Patent US1439283A successfully refreshed from Google Patents.
US1439283A
Expired / Lapsed
US
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Heat exchanger
Assignee: MH Treadwell Co Inc
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Filing: 1920-06-10
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Granted: 1922-12-19
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Expires: 1940-06-10
Abstract
No abstract record available.
Inventors
- 👤 Carl P Astrom
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 16:51
CPC Classifications
F; F28; F28D; F28D7/00; F28D7/16; F28D7/163; F28D7/1638; F28D7/1646; Y; Y10; Y10S; Y10S165/00; Y10S165/051; Y10S165/052; Y10S165/06; Y10S165/061
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) | 1925-12-18 | 1926-06-19 | 1926-12-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1929-12-18 | 1930-06-19 | 1930-12-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1933-12-18 | 1934-06-19 | 1934-12-19 | $7700.00 | Window Closed / Lapsed |