Pulse cathodic protection system
CA 2076741 C · Owner: Doniguian, Thaddeus M. · Inventors: Doniguian, Thaddeus M.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A circuit and method of cathodically protecting ferrous metal structures such as pipelines or well casings is described disposed in a conductive medium such as the ground. A pair of terminals are connected to an anode spaced from the structure and to the structure. A source of d.c. voltage is periodically connected across the terminal to cause current to flow to the anode and provide electrons at the surface of the structure to inhibit ferrous molecules from going into solution and damaging the integrity of the structure. The current flow due to the induced emf caused by the reactive inductions of the anode/cathode system is limited to inhibit damage to neighboring ferrous structures by …
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 August 24, 1992 and granted May 19, 1998. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended August 24, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by August 24, 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.