US3873412A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Mechanically refining a mixture of kraft and semichemical pulp
Assignee: Sprout Bauer Inc
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Filing: 1974-04-01
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Granted: 1975-03-25
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Expires: 1994-04-01
Abstract
Abstract Method for producing pulp for use in the manufacture of kraft type products such as linerboard and bag grade paper comprising the steps of steaming small segments of fibrous material, defiberizing the same in a pressurized atmosphere and at an elevated temperature and, while the resultant fiber products are still hot, mixing them with a hot kraft pulp and then refining the mixture so obtained.
Inventors
- 👤 Michael T Charters
- 👤 Franklin E Landis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 17:48
CPC Classifications
D; D21; D21B; D21B1/00; D21B1/04; D21B1/12
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
64 words
A PROCESS OF PRODUCING A PULP SUITED FOR USE IN THE MANUFACTURE OF KRAFT TYPE PRODUCTS, FOR EXAMPLE LINERBOARD AND BAG GRADE PAPER, COMPRISING THE STEPS OF STEAMING SMALL SEGMENTS OF FIBEROUS MATERIAL, DEFIBERIZING THE SAME AND ELEVATING THE TEMPERATURE THEREOF AND WHILE THE DEFIBERIZED MATERIALS ARE STILL AT ELEVATED TEMPERATURE MIXING THEM WITH A HOT KRAFT AND MECHANICALLY REFINING THE MIXTURE SO OBTAINED.
Claim 2
Dependent Claim
64 words
A PROCESS OF PRODUCING A PULP SUITED FOR USE IN THE MANUFACTURE OF KRAFT TYPE PRODUCTS, FOR EXAMPLE LINERBOARD AND BAG GRADE PAPER, COMPRISING THE STEPS OF STEAMING SMALL SEGMENTS OF FIBEROUS MATERIAL, DEFIBERIZING THE SAME AND ELEVATING THE TEMPERATURE THEREOF AND WHILE THE DEFIBERIZED MATERIALS ARE STILL AT ELEVATED TEMPERATURE MIXING THEM WITH A HOT KRAFT AND MECHANICALLY REFINING THE MIXTURE SO OBTAINED.
Claim 3
Dependent Claim
46 words
A process of producing pulp as in claim 1 characterized by elevating the temperature of said defiberized material by subjecting the same to a hot black liquor having a temperature in the range of 140*F. to 250*F. prior to mixing thereof with said hot kraft stock.
Claim 4
Dependent Claim
24 words
A process of producing pulp as in claim 2 characterized by applying said hot black liquor at a temperature in the neighborhood of 212*F.
Claim 5
Dependent Claim
26 words
A process of producing pulp as in claim 2 wherein the step of defiberizing said segments is carried out by a disc refining said steamed segments.
Claim 6
Dependent Claim
21 words
A process of producing pulp as in claim 4 wherein said disc refining step is carried out in a pressurized environment.
Claim 7
Dependent Claim
97 words
A process of producing pulp as in claim 1 wherein, immediately following the defiberizing of said steamed segments, the said defiberized material is introduced to a vessel with hot black liquor and in said vessel subjected with said liquor to a centrifugal separation action, in the course of which the fibers of said defiberized material are subjected to the chemical content of said liquor and caused to achieve and maintain an elevated temperature and then discharge and in a continuing movement thereof combine with the hot kraft stock to produce said mixture which is then further refined.
Claim 8
Dependent Claim
97 words
A process of producing pulp as in claim 6 wherein the said segments of fibrous material, following defiberizing thereof, are discharged to a blow tank which commonly receives said hot kraft stock and the mixture so produced is subjected to an application of hot black liquor at a temperature in the range of 140*F. to 250*F. to maintain the temperature of said defiberized material and react thereon in the course of flow therewith to refiner means wherein the mixture so obtained is subjected to a further refining procedure and the resultant stock forwarded for screening and washing.
Claim 9
Dependent Claim
51 words
A process of producing pulp as in claim 6 wherein following the centrifugal separating action said definerized material at an elevated temperature is introduced to a vessel wherein the hot kraft stock is also introduced and mixed therewith in the presence of hot black liquor prior to refining the resultant mixture.
Claim 10
Dependent Claim
103 words
A process of producing pulp as in claim 6 wherein following the centrifugal separating action said defiberized material at elevated temperature is introduced to a vessel wherein additional hot black liquor is added to maintain it at an elevated temperature and have the chemical content react thereon and then the resultant mixture is flowed to a further refiner means and in the course of its flow the hot kraft stock is introduced thereto to merge and mix therewith in movement to said further refiner means wherein the resulting mixture is subjected to refining as a composite to result in an intermingled pulp product.
Claim 11
Dependent Claim
40 words
A process of producing pulp according to claim 1 wherein prior to being steamed said segments are pressed and subjected upon release from the pressing action to an application of chemicals such as NaOH, Na2S, NaOH+ Na2S or Na2Sx (polysulfide).
Claim 12
Dependent Claim
48 words
A process for producing pulp as in claim 1 wherein said segments are steamed for a period up to ten minutes at pressures of 10 to 150 p.s.i.g. and at consistencies from 15 to 40 percent before defiberizing and the defiberizing is effected under conditions of elevated pressure.
Claim 13
Dependent Claim
30 words
A process of producing pulp as in claim 11 characterized by mixing the defiberized segments with hot kraft pulp in hot black liquor at a temperature of 140*F. to 250*F.
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) | 1978-03-24 | 1978-09-23 | 1979-03-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-24 | 1982-09-23 | 1983-03-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-24 | 1986-09-23 | 1987-03-25 | $7700.00 | Window Closed / Lapsed |