Patent US2293315A successfully refreshed from Google Patents.
US2293315A
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US
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Heating system
Assignee: Spence Engineering Co Inc
•
Filing: 1940-06-28
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Granted: 1942-08-18
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Expires: 1960-06-28
Abstract
No abstract record available.
Inventors
- 👤 Spence Paulsen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 17:35
CPC Classifications
F; F24; F24D; F24D19/00; F24D19/10; F24D19/1003; Y; Y10; Y10T; Y10T137/00; Y10T137/7722; Y10T137/7758; Y10T137/7762; Y10T137/7764; Y10T137/7768; Y10T137/7781; Y10T137/7793; Y10T137/7808; Y10T137/8158; Y10T137/8225; Y10T137/8242
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) | 1945-08-17 | 1946-02-16 | 1946-08-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1949-08-17 | 1950-02-16 | 1950-08-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1953-08-17 | 1954-02-16 | 1954-08-18 | $7700.00 | Window Closed / Lapsed |