Multi-shaft extruder

Multi-shaft extruder consisting of a drive (1) and a process part (5) connected thereto with at least six axis-parallel worm shafts (4) which are disposed in a circle (7) between an exterior housing (9) and an interior housing (10), rotate in the same direction and are non-rotatably connected to interlocking feed screws (11, 12, 13) and other elements, the exterior housing (9) on the inside and the interior housing (10) being provided with axis-parallel, concave circular segments (15, 16) which receive the respective worm shaft (4) and with at least one material supply opening (20) at one end of the exterior housing (9) and at least one material outlet opening (18), characterised in that the drive (1) has two pinion shafts (2) which are partitioned into groups of identical design and disposed on a circle (7), the pinion shafts being radially driven from the inside and from the outside at equal forces and in the same direction and in diametrical opposition and coaxially connected to the worm shafts (4) of the process part (5) via couplings (3), the worm shafts (4) having a feed length (L) of at least six Do and a Do/Di ratio of 1.5 to 1.93, wherein Do is the outside diameter and Di is the inside diameter of the feed screws (11, 12, 13) and the torque density of the extruder is at least 50 Nm/cm3.