Patent US2890754A successfully refreshed from Google Patents.
US2890754A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for recovering combustible substances from subterraneous deposits in situ
Assignee: Svenska Skifferolje AB
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Filing: 1954-01-04
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Granted: 1959-06-16
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Expires: 1974-01-04
Abstract
No abstract record available.
Inventors
- 👤 Hoffstrom Nils Ake
- 👤 Eurenius Malte Oscar
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 15:34
CPC Classifications
E; E21; E21B; E21B36/00; E21B36/02
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
62 words
AN APPARATUS FOR RECOVERY OF VALUABLE PRODUCTS FROM A SUB-SURFACE GEOLOGICAL DEPOSIT BY HEATING OF SAID DEPOSIT IN ITS NATURAL CONDITION IN THE GROUND, COMPRISING SPACED OUTER AND INNER IMPERFORATE TUBES CLOSED AT THEIR LOWER ENDS DEFINING AN ANNULAR COMBUSTION CHAMBER THEREBETWEEN AND ADAPTED TO BE INSERTED INTO A BORE HOLE IN SAID DEPOSIT, BURNERS MOUNTED ON SAID INNER TUBE IN SPACED
Claim 2
Independent Claim
62 words
AN APPARATUS FOR RECOVERY OF VALUABLE PRODUCTS FROM A SUB-SURFACE GEOLOGICAL DEPOSIT BY HEATING OF SAID DEPOSIT IN ITS NATURAL CONDITION IN THE GROUND, COMPRISING SPACED OUTER AND INNER IMPERFORATE TUBES CLOSED AT THEIR LOWER ENDS DEFINING AN ANNULAR COMBUSTION CHAMBER THEREBETWEEN AND ADAPTED TO BE INSERTED INTO A BORE HOLE IN SAID DEPOSIT, BURNERS MOUNTED ON SAID INNER TUBE IN SPACED
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1962-06-15 | 1962-12-15 | 1963-06-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1966-06-15 | 1966-12-15 | 1967-06-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1970-06-15 | 1970-12-15 | 1971-06-16 | $7700.00 | Window Closed / Lapsed |