Patent US2274026A successfully refreshed from Google Patents.
US4436587A
Expired / Lapsed
US
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Method for producing multilayer paper
Assignee: Valmet Technologies Oy
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Filing: 1982-02-23
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Granted: 1984-03-13
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Expires: 2002-02-23
Abstract
Abstract Multilayer paper of superior layer purity and formation is produced by discharging a plurality of superimposed jets of papermaking stock from a headbox into the throat of a roll former, preventing the discharged jets from coming together for a short distance by introducing air between adjacent jets as they leave the headbox, and maintaining the velocity of the jet closest to a plain forming roll in the roll former slightly higher than the velocity of an adjacent discharged jet.
Inventors
- 👤 Ingmar Andersson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 10:46
CPC Classifications
D; D21; D21F; D21F9/00; D21F9/003; D21F9/006
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
160 words
In a method for forming paper by supplying paper stock to a converging throat between two foraminous forming fabrics and dewatering and forming said stock by running said forming fabrics along a curved plain surface of a fabric supporting member with said stock therebetween, the steps of discharging into said throat at least two laterally coextensive, sheet-like jets of paper stock in superimposed, spaced apart relation with a gap therebetween, maintaining in the gap between said jets at the discharge location a wedge-shaped body of gaseous fluid at a pressure such that the adjacent faces of the jets gradually approach one another and meet to form a stratified jet as they travel towards the narrow end of said throat, and setting the discharge velocity of the jet closest to the curved plain surface to be higher than that of an adjacent discharged jet by an amount in the range up to 10% but at least 15 to 20 m/min higher.
Claim 2
Dependent Claim
160 words
In a method for forming paper by supplying paper stock to a converging throat between two foraminous forming fabrics and dewatering and forming said stock by running said forming fabrics along a curved plain surface of a fabric supporting member with said stock therebetween, the steps of discharging into said throat at least two laterally coextensive, sheet-like jets of paper stock in superimposed, spaced apart relation with a gap therebetween, maintaining in the gap between said jets at the discharge location a wedge-shaped body of gaseous fluid at a pressure such that the adjacent faces of the jets gradually approach one another and meet to form a stratified jet as they travel towards the narrow end of said throat, and setting the discharge velocity of the jet closest to the curved plain surface to be higher than that of an adjacent discharged jet by an amount in the range up to 10% but at least 15 to 20 m/min higher.
Claim 3
Dependent Claim
39 words
A paper forming method as defined in claim 1 in which the jets are discharged through headbox slice openings and the relative velocities of the discharged jets are set by adjustment of at least one of said slice openings.
Claim 4
Dependent Claim
53 words
A paper forming method as defined in claim 1 in which the paper stock forming the discharged jets is supplied to headbox slice openings through stacked flow channels in a headbox and the relative velocities of the discharged jets are set by adjustment of the geometry of at least one of said channels.
Claim 5
Dependent Claim
50 words
A paper forming method as defined in claim 1 in which the paper stock forming the discharged jets is supplied to headbox slice openings through stacked flow channels in a headbox and the relative velocities of the discharged jets are set by adjustment of the stock flows through said channels.
Claim 6
Dependent Claim
25 words
A paper making method as defined in claim 1 in which the discharged jets are formed of different stocks so as to produce multilayer paper.
References Cited (Backward Citations)
US4181568A
Cited
US4349414A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-03-13 | 1987-09-12 | 1988-03-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-03-13 | 1991-09-12 | 1992-03-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-03-13 | 1995-09-12 | 1996-03-13 | $7700.00 | Window Closed / Lapsed |