PSI-Polymer Systems, Inc. Introduces Extrusion Gear Pump Line for PEX Pipe & Tubing Applications Hickory, NC (July, 30 2008)
PSI-Polymer Systems Inc. has introduced a new line of extrusion gear pumps specifically designed for processing cross-linked polyethylene (PEX).
PEX is a commonly used material for producing plumbing pipe and tubing. It offers advantages over more traditional piping materials as it can process hot and cold water, and withstand high pressures. However, because of the cross-linking process, PEX cannot be re-melted and the material typically cures in less than 5 minutes.
Extrusion gear pumps have successfully been used on pipe and tubing applications since the early 1980’s. However, because of the cross-linking process, PEX extrusion has been largely avoided by gear pump suppliers. Gear pump shafts are lubricated by the material the pump is processing, and this material may take several minutes to travel through the bearing journals in the gear pump. Because of this, the PEX material would cross-link between the bearings and shafts in the gear pump, causing the pump to freeze up.
“We welcomed the challenge of engineering and manufacturing an extrusion gear pump for the PEX extrusion market,” said Rob Martin, General Manager of PSI-Polymer Systems Inc. “The material offers significant advantages to pipe manufacturers and end users. Our challenge was to help process it successfully so the processor could realize significant material savings, reduction in scrap, increased output, and ultimately a better end product.”
In 2006, PSI worked with Vanguard Piping Systems (now Viega LLC), and installed a custom designed extrusion gear pump on a PEX pipe extrusion line. After minor adjustments and fine tuning, the pump significantly improved output rates, decreased scrap, improved gauge control, and even reduced gel formation, another obstacle for PEX pipe manufacturers. This successful installation led PSI to commercialize a new line of gear pumps specifically for these types of applications.