Extruding foamed plastic using horizontal vacuum chamber

摘要

Foam plastic is made by extruding foamable plastic melt into a vacuum chamber and passing it into a body of liq. which is partially within and partially without the chamber, the extrudate exiting the chamber through the body of liq. The level of liq. inside the chamber is controlled by extracting it, i.e., circulating it to the portion without the chamber, the amt. circulated pref. being inversely proportional to the absolute pressure within the chamber.