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US137375A
Expired / Lapsed
US
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Improvement in processes for separating gold and silver from base metals
Assignee: —
•
Filing: —
•
Granted: 1873-04-01
•
Expires: 1890-04-01
Abstract
No abstract record available.
Inventors
No inventors recorded.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 16:07
CPC Classifications
C; C22; C22C; C22C3/00; C22B; C22B3/00; C22B3/20; C22B3/44; C22B3/46
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) | 1876-03-31 | 1876-09-30 | 1877-04-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1880-03-31 | 1880-09-30 | 1881-04-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1884-03-31 | 1884-09-30 | 1885-04-01 | $7700.00 | Window Closed / Lapsed |