Extrusion International USA 4-2022

64 Extrusion International 4/2022 PIPE EXTRUSION Belling Machine Forms Rieber Socket in PVC-O Pipes SICA, a manufacturer of plastic pipe processingmachinery, has developed an innovative Rieber belling process, specific for PVC-O pipes (orientedmolecule PVC pipes). At the same operating pressure, these pipes require a wall thickness of about 35 to 40% less than those in PVC-U and allow the construction of water supply pipes up to 25 bar of operating pressure. Because of these and other advantages, PVC-O piping systems are becoming increasingly popular. L ike PVC-U pipes, the PVC-O pipes are joined in a socket. The socket, including the gasket seat, is made in an extrusion line with a special bell- ing machine. In PVC-U pipes, “Anger” type sock- et are used, i.e. with removable and replaceable gaskets, as well as “Rie- ber” type sockets that have a gas- ket already integrated in the belling phase and not removable during the assembly of the pipeline. The Rieber system is popular because during in- stallation the possibility of acciden- tal displacement of the gasket is re- duced and the risks of external water dispersion are lower. The realization of the socket in PVC-O pipe requires different proce- dures than the conventional ones for PVC-U pipes. Up to now, these specif- ic procedures have proved to be in- dustrially applicable only for forming Anger-type sockets. The absence of the Rieber socket joint in the PVC-O piping sector has excluded its ap- plication where the Rieber socket is considered decisive for the operating conditions for laying the pipelines. The innovative and exclusive SICA Rieber belling process for PVC-O pipes changes the scenario and makes the Rieber system possible on belling machines used in bioriented pipe production plants. In fact, the belling machines are able to process both pipes produced and oriented continuously in the extrusion line, but also pipes oriented off-line in a tank. The Rieber SICA belling system is functional in PVC-O pipes that com- ply with all the following technical standards: - European EN 17176 - American ANSI / AWWA C909 and ASTM F1483 - Australian AS / NZS 4441 - Canadians CAN / CSA-B137 - International ISO 16422 It is significant that, aswith thewell- established SICA Starbell belling ma- chines used for making Anger sock- ets, the innovative SICA procedure is applied to pipes up to the maximum molecular orientation required by the standards, including class 500 estab- lished by ISO 16422; a standard that, among all those indicated, imposes the most stringent requirements for resistance to hydrostatic pressure in PVC-O piping systems. The SICA belling machines that implement the Rieber belling process are available in three models based on the dimensions range of the ma- chinable pipe. SICA S.p.A. www.sica-italy.com PVC-O pipe DN315 PN25 ISO 16422 MRS500 with Rieber socket with SICA process