Corrosion inhibition apparatus for downhole electrical heating
CA 2012327 C · Owner: Bridges, Jack E. · Inventors: Bridges, Jack E.; Bajzek, Thomas J.; Dubiel, George T.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Corrosion inhibition apparatus in an, electromagnetic heating system for in situ downhole heating in an oil well or other mineral fluid well that includes an A.C. power source for a high amperage, low frequency heating current (e.g. over 50 amperes at 0.01 to 35 Hz) and a D.C. bias source for generating a low amplitude (e.g. less than one ampere) current for corrosion inhibition both sources, connected to a downhole electrode. The bias source includes at least one semiconductor device, connected in the main A.C. heating circuit in a bias circuit that develops a net D.C. voltage differential of the polarity required for corrosion inhibition in response to the A.C. heating current.
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 15, 1990 and granted November 8, 1994. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended March 15, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by March 15, 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.