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Expired Canadian patentCanada

Gas-insulated electric apparatus and method of assembly thereof

CA 1231146 A · Owner: Hitachi, Ltd. · Inventors: Yamagiwa, Tokio; Kamata, Yuzuru; Endo, Fumihiro

CIPO record

Overview

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

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Abstract From the Canadian patent

An electorate capable of holding electric charges semi-permanently is used to attract conductive particles generated or intruded in a gas-insulated electric apparatus during assembly work including an operation test of movable parts thereof, thus improving the reliability of insulation characteristic of the apparatus.

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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 January 5, 1988. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended January 5, 2005.
  • 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 17, 1985
GrantedJanuary 5, 1988
Term endedJanuary 5, 2005
Patent numberCA 1231146 A
Classification (IPC)H02G5/06

Timeline

Timeline From CIPO dates

1986198819901992199419961998200020022004Application filedApril 17, 1985Patent grantedJan 5, 1988Term endedJan 5, 2005

Sources & verification

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