Patents by Inventor Franc Schellberg

Franc Schellberg 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).

  • Patent number: RE33700
    Abstract: Parts subject to wear, which come into contact with metal melts, are formed with a hydraulically setting high-alumina refractory concrete having a compression strength when cold, measured on dried crude product, of at least 400 kp/cm.sup.2. The compression strength is at least 700 kp/cm.sup.2 after firing at 1400.degree. C. The refractory concrete has a dimensional stability at 1400.degree. C. of at least plus or minus 0.2%. The refractory concrete contains corundum and active alumina as aggregates, an alumina .[.concrete.]. .Iadd.cement .Iaddend.containing less than 22% lime and, as required, a thinning agent. Up to 5% of the aggregates can be replaced by a spinel-forming substance preferably MgO or MgO-yielding compounds; or up to 5% of the aggregates can be replaced by carbon black, pitch or graphite; or up to 7% of the aggregates can be replaced by chromium oxide. Aggregates under 0.5 mm can be present in the refractory concrete as round grains.
    Type: Grant
    Filed: December 9, 1987
    Date of Patent: September 24, 1991
    Assignee: Didier-Werke AG
    Inventors: Gunter Gelsdorf, Hermann Leupold, Franc Schellberg