Extrusion head for expanded plastic tubes
AssigneeSolvay (Societe Anonyme)
InventorsClaude Dehennau, Martine Kaszacs
Life of this patent
Estimating the term…
Abstract
An extrusion head for the manufacture of tubes including at least one layer of expanded plastic by extruding a stream of molten plastic containing a blowing agent through an annular passage cross section made in the extrusion head. The stream of molten plastic containing the blowing agent spreads out circumferentially and welds itself to itself by the recombining of the two stream fronts. The extrusion head is equipped with a special-purpose thermal regulation device allowing the molten plastic containing the blowing agent to be heated or cooled after the stream fronts have recombined.
Claims20
Extrusion head for manufacture of tubes comprising at least one layer of expanded plastic by extruding a stream of molten plastic containing a blowing agent through an annular passage cross section made in the extrusion head and in which the stream of molten plastic containing the blowing agent spreads out circumferentially and welds itself to itself by recombining of two stream fronts, wherein the extrusion head is equipped with a special-purpose thermal regulation device allowing the molten plastic containing the blowing agent to be heated or cooled after the two stream fronts have recombined,
- wherein the annular passage cross section is preceded by an equalizing device which lies after a feed opening of the extrusion head and which is in a form of a toric groove, and
- the special-purpose thermal regulation device is configured to not cool the stream of molten plastic until after the stream of molten plastic has passed through the toric groove.
An extrusion head for manufacturing tubes comprising:
- a first annular passage configured to receive a first stream of molten material;
- a groove configured to receive a second stream of molten material at an inlet, to split the second stream of molten material and to recombine said split second stream of molten material at a recombination portion of said groove, wherein a cross-section of said groove is greater at said inlet than at said recombination portion;
- a second annular passage configured to receive said second stream of molten material from said groove, wherein said first and second annular passages meet each other at a joining portion;
- and
- a thennal regulation device configured to regulate a temperature of said second stream of molten material without cooling said second stream of molten material until after said second stream of molten material has passed through said groove.
Dependencies are inferred from the claim text.