Differential eddy current internal inspection probe, arrayed probe, and defect inspection device and method

A differential eddy current internal inspection probe, comprising an excitation coil, a first receiving coil, and a second receiving coil;

• wherein,
• the excitation coil is located between the first receiving coil and the second receiving coil, the first receiving coil and the second receiving coil are symmetrically attached to both sides of the excitation coil, and bottom surfaces of the first receiving coil, the excitation coil and the second receiving coil are located in a same plane to form a bottom surface of the differential eddy current internal inspection probe;
• the excitation coil is energized with an alternating current to generate induced eddy current fields in an inspected pipeline;
• the first receiving coil and the second receiving coil are opposite in winding direction;
• the first receiving coil is configured to receive an induced magnetic field generated by an induced eddy current field at a first position of the inspected pipeline and to output a first voltage signal;
• the second receiving coil is configured to receive an induced magnetic field generated by an induced eddy current field at a second position of the inspected pipeline and to output a second voltage signal;
• the first position is a position, corresponding to a position of the first receiving coil, in the inspected pipeline, and the second position is a position, corresponding to a position of the second receiving coil, in the inspected pipeline;
• and
• the differential eddy current internal inspection probe is located in the inspected pipeline, and the bottom surface of the differential eddy current internal inspection probe is parallel to an axis of the inspected pipeline;
• when the inspected pipeline is subjected to direct current magnetization, the differential eddy current internal inspection probe is configured to inspect inner surface defects, buried defects and outer surface defects of the inspected pipeline based on a difference value between the first voltage signal and the second voltage signal;
• and when the inspected pipeline is not subjected the direct current magnetization, the differential eddy current internal inspection probe is configured to inspect the inner surface defects of the inspected pipeline based on the difference value between the first voltage signal and the second voltage signal;
• and types of the inner surface defects, buried defects and outer surface defects comprise cracks and corrosion.