Moulding articles from prefoamed polystyrene beads - in a mould having walls which are heated and cooled by appropriate medium

摘要

Prefoamed resin beads are introduced into a mould cavity defined by separable wall portions of the mould. The mould has a chamber defined exteriorly of and associated with each wall portion with a heating medium introduced into the chamber to heat the corresponding wall portion, and a cooling medium introduced into the chamber to cool the wall portion when needed. Steam, condensate, and cooling water can be removed from the chamber. A number of nozzles are provided in at least one of the wall portions of the cavity with tubes connecting the nozzles to a manifold located in the chamber, each nozzle being flush with the inner wall of the cavity and so small as to prevent marking of the moulding produced in the cavity. Pressurised heating medium being introduced into the manifold for injection into the cavity to expand the prefoamed beads with the manifold having an arrangement to provide controlled discharge of steam or condensate from the manifold.