Patents by Inventor James E. Crews

James E. Crews 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).

  • Self regulating PTCR heater
    Patent number: 4574187
    Abstract: A self regulating ceramic PTCR (positive temperature coefficient of resistance) heater has a pair of spaced interdigitated electrodes on one major surface of a ceramic PTCR plate. A heat transfer means is provided for extracting heat from the opposite major surface of the PTCR plate. Best heating efficiency is obtained when the thickness of the PTCR plate is about the same or is less than the average spacing between the electrodes.
    Type: Grant
    Filed: August 29, 1980
    Date of Patent: March 4, 1986
    Assignee: Sprague Electric Company
    Inventors: James E. Crews, George H. Rodriguez