Patent US1538686A successfully refreshed from Google Patents.
US1538686A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Air preheater
Assignee: Individual
•
Filing: 1924-05-31
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Granted: 1925-05-19
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Expires: 1944-05-31
Abstract
No abstract record available.
Inventors
- 👤 William T Chamberlain
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 17:00
CPC Classifications
F; F23; F23L; F23L15/00; F23L15/02; Y; Y02; Y02E; Y02E20/00; Y02E20/34; Y10; Y10S; Y10S165/00; Y10S165/009; Y10S165/037
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1928-05-18 | 1928-11-17 | 1929-05-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1932-05-18 | 1932-11-17 | 1933-05-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1936-05-18 | 1936-11-17 | 1937-05-19 | $7700.00 | Window Closed / Lapsed |