US3401774A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Readily removable exhaust muffler for high vertical exhaust stacks
Assignee: ALFRED R KRAHN
•
Filing: 1966-04-26
•
Granted: 1968-09-17
•
Expires: 1986-04-26
Abstract
No abstract record available.
Inventors
- 👤 Alfred R Krahn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 23:24
CPC Classifications
F; F01; F01N; F01N13/00; F01N13/18; F01N13/1805; F01N13/08; F01N2590/00; F01N2590/08
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2732913A
Cited
US902806A
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US961638A
Cited
US1937990A
Cited
US2446631A
Cited
US2420700A
Cited
US2624598A
Cited
US3237716A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1971-09-17 | 1972-03-18 | 1972-09-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1975-09-17 | 1976-03-18 | 1976-09-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1979-09-17 | 1980-03-18 | 1980-09-17 | $7700.00 | Window Closed / Lapsed |