US3452720A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Heat storage heat exchanger
Assignee: Hooker Chemical Corp
•
Filing: 1966-11-07
•
Granted: 1969-07-01
•
Expires: 1986-11-07
Abstract
No abstract record available.
Inventors
- 👤 Willis Thompson Lawrence
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 15:32
CPC Classifications
F; F28; F28D; F28D7/00; F28D7/08; F28D20/00; F28D20/02; F28D20/021; Y; Y02; Y02E; Y02E60/00; Y02E60/14
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US681722A
Cited
US967961A
Cited
US1839392A
Cited
US2808494A
Cited
US2878644A
Cited
US2936741A
Cited
US3163209A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1972-06-30 | 1972-12-30 | 1973-07-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1976-06-30 | 1976-12-30 | 1977-07-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1980-06-30 | 1980-12-30 | 1981-07-01 | $7700.00 | Window Closed / Lapsed |