Patents by Inventor Rolf Berthelius

Rolf Berthelius 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).

  • Foil element
    Patent number: 4797537
    Abstract: A foil element for the electric heating of objects comprises a resistance heating coil placed between insulating plastic foils and a sensor coil placed between the plastic foils beside the heating coil. The sensor and heating coils are formed of the same metallic material. The sensor coil is spaced sufficiently far from the heating coil to assure that the sensor coil is heated mainly by heat flowing to or from the object being heated and only slightly by heat directly from the heating coil. The electric resistance of the sensor coil is sensed to determine the temperature thereof. The heating coil is controlled in accordance with the temperature of the sensor coil.
    Type: Grant
    Filed: December 10, 1986
    Date of Patent: January 10, 1989
    Assignee: Kanthal AB
    Inventors: Rolf Berthelius, Tommy Fredriksson