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Expired Canadian patentCanada

Differential vent and bar actuated circulating valve and method

CA 1211043 A · Owner: Halliburton Company · Inventors: Brieger, Emmet F.

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

A tool for use downhole in a borehole for carrying out a backsurging method whereby existing open perforations are cleaned. The tool comprises an annular body having spaced cylindrical walls, each of which reciprocatingly receives spaced pistons which move individually relative to one another. A port is formed through each of the walls of each of the cylinders with the first port being normally closed by a first piston and the second port being normally open. The second piston is moved to close the second port. The tool is placed on the end of a tubing string or within a tool string and run downhole into the borehole. A packer device enables the pressure between the lower annulus, the upper …

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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 September 9, 1986. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended September 9, 2003.
  • 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 18, 1983
GrantedSeptember 9, 1986
Term endedSeptember 9, 2003
Patent numberCA 1211043 A
Classification (IPC)E21B34/12 +2 more

Timeline

Timeline From CIPO dates

1984198619881990199219941996199820002002Application filedAug 18, 1983Patent grantedSep 9, 1986Term endedSep 9, 2003

Sources & verification

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