Graphite packing with ptfe discs
CA 2058265 C · Owner: Scheffert, William Charles · Inventors: Brestel, Ronald Ray; Funk, Ronnald James; Scheffert, William Charles
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A fluid valve graphite packing assembly with graphite packing rings and thin PTFE disc rings surrounding an operating valve member. Softer graphite packing rings on the interior are,bounded by progressively harder graphite packing rings. A PTFE disc ring is inserted between the graphite packing rings. The packing is subjected to sufficient packing stress to cause the PTFE disc rings to extrude onto the operating valve member.
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 December 20, 1991 and granted October 31, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended December 20, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by December 20, 2013.
- 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.