Patent US1987891A successfully refreshed from Google Patents.
US1987891A
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US
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Heat exchange apparatus
Assignee: C H LEACH Co
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Filing: 1934-06-09
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Granted: 1935-01-15
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Expires: 1954-06-09
Abstract
No abstract record available.
Inventors
- 👤 Frederick W Cattanach
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 14:23
CPC Classifications
F; F28; F28D; F28D7/00; F28D7/0058; F28F; F28F9/00; F28F9/02; F28F9/0229; F28F9/0236; F28F9/0239; F28F9/22; F28F2009/222; F28F2009/224; F28F2265/00; F28F2265/16; Y; Y10; Y10S; Y10S165/00; Y10S165/001; Y10S165/008
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) | 1938-01-14 | 1938-07-16 | 1939-01-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1942-01-14 | 1942-07-16 | 1943-01-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1946-01-14 | 1946-07-16 | 1947-01-15 | $7700.00 | Window Closed / Lapsed |