Patent US1797248A successfully refreshed from Google Patents.
US1797248A
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US
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Filtering method and apparatus
Assignee: American Anode Inc
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Filing: 1927-07-20
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Granted: 1931-03-24
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Expires: 1947-07-20
Abstract
No abstract record available.
Inventors
- 👤 Szegvari Andrew
- 👤 Charles M Spencer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 11:54
CPC Classifications
B; B01; B01D; B01D33/00; B01D33/06; B01D33/073; B01D33/044
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) | 1934-03-23 | 1934-09-22 | 1935-03-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1938-03-23 | 1938-09-22 | 1939-03-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1942-03-23 | 1942-09-22 | 1943-03-24 | $7700.00 | Window Closed / Lapsed |