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Expired Canadian patentCanada

Electrical power cable underground-laying depth measuring method

CA 2213641 C · Owner: Yamaguchi, Masayoshi · Inventors: Hata, Ryosuke; Yamaguchi, Masayoshi; Nakura, Yuji

CIPO record

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Abstract From the Canadian patent

The underground-laying depth of an electric power cable is obtained on the basis of temperature data of the electric power cable laid underground, ambient temperature data of a place where the electric power cable is laid underground, calorific power data of the electric power cable, thermal resistivity of soil where the electric power cable is laid underground, and radiation thermal resistivity of the surface of the electric power cable. The ambient temperature means the temperature of a place which is not influenced by the heat of the electric power cable.

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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 August 22, 1997 and granted May 20, 2003. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended August 22, 2017.
  • A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by August 22, 2019.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledAugust 22, 1997
GrantedMay 20, 2003
Term endedAugust 22, 2017
Patent numberCA 2213641 C
Classification (IPC)G01V9/00 +2 more

Timeline

Timeline From CIPO dates

1998200020022004200620082010201220142016Application filedAug 22, 1997Patent grantedMay 20, 2003Term endedAug 22, 2017

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