Patent US3725197A successfully refreshed from Google Patents.
US3725197A
Expired / Lapsed
US
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Headbox for a papermaking machine containing multiple parallel ducts
Assignee: Sulzer Escher Wyss GmbH
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Filing: 1970-08-11
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Granted: 1973-04-03
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Expires: 1990-08-11
Abstract
Abstract A headbox for a papermaking machine which includes a plate which extends over the width thereof and contains a plurality of parallel ducts, each of which widen in stepwise fashion with the opening angle between each successively larger duct porion being between 100 degrees and 180 degrees. The stock suspension feeds to the headbox plate directly from the supply conduit and is discharged for the parallel ducts to the headbox outlet by an unobstructed flow path.
Inventors
- 👤 H Dahl
- 👤 A Kurz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 03:23
CPC Classifications
D; D21; D21F; D21F1/00; D21F1/02; D21F1/028; D21F1/026
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) | 1976-04-02 | 1976-10-02 | 1977-04-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-02 | 1980-10-02 | 1981-04-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-02 | 1984-10-02 | 1985-04-03 | $7700.00 | Window Closed / Lapsed |