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Expired Canadian patentCanada

Roll and blade twin-wire gap former for a paper machine

CA 2228259 C · Owner: Valmet Corporation · Inventors: Odell, Michael; Verkasalo, Lauri

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

A roll and blade gap former for a paper machine having first and second wires guided in a respective loop and defining a twin-wire forming zone a forming , gap in which the first and second wires converge before the twin-wire zone a , headbox including a slice channel having a slice opening through which a stock suspension jet is fed into the forming gap to form a web between the wires and drainage and forming elements arranged in the twin-wire zone for removing water from the web. To provide an improvement in the control of the Zdirection properties of the web, the former includes turbulence generating vanes arranged in the slice channel in the headbox to cause turbulence in the stock …

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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 June 10, 1997 and granted December 7, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended June 10, 2017.
  • A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by June 10, 2019.
  • 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 10, 1997
GrantedDecember 7, 1999
Term endedJune 10, 2017
Patent numberCA 2228259 C
Classification (IPC)D21F1/00 +1 more

Timeline

Timeline From CIPO dates

1998200020022004200620082010201220142016Application filedJune 10, 1997Patent grantedDec 7, 1999Term endedJune 10, 2017

Sources & verification

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