US4000032A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process of freeing cellulose fibers from lignocellulosic material by irradiation
Assignee: Mo och Domsjo AB
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Filing: 1975-09-23
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Granted: 1976-12-28
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Expires: 1995-09-23
Abstract
Abstract A process is provided for freeing cellulose fibers from lignocellulosic material, which comprises subjecting particulate lignocellulosic material to irradiation at a frequency within the range from about 10 to about 300,000 MHz (megahertz), at an intensity of at least 0.5 megajoule per kg. of material, applied in a short pulse having a duration of at most 0.1 second, at such an intensity the water present in the lignocellulosic material is rapidly and even explosively vaporized, and disrupts or destroys the natural structure of the lignocellulosic material, thereby freeing the fibers substantially without deleterious effect upon the length or strength of the fibers.
Inventors
- 👤 John Rickard Bergstrom
- 👤 Ernst Birger Tiberg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 21:14
CPC Classifications
D; D21; D21B; D21B1/00; D21B1/04; D21B1/12; D21B1/30; D21B1/32; D21B1/325; Y; Y02; Y02W; Y02W30/00; Y02W30/50; Y02W30/64
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
96 words
A process for freeing cellulose fibers of particulate lignocellulosic material which comprises supplying the energy required to vaporize water contained in lignocellulosic material by subjecting particulate lignocellulosic material having a water content of at least 10% by weight to irradiation at a frequency within the range from about 10 to about 300,000 MHz, at an intensity of at least 0.5 megajoule per kg of material, applied in a short pulse having a duration of at most 0.1 second, sufficient to vaporize the water and disintegrate the lignocellulosic structure to an extent to free the cellulose fibers.
Claim 2
Dependent Claim
96 words
A process for freeing cellulose fibers of particulate lignocellulosic material which comprises supplying the energy required to vaporize water contained in lignocellulosic material by subjecting particulate lignocellulosic material having a water content of at least 10% by weight to irradiation at a frequency within the range from about 10 to about 300,000 MHz, at an intensity of at least 0.5 megajoule per kg of material, applied in a short pulse having a duration of at most 0.1 second, sufficient to vaporize the water and disintegrate the lignocellulosic structure to an extent to free the cellulose fibers.
Claim 3
Dependent Claim
23 words
A process according to claim 1, which comprises heating the lignocellulosic material to a temperature of at least 70° C prior to irradiation.
Claim 4
Dependent Claim
13 words
A process according to claim 1, in which the lignocellulosic material is wood.
Claim 5
Dependent Claim
46 words
A process according to claim 3, in which the wood is in the form of chips having a size within the range from about 5 to 30 mm by from about 10 to 40 mm, with a thickness of from about 0.5 to about 10 mm.
Claim 6
Dependent Claim
26 words
A process according to claim 1, in which the lignocellulosic material has a water content within the range from about 10 to about 99% by weight.
Claim 7
Dependent Claim
26 words
A process according to claim 5, in which the lignocellulosic material has a water content within the range from about 50 to about 90% by weight.
Claim 8
Dependent Claim
23 words
A process according to claim 1, in which the radiation has a frequency within the range from about 200 to about 50,000 MHz.
Claim 9
Dependent Claim
23 words
A process according to claim 7, in which the radiation has a frequency within the range from about 800 to about 15,000 MHz.
Claim 10
Dependent Claim
25 words
A process according to claim 1, which comprises applying the radiation while the lignocellulosic material is under a superatmospheric gas pressure which is then released.
Claim 11
Dependent Claim
21 words
A process according to claim 1, which comprises applying the radiation while the lignocellulosic material is under a subatmospheric gas pressure.
Claim 12
Dependent Claim
22 words
A process according to claim 1, in which the lignocellulosic material has been partially mechanically defibrated, prior to application of the radiation.
Claim 13
Dependent Claim
22 words
A process according to claim 1, in which the lignocellulosic material has been partially pulped chemically, prior to application of the radiation.
References Cited (Backward Citations)
CA454127A
Cited
US3092536A
Cited
GB1162055A
Cited
US3535795A
Cited
US3682643A
Cited
US3759783A
Cited
US3678594A
Cited
US3801432A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-12-28 | 1980-06-28 | 1980-12-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-12-28 | 1984-06-28 | 1984-12-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-12-28 | 1988-06-28 | 1988-12-28 | $7700.00 | Window Closed / Lapsed |