Extruder

An extruder comprising:

• a housing having an inner wall, and
• at least two axially parallel shafts, the shafts being driven in a common direction and provided with at least two flight conveying elements, the at least two flight conveying elements intermeshing in a cross-section perpendicular to the shafts so as to strip each other at an axial distance (Ax) with a small clearance over an entire circumference, the at least two axially parallel shafts being in the housing at a distance (a) between a comb of at least one further flight and the inner wall of the housing, and
• wherein each conveying element has at least two conveying sections rotated through an angle, wherein each conveying section has an axial length (Ls) corresponding to at most ½ times an outer diameter (Da) of the conveying element;
• wherein the distance (a) is greater than a clearance distance (a′) of a flight stripping the inner wall of the housing;
• wherein the flight stripping the inner wall of the housing has a flight depth (b) that is greater than a flight depth (c) associated with the at least one further flight;
• and
• wherein one conveying section is offset relative to the next conveying section by an angle of no greater than 360° /number of flights.