Method and apparatus for making highly oxidized lead powder
CA 2005207 C · Owner: Yasuda, Hiroshi · Inventors: Takahashi, Katsuhiro; Yamamoto, Kenzo; Yasuda, Hiroshi
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A method for producing highly oxidized lead powder containing red lead in a desired content is efficiently performed in a rotary kiln furnace having a high temperature zone and a low temperature zone, wherein a maturing oxidation of a raw lead powder containing metallic lead and litharge is performed with spontaneous rise in temperature while spraying water on said material to control said spontaneous rise in temperature in the low temperature zone of said furnace and then heating the resultant product of the maturing oxidation to a temperature above the temperature of the maturing oxidation, in the high temperature zone of said furnace, to produce the desired content of red lead.
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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 December 12, 1989 and granted June 30, 1998. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended December 12, 2009.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by December 12, 2011.
- 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
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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.