US3966542A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Multi-stage bleaching of pulp using successively lower power levels
Assignee: SPX Technologies Inc
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Filing: 1974-09-20
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Granted: 1976-06-29
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Expires: 1994-09-20
Abstract
Abstract A process for bleaching pulp in tank comprises several steps. A pulp slurry and an oxidizing agent are supplied to a first tank compartment. The mixture of pulp slurry and oxidizing agent is agitated at a first power level that corresponds to an approximate minimum power level for a maximum reaction rate on a plot of reaction rate versus power level for a first residence time. The mixture is re-agitated in another tank compartment at a second power level that corresponds to an approximate minimum power level for a maximum reaction rate on a plot of reaction rate versus power level for a second residence time. The second power level is lower than said first power level and corresponds to the amount of unreacted oxidizing agent and unreacted pulp slurry.
Inventors
- 👤 James Y. Oldshue
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 22:24
CPC Classifications
D; D21; D21C; D21C9/00; D21C9/10; D21C9/1026; D21C9/1052
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
97 words
A process for bleaching pulp in a tank comprising the steps of: a. supplying a pulp slurry to a first tank compartment; b. supplying an oxidizing agent to said first tank compartment; c. agitating a mixture of said pulp slurry and oxidizing agent in said first tank compartment at a first power level; d. supplying said mixture to another tank compartment; and e. re-agitating said mixture in said another tank compartment at a second power level that is lower than said first power level and corresponds to the amount of unreacted oxidizing agent and unreacted pulp slurry.
Claim 2
Dependent Claim
97 words
A process for bleaching pulp in a tank comprising the steps of: a. supplying a pulp slurry to a first tank compartment; b. supplying an oxidizing agent to said first tank compartment; c. agitating a mixture of said pulp slurry and oxidizing agent in said first tank compartment at a first power level; d. supplying said mixture to another tank compartment; and e. re-agitating said mixture in said another tank compartment at a second power level that is lower than said first power level and corresponds to the amount of unreacted oxidizing agent and unreacted pulp slurry.
Claim 3
Dependent Claim
24 words
The process defined in claim 1, wherein said second power level is reduced by decreasing the horsepower of a mixer which re-agitates said mixture.
Claim 4
Dependent Claim
19 words
The process defined in claim 2, wherein said re-agitating includes re-agitating said mixture in at least two tank compartments.
Claim 5
Dependent Claim
22 words
The process defined in claim 1, wherein said second power level is reduced by increasing the volume of said another tank compartment.
Claim 6
Dependent Claim
19 words
The process defined in claim 4, wherein said re-agitating includes re-agitating said mixture in at least two tank compartments.
Claim 7
Dependent Claim
33 words
The process defined in claim 1, wherein said second power level is reduced by decreasing the horsepower of a mixer which re-agitates said mixture and increasing the volume of said another tank compartment.
Claim 8
Dependent Claim
19 words
The process defined in claim 6, wherein said re-agitating includes re-agitating said mixture in at least two tank compartments.
Claim 9
Dependent Claim
30 words
The process defined in claim 7, wherein said re-agitating further includes re-agitating said mixture at successively lower power levels as said mixture passes through said at least two tank compartments.
Claim 10
Dependent Claim
12 words
The process defined in claim 1, wherein said oxidizing agent is chlorine.
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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) | 1979-06-29 | 1979-12-29 | 1980-06-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-06-29 | 1983-12-29 | 1984-06-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-06-29 | 1987-12-29 | 1988-06-29 | $7700.00 | Window Closed / Lapsed |