Expired Canadian patentCanada
Acid rain neutralizing block, method of making such blocks and method of neutralizing acidified surface water
CA 2010352 C · Owner: National Gypsum Company · Inventors: Burke, W. Roy
Overview
Drawings and full text
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Blocks, weighing about 35 lbs. formed of a homogenous mixture of about 75% gypsum and 25% lime are, strategically placed in surface water that is being damaged by acid rain, where, by timed release of lime the pH of the water is maintained at about 6.5 pH.
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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 February 19, 1990 and granted July 7, 1998. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended February 19, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by February 19, 2012.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledFebruary 19, 1990
GrantedJuly 7, 1998
Term endedFebruary 19, 2010
Patent numberCA 2010352 C
Classification (IPC)C02F1/66 +1 more
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.