CN204302227U - A kind of array probe of ferromagnetism light-wall pipe circumference ac magnetization Magnetic Flux Leakage Inspecting - Google Patents

Abstract

The utility model belongs to the technical field of electromagnetic non-destructive detection of ferromagnetic thin-wall inner penetrating detection of nuclear power plant and other electromagnetic non-destructive detection of ferromagnetic thin pipe walls, and in particular relates to an array probe for circumferential AC magnetization magnetic flux leakage detection of ferromagnetic thin-wall pipes . It includes two rows of giant magnetoresistance sensors and excitation coils uniformly distributed along the circumference of the pipe; the giant magnetoresistance sensors and excitation coils in each row are arranged at intervals, and the giant magnetoresistance sensors and excitation coils in the two rows are arranged alternately. When performing pipeline detection, firstly activate the two adjacent excitation coils on the first row of coils, and then realize the sequential excitation of other excitation coils of this row of coils, and after the sequence has completed this single row of coils, activate the second row The two excitation coils close to the front row of coils realize sequential excitation of other excitation coils of this row of coils. The utility model can realize the detection of the axial defect of the small-diameter sample pipe.

Description

An Array Probe for Circumferential AC Magnetization Flux Leakage Detection of Ferromagnetic Thin-walled Tubes

technical field

The utility model belongs to the technical field of electromagnetic non-destructive detection of ferromagnetic thin-wall inner penetrating detection of nuclear power plant and other electromagnetic non-destructive detection of ferromagnetic thin pipe walls, and in particular relates to an array probe for circumferential AC magnetization magnetic flux leakage detection of ferromagnetic thin-wall pipes .

Background technique

The electromagnetic detection method of ferromagnetic tubes in nuclear power plants mainly uses far-field eddy current at this stage. The far-field eddy current has a certain sensitivity and resolution for the detection of defects, but due to the magnetic saturation method of the permanent magnet, its magnetization cannot be adjusted, which may lead to insufficient magnetization, so that the residual magnetic field of the ferromagnetic tube interferes with the detection signal , In addition, the far-field eddy current adopts more axial excitation, that is, the N-S poles of the permanent magnets are placed along the tube axis. This placement method is more sensitive to the detection of circumferential defects, but it is difficult to detect axial defects.

Magnetic flux leakage detection technology is an automatic detection technology derived from magnetic powder technology to detect the leakage magnetic field of ferromagnetic tubes. The method detects the leakage magnetic field caused by the defect by magnetizing the ferromagnetic tube, so as to achieve the qualitative and quantitative judgment of the defect. The detection method of the leakage field for the circumferential defect (axial magnetization) of the pipeline is similar to that of the far-field eddy current; however, for the detection of the axial defect (circumferential magnetization), the permanent magnet N-S pole is placed perpendicular to the pipe axis, and the The permanent magnet is rotated around the pipe axis to magnetize the entire pipe in the circumferential direction. Since the direction of the magnetic field is along the pipe wall, it is more sensitive to axial defects. There are many bends in the pipelines of nuclear power plants, the noise caused by mechanical rotation and the difficulty of control make it not optimal to use mechanical rotation.

Contents of the invention

The purpose of the utility model is to provide an array probe for circumferential AC magnetization magnetic flux leakage detection of ferromagnetic thin-walled tubes, so as to realize the detection of axial defects of small-diameter sample tubes.

In order to achieve the above object, the technical scheme adopted by the utility model is:

An array probe for circumferential AC magnetization flux leakage detection of ferromagnetic thin-walled pipes, including two rows of giant magnetoresistive sensors and excitation coils uniformly distributed along the circumference of the pipe; the giant magnetoresistance sensors and excitation coils in each row are arranged at intervals, The giant magnetoresistive sensors and excitation coils are arranged alternately.

The excitation coil is a shaft-wound coil.

When performing pipeline detection, firstly activate the two adjacent excitation coils on the first row of coils, and then realize the sequential excitation of other excitation coils of this row of coils, and after the sequence has completed this single row of coils, activate the second row The two excitation coils close to the front row of coils realize sequential excitation of other excitation coils of this row of coils.

The beneficial effects obtained by the utility model are:

The utility model realizes the circumferential magnetization of the pipeline by means of electronic rotation instead of mechanical rotation, and uses a giant magnetoresistive device as a detection sensor to realize the detection of axial defects by the probe, which reduces the influence of the mechanical rotation of the probe on the defect detection sensitivity. The anti-interference ability of the probe is enhanced. Due to the use of coil magnetization and power limitation, the probe with this structure is suitable for built-in detection of thin-walled and small-diameter thin-walled tubes.

(1) By using the electromagnetic coil to excite the magnetic field to magnetize the ferromagnetic tube, the original permanent magnet is used as the magnetization source, and the local magnetization method is used to improve the uniformity of the magnetic field in the area. In addition, the magnetic field strength can be adjusted by the electromagnet , so the corresponding leakage magnetic field intensity will also change accordingly, which has more advantages than permanent magnets;

(2) The circumferential magnetization method of electronic rotation is adopted, which reduces the noise interference and control difficulty caused by mechanical rotation, and at the same time, the magnetization speed is faster than that of mechanical rotation;

(3) For the circumferential excitation unit, the staggered arrangement of coils and sensors on a single row ensures the detection of the leakage magnetic field of defects, while the staggered arrangement of two rows realizes the coverage of the magnetization field of the entire circumferential pipe wall and Detection of axial defects on the entire circumferential pipe wall;

(4) The coil will heat up during the long-term detection process. If the coil is used for detection, the signal-to-noise ratio of the detected signal will be seriously disturbed. The giant magnetoresistive sensor has a good effect of suppressing temperature drift, which can ensure good defect detection SNR.

Description of drawings

Fig. 1 is the array probe structural diagram I of the utility model ferromagnetic thin-walled tube circumferential alternating current magnetization flux leakage detection;

Fig. 2 is the array probe structure diagram II of the utility model ferromagnetic thin-walled tube circumferential AC magnetization flux leakage detection;

Fig. 3 is a schematic diagram of the distribution characteristics of the circumferential excitation field of the magnetic flux leakage detection probe;

Fig. 4 is a schematic diagram of the magnetic field distribution characteristics of A-A-the first row of coils;

Fig. 5 is a schematic diagram of B-B-second row coil magnetic field distribution characteristics;

In the figure: 1. giant magnetoresistive sensor; 2. excitation coil.

Detailed ways

The utility model will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

As shown in Fig. 1-Fig. 5, the array probes for the circumferential AC magnetization magnetic flux leakage detection of ferromagnetic thin-walled tubes described in the utility model include two rows of giant magnetoresistive sensors 1 and excitation coils 2 uniformly distributed along the circumferential direction of the tube; The giant magnetoresistance sensors 1 and the excitation coils 2 are arranged at intervals, and the giant magnetoresistance sensors 1 and the excitation coils 2 in the two rows are arranged alternately. The exciting coil 2 is a shaft-wound coil.

When detecting the pipeline, firstly excite the two adjacent excitation coils 2 on the first row of coils, and then realize the sequential excitation of other excitation coils 2 of this row of coils. After the sequence has completed the single row of coils (clockwise excitation or anticlockwise excitation), excite the two excitation coils 2 of the second row of coils that are close to the front row (clockwise excitation or counterclockwise excitation is acceptable), and then realize the sequential excitation of other excitation coils 2 of this row of coils . During the detection process, the timing excitation parameters of the circumferential magnetization can also be adjusted in combination with the sampling rate, the moving speed of the probe along the axis, and the position feedback of the encoder.

Claims (3)

1. an array probe for ferromagnetism light-wall pipe circumference ac magnetization Magnetic Flux Leakage Inspecting, is characterized in that: comprise along two uniform row's giant magneto-resistance sensor (1) and magnet exciting coils (2) of tubing circumference; Often in row, giant magneto-resistance sensor (1) and magnet exciting coil (2) interval are arranged, the giant magneto-resistance sensor (1) in two rows and magnet exciting coil (2) interlaced arrangement.

2. the array probe of ferromagnetism light-wall pipe circumference ac magnetization Magnetic Flux Leakage Inspecting according to claim 1, is characterized in that: described magnet exciting coil (2) is for axle is around formula coil.

3. the array probe of ferromagnetism light-wall pipe circumference ac magnetization Magnetic Flux Leakage Inspecting according to claim 1, it is characterized in that: when carrying out the detection of pipeline, first two magnet exciting coils (2) adjacent on first row coil are excited, realize exciting successively of other magnet exciting coil (2) of this winding displacement circle again, after sequential has covered this single-row winding, excite two magnet exciting coils (2) close with front row of second row coil, then realize the exciting successively of other magnet exciting coil (2) of this winding displacement circle.