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Expired Canadian patentCanada

Thermal stabilizing system for a headbox of a paper machine

CA 1236722 A · Owner: Ahlstrom (A.) Osakeyhtio · Inventors: Laitinen, Sakari; Nyman, Tapani

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

The outer walls of the beams of a papermachine headbox are heated by means of heat transferred from the stock to a temperature equal to that of the inner walls in contact with the stock. This is preferably carried out so that the liquid which is circulated in a closed liquid circulation through liquid spaces adjoining the outer walls is caused, to be in indirect heat transfer contact with the stock. Fig. 1.

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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 May 17, 1988. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended May 17, 2005.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledApril 24, 1984
GrantedMay 17, 1988
Term endedMay 17, 2005
Patent numberCA 1236722 A
Classification (IPC)D21F1/02

Timeline

Timeline From CIPO dates

1985198819911994199720002003Application filedApril 24, 1984Patent grantedMay 17, 1988Term endedMay 17, 2005

Sources & verification

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