Patents by Inventor Friedhelm Vennmann

Friedhelm Vennmann 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: 4399545
    Abstract: A method of lowering graphite electrodes which are supported vertically displaceable electrode holders and extend through the cover of an electric arc furnace is disclosed. In accordance with the disclosed method, the furnace cover is completely laterally swung away from the furnace vessel and then the free lengths of the electrodes below the electrode clamps are adjusted to a position insuring a stable electric arc.
    Type: Grant
    Filed: June 23, 1981
    Date of Patent: August 16, 1983
    Assignee: M.A.N. Maschinenfabrik Augsburg-Nurnberg
    Inventors: Lothar Harmsen, Friedhelm Vennmann, Jurgen Zieschang
  • Patent number: 4351055
    Abstract: A water cooled wall element for at least partially replacing the casing of refractory material in melting furnaces, especially electric arc furnaces for melting steel, above the bath of molten material in the furnace comprises a plurality of parallel, horizontally extending and vertically superimposed tubes abutting against each other, a cooling water inlet connected to the lowermost of the superimposed tubes, a cooling water outlet connected to the uppermost tube, and return bends connecting the ends of proximal tubes to each other so that the cooling water will flow from the cooling water inlet through the plurality of superimposed tubes to the cooling water outlet, wherein elongated substantially uninterrupted protrusions are provided on each of the tubes and extending in the longitudinal direction thereof on that surface of the wall element which is directed toward the interior of the surface to increase adhesion of an insulating layer of refractory material to be applied to the inner surface of the wall
    Type: Grant
    Filed: March 24, 1980
    Date of Patent: September 21, 1982
    Assignee: Benteler Werke AG
    Inventors: Klaus Bick, Lothar Harmsen, Jurgen Zieschang, Friedhelm Vennmann
  • Patent number: 4275258
    Abstract: A box-shaped shallow, water-cooled element of steel plate for the construction of a wall portion of a melting furnace above the melt in the furnace, has a front wall adapted to face the interior of said furnace. This front wall is provided with a plurality of recesses of equal cross-section equally spaced from each other in the form of elongated grooves or bores to facilitate adhesion of a layer of refractory material to be applied thereto, wherein the recesses are machined in the surface of the front wall adapted to be directed to the interior of the furnace in such a manner that the area of recesses at this surface is smaller than the area of the remaining non-machined surface to thus enhance heat conduction from the interior of the furnace to the cooling water passing through the wall element and to prevent damage of the front wall when the protective layer is missing completely or in part.
    Type: Grant
    Filed: May 31, 1979
    Date of Patent: June 23, 1981
    Assignee: Benteler-Werke AG
    Inventors: Lothar Harmsen, Klaus Bick, Wilhelm Lachenmayer, Friedhelm Vennmann, Jurgen Zieschang