Patent US3640846A successfully refreshed from Google Patents.
US3640846A
Expired / Lapsed
US
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Production of methane by bacterial action
Assignee: United States Department of the Interior
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Filing: 1969-04-29
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Granted: 1972-02-08
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Expires: 1989-04-29
Abstract
Abstract A mixture of coal and sewage solids is digested by anaerobic bacteria to produce methane.
Inventors
- 👤 Glenn E Johnson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 08:26
CPC Classifications
C; C12; C12P; C12P5/00; C12P5/02; C12P5/023; Y; Y02; Y02E; Y02E50/00; Y02E50/30; Y10; Y10S; Y10S435/00; Y10S435/801; Y10S435/8215; Y10S435/822; Y10S435/858
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1990523A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-02-07 | 1975-08-09 | 1976-02-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-02-07 | 1979-08-09 | 1980-02-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-02-07 | 1983-08-09 | 1984-02-08 | $7700.00 | Window Closed / Lapsed |