US3948449A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for the treatment of lignocellulosic material
Assignee: Sunds Defibrator Inc
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Filing: 1974-04-29
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Granted: 1976-04-06
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Expires: 1994-04-29
Abstract
Abstract The invention relates to the production of a wholly mechanical pulp of improved strength properties. The lignocellulosic material is fed into a substantially closed chamber where it is mechanically abraded under a power input of fifteen or more horsepower days per ton. During the abrading step, the material is maintained in an inert gaseous atmosphere of a pressure of ten to eighty psig, preferably twenty to forty psig.
Inventors
- 👤 Kenneth C. Logan
- 👤 Friedrich O. B. Luhde
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 09:02
CPC Classifications
D; D21; D21D; D21D1/00; D21D1/20; D21D1/30
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
167 words
Apparatus for producing a pulp having a brightness of at least 50% G.E. and a Canadian Standard Freeness not exceeding 510cc. which includes abrading means for mechanically abrading lignocellulosic fibrous particles, means for feeding a body of wood particles to said abrading means, and means for feeding a substantial quantity of water to said abrading means separate from the moisture naturally present in the wood particles so that it together with moisture in the chips amounts to at least 200 percent of the weight of the dry wood particles and is sufficient to encase the fibers to prevent discoloration due to excessive heating trauma, drive means for operating said abrading means to produce a final product with a total consumption of 30-150 horsepower days per ton of said final product, sealed housing means for subjecting said wood particles during said abrading to an environmental pressure of 10-60 psig and a temperature of 160°F. to 300°F. and means for supplying an inert gaseous atmosphere to said housing means.
Claim 2
Dependent Claim
167 words
Apparatus for producing a pulp having a brightness of at least 50% G.E. and a Canadian Standard Freeness not exceeding 510cc. which includes abrading means for mechanically abrading lignocellulosic fibrous particles, means for feeding a body of wood particles to said abrading means, and means for feeding a substantial quantity of water to said abrading means separate from the moisture naturally present in the wood particles so that it together with moisture in the chips amounts to at least 200 percent of the weight of the dry wood particles and is sufficient to encase the fibers to prevent discoloration due to excessive heating trauma, drive means for operating said abrading means to produce a final product with a total consumption of 30-150 horsepower days per ton of said final product, sealed housing means for subjecting said wood particles during said abrading to an environmental pressure of 10-60 psig and a temperature of 160°F. to 300°F. and means for supplying an inert gaseous atmosphere to said housing means.
Claim 3
Dependent Claim
139 words
Apparatus for producing a paper making pulp comprised of a predominance of long unbroken fibers and having a brightness in excess of 50 G.E. and a Canadian Standard Freeness not exceeding 510cc. comprising abrading means, housing means surrounding said abrading means for maintaining said abrading means in a pressurized environment, supply means for feeding lignocellulosic fibrous particles to said abrading means and means for supplying a substantial quantity of liquid water to said abrading means while maintaining a pressurized environment in said housing, discharge means for removing the fibrous end product from said housing means while maintaining a pressurized environment inside of the housing means, drive means for operating said abrading means with a minimum total power consumption of 30 horsepower days per ton of fibrous end product and means for supplying a pressure medium to said housing means.
Claim 4
Dependent Claim
139 words
Apparatus for producing a paper making pulp comprised of a predominance of long unbroken fibers and having a brightness in excess of 50 G.E. and a Canadian Standard Freeness not exceeding 510cc. comprising abrading means, housing means surrounding said abrading means for maintaining said abrading means in a pressurized environment, supply means for feeding lignocellulosic fibrous particles to said abrading means and means for supplying a substantial quantity of liquid water to said abrading means while maintaining a pressurized environment in said housing, discharge means for removing the fibrous end product from said housing means while maintaining a pressurized environment inside of the housing means, drive means for operating said abrading means with a minimum total power consumption of 30 horsepower days per ton of fibrous end product and means for supplying a pressure medium to said housing means.
Claim 5
Dependent Claim
22 words
Apparatus as set forth in claim 2 further comprising means for preheating said fibrous particles prior to introduction into said abrading means.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-04-06 | 1979-10-06 | 1980-04-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-04-06 | 1983-10-06 | 1984-04-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-04-06 | 1987-10-06 | 1988-04-06 | $7700.00 | Window Closed / Lapsed |