Method and apparatus for calendering paper with internally heated roll
CA 2097724 C · Owner: S.D. Warren Services Company · Inventors: Mattor, John A.; Jewett, Kenneth B.; Harrington, Joyce M.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Disclosed is a new internally heated calendering roll capable of finishing paper satisfactorily at the temperatures heat loads and pressures required for substrata thermal molding. The roll is internally heated and has a circumferential wall at least 4 inches thick. It includes means to provide heat into the interior of the circumferential wall to be conducted through the wall to the outer surface for heating the paper web being calendered by the roll. The roll is constructed of a first material with a thin circumferential surface layer of a second, cermet or ceramic containing material. The surface layer material has a hardness of at least 530 Vickers and a thickness of between .003 inch …
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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 May 13, 1992 and granted December 2, 1997. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended May 13, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by May 13, 2014.
- 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.