Patent US3819790A successfully refreshed from Google Patents.
US3819790A
Expired / Lapsed
US
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Multi-step air ring for tubular film process
Assignee: ExxonMobil Technology and Engineering Co
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Filing: 1972-05-08
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Granted: 1974-06-25
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Expires: 1992-05-08
Abstract
Abstract In the extrusion of a thermoplastic resin through a ring die to form a tubular film wherein the film is partially cooled by means of a cooling gas b the tube is drawn over a cooling mandrel, the improvement of using multistepped adjustable rings to direct the cooling gas onto the external surface of the film between the die-gap and the mandrel, thus defining a series of orifices between the rings and the film to effect a gradient in pressure from the die to the mandrel.
Inventors
- 👤 H North
- 👤 G Calderwood
- 👤 C Williamson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 11:53
CPC Classifications
B; B29; B29C; B29C48/00; B29C48/25; B29C48/88; B29C48/90; B29C48/901; B29C48/903; B29C48/03; B29C48/09; B29C48/10; B29C48/885; B29C48/902; B29C48/911; B29C48/9115; B29C48/912; B29C48/919; B29C2948/00; B29C2948/92; B29C2948/92009; B29C2948/92085; B29C2948/92504; B29C2948/92609; B29C48/001; B29C48/0018
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-06-24 | 1977-12-24 | 1978-06-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-24 | 1981-12-24 | 1982-06-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-24 | 1985-12-24 | 1986-06-25 | $7700.00 | Window Closed / Lapsed |