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Expired Canadian patentCanada

Continuous gypsum kettle

CA 1087367 A · Owner: National Gypsum Company · Inventors: O'Connor, Francis J.

CIPO record

Overview

Drawings and full text

Its claims, description and drawings are in the Canadian Patents Database.

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Abstract From the Canadian patent

Continuous calcination of gypsum is provided by uniformly feeding uncalcined gypsum into the calcining batch in a kettle to a location below the surface but above the uppermost agitator, and allowing calcined gypsum to be discharged from the kettle through a discharge outlet in the wall of the kettle at the top surface of the calcining gypsum.

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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

  • Granted October 14, 1980. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended October 14, 1997.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledJune 1, 1977
GrantedOctober 14, 1980
Term endedOctober 14, 1997
Patent numberCA 1087367 A
Classification (IPC)F27B9/30 +2 more

Timeline

Timeline From CIPO dates

1978198019821984198619881990199219941996Application filedJune 1, 1977Patent grantedOct 14, 1980Term endedOct 14, 1997

Sources & verification

Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.