Patents by Inventor Friedrich O. B. Ludhe

Friedrich O. B. Ludhe 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).

  • Apparatus for the treatment of lignocellulosic material
    Patent number: RE31862
    Abstract: The invention relates to the production of a wholly mechanical pulp of improved strength properties. The lignocellulosic material is fed into a substantially closed chamber where it is mechanically abraded under a power input of fifteen or more horsepower days per ton. During the abrading step, the material is maintained in an inert gaseous atmosphere of a pressure of ten to eighty psig, preferably twenty to forty psig.
    Type: Grant
    Filed: March 22, 1983
    Date of Patent: April 9, 1985
    Assignee: Sunds Defibrator, Inc.
    Inventors: Kenneth C. Logan, Friedrich O. B. Ludhe