US3456730A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process and apparatus for the production of bitumens from underground deposits having vertical burning front
Assignee: Wintershall Dea International AG
•
Filing: 1967-08-22
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Granted: 1969-07-22
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Expires: 1987-08-22
Abstract
No abstract record available.
Inventors
- 👤 Hans Lange
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 17:44
CPC Classifications
E; E21; E21B; E21B33/00; E21B33/02; E21B33/03; E21B33/04; E21B33/0415; E21B34/00; E21B34/06; E21B34/12; E21B43/00; E21B43/16; E21B43/24; E21B43/243; E21B43/30; E21B43/305
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US3024013A
Cited
US3055423A
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US3044546A
Cited
US3242989A
Cited
US3057404A
Cited
US3360044A
Cited
US3344856A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1972-07-21 | 1973-01-20 | 1973-07-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1976-07-21 | 1977-01-20 | 1977-07-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1980-07-21 | 1981-01-20 | 1981-07-22 | $7700.00 | Window Closed / Lapsed |