US2593869A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Air purification device
Assignee: Individual
•
Filing: 1948-07-15
•
Granted: 1952-04-22
•
Expires: 1968-07-15
Abstract
No abstract record available.
Inventors
- 👤 Fruth Hal Frederick
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 06:55
CPC Classifications
B; B03; B03C; B03C3/00; B03C3/34; B03C3/40; B03C3/41
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US617618A
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DE507914C
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US945917A
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US1067974A
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US1357201A
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US1399422A
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US1409901A
Cited
DE425273C
Cited
DE442644C
Cited
GB338796A
Cited
FR816463A
Cited
US2231330A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1955-04-22 | 1955-10-22 | 1956-04-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1959-04-22 | 1959-10-22 | 1960-04-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1963-04-22 | 1963-10-22 | 1964-04-22 | $7700.00 | Window Closed / Lapsed |