US2938712A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Air preheater
Assignee: Svenska Flaktfabriken AB
•
Filing: 1956-04-30
•
Granted: 1960-05-31
•
Expires: 1976-04-30
Abstract
No abstract record available.
Inventors
- 👤 Pellmyr Bengt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 17:47
CPC Classifications
F; F28; F28F; F28F9/00; F28F9/26; F23; F23M; F23M20/00; F28D; F28D7/00; F28D7/06; F28F2280/00; F28F2280/02
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
References Cited (Backward Citations)
US2409801A
Cited
US1744452A
Cited
US1787444A
Cited
US1810165A
Cited
US1835046A
Cited
GB472822A
Cited
US2615687A
Cited
US2655138A
Cited
US2729433A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1963-05-31 | 1963-11-30 | 1964-05-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1967-05-31 | 1967-11-30 | 1968-05-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1971-05-31 | 1971-11-30 | 1972-05-31 | $7700.00 | Window Closed / Lapsed |