Extruder having two or more screw shafts rotatable in the same sense and at the same speed, wherein the extruder has at least one vent (3.2; 4.2), wherein, in the entry region of this at least one vent (3.2; 4.2), each screw shaft has at least one high-pitch screw element (3.4) having a ratio X of pitch T to inner housing diameter Di (3.3; 4.3) of 1.75 to 15, or has at least one asymmetric screw element (4.4), or has at least one screw element mounted eccentrically on the axis of rotation of the screw shaft, wherein these high-pitch screw elements (3.4) or these asymmetric screw elements (4.4), or these screw elements mounted eccentrically on the axis of rotation of the screw shaft are each immediately adjacent and opposite one another on immediately adjacent screw shafts, wherein the entry region of the at least one vent (3.2; 4.2) is a section of the extruder which, based on the first edge of the vent (3.2; 4.2) in conveying direction (3.8; 4.8), covers (a) 100% of the length of the vent (3.2; 4.2) in conveying direction (3.8; 4.8) and extends counter to conveying direction (3.8; 4.8), and (b) 50% of the length of the vent (3.2; 4.2) in conveying direction (3.8; 4.8) and extends in conveying direction (3.8; 4.8), and from the first edge of the vent (3.2; 4.2) in conveying direction (3.8; 4.8) of the extruder, the at least one high-pitch screw element (3.4) in each case, or the at least one asymmetric screw element (4.4) in each case, or the at least one screw element mounted eccentrically on the axis of rotation of the screw shaft in each case, extends into the vent (3.2; 4.2) for 0% to 50% of the length of the vent (3.2; 4.2), and the at least one high-pitch screw element (3.4) in each case, or the at least one asymmetric screw element (4.4) in each case, or the at least one screw element mounted eccentrically on the axis of rotation of the screw shaft in each case, commences in conveying direction (3.8; 4.8) before the first edge of the vent (3.2; 4.2) in conveying direction (3.8; 4.8) and extends at least to the first edge of the vent (3.2; 4.2) in conveying direction (3.8; 4.8), wherein this at least one high-pitch screw element (3.4) in each case or this at least one asymmetric screw element (4.4) in each case or this at least one screw element mounted eccentrically on the axis of rotation of the screw shaft in each case is followed directly in conveying direction (3.8; 4.8) by at least one low-pitch screw element (3.6) in each case having a ratio X of pitch T to inner housing diameter Di (3.3; 4.3) of less than 1.5. wherein the extruder has at least one vent (3.2; 4.2), wherein, in the entry region of this at least one vent (3.2; 4.2), each screw shaft has at least one high-pitch screw element (3.4) having a ratio X of pitch T to inner housing diameter Di (3.3; 4.3) of 1.75 to 15, or has at least one asymmetric screw element (4.4), or has at least one screw element mounted eccentrically on the axis of rotation of the screw shaft, wherein these high-pitch screw elements (3.4) or these asymmetric screw elements (4.4), or these screw elements mounted eccentrically on the axis of rotation of the screw shaft are each immediately adjacent and opposite one another on immediately adjacent screw shafts, wherein the entry region of the at least one vent (3.2; 4.2) is a section of the extruder which, based on the first edge of the vent (3.2; 4.2) in conveying direction (3.8; 4.8), covers (a) 100% of the length of the vent (3.2; 4.2) in conveying direction (3.8; 4.8) and extends counter to conveying direction (3.8; 4.8), and (b) 50% of the length of the vent (3.2; 4.2) in conveying direction (3.8; 4.8) and extends in conveying direction (3.8; 4.8), and (a) 100% of the length of the vent (3.2; 4.2) in conveying direction (3.8; 4.8) and extends counter to conveying direction (3.8; 4.8), and (b) 50% of the length of the vent (3.2; 4.2) in conveying direction (3.8; 4.8) and extends in conveying direction (3.8; 4.8), and from the first edge of the vent (3.2; 4.2) in conveying direction (3.8; 4.8) of the extruder, the at least one high-pitch screw element (3.4) in each case, or the at least one asymmetric screw element (4.4) in each case, or the at least one screw element mounted eccentrically on the axis of rotation of the screw shaft in each case, extends into the vent (3.2; 4.2) for 0% to 50% of the length of the vent (3.2; 4.2), and the at least one high-pitch screw element (3.4) in each case, or the at least one asymmetric screw element (4.4) in each case, or the at least one screw element mounted eccentrically on the axis of rotation of the screw shaft in each case, commences in conveying direction (3.8; 4.8) before the first edge of the vent (3.2; 4.2) in conveying direction (3.8; 4.8) and extends at least to the first edge of the vent (3.2; 4.2) in conveying direction (3.8; 4.8), wherein this at least one high-pitch screw element (3.4) in each case or this at least one asymmetric screw element (4.4) in each case or this at least one screw element mounted eccentrically on the axis of rotation of the screw shaft in each case is followed directly in conveying direction (3.8; 4.8) by at least one low-pitch screw element (3.6) in each case having a ratio X of pitch T to inner housing diameter Di (3.3; 4.3) of less than 1.5.