Gate valve
CA 2240308 C · Owner: Williams, Nicholas J. · Inventors: Williams, Nicholas J.; Clarkson, Curtis W.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A packingless gate valve is disclosed which includes a housing having opposed similar housing halves with primary resilient sleeve units which compressibly engage each other in the valve open condition and engage opposite sides of the gate in the valve closed condition. A secondary resilient seal unit is positioned above the primary sleeve units within the housing and is secured between the housing halves. The secondary seal unit engages the gate during the opening and closing cycles and prevents any discharge seeping between the primary sleeves from leaking to the atmosphere around the gate or on the actuator end of the valve. An enlarged clean out area cast into the housing extends …
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 June 11, 1998 and granted February 19, 2002. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended June 11, 2018.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by June 11, 2020.
- 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.