Patent US2012721A successfully refreshed from Google Patents.
US2194733A
Expired / Lapsed
US
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Air heating furnace
Assignee: Pennsylvania Furnace & Iron Co
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Filing: 1937-09-08
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Granted: 1940-03-26
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Expires: 1957-09-08
Abstract
No abstract record available.
Inventors
- 👤 Christian S Andersen
- 👤 Alfred L Schellhammer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 17:23
CPC Classifications
F; F24; F24H; F24H3/00; F24H3/02; F24H3/06; F24H3/10; F24H3/105; Y; Y10; Y10S; Y10S165/00; Y10S165/355; Y10S165/356; Y10S165/373; Y10S165/384; Y10T; Y10T29/00; Y10T29/49; Y10T29/4935
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) | 1943-03-26 | 1943-09-25 | 1944-03-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1947-03-26 | 1947-09-25 | 1948-03-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1951-03-26 | 1951-09-25 | 1952-03-26 | $7700.00 | Window Closed / Lapsed |