Patent US4823141A successfully refreshed from Google Patents.
Patent US3516929A successfully refreshed from Google Patents.
US3516929A
Expired / Lapsed
US
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Rotating biological contactor in a combined sewer
Assignee: Allis Chalmers Corp
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Filing: 1968-11-12
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Granted: 1970-06-23
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Expires: 1988-11-12
Abstract
No abstract record available.
Inventors
- 👤 Fredrick M Welch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 23:31
CPC Classifications
C; C02; C02F; C02F3/00; C02F3/02; C02F3/08; C02F3/082; Y; Y02; Y02W; Y02W10/00; Y02W10/10
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1973-06-22 | 1973-12-22 | 1974-06-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1977-06-22 | 1977-12-22 | 1978-06-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1981-06-22 | 1981-12-22 | 1982-06-23 | $7700.00 | Window Closed / Lapsed |