Patent ID: 6533564
Filing Date: 2003-03-18
Classification: B29C

Abstract:
An apparatus for forming a continuous plastic body with a hardened tube of mold material surrounding a molten core of plastic, said apparatus comprising:(a) a molten plastic supply; (b) a pump downstream from said molten plastic supply for providing a molten plastic melt stream, for forming said molten core; (c) a temperature-controlled conduit downstream from said pump for lowering the temperature of said molten plastic melt stream to above its softening point, wherein said temperature-controlled conduit includes at least a first heat zone at the inlet of said conduit and a second heat zone at the outlet of said conduit and the temperature of said temperature-controlled conduit is controlled by a tubular heat exchanger surrounding said conduit; (d) a continuous molder downstream from said pump for receiving said molten plastic melt stream from said pump including a molten mold material supply and a crosshead die for receiving said molten mold material and forming a continuous mold; and (e) a first cooling zone upstream from the discharge of said melt pump and downstream from said die head for cooling said molten mold material below its softening point temperature to form said continuous mold wherein said first cooling zone includes a vacuum chamber for receiving said molten mold material from said crosshead die and expanding the outer wall of said continuous mold outwardly, a calibrator assembly surrounding said continuous mold for controlling the outward expansion of the outer wall of said continuous mold, and a cooling fluid surrounding said molten mold material.