US3791918A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Headbox of a paper making machine having multiple, vertically inclined vanes
Assignee: Valmet Montreal Inc
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Filing: 1972-03-08
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Granted: 1974-02-12
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Expires: 1992-03-08
Abstract
Abstract In a headbox of a paper making machine flow resistance is used to provide a pressure drop required for rendering uniform the flow velocity profile and for homogenizing paper pulp slurry. The flow resistance is produced by employing vanes extending parallel to the flow and dividing the headbox into flow channels having a small cross sectional area and a large friction surface area. The invention is particularly characterized in that the vanes are inclined in relation to a vertical plane and have vertical extensions. The vanes are spaced apart a distance such that the height of each flow channel is substantially greater than the width.
Inventors
- 👤 J Koskimies
- 👤 K Heinanen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 18:33
CPC Classifications
D; D21; D21F; D21F1/00; D21F1/02; D21F1/026
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
70 words
In a paper making machine, a headbox having a top wall and a bottom wall and side walls, and including vanes extending from the top wall to the bottom wall and dividing the interior of the headbox into a plurality of flow channels, said vanes being inclined to a vertical plane, said vanes being spaced apart such that the height of each flow channel is substantially greater than its width.
Claim 2
Dependent Claim
70 words
In a paper making machine, a headbox having a top wall and a bottom wall and side walls, and including vanes extending from the top wall to the bottom wall and dividing the interior of the headbox into a plurality of flow channels, said vanes being inclined to a vertical plane, said vanes being spaced apart such that the height of each flow channel is substantially greater than its width.
Claim 3
Dependent Claim
49 words
A headbox in accordance with claim 1, comprising spacers, said vanes consisting of sheet material and having planar bends fixed in spaced relationship to said spacers to form said vanes, said spacers constituting the top wall and bottom wall of each flow channel extending parallel to a horizontal plane.
Claim 4
Dependent Claim
43 words
A headbox in accordance with claim 2, comprising tie bolts extending the entire width of the headbox through said side walls, said spacers and said planar bends, said spacers and said planar bends constituting the bottom wall and top wall of the headbox.
Claim 5
Dependent Claim
38 words
A headbox in accordance with claim 2, comprising inner partitions connected with said vanes and extending parallel to the horizontal plane, said partitions dividing said flow channels in the vertical direction into a plurality of additional flow channels.
Claim 6
Dependent Claim
21 words
A headbox in accordance with claim 4, wherein said inner partitions consist of folded bends constituting parts of the vane sheets.
Claim 7
Dependent Claim
20 words
A headbox in accordance with claim 1, comprising an inlet portion and water supply connections communicating with said inlet portion.
Claim 8
Dependent Claim
49 words
A headbox in accordance with claim 1, wherein the angle of inclination Alpha of the vanes with reference to the vertical plane is such that tan Alpha > or = d/h, wherein d is the width of a flow channel and h is the height of the flow channel.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-02-11 | 1977-08-13 | 1978-02-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-02-11 | 1981-08-13 | 1982-02-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-02-11 | 1985-08-13 | 1986-02-12 | $7700.00 | Window Closed / Lapsed |