US2777679A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Recovering sub-surface bituminous deposits by creating a frozen barrier and heating in situ
Assignee: Svenska Skifferolje AB
•
Filing: 1952-05-20
•
Granted: 1957-01-15
•
Expires: 1972-05-20
Abstract
No abstract record available.
Inventors
- 👤 Ljungstrom Fredrik
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 12:47
CPC Classifications
E; E21; E21B; E21B36/00; E21B36/04; E21B43/00; E21B43/16; E21B43/24; E21B43/2401
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
References Cited (Backward Citations)
US829664A
Cited
GB190820778A
Cited
GB191011890A
Cited
US1342780A
Cited
US1457479A
Cited
GB155732A
Cited
US1661389A
Cited
US1870869A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1960-01-15 | 1960-07-16 | 1961-01-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1964-01-15 | 1964-07-16 | 1965-01-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1968-01-15 | 1968-07-16 | 1969-01-15 | $7700.00 | Window Closed / Lapsed |