US3470943A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Geothermal exchange system
Assignee: Imperial Energy Corp
•
Filing: 1967-04-21
•
Granted: 1969-10-07
•
Expires: 1987-04-21
Abstract
No abstract record available.
Inventors
- 👤 Allen T Van Huisen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 18:30
CPC Classifications
F; F24; F24T; F24T10/00; F24T10/10; F03; F03G; F03G4/00; F03G4/074; F24T10/30; Y; Y02; Y02E; Y02E10/00; Y02E10/10; Y10; Y10S; Y10S159/00; Y10S159/902; Y10S203/00; Y10S203/06; Y10S203/11; Y10S203/21
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1056373A
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US1160853A
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US1815618A
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US1967803A
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US2350976A
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US2559253A
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CH257661A
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US3033538A
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US3243359A
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US3173267A
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US3274769A
Cited
US3352107A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1972-10-06 | 1973-04-07 | 1973-10-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1976-10-06 | 1977-04-07 | 1977-10-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1980-10-06 | 1981-04-07 | 1981-10-07 | $7700.00 | Window Closed / Lapsed |