Patent US3519068A successfully refreshed from Google Patents.
US3519068A
Expired / Lapsed
US
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Heat exchanger assemblies
Assignee: Birwelco Ltd
•
Filing: 1968-02-08
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Granted: 1970-07-07
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Expires: 1988-02-08
Abstract
No abstract record available.
Inventors
- 👤 Peter John Harris
- 👤 Michael John Billington
- 👤 Richard John Wingrove
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 21:13
CPC Classifications
F; F28; F28B; F28B9/00; F28B9/04; F28B9/06; F28B1/00; F28B1/06; Y; Y10; Y10S; Y10S165/00; Y10S165/90; Y10S261/00; Y10S261/11
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1973-07-06 | 1974-01-05 | 1974-07-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1977-07-06 | 1978-01-05 | 1978-07-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1981-07-06 | 1982-01-05 | 1982-07-07 | $7700.00 | Window Closed / Lapsed |