Low resistance electrical heater
CA 2055548 C · Owner: Van Egmond, Cornelis Franciscus Henricus · Inventors: Van Egmond, Cornelis Franciscus Henricus
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A subterranean electrical heater comprising an electrical heating cable (9, 10) arranged in a partly cased well borehole (1) having a heating core comprising about 6 percent by weight of nickel and about 94 percent by weight of copper a mineral, insulation surrounding the heating core a sheath surrounding the, mineral insulation cement (23) securing the heating cable (9 10), in the well borehole (1) in the formation zone (22) to be heated; and a means (1, 2) to supply electrical power through the heating cable (9, 10).
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 November 14, 1991 and granted May 8, 2001. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended November 14, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 14, 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.