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:
May. 03, 1988
Filed:
Sep. 16, 1986
Seigo Ando, Yokohama, JP;
Toshiaki Hosoe, Yokosuka, JP;
Nippon Kokan Kabushiki Kaisha, Tokyo, JP;
Abstract
An apparatus for detecting a surface flaw of each pipe constituting a pipeline, including a pig capable of travelling along pipeline and being provided with the following elements: a cylindrical primary coil coaxial with the pipe, the density of a magnetic flux of an AC magnetic field of the primary coil varying in response to an inner surface flaw of the pipe; a plurality of cylindrical secondary coils arranged at prescribed intervals in the circumferential direction of the pipe between a peripheral surface of the primary coil and a confronting peripheral surface of the pipe, each secondary coil having an axis parallel to the axis of the primary coil, and producing an AC voltage proportional to the density of a component parallel to the axis of each secondary coil, of the magnetic flux of the AC magnetic field of the primary coil; and a signal processing circuit for processing the AC voltage signals from the secondary coils to detect the presence and the depth of a surface flaw of the pipe.