stator means includes a first element, and a second element connected to said first element by at least one distance piece, with an intermediate space defined between said first and second elements, at least one rotor means rotatably positioned between said stator means, with each said rotor means including a conically tapered portion which tapers in the direction of said central extrusion channel, and at least one feed defile positioned between said rotor means and said stator means and coupled to said central extrusion channel, wherein said feed defile has a diameter which decreases in the direction of said central extrusion channel, wherein said extrudable material is supplied into a feeding zone of said feed defile from several equally spaced points about the periphery of said rotor means;
• b) melting said extrudable material in a melt zone of said feed defile with a heating means positioned within said intermediate space formed in each said stator means, wherein the pressure is higher within said melt zone than said feed zone;
• c) compressing said extrudable material in a compression zone of said feed defile to a final extrusion pressure which is higher than the pressure with said melt zone;
• and
• d) extruding said material through said central extrusion channel.

An extrusion device for processing extrudable material for forming a multilayer extrusion product, said extrusion device comprising:

• at least three stator means and at least two rotor means, each said stator and said rotor means including a conically tapered portion, and said stator and rotor means being assembled alternately one within the other, wherein conically tapered portions of said rotor means are disposed between said conically tapered portions of said stator means;
• a plurality of annular tapered feed defiles for melting and compressing the extrudable material, each said feed defile being at least partly conically tapered, said feed defiles have the inlet and outlet ends formed between said conically tapered portions of said stator and rotor means, wherein the diameter of said annular feed defiles decreases in the flow direction of the extrudable material;
• at least one feed inlet for solid extrudable material connected to said inlet end of each said annular feed defile;
• a central extrusion channel connected to said outlet end of each said annular feed defile;
• and
• heating means connected to said stator means for heating and melting the extrudable material flowing in the annular feed defiles before said central extrusion channel.