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US1542647A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Calcining method and apparatus
Assignee: Individual
•
Filing: 1922-06-12
•
Granted: 1925-06-16
•
Expires: 1942-06-12
Abstract
No abstract record available.
Inventors
- 👤 Charles F Sparks
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 08:04
CPC Classifications
B; B01; B01J; B01J6/00; F; F27; F27B; F27B17/00
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) | 1928-06-15 | 1928-12-15 | 1929-06-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1932-06-15 | 1932-12-15 | 1933-06-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1936-06-15 | 1936-12-15 | 1937-06-16 | $7700.00 | Window Closed / Lapsed |