Drill string shutoff valve
CA 2483244 C · Owner: He, Xiaoping · Inventors: Movaffagh, Behrooz; Chan, Kwong-Onn C.; He, Xiaoping
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A valve assembly connects into a drill string for opening and closing a passage within the drill string. The valve assembly has an inner valve member for opening and closing an inner passage of the drill string. The valve member moves between the open and closed positions in response to axial movement of the drill string. Lifting the drill string causes the upper portion to move upward relative to the lower portion bringing along with it the valve member while the valve sleeve remains stationary with the lower portion opening the valve. The valve assembly can include an annular valve assembly for opening and closing an annular passage located around the inner passage. The annular valve …
Read the whole patent
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
- Filed September 30, 2004 and granted May 29, 2012. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended September 30, 2024.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by September 30, 2026.
- 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.