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Expired Canadian patentCanada

Dispersant coated mineral fiber in a drilling fluid

CA 1284577 C · Owner: Mcewen, Terence D. · Inventors: Mcewen, Terence D.; Hansen, John D.

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

An oil well drilling fluid containing mineral fibers which have been coated individually with a dispersant is better able to plug voids and fractures in the rock being drilled than those of the prior art because the mineral fibers are thoroughly dispersed. The fluid is substantially free of modulated fibers. A dispersant such as a polyethoxylated quaternary ammonium salt is added to a stream of air which attenuates streams of molten slag into fibers. The fibers are uniformly coated with the dispersant and nodules thereof unravel easily when placed in a drilling fluid.

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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 June 4, 1991. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended June 4, 2008.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledSeptember 10, 1987
GrantedJune 4, 1991
Term endedJune 4, 2008
Patent numberCA 1284577 C
Classification (IPC)C09K3/00

Timeline

Timeline From CIPO dates

1988199119941997200020032006Application filedSep 10, 1987Patent grantedJune 4, 1991Term endedJune 4, 2008

Sources & verification

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