JP6006990B2 - Eddy current testing probe - Google Patents

Description

  The present invention relates to an eddy current probe used for eddy current flaw detection for inspecting a subject nondestructively.

  The principle of eddy current flaw detection is to induce an eddy current in a test object by an alternating magnetic field generated by a coil for a conductive test object, and to detect the defect from a change in the impedance of the coil caused by the eddy current disturbance due to the defect. This is a method for evaluating the presence or absence.

  An eddy current flaw detection method in which an eddy current flaw detection probe is inserted into the inner surface of a pipe has been known in the past, and has been widely put into practical use especially for application to heat transfer tubes and the like. As the heat transfer tube, a U-shaped tube having a straight tube (straight tube portion) and a bent portion (curved tube portion) is widely used.

  In this non-destructive inspection of the heat transfer tube, a probe dedicated to a bent tube portion in which the diameter of the eddy current flaw detection probe is made smaller than when a straight tube portion is inspected when a bent tube portion is provided.

  The heat transfer tube has many bent tube portions, and when performing an inspection by inserting an eddy current flaw detection probe into the heat transfer tube, it is necessary that the passage is good.

  Patent Document 1 includes a detection coil unit and a plurality of electronic circuit units that process signals from the detection circuit unit. The detection coil unit and the plurality of electronic circuit units are serially connected to each other by a flexible tube. An eddy current flaw detection probe is disclosed which is connected to the

  By the structure described in the said patent document 1, the permeability in the curved pipe part inside a heat exchanger tube is improved.

JP-A-11-83810

  However, in the technique described in Patent Document 1 above, it is possible to improve the passability in the bent tube portion inside the heat transfer tube, but about shortening the distance between the eddy current flaw detection probe and the inner surface of the heat transfer tube. Not considered.

  In other words, the probe dedicated to the curved pipe part in the prior art has a small probe diameter, so the distance (lift-off) between the pipe inner surface and the eddy current flaw detection probe in the curved pipe part becomes long, and the detection sensitivity of defects and thinning decreases. There is a problem to do. This is because the detection sensitivity is lowered particularly in the portion where the radius of curvature of the bent tube portion is small.

  An object of the present invention is to realize an eddy current flaw detection probe that can improve flaw detection sensitivity while maintaining good passability even in a pipe having a curved pipe portion.

  In order to achieve the above object, the present invention is configured as follows.

  In an eddy current flaw detection probe, a plurality of coils are arranged, a flexible multi-coil sensor, an elastic body that supports the multi-coil sensor, and the multi-coil sensor is pressed against the inner surface of the pipe via the elastic body. And means for causing the multi-coil sensor to face the inner surface of the pipe.

  ADVANTAGE OF THE INVENTION According to this invention, even if it is piping which has a curved pipe part, the eddy current flaw detection probe which can improve a flaw detection detection sensitivity can be implement | achieved, maintaining favorable passability.

It is structure explanatory drawing of the eddy current flaw detection probe which is 1st Example of this invention. FIG. 2 is a view of a cross section taken along line A-A ′ of FIG. It is structure explanatory drawing of the eddy current flaw detection probe which is the 2nd Example of this invention. It is a figure which shows the shape at the time of arrange | positioning the flaw detection probe of a 1st and 2nd Example inside a heat exchanger tube. It is a figure which shows the shape at the time of arrange | positioning the flaw detection probe of a 1st and 2nd Example inside a heat exchanger tube. It is explanatory drawing of the example which connected the probe guide part to the eddy current test probe of this invention. It is explanatory drawing at the time of arrange | positioning the eddy current flaw detection probe of this invention in the curved pipe part in a heat exchanger tube. It is a figure explaining the example in the case of connecting several eddy current flaw detection probes of this invention mutually. It is structure explanatory drawing of the eddy current flaw detection probe which is the 3rd Example of this invention. FIG. 10 is a view of a cross section taken along line B-B ′ of FIG. It is structure explanatory drawing of the eddy current flaw detection probe which is the 4th Example of this invention. It is a figure which shows the shape at the time of arrange | positioning the flaw detection probe of a 3rd and 4th Example inside a heat exchanger tube. It is a figure which shows the shape at the time of arrange | positioning the flaw detection probe of a 3rd and 4th Example inside a heat exchanger tube. It is explanatory drawing of the example which connected the probe guide part to the eddy current test probe of this invention. It is explanatory drawing at the time of arrange | positioning the eddy current flaw detection probe of this invention in the curved pipe part in a heat exchanger tube. It is a figure explaining the example in the case of connecting several eddy current flaw detection probes of this invention mutually. It is a figure explaining the example at the time of attaching a some disk-shaped or spherical member to a guide part. It is explanatory drawing at the time of arrange | positioning the eddy current test probe of this invention in the heat exchanger tube inner surface. It is structure explanatory drawing of the eddy current flaw detection probe which is the 5th Example of this invention. It is structure explanatory drawing of the eddy current flaw detection probe which is the 5th Example of this invention. It is structure explanatory drawing of the eddy current flaw detection probe which is the 5th Example of this invention. It is explanatory drawing of the 6th Example of this invention. It is explanatory drawing of the 6th Example of this invention. It is explanatory drawing of the 6th Example of this invention. It is explanatory drawing of the 6th Example of this invention. It is structure explanatory drawing of the 7th Example of this invention. It is structure explanatory drawing of the 7th Example of this invention. It is structure explanatory drawing of the 7th Example of this invention. It is explanatory drawing of the modification of the probe guide mechanism in the 7th Example of this invention. It is explanatory drawing of the other modification of the probe guide mechanism in the 7th Example of this invention. It is explanatory drawing of the other modification of the probe guide mechanism in the 7th Example of this invention. It is explanatory drawing of the other modification of the probe guide mechanism in the 7th Example of this invention.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

(First embodiment)
1 and 2 are explanatory views of the structure of an eddy current flaw detection probe according to the first embodiment of the present invention. FIG. 1 is a view of an eddy current flaw detection probe as viewed from one direction, and the eddy current flaw detection probe advances in the heat transfer tube in the X direction among the illustrated XY directions. 2 is a view of a cross section taken along line AA ′ of FIG.

  A probe that is inserted into a pipe and performs flaw detection is generally called an interpolated probe.

  1 and 2, the eddy current flaw detection probe according to the first embodiment of the present invention includes a multi-coil sensor 100 in which a plurality of coils 130 are regularly arranged and flexibly bent (having flexibility), An elastic body 101 arranged on the opposite side of the multi-coil sensor 100 (the side opposite to the side facing the inner surface of the pipe to be inspected) and means for pressing the multi-coil sensor 100 (spring 103, spring support member 107) ) And means for causing the multi-coil sensor 100 to face the inner surface of the pipe (the sensor support member 104, the wheel support member 105, and the wheel 106).

  As shown in FIGS. 1 and 2, the multi-coil sensor 100 has a rectangular shape, and an elastic body 101 is disposed so as to cover a coil 130 disposed in the multi-coil sensor 100, and the elastic body 101 is disposed on the side opposite to the sensor. A leaf spring 102 is disposed. Means for pressing the multi-coil sensor 100 toward the surface to be measured includes a spring support member 107 and a spring 103.

  Means for causing the multi-coil sensor 100 to face the inner surface of the pipe includes a member 104 that connects to the sensor 100 and a member 105 that connects the wheel 104 and the member 104 disposed on both sides of the sensor 100 in the X direction. This means for facing is operated with the spring support member 107 as an axis. As shown in FIG. 2, the sensor support member 104 has a cylindrical space formed therein, and the spring support member 107 is supported in the space so as to be able to reciprocate. By receiving the elongation force of the spring 103 by the member 104, the sensor 100 can move in the Y-axis direction of FIG.

  A wheel 108 is disposed on the side opposite to the sensor of the member 107. The eddy current flaw detection probe according to the first embodiment of the present invention is inserted into the heat transfer tube so that the X axis coincides with the axial direction of the heat transfer tube. Inside the heat transfer tube, the wheels 106 and 108 and the sensor 100 come into contact with the inner surface of the heat transfer tube. The longitudinal direction of the multi-coil sensor 100 is substantially the same as the circumferential direction of the heat transfer tube.

  When the two wheels 106 are in contact with the inner surface of the pipe, the sensor 100 disposed between the two wheels 106 and the inner surface of the pipe can be directly opposed. Since the multi-coil sensor 100 and the heat transfer tube are scanned in contact with each other at the time of inspection, a frictional resistance reducing unit may be provided in order to improve durability.

  As described above, according to the first embodiment of the present invention, the leaf spring 102 includes the multi-coil sensor 100 including the plurality of wheels for moving the inner surface of the pipe and the plurality of sensors supported by the elastic body 101. While supporting, it was configured to press the multi-coil sensor 100 against the inner surface of the pipe by the pressing means (103, 104, 107), so even with a pipe having a curved pipe part, while maintaining good passability, It is possible to realize an eddy current flaw detection probe that can improve flaw detection sensitivity.

(Second embodiment)
Next, a second embodiment of the present invention will be described.

  FIG. 3 is an explanatory view of the structure of an eddy current flaw detection probe according to the second embodiment of the present invention. The structure according to the second embodiment is an example that can cope with a case where the axial direction of the heat transfer tube and the X direction that is the traveling direction of the probe are shifted from each other while the probe is scanned inside the heat transfer tube.

  The wheel support member 121 supports the two wheels 106. The wheel support member 121 is supported by a shaft 120 formed on a sensor unit support member 122 (corresponding to the sensor unit support member 104 in the example of FIG. 1) so as to be rotatable. That is, the wheel support member 121 has a structure that can rotate around the shaft 120 that extends in the Z direction orthogonal to the X direction and the Y direction in FIG. 3.

  In the second embodiment of the present invention, the same effect as in the first embodiment can be obtained. Furthermore, in Example 2, highly sensitive flaw detection detection can be executed even when the axial direction of the heat transfer tube and the X direction, which is the traveling direction of the probe, are shifted from each other.

  Since the other configuration of the second embodiment is the same as that of the first embodiment, detailed description thereof is omitted. In the first and second embodiments, the elastic body 101 needs to be a porous sponge material, the leaf spring 102, the members 104, 105, 107, 120, 121, 122, and the wheel 106 should be made of a material that does not react to the sensor. For example, an insulating material such as plastic or resin is desirable.

  FIGS. 4 and 5 show shapes when the flaw detection probes of the first and second embodiments described above are arranged inside the heat transfer tube. The curved tube portion of the heat transfer tube into which the flaw detection probe is inserted has a flat cross-sectional shape, and the multi-coil sensor 100 is pressed against the curved portion having a large curvature in FIG. 4 and the curved portion having a small curvature in FIG. It shows the state.

  As shown in FIGS. 4 and 5, the wheel 106 (not shown in FIGS. 4 and 5) and the wheel 108 come into contact with the inner surface of the heat transfer tube 110 by pressing the flaw detection probe against the inner surface of the heat transfer tube. The multi-coil sensor 100 can be pressed against the inner surface of the heat transfer tube 110. Further, not only directly below the pressing portion, but also the entire surface of the multi-coil sensor 100 can be pressed against the inner surface of the heat transfer tube 110 by the action of the leaf spring 102 and the elastic body 101.

  Here, ideally, as shown in FIGS. 4 and 5, it is desirable that the flaw detection probe is pressed against a portion having a large curvature radius and a portion having a small curvature radius. Therefore, as shown in FIG. 6, the probe guide 111 is connected to the member 104 or 122, and the probe guide 111 is scanned while being pulled, so that a sensor having a large curvature radius and a small curvature radius is detected. The posture can be adjusted to press 100.

  The probe guide part 111 can be configured to have a characteristic of bending only in one direction by adopting a structure in which a number of short members are connected by connecting members.

  Scanning the flaw detection probe while pulling the probe guide part 111, the tip of the guide part 111 gradually follows the shape of the curved pipe part at the part that reaches the curved pipe part from the straight pipe part, and the direction of the flaw detection probe rotates in the target direction. The flaw detection probe can be arranged at a target position. In this manner, the multi-coil sensor 100 can be pressed in the direction as shown in FIG. 7 for the flaw detection probe that has reached the curved pipe portion.

  7A shows a state where the sensor 100 is pressed against a curved pipe portion of the heat transfer tube 110 having a large curvature radius, and FIG. 7B shows a curved pipe portion of the heat transfer tube 110 having a small curvature radius. The state which pressed the sensor 100 is shown.

  In addition, as shown in FIG. 8, by connecting a plurality of flaw detection probes in series in a state where they are rotated every 90 degrees with respect to the axial direction of the heat transfer tube, the entire inner surface of the heat transfer tube is scanned by one probe scan. Can be inspected.

(Third embodiment)
Next, a third embodiment of the present invention will be described.

  9 and 10 are explanatory views of the structure of an eddy current flaw detection probe according to a third embodiment of the present invention. FIG. 9 is a view of the eddy current flaw detection probe as viewed from one direction, and the eddy current flaw detection probe advances in the heat transfer tube in the X direction among the illustrated XY directions. FIG. 10 is a view of a cross section taken along line B-B ′ of FIG.

  The eddy current flaw detection probe according to the third embodiment of the present invention has a structure including two multi-coil sensors 100. As in the first embodiment, the third embodiment includes a multi-coil sensor 100 that flexibly bends a plurality of coils regularly arranged, and an elastic body 101 that is disposed on the non-inspection surface side of the multi-coil sensor 100. , Means for pressing the multi-coil sensor 100 (spring 103, member 107), and means for causing the multi-coil sensor 100 to face the inner surface of the pipe (sensor support members 104, 105, wheels 106).

  As shown in FIGS. 9 and 10, the elastic body 101 is disposed so as to cover the coil 130 disposed in the multi-coil sensor 100, and the leaf spring 102 is disposed on the opposite side of the elastic body 101 to the sensor. Means for pressing the multi-coil sensor 100 toward the surface to be measured includes a member 107 and a spring 103.

  Means for causing the multi-coil sensor 100 to face the inner surface of the pipe includes a member 104 connected to the sensor 100 and a wheel 106 disposed on both sides in the X direction of the sensor 100 and a wheel support member 105 connecting the member 104. This means for facing each other operates with the member 107 as an axis. By receiving the extension force of the spring 103 by the central member 140 and the support member 104, the sensor 100 can move in the Y-axis direction of FIG.

  A configuration similar to the above-described configuration forms a pair of flaw detection probes with the central member 140 therebetween.

  The eddy current flaw detection probe according to the third embodiment of the present invention is inserted into the heat transfer tube so that the X axis coincides with the axial direction of the heat transfer tube. Inside the heat transfer tube, the four wheels 106 and the two multi-coil sensors 100 come into contact with the inner surface of the heat transfer tube.

  The two wheels 106 provided on both sides of each multi-coil sensor 100 come into contact with the inner surface of the tube, so that the multi-coil sensor 100 and the inner surface of the tube can be opposed to each other.

  At the time of inspection, since the multi-coil sensor 100 and the heat transfer tube are scanned in contact with each other, a frictional resistance reducing means may be provided to improve durability. This can be achieved by providing a plurality of protrusions on the test surface side of the multi-coil sensor 100. Note that the member 107 is preferably an insulating material such as plastic or resin, which is required to be made of a material that does not react with the sensor.

  In the third embodiment of the present invention, the same effect as that of the first embodiment can be obtained. Furthermore, in the third embodiment, since the two multi-coil sensors 100 are arranged, it is possible to detect a large area of the inspection surface in one scan.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described.

  FIG. 11 is an explanatory view of the structure of an eddy current flaw detection probe according to the fourth embodiment of the present invention. The structure in the fourth embodiment is an example that can cope with a case where the axial direction of the heat transfer tube and the X direction, which is the traveling direction of the probe, are shifted from each other while the probe is scanned inside the heat transfer tube.

  The wheel support member 121 supports the two wheels 106. The member 121 is supported by a shaft 120 formed on the sensor member 122 so as to be rotatable. That is, the member 121 has a structure that can rotate around the shaft 120 that extends in the Z direction orthogonal to the X direction and the Y direction in FIG. 3. Since the other configuration of the fourth embodiment is the same as that of the third embodiment, detailed description thereof is omitted.

  In the fourth embodiment of the present invention, the same effect as in the third embodiment can be obtained. Furthermore, in Example 4, highly sensitive flaw detection detection can be performed even when the axial direction of the heat transfer tube and the X direction, which is the traveling direction of the probe, are shifted from each other.

  FIGS. 12 and 13 show the shapes when the flaw detection probes of the third and fourth invention embodiments described above are arranged inside the heat transfer tube. The curved tube portion of the heat transfer tube into which the flaw detection probe is inserted has a flat cross-sectional shape, and the multi-coil sensor 100 is pressed against the curved portion having a large curvature in FIG. 12 and the curved portion having a small curvature in FIG. It shows a state.

  As shown in FIGS. 12 and 13, by pressing the members 107 and 122, the wheel 106 (not shown in FIGS. 12 and 13) contacts the inner surface of the heat transfer tube 110, and the two multi-coil sensors 100 are moved. The inner surface of the heat transfer tube 110 can be pressed. Further, not only directly below the pressing portion, but also the entire surface of the multi-coil sensor 100 can be pressed against the inner surface of the heat transfer tube 110 by the action of the leaf spring 102 and the elastic body 101.

  Here, ideally, as shown in FIGS. 12 and 13, it is desirable that the flaw detection probe is pressed against a portion having a large curvature radius and a portion having a small curvature radius. Therefore, as shown in FIG. 14, the probe guide 111 is connected to the member 140, and the probe 100 is scanned while pulling the probe guide 111, so that the sensor 100 is placed in a portion with a large curvature radius and a portion with a small curvature radius. The posture can be adjusted to press. This structure is the same as the example shown in FIG.

  For example, when the multi-coil sensor 100 is pressed against a portion having a large curvature radius in the cross section of the curved pipe portion 110, the bending direction (surface) of the guide portion is fixed to the probe so as to coincide with the XY plane. When the multi-coil sensor 100 is pressed to a portion having a small radius of curvature in the cross section of the curved tube 110, the bending direction (surface) of the guide portion is fixed to the probe so as to be orthogonal to the XY plane.

  The probe is scanned while pulling the guide part 111, and the tip of the guide part 111 gradually follows the shape of the curved pipe part at the part that reaches the curved pipe part from the straight pipe part, and the direction of the probe rotates in the target direction. The probe can be placed in position. By pressing the multi-coil sensor 100 in the target direction as shown in FIG. 15 with the probe that has reached the curved tube portion in this way, a wide area can be inspected by one scan.

  Further, as shown in FIG. 16, the entire inner surface of the heat transfer tube is inspected by a single probe scan by connecting a plurality of flaw detection sensors rotated by 90 degrees with respect to the axial direction of the heat transfer tube at the guide portion 111. can do.

  Regarding the guide part 111 shown in FIGS. 6 and 14, as shown in FIG. 17, one or a plurality of disc-shaped or spherical members 112 may be provided in the guide part 111. With this configuration, as shown in FIG. 18, the probe can be scanned near the axial direction of the heat transfer tube even in the bent tube portion of the heat transfer tube 110. For this reason, the scanning property of the probe can be improved.

(Fifth embodiment)
Next, a fifth embodiment of the present invention will be described.

  FIG. 19 is an explanatory view of the structure of an eddy current flaw detection probe according to the fifth embodiment of the present invention. The fifth embodiment is a modification of the fourth embodiment shown in FIG.

  In FIG. 19, a plurality of coils 130 are regularly arranged, and the multi-coil sensor 100 that bends flexibly, the elastic body 101 disposed on the side opposite to the inspection surface of the multi-coil sensor 100, and the opposite side of the elastic body 101 disposed on the sensor side. The leaf spring 102 is provided. The wheel support member 121 supports the multi-coil sensor 100, the elastic body 101, and the leaf spring 102 and supports the two wheels 106.

  However, in the fifth embodiment, the shaft 120 as in the fourth embodiment is not formed.

  A configuration similar to the above-described configuration forms a pair of flaw detection probes with the elastic member 150 interposed therebetween.

  When the eddy current flaw detection probe according to the fifth embodiment of the present invention is inserted into the pipe, the multi-coil sensors 100 arranged at both ends are pressed by the elastic member 150 and the leaf spring 102 and pressed by the pipe inner surface. The

  Here, since the multi-coil sensor 100 and the heat transfer tube to be inspected are contacted and scanned during inspection, means for improving durability and reducing frictional resistance are provided.

  Further, the leaf spring 102 attached to the elastic body 101 disposed on the side opposite to the inspection surface of the multi-coil sensor 100 may have a shape bent in advance as shown in FIG. FIG. 21 shows a case where such a sensor 100 is inserted into the tube 110 to be inspected. As shown in FIG. 21, the pipe 110 shows a flat state at the bent pipe portion.

  In the fifth embodiment, the same effect as that of the fourth embodiment can be obtained. Furthermore, according to the fifth embodiment, the configuration is simpler than that of the fourth embodiment, and the size and weight can be reduced.

  Further, in the example shown in FIG. 21, the area of the multi-coil sensor 100 that contacts the pipe 110 in the circumferential direction of the cross-section is enlarged so that the multi-coil sensors 100 arranged vertically can contact the entire circumference of the inner surface of the pipe. It is also possible to configure.

  In this case, the flaw detection can be reliably performed over the entire area of the inner surface of the tube without rotating the sensor 100 in a spiral shape, and the inspection accuracy can be improved and the inspection time can be shortened. is there.

(Sixth embodiment)
Next, a sixth embodiment of the present invention will be described.

  Since the multi-coil sensor according to the fifth embodiment of the present invention described above is pressed against the inner surface of the pipe to be inspected in the direction in which the two sensor portions face each other, the inner surface of the pipe is prevented in order to prevent interference between the sensors. The contact area may need to be 90 to 180 degrees in the circumferential direction.

  Therefore, in the sixth embodiment of the present invention, as shown in FIG. 22, two wheel support members 121 having a multi-coil sensor and provided with wheels before and after the axial direction of the pipe to be inspected are elastic bodies. Two probes 200 connected at 150 are connected to each other by being rotated by 90 degrees different from each other in the axial direction of the inspection target tube. Other configurations are the same as those of the fifth embodiment.

  With such a structure, two probes 200 can be inserted into the inspection target tube, and the inner surface of the tube can be contacted over 360 degrees using a plurality of multi-coil sensors 100.

  Also, a probe guide mechanism 151 for arranging the multi-coil sensor 100 of the probe 200 on the short axis, the long axis, or both the short axis and the long axis of the flat cross section in the flat cross section at the bent portion of the heat transfer tube is shown in FIG. 22. This probe guide mechanism 151 is a probe guide mechanism connected to the two probes 200, has a structure that bends on one plane, and its tip rotates in a direction around the axis of the inspection target tube. It has a structure.

  As shown in FIG. 23, the structure Q that bends in one plane has a connecting arm 220 that connects a plurality of spherical parts 212 to each other, and a shaft hole 221 is formed at the end of the connecting arm 220. Yes. Further, a groove 222 for connecting the connecting arm 220 and a shaft hole 223 for inserting the connecting rod 224 are formed.

  The connecting arm 220 of one spherical component 212 is inserted into the groove 222 of another adjacent spherical component 212 and the connecting rod 24 is inserted into the connecting shaft holes 221 and 223. With this structure, a bent structure having only one axis is formed, and a structure Q that is bent in one plane direction is obtained.

  Similarly to the mechanism Q, the rotating mechanism R connected subsequent to the structure Q has a connecting arm 230 for connecting a plurality of spherical parts 213 to each other as shown in FIG. A shaft hole 231 is formed at the tip of the arm 230. Further, a groove 232 for connecting the connecting arm 230 and a shaft hole 233 for inserting the connecting rod 234 are formed.

  The spherical members 231 are designed such that the width L2 of the groove 232 is larger than the thickness L1 of the connecting arm 230 so that the spherical members 231 can rotate with respect to the extension line of the connecting arm 230 as an axis.

  In addition, the shaft holes 231 and 233 are designed so that the diameter thereof is larger than the thickness dimension of the connecting shaft 234. How much the diameter of the shaft holes 231 and 233 is larger than the thickness dimension of the connecting shaft 234 depends on the structure R of the probe guide mechanism 151 and the allowable rotation angle is 90. Design to be within degrees. That is, it is designed so that the total allowable rotation angle of the plurality of spherical members 213 is within 90 degrees.

  A probe guide mechanism 151 for disposing the probe 200 having the multi-coil sensor 100 on the short axis, the long axis, or both of the flat cross section with respect to the flat cross section at the bent portion of the heat transfer tube to be inspected. By using the probe 200, the probe 200 can be bent smoothly in a single plane direction and can also be rotated in the circumferential direction of the inspection target tube. Can be guided. Therefore, as shown in FIG. 25, the probe 200 can be pressed against the short axis, the long axis, or both of the tube against the flat section of the bent portion of the tube to be inspected.

  The elastic body 101 can use a porous sponge material, and the leaf spring 102, the wheel support member 121, the elastic member 150, and the wheel 106 need to be made of a material that does not react to the sensor 100. Insulating material is desirable.

  According to the sixth embodiment of the present invention, the flaw detection can be reliably performed over the entire inner surface of the tube without rotating the sensor 100 in a spiral shape, and the accuracy of the inspection can be improved. Inspection time can be shortened.

(Seventh embodiment)
Next, a seventh embodiment of the present invention will be described.

  FIG. 26 is a schematic configuration diagram of the seventh embodiment of the present invention.

  In FIG. 26, the probe 200 presses the multi-coil sensor 100, which flexibly bends the multi-coil sensor 100 in which a plurality of coils 130 are regularly arranged, the elastic body 101 arranged on the opposite side of the multi-coil sensor 100, and the multi-coil sensor 100. The elastic member 150 is provided.

  As shown in FIG. 26, the elastic body 101 and the leaf spring 102 are arranged on the side opposite to the sensor of the elastic body 101. A member connected to the leaf spring 102 is a carriage 121 in which wheels 106 are arranged on both sides in the X direction shown in FIG. The two carts 121 are arranged so as to be symmetrical with each other with the elastic member 150 therebetween, and are connected by the elastic member 150. The cart 121 shown in the lower part of FIG. Is not arranged.

  The elastic member 150 is formed of a leaf spring or a spring. The probe 200 in the seventh embodiment of the present invention is inserted so that the X axis shown in FIG. 26 and the axial direction of the heat transfer tube to be inspected coincide with each other, and the wheel 106 and the sensor 100 are disposed inside the heat transfer tube. It will contact the inner surface.

  The two wheels 106 are brought into contact with the inner surface of the heat transfer tube, so that the sensor 100 disposed between the two wheels 106 and the inner surface of the tube can face each other. Since the multi-coil sensor 100 and the heat transfer tube are scanned in contact with each other at the time of inspection, measures for reducing frictional resistance are taken in order to improve durability.

  FIG. 27 shows a case where the probe 200 is inserted into the tube to be inspected. The pipe | tube 110 shown in FIG. 27 has shown the state flattened by the bending pipe part. The multi-coil sensor 100 in the seventh embodiment is pressed in the direction facing the inner surface of the tube, and the contact area with the inner surface of the tube is within a range of 180 to 360 degrees in the circumferential direction.

  If the contact area with the pipe inner surface is 360 degrees, the contact area with the pipe inner surface can be the entire area in the circumferential direction of the pipe.

  When the contact area with the inner surface of the tube is less than 180 to 360 degrees in the circumferential direction, it is necessary to rotate the probe to detect the entire region of the inner surface of the tube with only one probe.

  Therefore, as shown in FIG. 28, the probe 200 having two multi-coil sensors 100 rotated 180 degrees from each other is connected to each other.

  Thus, by inserting the two connected probes 200 into the tube, the inner surface of the tube can be contacted over 360 degrees using a plurality of multi-coil sensors 100. Also, the means for arranging the multi-coil sensor 100 shown in FIG. 28 on the short axis, the long axis, or both with respect to the flat cross section at the bent portion of the heat transfer tube is the same as in Example 6, and FIG. The configuration is the same as the arrangement component 151 described.

  FIG. 29 is a view showing a modified example of the probe guide mechanism 151 described above. In FIG. 29, since spherical parts 212 and 213 are in contact with the inner surface of the pipe to be inspected, it is desirable to take measures against wear. In view of this, the part 205 that contacts the inner surface of the pipe of the spherical parts 212 and 213 is made of engineering plastic and a resin-based material having excellent wear resistance. For the other parts of the spherical parts 212 and 213, for example, a material that is not a magnetic material such as aluminum or stainless steel can be used.

  30 to 32 are diagrams showing other modified examples of the arrangement component 151 described above.

  A wiring 235 for transmitting an output signal from the multi-coil sensor 100 is connected to the probe 200. In the example shown in FIGS. 30 to 32, a wiring hole 236 into which the wiring 235 is inserted into the spherical component 212 is formed.

  Since the wiring 235 has a length equal to or greater than the length of the tube to be inspected, it can be considered that the wire 235 moves in an unexpected direction inside the tube and hinders the rapid movement of the probe 200. Therefore, as shown in FIGS. 30 and 31, if the wiring 235 is inserted into the wiring hole 236, it is possible to suppress movement in an unexpected direction inside the pipe.

  In many cases, the wiring 235 is formed of a flexible printed circuit board. When such a printed circuit board moves in an unexpected direction in the tube, there is a possibility that it is difficult to move the probe 200 quickly. Therefore, when a printed circuit board is used for the wiring 235, if the wiring is inserted into the wiring hole 236, the wiring can be prevented from moving in an unexpected direction inside the pipe.

  In the illustrated example, the diameter of the spherical component 212 is larger than the diameter of the spherical component 213, but the diameter of the spherical component 212 and the diameter of the spherical component 213 can be the same.

  According to the seventh embodiment of the present invention, the flaw detection can be reliably performed over the entire area of the inner surface of the tube without rotating the sensor 100 in a spiral shape, and the accuracy of the inspection can be improved. Inspection time can be shortened.

  As described above, according to the present invention, the occurrence of lift-off at the bent tube portion of the heat transfer tube is suppressed by pressing the flexiblely bent multi-coil sensor in which a plurality of coils are regularly arranged on the inner surface of the tube. Therefore, it is possible to inspect the bent pipe portion without reducing the detection sensitivity for defects and thinning.

  Further, since the inner surface 360 degrees of the tube can be inspected by a combination of a plurality of sensors or a combination of a plurality of probes 200, the probe may be moved in one direction along the axial direction of the tube. In this way, prolongation of the inspection time can be prevented. When multiple sensors or probes are not used, it is necessary to move the probe in the axial direction while rotating the probe in the circumferential direction of the tube to scan the inside of the tube in a spiral manner. This is because time is required.

  DESCRIPTION OF SYMBOLS 100 ... Multi coil sensor, 101 ... Elastic body, 102 ... Leaf spring, 103 ... Spring, 104, 122 ... Sensor part support member, 105, 121 ... Wheel support member, 106 , 108 ... wheels, 107 ... spring support members, 110 ... heat transfer tubes, 111 ... probe guides, 120 ... shafts, 130 ... coils, 140 ... central members, 150 ... Elastic member, 151 ... Probe guide mechanism, 200 ... Probe, 212, 213 ... Spherical parts, 220, 222 ... Groove, 221, 223, 231, 233 ... Hole, 230 ... Connecting arms, 224, 234 ... Connecting rods, 235 ... Wiring, 236 ... Wiring holes

Claims (8)

In the eddy current flaw detection probe that is inserted into the pipe and flaws the pipe inner surface,
A plurality of coils for detecting piping defects are arranged, a flexible multi-coil sensor, an elastic body that supports the multi-coil sensor, and the multi-coil sensor on the inner surface of the pipe via the elastic body. A plurality of eddy current flaw detection probes having means for pressing and means for causing the multi-coil sensor to face the inner surface of the pipe;
Each of the plurality of spherical parts has a plurality of spherical parts formed with a plate-like connecting arm having a shaft hole formed at the tip, a rectangular groove, and a hole leading to the rectangular groove. The plate-like connecting arm is inserted into the rectangular groove of the adjacent spherical component, and is connected to the shaft hole formed in the inserted plate-like connecting arm and the hole leading to the groove. A probe guide mechanism in which rods are inserted and connected to each other so as to bend in a plane direction;
Of the plurality of coil probe, the eddy current flaw detection probe that are adjacent to each other, eddy currents, characterized in that connected to the probe guide mechanism in a position rotated by 90 degrees from each other with respect to the said probe guide mechanism Flaw detection probe. The eddy current flaw detection probe according to claim 1,
The multi-coil sensor has a rectangular shape, and the plurality of coils are regularly arranged in the longitudinal direction of the multi-coil sensor. The eddy current flaw detection probe according to claim 2,
The eddy current flaw detection probe according to claim 1, wherein the elastic body is in contact with the entire area of the multi-coil sensor. The eddy current flaw detection probe according to claim 3,
The means for causing the multi-coil sensor to face the inner surface of the pipe has a pair of wheels that are arranged with the multi-coil sensor in between and in contact with the inner surface of the pipe for running the eddy current flaw detection probe in the pipe. An eddy current flaw detection probe. The eddy current flaw detection probe according to claim 4,
An eddy current flaw detection probe according to claim 1, wherein a longitudinal direction of the multi-coil sensor is a direction substantially orthogonal to a traveling direction of the pair of wheels. In the eddy current flaw detection probe according to claim 5,
The eddy current flaw probe according to claim 1, wherein the means for directly facing each other includes a wheel support member for supporting the pair of wheels, and a shaft member for supporting the wheel support member by the means for pressing the wheel support member. The eddy current flaw detection probe according to claim 1,
The two pressing means have two each of the multi-coil sensor, the elastic body, the pressing means, and the means for facing each other so that the two multi-coil sensors are located at both ends. Eddy current flaw detection probes characterized by being connected to each other. The eddy current flaw detection probe according to claim 1,
The multi-coil sensor, the elastic body, and the two means for facing each other are provided, and the two multi-coil sensors are arranged via the pressing means so that the two multi-coil sensors are located at both ends. An eddy current flaw detection probe characterized in that the means for causing them are connected to each other.

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