System for biaxial expansion of polymeric pipe

Abstract

The present invention provides an improved system for the biaxial expansion of polymeric pipe. Wherein the system comprises a tie bar, mandrel, and cooling system. In use, the polymeric pipe material is heated to be rendered plastic and biaxially deformable before being conveyed through the system, via the tie bar. Wherein the tie bar contains a plurality of channels for transporting fluid to different portions of the system. The first channel injects fluid over the mandrel, with the mandrel receiving a heated fluid that flows over the mandrel's surface counter-current to the pipe material, to lubricate the mandrel and increase friction between the pipe and the mandrel. The second channel collects the fluid from the mandrel to be reheated and recirculated. The third channel supplies a cooling fluid, consisting of air, to a cooling chamber formed by the rear of the mandrel, a downstream sealing member, and the pipe material between the two, wherein the cooling fluid is injected into the cooling chamber to freeze the material in place and providing sufficient volume to retain the pipe shape as it freezes, with the pressure inside the chamber being controlled by the upstream and downstream pressure regulators controlling the flow of fluid in and out of the cooling chamber, with the used fluid simply being released into the system's surroundings. Wherein the pipe material is pulled over the mandrel to be expanded to the desired dimensions before entering the downstream cooling system to be frozen into shape.

Dependencies are inferred from the claim text.