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Expired Canadian patentCanada

Method and apparatus in a paper machine for regulating pressure in the space between a headbox lip beam and breast roll

CA 1255528 A · Owner: Valmet Oy · Inventors: Pitkajarvi, Kari

CIPO record

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

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Abstract From the Canadian patent

Method and apparatus for regulating pressure in a wedge-shaped space between the wall of the headbox lip beam or the like and the breast roll. An arrangement is provided by which air jets are directed in a direction opposite to the direction in which the forming wire moves on the breast roll to eject air out of the wedge-shaped space to maintain the pressure induced therein at a desired level. The apparatus includes a blow box coupled to a source of pressurized air and the box having a wall in opposed relationship to the forming wire in which nozzle openings or slots are formed through which the air jets are directed. The blow box has a wider side which substantially closes the wedge-shaped …

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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 June 13, 1989. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended June 13, 2006.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledOctober 24, 1985
GrantedJune 13, 1989
Term endedJune 13, 2006
Patent numberCA 1255528 A
Classification (IPC)D21J7/00 +1 more

Timeline

Timeline From CIPO dates

1986198919921995199820012004Application filedOct 24, 1985Patent grantedJune 13, 1989Term endedJune 13, 2006

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