Abstract: In the field of continuous mixer apparatus for commingling particulate thermoplastic materials, employing at least one main rotor with a helical profile body configuration, an improved profile for the peripheral threads is provided. It presents a first upstream feed flight having a plurality of Lowenherz profile outer threads and second downstream feed flight having a plurality of screw-type outer threads, both being adjacent and integral with the periphery of the main rotor.

Abstract: In the field of helical bladed rotors, and their sealing assemblies an improved upstream seal for mixer rotors is provided. It includes a bushing-like visco sleeve subassembly, a sleeve shaped metallic liner positioned abutting the visco sleeve; a sleeve-like, visco seal having first and second peripheries, an L-shaped packing seat retainer, all configured to provide a single annular shaped inner chamber in which a single, rope-like packing component serves to minimize hardening of the packing assembly by minimizing feed particulate material leaking into the upstream visco seal.