Automatic back water valve system
CA 2284741 C · Owner: Cook, William H. · Inventors: Cook, William H.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A valve body (15) is formed of two half sections (16 18) which are secured , together to define a drain line passage (12) and to confine therebetween a thin gate valve (45) between a lower open position and an upper closed position. Actuator (110) includes flexible bellows (80) confined between a cylindrical wall (88) and cover (110). Valve body (15) and bellows (80) define an expandible chamber connected by a bottom port or extension line (97) to the drain line (12). If sewage water backs up air within the fluid chamber , expands bellows (80) upwardly to close valve (45). When sewage water flows from the drain line (12), bellows (80) moves downwardly due to differential pressure and …
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 March 24, 1998 and granted December 24, 2002. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended March 24, 2018.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by March 24, 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.