US2989038A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Device for starting-up once-through boilers
Assignee: Duerrwerke AG
•
Filing: 1957-04-19
•
Granted: 1961-06-20
•
Expires: 1977-04-19
Abstract
No abstract record available.
Inventors
- 👤 Schwarz Ottmar
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 15:11
CPC Classifications
F; F22; F22B; F22B35/00; F22B35/06; F01; F01K; F01K3/00; F01K3/18; F01K3/20; F01K3/22; Y; Y10; Y10S; Y10S122/00; Y10S122/04; Y10S122/05
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2405573A
Cited
US2700353A
Cited
GB693330A
Cited
GB716524A
Cited
US2869517A
Cited
GB762556A
Cited
US2811837A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1964-06-19 | 1964-12-19 | 1965-06-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1968-06-19 | 1968-12-19 | 1969-06-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1972-06-19 | 1972-12-19 | 1973-06-20 | $7700.00 | Window Closed / Lapsed |