Patents by Inventor James Keith Hartman

James Keith Hartman 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: 4019113
    Abstract: An energy conversion device is described which efficiently converts thermal energy to electrical energy or electrical energy to thermal energy through the mechanism of a structure which includes a first element (cathode), usually a metal, a second material such as an insulator or a semiconductor providing a voltage barrier and a conduction band, and a third material (anode), usually a metal, where the voltage barrier between the first element and the second element is greater than the voltage barrier between the second element and the third element. In some metals, work function is a relative indicator of voltage barrier heights and may be used as a criterion for selection of metals for the first and third elements, once the second element has been chosen.
    Type: Grant
    Filed: November 20, 1974
    Date of Patent: April 19, 1977
    Inventor: James Keith Hartman