Patents by Inventor Frederick A. Hoffstadt

Frederick A. Hoffstadt 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).

  • Frother for coal flotation
    Patent number: 4272364
    Abstract: Use of 4,4-dimethyl-1-pentanol as a froth flotation agent for coal recovery processes.
    Type: Grant
    Filed: March 24, 1980
    Date of Patent: June 9, 1981
    Assignee: Calgon Corporation
    Inventors: Kenneth W. Dixon, Frederick A. Hoffstadt