Patents by Inventor Heljar Hovland

Heljar Hovland 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: 5069005
    Abstract: The present invention relates to a method for detecting flaws and surface defects in metallic workpieces, particularly in non-magnetic steel workpieces. The surface of the workpiece is heated by passing the workpiece in its longitudinal direction through an induction coil, scanning the surface of the workpiece with an infrared camera transversely across the surface of the moving workpiece immediately after induction heating and recording a streaked pattern temperature profile in which the streaked pattern repeats itself where there are flaws in the surface. It is used an induction coil with a current frequency which gives a penetration depth of the induced current in the workpiece which is greater than the depth of the flaws which are to be detected. The flaws and surface defects are detected by recording a lower surface temperature than the rest of the surface of the workpiece by scanning the temperature profile immediately after induction heating.
    Type: Grant
    Filed: December 18, 1989
    Date of Patent: December 3, 1991
    Assignee: Elkem Technology a/s
    Inventors: Heljar Hovland, Jan Nilsen, Yngve Strom