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Expired Canadian patentCanada

Two-section arctic drilling structure

CA 1185104 A · Owner: Shell Canada Limited · Inventors: Tiedemann, James B.

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 lightweight drilling structure for use in offshore arctic waters comprising a lower frustoconical section and upper section wherein the lower section is towed to location ballasted to sink in place on the sea floor and anchored in position by flooding the stability compartments. The upper section containing the drilling rig and equipment is then floated into place over the lower section ballasted to rest, on the lower section and the two sections sealed and fastened together. The assembled structure is firmly anchored in place by dewatering chambers located in the bottom of the lower section to create a suction between the bottom of the lower section and the ocean floor.

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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 April 9, 1985. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended April 9, 2002.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledJanuary 11, 1983
GrantedApril 9, 1985
Term endedApril 9, 2002
Patent numberCA 1185104 A
Classification (IPC)E02B17/00

Timeline

Timeline From CIPO dates

1984198619881990199219941996199820002002Application filedJan 11, 1983Patent grantedApril 9, 1985Term endedApril 9, 2002

Sources & verification

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