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Expired Canadian patentCanada

Fluid-cooled hollow copper electrodes and their use in corona or ozone applications

CA 2121944 C · Owner: Praxair S.T. Technology, Inc. · Inventors: Ford, Keith Graham; Stephenson, Peter Kevin; Hatch, Russell Bruce

CIPO record

Overview

Drawings and full text

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

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Abstract From the Canadian patent

A hollow elongated copper corona electrode that contains a dielectric coating and is cooled by a fluid such as a water-base liquid, being fed through the electrode and a process for using such an electrode in a corona apparatus or in an ozone generator.

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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 April 22, 1994 and granted June 22, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended April 22, 2014.
  • A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by April 22, 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.
FiledApril 22, 1994
GrantedJune 22, 1999
Term endedApril 22, 2014
Patent numberCA 2121944 C
Classification (IPC)H01T19/00 +1 more

Timeline

Timeline From CIPO dates

1995199719992001200320052007200920112013Application filedApril 22, 1994Patent grantedJune 22, 1999Term endedApril 22, 2014

Sources & verification

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