US1751999A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for filtering air
Assignee: Individual
•
Filing: 1927-05-26
•
Granted: 1930-03-25
•
Expires: 1947-05-26
Abstract
No abstract record available.
Inventors
- 👤 John C Hines
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 16:09
CPC Classifications
B; B01; B01D; B01D45/00; B01D45/04; B01D45/08; B01D45/10
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) | 1933-03-24 | 1933-09-23 | 1934-03-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1937-03-24 | 1937-09-23 | 1938-03-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1941-03-24 | 1941-09-23 | 1942-03-25 | $7700.00 | Window Closed / Lapsed |