Patents by Inventor Nicholaas T. Van Der Walt

Nicholaas T. Van Der Walt 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).

  • Method and apparatus for detecting cross sectional area variations in a elongate object by measuring radial magnetic flux variations using spaced-apart coils
    Patent number: 4929897
    Abstract: A method and apparatus is provided for electromagnetically testing an elongate object such as a wire rope for cross-sectional area variations. The elongate object is magnetized over adjacent sections in opposing directions along a longitudinal axis of the elongate object. Variations in axial magnetic flux, which have been observed to be coincident with variations in the cross-sectional area of an elongate object, are measured by using saddle coils which are positioned adjacent the magnetized sections of the elongate object and which detect variations in radial flux. The saddle coils are positioned to have first half circumferential windings located where the magnetic flux density in the elongate object is at a maximum value and second half circumferential windings located where the magnetic flux density in the object is zero.
    Type: Grant
    Filed: November 18, 1988
    Date of Patent: May 29, 1990
    Assignee: Crucible Societe Anonyme
    Inventor: Nicholaas T. Van Der Walt