Acidity control in chlorine dioxide manufacture
CA 2116427 C · Owner: Noreus, Sture E. O. · Inventors: Noreus, Sture E. O.; Brannland, Rolf C.A.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The continuous generation of chlorine dioxide by reduction of sodium chlorate with sulphur dioxide sodium, chloride, methanol or some other suitable reluctant requires acid reaction conditions. According to the invention the acidity is maintained, completely or partially with, acid produced by the electrolysis of a solution of sodium sulphate (Na2SO4 or Na3HSO42). This sulphate is obtained by crystallization and redissolution of sodium sulphate formed in the chlorine dioxide generating process. The electrolysis of the sodium sulphate is limited for reasons of efficiency, such that only a part of the sulphate is decomposed to acid, whereas the remainder is recycled together with the acid to …
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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 September 12, 1991 and granted September 29, 1998. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended September 12, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by September 12, 2013.
- 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.