KR102265354B1 - annular array eddy currentprobe non-destructive inspection device equipped with magnetic lenses - Google Patents

Abstract

The present invention relates to a ring-shaped arrangement of an eddy-current probe nondestructive inspection apparatus equipped with magnetic lenses, capable of detecting defects in axial and circumferential directions and quantitatively evaluating the same by concentrating a magnetic flux through coils embedded and arranged in a case of a ferromagnetic body material having a trapezoidal cross section, and then, measuring a phase difference with impedance caused by a defect passing therethrough. In accordance with the present invention, the ring-shaped arrangement of an eddy-current probe nondestructive inspection apparatus equipped with magnetic lenses includes unit probe modules combined with each other to form a donut-shaped apparatus body. The unit probe modules include: a case tapered with a width becoming gradually smaller throughout an extension from an upper side to a lower side, and having a predetermined internal space; and an embedded coil installed in the case, and receiving an alternating current to form an AC magnetic field, thereby forming an induced current to an inspection subject.

Description

Annular array eddy currentprobe non-destructive inspection device equipped with magnetic lenses

The present invention relates to an annular array eddy current probe non-destructive testing device having a magnetic lens, and more particularly, by embedding a coil in a ferromagnetic material case having a trapezoidal cross section and arranging the coil to focus the magnetic flux, and to prevent defects passing through it It relates to an annular array eddy current probe non-destructive testing apparatus having a magnetic lens that can detect and quantitatively evaluate defects in the axial and circumferential directions by measuring the impedance and phase difference of the

Eddy current non-destructive testing is a method of detecting defects inherent in the object to be measured using electromagnetic phenomena. When an alternating current is applied to a coil adjacent to the object to be measured, an induced current is generated in the object to be measured. If a defect exists in the path of the induced current, the flow of the induced current is distorted, and accordingly, the distribution of the time-varying magnetic flux density around the defect is changed. If this is measured by a coil, the presence, location and size of defects can be inspected. Such eddy current non-destructive testing is being used throughout the industry to check the soundness of metal structures.

For example, the heat exchanger performs functions such as heating, cooling, and condensation by transferring the heat of the fluid through the heat transfer surface of the heat transfer tube. Heat exchanger tubes that have been used for a long time under high temperature, high pressure, vibration, and hydrochemical environments may be damaged by corrosion, corrosion, erosion, pitting, abrasion, thinning, fatigue cracking, SCC, and IASCC. If the original function of the heat exchanger cannot be performed due to such damage, the normal operation of the power plant may be disturbed. Therefore, a non-destructive inspection to check the integrity of the heat exchanger tube is periodically performed during the planned preventive maintenance period of the power plant.

The bobbin-type eddy current non-destructive inspection to check the integrity of the heat exchanger tube is periodically performed during the planned preventive maintenance period of the power plant. Among them, an annular array transducer has been developed that can be used for defect determination and quantitative evaluation at a faster speed by arranging active coil sensors in an annular shape along the inner wall of a small-diameter heat pipe and scanning in the axial direction. However, in the case of the active coil sensor, mutual interference occurs when all the sensors arranged in an annular shape are simultaneously driven. As a solution to this problem, the distance between the sensors should be widened or the intersection drive should be driven while maintaining a distance between the sensors and the sensors to avoid interference. In addition, a difference in eddy current occurs at the center and edge of the coil, which degrades the 360 degree coverage performance. And, the defect detection performance is different depending on the direction of the cracking defect.

The phenomenon that the defect detection performance differs depending on the direction of such cracking defects does not occur only in non-destructive testing of small diameter tubes such as heat exchanger tubes. That is, even when the shape of the test piece is flat or curved, there is a limit in that it is difficult to inspect cracking defects in the direction perpendicular to the arrangement direction of the sensors.

Korean Patent Publication No. 10-2019-0010293 (2019.01.30)

The present invention has been devised to solve the above-described problems, and the magnetic flux is focused on a ferromagnetic case having a trapezoidal cross section surrounding the coil sensor, and the impedance and phase difference of the embedded coil change when a defect passes through a part of the case An object of the present invention is to provide an annular array eddy current probe non-destructive testing apparatus having a magnetic lens capable of detecting defects at high speed by measuring and quantitatively evaluating them.

An annular array eddy current probe non-destructive testing apparatus having a magnetic lens according to the present invention includes a unit probe module that can be coupled to each other to form a donut-shaped device body, wherein the unit probe module has a width as it extends downward from an upper surface. A case is tapered to become smaller and has a predetermined internal space, and a buried coil installed inside the case and configured to generate an induced current in an object to be inspected by applying an alternating current to form an alternating magnetic field.

The case is formed in a parallelogram shape with an upper surface and a lower surface, and the buried coil is embedded in the case, and as it extends from the upper part to the lower part of the case, the outer diameter is tapered to correspond to the width of the case. desirable.

The case may be formed of a ferromagnetic material to enable magnetic shielding of other adjacent unit probe modules, and a metal coating may be formed on a contact surface in contact with the case of an adjacent unit probe module.

According to the annular array eddy current probe non-destructive inspection apparatus having a magnetic lens according to an embodiment of the present invention, the defect detection performance is improved by improving the 360 degree coverage performance, the speed is improved by the simultaneous driving by magnetic shielding, and the magnetic flux focusing Since the sensor width in the axial direction is narrow even in the state of energy concentration efficiency and arrangement, it is effective to inspect the curved pipe part.

1 is a perspective view of an embodiment of an annular array eddy current probe non-destructive testing apparatus having a magnetic lens according to the present invention;
2 is a perspective view showing an excerpt of a unit probe module from the annular array eddy current probe non-destructive testing apparatus having a magnetic lens of FIG. 1;
3 is a circuit diagram of an embodiment of a driving circuit capable of simultaneously driving a magnetic sensor;
4 is a circuit diagram of a driving circuit capable of simultaneously measuring unit probe modules by single or parallel driving;
5 is a circuit diagram of a driving circuit capable of driving unit probe modules in parallel and performing signal input alone or in parallel;
6 is a circuit diagram of a driving circuit that can measure single or simultaneously by selecting a specific sensor while simultaneously driving single or several by selecting a coil;
7 is a circuit diagram of a driving circuit for outputting data comparing the output of a specific sensor with a reference coil while simultaneously driving a single or multiple sensors by selecting a sensor;
8 is a circuit diagram of a driving circuit for selecting a sensor and driving a single or multiple sensors at the same time to acquire a differential signal between specific sensors;
9 is a circuit diagram of a driving circuit capable of inputting an alternating current by selecting a specific coil and acquiring an output signal from another sensor.

Hereinafter, an annular array eddy current probe non-destructive testing apparatus having a magnetic lens according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. Since the present invention can have various changes and can have various forms, specific embodiments are illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to the specific disclosed form, it should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention. In describing each figure, like reference numerals have been used for like elements. With respect to the accompanying drawings, the dimensions of the structures are enlarged than in reality for clarity of the present invention.

Terms such as first, second, etc. may be used to describe various elements, but the elements should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present application, terms such as “comprise” or “have” are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, but one or more other features It is to be understood that it does not preclude the possibility of the presence or addition of numbers, steps, operations, components, parts, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related art, and should not be interpreted in an ideal or excessively formal meaning unless explicitly defined in the present application. does not

1 to 2 show an embodiment of an annular array eddy current probe non-destructive testing apparatus 10 having a magnetic lens according to the present invention.

Referring to the drawings, the annular array eddy current probe non-destructive testing apparatus 10 having a magnetic lens includes a unit probe module 100 that is assembled to form a donut shape.

The unit probe module 100 includes a case 110 and a buried coil 120 .

The case 110 is a member of a ferromagnetic material having a predetermined inner space so that the buried coil 120 can be mounted on the inner periphery, and is tapered to become narrower as it extends from the upper part to the lower part.

When the case 110 is combined with another adjacent unit probe module 100, the lower surface forms the inner peripheral surface of the donut-shaped inspection device, and the upper surface forms the outer peripheral surface of the inspection device.

The upper and lower surfaces of the case 110 are formed in a parallelogram shape. Therefore, when the direction of the defect formed in the heat transfer tube or the test piece is in the axial direction or the circumferential direction, the defect must pass through the case 110, so that the impedance and phase difference due to the defect occur.

In addition, the case 110 is formed of a ferromagnetic material to allow magnetic shielding of the buried coil 120 to be embedded. In particular, the case 110 of other adjacent unit probe modules 100 to increase the magnetic shielding performance. It is preferable to apply a separate metal coating to the side portion that comes into contact with the .

The embedded coil 120 is embedded in the case 110 and is wound in a tapered shape to form a shape parallel to the side surface of the case 110 . That is, the coil is wound on the basis of the central axis extending in the radial direction from the central position of the inspection device, which is in the shape of a donut, and the outer diameter of the coil becomes smaller and smaller corresponding to the width of the case 110 as it extends downward from the top. do.

The inclination of the outer peripheral surface of the buried coil 120 is preferably formed to correspond to the inclination of the side surface of the case 110 .

When an alternating current is applied to the buried coil 120 in a state in which the buried coil 120 is embedded in the case 110 in this way, magnetic flux is concentrated in the case 110 and the heat pipe adjacent to the surface of the case 110 . Alternatively, the induced current is concentrated and applied to the test piece. And when the induced current is distorted by a defect, the impedance and the phase difference of the buried coil 120 change, and by measuring this, the presence, size, and location of the defect can be evaluated.

3 is an embodiment of a driving circuit capable of simultaneously driving the arrayed magnetic sensors. Since the unit probe module of the present invention can be magnetically shielded, the coil and the sensor can be simultaneously driven in parallel.

Reference numeral 200 denoted in the drawing denotes an AC power applying unit for applying AC power, 300 denotes a coil, and 400 denotes a sensor.

4 is another embodiment of a driving circuit capable of simultaneously measuring the unit probe module 100 by single or parallel driving.

In the driving circuit of this embodiment, the unit probe module can be driven individually or in parallel, and parallel signal input is possible.

In another embodiment of the driving circuit shown in FIG. 5, the unit probe modules may be driven in parallel, and signal input may be performed alone or in parallel. In other words, it is possible to measure single or simultaneous measurements by selecting sensors while simultaneously driving the coils.

The driving circuit may be formed as shown in FIG. 6 . In the case of the driving circuit shown in FIG. 6 , a single or several coils are selected to drive a single or several simultaneously, and a specific sensor can be selected to measure single or simultaneously.

7 is a driving circuit for outputting data comparing an output of a specific sensor with a reference coil while simultaneously driving a single or multiple sensors by selecting the sensor.

8 is a driving circuit for selecting a sensor and simultaneously driving a single or several sensors to acquire a differential signal between specific sensors.

9 shows that an AC current may be input by selecting a specific coil, and an output signal from another sensor may be acquired. That is, it is a driving circuit capable of separating the excitation coil and the pickup coil.

The annular array eddy current probe non-destructive testing device 10 having a magnetic lens of the present invention described above is a unit probe module including a buried coil 120 embedded in a magnetic shielding case 110 to be installed in a donut shape. Since defects can be measured in multiple probes by combining them, the possibility and accuracy of defect determination can be increased, and the unit probe module 100 can be driven in various forms through various circuit configurations.

The description of the presented embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the scope of the invention. Thus, the present invention is not to be limited to the embodiments presented herein, but is to be construed in the widest scope consistent with the principles and novel features presented herein.

10: annular array eddy current probe non-destructive testing device with magnetic lens
100: unit probe module
110: case 120: buried coil
200: AC power supply
300: coil
400: sensor

Claims (4)

It includes a unit probe module that can be combined with each other to form a donut-shaped device body,
The unit probe module is tapered so that the width gradually decreases as it extends downward from the upper surface, the case having a predetermined internal space;
and a buried coil installed inside the case, to which an alternating current is applied to form an alternating magnetic field to form an induced current in the object to be inspected;
The case is formed of a ferromagnetic material to enable magnetic shielding of other adjacent unit probe modules,
A metal coating is formed on the contact surface in contact with the case of the adjacent unit probe module.
Annular array eddy current probe non-destructive testing device with magnetic lens.
The method of claim 1,
The case is characterized in that the upper and lower surfaces are formed in a parallelogram shape
Annular array eddy current probe non-destructive testing device with magnetic lens.
The method of claim 1 .
The buried coil is
It is embedded in the case, characterized in that as it extends from the upper part to the lower part of the case, the outer diameter is tapered to correspond to the width of the case.
Annular array eddy current probe non-destructive testing device with magnetic lens.
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