The Dow Chemical Company

Admiral Maschinenfabrik Gmbh

Vincent L Johnson

Kurt Moser

Disclosed is a high-pressure mixing head for the mixing of at least two reactive plastics material components and the foaming of these components, the mixing head comprises a mixing chamber (18) which has opening thereinto nozzle orifices (22; 24; 41) for the plastics material components and a blowing agent, and in which a metering plunger (20) is mounted for reciprocating movement. The mixing chamber (18) opens into a discharge section (16) of greater dimensions which, thus, acts as a stabilizing zone. On the mixing chamber outlet (26), a variable damper element (purging plunger 12; damping plunger 40) is provided which provides for variable restriction of the mixing chamber outlet (26). The damper element greatly reduces the mixing turbulence within the mixing chamber, such that, in combination with the discharge section of greater dimensions, the plastic foam mixture flows out from the mixing head so smoothly that spatter-free foaming even in open molds becomes possible.

High-pressure mixing head

Disclosed is a high-pressure mixing head for the mixing of at least two reactive plastics material components and the foaming of these components, the mixing head comprising a mixing chamber (18) which has opening thereinto nozzle orifices (22; 24; 41) associated with said plastics material components and a blowing agent, and in which a metering plunger (20) is mounted for reciprocating movement. The mixing chamber (18) opens into a discharge section (16) of greater dimensions which, thus, acts as a stabilizing zone. On the mixing chamber outlet (26), a variable damper element (purging plunger 12; damping plunger 40) is provided which provides for variable restriction of the mixing chamber outlet (26). The damper element greatly reduces the mixing turbulence within the mixing chamber, such that, in combination with the discharge section of greater dimensions, the plastic foam mixture flows out from the mixing head so smoothly that spatter-free foaming even in open molds becomes possible.

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Seabrook, TX, United States of America

Vincent L Johnson