Manufacture of vitreous silica product
CA 2103870 C · Owner: Chandross, Edwin Arthur · Inventors: Johnson, David Wilfred, Jr.; Macchesney, John Burnette; Fleming, Debra Anne
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Lowered cost fabrication including preparation of large bodies of void-free high-silica glass, depends upon gellation of an aqueous sol of colloidal silica particles, followed by drying and firing of such gel. Freedom from cracks in thedried gel is the consequence of included polymeric material which wets the particles. The polymeric material is removed by thermal decomposition attended upon temperature attained in firing.
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 August 11, 1993 and granted September 15, 1998. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended August 11, 2013.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by August 11, 2015.
- 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.