Patent ID: 8203336

Claim:
An eddy current probe having a magnetic gap, comprising: a high flux magnetic core, said high flux magnetic core having an annular gap at a face of said high flux magnetic core configured to face a tubal object wherein said annular gap is smaller than 800 micrometers (μm); an excitatory coil, said excitatory coil winding around said high flux magnetic core, said excitatory coil generating an eddy current in said tubal object by a part of said excitatory coil, said part of said excitatory coil being revealed toward said annular gap facing said tubal object; a support part, said support part supporting and fixing said excitatory coil; and a detection part, said detection part exciting said excitatory coil to generate a high-frequency magnetic field, said detection part obtaining signals of said excitatory coil to analyze impedance changes of said excitatory coil, wherein a particular magnetic field lines loop is obtained to limit a magnetic field by said annular gap to detect said tubal object for defects of perforation, crevices, or transmutation.