The present invention relates to an extruder (100) comprising a housing with an inner housing recess, in which an extruder screw with helical extruder screw flights (32, 33, 34) is rotatably mounted. The outer diameter of the extruder screw is subdivided into a diameter start zone, a diameter center zone and a diameter end zone, wherein the diameter center zone has a larger outer diameter than the other diameter zones, and tapered transitions are formed between zones of different diameters. At least one degassing zone (23.2) is formed in the diameter center zone, said degassing zone having a housing recess from which at least one suction port extends to the outside of the housing. The flow channel formed between the extruder screw core and the inner wall of the inner housing recess is designed as an annular expansion nozzle, wherein the outer diameter of the extruder screw flights (32, 33, 34) is constant and the radial flow channel height increases.
Area Code: DE
Application Number: CN202080051827.9
