Patent US2521830A successfully refreshed from Google Patents.
US2521830A
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US
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Mineral wool furnace
Assignee: Universal Oil Products Co
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Filing: 1946-06-20
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Granted: 1950-09-12
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Expires: 1966-06-20
Abstract
No abstract record available.
Inventors
- 👤 Robert B Collins
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 19:53
CPC Classifications
C; C03; C03B; C03B5/00; C03B5/12; C03B37/00; C03B37/01; C03B37/06; F; F27; F27B; F27B17/00
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1656828A
Cited
US2057393A
Cited
US1904781A
Cited
US2172153A
Cited
US2131599A
Cited
US2178871A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1953-09-11 | 1954-03-13 | 1954-09-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1957-09-11 | 1958-03-13 | 1958-09-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1961-09-11 | 1962-03-13 | 1962-09-12 | $7700.00 | Window Closed / Lapsed |