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CA1172813A Expired / Lapsed CA ⏱️ 0.0 years remaining

Apparatus for producing multi-walled thermoplastic tubing

Assignee: Individual
•
Filing: 1982-06-16
•
Granted: 1984-08-21
•
Expires: 2002-06-16
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Abstract

Abstract ABSTRACT In an apparatus for producing multi-walled thermoplastic tubing in which the inner and outer tubing walls are continuously formed by extrusion one within the other, the inner tube being urged outwardly into pressing engagement with the outer tube, the mechanism for urging the inner tube outwardly into securement with the outer tube comprises a mandrel mounted coaxially with the die for extruding the inner tube and on the downstream side of it. The mandrel has an outer surface providing a tapered end portion positioned to receive the inner tube as it is extruded, and a generally cylindrical portion positioned to urge the inner tube into securement with the outer tube. To prevent sticking of the thermoplastic material to the mandrel, the outer surface of the mandrel is maintained at a temperature lower than the molding temperature and is transversely ribbed.

Inventors

  • 👤 Manfred A.A. Lupke
  • 👤 Gerd P.H. Lupke

Bibliographic Details

Application Number —
Jurisdiction CA
Data Source google_patents
Last Synchronized 2026-10-31 23:48
CPC Classifications
B; B29; B29C; B29C49/00; B29C49/42; B29C49/48; B29C49/4823; B29C48/00; B29C48/001; B29C48/0013; B29C48/0015; B29C48/0016; B29C48/03; B29C48/09; B29C48/11; B29C48/13; B29C48/16; B29C48/18; B29C48/21; B29C48/25; B29C48/30; B29C48/3001; B29C48/3003; B29C48/303; B29C48/32; B29C48/335; B29C48/88; B29C48/911; B29C48/9115; B29C35/00; B29C35/16; B29C2035/1616; B29C2035/1658; B29C2791/00; B29C2791/004; B29C2791/006; B29C48/0017; B29C48/90; B29C48/904; B29C49/42407; B29C49/42408; B29L; B29L2016/00; B29L2023/00; B29L2023/18; B29L2023/186; B29L2024/00; B29L2024/003; Y; Y10; Y10T; Y10T156/00; Y10T156/10; Y10T156/1002; Y10T156/1007; Y10T156/1016

Claims Analysis

Total Claims: 3
Claim 1
Independent Claim 114 words
An apparatus for producing multi-walled thermoplastic tubing, including an annular extrusion die for extruding an inner tube of thermoplastic material coaxially within an outer tube as the latter is advanced in an axial direction, and a mandrel mounted coaxially with said die, downstream thereof for urging said inner tube outwardly, the mandrel being provided with channels for a cooling fluid to cool its outer surface receiving said inner tube from the die, wherein said outer surface is provided with transverse ribs to press the inner tube in point contact manner, to secure it to the outer tube, to insure high efficient heat transfer and to prevent sticking of the thermoplastic material to said mandrel.
Claim 2
Independent Claim 114 words
An apparatus for producing multi-walled thermoplastic tubing, including an annular extrusion die for extruding an inner tube of thermoplastic material coaxially within an outer tube as the latter is advanced in an axial direction, and a mandrel mounted coaxially with said die, downstream thereof for urging said inner tube outwardly, the mandrel being provided with channels for a cooling fluid to cool its outer surface receiving said inner tube from the die, wherein said outer surface is provided with transverse ribs to press the inner tube in point contact manner, to secure it to the outer tube, to insure high efficient heat transfer and to prevent sticking of the thermoplastic material to said mandrel.
Claim 3
Dependent Claim 32 words
The apparatus of claim 1 wherein said ribs are shaped as a coil of a pipe imbedded in the mandrel, the inner chamber of said pipe representing said channels for cooling fluid,

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