The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 25, 2012
Filed:
Feb. 16, 2011
Akira Nishimizu, Tokai, JP;
Yoshio Nonaka, Hitachi, JP;
Isao Yoshida, Hitachi, JP;
Motoyuki Nakamura, Hitachi, JP;
Akihiro Taki, Hitachi, JP;
Masahiro Koike, Hitachi, JP;
Akira Nishimizu, Tokai, JP;
Yoshio Nonaka, Hitachi, JP;
Isao Yoshida, Hitachi, JP;
Motoyuki Nakamura, Hitachi, JP;
Akihiro Taki, Hitachi, JP;
Masahiro Koike, Hitachi, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
The surface length of a metal subject to be inspected is evaluated by detecting an eddy current without using a combination of a scale and visual or liquid penetrant inspection. An exciting coil and a detecting coil are scanned above the subject in a length direction. An eddy current detector measures an output voltage corresponding to scanning positions based on an output from the detecting coil. Based on an output voltage distribution curve indicating a distribution of output voltages corresponding to the scanning positions, position information is extracted corresponding to values which are within a differential voltage range and lower by 12 dB than a maximum value of the output voltages on the left and right sides of the distribution. A distance between the positions included in the extracted information is calculated to evaluate the length of a slit which is a defect present on the subject surface.