Cathode protection
CA 2010316 C · Owner: Comalco Aluminium Limited · Inventors: Juric, Drago D.; Shaw, Raymond W.; Watson, Kevin D.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A method of operating an aluminium smelting cell during the start-up phase of the cell comprising forming a layer of boron oxide on the exposed surface of the cathode of the cell, forming a layer of aluminium on the boron oxide layer, said boron oxide layer forming a barrier impervious to oxygen at temperature from 400°C to about 650°C and said, aluminium layer forming a barrier to oxygen at temperatures above about 600°C up to temperatures of about 1000°C thereby reducing the development of oxidation products in the cathode during cell start-up.
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 February 19, 1990 and granted April 11, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended February 19, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by February 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.