Patent US2255079A successfully refreshed from Google Patents.
US4909899A
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Method of concentrating sludges
Assignee: Ahlstrom Corp
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Filing: 1987-09-21
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Granted: 1990-03-20
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Expires: 2007-09-21
Abstract
Abstract A method of concentrating sludges wherein liquor is heated under pressure indirectly with flue gases from the combustion of previously concentrated sludge, after which the sludge is caused to expand or subjected to reduced pressure which results in evaporation of water and concentration of the sludge to a dry-substance content of over 55%.
Inventors
- 👤 Erkki J. Kiiskila
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 21:26
CPC Classifications
B; B01; B01D; B01D3/00; B01D3/06; C; C02; C02F; C02F1/00; C02F1/02; C02F1/04; C02F1/048; C02F11/00; C02F11/12; C02F11/13; Y; Y10; Y10S; Y10S159/00; Y10S159/32; Y10S203/00; Y10S203/08
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
68 words
A method of concentrating waste liquors from pulp production to a dry-substance content of greater than 55%, consisting essentially of indirectly heating the waste liquor under pressure with flue gases produced by combustion of previously concentrated waste liquor, and evaporating water from the thus heated waste liquor by expansion thereof at a lower pressure to concentrate the waste liquor to a dry-substance content which is greater than 55%.
Claim 2
Independent Claim
68 words
A method of concentrating waste liquors from pulp production to a dry-substance content of greater than 55%, consisting essentially of indirectly heating the waste liquor under pressure with flue gases produced by combustion of previously concentrated waste liquor, and evaporating water from the thus heated waste liquor by expansion thereof at a lower pressure to concentrate the waste liquor to a dry-substance content which is greater than 55%.
Claim 3
Dependent Claim
23 words
A method as claimed in claim 1, wherein the expansion produces steam which is used as primary steam in a series evaporation plant.
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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) | 1993-03-19 | 1993-09-18 | 1994-03-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-03-19 | 1997-09-18 | 1998-03-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-03-19 | 2001-09-18 | 2002-03-20 | $7700.00 | Window Closed / Lapsed |