An adjustable magnetostrictive guided wave sensor

Abstract

The invention provides an adjustable magnetostrictive waveguide sensor, which comprises four magnetic circuits and a flexible printed sensing coil, wherein the four magnetic circuits are uniformly distributed in the circumferential direction of a heated surface tube and form a closed loop circuit together with the heated surface tube; the flexible printed sensing coil is wound on the heated surface tube at least one time; each magnetic circuit comprises a yoke, permanent magnets and saddles; the permanent magnets are arranged above the saddles; the yokes are arranged above the permanent magnets; the saddles are of arc structures, and the length of the surface, in contact with the corresponding permanent magnet, of each saddle is twice the width of each of the permanent magnets and the yokes; the width of the flexible printed sensing coil is a half of a wavelength exciting a longitudinal L (0, 2) mode under excitation frequency, and can be adjusted within the magnetic circuits along the axial direction of the heated surface tube. According to the sensor, reflection echo signals with higher excitation signal energy and simpler wave packet structures can be received by changing the position of the flexible printed sensing coil in the magnetic circuits of the heated surface tube, and a sensor structure-position relationship suitable for the heated surface tube is determined, so that the sensor can be used for detecting the heated surface tube from a long distance in a non-contact way, detection signals are simple, clear and convenient to analyze, and the detection cost is further lowered.

Description

technical field [0001] The invention relates to the field of electric power detection, in particular to the field of detection of heating surface tubes of power stations, specifically an adjustable magnetostrictive guided wave sensor for detecting heating surface tubes. Background technique [0002] Power stations need to use a large number of heating surface tubes. These pipelines work under high temperature and high pressure, and are prone to various crack defects. The tube burst caused by them will seriously affect the safe operation of the pipeline. The detection of the heating surface tube mainly adopts point-by-point scanning methods, such as electromagnetic method, conventional ultrasonic method and ray detection method, etc. These methods have high requirements on the surface condition of the heating surface tube and require special grinding, resulting in low detection efficiency. Time-consuming and labor-intensive, it is difficult to carry out mass inspection. At t...

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Problems solved by technology

[0002] The power station needs to use a large number of heating surface tubes. These pipelines work under high temperature and high pressure, and are prone to various crack defects. The tube burst caused by them will seriously affect the safe operation of the pipeline.

The detection of the heating surface tube mainly adopts point-by-point scanning methods, such as electromagnetic method, conventional ultrasonic method and ray detection method, etc. These methods have high requirements on the surface condition of the heating surface tube and require special grinding, resulting in low detection efficiency. Time-consuming and labor-intensive, it is difficult to conduct large-scale inspections

At the same time, the space distribution of the heating surface pipe is compact and the length is long. Many parts of the pipe are difficult to access and cannot be inspected. It is difficult to comprehensively and effectively inspect with ordinary inspection methods.

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