Patent US1878237A successfully refreshed from Google Patents.
US1878237A
Expired / Lapsed
US
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Electrical purification of water
Assignee: NORTHWEST PAPER Co
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Filing: 1930-04-24
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Granted: 1932-09-20
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Expires: 1950-04-24
Abstract
No abstract record available.
Inventors
- 👤 Walter F Hoffman
- 👤 Gortner Ross Aiken
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 05:52
CPC Classifications
B; B01; B01D; B01D61/00; B01D61/42; B01D61/422; B01D61/423; B01D61/44; B01D61/52
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) | 1935-09-20 | 1936-03-21 | 1936-09-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1939-09-20 | 1940-03-21 | 1940-09-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1943-09-20 | 1944-03-21 | 1944-09-20 | $7700.00 | Window Closed / Lapsed |