Abstract: Supporting device for a plastic profile (2), in particular for a plastic pipe, in a calibration device which has a supporting region (1), in which it supports the plastic profile (2), wherein the contour (3) in the supporting region (1) is adapted to the contour of the plastic profile (2). According to the invention, provision is made in that the contour (3) in the supporting region (1), in particular the radius (4), can be changed. Furthermore, the invention relates to a process for changing a supporting region of a supporting device, in which the position of one or more series-arranged supporting devices with continuously changeable supporting region are changed as a function of a predetermined theoretical diameter such that the predetermined diameter is produced.

Abstract: An mandrel for extrusion of hollow bodies, such as, polyvinyl chloride (PVC) hard, compact, and foamed pipes, includes an inner collar and an outer collar, and webs radially joining the inner collar and outer collar. The webs can be arranged twisted and/or offset in radial direction.

Abstract: Supporting device for a plastic profile (2), in particular for a plastic pipe, in a calibration device which has a supporting region (1), in which it supports the plastic profile (2), wherein the contour (3) in the supporting region (1) is adapted to the contour of the plastic profile (2). According to the invention, provision is made in that the contour (3) in the supporting region (1), in particular the radius (4), can be changed. Furthermore, the invention relates to a process for changing a supporting region of a supporting device, in which the position of one or more series-arranged supporting devices with continuously changeable supporting region are changed as a function of a predetermined theoretical diameter such that the predetermined diameter is produced.

Abstract: An mandrel for extrusion of hollow bodies, such as, polyvinyl chloride (PVC) hard, compact, and foamed pipes, includes an inner collar and an outer collar, and webs radially joining the inner collar and outer collar. The webs can be arranged twisted and/or offset in radial direction.

Abstract: An mandrel for extrusion of hollow bodies, such as, polyvinyl chloride (PVC) hard, compact, and foamed pipes, includes an inner collar and an outer collar, and webs radially joining the inner collar and outer collar. The webs can be arranged twisted and/or offset in radial direction.

Abstract: An mandrel for extrusion of hollow bodies, such as, polyvinyl chloride (PVC) hard, compact, and foamed pipes, includes an inner collar, an outer collar, and a middle collar, each of the collars being radially joined by webs to the particular adjoining collar. Each interior web and exterior web, relative to the middle collar, can form a web pair, the webs of the web pair being arranged to overlap at least partially in the radial direction in a particular embodiment.

Abstract: An mandrel for extrusion of hollow bodies, such as, polyvinyl chloride (PVC) hard, compact, and foamed pipes, includes an inner collar and an outer collar, and webs radially joining the inner collar and outer collar. The webs can be arranged twisted and/or offset in radial direction.

Abstract: In a method of screening bulk material, a gas is conducted in counterflow to a direction of movement of bulk material for separating the bulk material into a fraction of coarse particles and a fraction of fine particles. In order to limit the amount of coarse particles in the outgoing fraction of fine particles, the amount of coarse particles contained in the fraction of fine particles is measured and compared with a desired value. When encountering a deviation of the measured the amount of coarse particles contained in the fraction of fine particles form the desired value, the energy of gas is so controlled as to match the amount of coarse particles contained in the fraction of fine particles with the desired value.