Rotatable reciprocating collar for borehole casing and stage cementing apparatus
CA 1267834 C · Owner: Easter, John Howard · Inventors: Easter, John Howard; Blandford, David M.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A stage cementing apparatus is disclosed which incorporates a stage cementing tool, a barrel and a mandrel for stage cementing of a casing within a wellbore. The apparatus can be moved between a closed position preventing cement from flowing therethrough to the exterior of the casing at the apparatus to an open position to permit cement to flow from the interior of the casing exterior the casing to cement the casing to the wellbore. The barrel and mandrel can have cooperating splines which are engaged in a position which corresponds to the closed position of the apparatus. When the splines are disengaged, the apparatus is open to permit cement flow exterior the apparatus and concurrent …
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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 17, 1990. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended April 17, 2007.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.