JP2018146247A - Eddy current flaw detector and eddy current flaw detection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an eddy current flaw detector capable of improving detection accuracy of a flaw formed on a wall surface of a pipeline.SOLUTION: An eddy current flaw detector includes a coil controller capable of performing first selection processing to select a first coil group consisting of four coils including two coils adjacent to two coils of a first coil row 12, and first flaw detection processing to allow a coil positioned on one side in a predetermined direction in the first coil row 12 and a coil positioned on the other side in a predetermined direction in a second coil row 14 among the four coils 4 selected in the first selection processing to function as exciting coils and also to allow a coil positioned on the other side in a predetermined direction in the first coil row 12 and a coil positioned on one side in a predetermined direction in the second coil row 14 to function as detection coils 4.SELECTED DRAWING: Figure 4

Description

  The present disclosure relates to an eddy current flaw detection apparatus and a eddy current flaw detection method for flaw detection on wall surfaces such as pipes and fins.

  For piping provided in conventional boilers, HRSG (exhaust heat recovery boiler for gas turbines), etc., cracks may occur in the walls of the piping and fins due to, for example, thermal fatigue and creep fatigue. In order to detect such cracks, eddy current testing (ECT: Eddy Current Testing) is performed.

  Patent Document 1 describes an example of an eddy current flaw detector for performing such an eddy current flaw inspection. Specifically, the eddy current flaw detector described in Patent Document 1 includes a multi-coil probe that scans a plurality of coils arranged in two rows in a staggered manner. A channel composed of one excitation coil and one detection coil is assigned from the plurality of coils, and flaw detection measurement is performed on the wall surface of the pipe while switching the channels. And the technique of reducing the noise of the image obtained as a flaw detection result by performing a correction process with respect to the measured value measured for every channel is disclosed.

Japanese Patent Laid-Open No. 2006-205902

  However, the eddy current flaw detector described in Patent Document 1 can flaw a wide range by switching channels, and performs correction processing on the measured value for each channel to change between different channels. Although it prevents the interference of eddy currents due to, flaws formed on the wall surface of piping etc. are detected by a channel in which one excitation coil and one detection coil are linearly arranged, and the detection accuracy is Not enough.

  At least some embodiments of the present invention have been made in view of the above-described prior art, and enable a wide range of flaw detection by arranging a plurality of coils, and cause interference of eddy currents between the plurality of coils. An object of the present invention is to provide an eddy current flaw detection apparatus and an eddy current flaw detection method that can improve the detection accuracy of flaws formed on a wall surface of a pipe or the like while preventing the occurrence of flaws.

  (1) An eddy current flaw detection apparatus according to at least one embodiment of the present invention is an eddy current flaw detection apparatus for flaw detection on a wall surface of a pipe or the like, and is disposed on a plate-like main body portion and a surface of the main body portion. A plurality of coils, a first coil row in which at least three or more coils are arranged in a predetermined direction, and a second coil row in which at least three or more coils are arranged in the predetermined direction. A plurality of coils including a second coil row arranged adjacent to one coil row, and a coil controller, wherein two of the plurality of coils adjacent to each other in the first coil row; and A first selection for selecting a first coil group consisting of four coils including two coils adjacent to each other in the second coil row, including two coils adjacent to the two coils in the first coil row. Among the four coils selected in the process and the first selection process, the coil located on one side of the predetermined direction in the first coil row, and the other side of the predetermined direction in the second coil row And the coil located on the other side of the predetermined direction in the first coil row, and the coil in the second coil row. A coil controller capable of executing a first flaw detection process that causes a coil located on one side in a predetermined direction to function as a detection coil that detects a change in the eddy current.

  According to the configuration of (1) above, a plurality of coils are arranged on the surface of the plate-like main body. The plurality of coils include a first coil row in which at least three or more coils are arranged in a predetermined direction, and at least three or more coils are arranged in a predetermined direction, and are arranged adjacent to the first coil row. A second coil row. For this reason, flaw detection can be performed over a wide range in a predetermined direction with respect to the wall surface of the pipe.

  Further, according to the configuration of (1) above, the coil controller includes: a coil located on one side in a predetermined direction in the first coil row in the first coil group selected by the first selection process; The coil located on the other side in the predetermined direction in the coil row is caused to function as an exciting coil that generates eddy current on the wall surface of the pipe. Further, among the first coil group selected by the first selection process, the coil positioned on the other side in the predetermined direction in the first coil row and the coil positioned on the one side in the predetermined direction in the second coil row are swirled. It functions as a detection coil that detects a change in current. Thus, since the eddy current flaw inspection is performed by the first coil group selected by the first selection process, it is possible to prevent eddy current interference between different coil groups.

  Further, according to the configuration of (1) above, an eddy current is generated on the wall surface of the pipe or the like by the two coils functioning as the excitation coil, whereby the eddy current is generated on the wall surface of the pipe or the like by one coil functioning as the excitation coil. Compared with the case where it makes it generate | occur | produce, it can enlarge the change of the eddy current by the flaw currently formed in wall surfaces, such as piping. Moreover, since the change of the eddy current is detected by two coils functioning as a detection coil, one coil functioning as a detection coil with respect to one coil functioning as an excitation coil as described in Patent Document 1 Compared with the case where a change in eddy current is detected by a coil, the detection accuracy of a flaw formed on the wall surface of the pipe can be greatly increased.

  (2) In some embodiments, in the configuration of (1), the coil controller functions as the excitation coil or the detection coil in the first flaw detection process after the execution of the first flaw detection process is completed. In the first flaw detection process, the coil located on the other side of the first coil row in the predetermined direction and the coil adjacent to the coil on the other side of the first coil row. The coil functioning as the excitation coil or the detection coil, the coil located on the other side in the predetermined direction in the second coil row, and on the other side in the second coil row with respect to the coil A second selection process for selecting a second coil group including four coils including adjacent coils is executed.

  According to the configuration of (2) above, the coil controller performs the second selection process so that a continuous second coil group is selected in a predetermined direction with respect to the first coil group selected in the first selection process. Run. For this reason, since the flaw formed on the wall surface of the pipe or the like is continuously detected in a predetermined direction, the detection accuracy of the flaw formed on the wall surface of the pipe or the like can be increased.

  (3) In some embodiments, in the configuration of the above (2), the coil controller may select one of the four coils selected in the second selection process in the predetermined direction in the first coil row. A coil located on the side and a coil located on the other side in the predetermined direction in the second coil row function as an excitation coil for generating an eddy current in the wall surface of the pipe, and in the first coil row A second flaw detection process is performed in which the coil located on the other side in the predetermined direction and the coil located on the one side in the predetermined direction in the second coil row function as a detection coil for detecting a change in the eddy current. .

  According to the configuration of (3) above, the second flaw detection process includes exciting a coil located on one side of the first coil row in the predetermined direction and a coil located on the other side of the second coil row in the predetermined direction. It is functioning as. For this reason, eddy currents in substantially the same direction as the eddy currents generated by the two coils functioning as the excitation coils in the first flaw detection process can be generated by the two coils functioning as the excitation coils in the second flaw detection process.

  (4) In some embodiments, in any one of the configurations (1) to (3), the coil located in the first coil row and the coil located in the second coil row are mutually They are shifted in the predetermined direction.

  According to the knowledge of the present inventors, the coil located in the first coil row and the coil located in the second coil row are shifted from each other in a predetermined direction (for example, staggered), It has been found that the defect signal due to eddy current changes is increased. For this reason, according to the configuration of (4) above, the coil located in the first coil row and the coil located in the second coil row are arranged so as to be shifted from each other in a predetermined direction. The detection accuracy of the formed flaw can be increased.

  (5) In some embodiments, in any one of the configurations (1) to (4), the coil has a rectangular outer peripheral edge.

  According to the knowledge of the present inventors, it has been found that a coil functioning as a detection coil can acquire a signal with high resolution by arranging a plurality of coils densely. According to the configuration of (5) above, since the outer peripheral edge has a rectangular shape, a plurality of coils can be arranged densely and formed on the wall surface of the pipe, for example, as compared with the case where the outer peripheral edge has a circular shape. It is possible to improve the detection accuracy of the scratches that are made.

  (6) In some embodiments, in the configuration of (5), the outer peripheral edge of the coil has a rectangular shape, and the coil has a short direction of the outer peripheral edge along the predetermined direction. , Disposed on the surface of the main body.

  According to the knowledge of the present inventors, when the outer peripheral edge of the coil has a rectangular shape, the outer peripheral edge has a short shape with respect to a predetermined direction, thereby improving the defect detectability by the coil functioning as the detection coil. It has been found that it can. For this reason, according to the configuration of (6) above, the outer peripheral edge of the coil has a rectangular shape, and the coil is arranged on the surface of the main body so that the short direction of the outer peripheral edge is along the predetermined direction. The detection accuracy of the flaw formed on the wall surface of the pipe can be increased.

  (7) In some embodiments, in any one of the configurations (1) to (6), the main body is formed of a flexible material.

  According to the configuration of (7) above, the main body has flexibility, so that the main body can be deformed according to the shape of the wall surface of the pipe.

  (8) In some embodiments, in any one of the configurations (1) to (7), at least a part of the surface of the coil opposite to the surface facing the main body portion is provided on the surface of the coil. A surface protective film is formed.

  According to the configuration of the above (8), when the coil is brought close to the wall surface of the pipe, at least a part of the surface opposite to the surface facing the main body portion is damaged by coming into contact with the wall surface of the pipe or the like. This can be prevented.

  (9) An eddy current flaw detection method according to at least one embodiment of the present invention includes a plate-like main body portion and a plurality of coils arranged on the surface of the main body portion, wherein at least three or more coils are arranged in a predetermined direction. A first coil row arranged; and a second coil row in which at least three or more coils are arranged in the predetermined direction, the second coil row being arranged adjacent to the first coil row. An eddy current flaw detection method in which a wall surface of a pipe is flawed by an eddy current flaw detector comprising a plurality of coils, wherein two coils adjacent to each other in the first coil row among the plurality of coils, and A first selection process for selecting a first coil group consisting of four coils that are adjacent to each other in the second coil row and include two coils adjacent to the two coils in the first coil row. A first coil group selection step for executing the coil, a coil located on one side in the predetermined direction in the first coil row among the four coils selected in the first selection process, and the second coil A coil located on the other side of the predetermined direction in a row functions as an exciting coil for generating an eddy current on the wall surface of the pipe, and a coil located on the other side of the predetermined direction in the first coil row; and And a first flaw detection processing step for executing a first flaw detection process for causing a coil located on one side in the predetermined direction in the second coil row to function as a detection coil for detecting a change in the eddy current.

  According to the above method (9), at least three or more coils are arranged in a predetermined direction, and at least three or more coils are arranged in a predetermined direction and adjacent to the first coil row. The first coil group selection step and the first flaw detection processing step are performed on a plurality of coils including the second coil row arranged in this manner. For this reason, flaw detection can be performed in a wide range with respect to the predetermined direction.

  According to the method of (9) above, in the first flaw detection processing step, out of the first coil group selected by the first selection processing, the coil located on one side in the predetermined direction in the first coil row, and The coil located on the other side in the predetermined direction in the second coil row is caused to function as an exciting coil that generates an eddy current on the wall surface of the pipe. Further, among the first coil group selected by the first selection process, the coil positioned on the other side in the predetermined direction in the first coil row and the coil positioned on the one side in the predetermined direction in the second coil row are swirled. It functions as a detection coil that detects a change in current. Thus, since the eddy current flaw inspection is performed by the first coil group selected by the first selection process, it is possible to prevent eddy current interference between different coil groups.

  Further, according to the method (9), in the first flaw detection processing step, an eddy current is generated on the wall surface of the pipe by the two coils functioning as the exciting coil, whereby the eddy current is generated by one coil functioning as the exciting coil. Compared with the case where an electric current is generated on the wall surface of the pipe, the change in eddy current due to scratches formed on the wall surface of the pipe can be increased. Moreover, since the change of the eddy current is detected by two coils functioning as a detection coil, one coil functioning as a detection coil with respect to one coil functioning as an excitation coil as described in Patent Document 1 Compared with the case where a change in eddy current is detected by a coil, the detection accuracy of a flaw formed on the wall surface of the pipe can be greatly increased.

  According to at least one embodiment of the present invention, it is possible to perform a wide range of flaw detection by arranging a plurality of coils, and to prevent the occurrence of eddy current interference between the plurality of coils, while preventing the occurrence of eddy current interference between the plurality of coils. It is possible to provide an eddy current flaw detection apparatus and an eddy current flaw detection method that can improve the accuracy of detection of flaws formed on the surface.

1 is a schematic configuration diagram of an eddy current flaw detector according to an embodiment of the present invention. It is the top view which showed the some coil arrange | positioned on the surface of the main-body part which concerns on one Embodiment of this invention. It is a block diagram which shows the structure of the coil controller which concerns on one Embodiment of this invention. It is explanatory drawing for demonstrating the process performed by the coil controller which concerns on one Embodiment of this invention. It is explanatory drawing for demonstrating the process performed by the coil controller which concerns on one Embodiment of this invention. It is a figure when the main-body part which concerns on one Embodiment of this invention is visually recognized from the scanning direction. It is a figure when the main-body part which concerns on one Embodiment of this invention is visually recognized from the predetermined direction. It is a figure when the main-body part which concerns on one Embodiment of this invention is visually recognized from the predetermined direction. It is a flowchart of the eddy current flaw detection method which concerns on one Embodiment of this invention.

Hereinafter, some embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described in the embodiments or shown in the drawings are not intended to limit the scope of the present invention, but are merely illustrative examples. Absent.
For example, expressions expressing relative or absolute arrangements such as “in a certain direction”, “along a certain direction”, “parallel”, “orthogonal”, “center”, “concentric” or “coaxial” are strictly In addition to such an arrangement, it is also possible to represent a state of relative displacement with an angle or a distance such that tolerance or the same function can be obtained.
In addition, for example, expressions representing shapes such as quadrangular shapes and cylindrical shapes not only represent shapes such as quadrangular shapes and cylindrical shapes in a strict geometric sense, but also within the range where the same effect can be obtained. A shape including a chamfered portion or the like is also expressed.
On the other hand, the expressions “comprising”, “comprising”, “comprising”, “including”, or “having” one constituent element are not exclusive expressions for excluding the existence of the other constituent elements.

  FIG. 1 is a schematic configuration diagram of an eddy current flaw detector according to an embodiment of the present invention.

  As shown in FIG. 1, an eddy current flaw detector 1 according to an embodiment of the present invention is a device for flaw-detecting a wall surface 101 of a pipe 100, and includes a plate-like main body 2 and the main body 2. A plurality of coils 4 disposed on the surface 2a and a coil controller 6 are provided.

  In the embodiment shown in FIG. 1, the eddy current flaw detector 1 is attached to a gripping portion 8 having a rod shape, a cable 10 connecting the gripping portion 8 and the coil controller 6, and the tip of the gripping portion 8. And a support portion 5. And the main-body part 2 is attached to this support part 5 on the opposite side to the side in which the holding part 8 is attached. As described above, the probe 3 includes the main body 2, the plurality of coils 4, and the support 5.

  The coil 4 includes a so-called upper coil having a coil surface facing the wall surface 101 of the pipe 100.

  The coil controller 6 is electrically connected to the coil 4 via the cable 10, and transmits an electrical signal to the coil 4 to cause the coil 4 to generate an eddy current in the wall surface 101 of the pipe 100, Or it can be made to function as a detection coil which detects the change of this eddy current.

  FIG. 2 is a plan view showing a plurality of coils arranged on the surface of the main body according to the embodiment of the present invention.

  As shown in FIG. 2, the plurality of coils 4 includes a first coil row 12 in which at least three or more coils 4 are arranged in a predetermined direction. The plurality of coils 4 is a second coil row 14 in which at least three or more coils 4 are arranged in a predetermined direction, and the second coil row 14 arranged adjacent to the first coil row 12 is arranged. Including.

In the embodiment shown in FIG. 2, the coils 4 a, 4 b, 4 c, 4 d, and 4 e included in the first coil row 12 are in the same position in the direction (scanning direction) orthogonal to the predetermined direction. It is arranged. Further, the coils 4f, 4g, 4h, 4i, and 4j included in the second coil row 14 are arranged so as to be at the same position in the scanning direction. The coils 4a, 4b, 4c, 4d, and 4e included in the first coil row 12 are more in the scanning direction than the coils 4f, 4g, 4h, 4i, and 4j included in the second coil row 14, respectively. It is arranged on the front side.
A plate-like pedestal 15 to be described later is attached to the surface 2 a of the main body 2, and the coil 4 is attached to the pedestal 15, whereby the coil 4 is disposed on the surface 2 a of the main body 2.

  In the present disclosure, as illustrated in FIG. 2, the coil 4a located on the most one side in a predetermined direction among the coils 4a, 4b, 4c, 4d, and 4e included in the first coil row 12 is described as the first coil 4a. To do. Then, the coils 4b, 4c, 4d, and 4e that are sequentially positioned from the first coil 4a toward the other side in the predetermined direction are respectively replaced with the second coil 4b, the third coil 4c, the fourth coil 4d, and the fifth coil. This will be described as 4e. Similarly, among the coils 4f, 4g, 4h, 4i, and 4j included in the second coil row 14, the coil 4f that is located on the most one side in the predetermined direction will be described as the sixth coil 4f. Then, the coils 4g, 4h, 4i, and 4j, which are sequentially positioned from the sixth coil toward the other side in the predetermined direction, are respectively replaced with the seventh coil 4g, the eighth coil 4h, the ninth coil 4i, and the tenth coil 4j. Will be described.

  FIG. 3 is a block diagram showing the configuration of the coil controller according to one embodiment of the present invention. FIG. 4 is an explanatory diagram for explaining processing performed by the coil controller according to the embodiment of the present invention.

  As shown in FIG. 3, the coil controller 6 includes, for example, a central processing unit (CPU 6A) including a processor, a random access memory (RAM 6B), a read only memory (ROM 6C), and an I / O interface 6D. The coil controller 6 executes, for example, a program (a first selection process, a first flaw detection process, etc. described later) stored in the ROM 6C by the CPU 6A.

  As shown in FIG. 4, the coil controller 6 includes two coils 4 adjacent to each other in the first coil row 12 and two coils 4 adjacent to each other in the second coil row 14 among the plurality of coils 4. Thus, the first selection process for selecting the first coil group G1 including the four coils 4 including the two coils 4 adjacent to the two coils 4 in the first coil row 12 is configured to be executable.

  Here, “the two coils 4 adjacent to each other in the first coil row 12” refers to the two coils 4 continuously arranged in a predetermined direction among the coils 4 included in the first coil row 12. It is. Similarly, “two coils 4 adjacent to each other in the second coil row 14” refers to the two coils 4 continuously arranged along a predetermined direction among the coils 4 included in the second coil row 14. It is. “Two coils 4 adjacent to each other in the second coil row 14 and adjacent to the two coils in the first coil row 12” are the two coils 4 in the second coil row 14. Each is arranged so as to overlap in at least one coil 4 of the two coils 4 in the first coil row 12 in a predetermined direction.

  For example, in the embodiment shown in FIG. 4, the coil controller 6 selects the first coil 4 a and the second coil 4 b that are adjacent to each other in the first coil row 12 and the sixth coil that is adjacent to each other in the second coil row 14. The coil 4f and the seventh coil 4g are selected. The sixth coil 4f is arranged so as to overlap in the predetermined direction with respect to each of the first coil 4a and the second coil 4b. The seventh coil 4g is arranged so as to overlap with the second coil 4b in a predetermined direction. As described above, the coil controller 6 performs the first selection process for selecting the first coil group G1 including the first coil 4a, the second coil 4b, the sixth coil 4f, and the seventh coil 4g.

  As shown in FIG. 4, the coil controller 6 includes the four coils 4 (first coil 4a, second coil 4b, sixth coil 4f, and seventh coil 4g) selected in the first selection process described above. The coil 4 (first coil 4a) located on one side in the predetermined direction in the first coil row 12 and the coil 4 (seventh coil 4g) located on the other side in the predetermined direction in the second coil row 14 are piped. The coil 4 (second coil 4 b) that functions as an exciting coil that generates an eddy current in the wall surface 101 of the 100 and is located on the other side in the predetermined direction in the first coil row 12 and the predetermined in the second coil row 14 The first flaw detection process is performed such that the coil 4 (sixth coil 4f) positioned on one side of the direction functions as a detection coil that detects a change in eddy current.

  In the embodiment shown in FIG. 4, the first flaw detection process is performed in which the first coil 4a and the seventh coil 4g function as excitation coils, and the second coil 4b and the sixth coil 4f function as detection coils.

  According to such an eddy current flaw detector 1 according to an embodiment of the present invention, a plurality of coils 4 are arranged on the surface 2 a of the plate-like main body 2. The plurality of coils 4 includes a first coil row 12 in which at least three or more coils 4 are arranged in a predetermined direction, and at least three or more coils 4 are arranged in a predetermined direction. 2 and a second coil row 14 arranged adjacent to 12. For this reason, flaw detection can be performed over a wide range in a predetermined direction with respect to the wall surface 101 of the pipe 100.

  Moreover, according to such an eddy current flaw detector 1 according to an embodiment of the present invention, the coil controller 6 is configured to perform a predetermined operation in the first coil row 12 in the first coil group G1 selected by the first selection process. The first coil 4 a located on one side in the direction and the seventh coil 4 g located on the other side in the predetermined direction in the second coil row 14 are caused to function as excitation coils that generate eddy currents on the wall surface 101 of the pipe 100. Further, in the first coil group G1 selected by the first selection process, the second coil 4b located on the other side of the first coil row 12 in the predetermined direction and the one side of the second coil row 14 in the predetermined direction. The 6th coil 4f located in is made to function as a detection coil which detects the change of an eddy current. Thus, since the eddy current flaw inspection is performed by the first coil group G1 selected by the first selection process, eddy current between different coil groups (for example, the first coil group G1 and the second coil group G2 to be described later). Current interference can be prevented from occurring.

  Further, according to the eddy current flaw detector 1 according to the embodiment of the present invention, the wall surface of the pipe 100 is used to generate eddy currents by the two coils 4 (first coil 4a and seventh coil 4g) functioning as excitation coils. As a result, the change in eddy current caused by scratches formed on the wall surface 101 of the pipe 100 is compared with the case where an eddy current is generated on the wall surface 101 of the pipe 100 by one coil functioning as an exciting coil. Can be bigger. Moreover, since the change of the eddy current is detected by the two coils 4 (the second coil 4b and the sixth coil 4f) that function as detection coils, they function as an excitation coil as described in Patent Document 1. Compared to a case where a change in eddy current is detected by one coil functioning as a detection coil for one coil, the detection accuracy of a flaw formed on the wall surface 101 of the pipe 100 can be greatly increased.

  FIG. 5 is an explanatory diagram for explaining processing performed by the coil controller according to the embodiment of the present invention.

  In some embodiments, as shown in FIG. 5, the coil controller 6 is configured such that after the execution of the first flaw detection process is completed, the coil 4 (first coil 4a, The second coil 4b, the sixth coil 4f, and the seventh coil 4g), the coil 4 (second coil 4b) located on the other side in the predetermined direction in the first coil row 12, and the coil 4 (second A coil 4 (third coil 4c) adjacent to the other side of the first coil row 12 with respect to the coil 4b), and a coil 4 (first coil 4a, first coil) that functions as an excitation coil or a detection coil in the first flaw detection process. The second coil 4b, the sixth coil 4f, and the seventh coil 4g), the coil 4 (seventh coil 4g) located on the other side of the second coil row 14 in the predetermined direction, and the coil Four coils (second coil 4b, third coil 4c, seventh coil 4g, and coil adjacent to the other side of the second coil row 14 with respect to the seventh coil 4g) (eighth coil 4h) A second selection process for selecting the second coil group G2 composed of the eighth coil 4h) is executed.

  In the embodiment shown in FIG. 5, the coil controller 6 executes a second selection process for selecting the second coil group G2 including the second coil 4b, the third coil 4c, the seventh coil 4g, and the eighth coil 4h. doing.

  According to such a configuration, the coil controller 6 performs the second selection process so that the continuous second coil group G2 is selected in the predetermined direction with respect to the first coil group G1 selected in the first selection process. Execute. For this reason, since the flaw formed on the wall surface 101 of the pipe 100 is continuously detected in a predetermined direction, the detection accuracy of the flaw formed on the wall surface 101 of the pipe 100 can be increased.

  In some embodiments, as shown in FIG. 5, the coil controller 6 includes four coils 4 (second coil 4b, third coil 4c, seventh coil 4g, and eighth coil selected in the second selection process). Among the coils 4h), the coil 4 (second coil 4b) located on one side in the predetermined direction in the first coil row 12 and the coil 4 (eighth) located on the other side in the predetermined direction in the second coil row 14 The coil 4h) functions as an exciting coil for generating an eddy current in the wall surface 101 of the pipe 100, and the coil 4 (third coil 4c) located on the other side in the predetermined direction in the first coil row 12; A second flaw detection process is performed in which the coil 4 (seventh coil 4g) located on one side in the predetermined direction in the two-coil row 14 functions as a detection coil that detects a change in eddy current.

  In the embodiment shown in FIG. 5, the coil controller 6 performs a second flaw detection process in which the second coil 4b and the eighth coil 4h function as excitation coils, and the third coil 4c and the seventh coil 4g function as detection coils. Running.

  According to such a configuration, the second flaw detection process includes the second coil 4b located on one side of the first coil row 12 in the predetermined direction and the eighth coil located on the other side of the second coil row in the predetermined direction. The coil 4h is made to function as an exciting coil. For this reason, eddy currents generated in the same direction as the eddy currents generated by the two coils 4 (the first coil 4a and the seventh coil 4g) that function as the excitation coils in the first flaw detection process are converted into the excitation coils in the second flaw detection process. Can be generated by two coils 4 (second coil 4b and eighth coil 4h).

  In some embodiments, the coil controller 6 uses one of the coils 4 of the first coil group G1 selected by the first selection process as an excitation coil and one of the remaining coils 4 as a detection coil. A plurality of sets of coil groups to function are formed. The plurality of coil groups are configured to execute eddy current flaw inspection at different timings.

  According to such a configuration, since the differential processing of the eddy current flaw inspection is executed by the plurality of coil groups, the detection accuracy of the flaw formed on the wall surface 101 of the pipe 100 can be increased.

  In some embodiments, as shown in FIG. 2, the coil 4 located in the first coil row 12 and the coil 4 located in the second coil row 14 are arranged so as to be shifted from each other in a predetermined direction.

  According to the knowledge of the present inventors, the coil 4 located in the first coil row 12 and the coil 4 located in the second coil row 14 are arranged so as to be shifted from each other in a predetermined direction (for example, staggered). It has been found that the defect signal due to the change in eddy current increases. For this reason, according to such a configuration, the coil 4 located in the first coil row 12 and the coil 4 located in the second coil row 14 are arranged so as to be shifted from each other in a predetermined direction. The detection accuracy of the flaw formed on the wall surface 101 can be increased.

  In addition, according to such a configuration, when the main body 2 is moved in the scanning direction, the second coil is compared with the flaw detection range that could not be detected by the coil 4 functioning as the detection coil in the first coil row 12. Detection is possible by the coil 4 functioning as a detection coil in the row 14.

  In some embodiments, as shown in FIG. 2, the plurality of coils 4 includes two adjacent centers of gravity O2 of the coils 4 included in the second coil row 14 in the predetermined direction. The coils 4 are arranged so as to be shifted from each other in a predetermined direction so as to be located at the center between the center of gravity O1 of the coil 4.

  According to the knowledge of the present inventors, the center of gravity O2 of the coil 4 included in the second coil row 14 is positioned at the center between the centers of gravity O1 of two adjacent coils 4 included in the first coil row. It has been found that the defect signal due to the change in eddy current can be maximized by being shifted from each other in a predetermined direction. For this reason, according to such a structure, the detection precision of the flaw currently formed in the wall surface 101 of the piping 100 can further be improved.

  In some embodiments, as shown in FIG. 2, the coil 4 has a rectangular outer peripheral edge 19 of the coil 4.

  According to the knowledge of the present inventors, it has been found that the coil 4 functioning as a detection coil can acquire a signal with high resolution by arranging the plurality of coils 4 densely. According to such a configuration, since the outer peripheral edge 19 has a rectangular shape, for example, the plurality of coils 4 can be arranged densely compared to the case where the outer peripheral edge 19 has a circular shape, and the wall surface of the pipe 100 The detection accuracy of the scratch formed on 101 can be increased. Moreover, according to such a structure, since the some coil 4 is arrange | positioned densely, the surface area of the surface 2a of the main-body part 2 can be made compact.

  In some embodiments, as shown in FIG. 2, the outer peripheral edge 19 of the coil 4 has a rectangular shape, and the coil 4 has the main body 2 such that the short side direction of the outer peripheral edge 19 is along a predetermined direction. Arranged on the surface 2a.

  According to the knowledge of the present inventors, when the outer peripheral edge 19 of the coil 4 has a rectangular shape, the outer peripheral edge 19 has a short shape with respect to a predetermined direction. It has been found that detectability can be enhanced. For this reason, according to such a configuration, the outer peripheral edge 19 of the coil 4 has a rectangular shape, and the coil 4 is formed on the surface 2a of the main body 2 so that the short direction of the outer peripheral edge 19 is along the predetermined direction. Since it is arranged, it is possible to improve the detection accuracy of scratches formed on the wall surface 101 of the pipe 100.

  In some embodiments, the main body 2 is formed from a flexible material. Examples of the flexible material include rubber materials such as fluoro rubber, silicon rubber, nitrile rubber, ethylene propylene rubber, and ethylene propylene diene rubber, and resin materials such as fluoro resin, nylon resin, and acrylic resin. According to such a configuration, since the main body 2 has flexibility, the main body 2 can be deformed according to the shape of the wall surface 101 of the pipe 100.

  FIG. 6 is a view when the main body according to the embodiment of the present invention is viewed from the scanning direction. FIG. 7 is a view when the main body according to the embodiment of the present invention is viewed from a predetermined direction. FIG. 8 is a view when the main body according to the embodiment of the present invention is viewed from a predetermined direction.

In some embodiments, as shown in FIGS. 6 to 8, the surface protective film 16 is provided on at least a part of the surface 18 b of the coil 4 opposite to the surface 18 a facing the main body 2. Is formed. In the embodiment shown in FIGS. 6 to 8, the surface protective film 16 is formed so as to cover the entire surface 18 b opposite to the surface 18 a facing the main body 2.
In the present disclosure, the surface protective film 16 is formed of a flexible material. Thereby, when performing the flaw detection process by the eddy current flaw detection apparatus 1, it can prevent becoming a noise factor. Moreover, the surface protective film 16 has slidability and flexibility by being formed from a flexible material.

  According to such a configuration, when the coil 4 is brought close to the wall surface 101 of the pipe 100, at least a part of the surface 18 b opposite to the surface 18 a facing the main body portion 2 comes into contact with the wall surface 101 of the pipe 100. Can be prevented from being damaged.

In some embodiments, a pedestal 15 may be provided between the coil 4 and the main body 2 as shown in FIGS. 2, 6, and 7. In the embodiment shown in FIGS. 2, 6, and 7, the pedestal 15 is attached to the surface 2 a of the main body 2, and the coil 4 is attached to the pedestal 15 so that the coil 4 is the surface of the main body 2. 2a. According to such a configuration, since the pedestal 15 is provided between the coil 4 and the main body 2, the coil 4 can be easily attached to the surface 2 a of the main body 2 compared to the case where the pedestal 15 is not provided. Can be arranged.
The pedestal 15 is formed of a flexible material (rubber material or resin material) as with the main body 2. In the embodiment shown in FIGS. 2, 6 and 7, the base 15 is made of fluororubber.

  In some embodiments, as shown in FIG. 8, the coil 4 is disposed on the surface 2 a of the main body 2 by being attached to the surface 2 a of the main body 2 so as to be embedded in the main body 2. Also good. In this case, the pedestal 15 is not provided between the coil 4 and the main body 2.

  FIG. 9 is a flowchart of an eddy current flaw detection method according to an embodiment of the present invention.

  As shown in FIG. 9, the eddy current flaw detection method of the eddy current flaw detector 1 according to one embodiment of the present invention includes an n-th coil group selection step S1 (where n is a natural number of 1 or more), and an n-th flaw detection process. Step S2.

  When the eddy current flaw detector 1 starts flaw detection on the wall surface 101 of the pipe 100 (when n = 1), in the first coil group selection step S1, among the plurality of coils 4, the first coil row 12 is adjacent to each other. And two coils 4 adjacent to each other in the second coil row 14, including four coils 4 including the two coils 4 adjacent to the two coils 4 in the first coil row 12. A first selection process for selecting the first coil group G1 is executed.

  In the first flaw detection processing step S2, among the four coils 4 selected in the first selection process, the coil 4 located on one side in the predetermined direction in the first coil row 12 and the second coil row 14 The coil 4 located on the other side in the predetermined direction functions as an exciting coil for generating an eddy current in the wall surface 101 of the pipe 100, and the coil 4 located on the other side in the predetermined direction in the first coil row 12; A first flaw detection process is performed in which the coil 4 located on one side in the predetermined direction in the two-coil row 14 is caused to function as a detection coil that detects a change in eddy current.

  And after this 1st flaw detection process step S2 is completed, the coil controller 6 determines whether the flaw detection of the wall surface 101 of the piping 100 by the eddy current flaw detector 1 is complete | finished (step S3). When the flaw detection is finished (step S3: Yes), the flaw detection of the wall surface 101 of the pipe 100 by the eddy current flaw detector 1 is finished. When the flaw detection is not finished (step S3: No), 1 is added to n (that is, n = 2), and the second coil group selection step S1 is executed.

  According to the eddy current flaw detection method of the eddy current flaw detector 1 according to the embodiment of the present invention, the first coil row 12 in which at least three or more coils 4 are arranged in a predetermined direction, and at least three or more coils. For the plurality of coils 4 including the coils 4 arranged in a predetermined direction and the second coil row 14 arranged adjacent to the first coil row 12, the first coil group selection step S1 and the first coil group selection step S1 One flaw detection processing step S2 is performed. For this reason, flaw detection can be performed in a wide range with respect to the predetermined direction.

  Further, according to the eddy current flaw detection method of the eddy current flaw detection apparatus 1 according to the embodiment of the present invention, the first coil group G1 selected by the first selection process in the first flaw detection process step S2. An exciting coil that generates an eddy current on the wall surface 101 of the pipe 100 using the coil 4 positioned on one side in the predetermined direction in the first coil row 12 and the coil 4 positioned on the other side in the predetermined direction in the second coil row 14. To function as. Further, in the first coil group G1 selected by the first selection process, the coil 4 located on the other side in the predetermined direction in the first coil row 12 and the one side in the predetermined direction in the second coil row 14 are located. The functioning coil 4 is made to function as a detection coil for detecting a change in eddy current. Thus, since the eddy current flaw inspection is performed by the first coil group G1 selected by the first selection process, it is possible to prevent eddy current interference between different coil groups.

  Further, according to the eddy current flaw detection method of the eddy current flaw detector 1 according to the embodiment of the present invention, the eddy current is piped 100 by the two coils 4 functioning as the exciting coils in the first flaw detection processing step S2. As a result, the eddy current caused by scratches formed on the wall surface 101 of the pipe 100 is compared with the case where the eddy current is generated on the wall surface 101 of the pipe 100 by one coil functioning as an exciting coil. The change can be great. Moreover, since the change of the eddy current is detected by the two coils 4 functioning as the detection coils, the one coil functioning as an excitation coil as described in Patent Document 1 functions as a detection coil. Compared with the case where a change in eddy current is detected by one coil, the detection accuracy of a flaw formed on the wall surface 101 of the pipe 100 can be greatly increased.

  As described above, the eddy current flaw detection apparatus and the eddy current flaw detection method according to the embodiment of the present invention have been described. However, the present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the object of the present invention. Can be changed.

DESCRIPTION OF SYMBOLS 1 Eddy current flaw detector 2 Main-body part 2a Surface 4 Coil 4a 1st coil 4b 2nd coil 4c 3rd coil 4d 4th coil 4e 5th coil 4f 6th coil 4g 7th coil 4h 8th coil 4i 9th coil 4j 1st 10 coil 5 probe 6 coil controller 8 gripping part 10 cable 12 first coil row 14 second coil row 15 pedestal 16 surface protective film 18 surface 19 outer peripheral edge 100 pipe 101 wall surface G1 first coil group G2 second coil group S1 coil group Selection step S2 Flaw detection processing step

Claims (9)

An eddy current flaw detector for flaw detection on a wall surface of a pipe,
A plate-like body,
A plurality of coils disposed on the surface of the main body,
A first coil row in which at least three or more coils are arranged in a predetermined direction;
A plurality of coils including a second coil row in which at least three or more coils are arranged in the predetermined direction, the second coil row being arranged adjacent to the first coil row;
A coil controller,
Among the plurality of coils, two coils adjacent to each other in the first coil row, and two coils adjacent to each other in the second coil row, adjacent to the two coils in the first coil row. A first selection process for selecting a first coil group consisting of four coils including two coils, and
Of the four coils selected in the first selection process, the coil located on one side of the predetermined direction in the first coil row and the other side of the predetermined direction in the second coil row A coil that functions as an exciting coil that generates an eddy current in the wall surface of the pipe, and a coil that is positioned on the other side of the predetermined direction in the first coil row, and the predetermined direction in the second coil row; A first flaw detection process for causing a coil located on one side to function as a detection coil for detecting a change in the eddy current;
And an eddy current flaw detection device. The coil controller, after completion of execution of the first flaw detection process,
The coil functioned as the excitation coil or the detection coil in the first flaw detection process, the coil located on the other side in the predetermined direction in the first coil row, and the first with respect to the coil A coil adjacent to the other side of the coil row;
The coil functioned as the excitation coil or the detection coil in the first flaw detection process, the coil located on the other side of the predetermined direction in the second coil row, and the second with respect to the coil 2. The eddy current flaw detector according to claim 1, wherein a second selection process is performed to select a second coil group including four coils including a coil adjacent to the other side in the coil row. The coil controller
Of the four coils selected in the second selection process, the coil located on one side of the predetermined direction in the first coil row and the other side of the predetermined direction in the second coil row A coil that functions as an exciting coil that generates an eddy current in the wall surface of the pipe, and a coil that is positioned on the other side of the predetermined direction in the first coil row, and the predetermined direction in the second coil row; The eddy current flaw detection apparatus according to claim 2, wherein a second flaw detection process is performed to cause a coil located on one side to function as a detection coil that detects a change in the eddy current.   4. The vortex according to claim 1, wherein the coil located in the first coil row and the coil located in the second coil row are arranged to be shifted from each other in the predetermined direction. 5. Current flaw detector.   The eddy current flaw detector according to any one of claims 1 to 4, wherein the coil has a rectangular outer peripheral edge. The outer peripheral edge of the coil has a rectangular shape;
The eddy current flaw detector according to claim 5, wherein the coil is disposed on a surface of the main body so that a short direction of the outer peripheral edge is along the predetermined direction.   The eddy current flaw detector according to any one of claims 1 to 6, wherein the main body is formed of a flexible material.   The eddy current flaw detection according to any one of claims 1 to 7, wherein a surface protective film is formed on at least a part of a surface of the coil opposite to the surface facing the main body portion. apparatus. A plate-like body,
A plurality of coils disposed on the surface of the main body,
A first coil row in which at least three or more coils are arranged in a predetermined direction;
A plurality of coils including a second coil row in which at least three or more coils are arranged in the predetermined direction, the second coil row being arranged adjacent to the first coil row;
An eddy current flaw detection method that flaws a wall surface of a pipe by an eddy current flaw detection device comprising:
Among the plurality of coils, two coils adjacent to each other in the first coil row, and two coils adjacent to each other in the second coil row, adjacent to the two coils in the first coil row. A first coil group selection step for performing a first selection process for selecting a first coil group including four coils including two coils
Among the four coils selected in the coil group selection step, the coil located on one side of the predetermined direction in the first coil row and the other side of the predetermined direction in the second coil row A coil that functions as an exciting coil that generates an eddy current in the wall surface of the pipe, and a coil that is positioned on the other side of the predetermined direction in the first coil row, and the predetermined direction in the second coil row; An eddy current flaw detection method comprising: a first flaw detection process step for executing a first flaw detection process for causing a coil located on one side to function as a detection coil for detecting a change in the eddy current.

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