Patents by Inventor Carl Ryffel

Carl Ryffel 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).

  • Asbestos-free filtering layer
    Patent number: 4149975
    Abstract: Equal or better adsorbency at lower cost is obtained with a sheet filter of the type having a filtering layer comprised of a supporting layer formed of at least one fibrous material with at least one adsorbent material evenly distributed within the supporting layer, when the adsorbent material consists essentially of .gamma.-aluminum oxide instead of asbestos. A supplementary organic adsorbent material can be incorporated together with an inorganic filler such as kaolin or kieselguhr.
    Type: Grant
    Filed: September 27, 1977
    Date of Patent: April 17, 1979
    Assignee: Filtrox-Werk AG
    Inventors: Ernst Keim, Istvan Laczko, Carl Ryffel