Coil module, array probe, and eddy current flaw detector

Abstract

To provide a coil module, an array probe, and an eddy current detector which can be manufactured at low cost in a short time.SOLUTION: The coil module includes: a cross coil having an annular first coil with a first axial line as a center, and a second coil forming an annular shape with a second axial line intersecting the first axial line as a center, and covering a part of an outer peripheral side of the first coil; and a case having a first storage unit extending in a direction of the first axial line and storing the first coil, and a second storage unit extending in a direction of the second axial line and storing the second coil.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a coil module, an array probe, and an eddy current flaw detection device. [Background technology]

[0002] Eddy current flaw detection is known as a method for non-destructively inspecting defects such as scratches and thinning in pipes, etc. This method has generally used a cross coil that includes an excitation coil that generates eddy currents from the inner surface to the outer surface of the pipe, a detection coil that detects disturbances in the eddy currents that occur at defective parts of the pipe, and a bobbin around which the excitation coil and the detection coil are wound (see, for example, Patent Document 1 below).

[0003] To manufacture a cross coil, the excitation coil and detection coil are alternately wound around the spool. This means that the excitation coil is first wound, and then the detection coil is wound in a direction that crosses the excitation coil, and this process must be repeated. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6288640 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when manufacturing cross coils using the above-mentioned bobbins, it is difficult to automate the process, which leads to problems such as increased manufacturing costs and a long manufacturing period. In particular, when creating an array probe for eddy current flaw detection, which requires a large number of cross coils, the time required to manufacture the cross coils is a significant bottleneck.

[0006] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a coil module, an array probe, and an eddy current flaw detection device that can be manufactured at low cost and in a short time. [Means for solving the problem]

[0007] In order to solve the above problems, the coil module of the present disclosure comprises a cross coil having a first annular coil centered on a first axis and a second annular coil centered on a second axis intersecting the first axis and covering a portion of the outer periphery of the first coil, and a case having a first housing portion extending in the first axis direction to house the first coil, and a second housing portion extending in the second axis direction to house the second coil.

[0008] The array probe according to the present disclosure comprises a plurality of the above-mentioned coil modules arranged in a first arrangement direction that intersects the first axis and the second axis and extends within the same plane, and a holding member that supports the plurality of coil modules and is formed of an elastically deformable material.

[0009] The eddy current flaw detection device according to the present disclosure comprises the above-mentioned array probe, a power supply unit that supplies alternating current to each of the first coil and the second coil, and a switch unit that switches the supply state of the alternating current between a mutual induction standard comparison method in which one of the first coil and the second coil operates as an excitation coil that generates eddy currents and the other operates as a detection coil that detects flaws by disturbances in the eddy currents, and a self-induction self-comparison method in which each of the first coil and the second coil operates as an excitation coil that generates eddy currents and as a detection coil that detects flaws by disturbances in the eddy currents. [Effects of the Invention]

[0010] According to the present disclosure, it is possible to provide a coil module, an array probe, and an eddy current flaw detector that can be manufactured at low cost and in a short time. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic diagram illustrating a configuration of an eddy current flaw detection device according to an embodiment of the present disclosure. FIG. [Figure 2] FIG. 1 is a plan view showing a configuration of an array probe according to an embodiment of the present disclosure. [Figure 3] FIG. 1 is a plan view illustrating a configuration of a coil module according to an embodiment of the present disclosure. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. [Figure 5] FIG. 4 is a cross-sectional view taken along line VV in FIG. [Figure 6] FIG. 10 is an explanatory diagram showing the relationship between the attitude of a coil module according to an embodiment of the present disclosure and the direction of eddy currents, illustrating the direction of eddy currents generated in a mutual induction standard comparison method. [Figure 7] 10A and 10B are explanatory diagrams showing the relationship between the attitude of a coil module according to an embodiment of the present disclosure and the direction of eddy currents, and are diagrams showing the direction of eddy currents generated in a self-induction self-comparison method. [Figure 8] FIG. 10 is a perspective view illustrating a first modified example of a coil module according to an embodiment of the present disclosure. [Figure 9] FIG. 10 is a perspective view illustrating a second modified example of a coil module according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0012] An eddy current flaw detector 1, an array probe 10, and a coil module 20 according to an embodiment of the present disclosure will be described below with reference to FIGS. 1 to 7. FIG.

[0013] (Configuration of eddy current flaw detection equipment) The eddy current flaw detection device 1 is a device for detecting defects (cracks or thinning) that occur in objects, such as butt welds and fillet welds of plant components in a nuclear power plant, as well as straight pipe sections and elbow sections of piping, by scanning along the surface.

[0014] As shown in FIG. 1, the eddy current flaw detector 1 includes an array probe 10, a switch unit 30, a power supply unit 40, and a flaw detector main body 50.

[0015] The array probe 10 is used by being placed on, for example, a welded portion and scanning the welded portion. The power supply unit 40 applies an AC voltage to the array probe 10, causing an AC current to be generated in the coil module 20 (described later). When the array probe 10 scans along the surface of a welded portion or the like and passes over a defective portion, a disturbance occurs in the eddy current generated by the coil module 20. The flaw detection device main body 50 is a device that digitizes or visualizes this eddy current disturbance and visually conveys it to the operator. The switch unit 30 is a device for switching the supply state of the AC current flowing through the coil module 20 (the excitation and detection method for the coils that make up the coil module 20). The switching of the operating method by the switch unit 30 will be described later.

[0016] (Array probe configuration) 2, the array probe 10 has a plurality of probe rows 60. Each probe row 60 extends in a first arrangement direction D1. The plurality of probe rows 60 (four rows in the example of FIG. 2) are arranged closely together in a second arrangement direction D2 that is perpendicular to the first arrangement direction D1.

[0017] The probe array 60 includes multiple coil modules 20 and a holding member 11 that holds the coil modules 20. The coil modules 20 are arranged at small intervals in the first arrangement direction D1. The holding member 11 holds the multiple coil modules 20 while maintaining their orientation and arrangement position. The holding member 11 is integrally formed from a resin material that is easily elastically deformable, such as elastomer or polyvinyl chloride. In other words, when pressed from the outside, the holding member 11 can conform to the curved surface of, for example, a pipe or a welded joint, and adhere tightly without gaps. Furthermore, when the pressing force is released, the holding member 11 can return to its original shape due to its elastic restoring force. In other words, the holding member 11 is flexible.

[0018] The holding member 11 is formed with a plurality of accommodation sections 12 recessed in a direction perpendicular to the first arrangement direction D1 and the second arrangement direction D2 (the direction of a third axis A3, described later). (Note that the bottoms of the accommodation sections 12 in the direction of the third axis A3 may be through-holes.) The accommodation sections 12 are arranged at small intervals in the first arrangement direction D1. The accommodation sections 12 have octagonal opening shapes. The coil modules 20 are fitted into the accommodation sections 12. More specifically, when the coil module 20 is pressed into the accommodation section 12, the inner surface of the accommodation section 12 is elastically deformed, and the coil module 20 is held in the accommodation section 12 by a restoring force based on this elastic deformation. Furthermore, the positions of the coil modules 20 in the first arrangement direction D1 differ between a pair of probe rows 60 adjacent to each other in the second arrangement direction D2. In other words, the positions of the coil modules 20 in the first arrangement direction D1 are slightly offset for each probe row 60, thereby covering the gaps between the coil modules 20. This is to prevent defective parts from being overlooked due to gaps between the coil modules 20. Although Figures 1 and 2 show an example in which the probe row 60 of the holding member 11 is divided into multiple pieces, the embodiment is not limited to this, and it is also possible to configure one holding member 11 with multiple probe rows 60 formed integrally.

[0019] (Coil module configuration) As shown in FIG. 3 , the coil module 20 includes a cross coil 21 and a case 22. The cross coil 21 includes a first coil 71 and a second coil 72. The first coil 71 has a rectangular ring shape centered on a first axis A1. The second coil 72 has a rectangular ring shape centered on a second axis A2 that is perpendicular to the first axis A1. The inner opening dimension of the second coil 72 is set to be equal to or slightly larger than the outer dimension of the first coil 71. In other words, the first coil 71 is inserted into the inner opening of the second coil 72.

[0020] Preferably, the first coil 71 and the second coil 72 are perpendicular to each other at their centers in the directions of the first axis A1 and the second axis A2. However, even if the centers of the first coil 71 and the second coil 72 are slightly misaligned, the detection accuracy is not affected or is only slightly affected. Therefore, the dimensional accuracy of the case 22, which will be described later, may have a manufacturing error that allows for such misalignment. Furthermore, the shapes of the first coil 71 and the second coil 72 are not limited to rectangular ring shapes, but may also be circular ring shapes.

[0021] The case 22 is a member that holds the cross coil 21 from the outside and maintains the shape and posture of the cross coil 21. The case 22 has a first housing portion 81 and a second housing portion 82. The first housing portion 81 houses the first coil 71, and the second housing portion 82 houses the second coil 72. As shown in FIG. 4 , the first housing portion 81 is a groove that extends in the second axis A2 direction and is recessed in the third axis A3 direction perpendicular to the first axis A1 and the second axis A2. When viewed from the third axis A3 direction, the first housing portion 81 has a rectangular shape corresponding to the projected shape of the first coil 71. The dimension of the first housing portion 81 in the second axis A2 direction is set to be the same as or slightly larger than the dimension of the first coil 71. The dimension of the first housing portion 81 in the first axis A1 direction is set to be the same as or slightly larger than the dimension of the first coil 71 in the first axis A1 direction. The dimension of first accommodating portion 81 in the direction of third axis A3 is set to be larger than the dimension of first coil 71 in the direction of third axis A3. In other words, when first coil 71 is accommodated in first accommodating portion 81, a space is formed on one side of first coil 71 in the direction of third axis A3.

[0022] As shown in FIG. 5 , the second accommodating portion 82 is a groove extending in the first axis A1 direction and recessed in the third axis A3 direction. When viewed from the third axis A3 direction, the second accommodating portion 82 has a rectangular shape corresponding to the projected shape of the second coil 72. The dimension of the second accommodating portion 82 in the first axis A1 direction is set to be the same as or slightly larger than the dimension of the second coil 72. The dimension of the second accommodating portion 82 in the second axis A2 direction is set to be the same as or slightly larger than the dimension of the second coil 72 in the second axis A2 direction. The dimension of the second accommodating portion 82 in the third axis A3 direction is set to be larger than the dimension of the second coil 72 in the third axis A3 direction. In other words, when the second coil 72 is accommodated in the second accommodating portion 82, a space is formed on one side of the second coil 72 in the third axis A3 direction.

[0023] 4, the bottom surface (second bottom surface 83) of the second housing portion 82 is recessed in the direction of the third axis A3 from the bottom surface (first bottom surface 84) of the first housing portion 81. More specifically, the dimension in the direction of the third axis A3 from the first bottom surface 84 to the second bottom surface 83 is set to be the same as or slightly larger than the protruding dimension of the second coil 72 relative to the first coil 71. Furthermore, the distance between a pair of surfaces (side surfaces 85) facing each other across the second bottom surface 83 is set to be the same as or slightly larger than the dimension of the second coil 72 in the direction of the second axis A2. The second bottom surface 83 and the pair of side surfaces 85 support and fix the second coil 72 so that a portion of the second coil 72 is surrounded by them.

[0024] As shown in FIG. 3 , the case 22 has an octagonal shape when viewed from the third axis A3. More specifically, the end faces 91 of the case 22 on both sides of the first axis A1 extend in a plane perpendicular to the first axis A1. The end faces 91 of the case 22 on both sides of the second axis A2 extend in a plane perpendicular to the second axis A2. It is desirable that the edges of the case 22 have the same dimensions as each other when viewed from the third axis A3. That is, it is desirable that the case 22 has a regular octagonal shape when viewed from the third axis A3. On the other hand, to prevent misidentification of the position of the case 22, it is also possible to adopt a configuration in which the lengths of a pair of adjacent edges are different. Furthermore, to maximize the flexibility of the holding member 11, it is also possible to configure the case 22 to have a circular shape when viewed from the third axis A3.

[0025] (About the operation method of the coil module) Next, the operation method of the coil module 20 will be described with reference to Figures 6 and 7. This coil module 20 has two selectable operation methods: a "mutual induction standard comparison method" and a "self-induction self-comparison method." Switching between these two methods is performed by appropriately changing the connection state of the wiring in the switch section 30 described above.

[0026] In the standard mutual induction comparison method, one of the first coil 71 and the second coil 72 is used as an excitation coil, and the other is used as a detection coil. The excitation coil generates eddy currents on the surface of the inspection area, including the welded portion. Cracks or thinning in the welded portion cause disturbances in the eddy currents. The detection coil detects these disturbances. Figure 6 shows an example in which the second coil 72 serves as the excitation coil and the first coil 71 serves as the detection coil. As indicated by the arrows in the figure, the eddy currents form multiple arcs extending from one end to the other end along the first axis A1 on the surface of the inspection area. This improves the detection accuracy for flaws and cracks extending in a direction that crosses the eddy currents. However, this reduces the detection accuracy for flaws and cracks along the first axis A1, as indicated by the dashed line 100 in Figure 6.

[0027] In the self-induction self-comparison method, the first coil 71 and the second coil 72 each function as both an excitation coil and a detection coil. In other words, this method detects disturbances in the eddy currents they generate. In this case, as shown in FIG. 7, the eddy currents flow in multiple arcs from one end to the other in a direction that intersects the first axis A1 and the second axis A2 at a 45-degree angle, as viewed from the third axis A3. This allows for accurate detection of flaws and cracks extending in the first axis A1 or second axis A2 directions, which were difficult to detect using the above-mentioned mutual induction standard comparison method.

[0028] (Action and effect) Next, an example of how to use the above-described eddy current flaw detector 1 and probe array will be described. When using the eddy current flaw detector 1, first, an AC current is supplied to each coil module 20 of the array probe 10 by the power supply unit 40. Then, any one of the two operating modes described above is appropriately selected by the switch unit 30. In this state, the array probe 10 is caused to scan along the surface of a pipe, weld, or the like. When each coil module 20 detects a defect, the flaw detector main body 50 identifies the location of the defect and confirms its properties, such as depth and length. More specifically, the location is identified by an encoder within the flaw detector main body 50, and properties such as depth and length are obtained by analysis.

[0029] Conventionally, the cross coil 21 has been manufactured by alternately winding the excitation coil and the detection coil around the spool. This means that the process of winding the excitation coil and then winding the detection coil in a direction that crosses the excitation coil must be repeated.

[0030] However, when manufacturing the cross coil 21 using the above-mentioned bobbin, it is difficult to automate the process, which leads to problems such as increased manufacturing costs and a long manufacturing period. In particular, when manufacturing a probe for eddy current flaw detection that requires a large number of cross coils 21, the delivery time for the cross coils 21 becomes a significant bottleneck. Therefore, the present embodiment employs the above-mentioned configurations.

[0031] According to the above configuration, the first coil 71 is inserted inside the second coil 72 to assemble the cross coil 21, and then the cross coil 21 is inserted into the first housing portion 81 and the second housing portion 82 of the case 22, thereby easily manufacturing the coil module 20. In addition, coils with a simple annular shape can be manufactured in large quantities at low cost and in a short delivery time through automation. This eliminates the need for the conventional process of alternately winding the wire around a bobbin. As a result, it is possible to achieve both a significant reduction in manufacturing costs and a shortened manufacturing time.

[0032] Furthermore, with the above configuration, the first housing portion 81 and the second housing portion 82 are open toward one side in the direction of the third axis A3, so that the cross coil 21 can be easily inserted into the case 22 through the opening. This significantly simplifies the work procedure and reduces the number of steps required for assembly. Also, simply by inserting the cross coil 21 into the case 22, the shape and posture of the cross coil 21 can be stably maintained. This reduces the possibility of the cross coil 21 being damaged, deformed, or its posture being changed due to, for example, an external force.

[0033] In addition, with the above configuration, the second housing portion 82 is recessed by the height of the second coil 72 protruding outward. That is, the second bottom surface 83 is recessed in the direction of the third axis A3 relative to the first bottom surface 84. As a result, when the cross coil 21 is housed in the case 22, the second coil 72 is surrounded by the second bottom surface 83 and a pair of side surfaces 85 that sandwich the second bottom surface 83. This defines the position of the second coil 72, reducing the possibility of the second coil 72 becoming loose or shifting in position. As a result, noise caused by looseness of the second coil 72 during flaw detection can be significantly reduced. This improves the accuracy and efficiency of flaw detection.

[0034] Furthermore, with the above configuration, since the first coil 71 and the second coil 72 each have a rectangular ring shape, the area (facing area) of the region adjacent to the object to be detected, such as a pipe or a weld, can be increased compared to when the coils are, for example, circular. This allows eddy currents to be generated over a wider range and disturbances of the eddy currents to be detected over a wider range. On the other hand, when each coil has a ring shape, the region adjacent to the pipe or the like is narrowed. As a result, the region where eddy currents are generated is limited, and the strength of the eddy currents is reduced, resulting in poor detectability for flaws and thinning defects. With the above configuration, these disadvantages are eliminated, thereby significantly improving the detection accuracy when the coil module 20 is applied to a flaw detection device.

[0035] Furthermore, according to the above configuration, the array probe 10 has an elastically deformable holding member 11. In other words, the holding member 11 is flexible. That is, by pressing the holding member 11 against a curved surface such as a pipe, the holding member 11 is elastically deformed, and the entire array probe 10 can be brought into close contact with the curved surface. By performing scanning with the coil module 20 in this state, it is possible to prevent the coil from floating not only on the surface of the pipe, but also in areas where the shape changes, such as the surface of an elbow or weld of the pipe, thereby ensuring defect detectability.

[0036] In addition, with the above configuration, the coil modules 20 are accommodated one by one in each of the accommodation sections 12 formed in the holding member 11. As a result, if, for example, any of the coil modules 20 becomes defective, only the defective coil module 20 can be removed from the accommodation section 12 and immediately replaced with a new one. This makes it possible to reduce the maintenance costs and operating costs of the array probe 10.

[0037] Furthermore, according to the above configuration, the positions of the coil modules 20 in the first arrangement direction D1 are different between the probe rows 60, so that when viewed from the second arrangement direction D2, the coil modules 20 overlap each other with no gaps. As a result, when the array probe 10 is moved in the second arrangement direction D2, a wider range in the first arrangement direction D1 is covered by each coil module 20. This makes it possible to scan pipes, welds, etc. evenly over a wider range with high inspection density.

[0038] Furthermore, with the above configuration, the end faces 91 facing both sides in the first axis A1 direction and the end faces 91 facing both sides in the second axis A2 direction are each chamfered. In other words, the case 22 is octagonal when viewed from the third axis A3 direction. This prevents the corners of the case 22 from interfering with each other when the holding member 11 of the array probe 10 is elastically deformed. In particular, since the corners do not interfere with each other when the array probe 10 itself is elastically deformed in a twisting manner, the shape change of the array probe 10 is less likely to be hindered. This further improves the ability of the array probe 10 to conform to curved surfaces. This allows the array probe 10 to be adapted to various curved surface shapes, improving the versatility of the array probe 10.

[0039] Furthermore, according to the above configuration, the eddy current flaw detector 1 is provided with the switch unit 30, which allows switching between the operation modes of the first coil 71 and the second coil 72. This allows the direction of eddy current flow to be changed without changing the posture of the first coil 71 and the second coil 72. In other words, it is possible to generate eddy currents in various directions using the same array probe 10. By changing the direction of eddy current flow depending on the direction of defects (cracks or thinning) in pipes, welds, etc., it is possible to perform more precise and highly accurate scanning and flaw detection in response to a variety of defects.

[0040] (Other embodiments) The above describes in detail the embodiments of the present disclosure with reference to the drawings, but the specific configuration is not limited to this embodiment, and design changes and the like are also included within the scope that does not deviate from the gist of the present disclosure.

[0041] For example, in the above embodiment, an example has been described in which the first coil 71 and the second coil 72 of the cross coil 21 each have a rectangular ring shape. However, the shape of the cross coil 21 is not limited to the above. As a first modified example, as shown in FIG. 8, the first coil 71 can be formed into a circular ring shape, and the second coil 72 can be formed into a rectangular ring shape. Furthermore, as a second modified example, as shown in FIG. 9, both the first coil 71 and the second coil 72 can be formed into a circular ring shape. While either case is applicable to the cross coil 21, the shape described in the above embodiment is most advantageous in terms of the accuracy of detecting defective parts.

[0042] <Additional Notes> The coil module 20, the array probe 10, and the eddy current flaw detector 1 described in each embodiment can be understood, for example, as follows.

[0043] (1) The coil module 20 according to the first aspect includes a cross coil 21 having a first coil 71 having an annular shape centered on a first axis A1, and a second coil 72 having an annular shape centered on a second axis A2 intersecting the first axis A1 and covering a portion of the outer periphery of the first coil 71, and a case 22 having a first accommodating section 81 extending in the direction of the first axis A1 to accommodate the first coil 71, and a second accommodating section 82 extending in the direction of the second axis A2 to accommodate the second coil 72.

[0044] According to the above configuration, the first coil 71 is inserted inside the second coil 72 to assemble the cross coil 21, and then the cross coil 21 is inserted into the first housing portion 81 and the second housing portion 82 of the case 22, respectively, thereby making it possible to easily manufacture the coil module 20. This makes it possible to achieve both reduced manufacturing costs and shorter delivery times.

[0045] (2) The coil module 20 according to the second aspect is the coil module 20 of (1), in which the first accommodating section 81 and the second accommodating section 82 are open toward one side in the direction of a third axis A3 that is perpendicular to the first axis A1 and the second axis A2.

[0046] According to the above configuration, the first accommodating portion 81 and the second accommodating portion 82 are open toward one side in the direction of the third axis A3, and therefore the cross coil 21 can be easily inserted into the case 22 through the openings. This reduces the number of steps required for assembly.

[0047] (3) The coil module 20 according to the third aspect is the coil module 20 of (2), in which the bottom surface of the second accommodating section 82 is recessed in the direction of the third axis A3 from the bottom surface of the first accommodating section 81 by an amount equal to the height of the second coil 72 in the direction of the third axis A3.

[0048] According to the above configuration, the second accommodating section 82 is recessed by the height of the second coil 72 protruding outward, thereby reducing the possibility of rattle or misalignment of the second coil 72 when the cross coil 21 is accommodated within the case 22.

[0049] (4) The coil module 20 according to the fourth aspect is a coil module 20 according to any one of aspects (1) to (3), in which the first coil 71 forms a rectangular ring shape centered on the first axis A1, and the second coil 72 forms a rectangular ring shape centered on the second axis A2.

[0050] According to the above configuration, since the first coil 71 and the second coil 72 each have a rectangular ring shape, the area (facing area) of the proximity region to the object to be detected, such as a pipe or a welded joint, can be increased compared to when the coils have a circular ring shape, for example. As a result, the accuracy of flaw detection can be improved when the coil module 20 is applied to a flaw detection device.

[0051] (5) The array probe 10 according to the fifth aspect includes a plurality of coil modules 20 according to any one of aspects (1) to (4) arranged in a first arrangement direction D1 that intersects the first axis A1 and the second axis A2 and extends within the same plane, and a holding member 11 that supports the plurality of coil modules 20 and is formed of an elastically deformable material.

[0052] According to the above configuration, by pressing the holding member 11 against a curved surface such as a pipe or a welded portion, the holding member 11 is elastically deformed, and the entire array probe 10 can be brought into close contact with the curved surface. By performing scanning with the coil module 20 in this state, it becomes possible to perform flaw detection with higher accuracy.

[0053] (6) The array probe 10 according to a sixth aspect is the array probe 10 of (5), wherein the holding member 11 has a plurality of housing portions 12 in which the coil modules 20 are housed.

[0054] According to the above configuration, since each of the coil modules 20 is accommodated in each of the accommodation sections 12, if, for example, a defect occurs in one of the coil modules 20, only the defective coil module 20 can be removed from the accommodation section 12 and immediately replaced with a new one. This makes it possible to reduce the maintenance costs and operating costs of the array probe 10.

[0055] (7) The array probe 10 according to the seventh aspect is the array probe 10 of (5) or (6), which has a plurality of the coil modules 20 and the holding member 11, and also has a plurality of probe rows 60 arranged in a second arrangement direction D2 perpendicular to the first arrangement direction D1, and the positions of the coil modules 20 in the first arrangement direction D1 are different between a pair of the probe rows 60 adjacent to each other in the second arrangement direction D2.

[0056] According to the above configuration, the positions of the coil modules 20 in the first arrangement direction D1 are different between the probe rows 60, so when viewed from the second arrangement direction D2, the coil modules 20 overlap each other with no gaps between them. This allows the coil modules 20 to scan welds, pipes, etc. over a wider range in the first arrangement direction D1 without floating.

[0057] (8) The array probe 10 according to the eighth aspect is the array probe 10 according to any one of the aspects (5) to (7), in which the end faces 91 of the case 22 facing both sides in the direction of the first axis A1 extend within a plane intersecting the first axis A1, and the end faces 91 facing both sides in the direction of the second axis A2 extend within a plane intersecting the second axis A2.

[0058] According to the above configuration, the end faces 91 facing both sides in the first axis A1 direction and the end faces 91 facing both sides in the second axis A2 direction are each chamfered. In other words, the case 22 is octagonal when viewed from the third axis A3 direction. This prevents the corners of the case 22 from interfering with each other when the holding member 11 of the array probe 10 is elastically deformed. This further improves the ability of the array probe 10 to conform to curved surfaces.

[0059] (9) The eddy current flaw detection device 1 according to the ninth aspect comprises an array probe 10 according to any one of aspects (5) to (8), a power supply unit 40 that supplies AC current to each of the first coil 71 and the second coil 72, and a switch unit 30 that switches the supply state of the AC current between a mutual induction standard comparison method in which one of the first coil 71 and the second coil 72 is operated as an excitation coil that generates eddy currents and the other is operated as a detection coil that detects flaws by disturbances in the eddy currents, and a self-induction self-comparison method in which each of the first coil 71 and the second coil 72 is operated as an excitation coil that generates eddy currents and as a detection coil that detects flaws by disturbances in the eddy currents.

[0060] According to the above configuration, by providing the switch unit 30, it is possible to switch the operation mode of each of the first coil 71 and the second coil 72. This makes it possible to change the direction of the eddy current flow without changing the posture of the first coil 71 and the second coil 72. By changing the direction of the eddy current flow according to the direction of a defect (crack or thinning) in a pipe, weld, or the like, it becomes possible to perform scanning and flaw detection in response to a variety of defect locations. [Explanation of symbols]

[0061] 1...Eddy current flaw detection device 10...Array probe 11...Holding member 12...Storage section 20...Coil module 21...Cross coil 22…Case 30...Switch section 40...Power supply section 50…Flaw detection device body 60...probe row 71...First coil 72...Second coil 81...First storage area 82...Second storage area 83…Second bottom surface 84…First bottom surface 85...Side 91...End face 100...dashed line A1…first axis line A2…Second axis A3…Third axis D1: First arrangement direction D2: Second arrangement direction

Claims

1. a cross coil including a first coil having an annular shape centered on a first axis line, and a second coil having an annular shape centered on a second axis line intersecting the first axis line and covering a part of the outer periphery of the first coil; a case including a first housing portion extending in the first axial direction and housing the first coil, and a second housing portion extending in the second axial direction and housing the second coil; A coil module comprising:

2. The coil module according to claim 1 , wherein the first accommodating portion and the second accommodating portion are open toward one side in a third axis direction perpendicular to the first axis and the second axis.

3. The coil module according to claim 2, wherein the bottom surface of the second accommodating section is recessed in the third axial direction from the bottom surface of the first accommodating section by an amount equal to the height of the second coil in the third axial direction.

4. The coil module according to any one of claims 1 to 3, wherein the first coil has a rectangular ring shape centered on the first axis, and the second coil has a rectangular ring shape centered on the second axis.

5. a plurality of coil modules according to claim 1 arranged in a first arrangement direction that intersects the first axis and the second axis and extends in the same plane; a holding member that supports the plurality of coil modules and is made of an elastically deformable material; An array probe comprising:

6. The array probe according to claim 5 , wherein the holding member has a plurality of housing portions in which the coil modules are housed.

7. a plurality of probe rows including a plurality of the coil modules and the holding member, and arranged in a second arrangement direction perpendicular to the first arrangement direction; The array probe according to claim 5 or 6, wherein the positions of the coil modules in the first arrangement direction are different between a pair of the probe rows adjacent to each other in the second arrangement direction.

8. 7. An array probe as described in claim 5 or 6, wherein the end faces of the case facing both sides in the first axis direction extend in a plane intersecting the first axis, and the end faces of the case facing both sides in the second axis direction extend in a plane intersecting the second axis.

9. The array probe according to claim 5 or 6; a power supply unit that supplies AC current to each of the first coil and the second coil; a switch unit that switches the supply state of the AC current between a mutual induction standard comparison method in which one of the first coil and the second coil is operated as an excitation coil that generates an eddy current and the other is operated as a detection coil that detects flaws by disturbances in the eddy current, and a self-induction self-comparison method in which each of the first coil and the second coil is operated as an excitation coil that generates an eddy current and as a detection coil that detects flaws by disturbances in the eddy current; An eddy current flaw detection device comprising:

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