Expired Canadian patentCanada
Recovery of sulphurous acid and heat
CA 233159 A · Owner: The Zellstofffabrik Waldhof · Inventors: Carl Hangleiter; Hans Clemm
Overview
Drawings and full text
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordRead 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
- Granted July 31, 1923. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended July 31, 1940.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Filed—
GrantedJuly 31, 1923
Term endedJuly 31, 1940
Patent numberCA 233159 A
Classification (IPC)D21C11/00
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.