Method and apparatus for hot top casting of reactive metals
CA 2047384 C · Owner: Norsk Hydro A.S. · Inventors: Larsen, Ivar Oystein; Kittilsen, Bjorn; Klovland, Jan Ivar
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Method and apparatus for use in hot top continuous casting of reactive metals, especially magnesium and magnesium containing alloys. To prevent oxidation a protective gas is supplied to the porous refractory hot top material (1) and eventual joints. It is arranged a closed chamber (7) between hot top (1) and a jacket (8) for supply of gas. It is preferred to use sulphur hexafluoride eventually in mixture with other gases.
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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 July 18, 1991 and granted September 9, 1997. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended July 18, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by July 18, 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
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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.