Higher filler content saves costs in PVC pipe production

摘要

Manufacturers can significantly reduce feedstock costs for PVC pipe by increasing filler content. The engineering challenge is to guarantee a stable process and consistently good product quality, even for highly filled pipe. Krauss-Maffei, Germany, manufactures 36D twin-screw extruders that have proved successful in processing highly-filled formulations. For PVC wastewater pipe, filler content of up to 65 parts (approximately 40 per cent) chalk (CaCO_3) is feasible. Highly filled pipes with diameters between 50mm and 500mm are used for transporting wastewater. To facilitate processing of highly filled formulations, the extruders have special material feed, weighing and meteringsystems. The PVC CaCO_3 are transported from the storage container to the hopper of the gravimetric metering unit with the help of a'spiral feed screw.