Patents by Inventor Hans-Helmut Borggrefe

Hans-Helmut Borggrefe 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).

  • Method for recovering residual matter accumulated in the production and machining of steel
    Patent number: 4336218
    Abstract: A method of recovering particulate matter having a high metal content and including dust resulting from production of steel and chips from machining of steel. The method includes selecting the chips that have a length of 7 to 30 mm; mixing the dust and the selected chips in the ratio of about 70:20 to 30:60 pts/pts; wetting the dust, before or after it has been mixed with the chips, to a moisture content of 3 to 8% by weight to hydrate free lime in the dust; and mixing the dust and selected metal chips with a suitable binder; and forming the mixture into briquettes.
    Type: Grant
    Filed: October 22, 1980
    Date of Patent: June 22, 1982
    Inventors: Werner Kaas, Hans-Helmut Borggrefe, Klaus-Dieter Unger