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Abstract

A method for manufacturing a foamed polyurethane molded article, that includes the steps of introducing an expandable polyurethane reactive mixture into a mold and evacuating the mold, expanding the reactive mixture expands so as to fill the mold, and exhausting gases liberated during the expanding step through one or more expansion openings disposed at one or more points of maximum height in a top mold region, each of the expansion openings being closeable by a needle valve disposed in a valve capillary. In addition the method includes sensing a temporal pressure characteristic in the valve capillary, controlling each of the one or more needle valves using the temporal pressure characteristic, so as to close the respective expansion opening in response to a pressure drop occurring when the expanding reactive mixture penetrates into the valve capillary, opening the mold, and ejecting the molded article.

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First Claim