Differential pressure operated circulating and deflation valve
CA 2106698 C · Owner: Zimmerman, John Chris · Inventors: Tucker, James C.; Zimmerman, John Chris; Walter, Jeffrey S.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A differential pressure operated valve for use as a circulating and/or deflation valve in a well bore. The valve comprises a housing defining first and second bores therethrough and a passage providing communication between the interior and exterior of the housing. A valve sleeve is slidably disposed in the housing and has a first outer surface slidably disposed in the first bore and a second outer surface slidably disposed in the second bore. A valve port is defined in the valve sleeve providing communication between a central opening thereof and the passage in the housing when the valve sleeve is in an open position. When the valve sleeve is closed, the valve port and passage are isolated …
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 22, 1993 and granted November 11, 1997. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended September 22, 2013.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by September 22, 2015.
- 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.