Mud check valves in drilling apparatus (wells)
CA 2124676 C · Owner: Appleton, Robert Patrick · Inventors: Appleton, Robert Patrick; Appleton, Robert Patrick
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A check valve for connection with the top end of a drillstring as a mud saver comprises a tubular valve member (18) which is axially shiftable within a tubular , body (10) through a sleeve seal (19) which is mounted in the body (10) and which cooperates with ports in the wall of the tubular valve member (18) and which is disposed adjacent a downstream end of the tubular valve member. A compression spring (20) urges the tubular valve member (18) in the upstream direction into abutment with an upstream stop (15). The downstream end of the tubular valve member is closed by means of a frangible glass disc (21). The sleeve, seal (19) is also axially shiftable in the body (10) in an upstream …
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 November 27, 1992 and granted January 23, 2001. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended November 27, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 27, 2014.
- 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.