Abstract: The invention relates to a method and a blank for producing a screw-tube conveyor in the form of a cylindrical rotary tube (110) with an internal screw spiral (120) for conveying and mixing a bulk material. To simplify the method and to create even long screw-tube conveyors with small diameters in an relation to their length, it is proposed according to the invention first to produce a one-piece blank, which comprises a base portion in the basic form of a parallelogram and having laterally mounted fins. In a second method step, the fins are then bent, preferably by 90°, with respect to the base portion. In a third method step, the base portion (112) is then bent along bending lines (115i) in such a way that the base portion forms a helical casing portion (111) of the rotary tube (110) and the previously bent-round fins (122) form segments of the screw spiral (120) arranged inside the rotary tube (110). The invention also relates to a screw-tube conveyor produced in this way.

Abstract: The invention relates to a method and a blank for producing a screw-tube conveyor in the form of a cylindrical rotary tube (110) with an internal screw spiral (120) for conveying and mixing a bulk material. To simplify the method and to create even long screw-tube conveyors with small diameters in relation to their length, it is proposed according to the invention first to produce a one-piece blank, which comprises a base portion in the basic form of a parallelogram and having laterally mounted fins. In a second method step, the fins are then bent, preferably by 90°, with respect to the base portion. In a third method step, the base portion (112) is then bent along bending lines (115i) in such away that the base portion forms a helical casing portion (111) of the rotary tube (110) and the previously bent-round fins (122) form segments of the screw spiral (120) arranged inside the rotary tube (110). The invention also relates to a screw-tube conveyor produced in this way.