N-shaped backflow preventor
CA 2082953 C · Owner: Dunmire, Charles W. · Inventors: Dunmire, Charles W.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A backflow preventor with increased performance and increased ease of installation is provided. The check valves (12 14), are configured to assist in redirecting flow along the desired pathway when they are in the open position. The pathway is designed so that the number of changes of flow direction of the average streamline flow is reduced preferably being about 180, degrees. The check valves (12 14) are configured to reduce or eliminate divergent flow around the edges of the valve disks (32 72). A check valve (12, 14) with a reduced hold-open pressure includes a biasing device such as a spring (52,74) directly connected to a pivoting clapper (32, 72) as one end (64 66) and to the 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 January 21, 1992 and granted September 15, 1998. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended January 21, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by January 21, 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.