Method and apparatus for molding expandable polystyrene

Abstract From the Canadian patent

Abstract of the Disclosure, This invention relates to improvements in molding expandable polystyrene, particularly for molding high density tubular parts, in which the molding tool is made with a sintercore metal on each side of the mold cavity, and which has an internal vacuum chamber external steam jackets, and compressed air means capable of communicating with both the interior vacuum chamber and the exterior steam jacket. The process sequence comprise the steps of (l) applying a vacuum to the inner chamber of the mold, (2) filling the mold with expandable polystyrene beads, (3) charging the jacket with steam said vacuum being maintained in the inner chamber during steps 2 and 3 to …