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Expired Canadian patentCanada

Non-stressed, high strength, cement-containing pipe and its production

CA 1082621 A · Owner: Cement Asbestos Products Company · Inventors: Wright, James

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

Non-stressed high strength, substantially inflex-, ible rigid, cement-containing pipe, for example asbestos-, cement pipe well adapted as high pressure water pipe com-, prising a tubular article body of spirally wound up layers of asbestos-cement, and a plurality of helical windings of a continuous filament of an aromatic polyamide fiber known and obtainable as KEVLAR aramid fiber about one or more of the asbestos-cement layers within the interior of the pipe without being stretched and without being in tension. The aromatic polyamide fiber of the continuous filament is of high tensile strength of about 390,000 psi or higher and a low elongation capability of no more than 7%, and the …

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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 July 29, 1980. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended July 29, 1997.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledNovember 28, 1977
GrantedJuly 29, 1980
Term endedJuly 29, 1997
Patent numberCA 1082621 A
Classification (IPC)B65H81/00

Timeline

Timeline From CIPO dates

1978198019821984198619881990199219941996Application filedNov 28, 1977Patent grantedJuly 29, 1980Term endedJuly 29, 1997

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