Patent US2990580A successfully refreshed from Google Patents.
US2990580A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for improving bursting strength of polyethylene pipe
Assignee: EIDP Inc
•
Filing: 1956-06-04
•
Granted: 1961-07-04
•
Expires: 1976-06-04
Abstract
No abstract record available.
Inventors
- 👤 Foster Samuel Phillip
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 07:40
CPC Classifications
B; B29; B29C; B29C71/00; B29C71/02; B29C35/00; B29C35/02; B29C35/04; B29C35/041; B29C2035/042; B29C2035/044; B29C2071/022; B29C35/049; B29K; B29K2023/00; B29K2023/04; B29K2023/06; B29L; B29L2023/00; B29L2023/22
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
93 words
IN A PROCESS FOR INCREASING THE BURSTING STRENGTH OF EXTRUDED POLYETHYLENE PIPE, THE STEPS WHICH COMPRISE EXTRUDING POLYETHYLENE PIPE FROM A MELT OF THE POLYMER, QUENCHING THE EXTRUDED POLYMER TO A SHAPE STABLE FORM SO THAT THE EXTERIOR IS LONGITUDINALLY STRAINED, THEREAFTER HEATING THE EXTERNAL SURFACE OF THE POLYMER TO A TEMPERATURE AND FOR A TIME SUFFICIENT TO RELAX THE OUTER SURFACE OF THE POLYMER WHILE MAINTAINING AND STABILIZING THE PIPE SHAPE DURING THE SURFACE HEAT TREATMENT BY THE RELAXED PORTION OF THE POLYMER SITUATED CLOSE TO THE INNER SURFACE OF THE PIPE.
Claim 2
Dependent Claim
93 words
IN A PROCESS FOR INCREASING THE BURSTING STRENGTH OF EXTRUDED POLYETHYLENE PIPE, THE STEPS WHICH COMPRISE EXTRUDING POLYETHYLENE PIPE FROM A MELT OF THE POLYMER, QUENCHING THE EXTRUDED POLYMER TO A SHAPE STABLE FORM SO THAT THE EXTERIOR IS LONGITUDINALLY STRAINED, THEREAFTER HEATING THE EXTERNAL SURFACE OF THE POLYMER TO A TEMPERATURE AND FOR A TIME SUFFICIENT TO RELAX THE OUTER SURFACE OF THE POLYMER WHILE MAINTAINING AND STABILIZING THE PIPE SHAPE DURING THE SURFACE HEAT TREATMENT BY THE RELAXED PORTION OF THE POLYMER SITUATED CLOSE TO THE INNER SURFACE OF THE PIPE.
References Cited (Backward Citations)
US2205449A
Cited
US2325060A
Cited
US2431042A
Cited
US2632921A
Cited
US2648097A
Cited
US2753596A
Cited
US2763029A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1964-07-03 | 1965-01-02 | 1965-07-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1968-07-03 | 1969-01-02 | 1969-07-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1972-07-03 | 1973-01-02 | 1973-07-04 | $7700.00 | Window Closed / Lapsed |