Patent US3561906A successfully refreshed from Google Patents.
US3561906A
Expired / Lapsed
US
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Centrifugal fan
Assignee: Svenska Flaktfabriken AB
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Filing: 1969-01-31
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Granted: 1971-02-09
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Expires: 1989-01-31
Abstract
Abstract A CASING FOR A CENTRIFUGAL FAN COMPRISING A HOLLOW BOX STRUCTURE HAVING SQUARE CORNERS, ONE END WALL HAVING AN EXHAUST OPENING AT ONE CORNER AND AN ANGULARLY DISPOSED SHIELDING PLATE AT THE OTHER CORNER. THE FAN WHEEL AXIS IS OFFSET FROM THE CENTER OF THE BOX TOWARD SAID SHIELDING PLATE. THE CASING IS PREFERABLY FORMED BY FOUR UNIFORMSIZED BOX-SHAPED ELEMENTS WHICH ARE ABUTTED AND JOINED AS SHOWN IN FIG. 1.
Inventors
- 👤 Karl-Erik Fermer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 20:17
CPC Classifications
F; F04; F04D; F04D29/00; F04D29/40; F04D29/42; F04D29/4206; F04D29/4226; C; C07; C07C; C07C45/00; C07C45/61; C07C45/64
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) | 1974-02-08 | 1974-08-10 | 1975-02-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-02-08 | 1978-08-10 | 1979-02-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-02-08 | 1982-08-10 | 1983-02-09 | $7700.00 | Window Closed / Lapsed |