Patents by Inventor Helmut Preyer

Helmut Preyer 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).

  • Gas purging device
    Patent number: 5437435
    Abstract: The present invention pertains to a gas purging device for introducing gases and/or solid reactants into the metal melt of a metallurgical crucible, consisting of a gas purging plug, a well nozzle sleeve surrounding it, and/or a well nozzle surrounding the plug or the nozzle brick, with a mounting device arranged in the area of the respective end face.
    Type: Grant
    Filed: September 7, 1993
    Date of Patent: August 1, 1995
    Assignee: Radex-Heraklith Industriebeteiligungs Aktiengesellschaft
    Inventors: Lorenz Dotsch, Karl-Heinz Hofer, Helmut Preyer
  • Process for producing a gas purging plug with increased resistance to infiltration and oriented porosity
    Patent number: 5225247
    Abstract: A process for producing a plug with increased resistance to infiltration and oriented porosity for use in metallurgical melting crucibles, in which the matrix material of the plug is subjected to an impregnating treatment.
    Type: Grant
    Filed: July 17, 1991
    Date of Patent: July 6, 1993
    Assignee: Radex-Heraklith Industriebeteiligungs Aktiengesellschaft
    Inventors: Lorenz Dotsch, Helmut Preyer, Frich Renfordt, Jean-Louis Retrayt