US3915616A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Diverging mandrel extension for extrusion of foamed polymer
Assignee: Phillips Petroleum Co
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Filing: 1974-05-31
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Granted: 1975-10-28
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Expires: 1994-05-31
Abstract
Abstract Cellular polymer extrudates are formed by passing molten polymer containing an expanding agent through a die which allows gradual expansion thereof just before it leaves the die. The extrudate is then drawn over a gradually diverging mandrel extension. The process is particularly applicable to the forming of rigid PVC pipe.
Inventors
- 👤 Ludo C Nackaerts
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 08:43
CPC Classifications
B; B29; B29C; B29C44/00; B29C44/34; B29C44/36; B29C44/46; B29C44/50; B29C44/507; B29C48/00; B29C48/03; B29C48/09; B29C48/25; B29C48/30; B29C48/32; B29C48/001; B29C48/0012; B29C48/0019; B29C48/10; B29K; B29K2105/00; B29K2105/04; B29L; B29L2023/00
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
83 words
Tubular foam extrusion apparatus comprising in combination: an extruder having a die head with a centrally disposed mandrel and a surrounding bushing, said mandrel extending beyond an end of said bushing a distance of 1- 20 times a diameter of said mandrel, said mandrel and surrounding bushing being disposed so that a cross-sectional area of an annulus therebetween gradually increases, said mandrel extending beyond said bushing having smooth straight walls diverging at an angle of 0.1* to 5* toward a downstream end thereof.
Claim 2
Dependent Claim
83 words
Tubular foam extrusion apparatus comprising in combination: an extruder having a die head with a centrally disposed mandrel and a surrounding bushing, said mandrel extending beyond an end of said bushing a distance of 1- 20 times a diameter of said mandrel, said mandrel and surrounding bushing being disposed so that a cross-sectional area of an annulus therebetween gradually increases, said mandrel extending beyond said bushing having smooth straight walls diverging at an angle of 0.1* to 5* toward a downstream end thereof.
Claim 3
Dependent Claim
24 words
Apparatus according to claim 1 wherein said mandrel extending beyond said bushing has smooth straight walls diverging at an angle of 0.25* to 1*.
Claim 4
Dependent Claim
48 words
Apparatus according to claim 1 wherein a ratio of said cross sectional area of said annulus at a face of the die to said cross sectional area of said annulus at a point where said increase in cross sectional begins is within the range of 1.1:1 to 3:1.
Claim 5
Dependent Claim
24 words
Apparatus according to claim 3 wherein said mandrel extending beyond said bushing has smooth straight walls diverging at an angle of 0.25* to 1*.
Claim 6
Dependent Claim
29 words
Apparatus according to claim 1 comprising in addition a sizing sleeve surrounding an end of said mandrel extension and spaced apart axially from said end of said die bushing.
Claim 7
Dependent Claim
22 words
Apparatus according to claim 1 wherein said annulus gradually increases as a result of said mandrel tapering inwardly in a downstream direction.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-10-27 | 1979-04-28 | 1979-10-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-10-27 | 1983-04-28 | 1983-10-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-10-27 | 1987-04-28 | 1987-10-28 | $7700.00 | Window Closed / Lapsed |