Patent US4294356A successfully refreshed from Google Patents.
US3545207A
Expired / Lapsed
US
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Boiler control system
Assignee: Leeds and Northrup Co
•
Filing: 1969-07-23
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Granted: 1970-12-08
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Expires: 1989-07-23
Abstract
No abstract record available.
Inventors
- 👤 Justus C Barber
- 👤 Theron W Jenkins Jr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 10:44
CPC Classifications
F; F23; F23N; F23N1/00; F23N1/08; F23N1/10; F01; F01K; F01K13/00; F01K13/02; F23N5/00; F23N5/18; F23N2223/00; F23N2223/12; F23N2223/14
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US3388553A
Cited
US3417737A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1973-12-07 | 1974-06-08 | 1974-12-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1977-12-07 | 1978-06-08 | 1978-12-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1981-12-07 | 1982-06-08 | 1982-12-08 | $7700.00 | Window Closed / Lapsed |