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Expired Canadian patentCanada

Mixing oxygen gas with medium consistency pulp in a pump discharge

CA 1269502 C · Owner: Kamyr, Inc. · Inventors: Wiley, William Eric

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Abstract From the Canadian patent

Oxygen delignification of paper pulp (comminuted cellulosic material in a slurry) at medium consistency (i.e. about 6-18%) is practiced without the necessity of a separate mixer. The pulp is drawn into the inlet of a fluidizing centrifugal pump capable of pumping medium consistency pulp. The pump typically has a vacuum system associated with it for effecting degassing of the pulp. As the pulp is pumped out of the pump outlet, oxygen gas is added to the pulp. This is accomplished utilizing a shear plate having a central opening and one or more radial bores, oxygen being introduced under pressure into the bores to pass into the pulp flowing through the plate central opening. A tube may be …

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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 May 29, 1990. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended May 29, 2007.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledDecember 2, 1985
GrantedMay 29, 1990
Term endedMay 29, 2007
Patent numberCA 1269502 C
Classification (IPC)D21G9/00 +2 more

Timeline

Timeline From CIPO dates

19861989199219951998200120042007Application filedDec 2, 1985Patent grantedMay 29, 1990Term endedMay 29, 2007

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