Patents by Inventor Harriet E. Hofmann

Harriet E. Hofmann 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: 4060424
    Abstract: Refractory materials with high sintering temperatures are made suitable for use as low temperature setting dry vibration cements, ramming cements, gunning cements, and the like by incorporation therein of up to 4% boric acid and a low temperature softening glass or frit. The lower temperature softening frit is finely ground and uniformly mixed with a refractory grain or aggregate. When the mixture is subjected to a temperature as low as 350.degree. C, the frit softens and bonds the refractory grain into a monolithic structure which retains its integrity up to and through the elevated temperatures at which the refractory grains sinter and other high-temperature ceramic bonds form.
    Type: Grant
    Filed: February 3, 1976
    Date of Patent: November 29, 1977
    Assignee: Norton Company
    Inventor: Harriet E. Hofmann