Efficient production of landplaster by collecting and classifying gypsum fines
CA 2201540 C · Owner: Cgc Inc. · Inventors: Voorberg, Dennis B.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A landplaster production method includes the steps of providing a supply of particulate gypsum material, drying the gypsum material by passing a stream of heated air thereby as the material is rotated classifying and separating the dried particles into fines and coarse particles, collecting the suspended fines in a collector passing the coarse, particles to a grinder such as a roller mill for reducing the particles and mixing the, reduced particles with the collected fines for processing into landplaster. The elimination of fines from the feed to the grinder results in significantly greater production by increasing the efficiency of the grinder. Further the dryer is modified to agitate the …
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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 April 2, 1997 and granted February 18, 2003. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended April 2, 2017.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by April 2, 2019.
- 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.