US3907630A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of fiber board article production employing predrying of the ligno-cellulosic material prior to liquid suspension and article formation, and employing water recirculation
Assignee: Valmet AB
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Filing: 1973-11-21
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Granted: 1975-09-23
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Expires: 1993-11-21
Abstract
Abstract Fiber board articles are formed by first defibering the lignocellulosic material, then pre-drying the defibered material with a gaseous heating medium, forming a suspension of the defibered and dried material in water, forming blanks of fiber board by draining liquid from the suspension through a forming wire, pressing the board produce to a dryness of up to 65% and subjecting the board in blank form to final drying under heat and mechanical pressure. The pre-drying of the defibered material prior to suspension in liquid is conducted so as to bring the material to a dryness level which is equal to or higher than the dryness level of the board product subsequent to formation and pressing, such that only water in steam phase is released during the final drying step. Substantially all the water which is separated from the board during the formation and pressing steps is recirculated to suspension step.
Inventors
- 👤 Stig Selander
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 20:41
CPC Classifications
D; D21; D21J; D21J1/00
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
175 words
IN THE METHOD OF PRODUCING FORMED BODIES OF LIGNOCELLULOSE-CONTAINING MATERIAL COMPRISING THE STEPS OF (A) DEFIBERING THE MATERIAL IN AT LEAST ONE STAGE, (B) FORMING THE DEFIBERED MATERIAL INTO A SUSPENSION THEREOF IN WATER, SAID WATER SERVING AS PROPELLANT LIQUID FOR THE DEFIBERED MATERIAL, (C) FORMING BLANKS FOR SHAPED ARTICLES FROM SAID SUSPENSION BY MECHANICALLY SEPARATING AND PRESSING WATER IN LIQUID PHASE FROM SAID SUSPENSION, AND (D) THEREAFTER SUBJECTING THE BLANKS TO FINAL DRYING UNDER HEAT AND MECHANICAL PRESSURE, THE IMPROVEMENT WHICH COMPRISES SUBJECTING THE DEFIBERED MATERIAL, PRIOR TO SAID SUSPENSION-FORMING STEP (B) TO A PRE-DRYING ACTION WITH A GASEOUS HEATING MEDIUM TO A CONDITON IN WHICH ITS DRY CONTENT IS BROUGHT TO A LEVEL WHICH IS AT LEAST EQUAL TO OR HIGHER THAN THE DRY CONTENT OF SAID BLANKS AFTER MECHANICAL SEPARATION OF WATER IN SAID FORMING STEP (C) SO THAT WATER IS REMOVED SUBSTANTIALLY ONLY IN STEAM PHASE DURING SAID DRYING STEP (D) WHILE SUBSTANTIALLY ALL WATER SEPARATED FROM SAID SUSPENSION IN SAID FORMING STEP (C) IS RECIRCULATED TO THE SUSPENSION-FORMING STEP (B).
Claim 2
Dependent Claim
175 words
IN THE METHOD OF PRODUCING FORMED BODIES OF LIGNOCELLULOSE-CONTAINING MATERIAL COMPRISING THE STEPS OF (A) DEFIBERING THE MATERIAL IN AT LEAST ONE STAGE, (B) FORMING THE DEFIBERED MATERIAL INTO A SUSPENSION THEREOF IN WATER, SAID WATER SERVING AS PROPELLANT LIQUID FOR THE DEFIBERED MATERIAL, (C) FORMING BLANKS FOR SHAPED ARTICLES FROM SAID SUSPENSION BY MECHANICALLY SEPARATING AND PRESSING WATER IN LIQUID PHASE FROM SAID SUSPENSION, AND (D) THEREAFTER SUBJECTING THE BLANKS TO FINAL DRYING UNDER HEAT AND MECHANICAL PRESSURE, THE IMPROVEMENT WHICH COMPRISES SUBJECTING THE DEFIBERED MATERIAL, PRIOR TO SAID SUSPENSION-FORMING STEP (B) TO A PRE-DRYING ACTION WITH A GASEOUS HEATING MEDIUM TO A CONDITON IN WHICH ITS DRY CONTENT IS BROUGHT TO A LEVEL WHICH IS AT LEAST EQUAL TO OR HIGHER THAN THE DRY CONTENT OF SAID BLANKS AFTER MECHANICAL SEPARATION OF WATER IN SAID FORMING STEP (C) SO THAT WATER IS REMOVED SUBSTANTIALLY ONLY IN STEAM PHASE DURING SAID DRYING STEP (D) WHILE SUBSTANTIALLY ALL WATER SEPARATED FROM SAID SUSPENSION IN SAID FORMING STEP (C) IS RECIRCULATED TO THE SUSPENSION-FORMING STEP (B).
Claim 3
Dependent Claim
18 words
The improvement according to claim 1, wherein fresh water is added to said blanks formed in step (c).
Claim 4
Dependent Claim
39 words
The improvement according to claim 2, wherein said fresh water is added in such a manner that lignocellulose-containing substances dissolved in the top layer of said blanks will be displaced from the surfaces toward the interior of the blanks.
Claim 5
Dependent Claim
32 words
The improvement according to claim 2, wherein chemicals which affect the qualitative characteristics of the final formed bodies of lignocellulose-containing material are added to the formed blanks together with the fresh water.
References Cited (Backward Citations)
US2675745A
Cited
US2016657A
Cited
US2156445A
Cited
US2373914A
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US2633062A
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US2924548A
Cited
US3056718A
Cited
US3446697A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-09-22 | 1979-03-24 | 1979-09-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-22 | 1983-03-24 | 1983-09-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-22 | 1987-03-24 | 1987-09-23 | $7700.00 | Window Closed / Lapsed |