Patent US3439474A successfully refreshed from Google Patents.
US3439474A
Expired / Lapsed
US
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Method for hydrogen separation and purification
Assignee: Union Carbide Corp
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Filing: 1967-08-17
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Granted: 1969-04-22
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Expires: 1987-08-17
Abstract
No abstract record available.
Inventors
- 👤 David L Mckinley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 03:18
CPC Classifications
C; C01; C01B; C01B3/00; C01B3/50; C01B3/501; C01B3/503; C01B3/505; C01B2203/00; C01B2203/04; C01B2203/0405; C01B2203/0465; C01B2203/048
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1972-04-21 | 1972-10-21 | 1973-04-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1976-04-21 | 1976-10-21 | 1977-04-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1980-04-21 | 1980-10-21 | 1981-04-22 | $7700.00 | Window Closed / Lapsed |