US4247363A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for producing stone groundwood pulp from wood chips by using a stone grinder
Assignee: New Oji Paper Co Ltd
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Filing: 1978-10-04
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Granted: 1981-01-27
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Expires: 1998-10-04
Abstract
Abstract Disclosed is a process for producing stone groundwood pump from wood chips, by compressing a wood chip mass into an apparent volume corresponding to 70% or less, preferably, from 40 to 60%, of the original apparent volume of the wood chip mass and by grinding the compressed wood chip mass, under pressure, with a stone grinder. The wood chips may be treated, before the grinding step, with both or either one of steam and a treating agent, such as sodium monosulfite, sodium disulfite and sodium bicarbonate.
Inventors
- 👤 Shigeharu Soma
- 👤 Tadao Onodera
- 👤 Yoshio Onodera
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 01:50
CPC Classifications
D; D21; D21B; D21B1/00; D21B1/04; D21B1/12; D21B1/14; D21B1/18; D21B1/24
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
212 words
A process for producing stone groundwood pulp from wood chips by using a stone grinder of the type having at least one pocket for containing wood chips, which process comprises the steps of: placing a mass of wood chips into said at least one pocket; compressing said mass of wood chips within said at least one pocket under a pressure of from 1.5 to 10 kg/cm 2 until the apparent volume of the compressed wood chip mass reaches a value corresponding to 70% or less of the original apparent volume of the wood chip mass, and the fibers of the wood chips become substantially parallel to the bottom surface of the compressed mass, and; grinding said compressed wood chip mass by bringing a bottom surface of said compressed wood chip mass into contact with a peripheral grinding surface of a grinding stone of a stone grinder, wherein the fibers of the compressed wood chip mass is substantially parallel to either the shaft of the grinding stone around which the stone rotates, or a line targent to the peripheral grinding surface of the grinding stone, and by maintaining the pressure applied to said compressed wood chip mass at a level of from 1.5 to 5 kg/cm 2 , while rotating said grinding stone.
Claim 2
Dependent Claim
212 words
A process for producing stone groundwood pulp from wood chips by using a stone grinder of the type having at least one pocket for containing wood chips, which process comprises the steps of: placing a mass of wood chips into said at least one pocket; compressing said mass of wood chips within said at least one pocket under a pressure of from 1.5 to 10 kg/cm 2 until the apparent volume of the compressed wood chip mass reaches a value corresponding to 70% or less of the original apparent volume of the wood chip mass, and the fibers of the wood chips become substantially parallel to the bottom surface of the compressed mass, and; grinding said compressed wood chip mass by bringing a bottom surface of said compressed wood chip mass into contact with a peripheral grinding surface of a grinding stone of a stone grinder, wherein the fibers of the compressed wood chip mass is substantially parallel to either the shaft of the grinding stone around which the stone rotates, or a line targent to the peripheral grinding surface of the grinding stone, and by maintaining the pressure applied to said compressed wood chip mass at a level of from 1.5 to 5 kg/cm 2 , while rotating said grinding stone.
Claim 3
Dependent Claim
19 words
A process as claimed in claim 1, wherein said wood chips are treated with steam, before the grinding operation.
Claim 4
Dependent Claim
19 words
A process as claimed in claim 2, wherein said steam has a temperature of from 100° to 130° C.
Claim 5
Dependent Claim
33 words
A process as claimed in claim 1, wherein the compressed wood chip mass has an apparent volume corresponding to from 40 to 60% of the original apparent volume of the wood chip mass.
Claim 6
Dependent Claim
20 words
A process as in claim 1 wherein said wood chips are treated with a treating agent before the grinding operation.
Claim 7
Dependent Claim
22 words
A process as in claim 1 wherein said wood chips are treated with steam and a treating agent before the grinding operation.
Claim 8
Dependent Claim
36 words
A process as claimed in claims 5 or 6 wherein said treating agent is selected from the group consisting of sodium bisulfite, sodium monosulfite, sodium bicarbonate and mixtures of two or more of the above-mentioned compounds.
Claim 9
Dependent Claim
32 words
A process as claimed in claims 5 or 6 wherein said treating agent is absorbed in an amount of from 0.5 to 20% based on the dry weight of the wood chips.
References Cited (Backward Citations)
US1399976A
Cited
US1532946A
Cited
US2075023A
Cited
US2689092A
Cited
US3612413A
Cited
US3690568A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-01-27 | 1984-07-28 | 1985-01-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-01-27 | 1988-07-28 | 1989-01-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-01-27 | 1992-07-28 | 1993-01-27 | $7700.00 | Window Closed / Lapsed |