JP7064086B2 - Eddy current flaw detector - Google Patents

Description

The present disclosure relates to an eddy current flaw detector.

Heat transfer tubes provided in conventional boilers and HRSGs (exhaust heat recovery steam generators for gas turbines) may cause troubles such as wall thinning and cracks on the inner surface thereof due to, for example, oxygen corrosion and alkaline corrosion. Therefore, in order to prevent such troubles in advance, an eddy current flaw detection test (ECT: Eddy Current Testing) is performed on the heat transfer tube.

Patent Document 1 describes an example of a technique for performing such an eddy current flaw detection inspection. Specifically, by using a function created in advance for the measurement data acquired from the probe to determine the type and degree of defects inside the pipe, even non-skilled inspectors can determine the internal state of the pipe. The technology that can judge is disclosed.

By the way, in order to perform an eddy current flaw detection inspection, it is necessary to transport an eddy current sensor such as a probe that can detect changes in the eddy current through the inside of the heat transfer tube to the vicinity of the inner surface of the heat transfer tube to be inspected. .. At this time, it is necessary to align the position of the eddy current sensor so that the position of the eddy current sensor does not shift in the radial direction of the heat transfer tube.

In this regard, for example, in the eddy current flaw detector described in Patent Document 2, a support shaft such as a shaft to which an eddy current sensor is attached is pushed into the inside of a pipe by human power or a machine (a pusher type transfer device is used). The eddy current sensor is transported to the vicinity of the inner surface of the pipe to be inspected by using (using) or using the water flow sent out inside the pipe (using a hydraulic transfer device). Then, the position of the eddy current sensor is aligned so that the position of the eddy current sensor does not shift in the radial direction of the pipe by the bristling type centering jig provided with the bristles that spread radially.

Japanese Unexamined Patent Publication No. 5-321787 Japanese Unexamined Patent Publication No. 2014-98630

However, the bristle brush type centering jig as described in Patent Document 2 has a large frictional resistance to the inner surface of the pipe by the bristle brush, especially when the eddy current sensor is transported by the pusher type transport device. This is clarified by the findings of the present inventors. If the frictional resistance is large, the passage of the probe through the pipe may be reduced and the total length of the pipe may not be inspected.

At least some embodiments of the present invention have been made in view of the above findings, and the alignment jig in which the frictional resistance to the inner surface of the pipe is suppressed as compared with the conventional bristle brush type alignment jig. It is an object of the present invention to provide an eddy current flaw detector.

(1) The eddy current flaw detector according to at least one embodiment of the present invention is attached to a flexible tube that can be inserted inside a pipe and the flexible tube, and at the same time, generates an eddy current on the inner surface of the pipe to generate the eddy current. A sensor that detects changes in electric current, a main body portion having a fitting hole into which the flexible tube is inserted, and a plurality of elastic portions formed of an elastic material extending radially outward from the main body portion. It is provided with at least one centering jig including a plurality of elastic portions having a contact surface in contact with the inner surface of the pipe.

According to the configuration of (1) above, when the flexible tube is inserted into the inside of the pipe and the sensor is conveyed to the vicinity of the inner surface of the pipe to be inspected, the cross-sectional shape inside the pipe changes (a place where the cross-sectional shape inside the pipe changes. For example, if there is a place where deposits are attached to the inner surface of the pipe or a place where the inner surface of the pipe is deformed by welding back waves), multiple elastic parts included in the centering jig are radially inward. Elastically deforms toward. Therefore, the flexible tube can be smoothly inserted into the inside of the pipe, and the sensor can be conveyed to the vicinity of the inner surface of the pipe to be inspected.
Further, when the flexible tube is inserted into the inside of the pipe and the sensor is conveyed to the vicinity of the inner surface of the pipe to be inspected, the inner surface of the pipe and the contact surface of a plurality of elastic parts included in the alignment jig are contacted. It is transported in a state of contact (surface contact). Therefore, unlike the conventional bristle brush type centering jig, the jig is conveyed in a state of surface contact rather than line contact, so that frictional resistance to the inner surface of the pipe can be suppressed.

(2) In some embodiments, in the configuration of (1) above, the at least one alignment jig is a tip side alignment jig mounted on the tip side of the flexible tube with respect to the sensor. , A rear end side alignment jig mounted on the rear end side of the flexible tube with respect to the sensor.

According to the configuration (2) above, when the sensor attached to the flexible tube is transported to the vicinity of the inner surface of the pipe to be inspected, the tip side of the flexible tube is aligned with the tip side of the sensor. Since the jig is attached to the rear end side alignment jig on the rear end side of the flexible tube with respect to the sensor, the alignment property of the alignment jig can be improved.

(3) In some embodiments, in the configuration of (2) above, the elastic portion comprises a leaf spring extending diagonally outward from the main body portion in the radial direction.

The leaf spring receives the reaction force from the inner surface of the pipe more reliably than the conventional bristle brush type centering jig. Therefore, according to the configuration of (3) above, when the flexible tube is inserted into the inside of the pipe and the sensor is conveyed to the vicinity of the inner surface of the pipe to be inspected, the position of the sensor does not shift in the radial direction of the pipe. The position of the sensor can be more appropriately aligned. Therefore, for example, a pusher-type transport device can be used to transport the sensor to the vicinity of the inner surface of the pipe to be inspected, and perform an eddy current flaw detection inspection to perform a wall thinning inspection of the pipe.

(4) In some embodiments, in the configuration of (3) above, a sliding contact surface is formed at the tip of the leaf spring so as to be in sliding contact with the inner surface of the pipe, and the sliding contact surface is in contact with the inner surface. Make up a face.

According to the configuration of (4) above, by sliding the sliding contact surface with respect to the inner surface of the pipe, the flexible tube is smoothly inserted into the pipe, and the sensor is placed near the inner surface of the pipe to be inspected. Can be transported.

(5) In some embodiments, in the configuration of (3) above, a rotating body that can rotate in contact with the inner surface of the pipe is attached to the tip of the leaf spring, and the rotating body is attached. The outer peripheral surface of the above constitutes the contact surface.

According to the configuration of (5) above, the rotating body rotates in contact with the inner surface of the pipe, so that the flexible tube is smoothly inserted into the pipe and the sensor is placed near the inner surface of the pipe to be inspected. Can be transported.

(6) In some embodiments, in any one of the above configurations (3) to (5), the leaf spring of the tip side alignment jig faces the sensor in the longitudinal direction of the flexible tube. The leaf spring of the rear end side alignment jig extends toward the sensor in the longitudinal direction of the flexible tube.

By increasing the length from the front end side alignment jig to the rear end side alignment jig in the longitudinal direction of the flexible tube, it is sandwiched between the front end side alignment jig and the rear end side alignment jig. The portion of the flexible tube that has been removed passes through, for example, the bend portion of the pipe, and the sensor can be easily transported to the vicinity of the inner surface of the pipe to be inspected. On the other hand, by shortening the length from the contact surface of the front end side alignment jig to the sensor and the length from the contact surface of the rear end side alignment jig to the sensor, the alignment by the alignment jig is shortened. It can enhance the sex. According to the configuration of (6) above, the contact surface of the front end side alignment jig and the rear end side alignment jig are maintained while maintaining the length from the front end side alignment jig to the rear end side alignment jig. The contact surface of the jig is configured to approach the sensor. Therefore, it is possible to improve the alignment property by the alignment jig while facilitating the transfer of the sensor to the vicinity of the inner surface of the pipe to be inspected.

(7) In some embodiments, in any one of the configurations (1) to (6) above, the contact surface is formed of a material having better wear resistance than other parts of the elastic portion. ..

According to the configuration of (7) above, it is possible to prevent the contact surface from being damaged by contact with the inner surface of the pipe.

(8) In some embodiments, in any one of the above configurations (1) to (7), the flexible tube is a plurality of spherical surfaces mounted at intervals along the outer peripheral surface of the flexible tube. When the body is provided, the diameter of the pipe is L1, and the interval is L2, 3 ≦ L2 / L1 ≦ 6.

According to the configuration of (8) above, when the flexible tube is inserted into the inside of the pipe and the sensor is conveyed to the vicinity of the inner surface of the pipe to be inspected, the outer peripheral surface of the flexible tube is formed by a plurality of spherical bodies. It is possible to prevent the contact with the inner surface.
Further, when the size of the diameter of the flexible tube is L1 and the interval is L2, by setting 3 ≦ L2 / L1 ≦ 6, the transfer conditions of the pusher type transfer device (the flexible tube having a plurality of spherical bodies is piped). When inserting the flexible tube inside the pipe and transporting the sensor to the vicinity of the inner surface of the pipe to be inspected, the flexible tube sits inside the pipe while satisfying the mechanical restrictions for inserting it inside the pipe. It is possible to prevent it from yielding.

(9) In some embodiments, in any one of the above configurations (1) to (8), the flexible tube includes a tip guide portion provided at the tip portion of the flexible tube, and the tip guide portion is provided. Includes a guide portion having a spherical shape.

According to the configuration (9) above, when the flexible tube passes through a portion where the cross-sectional shape of the pipe changes (for example, the bend portion of the pipe), the tip guide portion comes into contact with the inner surface of the bend portion. Induce the flexible tube. Therefore, the flexible tube can be smoothly inserted into the inside of the pipe, and the sensor can be conveyed to the vicinity of the inner surface of the pipe to be inspected.

(10) In some embodiments, in any one of the above (1) to (9) configurations, the tip of the flexible tube is formed of a material that is more flexible than the other parts of the flexible tube. Will be done.

According to the configuration of (10) above, when the flexible tube passes through a portion where the cross-sectional shape of the pipe changes (for example, the bend portion of the pipe), the tip portion of the flexible tube corresponds to the cross-sectional shape of the bend portion. The flexible tube is guided by bending before other parts of the flexible tube. Therefore, the flexible tube can be smoothly inserted into the inside of the pipe, and the sensor can be conveyed to the vicinity of the inner surface of the pipe to be inspected.

According to at least one embodiment of the present invention, there is provided an eddy current flaw detector provided with a alignment jig in which frictional resistance to the inner surface of a pipe is suppressed as compared with a conventional bristle brush type alignment jig. Can be done.

It is a schematic block diagram of the eddy current flaw detector which concerns on one Embodiment of this invention. It is a schematic block diagram which shows the alignment jig of the eddy current flaw detector which concerns on one Embodiment of this invention. It is explanatory drawing for demonstrating the alignment jig of the eddy current flaw detector which concerns on one Embodiment of this invention. FIG. 3 is a cross-sectional view of the cross section taken along the line AA of FIG. 3A as viewed toward the tip end side. It is explanatory drawing for demonstrating the alignment jig of the eddy current flaw detector which concerns on one Embodiment of this invention. It is sectional drawing which looked at the BB cross section of FIG. 4A toward the tip side. It is a schematic block diagram which shows the alignment jig of the eddy current flaw detector 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 as embodiments or shown in the drawings are not intended to limit the scope of the present invention to this, but are merely explanatory examples. not.
For example, expressions that represent relative or absolute arrangements such as "in one direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric" or "coaxial" are exact. Not only does it represent such an arrangement, but it also represents a tolerance or a state of relative displacement at an angle or distance to the extent that the same function can be obtained.
Further, for example, the expression representing a shape such as a square shape or a cylindrical shape not only represents a shape such as a square shape or a cylindrical shape in a geometrically strict sense, but also has an uneven portion or a concave portion within a range where the same effect can be obtained. The shape including the chamfered portion and the like shall also be represented.
On the other hand, the expressions "equipped", "equipped", "equipped", "included", or "have" one component are not exclusive expressions excluding the existence of other components.

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, the eddy current flaw detector 1 according to the embodiment of the present invention includes a flexible tube 2, a sensor 4, and a centering jig 6.

As shown in FIG. 1, the flexible tube 2 is configured to be insertable inside the pipe 100 to be inspected. The outer diameter of such a flexible tube 2 is smaller than the inner diameter of the pipe 100. The flexible tube 2 is, for example, a long member made of metal, resin, or the like, and is configured to be bendable over the entire length according to the shape of the pipe line of the pipe 100.

Further, the flexible tube 2 is connected to a transfer device (not shown) arranged outside the pipe 100 via the rear end portion of the flexible tube 2. This transfer device is, for example, a pusher type transfer device that pushes the flexible tube 2 into the inside of the pipe 100 by human power or a machine. By pushing the flexible tube 2 into the inside of the pipe 100 by this pusher type transfer device, the flexible tube 2 is inserted into the inside of the pipe 100, and the sensor 4 is conveyed to the vicinity of the inner surface 102 of the pipe 100 to be inspected. Can be done.
It should be noted that the transfer device can be applied to other than the pusher type transfer device. For example, the transfer device may be a hydraulic transfer device that sends a water flow into the inside of the pipe 100.

As shown in FIG. 1, the sensor 4 is attached to the outer peripheral surface 2a of the flexible tube 2.
In some embodiments, the flexible tube 2 is divided before and after the sensor 4, and the sensor 4 can be attached to the flexible tube 2 by being sandwiched between the divided flexible tubes 2. good.

Further, as shown in FIG. 1, the sensor 4 includes a plurality of array coils 8 arranged along the circumferential direction and the axial direction of the flexible tube 2. The plurality of array coils 8 are configured so that the sensor 4 generates an eddy current over the entire circumference of the inner surface 102 of the pipe 100 and can detect the change in the generated eddy current.

FIG. 2 is a schematic configuration diagram showing a centering jig of an eddy current flaw detector according to an embodiment of the present invention. FIG. 3A is an explanatory diagram for explaining the alignment jig of the eddy current flaw detector according to the embodiment of the present invention. FIG. 3B is a cross-sectional view taken along the line AA of FIG. 3A as viewed toward the tip side. FIG. 4A is an explanatory diagram for explaining the alignment jig of the eddy current flaw detector according to the embodiment of the present invention. FIG. 4B is a cross-sectional view taken along the line BB of FIG. 4A as viewed toward the tip side. FIG. 5 is a schematic configuration diagram showing a centering jig of an eddy current flaw detector according to an embodiment of the present invention.

As shown in FIG. 2, the centering jig 6 includes a main body portion 10 and a plurality of elastic portions 12. The main body 10 has a fitting hole 13 into which the flexible tube 2 is fitted. In the embodiment shown in FIG. 2, after the flexible tube 2 is inserted into the fitting hole 13 of the main body portion 10, the screw 14 is inserted into the screw hole (not shown) formed in the pipe 100 and the main body portion 10. Therefore, the alignment jig 6 is attached to the flexible tube 2. Further, a gap 19 is formed between the plurality of elastic portions 12 and the outer peripheral surface 2a of the flexible tube 2.

The plurality of elastic portions 12 are formed of an elastic material such as a synthetic resin. Then, as shown in FIGS. 3B and 4B, these plurality of elastic portions 12 extend radially outward from the main body portion 10. The plurality of elastic portions 12 have a contact surface 18 that comes into contact with the inner surface 102 of the pipe 100. In the embodiment shown in FIGS. 3B and 4B, the six elastic portions 12 are arranged at equal intervals along the circumferential direction of the main body portion 10 and are arranged so as to face each other with the main body portion 10 interposed therebetween. There is. Each elastic portion 12 extends radially outward from the main body portion 10.
In some embodiments, as shown in FIGS. 3B and 4B, when the contact surface 18 is viewed in cross section, the contact surface 18 is configured to be curved so as to be along the inner surface 102 of the pipe 100 to be inspected. You may.

In some embodiments, as shown in FIG. 5, the elastic portion 12 is connected to a spring 27 extending radially outward from the main body portion 10 and one end of the spring 27 on the radial outer side. Also included is a contact body 28 having a contact surface 18 in contact with the inner surface 102 of the pipe 100.

According to one embodiment of the present invention, when the flexible tube 2 is inserted into the pipe 100 and the sensor 4 is conveyed to the vicinity of the inner surface 102 of the pipe 100 to be inspected, the inside of the pipe 100 is conveyed. If there is a place where the cross-sectional shape changes (for example, a place where deposits are attached to the inner surface 102 of the pipe 100 or a place where the inner surface 102 of the pipe 100 is deformed by the back wave of welding), the alignment is cured. The plurality of elastic portions 12 included in the tool 6 are elastically deformed inward in the radial direction. Therefore, the flexible tube 2 can be smoothly inserted into the pipe 100, and the sensor 4 can be conveyed to the vicinity of the inner surface 102 of the pipe 100 to be inspected.
Further, when the flexible tube 2 is inserted into the pipe 100 and the sensor 4 is conveyed to the vicinity of the inner surface 102 of the pipe 100 to be inspected, a plurality of components included in the inner surface 102 of the pipe 100 and the centering jig 6 are included. It is conveyed in a state where it is in contact with the contact surface 18 of the elastic portion 12 of the above (surface contact). Therefore, unlike the conventional bristle brush type centering jig, the pipes are transported in a state of surface contact rather than line contact, so that frictional resistance to the inner surface 102 of the pipe 100 can be suppressed.

Further, in some embodiments, as shown in FIG. 2, at least one alignment jig 6 is a tip side alignment jig 6a (6) mounted on the tip side of the flexible tube 2 with respect to the sensor 4. ) And the rear end side alignment jig 6b (6) mounted on the rear end side of the flexible tube 2 with respect to the sensor 4.

According to such a configuration, when the sensor 4 attached to the flexible tube 2 is conveyed to the vicinity of the inner surface 102 of the pipe 100 to be inspected, the sensor 4 is placed on the tip side of the flexible tube 2 with respect to the sensor 4. Since the front end side alignment jig 6a is mounted on the rear end side alignment jig 6b on the rear end side of the flexible tube 2 with respect to the sensor 4, the alignment performance by the alignment jig 6 is improved. Can be done.

Further, in some embodiments, as shown in FIGS. 3A and 4A, the elastic portion 12 is composed of a leaf spring 121 (12) extending diagonally outward from the main body portion 10 in the radial direction.

The leaf spring 121 more reliably receives the reaction force from the inner surface 102 of the pipe 100 as compared with the conventional bristle brush type centering jig. Therefore, according to such a configuration, when the flexible tube 2 is inserted into the pipe 100 and the sensor 4 is conveyed to the vicinity of the inner surface 102 of the pipe 100 to be inspected, the position of the sensor 4 is the position of the pipe 100. The position of the sensor 4 can be more appropriately aligned so as not to shift in the radial direction. Therefore, for example, using the pusher type transport device described above, the sensor 4 can be transported to the vicinity of the inner surface 102 of the pipe 100 to be inspected, and the wall thinning inspection of the pipe 100 can be performed by performing an eddy current flaw detection inspection. can.

Further, according to such a configuration, when performing an eddy current flaw detection inspection on a pipe 100 having a relatively small number of bent portions (1 to 2 locations) as provided in the HRSG, the pusher type transfer device described above is used. Since the sensor 4 can be transported by using the above-mentioned, it is possible to reduce the labor (such as injecting water into the inside of the pipe 100) as in the case of transporting the sensor 4 by using the above-mentioned hydraulic transport device.

Further, in some embodiments, as shown in FIGS. 3A and 3B, the tip portion 123 of the leaf spring 121 is formed with a sliding contact surface 181 (18) that is in sliding contact with the inner surface 102 of the pipe 100. The sliding contact surface 181 constitutes the above-mentioned contact surface 18.

According to such a configuration, by sliding the sliding contact surface 181 with respect to the inner surface 102 of the pipe 100, the flexible tube 2 is smoothly inserted into the pipe 100, and the sensor 4 is the pipe 100 to be inspected. It can be transported to the vicinity of the inner surface 102 of the.

The sliding contact surface 181 is formed of, for example, a resin material such as PTFE, so that the frictional resistance acting on the sliding contact surface 181 when the sliding contact surface 181 is slid with respect to the inner surface 102 of the pipe 100. Becomes smaller. Therefore, the flexible tube 2 can be more smoothly inserted into the pipe 100, and the sensor 4 can be conveyed to the vicinity of the inner surface 102 of the pipe 100 to be inspected.

Further, in some embodiments, as shown in FIG. 3A, the leaf spring 121 of the alignment jig 6 is a first inclined surface 24 extending inclined from one end 18a of the contact surface 18 toward the sensor 4. And a second inclined surface 26 extending from the other end 18b on the side farther from the sensor 4 than one end 18a of the contact surface 18 so as to be inclined toward the side opposite to the direction toward the sensor 4.

According to such a configuration, when the flexible tube 2 to which the alignment jig 6 is attached is inserted into the inside of the pipe 100 or pulled out from the inside of the pipe 100, for example, the inner surface 102 of the pipe 100 The first inclined surface 24 and the second inclined surface 26 guide the deposit to the contact surface 18 even if the deposit is attached to the surface. Then, by sliding the contact surface 18 with respect to the induced deposit, the flexible tube 2 to which the alignment jig 6 is attached can be smoothly inserted into the pipe 100 without being hindered by the deposit. It can be inserted or smoothly pulled out from the inside of the pipe 100.

Further, in some embodiments, as shown in FIGS. 4A and 4B, a rotating body 22 that can rotate in contact with the inner surface 102 of the pipe 100 is attached to the tip portion 123 of the leaf spring 121. .. The outer peripheral surface 182 of the rotating body 22 constitutes the above-mentioned contact surface 18.

In the embodiment shown in FIG. 4B, the tip portion 123 of the leaf spring 121 includes two support portions 125, 125 extending radially outward. The rotating body 22 is rotatably attached to a support shaft 127 connecting one support portion 125 and the other support portion 125.

According to such a configuration, the rotating body 22 rotates in contact with the inner surface 102 of the pipe 100, so that the flexible tube 2 is smoothly inserted into the pipe 100 and the sensor 4 is the pipe 100 to be inspected. It can be transported to the vicinity of the inner surface 102 of the.

Further, in some embodiments, as shown in FIG. 2, the elastic portion 12 of the tip-side alignment jig 6a extends toward the sensor 4 in the longitudinal direction of the flexible tube 2. The elastic portion 12 of the rear end side alignment jig 6b extends toward the sensor 4 in the longitudinal direction of the flexible tube 2. As described above, the elastic portion 12 may be a leaf spring 121.

By increasing the length from the front end side alignment jig 6a to the rear end side alignment jig 6b in the longitudinal direction of the flexible tube 2, the front end side alignment jig 6a and the rear end side alignment jig 6b The portion of the flexible tube 2 sandwiched between the two passes through, for example, the bend portion (not shown) of the pipe 100, and the sensor 4 can be easily transported to the vicinity of the inner surface 102 of the pipe 100 to be inspected. .. On the other hand, by shortening the length from the contact surface 18 of the front end side alignment jig 6a to the sensor 4 and the length from the contact surface 18 of the rear end side alignment jig 6b to the sensor 4, the adjustment is performed. The alignment property of the core jig 6 can be improved.

According to such a configuration, the contact surface 18 of the front end side alignment jig 6a and the rear end side adjustment are maintained while maintaining the length from the front end side alignment jig 6a to the rear end side alignment jig 6b. The contact surface 18 of the core jig 6b is configured to approach the sensor 4. Therefore, it is possible to improve the alignment property by the alignment jig 6 while facilitating the transfer of the sensor 4 to the vicinity of the inner surface 102 of the pipe 100 to be inspected.

Also, in some embodiments, the contact surface 18 is formed of a material that is more wear resistant than the rest of the elastic portion 12. This material is, for example, a non-magnetic material such as Inconel or SUS. Therefore, it is possible to prevent the contact surface 18 from being damaged by contact with the inner surface 102 of the pipe 100.
By coating the contact surface with hydrocarbons, carbon, or the like, DLC (diamond-like carbon) having better wear resistance than other parts of the elastic portion 12 is formed on the contact surface 18. May be.

In some embodiments, as shown in FIG. 1, the flexible tube 2 comprises a plurality of spherical bodies 30 that are spaced apart along the outer peripheral surface 2a of the flexible tube 2. When the diameter of the flexible tube 2 is L1 and the interval is L2, 3 ≦ L2 / L1 ≦ 6.

In the embodiment shown in FIG. 1, the flexible tube 2 includes seven spherical bodies 30 mounted at equal intervals along the outer peripheral surface 2a of the flexible tube 2. These spherical bodies 30 are formed of, for example, a resin material, and when the flexible tube 2 is inserted into the pipe 100, the frictional resistance generated by the spherical body 30 coming into contact with the inner surface 102 of the pipe 100 is reduced. Can be done. Further, in some embodiments, the spherical body 30 is configured to have an outer diameter substantially the same as the inner diameter of the pipe 100.

According to such a configuration, when the flexible tube 2 is inserted into the pipe 100 and the sensor 4 is conveyed to the vicinity of the inner surface 102 of the pipe 100 to be inspected, the flexible tube 2 is provided with a plurality of spherical bodies 30. It is possible to prevent the outer peripheral surface 2a from coming into contact with the inner surface 102 of the pipe 100.

Further, when the size of the diameter of the flexible tube 2 is L1 and the interval is L2, by setting 3 ≦ L2 / L1 ≦ 6, the transfer conditions of the pusher type transfer device (flexible tube provided with a plurality of spherical bodies 30). When inserting the flexible tube 2 into the inside of the pipe 100 and transporting the sensor 4 to the vicinity of the inner surface 102 of the pipe 100 to be inspected while satisfying the mechanical restriction for inserting the 2 into the inside of the pipe 100). , It is possible to prevent the flexible tube 2 from buckling inside the pipe 100.

Further, in some embodiments, as shown in FIG. 1, the flexible tube 2 includes a tip guide portion 44 provided at the tip portion 40 of the flexible tube 2. The tip guide portion 44 has a spherical shape.

Further, in some embodiments, the tip guide portion 44 may include a cone-shaped guide portion having an apex on the tip side of the flexible tube 2.

According to such a configuration, when the flexible tube 2 passes through a portion where the cross-sectional shape of the pipe 100 changes (for example, the bend portion of the pipe 100), the tip guide portion 44 comes into contact with the inner surface 102 of the bend portion. This induces the flexible tube 2. Therefore, the flexible tube 2 can be smoothly inserted into the pipe 100, and the sensor 4 can be conveyed to the vicinity of the inner surface 102 of the pipe 100 to be inspected.

Also, in some embodiments, the tip 40 of the flexible tube 2 is made of a material that is more flexible than the rest of the flexible tube 2. The tip portion 40 is formed of a rubber material such as fluororubber, silicon rubber, or nitrile rubber, and has a spring shape.

Here, the tip portion 40 of the flexible tube 2 is a portion of the flexible tube 2 from the tip guide portion 44 to the spherical body 30 arranged on the most tip side in the embodiment shown in FIG. The range of the tip portion 40 of the flexible tube 2 may change depending on the material used for forming the flexible tube 2.

According to such a configuration, when the flexible tube 2 passes through a portion where the cross-sectional shape of the pipe 100 changes (for example, the bend portion of the pipe 100), the tip portion 40 of the flexible tube 2 has a cross section of the bend portion. Depending on the shape, the flexible tube 2 is guided by bending before other parts of the flexible tube 2. Therefore, the flexible tube 2 can be smoothly inserted into the pipe 100, and the sensor 4 can be conveyed to the vicinity of the inner surface 102 of the pipe 100 to be inspected.

Although the eddy current flaw detector according to the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the object of the present invention. ..

1 Vortex current flaw detector 2 Flexible tube 2a Outer peripheral surface 4 Sensor 6 Alignment jig 6a Tip side alignment jig 6b Rear end side alignment jig 8 Array coil 10 Main body 12 Elastic part 13 Fitting hole 14 Screw 18 Contact Surface 19 Gap 22 Rotating body 24 First inclined surface 26 Second inclined surface 27 Spring 28 Plate-shaped member 30 Spherical body 40 Flexible tube tip 44 Tip guide 100 Piping 102 Inner surface 121 Leaf spring 123 Leaf spring tip 125 Support Part 127 Support shaft 181 Sliding contact surface 182 Outer peripheral surface

Claims (7)

A flexible tube that can be inserted inside the pipe,
A sensor attached to the flexible tube and generating an eddy current on the inner surface of the pipe to detect a change in the eddy current.
A main body having a fitting hole into which the flexible tube is fitted, and a plurality of elastic parts formed of an elastic material extending radially outward from the main body, wherein the inner surface of the pipe is formed. A plurality of elastic portions having a contact surface in contact with the sensor, and at least one alignment jig configured to enable alignment of the sensor .
The elastic portion is composed of a leaf spring extending diagonally outward from the main body portion.
The tip of the leaf spring includes two supports extending radially outward and a support shaft connecting one support and the other support.
A rotating body that can rotate in contact with the inner surface of the pipe is attached to the support shaft, and the outer peripheral surface of the rotating body constitutes the contact surface.
Eddy current flaw detector. The at least one alignment jig is a tip-side alignment jig mounted on the tip end side of the flexible tube with respect to the sensor, and after being mounted on the rear end side of the flexible tube with respect to the sensor. The eddy current flaw detector according to claim 1, further comprising an end-side alignment jig. The leaf spring of the tip side alignment jig extends toward the sensor in the longitudinal direction of the flexible tube.
The eddy current flaw detector according to claim 2, wherein the leaf spring of the rear end side alignment jig extends toward the sensor in the longitudinal direction of the flexible tube. The eddy current flaw detector according to any one of claims 1 to 3, wherein the contact surface is formed of a material having better wear resistance than other parts of the elastic portion. The flexible tube comprises a plurality of spherical bodies that are spaced apart along the outer peripheral surface of the flexible tube.
The eddy current flaw detector according to any one of claims 1 to 4, wherein 6 ≧ L2 / L1 ≧ 3 when the diameter of the flexible tube is L1 and the distance is L2. The flexible tube includes a tip guide portion provided at the tip portion of the flexible tube.
The eddy current flaw detector according to any one of claims 1 to 5, wherein the tip guide portion has a spherical shape. The eddy current flaw detector according to any one of claims 1 to 6, wherein the tip portion of the flexible tube is formed of a material having higher flexibility than other parts of the flexible tube.

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