KR20120066892A - Apparatus of magnetic inspection for non-destructive test and method of non-destructive test by the same - Google Patents

Abstract

The present invention provides a self-detection apparatus and non-destructive testing method for non-destructive testing that can secure the reproducibility by performing the entire non-destructive inspection regardless of the pipe form and perform the inspection method with an automated system. The apparatus and method includes a control unit arranged between a pair of flaw detectors for imparting a magnetic field to control the magnetic flaw detector using a voltage change recognized by a sensor part for converting a change in the magnetic field into a voltage change. Perform the test.

Description

Apparatus of magnetic inspection for non-destructive test and method of non-destructive test by the same}

The present invention relates to a non-destructive inspection device and an inspection method, and more particularly, to a magnetic inspection device for non-destructive inspection for detecting damage, such as corrosion or cracking of the pipe by a change in the magnetic field, and an inspection method therefor.

Piping plays an important role in industrial installations such as petrochemical plants. In other words, the pipe is a movement path of the composition in the form of gas, liquid for the additional process or atmosphere composition produced in each process. However, various chemical components and process conditions used here are damaged by various causes that can occur in the pipe, in particular, the carbon steel that is most used as a material of the pipe is caused by corrosion or cracking due to the above causes. Accordingly, users periodically check the pipe for damage by using various methods.

Among the non-destructive tests for the condition diagnosis of carbon steel equipment, the most widely used method is magnetic particle test. If the material is a magnetic body such as carbon steel, the magnetic particle test method can be easily applied, and the inspection results can be visually observed. Specifically, the magnetic particle test method is to spray the magnetic powder on the pipe to be inspected to observe the change of the magnetic powder by the magnetic field to find out whether the pipe is damaged.

However, the magnetic particle test is performed by hand, the result of the test is temporary, and the degree of damage to the pipe cannot be quantitatively expressed. Accordingly, it is difficult to apply this to a plumbing facility installed in a complicated form, it is difficult to secure reproducibility, and there is a difficulty in automating an inspection method. In addition, the magnetic particle test method is troublesome to remove the magnetic powder sprayed on the pipe after the inspection.

The problem to be solved by the present invention is to provide a self-detection apparatus for non-destructive inspection that can secure the reproducibility by performing the entire non-destructive inspection irrespective of the form of the pipe and can perform the inspection method by an automated system. In addition, another object of the present invention is to provide a method for performing a non-destructive inspection by the magnetic examination device.

The magnetic flaw detector for non-destructive inspection of the present invention for solving the above problems includes a pair of flaw detectors for imparting a magnetic field, and a sensor unit disposed between the flaw detectors and converting a change in the magnetic field into a voltage change. In addition, the yoke for mounting the flaw detection unit and the sensor unit inside, a drive unit for moving the yoke along the pipe and a control unit for controlling the magnetic flaw detection apparatus using the voltage change recognized by the sensor unit.

In the magnetic flaw detector according to the present invention, the flaw detector may have a permanent magnet or an induction magnet. In addition, the sensor unit may use a hall sensor arranged in an array form. Furthermore, the controller may output data of the voltage change converted by the sensor unit in the form of an image.

In the preferred device of the present invention, the yoke may be formed with a groove or groove in which the flaw detector and the sensor unit may be mounted. At this time, the width between the center of the flaw detection portion may be determined by the diameter of the pipe, the material of the pipe, the thickness of the pipe wall and the coercive force of the magnet, the width of the sensor portion is the diameter of the pipe, the material of the pipe, the pipe wall It can be determined by the thickness and the coercive force of the magnet.

In the non-destructive inspection method by magnetic flaw detection for solving the other problem of the present invention, first, the ground state, the width between the center of the flaw detection part and the width of the sensor part are determined according to the pipe. Thereafter, a magnetic field is formed in the pipe by the flaw detector. Due to the magnetic field of the flaw detector, a change in the magnetic field generated along the pipe is converted into a voltage change by the sensor unit. The voltage change is analyzed by the controller.

In the inspection method of the present invention, the controller may output the voltage change in the form of an image, and the voltage change may be output in the form of an image according to a channel.

According to the magnetic flaw detection apparatus for the non-destructive inspection and the inspection method thereof of the present invention, by changing the change in the magnetic field according to the pipe into a voltage change by analyzing the voltage change using a sensor unit for detecting the damage to the pipe, Nondestructive testing can be performed to automate the entire non-destructive testing, ensuring reproducibility, and to perform the inspection method with an automated system.

1A is a perspective view showing a magnetic flaw detector according to the present invention.
FIG. 1B is a photograph showing the sensor part of FIG. 1A.
2 is a cross-sectional view for explaining a magnetic flaw detection method according to the present invention.
Figure 2b is a cross-sectional view showing in detail the self-detection method according to the present invention to the periphery of the yoke when there is damage to the pipe.
Figure 3a is a graph showing the result of the magnetic inspection according to the present invention as a voltage change according to the position of the pipe.
FIG. 3B is an image representing a portion where pipe damage occurs in FIG. 3A according to a channel.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The embodiments described below may be modified in various forms, and the scope of the present invention is not limited to the embodiments described below. Embodiments of the present invention are provided to more fully explain the present invention to those skilled in the art.

Embodiment of the present invention by using a sensor that detects the damage of the pipe by converting the change of the magnetic field into a voltage change, to secure the reproducibility by automating the entire non-destructive inspection irrespective of the shape of the pipe and the inspection method to an automated system We present a magnetic flaw detector for nondestructive testing that can be performed. A magnetic flaw detection apparatus for controlling the change of the voltage due to the change of the magnetic flux and automating the inspection by controlling the same will be described, and the inspection method by the apparatus will be described.

1A is a perspective view showing a magnetic flaw detector according to an embodiment of the present invention. FIG. 1B is a photograph showing the sensor part of FIG. 1A.

Referring to FIGS. 1A and 1B, a pair of flaw detectors 40 for providing a magnetic field and a sensor part 50 disposed at regular intervals between the flaw detectors 40 to convert a change in the magnetic field into a voltage change are provided. ), The yoke 10 for mounting the flaw detector 40 and the sensor unit 50 to the inside, the driving unit 20 for moving the yoke 10 along the pipe, and the voltages detected by the sensor unit 50. And a controller 60 for controlling the magnetic flaw detector using the change. The pair of flaw detectors 40 are equipped with a magnet 42 for generating a magnetic field, thereby forming magnetic fields therebetween. At this time, the magnet 42 may be a permanent magnet, or may be an induction magnet wound coil.

The sensor unit 50 is a device that detects a change in a magnetic field, that is, a magnetic flux change according to the pipe state by the flaw detector 40, and converts it into a voltage change. The sensor unit 50 may be formed of a coil for detecting a hall sensor or an induction magnetic field, and the hall sensor 52 is preferable. The Hall sensor 52 is a transistor that senses a change in the magnetic field and is a device well known to be used to measure the intensity or distribution of the magnetic field. In the embodiment of the present invention, rather than using one hall sensor 52, a plurality of hall sensors arranged in an array form can be arranged to secure a wider area for inspection.

The yoke 10 mounts a pair of the flaw detection part 40 and the sensor part 50 arrange | positioned between the flaw detection part 40 inside, The part which contacts a piping is open, and the remainder is blocked. It has a structure. As shown, the yoke 10 is a "c" shape of the flaw detection part 40 and the sensor part 50 is fixed to the upper wall, the part in contact with the pipe is open, both sides of the upper wall It is blocked by the side wall. In addition, the inner surface of the upper wall of the yoke 10 is provided with a mounting groove 12 on which the flaw detector 40 and the sensor unit 50 can be mounted. If necessary, the mounting groove 12 may have a groove shape instead of a groove shape to more precisely adjust the position of the flaw detector 40 and the sensor part 50.

The driving unit 20 is installed outside the side wall of the yoke 10, and the driving force can be obtained by using an electric motor. A moving unit 30 is provided between the driving unit 20 and the side wall of the yoke 10 to move by the driving force of the driving unit 20. The moving part 30 is equipped with the wheels 32 and moves along the pipe by the rotation of the wheels 32. At the end of the wheel 32, fine concavities and convexities may be formed or a rubber material may be formed so that the wheel 32 is easily adhered to the pipe.

The controller 60 collects data of the voltage change converted by the sensor unit 50 through the signal line 62 and analyzes the data, and controls the movement of the moving unit 30. The control unit 60 may be integrally installed on the yoke 10, or may be installed separately from the yoke 10. The controller 60 may output the voltage change to the screen, preferably -10V to + 10V, and the voltage change may be output in an image form to easily determine whether the pipe is damaged by the output image. have.

2 is a cross-sectional view for explaining a magnetic examination method according to an embodiment of the present invention. Figure 2b is a cross-sectional view showing in detail the self-detection method according to the embodiment of the present invention when there is damage to the pipe to the periphery of the yoke. In this case, the magnetic examination apparatus will be described with reference to FIGS. 1A and 1B.

According to FIG. 2A, specifically, a magnetic force line is generated between the magnets 42 mounted on the pair of flaw detectors 40 to form a route through which the magnetic force line passes through the pipe 70. It moves along the pipe 70 by the drive part 20, and examines whether the pipe 70 has damage, such as corrosion or a crack, through the change of the magnetic field by a magnetic force line. The pipe 70 may be all made of a material through which the magnetic force lines pass within the scope of the present invention, but a ferromagnetic material such as iron or nickel is more preferable.

As is well known, when the distance between the lines of magnetic force passing through the pipe 70 is narrow, the lines of magnetic force are dense and the magnetic flux density is large, so the strength of the magnetic field is large. If the pipe 70 is not damaged, the cross-sectional area of the pipe through which the magnetic force lines pass is constant, so that the voltage change does not appear in the controller 60. The state in which the voltage change does not appear is called a base state. The ground state is set in advance according to the material, shape, and the like of the pipe to be inspected, and is stored in the controller 60 in the form of a look-up table.

According to FIG. 2B, when damage due to corrosion or cracking occurs in the pipe 70, the damaged portion has a change in cross-sectional area, and thus a change in the distance between the lines of magnetic force, that is, the strength of the magnetic field. For example, due to damage of the pipe 70, if the cross-sectional area through which the lines of magnetic force pass, that is, the thickness Δt of the pipe, decreases, the distance between the lines of magnetic force becomes narrow and the magnetic flux density increases, thereby increasing the strength of the magnetic field. Such a change in the magnetic field is recognized as a voltage change by the sensor unit 50 so that the voltage change is expressed by the controller 60.

In the figure, the width W1 connecting the centers of the pair of flaw detectors 40 is determined according to the pipe 70 which is the inspected object. That is, the width W1 is previously determined according to the diameter of the pipe 70, the material of the pipe, the thickness of the wall of the pipe 70, the coercive force of the magnet 42, and the like. Specifically, before inspecting the pipe 70 to be inspected, a plurality of inspections are performed on a sample of the undamaged pipe 70 to determine the width W1, and the control unit 60 determines the width W1. Can be stored in the form of a lookup table. In this case, the width W1 can be adjusted by fitting the flaw detector 40 to the mounting groove 12 formed in the yoke 10.

The width W2 of the sensor portion 50 represents the area of the pipe 70 to be inspected by the magnetic flaw detector of the present invention. If the width W2 is wide, the area of the pipe 70 to be inspected is widened. If the width W2 is narrow, the area of the pipe 70 to be inspected is narrowed. The width W2 is previously determined according to the diameter of the pipe 70, the material of the pipe, the thickness of the wall of the pipe 70, the coercive force of the magnet 42, and the like. Specifically, before inspecting the pipe 70 to be inspected, a plurality of inspections are performed on a sample of the undamaged pipe 70 to determine the width W2, and the control unit 60 determines the width W2. Can be stored in the form of a lookup table. When the width W2 is widened, the number of hall sensors is designed to increase in the case of the hall sensor array forming the sensor unit 50.

As described above, according to the magnetic flaw detector according to the present invention, information such as ground state, width W1 and width W2 is stored and used in the controller 60 according to the state of the pipe 70 to be inspected. By reproducing the inspection of the pipe 70 can be carried out a more accurate inspection. In addition, by collecting information about the various types of pipe 70 can be obtained inspection conditions optimized for various environments.

Figure 3a is a graph showing the results of the self-detection according to the embodiment of the present invention as a voltage change according to the position of the pipe, Figure 3b is a representation of the damage portion of the pipe in FIG. Here, the pipe position is a place where the inspection starts in the ground state as the origin and is the distance in the direction in which the magnetic flaw detector moves according to a predetermined scale. In this case, the scale may be set differently according to the pipe described above.

As shown in FIG. 3A, the magnetic flaw detector starting from the origin is recorded in a ground state without damage to the pipes up to region a (0 to 150) of the pipe, as shown in FIG. 3A, and in the region b (after 150) of the pipe, It was found that the voltage change (ΔV) was larger than the ground state due to the damage. Of course, in the region a, the voltage change is slightly higher than the ground state, but it can be interpreted that the magnetic field is overlapped.

In order to clarify the damage state of the pipe, after forming a plurality of magnetic flaw detection channels, the voltage change was imaged and examined as shown in Figure 3b. The magnetic flaw detection channel may be implemented by repeatedly inspecting a plurality of devices described with reference to FIG. 1A, or by using a plurality of origins in a direction perpendicular to the moving direction of FIG. 2A. This is called a channel number for convenience. In the index of the figure, the voltage change is about 2.80 to 2.96, the intensity of which is represented by the shade of pink, which is a red color system, and the value of about 2.96 to 3.10 is the intensity of which is represented by the shade of green, which is a blue color system. It was.

In terms of the intensity of the shade, the change in voltage was approximately between 2.80 and 2.88 in the positions 150-310 of the pipe, approximately 2.88-2.96 in the 310-450, and 2.96-3.10 in the 450-600. Indicated. In particular, it was found that the greatest voltage change was found at the pipe positions 450 to 600 and channels 2 to 3. In other words, the most severe damage in the pipe position 450 ~ 600, channels 2 ~ 3, it was confirmed that the damage occurred around the center.

Combining Figs. 3A and 3B, the magnetic flaw detection apparatus of the present invention was able to pinpoint the damaged position of the pipe, and also it was possible to quantitatively confirm the degree of damage. Therefore, if the ground state is set and self-detection is performed along the pipe, the non-destructive test can be performed by automating the entire non-destructive test regardless of the shape of the pipe to secure reproducibility and perform the inspection method by an automated system. Can be.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but many variations and modifications may be made without departing from the scope of the present invention. It is possible.

10; Yoke 12; Mounting groove
20; A driver 30; Moving parts
32; Wheel 40; Flaw
42; Magnet 50; The sensor unit
52; Hall sensor 60; Control

Claims (11)

A pair of flaw detectors for imparting a magnetic field;
A sensor unit disposed between the flaw detectors and converting a change in a magnetic field into a voltage change;
Yoke for mounting the flaw detection unit and the sensor unit inside;
A driving unit for moving the yoke along a pipe; And
And a control unit for controlling the magnetic flaw detector using the voltage change recognized by the sensor unit. The magnetic flaw detector for non-destructive inspection according to claim 1, wherein a permanent magnet is attached to the flaw detector. The magnetic flaw detector for non-destructive inspection according to claim 1, wherein an induction magnet is attached to the flaw detector. The magnetic sensing device of claim 1, wherein the sensor unit uses hall sensors arranged in an array. The magnetic sensing device of claim 1, wherein the control unit outputs data of the voltage change converted by the sensor unit in the form of an image. According to claim 1, The yoke is a magnetic flaw detection apparatus for a non-destructive inspection, characterized in that the grooves or grooves in which the flaw detection unit and the sensor unit can be mounted. The magnetic flaw detector according to claim 1, wherein the width between the centers of the flaw detectors is determined by the diameter of the pipe, the material of the pipe, the thickness of the pipe wall, and the coercive force of the magnet. The magnetic flaw detector according to claim 1, wherein the width of the sensor part is determined by the diameter of the pipe, the material of the pipe, the thickness of the pipe wall, and the coercive force of the magnet. Determining a ground state, a width between the center of the flaw detection section, and a width of the sensor section according to the piping;
Forming a magnetic field in the pipe by the flaw detector;
Converting a change in the magnetic field generated by the pipe due to the magnetic field of the flaw detector into a voltage change by the sensor unit; And
Non-destructive inspection method by magnetic inspection for analyzing the voltage change by a control unit. 10. The method of claim 9, wherein the control unit outputs the voltage change in the form of an image. The method of claim 10, wherein the voltage change is output in the form of an image according to a channel.

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