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Expired Canadian patentCanada

Method for reclassifying pcb transformers

CA 2017472 C · Owner: Shisler, Roger Allen · Inventors: Mcdermott, John Brian; Smith, Daniel Preston; Horneck, Craig William

CIPO record

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Its claims, description and drawings are in the Canadian Patents Database.

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Abstract From the Canadian patent

The present invention is directed to a method for reducing PCB concentration in an electrical induction apparatus containing a dielectric fluid with greater than 500 ppm PCB to a level of less than about 50 ppm PCB. Dielectric fluid containing greater than 500 ppm PCB is drained from an electrical induction apparatus and the, drained apparatus then is filled with tetrachloroethylene as a first interim dielectric fluid. The apparatus is then electrically operated with the first interim dielectric fluid so as to attain about an equilibrium PCB concentration in the first fluid. The first interim dielectric fluid then is drained from the apparatus and replaced with fresh tetrachloroethylene as …

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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 May 24, 1990 and granted May 26, 1998. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended May 24, 2010.
  • A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by May 24, 2012.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledMay 24, 1990
GrantedMay 26, 1998
Term endedMay 24, 2010
Patent numberCA 2017472 C
Classification (IPC)H01F41/00 +1 more

Timeline

Timeline From CIPO dates

1991199319951997199920012003200520072009Application filedMay 24, 1990Patent grantedMay 26, 1998Term endedMay 24, 2010

Sources & verification

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