Abstract: An asphalt roofing material recycling system and method is used to recycle new and used (post consumer) asphalt materials, such as asphalt shingles, rolled roofing and tar paper that may include granules, fibers or other particles. The asphalt material, which may be in bundles, is broken up and separated and then provided to a cooled recycling vessel. Dry ice is added along with the asphalt material to be recycled. The dry ice removes any moisture present and super-cools the material making it brittle and easier to chip and break up. The recycle vessel includes a number of high speed shippers having tulip hear chipping teeth as well as one horizontal mixer element which stirs the material and makes sure all material is ground. The resulting course to fine powder can be separated by screening and stored as power or compressed into bricks or briquettes.

Abstract: The extrusion screw for thermoplastic material comprises a helical thread, having a trapezoidal profile with a flat crest and inclined flanks, the pitch and the width or the root of which remains constant, while the inside diameter of the screw increases from the entry of the screw in the direction of the exit.