Patent US3817874A successfully refreshed from Google Patents.
US3817874A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for increasing the surface area of active carbons
Assignee: Standard Oil Co
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Filing: 1972-01-31
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Granted: 1974-06-18
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Expires: 1992-01-31
Abstract
Abstract IMPROVED PROCESS FOR THE PRODUCTION OF ACTIVE CARBONS BY TREATING POROUS CARBON WITH THE OXIDE OR HYDROXIDE OF AN ALKALI METAL OR ALKALINE EARTH METAL, AND SUBJECTING SAID TREATED CARBON TO A SUITABLE ACID ANHYDRIDE AND HEAT TO FORM HIGH SURFACE CARBONS.
Inventors
- 👤 A Wennerberg
- 👤 J Bukvich
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 16:34
CPC Classifications
C; C01; C01B; C01B32/00; C01B32/30; C01B32/354
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-06-17 | 1977-12-17 | 1978-06-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-17 | 1981-12-17 | 1982-06-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-17 | 1985-12-17 | 1986-06-18 | $7700.00 | Window Closed / Lapsed |