Abstract: A flange for a screw housing (500) of a double screw extruder, the flange comprising a flange body, and a flange bore formed in the flange body and having a shape of two partially overlapping circles, wherein the flange bore has an inner perimeter corresponding to an outer perimeter of an accommodation chamber for two extruder screws.

Abstract: At least one section of the screw (11) has a wear-protection layer (13) and at least one other section of the screw preferably has an anti-friction layer (18). In a solid rod (11?), abed (12) for the wear-protection layer (13) is first formed, and in this the wear-protection layer (13) is then applied, and finally the interstices (14) between the screw flights (15) are formed. According to the invention, the wear-protection layer (13), for example composed of tungsten carbide, is applied by build-up welding, and the interstices (14) are formed with lateral separation (16, 16?) with respect to the wear-protection layer (13). For production of the anti-friction layer, the dimension of that/those section(s) of the screw (11) where the anti-friction layer, e.g. composed of molybdenum, is to be applied is reduced below specification, while providing lateral separation (19) with respect to the wear-protection layer. The anti-friction layer is then applied in the under-dimensioned region (17).

Abstract: Gear system for driving screws of a twin-screw extruder with two parallel drive shafts (1, 2) of different length, of which the longer drive shaft (1) bears a drive gear wheel (3). The shorter drive shaft (2) has rotationally fixed connection by way of a pinion (6) to three distributor shafts (13, 14, 15), which can be driven from the longer drive shaft (1) by way of an annular gear wheel (20) which has internal teeth (19) and, on the distributor shafts (13, 14, 15), gear wheels (16, 17, 18) intermeshing with these teeth. On the longer drive shaft (1), there is a pinion (5) directly intermeshing with the pinion (6) of the shorter drive shaft (2). In order to achieve good division of the loads, the annular gear wheel (20) also has outer teeth (21) which intermesh with gear wheels (22, 23) of two intermediate shafts (24, 25), which intermesh by way of further gear wheels (26, 27) with the drive gear wheel (3).