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Expired Canadian patentCanada

Process for removing anthraquinone type scale

CA 1182723 A · Owner: Kawasaki Kasei Chemicals Ltd. · Inventors: Sakai, Kazuaki; Sato, Tuneyasu; Chiba, Kazuhiko

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Abstract From the Canadian patent

A process for removing an anthraquinone type scale comprises condensing steam evaporated from a black liquor obtained by separating pulp from a digested mixture of lignocelluloses containing an anthraquinone type digesting assistant; and contacting a heated aqueous solution of a base in the presence or absence of a reducing agent or an alkali resistant surfactant with a wall of a condenser of an evaporator on which said anthraquinone type scale is adhered.

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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

  • Granted February 19, 1985. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended February 19, 2002.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledNovember 27, 1981
GrantedFebruary 19, 1985
Term endedFebruary 19, 2002
Patent numberCA 1182723 A
Classification (IPC)B08B3/08 +2 more

Timeline

Timeline From CIPO dates

1982198519881991199419972000Application filedNov 27, 1981Patent grantedFeb 19, 1985Term endedFeb 19, 2002

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Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.