Dissolved solids control in pulp production
CA 2424682 A1 · Owner: Laakso, Richard O. · Inventors: Chasse, R. Fred; Ryham, Rolf C.; Prough, J. Robert
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Kraft pulp of increased strength and bleachability may be produced with deceased consumption of effective alkali and at a lower H factor, by, keeping the dissolved organic material (DOM) concentration low substantially through the entire kraft cook including by extracting high, DOM liquid from at least one part of a continuous digester and replacing it with much lower level DOM liquid. Existing pulp mills having twovessel hydraulic, one-vessel hydraulic or other systems may be retrofit to, provide for extractions and additions of low DOM dilution liquor (including substantially DOM-free white liquor). Also commercial size, batch digesters (8 tons per day of pulp or more) can be operated …
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Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Filed February 25, 1994. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended February 25, 2014.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by February 25, 2016.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.