Patents by Inventor K. Solveig E. Norden

K. Solveig E. Norden has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Chlorine dioxide bleaching of chemical pulp
    Patent number: 5589031
    Abstract: A method of bleaching chemical pulp in a sequence comprising at least four bleaching steps with final bleaching in a first and a second chlorine dioxide step. Between the chlorine dioxide steps an alkaline extraction is carried out, and washing takes place between the first chlorine dioxide step and extraction. Immediately after said washing step, NaOH is charged in an amount of 4-10 kg/ton pulp. Thereafter an oxidizing agent is admixed in an amount of at maximum 2 kg/ton pulp. After 15-120 seconds an acid is added for terminating the oxidation treatment and for lowering the pH-value, but without effecting a complete neutralization of residual alkaline.
    Type: Grant
    Filed: October 2, 1992
    Date of Patent: December 31, 1996
    Assignee: Sunds Defibrator Industries Aktiebolag
    Inventors: Per-.ANG.ke Farnstrand, Lars T. Sjodin, Lars-.ANG.ke Lindstrom, K. Solveig E. Norden