Patents by Inventor Ewa W. Johansson

Ewa W. Johansson 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).

  • Pulp production
    Patent number: 5593544
    Abstract: A method of manufacturing chemical pulp out of comminuted cellulosic fiber material comprising digesting the fiber material with digestion liquid without preceding peroxide stage. According to the invention the comminuted fiber material is treated in at least one stage prior to said digestion, in the presence of a liquid containing at least one compound having the ability to form complexes with metals existing naturally in the fiber material.
    Type: Grant
    Filed: April 8, 1994
    Date of Patent: January 14, 1997
    Assignee: Kvaerner Pulping Aktiebolag
    Inventors: Christer Fahlgren, Soren Gustavsson, Petter Tibbling, Ewa W. Johansson