Method for purifying nitrogen trifluoride gas
CA 2001304 C · Owner: Mitsui Toatsu Chemicals, Inc. · Inventors: Aritsuka, Makoto; Iwanaga, Naruyuki
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A method is provided herein for purifying a nitrogen trifluoride gas. The method includes the steps of thermally treating a natural zeolite, e.g. analcime clipnoptilolite, mordenite, ferrierit, phillipsite chabazite, erionite and laumontite, at a temperature of 250° to 700°C. A packed bed is then formed of such treated zeolite. The nitrogen trifluoride gas containing N2F2 in the amount of 0.2 to 0.6% as gaseous impurities is then passed through the packed bed at a temperature of -125° to 50°C. .
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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 October 24, 1989 and granted June 23, 1998. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended October 24, 2009.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by October 24, 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
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.