Patent ID: 6368547
Filing Date: 2002-04-09
Classification: B29C

Abstract:
Method for producing a hollow plastic section, comprising the extrusion of a hollow section made of thermoplastic material using an extruder which is provided with a die, which die has an inner mandrel for forming a cavity in the plastic section, said die being arranged for extrusion of said plastic section in a substantially horizontal direction, the plastic section being cooled internally by circulating cooling liquid through a compartment, which is filled with cooling liquid, in the cavity of the plastic section, which compartment is delimited by a first sealing plug and a second sealing plug, which sealing plugs are situated downstream of the inner mandrel and at a distance from one another, are attached to the inner mandrel and are adapted to bear against the plastic section in a sealing manner during operation, wherein the first and second sealing plugs are vertically offset from each other, so that a lower sealing plug and an upper sealing plug are obtained and said plastic section passes said first and second sealing plugs at an incline having an angle with respect to the horizontal, whereby the liquid filled compartment has a highest point close to the upper sealing plug, and wherein the method further comprises the use of vent means for discharging from said liquid filled compartment gas or vapour which collects close to said upper sealing plug at said highest point of said liquid filled compartment.