METERING TECHNOLOGY Sewer pipes can he produced economically with highly filled PVC formulations. Processing of these formulations requires special machinery designs in order to ensure optimum feeding and plasticising of the material. A machine combination comprising a vertical metering unit and a dynamic mixer assures that every highly filled PVC formulation is metered into the extruder precisely and consistently, so that the screw flights are filled 100%, thus achieving optimum plasticising performance.