Water pumping apparatus utilizing compressed air
CA 2224054 C · Owner: Nagata, Tsugio · Inventors: Nagata, Tsugio
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A method of and device for providing compressed air of this invention comprise: a vessel proper (1) having an air chamber that can hermetically seal air therein, and being in structure capable of reducing the internal volume of said air chamber correspondingly to the external hydraulic pressure; a compressed air recovery vessel (30) connected to said air chamber through a check valve (32), into which vessel the compressed air is fed under pressure when the internal volume of said air chamber (12) is reduced correspondingly to the external hydraulic pressure; and a weight (40) fixed to these vessels forenabling these vessels to sink into water. A water pumping device of this invention using …
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 July 2, 1991 and granted February 26, 2002. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended July 2, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by July 2, 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.