US3438728A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Two-stage regeneration of absorbent for sulfur oxides
Assignee: Boeing North American Inc
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Filing: 1967-05-15
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Granted: 1969-04-15
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Expires: 1987-05-15
Abstract
No abstract record available.
Inventors
- 👤 Le Roy F Grantham
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 11:23
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/34; B01D53/46; B01D53/48; B01D53/50; B01D53/507; Y; Y10; Y10S; Y10S423/00; Y10S423/09; Y10S423/12
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) | 1972-04-14 | 1972-10-14 | 1973-04-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1976-04-14 | 1976-10-14 | 1977-04-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1980-04-14 | 1980-10-14 | 1981-04-15 | $7700.00 | Window Closed / Lapsed |