US2981082A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Heat exchangers
Assignee: National Research Development Corp UK
•
Filing: 1958-08-25
•
Granted: 1961-04-25
•
Expires: 1978-08-25
Abstract
No abstract record available.
Inventors
- 👤 Sixsmith Herbert
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 06:48
CPC Classifications
F; F28; F28D; F28D17/00; F28D17/04
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
References Cited (Backward Citations)
US1653629A
Cited
US2619813A
Cited
US2626510A
Cited
US2677252A
Cited
US2715820A
Cited
US2724954A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1964-04-24 | 1964-10-24 | 1965-04-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1968-04-24 | 1968-10-24 | 1969-04-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1972-04-24 | 1972-10-24 | 1973-04-25 | $7700.00 | Window Closed / Lapsed |