Patents by Inventor Pia Mellander

Pia Mellander 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).

  • Method for two-stage oxygen delignification of chemical pulp
    Patent number: 6454900
    Abstract: Methods for oxygen delignification of a pulp are disclosed, including initially delignifying the pulp at a delignification temperature of less than 90° C., adding oxygen to the pulp so that the oxygen is present during the initial delignification step, and further delignifying the pulp at a delignification temperature of greater than 90° C., the difference between the two delignification temperatures being less than about 20° C., and the pressure being greater in the initial delignification step. The method also includes adding alkali solely to the initial delignification step in order to obtain high alkalinity therein.
    Type: Grant
    Filed: June 21, 2001
    Date of Patent: September 24, 2002
    Assignee: Sunds Defibrator Industries AB
    Inventors: Monica Bokström, Pia Mellander, Solveig Nordén
  • Method for two-stage oxygen bleaching and delignification of chemical pulp
    Publication number: 20010052400
    Abstract: Methods for oxygen delignification of a pulp are disclosed, including initially delignifying the pulp at a delignification temperature of less than 90° C., adding oxygen to the pulp so that the oxygen is present during the initial delignification step, and further delignifying the pulp at a delignification temperature of greater than 90° C., the difference between the two delignification temperatures being less than about 20° C., and the pressure being greater in the initial delignification step. The method also includes adding alkali solely to the initial delignification step in order to obtain high alkalinity therein.
    Type: Application
    Filed: January 12, 2001
    Publication date: December 20, 2001
    Inventors: Monica Bokstrom, Pia Mellander, Solveig Norden
  • Method for two-stage oxygen bleaching and delignification of chemical pulp
    Patent number: 6319357
    Abstract: Methods for oxygen delignification of a pulp are disclosed, including initially delignifying the pulp at a delignification temperature of less than 90° C., adding oxygen to the pulp so that the oxygen is present during the initial delignification step, and further delignifying the pulp at a delignification temperature of greater than 90° C., the difference between the two delignification temperatures being less than about 20° C., and the pressure being greater in the initial delignification step. The method also includes adding alkali solely to the initial delignification step in order to obtain high alkalinity therein.
    Type: Grant
    Filed: January 12, 2001
    Date of Patent: November 20, 2001
    Assignee: Valmet Fibertech Aktiebolag
    Inventors: Monica Bokström, Pia Mellander, Solveig Nordén
  • Method for oxygen delignification of a digested pulp
    Publication number: 20010035272
    Abstract: Methods for oxygen delignification of a pulp are disclosed, including initially delignifying the pulp at a delignification temperature of less than 90° C., adding oxygen to the pulp so that the oxygen is present during the initial delignification step, and further delignifying the pulp at a delignification temperature of greater than 90° C., the difference between the two delignification temperatures being less than about 20° C., and the pressure being greater in the initial delignification step. The method also includes adding alkali solely to the initial delignification step in order to obtain high alkalinity therein.
    Type: Application
    Filed: June 21, 2001
    Publication date: November 1, 2001
    Inventors: Monica Bokstrom, Pia Mellander, Solveig Norden
  • Method for oxygen delignification of a digested pulp
    Patent number: 6221206
    Abstract: Methods for oxygen delignification of a pulp are disclosed, including initially delignifying the pulp at a delignification temperature of less than 90° C., adding oxygen to the pulp so that the oxygen is present during the initial delignification step, and further delignifying the pulp at a delignification temperature of greater than 90° C., the difference between the two delignification temperatures being less than about 20° C., and the pressure being greater in the initial delignification step. The method also includes adding alkali solely to the initial delignification step in order to obtain high alkalinity therein.
    Type: Grant
    Filed: September 11, 1997
    Date of Patent: April 24, 2001
    Assignee: Valmet Fibertech Aktiebolag
    Inventors: Monica Bokström, Pia Mellander, Solveig Nordén