Coil self-excitation-based ferromagnetic pipeline electromagnetic ultrasonic transducer, excitation device and receiving device

Abstract

The invention discloses a coil self-excitation-based ferromagnetic pipeline electromagnetic ultrasonic transducer, an excitation device and a receiving device. The coil self-excitation-based ferromagnetic pipeline electromagnetic ultrasonic transducer a frame, a normal-phase coil assembly and a reverse-phase coil assembly. According to the electromagnetic ultrasonic transducer, an external bias magnetic field is automatically generated through excitation current with a special waveform when a pulsed magnetic field is excited in a to-be-detected ferromagnetic pipeline; and magnetostriction effects which are alternately distributed and generated by the normal-phase coil assembly and the reverse-phase coil assembly meet the matching relation of ultrasonic constructive interference, and therefore, electromagnetic ultrasonic longitudinal guided waves which are propagated in an axial direction are excited in the ferromagnetic pipeline. The invention further discloses an electromagnetic ultrasonic excitation device using the transducer and an electromagnetic ultrasonic receiving device using the transducer. According to the electromagnetic ultrasonic transducer, a direct-current coil andan alternating-current coil do not need to be arranged, and therefore, structural simplicity can be realized; with the corresponding excitation device and receiving device adopted, rigid permanent magnets are not needed to provide a bias magnetization field, and therefore, the size of the transducer is reduced.

Description

technical field [0001] The invention relates to the field of electromagnetic ultrasonic guided wave detection technology and equipment, in particular to an electromagnetic ultrasonic transducer applied to ferromagnetic pipelines, which can be used for nondestructive detection of defects in ferromagnetic pipelines such as iron pipes and steel pipes. Background technique [0002] With the rapid development of energy industries such as natural gas and oil, pipeline transportation has the advantages of high efficiency, low loss, and low cost, and has attracted more and more attention from the industrial field. These pipelines are basically ferromagnetic pipelines. However, the corrosion resistance of ferromagnetic pipelines is weak, and under the harsh working conditions in the pipeline, defects such as cracks and corrosion are prone to occur. If these defects cannot be checked and dealt with in time, it will further cause pipeline leakage and explosion, resulting in huge econom...

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Problems solved by technology

[0008] However, the electromagnetic ultrasonic transducers currently used for pipeline defect detection mainly have the following deficiencies: First, the electromagnetic ultrasonic transducers mostly use the Lorentz force effect for excitation, while the online pipelines are mostly ferromagnetic pipes, so the efficiency of ultrasonic excitation is not high. Second, the electromagnetic ultrasonic transducers all use rigid magnets to provide the bias magnetic field, and the probe is large in size, which is not suitable for the miniaturization and portability of the electromagnetic ultrasonic transducer for pipeline defect detection.

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