Patent ID: 6869211

Claim:
Extruder with a housing ( 1 ), in which at least one screw ( 2 , 3 ) is pivotally supported, from its screw core ( 4 ) a land ( 5 ) which runs in a helical line protrudes, there being at least one ventilation opening ( 8 ) in the housing ( 1 ), at least in the area of at least one ventilation opening ( 8 ) the land ( 5 ) of the screw ( 2 , 3 ) having an active flank ( 10 ) which is set back at least in areas relative to a radial plane which passes through the outside edge ( 14 ) of the active flank ( 10 ), wherein the active flank ( 10 ) has a radially outside segment ( 17 ) which with the axis of the screw ( 2 , 3 ) encloses an acute angle (W°), and wherein the segment ( 18 , 19 ) of the active flank ( 10 ) which lies radially inside is concavely shaped.