WO2018128225A1

WO2018128225A1 - Eddy current array probe having an insulted transceiver unit and eddy current examination method using same

Info

Publication number: WO2018128225A1
Application number: PCT/KR2017/005275
Authority: WO
Inventors: 이태훈; 조찬희; 지동현; 유현주; 김인철
Original assignee: 한국수력원자력 주식회사
Priority date: 2017-01-03
Filing date: 2017-05-22
Publication date: 2018-07-12
Also published as: KR101941354B1; CN110140049A; KR20180079989A

Abstract

The present invention provides an eddy current array probe having an insulated transceiver unit and an eddy current examination method using the same. The eddy current array probe may comprise: a body; a plurality of magnetic excitation elements arranged in one row along the periphery of the body; and a plurality of magnetic field detecting elements arranged in the one row at positions spaced apart a pre-set interval from the magnetic excitation coil.

Description

Array eddy current probe with insulated transceiver and eddy current inspection method using same

Embodiments of the present invention relate to an arrayed eddy current probe insulated from a transceiver for detecting circumferential cracks and residual material present on the outer surface of a heat exchanger conductive tube and an eddy current inspection method using the same.

Tubes of heat exchangers used in nuclear power plants are made of fine tubes with good heat transfer rate, corrosion resistance and thinness to improve heat exchange performance. These customs maintain pressure boundaries and are exposed to harsh environments, causing various types of defects such as cracks caused by high and high pressures, abrasion between pipes and pipe supports, and dents. Therefore, it is necessary to periodically perform nondestructive testing for the soundness diagnosis of the heat exchanger tube. Since most heat exchanger tubes are made of nonmagnetic materials, eddy current flaw detection is mainly used for nondestructive testing of such thin nonmagnetic tubes.

Eddy current inspection on the heat exchanger tube flows a high frequency (tens of tens to hundreds of ohms) of current into the coil of the eddy current probe inserted inside the tube to form an eddy current in the tube, and the eddy current due to the change in the geometry of the tube, the conductivity of the material, the defect, etc. This is done by measuring the presence and size of defects by detecting changes in the system. As an eddy current probe for performing such a test, a bobbin probe and a rotating pancake coil (RPC) probe are generally used.

The bobbin transducer is a device in which two coils having the same coil axis as the tube axis are wound annularly in one body, and have a constant gap between the coils. Inspection with bobbin probes has the advantage of fast inspection speed, but has the disadvantage of being sensitive to axial cracking but insensitive to circumferential crack detection.

The rotary probe is inspected by rotating the fuselage drive having a pancake-shaped coil whose coil axis is perpendicular to the tube plane. Inspection using a rotary probe has excellent defect detection performance in the axial and circumferential directions, but has a disadvantage in that the inspection speed is very slow.

An array eddy current transducer is one that maintains the advantages of both of these transducers and compensates for them. Array The eddy current transducer has a coil arranged in a cylindrical body two-dimensionally in the circumferential direction according to the inspection object. Therefore, by electronically controlling each coil to transmit and receive signals in various directions, an eddy current test can be performed by electronic scanning on the region where the coils are arranged without mechanical rotation. By the electronic scanning, the inspection using the eddy current transducer has the advantages of rapid inspection of the bobbin transducer, and the advantage of the rotary probe that can detect circumferential defects and obtain 2D / 3D stereoscopic images of the corresponding site. At the same time, the inspection time is shortened, and the inspection reliability is improved.

1 is a view showing a conventional array eddy current transducer.

Referring to FIG. 1, in a conventional array eddy current transducer, a plurality of coils 100 are densely arranged in a plurality of rows in the circumferential direction of the array eddy current transducer. In the eddy current inspection, a transmission / reception mode is used in which one coil excites the eddy current and the other coil detects magnetism by the eddy current. At least one of the plurality of rows is used to detect circumferential cracks, and two or three rows are used to detect circumferential and axial cracks. Also used is a multiplexer, which is a switching device that selects a transmit / receive coil for electronic scanning.

FIG. 2 is a diagram illustrating the operation of a conventional array eddy current probe. In the coil arrangement illustrated in FIG. 1, one row for circumferential defect detection is developed in a plane, and each time slot for flaw detection of the inner surface of the heat exchanger tube is performed. A diagram illustrating a transmission / reception pattern and a configuration for implementing the same.

Referring to FIG. 2, the coil 210 of the array eddy current transducer is connected to the multiplexer 221 for magnetic excitation (transmission) and the multiplexer 222 for magnetic field detection (reception) of the signal switching device 220, respectively. The signal switching device 220 includes a magnetic excitation multiplexer 221, a magnetic field detection multiplexer 222, and a multiplexer controller 223, and is connected to the main body 230 through a lead wire. Therefore, in performing the electronic scan, the coil used as the magnetic field detecting element is used as the magnetic excitation element again. However, since the multiplexer 221 for magnetic excitation and the multiplexer 222 for magnetic field detection are used together with one coil 210 as described above, signal interference due to a high amplitude magnetic excitation signal is received. Signal quality worsens. In addition, since each coil 210 should have the same electrical characteristics, it is difficult to use a magnetic element such as a Hall sensor, a large magnetoresistive sensor, or a coil in the form of a printed circuit board (PCB) as a magnetic field detection element. have.

The technical problem of the present invention is to provide an arrayed eddy current probe and an eddy current flaw detection method using the same in which the transceiver is isolated to improve the signal quality by reducing the signal interference by the self-excitation signal to simplify the existing wiring more .

Another technical problem of the present invention is to provide an array eddy current probe insulated from a transceiver which can be used in combination of heterogeneous elements, and an eddy current flaw detection method using the same.

It is still another object of the present invention to provide an array eddy current probe insulated from a transceiver for performing eddy current flaw detection and a eddy current flaw detection method using the same.

According to one aspect of the invention, the array eddy current transducer is a body, a plurality of self-excited elements arranged in a row along the circumference of the body and a position spaced apart from the coil for the self-excited coil by a predetermined interval on the one row It may include a plurality of magnetic field detection elements disposed in.

According to one side, the self-exciting element may be a coil of any one form of circular, elliptical, and square shape.

According to another aspect, the magnetic field detection element is a coil in the form of any one of a circle, oval and square, such as the magnetic excitation element, or a coil, a hall sensor and a large magnetoresistive element in the form of a PCB (Printed Circuit Board) It can be either.

According to another aspect, the magnetic excitation element and the magnetic field detection element may be alternately arranged two at equal intervals on the one column.

According to another aspect, the array eddy current transducer is a magnetic excitation multiplexer connected to the magnetic excitation element, the magnetic field multiplexer connected to the magnetic field detection element and the magnetic excitation according to the selection signal received from the eddy current inspection device The apparatus may further include a controller for selecting at least one of the device and the magnetic field detection device.

According to another aspect, the magnetic excitation element and the magnetic field detection element may be separately connected to the magnetic excitation multiplexer and the magnetic field multiplexer, respectively.

According to another aspect, the method may further include a signal amplifier connected to the magnetic field multiplexer for amplifying the magnetic field signal detected by the magnetic field detection element.

According to another aspect, the magnetic field signal may be detected by the magnetic field detection element at a position separated by one element on the one column from the magnetic excitation element that generated the eddy current among the plurality of magnetic field detection elements.

According to another aspect, the self-excited element may generate an eddy current using the alternating current received from the eddy current inspection device.

According to another aspect of the present invention, an eddy current flaw detection method using an array eddy current probe generates an eddy current by applying an alternating current to at least one of a plurality of self-excited elements arranged in a row along the circumference of the array eddy current probe. Step, spaced apart from the self-excited element that generated the eddy current on the one column of the plurality of magnetic field detection elements disposed in a position spaced apart from the self-excited coil by a predetermined interval on the one column by a predetermined interval The method may include selecting a magnetic field detecting element disposed at a predetermined position and detecting a magnetic signal using the selected magnetic field detecting element.

Since the magnetic excitation portion and the magnetic field detection portion are clearly insulated from each other, the existing wiring can be simplified and the signal interference due to the magnetic excitation signal can be reduced to improve the signal quality.

Since the magnetic excitation element group and the magnetic field detection element group are clearly distinguished, heterogeneous elements can be used in combination, so that the size of the transducer can be reduced and the coil can be more densely constructed.

A smaller number of timeslots can be used to detect one round of the inner surface of the heat exchanger tube, allowing the use of multiplexers with fewer channels, and a faster inspection speed in one cycle, thus increasing the feeder speed.

1 is a view showing a conventional array eddy current transducer.

FIG. 2 is a planar view of a coil arrangement circumferential defect detection shown in FIG. 1 for explaining the operation of a conventional array eddy current transducer in a plane to transmit / receive each time slot for flaw detection of the inner surface of a heat exchanger tube. A diagram showing a pattern and a configuration for implementing it.

3 is a view showing an array eddy current transducer according to an embodiment of the present invention.

4 is a diagram illustrating a transmission / reception pattern and a configuration of time slots of an array eddy current probe according to an embodiment of the present invention.

5 is an exploded view of an array eddy current transducer device having a heterogeneous combination type according to another embodiment of the present invention.

FIG. 6 is a diagram illustrating a transmission / reception pattern and a configuration of time slots of an array eddy current probe according to another embodiment of the present invention.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification. In addition, throughout the specification, when a part is said to "include" a certain component, it means that it can further include other components, except to exclude other components unless specifically stated otherwise.

Referring to FIG. 3, the array eddy current transducer 300 according to the present invention includes a plurality of magnetic excitation elements 310 arranged in a row along a circumference of the cylindrical body, that is, in a circumferential direction, and a magnet on the one row. The excitation coil 310 may include a plurality of magnetic field detecting elements 320 disposed at positions spaced apart by a predetermined interval. The magnetic excitation element 310 may generate an eddy current in the body, and the magnetic field detection element 320 may detect magnetism. Here, the self-exciting element 310 may be a coil of any one of a circle, an ellipse, and a rectangle. The magnetic field detecting element 320 may be a coil of any one of circular, elliptical, and square shapes, such as the magnetic excitation element 310, or a coil, a hall sensor, and a large magnetoresistance (GMR) in the form of a printed circuit board (GMR). : Giant Magneto Resistance) can be any one of the elements. That is, in FIG. 3, a circular coil is used as both the magnetic excitation element and the magnetic field detection element. However, the magnetic excitation element group and the magnetic field detection element group are clearly insulated and distinguished as magnetic field detection elements. PCB type coils, Hall sensors, large magnetoresistive elements and the like can be used.

In addition, in FIG. 3, a total of 16 magnetic excitation elements 310 and the magnetic field detection elements 320 are alternately arranged at equal intervals on one column in an array eddy current transducer, but the number of transmission and reception elements is required. It can be increased or decreased accordingly.

In addition, although FIG. 3 illustrates an interpolated probe inserted into a heat exchanger tube provided in a nuclear power plant as an example, the coil structure of FIG. 3 may be applied to a through type eddy current transducer.

Referring to FIG. 4, the magnetic excitation elements a, b, e, f, I, j, m and n of the plurality of elements 410 and the magnetic field detection elements c, d, g, h, k, l, o. p) may be separately connected to the magnetic excitation multiplexer 421 and the magnetic field detection multiplexer 422 included in the eddy current signal switching device 420, respectively. The eddy current signal switching device 420 may be embedded in the main body 430 of the eddy current inspection device, or may be configured as a separate device or interpolated inside the array eddy current transducer.

The self-excited multiplexer 421 is connected to the elements of the self-excited elements (a, b, e, f, I, j, m, n) for the magnetic excitation corresponding to the alternating current supplied from the main body 430 through the lead wire It can be applied to the device. The self-excited elements (a, b, e, f, I, j, m, n) may generate an eddy current using the alternating current received through the self-excited multiplexer 421.

The magnetic field detecting multiplexer 422 is connected to the magnetic field detecting elements c, d, g, h, k, l, o.p and the amplifier 424 so that the magnetic field detecting elements c, d, g, h, The magnetic field signal detected by k, l, o. p) may be provided to the signal amplifier 424. Here, the magnetic field signal is a magnetic field detection element at a position spaced apart by one element from the magnetic excitation element that generated the eddy current among the plurality of magnetic field detection elements (c, d, g, h, k, l, o. P). Can be detected by. For example, when the controller 423 controls the magnetic excitation multiplexer 421 to generate an eddy current in the magnetic excitation element e, the magnetic field is detected so that the magnetic signal is detected by the magnetic field detection elements c and g. The detection multiplexer 422 can be controlled.

The controller 423 may select at least one of the magnetic excitation element and the magnetic field detection element according to the selection signal received from the main body 43 of the eddy current inspection apparatus.

The signal amplifier 424 may be connected to the magnetic field multiplexer 422 to amplify the magnetic field signal detected by the magnetic field detection elements c, d, g, h, k, l, and p.

For example, the controller 423 allows an alternating current to be applied to at least one of the plurality of self-excited elements arranged in one row along the circumference of the array eddy current transducers, thereby causing an eddy current to be generated in the self-excited element. At a position spaced apart from the self-excited element that generated the eddy current on the one column among the plurality of magnetic field detection elements disposed at a position spaced apart from the coil for self-excited by a predetermined interval on one column The magnetic field detecting element may be selected to detect a magnetic signal through the magnetic field detecting element.

Specifically, each of the

multiplexers

421 and 422 receives a selection signal for selecting any one of the magnetic excitation element and the magnetic field detection element from the main body 430, and sequentially 1s each time slot through the controller 423. You can switch from channel 1 to channel n, where n is a natural number. In this case, the selection signal may be a signal of m (where m is a natural number) or a continuous signal of a square pulse. Each

multiplexer

421, 422 may select a coil to enable inspection in the order shown in FIG. 4 through switching. In FIG. 4, "T" represents a transmitting element and "R" represents a receiving element.

A lead wire is connected to the self-excited multiplexer 421, and an alternating current may be applied to excite the magnetic field from the main body 430. When switching to the first channel by the controller 423 in the first time slot, the magnetic excitation element (a) disposed at the first of the plurality of elements 410 is connected, and an eddy current is generated by the element (a). do. Thereafter, the magnetic field due to the changed eddy current is sensed through the magnetic field detecting elements c, g, k and o at positions where one element is spaced to the left and right of the magnetic excitation elements a and i. At this time, each magnetic field detection element (c, g, k, o) is connected to the magnetic field multiplexer 422. The magnetic field signal detected by the magnetic field detecting elements c, g, k, and o is amplified by a signal amplifier 424 connected to the magnetic field multiplexer 422, and the amplified signal is a main body 430 through a lead wire. Is delivered.

In the second time slot, the controller 423 switches to the second channel and is connected to the second self-excited elements b and j to generate eddy currents in the corresponding element. Then, as in the first time slot, the magnetic field due to the eddy current changed through the magnetic field detecting elements d, h, l, and p at positions where one element is spaced apart from the left and right sides of the corresponding magnetic excitation elements b and j. Is detected.

When switched to the third channel by the controller 423 in the third time slot, it is switched to the self-excited elements (e, m) at positions separated by two elements, and transmission and reception are performed as in the above procedure.

By repeating the above procedure, the output signal for each time slot is sequentially transmitted to the main body 430 through one lead through switching of the magnetic field multiplexer 422 for one period.

Therefore, the array eddy current probe according to an embodiment of the present invention can detect one wheel of the inner surface of the heat exchanger tube with four time slots for one cycle of flaw detection based on 16 elements. Through this, multiplexers 421 and 422 having a reduced number of channels can be used, and since the one-cycle inspection speed is high, the feeding speed of the transducer can be increased. In addition, since the magnetic excitation portion composed of the magnetic excitation element and the corresponding multiplexer 421 and the magnetic field detection portion composed of the magnetic detection element and the multiplexer 422 are clearly separated from each other, it is possible to simplify and simplify the existing wiring. It is possible to obtain an effect of improving signal quality by reducing signal interference due to an excitation signal.

5 is an exploded view of an array eddy current transducer device having a heterogeneous combination type according to another embodiment of the present invention. FIG. 5 illustrates an example in which a heterogeneous element different from the magnetic excitation element 510 is used as the magnetic field detection element 520 in the array eddy current probe. In this case, the size of the array eddy current transducer can be reduced or more compactly constructed.

In FIG. 4, the transmission and reception is divided into two zones as an example. However, as shown in FIG. 6, the time slot may be increased without dividing the zones as shown in FIG. 6. In this case, since the number of

multiplexers

621 and 622 and the amplifier 624 included in the eddy current signal switching device 620 is reduced, the eddy current signal switching device 620 can be miniaturized. In this way, the wiring between the magnetic field detecting element and the multiplexer and the number of channels of the multiplexer can be changed as long as the transmission / reception pattern is the same as necessary.

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and changes without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present invention.

Claims

In array eddy current transducer,

Body;

A plurality of self-exciting elements arranged in one row along the circumference of the body; And

A plurality of magnetic field detection elements disposed at a position spaced apart from the coil for self-excitation by a predetermined interval on the one row;

Array eddy current transducer comprising a.
The method of claim 1,

The magnetic excitation element,

An array eddy current transducer, characterized in that the coil of any one of the circular, elliptical and square form.
The method of claim 1,

The magnetic field detection element,

Like the magneto-excitation element, an array eddy current probe, characterized in that any one of a coil of the form of round, oval and square, or a coil of the PCB (Printed Circuit Board) form, a Hall sensor and a large magnetoresistive element.
The method of claim 1,

And said magnetic excitation element and said magnetic field detection element are arranged alternately two at equal intervals on said one row.
The method of claim 1,

A self-excited multiplexer connected to the self-excited element;

A magnetic field multiplexer connected to the magnetic field detection element; And

And an controller for selecting at least one of the magnetic excitation element and the magnetic field detection element according to the selection signal received from the eddy current inspection device.
The method of claim 5,

And the magnetic excitation element and the magnetic field detection element are separately connected to the magnetic excitation multiplexer and the magnetic field detection multiplexer, respectively.
The method of claim 5,

And a signal amplifier coupled to the magnetic field multiplexer for amplifying the magnetic field signal detected by the magnetic field detection element.
The method of claim 7, wherein

The magnetic field signal is,

The array eddy current probe of claim 4, wherein the magnetic field detection element is detected by a magnetic field detection element spaced apart one by one from the magnetic excitation element generating the eddy current among the plurality of magnetic field detection elements.
The method of claim 5,

The magnetic excitation element,

And an eddy current is generated using an alternating current received from the eddy current inspection device.
In the eddy current flaw detection method using the array eddy current probe,

Generating an eddy current by applying an alternating current to at least one of a plurality of self-excited elements arranged in a row along the circumference of the array eddy current probe;

A position spaced apart from the magnetic excitation element that generates the eddy current on the one column of the plurality of magnetic field detection elements disposed at a position spaced apart from the coil for the magnetic excitation on the one column by a predetermined interval; Selecting a magnetic field detecting element disposed in the; And

Detecting a magnetic signal using the selected magnetic field detecting element;

Eddy current inspection method comprising a.
The method of claim 10,

The plurality of self-excited elements,

Eddy current inspection method, characterized in that the coil of any one type of circular, elliptical and square coils.
The method of claim 10,

The plurality of magnetic field detection elements,

Like the magneto-excitation element, any one of a coil in the form of a circle, an ellipse, and a square, or an eddy current inspection method, characterized in that any one of a coil (PCB), a hall sensor and a large magnetoresistive element of the PCB (Printed Circuit Board) type .
The method of claim 10,

And the magnetic excitation element and the magnetic field detection element are alternately arranged two by equal intervals on the one row.
The method of claim 10,

And the plurality of magnetic excitation elements and the plurality of magnetic field detection elements are separately connected to the magnetic excitation multiplexer and the magnetic field detection multiplexer, respectively.
The method of claim 10,

And amplifying the magnetic signal detected by the selected magnetic field detecting element.
The method of claim 10,

The selecting step,

And selecting a magnetic field detecting element disposed at a position spaced apart by one element on the one column from the magnetic excitation element generating the eddy current.