Four-way valve
CA 2046924 A1 · Owner: Phillips, Edward H. · Inventors: Phillips, Edward H.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A four-way open-center rotary control valve (210 260) is, provided which features internally generated hydraulic reaction torque. The hydraulic reaction torque is generated between inner (212 262) and outer valve members (214, 264) having multiple inlet (220 222) and return control orifices (232, 234) formed at differing radii. The return control orifices are formed at larger radii than the inlet control orifices - thereby resulting in expanded values of radially disposed area on either side of ridges which partially form the return control orifices. Thus differential output , pressure present in first and second output zones which are, alternately disposed between pairs of the inlet …
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 19, 1990. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended March 19, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by March 19, 2012.
- 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.