US2238439A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Froth flotation process
Assignee: Hercules Powder Co
•
Filing: 1939-07-25
•
Granted: 1941-04-15
•
Expires: 1959-07-25
Abstract
No abstract record available.
Inventors
- 👤 William T Bishop
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 00:20
CPC Classifications
B; B03; B03D; B03D1/00; B03D1/001; B03D1/004; B03D1/01; B03D2201/00; B03D2201/04; B03D2203/00; B03D2203/02; B03D2203/04
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) | 1944-04-14 | 1944-10-14 | 1945-04-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1948-04-14 | 1948-10-14 | 1949-04-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1952-04-14 | 1952-10-14 | 1953-04-15 | $7700.00 | Window Closed / Lapsed |