Process of phosphating metal surfaces
CA 2003270 C · Owner: Siemund, Gunter · Inventors: Vey, Rudolf; Oei, Han-Yong; Siemund, Gunter
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
During a phosphating of metal surfaces which consist at least in part of iron or steel and are dipped into or flooded with phosphating solutions which contain layer-forming cations and nitrate or equivalent accelerators, the iron content is limited by a precipitation of iron phosphate. A partial volume of the phosphating solution is intermittently whithdrawn from the bath tank and in a separate earator is contacted with oxygen or oxygen-containing gas. The iron phosphate sludge is removed from the resulting solution, which is then returned to the bath tank. The partial volume of the phosphating solution is supplied from below into and is aerated in an aerator which, is provided with an …
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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 November 17, 1989 and granted February 2, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended November 17, 2009.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 17, 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.
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.