JP5487468B2 - Pipe inspection device - Google Patents

Description

  The present invention relates to a pipe inspection apparatus for flaw-inspecting a welded part of a pipe using an ultrasonic probe, and in particular, branches to an outer peripheral part of the mother pipe so that the mother pipe and the branch pipe are different in diameter and substantially orthogonal to each other. The present invention relates to a pipe inspection apparatus for inspecting a welded portion in which an end portion of a pipe is butt welded.

  For example, in the base part of the primary recirculation system piping of the boiling water nuclear power plant, as shown in FIG. 17, the diameter of the branch pipe 2 is smaller than that of the mother pipe 1, and the mother pipe 1 and the branch pipe 2 are almost equal. There is a welded portion 3 (indicated by a weld line 3a in FIG. 17) in which the end of the branch pipe 2 is butt welded to the outer peripheral portion of the mother pipe 1 so as to be orthogonal to each other. 2. Description of the Related Art Conventionally, a pipe inspection support device that identifies a weld line 3a that is a center line of a welded part 3 before flaw detection inspection of such a welded part 3 has been disclosed (for example, see Patent Document 1).

  This pipe inspection support device is attached to the outer peripheral side of the branch pipe and is attached to the annular guide rail extending in the circumferential direction of the branch pipe, and capable of rotating around the guide rail, that is, movable in the circumferential direction of the branch pipe. Probe turning device, a turning drive device for moving the probe turning device in the circumferential direction of the branch pipe relative to the guide rail, and an axial direction (for example, vertical direction) of the branch pipe fixed to the probe turning device A first support arm extending to the probe, a probe moving device slidably attached to the first support arm, that is, movable in the axial direction of the branch pipe, and a probe to the first support arm A vertical drive device for moving the moving device in the axial direction of the branch pipe, and a second support arm attached to be slidable with respect to the probe moving device, that is, movable in the radial direction (for example, horizontal direction) of the branch pipe This second branch The second probe arm and the ultrasonic probe are moved in the radial direction of the branch pipe with respect to the ultrasonic probe (for example, a vertical probe) provided on the arm via the spherical bearing and the probe moving device. And a horizontal driving device. The ultrasonic probe can be moved in the circumferential direction, the axial direction, and the radial direction of the branch tube by driving the turning drive device, the vertical drive device, and the horizontal drive device.

  Further, the pipe inspection support device includes a control device for driving and controlling the turning drive device, the vertical drive device, and the horizontal drive device based on the position of the ultrasonic probe instructed by the input device, and the ultrasonic probe. An ultrasonic signal processing device (welding line specifying device) that outputs an excitation command for transmitting ultrasonic waves and processes a reflected signal of the ultrasonic waves received by the ultrasonic probe is provided. For example, when an operator instructs the position of the ultrasonic probe and the start of ultrasonic transmission with the input device, the ultrasonic probe moves to the position indicated by the input device, and then in the radial direction of the branch pipe. While moving (scanning), an ultrasonic wave is transmitted toward the welded portion 3 and the like, and a reflection signal thereof is received. Then, the ultrasonic signal processing device identifies the center position of the welded portion 3 (specifically, the center position in the radial direction of the branch pipe 2) based on the ultrasonic reflection signal received by the ultrasonic probe, The elliptical shape and position of the weld line 3a are specified from the center positions of at least two places (for example, azimuth angle θ = 0 °, 90 °), and the position information of the specified weld line 3a is displayed on the display device. Yes.

JP 2008-101978 A (FIG. 1 etc.)

  In Patent Document 1, after the welding line 3a is specified by the pipe inspection support device, the worker scans the welded portion 3 by scanning the ultrasonic probe with his / her hand. Therefore, there is a desire to automatically scan the ultrasonic probe using the same configuration as the pipe inspection support device in the flaw detection inspection of the welded portion 3. However, in this case, there are the following problems.

  As shown in FIG. 7B and the like of Patent Document 1, the guide rail has a substantially circular track. Therefore, as shown in FIG. 18, when viewed from the axial direction of the branch pipe 2 (in other words, when projected onto the radial section of the branch pipe 2), an ultrasonic probe (for example, an oblique probe). ) 4 transmits ultrasonic waves in a direction toward the axis O of the branch pipe 2, and the ultrasonic transmission direction line A1 has an azimuth (specifically, the axis O of the branch pipe 2 is centered on FIG. 18). It is an angle that advances counterclockwise and overlaps with the direction line B of the axis 1 of the main tube 1 at 0 ° and 180 °. On the other hand, when viewed from the axial direction of the branch pipe 2, the weld line 3a has an elliptical shape having a minor axis at an azimuth angle θ = 0 ° and 180 ° and a major axis at an azimuth angle θ = 90 ° and 270 °. Accordingly, the ultrasonic transmission direction line A1 at an azimuth angle θ other than 0 °, 90 °, 180 °, and 270 ° is a perpendicular line to the elliptical weld line 3a (specifically, in the elliptical weld line 3a). An angle difference Δθ occurs between a tangent line having a predetermined position as a contact point and a vertical line (C) having the predetermined position as an intersection, and the angle difference Δθ also varies according to the azimuth angle θ.

  Here, in the standard JEAC 4207-2008 established by the Nuclear Standards Committee of the Japan Electric Association, it is proposed that the ultrasonic wave transmission direction of the ultrasonic probe is a direction perpendicular to the weld line. The reason is that when a crack or the like occurs in the welded portion 3, the crack is likely to occur in a shape along the weld line 3a, and the ultrasonic transmission direction of the ultrasonic probe 4 is perpendicular to the weld line 3a. This is because the flaw detection accuracy is improved. Therefore, according to the azimuth angle θ, the ultrasonic transmission direction line of the ultrasonic probe 4 is brought close to the perpendicular direction line C with respect to the elliptical welding line 3 to improve the flaw detection accuracy.

  A first object of the present invention is to provide a pipe inspection apparatus capable of improving flaw detection accuracy.

  Further, as shown in FIG. 19A, in the cross section at the azimuth angle θ = 0 ° (and θ = 180 °), the surface of the mother pipe 1 extends to a straight line perpendicular to the axial direction of the branch pipe 2. Exists. On the other hand, as shown in FIG. 19B, the surface of the mother pipe 1 extends in a true arc shape in a cross section with an azimuth angle θ = 90 ° (and θ = 270 °). Although not shown, in the cross section of the range of 0 ° <θ <90 °, the range of 90 ° <θ <180 °, the range of 180 ° <θ <270 °, and the range of 270 ° <θ <360 °, The surface of the mother pipe 1 extends in an elliptical arc shape, and the oblateness of the elliptical arc varies according to the azimuth angle θ. In this way, the surface shape of the mother tube 1, that is, the scanning surface shape changes according to the azimuth angle θ.

  However, in Patent Document 1, the angle between the first support arm and the second support arm is fixed at about 90 °, and the scanning angle when the ultrasonic probe is scanned in the radial direction of the branch tube Is fixed. Therefore, it is difficult to position the ultrasonic probe on the surface of the mother tube 1 according to the azimuth angle θ, which is a problem in terms of scanning performance.

  A second object of the present invention is to provide a pipe inspection apparatus capable of improving the scanning performance.

(1) To achieve the first object, according to the present invention, the end of the branch pipe is butt welded to the outer peripheral portion of the mother pipe so that the mother pipe and the branch pipe are different in diameter and substantially orthogonal to each other. a weld, said the weld line when viewed from the axial direction of the branch pipe is inspected welds an elliptical shape, a circumferential direction of the branch pipe attached to the outer periphery of the branch pipe extending to the annular guide rail having a raceway which is a similar figure with respect to the weld line of the elliptical shape, interposed between said guide rail and the first frame, and travels the outer peripheral surface of the guide rail And a pair of guide rollers that are disposed on one side and the opposite side of the guide rail in the circumferential direction with respect to the running wheel and that run on the inner peripheral surface of the guide rail, The first frame with respect to the branch pipe A circumferential movement mechanism that moves in the circumferential direction, and an axial movement mechanism that is interposed between the first frame and the second frame and moves the second frame in the axial direction of the branch pipe with respect to the first frame. And a radial movement mechanism that is interposed between the second frame and the ultrasonic probe and moves the ultrasonic probe in a substantially radial direction of the branch pipe with respect to the second frame. In the pipe inspection device, when viewed from the axial direction of the branch pipe, the ultrasonic transmission direction line of the ultrasonic probe is relative to a tangent line having the ultrasonic incident position in the elliptical weld line as a contact point the so substantially overlap with the vertical line is referred to as an ultrasonic incident position of intersection, have a posture angle adjusting means for automatically adjusting the attitude angles with respect to the guide rails of the first frame in accordance with the movement position of the first frame, The running wheel is When viewed from the axial direction of the branch pipe, the reference line connecting the contact point of the traveling wheel and the rotation center point of the traveling wheel on the outer peripheral surface of the guide rail is the ultrasonic transmission direction of the ultrasonic probe. It is attached to the first frame so as to overlap the line, and the posture angle adjusting means is capable of moving each position of the pair of guide rollers with respect to the first frame in a substantially radial direction of the branch pipe, A pair of roller moving mechanisms configured such that their moving direction and moving range are line-symmetric with respect to the reference line, and the leading end side is connected to each of the rotation shafts of the pair of guide rollers, and the leading end side is the first frame. And a pair of tension springs that pulls the pair of guide rollers outwardly in the radial direction of the branch pipe, and the pair of tension springs has a rotation center position on the starting side of the pair of tension springs. Standard It is arranged to be line-symmetrical with respect to.

  In the present invention as described above, the posture angle of the first frame relative to the guide rail is automatically adjusted by the posture angle adjusting means according to the moving position (azimuth angle) of the first frame. As a result, when viewed from the axial direction of the branch pipe, the ultrasonic transmission direction line of the ultrasonic probe is perpendicular to the elliptical welding line (specifically, the ultrasonic wave incident on the elliptical welding line) A tangent line whose position is a contact point is almost overlapped with a vertical line whose intersection is an ultrasonic wave incident position. Therefore, the flaw detection accuracy can be improved.

( 2 ) In the above ( 1 ), preferably, the pair of roller moving mechanisms rotate the respective positions of the rotation shafts of the pair of guide rollers with respect to the first frame in a substantially radial direction of the branch pipe. It has an arm.

( 3 ) In the above ( 1 ), preferably, the pair of roller moving mechanisms are configured to slide the respective positions of the rotation shafts of the pair of guide rollers with respect to the first frame in a substantially radial direction of the branch pipe. It has a slider.

( 4 ) In the above (1) to ( 3 ), in order to achieve the second object, it is preferable to rotate the radial movement mechanism relative to the second frame in the axial direction of the branch pipe. Provide mechanism.

  In the present invention, when the ultrasonic probe is moved (scanned) in the substantially radial direction of the branch tube by rotating the radial direction moving mechanism with respect to the second frame by the rotating mechanism in the axial direction of the branch tube. The scanning angle can be adjusted. Therefore, the ultrasonic probe can be positioned on the surface of the mother tube according to the azimuth angle, and the scanning performance can be improved.

( 5 ) In the above ( 4 ), preferably, as a control table, for each movement position of the first frame by the circumferential movement mechanism, the rotation angle of the radial movement mechanism by the rotation mechanism, the axial movement Based on the control table stored in the storage means, the storage means for storing the axial movement position of the second frame by the mechanism and the scanning range of the ultrasonic probe by the radial movement mechanism, the circumferential movement A probe movement control means for controlling the mechanism, the rotation mechanism, the axial movement mechanism, and the radial movement mechanism.

( 6 ) In the above ( 5 ), preferably, a circumferential movement position calculation means for calculating a movement position of the first frame by the circumferential movement mechanism based on a movement amount pitch of the circumferential movement mechanism; Attitude angle calculating means for calculating an attitude angle of the first frame automatically adjusted by the ultrasonic wave transmission direction adjusting means for each moving position of the first frame calculated by the direction moving position calculating means, and the circumferential direction For each movement position of the first frame calculated by the movement position calculation means, the attitude angle of the first frame calculated by the attitude angle calculation means and the mother pipe, the branch pipe, and the welding stored in advance are stored. The cross-sectional shape of the pipe is calculated based on the structural data of the section. Based on the cross-sectional shape of the pipe, the rotation angle of the radial movement mechanism by the rotation mechanism and the second frame by the axial movement mechanism are calculated. A rotation angle / axial movement position / scanning range calculation means for calculating the axial movement position of the frame and the scanning range of the ultrasonic probe by the radial movement mechanism; and the storage means, As a control table, for each movement position of the first frame calculated by the circumferential movement position calculation means, the rotation of the radial movement mechanism calculated by the rotation angle / axial movement position / scanning range calculation means is calculated. The moving angle, the axial movement position of the second frame, and the scanning range of the ultrasonic probe are stored.

( 7 ) In the above ( 5 ) or ( 6 ), preferably, a slit is formed at a predetermined circumferential position of the guide rail, and the origin of the movement position of the first frame by the circumferential movement mechanism An origin position detector for detecting the position of the slit of the guide rail is provided in the first frame.

  According to the present invention, the flaw detection accuracy can be improved.

It is a side view showing the whole structure of one Embodiment of the piping inspection apparatus of this invention with the welding part which is a test object. It is a partial expanded side view showing the detailed structure of the guide rail and circumferential direction moving mechanism in one Embodiment of the piping inspection apparatus of this invention. FIG. 3 is a cross-sectional view taken along section III-III in FIG. 1 and shows a detailed structure such as an axial movement mechanism. FIG. 4 is a cross-sectional view taken along section IV-IV in FIG. 3 and shows a detailed structure of the radial movement mechanism and the rotation mechanism. FIG. 5 is a cross-sectional view taken along a cross-section VV in FIG. 4 and shows a detailed structure of the radial movement mechanism. FIG. 6 is a cross-sectional view taken along section VI-VI in FIG. 2, showing a detailed structure of the guide rail and the circumferential movement mechanism, and showing a case where the first frame is located at an azimuth angle θ = 0 °. FIG. 7 is a cross-sectional view taken along section VII-VII in FIG. 6 and represents a slit of the guide rail and a proximity sensor. It is a figure for demonstrating the effect | action of the circumferential direction moving mechanism in one Embodiment of the piping test | inspection apparatus of this invention, and shows the case where a 1st frame is located in azimuth | direction angle | corner (theta) = 50 degrees. It is a block diagram showing the functional structure of the control system in one Embodiment of the piping inspection apparatus of this invention. It is a flowchart showing the processing content of the control table preparation of the controller in one Embodiment of the piping inspection apparatus of this invention. Scanning cross section of the pipe in an embodiment of the pipe inspection apparatus of the present invention is a diagram illustrating with radially moving mechanism, showing a case where the first frame is positioned on the azimuth angle θ _{i =} 90 °. It is a figure showing the operation state of one embodiment of the piping inspection device of the present invention with the scanning direction section of piping, and when the 1st frame is located in azimuth angle θ ₀ = 0 ° and azimuth angle θ _i = 90 ° Indicates when to do. It is a figure showing as an example the control table memorize | stored with the controller in one Embodiment of the piping inspection apparatus of this invention. It is a flowchart showing the processing content of the flaw detection control of the controller in one Embodiment of the piping inspection apparatus of this invention. It is a side view showing the detailed structure of the guide rail and circumferential direction moving mechanism in other embodiment of the piping inspection apparatus of this invention. FIG. 16 is a cross-sectional view taken along a cross section XVI-XVI in FIG. 15, showing a detailed structure of the guide rail and the circumferential movement mechanism, and showing a case where the first frame is located at an azimuth angle θ = 0 °. It is a side view showing the welding part which is a test object of the piping inspection apparatus of this invention. It is the top view which looked at the welding part which is a test object of the piping inspection apparatus of this invention from the axial direction of the branch pipe. It is sectional drawing of the welding part which is a test object of the piping inspection apparatus of this invention, and each represents the cross section of azimuth angle = 0 degrees, and the cross section of azimuth angle (theta) = 90 degrees.

  Hereinafter, an embodiment of a pipe inspection apparatus of the present invention will be described with reference to the drawings.

  FIG. 1 is a side view illustrating the overall configuration of an embodiment of the pipe inspection apparatus according to the present invention together with a welded portion 3 to be inspected. FIG. 2 is a partially enlarged side view showing a detailed structure of the guide rail and the circumferential movement mechanism. FIG. 3 is a cross-sectional view taken along section III-III in FIG. 1 and shows a detailed structure such as an axial movement mechanism. FIG. 4 is a cross-sectional view taken along section IV-IV in FIG. 3 and shows a detailed structure of the radial movement mechanism and the rotation mechanism. FIG. 5 is a cross-sectional view taken along a cross-section VV in FIG. 4 and shows a detailed structure of the radial movement mechanism (for convenience, the rotation mechanism and the like are not shown).

  The pipe inspection apparatus is used for flaw detection inspection of the above-described welded portion 3 using the ultrasonic probe 4. As shown in FIG. 1 and the like, the pipe inspection apparatus includes an annular guide rail 5 that is attached to the outer peripheral side of the branch pipe 2 and extends in the circumferential direction of the branch pipe 2, and the guide rail 5 and the first frame 6. Between the first frame 6 and the second frame 8 and the first frame 6 with respect to the guide rail 5 and the first frame 6 in the circumferential direction of the branch pipe 2. An axial movement mechanism 9 for moving the second frame 8 relative to the frame 6 in the axial direction of the branch pipe 2 (vertical direction in FIG. 1), and the second frame 8 and the ultrasonic probe 4 are interposed, A radial direction moving mechanism 10 that moves the ultrasonic probe 4 in a substantially radial direction (left and right direction in FIG. 1) of the branch tube 2 with respect to the second frame 8 and a radial direction moving mechanism 10 that branches with respect to the second frame 8 are branched. And a rotation mechanism 11 for rotating the tube 2 in the axial direction. The ultrasonic probe 4 can be moved in the circumferential direction, the axial direction, and the substantially radial direction of the branch tube 2 by driving the circumferential direction moving mechanism 7, the axial direction moving mechanism 9, and the radial direction moving mechanism 10. . Further, the scanning angle when moving (scanning) the ultrasonic probe 4 in the substantially radial direction of the branch tube 2 is made variable by driving the rotation mechanism 11.

  As shown in FIGS. 1 to 3, the first frame 6 includes a first base plate 12 disposed on one end surface side (upper side in the drawing) of the guide rail 5 and a first auxiliary fixed to the first base plate 12. The plate 13 includes a second auxiliary plate 14 fixed to the first auxiliary plate 13, and a second base plate 15 disposed on the other end surface side (lower side in the drawing) of the guide rail 5. As shown in FIG. 3, the second base plate 15 and the first auxiliary plate 13 rotatably support the ball screw 16 of the axial movement mechanism 9 via a bearing (not shown). With such a structure, the second base plate 15 is configured integrally with the first auxiliary plate 13 and the like.

  As shown in FIG. 3, the axial movement mechanism 9 is fixed to the ball screw 16 extending in the axial direction (vertical direction in the drawing) of the branch pipe 2 and the second auxiliary plate 14, and the output shaft connects the joint 17. And an axial drive motor 18 connected to the ball screw 16. The axial direction drive motor 18 is provided with an encoder 19 for detecting the amount of rotation (rotation angle).

  As shown in FIG. 3 and the like, the second frame 8 has a nut 20a into which the ball screw 16 is screwed, and a moving plate 20 that moves in the extending direction of the ball screw 16 as the ball screw 16 rotates, A portal plate 21, a pair of slide shafts 22 </ b> A and 22 </ b> B coupled between the movable plate 20 and the portal plate 21, and a box 24 fixed to the portal plate 21 using two coupling screws 23, It consists of The slide shafts 22A and 22B are inserted into sleeves 25A and 25B provided on the second base plate 15, so that the moving direction of the second frame 8 is guided. When the ball screw 16 is rotated by driving the axial direction drive motor 18, the second frame 8 is moved in the extending direction of the ball screw 16 (that is, the axial direction of the branch pipe 2).

  As shown in FIG. 4 and the like, the radial direction moving mechanism 10 includes a frame frame 26 extending in a substantially radial direction (left and right direction in FIG. 4) of the branch pipe 2 and a bearing (not shown) on the frame frame 26. A ball screw 27 that is rotatably supported through the branch pipe 2 and extends in the substantially radial direction of the branch pipe 2, and a pair of slide shafts 28A and 28B that are fixed to the frame frame 26 and extend in the substantially radial direction of the branch pipe 2. A moving base 29 having a screw hole into which the ball screw 27 is screwed and an insertion hole into which the slide shafts 28A and 28B are inserted, and moving in the extending direction of the ball screw 27 and the like as the ball screw 27 rotates, and a frame frame 26, and the output shaft has a radial movement motor 31 connected to the ball screw 27 via a pair of bevel gears 30A and 30B (see FIG. 5). When the ball screw 27 is rotated by driving the radial direction drive motor 31, the moving base 29 is moved in the extending direction of the ball screw 27 and the like (that is, the substantially radial direction of the branch pipe 2). The radial drive motor 31 is provided with an encoder 32 for detecting the amount of rotation (rotation angle).

  As shown in FIG. 3 and FIG. 5 and the like, a pair of support shafts 33A and 33B extending in a direction orthogonal to the ball screw 27 are inserted into the moving base 29, and the tip ends of these support shafts 33A and 33B The ultrasonic probe 4 is attached to the first through a biaxial gimbal 34. Further, compression springs 35A and 35B are attached to the support shafts 33A and 33B, and the ultrasonic probe 4 is moved to the mother tube 1 side (the lower side in FIGS. 3 and 5 by the urging force of the compression springs 35A and 35B. ). The biaxial gimbal 34 is known as this type, and can swing in the circumferential direction (up and down direction in FIG. 4) and the substantially radial direction (left and right direction in FIG. 4) of the branch pipe 2. The tentacle 4 is made to follow the surface shape of the mother pipe 2 to some extent.

  The ultrasonic probe 4 is, for example, an oblique probe, and is directed toward the mother tube 1 (lower side in FIG. 1) and substantially radially inward of the branch tube 2 (left side in FIGS. 1 and 4). The ultrasonic wave is transmitted toward the receiver and the reflected signal is received. The ultrasonic transmission direction line A2 of the ultrasonic probe 4 is viewed from the axial direction of the branch pipe 2 as shown in FIG. 4 (in other words, when projected onto the radial section of the branch pipe 2). The axial center line of the ball screw 27 of the radial movement mechanism 10 (in other words, the scanning direction line when the ultrasonic probe 4 is scanned in the substantially radial direction of the branch tube 2) overlaps.

  As shown in FIGS. 3 and 4, the rotation shaft 36 is coaxial with each other on both outer sides in the width direction of the frame 26 of the radial movement mechanism 10 (the right side and the left side in FIG. 3, the lower side and the upper side in FIG. 4). And an auxiliary shaft 37 is provided. The portal plate 48 of the second frame 8 is provided with bearings 38A and 38B that rotatably support the rotation shaft 36 and the auxiliary shaft 37 of the frame frame 26. Thereby, the radial direction moving mechanism 10 is rotatable in the axial direction of the branch pipe 2 with respect to the second frame 8.

  As shown in FIGS. 3 and 4, the rotation mechanism 11 is accommodated in the box 24 of the second frame 8. The rotation mechanism 11 includes a worm wheel 39 fixed to the tip of the rotation shaft 36 of the frame 26, a worm 40 that rotates while meshing with the worm wheel 39, and a rotation in which the worm 40 is attached to an output shaft. And a drive motor 41. Then, the rotation shaft 36 of the frame frame 26 is driven and rotated by the rotation drive motor 41, and the auxiliary shaft 37 is driven and rotated accordingly. As a result, the radial movement mechanism 10 rotates in the axial direction of the branch pipe 2 with respect to the second frame 8. The rotation drive motor 41 is provided with an encoder 42 for detecting the rotation amount (rotation angle).

  Next, details of the guide rail 5 and the circumferential movement mechanism 7 which are the main parts of the present embodiment will be described with reference to FIGS. 6 and 7 and FIG. 2 described above. 6 is a cross-sectional view taken along section VI-VI in FIG. 2, and FIG. 7 is a cross-sectional view taken along section VII-VII in FIG.

  The guide rail 5 is partially shown in FIG. 6 (and FIG. 8 to be described later), but the weld line 3a is elliptical when viewed from the axial direction of the branch pipe 2 (specifically, the azimuth angle θ = 0 °). , An elliptical weld line having a minor axis at 180 ° and a major axis at azimuth angle θ = 90 ° and 270 °), and is attached to the branch pipe 2 concentrically. Yes. As shown in FIG. 2, a rack 5 a is provided over the entire circumference in the center in the width direction of the outer peripheral surface of the guide rail 5.

  As shown in FIG. 2, the circumferential movement mechanism 7 is provided with bearings on the drive traveling wheels 43 that mesh with the rack 5 a of the guide rail 5 and travel on the outer peripheral surface of the guide rail 5, and the first base plate 12 of the first frame 6. A rotating shaft 44 that is rotatably supported via (not shown) and is connected through the rotation center of the driving traveling wheel 43, and one axial side of the rotating shaft 44 from the driving traveling wheel 43 (upper side in FIG. 2). ) And is rotatably supported by the rotating shaft 44 via bearings 45A and 45B, and travels on the outer peripheral surface of the guide rail 5 (specifically, the upper portion of the rack 5a in FIG. 2). 46A is disposed on the other side in the axial direction of the driving shaft 43 on the rotating shaft 44 (upper side in FIG. 2), and is rotatably supported by the rotating shaft 44 via bearings 45C and 45D. The driven wheel 46B that travels on the outer peripheral surface of the id rail 5 (specifically, the lower part of the rack 5a in FIG. 2) and the first auxiliary plate 13 of the first frame 6 are fixed, and the output shaft is connected via a joint 47. A circumferential drive motor 48 connected to the rotary shaft 44. When the rotating shaft 44 is rotated by driving the circumferential direction drive motor 48, the driving traveling wheel 43 is driven to rotate and the driven traveling wheels 46A, 46B are driven to rotate on the outer peripheral surface of the guide rail 5, so that the first The frame 6 moves in the circumferential direction of the branch pipe 2. The circumferential drive motor 48 is provided with an encoder 49 for detecting the amount of rotation (rotation angle).

  Further, when viewed from the axial direction of the branch pipe 2 as shown in FIG. 6 (in other words, when projected onto the radial cross section of the branch pipe 2), the traveling wheels 43, 46A, The reference line D that connects the contact point of 46B and the rotation center point of the traveling wheels 43, 46A, 46B (in other words, the axis center point of the rotation shaft 44) is the ultrasonic transmission direction line of the ultrasonic probe 4 described above. It overlaps with A2 (see FIG. 4).

  2 and 6, the circumferential movement mechanism 7 is disposed on one end surface side (upper side in FIG. 2) of the guide rail 5, and the guide rail 5 is moved with respect to the traveling wheels 43, 46 </ b> A, 46 </ b> B. A pair of guide rollers 50A and 50B that are disposed on one side (lower side in FIG. 6) and the other side (upper side in FIG. 6) in the circumferential direction and run on the inner peripheral surface of the guide rail 5, and the guide rollers 50A, A pair of arms 52A, 52B for rotating the respective positions of the movable pins 51A, 51B relative to the first base plate 12 in the substantially radial direction of the branch pipe 2, and a movable pin A pair of tension springs 53 </ b> A and 53 </ b> B are provided for pulling 51 </ b> A and 51 </ b> B outward of the branch pipe 2 in the substantially radial direction. With such a configuration, the guide rollers 50A and 50B follow the inner peripheral surface of the elliptical guide rail 5.

  The arm 52A is rotatably supported on the first base plate 12 via a bearing 54A on the starting end side, and a movable pin 51A is fixed on the distal end side. Similarly, the arm 52B is rotatably supported on the first base plate 12 via a bearing 54B on the starting end side, and the movable pin 51B is fixed on the tip end side. Accordingly, the positions of the movable pins 51A and 51B (in other words, the guide rollers 50A and 50B) with respect to the first frame 6 can be rotated in the substantially radial direction of the branch pipe 2. The arms 52A and 52B have the same length dimension (specifically, the length from the axial center position of the bearing on the starting end side to the axial center position of the movable pin on the distal end side), and their rotation centers. The position and the rotation range are provided so as to be line symmetric with respect to the reference line D described above. In other words, the guide rollers 50 </ b> A and 50 </ b> B are configured so that the respective moving directions and moving ranges are symmetrical with respect to the reference line D.

  The tension spring 53A has a starting end side rotatably supported by the first base plate 12 via a fixed pin 55A, and a distal end side connected to the movable pin 51A. Similarly, the tension spring 53B is rotatably supported on the first base plate 12 via the fixed pin 55B on the start end side, and connected to the movable pin 51B on the tip end side. The guide rollers 50A and 50B are moved outward in the substantially radial direction of the branch pipe 2 by the tensile force of the tension springs 53A and 53B, and are pressed against the inner peripheral surface of the guide rail 5. The tension springs 53A and 53B have the same specifications (specifically, free length, spring constant, etc.) so that their rotational center positions on the starting side are line symmetric with respect to the reference line D. Is arranged.

  Further, as shown in FIG. 2, the circumferential movement mechanism 7 is disposed on the other end surface side (lower side in FIG. 2) of the guide rail 5, and the circumferential direction of the guide rail 5 with respect to the traveling wheels 43, 46A, and 46B. A pair of guide rollers 50C and 50D (only 50C is shown in FIG. 2) that are disposed on one side and the opposite side of the guide rail 5 and run on the inner peripheral surface of the guide rail 5, and these guide rollers 50C and 50D are rotatable. A pair of movable pins 51C, 51D (only 51C shown in FIG. 2) to be supported and a pair of arms 52C for rotating the respective positions of the movable pins 51C, 51D with respect to the second base plate 15 in the substantially radial direction of the branch pipe 2. 52D (however, only 52C is shown in FIG. 2) and a pair of tension springs 53C and 53D for pulling the movable pins 51C and 51D to the outside of the branch pipe 2 in the substantially radial direction. With such a configuration, the guide rollers 50 </ b> C and 50 </ b> D follow the inner peripheral surface of the elliptical guide rail 5.

  The arm 52C is rotatably supported on the second base plate 15 via a bearing 54C on the starting end side, and a movable pin 51C is fixed on the distal end side. Similarly, although the arm 52D is not shown, the starting end side is rotatably supported by the second base plate 15 via a bearing 54D, and the movable pin 51D is fixed to the tip end side. Accordingly, the positions of the movable pins 51C and 51D (in other words, the guide rollers 50C and 50D) with respect to the first frame 6 can be rotated in the substantially radial direction of the branch pipe 2. The arms 52C and 52D, like the arms 52A and 52B, have the same length dimension (specifically, the length from the axial center position of the bearing on the starting end side to the axial center position of the movable pin on the distal end side). These rotation center positions and rotation ranges are provided so as to be symmetric with respect to the reference line D described above. In other words, the moving directions and moving ranges of the guide rollers 50C and 50D are configured to be symmetrical with respect to the reference line D.

  The tension spring 53C has a starting end side rotatably supported by the second base plate 15 via a fixed pin 55C, and a distal end side connected to the movable pin 51C. Similarly, although not shown, the tension spring 53D is supported on the second base plate 15 so as to be rotatable via a fixed pin 55D and connected to the movable pin 51D on the distal end side. Then, the guide rollers 50C and 50D are moved substantially outward in the radial direction of the branch pipe 2 by the tensile force of the tension springs 53C and 53D, and are pressed against the inner peripheral surface of the guide rail 5. The tension springs 53C and 53D have the same specifications (specifically, free length, spring constant, etc.) as the tension springs 53A and 53B, and the rotation center position on the starting side is the reference line D. Are arranged so as to be line symmetrical.

  Then, the guide rail 5 is pinched by the three-point support of the guide rollers 50A and 50B and the driven traveling wheel 46A that hold the guide rail 5 by the tension force of the tension springs 53A and 53B, and the tension force of the tension springs 53C and 53D. The first frame 6 is positioned in the circumferential direction of the guide rail 5 by the three-point support of the guide rollers 50C and 50D and the driven traveling wheel 46B.

  The circumferential movement mechanism 7 is rotatably supported by the first base plate 12 and is disposed on one side and the opposite side of the guide rail 5 in the circumferential direction with respect to the traveling wheels 43, 46A, 46B. A pair of secondary wheels 56A and 56B that travel on one end surface of 5 and rotatably supported by the second base plate 15, and on one side and the opposite side of the guide rail 5 in the circumferential direction with respect to the traveling wheels 43, 46A, and 46B, respectively. A pair of secondary wheels 56 </ b> C and 56 </ b> D that are disposed and run on the other end surface of the guide rail 5 are provided. And the follower wheel 56A. Positioning of the first frame 6 in the axial direction of the guide rail 5 is performed by 56B and the follower wheels 56C and 56D.

  As shown in FIG. 7, a slit 5b is formed at a position of the azimuth angle θ = 0 ° in the guide rail 5, and a proximity sensor 57 for detecting the slit 5b is provided in the first base plate 12. ing.

  By the way, as described above, when viewed from the axial direction of the branch pipe 2, the weld line 3a has a short diameter at an azimuth angle θ = 0 °, 180 °, and a long diameter at an azimuth angle θ = 90 °, 270 °. It is elliptical. Therefore, at azimuth angles other than θ = 0 °, 90 °, 180 °, and 270 °, the azimuth direction line B and a direction line perpendicular to the elliptical weld line 3a (specifically, a predetermined value in the elliptical weld line 3a). An angle difference occurs between the tangent line having the position of the contact point and a vertical line (C) having the predetermined position as an intersection, and the angle difference also varies according to the azimuth angle θ. Therefore, when the circumferential movement mechanism 7 described above is viewed from the axial direction of the branch pipe 2, the reference line D (that is, the ultrasonic transmission direction line A2 of the ultrasonic probe 4) is an elliptical weld line 3a. The posture angle θp of the first frame 6 with respect to the guide rail 5 is automatically adjusted according to the movement position (azimuth angle θ) of the first frame 6 so as to substantially overlap the perpendicular direction line C with respect to. Details thereof will be described with reference to FIG.

  For example, as shown in FIG. 8, when the first frame 6 (specifically, the position of the contact point of the traveling wheels 43, 46A, 46B on the outer peripheral surface of the guide rail 5) is located at the azimuth angle θ = 50 °, the traveling wheel The curvature differs between one side and the other side in the circumferential direction of the guide rail 5 with respect to 43, 46A, 46B, the positional relationship between the guide roller 50A and the guide roller 50B with respect to the azimuth direction line B, and the position of the guide roller 50C and the guide roller 50D. The relationship is not line symmetric. At this time, with the contact point of the driven wheel 46A on the outer peripheral surface of the guide rail 5 as a fulcrum, a clockwise rotational moment M1 in the figure by the tension force F1 of the tension spring 53A acting on the fixed pin 55A (the following formula (1) And a counterclockwise rotational moment M2 (see the following formula (2)) is generated by the tensile force F2 of the tension spring 53B acting on the fixing pin 55B.

M1 = F1 ′ × L = F1 × sin α1 × L (1)
M2 = F2 ′ × L = F2 × sin α2 × L (2)
F1 ′: Moment load acting on the fixing pin 55A F2 ′: Moment load acting on the fixing pin 55B L: Contact point of the follower wheel 46A on the guide rail 5 when projected on the radial cross section of the branch pipe 2 and the fixing pin 55A Distance from the shaft center point of 55B α1: Rotation angle of the tension spring 53A α2: Rotation angle of the tension spring 53B Similarly, although not shown, the contact point of the driven wheel 46B on the outer peripheral surface of the guide rail 5 is a fulcrum and fixed A clockwise rotational moment M3 (see the following formula (3)) is generated by the tensile force F3 of the tension spring 53C acting on the pin 55C, and a counterclockwise rotation is performed by the tensile force F4 of the tension spring 53D acting on the fixed pin 55D. A moment M4 (see the following formula (4)) is generated.

M3 = F3 ′ × L = F3 × sin α3 × L (3)
M4 = F4 ′ × L = F4 × sin α4 × L (4)
F3 ′: Moment load acting on the fixing pin 55C F4 ′: Moment load acting on the fixing pin 55D L: Contact point of the follower wheel 46B on the guide rail 5 when projected on the radial cross section of the branch pipe 2 and the fixing pin 55C 55D Distance from the shaft center point α3: Rotation angle of the tension spring 53C α4: Rotation angle of the tension spring 53D And the positional relationship between the guide roller 50A and the guide roller 50B is not line symmetric with respect to the azimuth direction line B The tension spring 53A and the tension spring 53B have different expansion / contraction lengths, different tensile forces F1 and F2, and different rotation angles α1 and α2. Similarly, since the positional relationship between the guide roller 50C and the guide roller 50D is not line symmetric with respect to the azimuth direction line B, the tension spring 53C and the tension spring 53D have different expansion / contraction lengths and different tension forces F3 and F4. At the same time, the rotation angles α3 and α4 are different. Therefore, the attitude angle θp of the first frame 6 with respect to the guide rail 5 changes until the rotational moment M1 and the rotational moment M2 are balanced and the rotational moment M3 and the rotational moment M4 are balanced. As a result, when viewed from the axial direction of the branch pipe 2, the reference line D (that is, the ultrasonic transmission direction line A2 of the ultrasonic probe 4) substantially overlaps the perpendicular direction line C with respect to the elliptical weld line 3a. It is like that.

  As described above, in the present embodiment, the ultrasonic transmission direction line A2 of the ultrasonic probe 4 can be brought close to the perpendicular direction line C with respect to the welding line 3a according to the azimuth angle θ, and the flaw detection accuracy is improved. be able to.

  Further, in the present embodiment, the rotating mechanism 11 rotates the radial movement mechanism 11 with respect to the second frame 8 in the axial direction of the branch tube 2, and the ultrasonic probe 4 is moved substantially in the radial direction of the branch tube 2. The scanning angle when moving (scanning) can be adjusted. Therefore, the ultrasonic probe 4 can be positioned on the surface of the mother tube 1 according to the azimuth angle θ, and the scanning performance can be improved.

  Next, a control system of the pipe inspection apparatus of this embodiment will be described. FIG. 9 is a block diagram showing a functional configuration of the control system.

  As shown in FIG. 9 and FIG. 1 described above, the control system of the pipe inspection apparatus is wired to the movement controller 60 that drives and controls the motors 18, 31, 41, and 48 described above and the ultrasonic probe 4. The ultrasonic flaw detector 61, and the movement controller 60 and the controller 62 connected to the ultrasonic flaw detector 61 by wiring.

  The movement controller 60 receives a detection signal from the encoder 49 of the circumferential direction moving mechanism 7, and a circumferential direction driving amplifier 63 that drives and controls the circumferential direction driving motor 48 according to a command signal from the controller 62. A detection signal from the encoder 42 of the rotation drive mechanism 11 is input, and a rotation drive amplifier 64 that drives and controls the rotation drive motor 41 according to a command signal from the controller 62, and an encoder 19 of the axial movement mechanism 9. The detection signal from the encoder 32 of the radial movement mechanism 10 and the axial direction drive amplifier 65 for driving and controlling the axial direction drive motor 18 according to the command signal from the controller 62 are input. In addition, the radial direction for driving and controlling the radial direction driving motor 31 in accordance with a command signal from the controller 62 And a dynamic amplifier 66. A detection signal from the proximity sensor 57 is also input to the circumferential drive amplifier 63.

  Although not shown in detail, the ultrasonic flaw detector 61 has a pulse voltage generator and a reception amplifier. The pulse voltage generator of the ultrasonic flaw detector 61 outputs a pulse signal to the ultrasonic probe 4 according to a command signal from the controller 62, and the ultrasonic probe 4 transmits an ultrasonic wave accordingly. It is supposed to be. The reception amplifier of the ultrasonic flaw detector 61 receives the ultrasonic reflection signal received by the ultrasonic probe 4 and outputs the received ultrasonic reflection signal to the controller 62.

  The controller 62 stores the structure data of the mother pipe 1, the branch pipe 2, and the welded portion 3 in advance, and sets the flaw detection condition setting unit 67 for setting flaw detection conditions, and sets each control parameter based on the structure data and flaw detection conditions described above. A control table calculation unit 68 that generates a control table by calculation, a control table storage unit 69 that stores a control table created by the control table calculation unit 68, and a control table stored in the control table storage unit 69 A control command unit 70 that generates a command signal based on the signal and outputs it to the movement controller 60 and the ultrasonic flaw detector 61, and a data recording unit that processes the ultrasonic reflection signal input from the ultrasonic flaw detector 61 and records it as flaw detection data 71. Note that detection signals from the encoders 19, 32, 42, and 49 are input to the control command unit 70 of the controller 62.

  A control procedure in the control table creation function of the controller 62 will be described with reference to FIG. FIG. 10 is a flowchart showing the processing contents of the control table creation of the controller 62.

In FIG. 10, first, in step 100, the flaw detection condition setting unit 67 of the controller 62 sets a movement amount pitch (hereinafter referred to as a circumferential movement amount pitch) Δl of the circumferential movement mechanism 7. In step 110, the control table calculation unit 68 of the controller 62 determines the movement position (azimuth) of the first frame 6 by the circumferential movement mechanism 7 based on the circumferential movement amount pitch Δl set by the flaw detection condition setting unit 67. (Angle) θ _i (i = 0, 1, 2,..., N) is calculated (where θ ₀ = 0 °, θ _n ≈360 °). Thereafter, the process proceeds to step 120, and for each movement position θ _i of the first frame 6, the posture angle θ p _i (i = 0, 1, 2,..., N) of the first frame 6 with respect to the guide rail 5 (in detail, For example, the angle of the right-angle direction line C with respect to the elliptical weld line 3a is calculated, and further, the process proceeds to step 130, and the posture angle θp of the first frame 6 with respect to the guide rail 5 for each movement position θ _i of the first frame 6. _{Based on i} and the structure data stored in advance in the flaw detection condition setting unit 67, the sectional shape of the pipe in the scanning direction of the ultrasonic probe 4 and the center position of the welded part 3 are calculated. As a specific example, FIG. 11 and FIG. 12B show the cross-sectional shape of the pipe when the first frame 6 is located at the movement position θ _i = 90 °.

  Then, the process proceeds to step 140 where the control table calculation unit 68 generates ultrasonic waves for each moving position θi of the first frame 6 based on the cross-sectional shape of the pipe obtained in step 130 and the center position of the welded part 3. The ultrasonic wave incidence range on the surface of the mother pipe 1 is propagated to the welded part 3 (specifically, the weld metal and the heat affected zone of about 10 mm from the boundary between the weld metal and the base metal to the base metal side). Set.

Then, the process proceeds to step 150, where the control table calculation unit 68 uses the rotation mechanism 11 to move in the radial direction so that the displacement of the compression springs 35A, 35B that press the ultrasonic probe 4 against the mother tube 1 is minimized. 10 rotation angles φ _i (i = 0, 1, 2,..., N) are calculated (however, the rotation angle φ ₀ = 0 °, which is perpendicular to the axial direction of the branch pipe 2). Show the correct direction). More specifically, for example, as shown in FIG. 11, the tangent to the surface of the mother pipe 1 and the radial line of the branch pipe 2 at both end positions P and R of the incident range of the ultrasonic wave obtained in step 130 described above. The angle φa _i , φb _i between (the left-right direction line in FIG. 11) is calculated, the average value thereof is calculated, and this average value is defined as the rotation angle φ _i of the radial movement mechanism 10 by the rotation mechanism 11. Set. Note that an angle between a tangent to the surface of the mother pipe 1 and a radial line of the branch pipe 2 may be calculated at an intermediate position Q in the ultrasonic incident range, and this may be set as the rotation angle φ _i. . For each movement position θ _i of the first frame 6, the rotation angle φ _i-1 of the radial movement mechanism 10 at the previous movement position θ _i-1 of the first frame 6 and the current movement of the first frame 6. position θ difference between rotation angles phi _i of the radial moving mechanism 10 in the _i (rotation angle _{variation) Δφ i (i = 1,2,} ..., n) computes the.

Then, the process proceeds to step 160, where the control table calculation unit 68 determines the incident position of the ultrasonic wave on the surface of the mother tube 1 and the axis of the ball screw 27 of the radial movement mechanism 10 for each movement position θ _i of the first frame 6. The movement position of the second frame 8 by the axial movement mechanism 9 (hereinafter referred to as the axial movement position) d so that the minimum value of the distance to the core line is equal to the distance when the azimuth angle θ ₀ = 0 ° _i (i = 0, 1, 2,..., n) is calculated (however, the axial movement position d ₀ is a predetermined set value). More specifically, for example, as shown in FIG. 11, the intermediate position Q of the ultrasonic incident range obtained in the above-described step 130 (in other words, the inclination angle of the ultrasonic probe 4 by the biaxial gimbal 34) distance h _i is the azimuth angle of the rotation angle is approximately equal position) the axis line of the ball screw 27 in the radial direction moving mechanism 10 (shown in FIG. 11 the dotted line) in the radial direction moving mechanism 10 by the rotation mechanism 11 The axial movement position d _i of the second frame 8 is calculated so as to be equal to the distance h ₀ (see FIG. 12A) in the case of θ ₀ = 0 °. Then, for each movement position θ _i of the first frame 6, the axial movement position d _i−1 of the second frame 8 at the previous movement position θ _i−1 of the first frame 6 and the current movement of the first frame 6. position θ difference between the axial movement position _{d i} of the second frame 8 in _i (axial movement _{variation) Δd i (i = 1,2,} ..., n) computes the.

Then, the process proceeds to step 170, where the control table calculation unit 68 moves the moving range (hereinafter referred to as a scanning range) pa of the ultrasonic probe 4 by the radial moving mechanism 10 for each moving position θ _i of the first frame 6. _i , pb _i (i = 0, 1, 2,..., n) are calculated. More specifically, for example, as indicated by a one-dot chain line in FIG. 11, the ball of the radial movement mechanism 10 passes through each of the both end positions P and R of the ultrasonic wave incident range obtained in step 130 described above. A vertical line with respect to the axial line of the screw 27 is drawn, and the intersection of the axial line of the ball screw 27 and the vertical line is set as a scanning start position pa _i and a scanning end position pb _i . Further, it calculates a difference (scanning distance) Delta] p _i of the scanning start position pa _i and the scanning end position pb _i. The scan start position pa _i and the scan end position pb _i are preferably set to be different for each movement position θ _i of the first frame 6, but may be set to be the same.

Then, the process proceeds to step 180, and as shown in FIG. 13, as a control table, for each movement position θ _i of the first frame 6, a circumferential movement amount pitch Δl, a rotation angle change amount Δφ _i , and an axial direction movement change amount Δd. _i , the scanning ranges pa _i and pb _i, and the scanning distance Δp _i are stored (stored) in the control table storage unit 69.

  The control command unit 70 of the controller 62 outputs a movement command signal to the movement controller 60 based on the control table stored in the control table storage unit 63 and outputs an ultrasonic transmission command signal to the ultrasonic flaw detector 61. It is supposed to be. A control procedure in such a flaw detection control function of the controller 62 will be described with reference to FIG. FIG. 14 is a flowchart showing the processing contents of the flaw detection control of the controller 62.

In FIG. 14, first, for example, when an initial position setting command is input, in step 200, the control command unit 70 of the controller 62 sends the initial position command signal to the circumferential drive amplifier 63 of the movement controller 60, and the rotation. This is output to the driving amplifier 64 and the axial driving amplifier 65. As a result, the circumferential drive amplifier 63 drives the circumferential drive motor 48 to the first position until the slit 5b of the guide rail 5 is detected by the proximity sensor 57 (that is, the azimuth angle θ ₀ = 0 °). The frame 6 is moved. The rotation drive amplifier 64 drives the rotation drive motor 41 to rotate the radial movement mechanism 10 to the rotation angle φ ₀ = 0 °. Further, the axial driving amplifier 65 drives the axial drive motor 18 to move the second frame 8 to a predetermined axial displacement position d _0. In addition, regarding the predetermined axial movement position d ₀ , after the azimuth angle θ ₀ = 0 ° and the rotation angle φ ₀ = 0 ° are set, the setting may be changed manually by an operator. In step 210, identifier i = 0 (initial value) is set.

For example, when a flaw detection inspection start command is input, the process proceeds to step 220, and the control command unit 70 of the controller 62 sets the scan start position pa ₀ stored in the control table storage unit 69 because the identifier i = 0. The command signal (command pulse) for reading and scanning start position pa ₀ is output to radial drive amplifier 66 of movement controller 60. As a result, the radial drive amplifier 66 drives the radial drive motor 31 (specifically, drives until the number of detected pulses of the encoder 32 is equal to the number of command pulses) until the scan start position pa _0. The ultrasonic probe 4 is moved. Thereafter, the process proceeds to step 230, the control instruction unit 70 of the controller 62, since the identifier i = 0, reads the scanning end position pb ₀ stored in the control table storage unit 69, a command signal of the scanning end position Pb ₀ ( Command pulse) is output to the radial drive amplifier 66 of the movement controller 60 and an ultrasonic transmission command signal is output to the ultrasonic flaw detector 61. As a result, the radial drive amplifier 66 drives the radial drive motor 31 (specifically, it drives until the number of detected pulses of the encoder 32 is equal to the command pulse number), and reaches the scanning end position pb _0. The ultrasonic probe 4 is moved. At the same time, the ultrasonic flaw detector 61 transmits an ultrasonic wave to the ultrasonic probe 4, receives an ultrasonic reflection signal received by the ultrasonic probe 4, and receives the received ultrasonic reflection signal. Is output to the data recording unit 71 of the controller 62. The data recording unit 71 of the controller 62 processes the ultrasonic reflection signal input from the ultrasonic flaw detector 61 and records it as flaw detection data. The flaw detection data includes position information of the ultrasonic probe 4 (specifically, at least the moving position θ _i of the first frame 6 and the moving position of the ultrasonic probe 4 by the radial direction moving mechanism 10). ing. The control command unit 70 of the controller 62 outputs an ultrasonic stop command signal to the ultrasonic flaw detector 61 when the ultrasonic probe 4 moves to the scanning end position pb ₀ . As a result, the ultrasonic flaw detector 61 causes the ultrasonic probe 4 to stop transmitting ultrasonic waves.

In step 240, the control command unit 70 of the controller 62 determines whether or not the identifier i = n (in other words, whether or not the flaw detection inspection is completed). At first, since the determination in step 240 is not satisfied, the process proceeds to step 250. In step 250, the identifier i = i + 1 = 1 is calculated. Then, the process proceeds to step 260, and the control command unit 70 of the controller 62 has the identifier i = 1, so that the circumferential movement amount pitch Δl, the rotation angle change amount Δφ ₁ and the axis stored in the control table storage unit 69 are determined. The direction movement change amount Δd ₁ is read. Then, a command signal (command pulse) of the circumferential movement amount pitch Δl is output to the circumferential drive amplifier 63 of the movement controller 60, and a command signal (command pulse) of the rotation angle change amount Δφ ₁ is output to the movement controller 60. To the rotational drive amplifier 64, and a command signal for the axial movement change amount Δd ₁ is output to the axial drive amplifier 65 of the movement controller 60. As a result, the circumferential drive amplifier 63 drives the circumferential drive motor 48 (specifically, it is driven until the number of detected pulses of the encoder 49 is the same as the command pulse number), and the _first drive up to the azimuth angle θ1. One frame 6 is moved. Further, the rotational drive amplifier 64 drives the rotational drive motor 42 (specifically, it is driven until the number of detected pulses of the encoder 41 is the same as the command pulse number), and moves in the radial direction to the rotational angle φ _1. The mechanism 10 is rotated. Also, the axial drive amplifier 65 drives the axial drive motor 18 (specifically, it drives until the number of detected pulses of the encoder 19 is equal to the command pulse number), and reaches the axial movement value d _1. The second frame 9 is moved.

Then, the process returns to step 220 described above, the control instruction unit 70 of the controller 62, since the identifier i = 1, reads the scan start position pa ₁ stored in the control table storage unit 69, a command of the scan start position pa ₁ The signal is output to the radial drive amplifier 66 of the movement controller 60. As a result, the radial driving amplifier 66 drives the radial driving motor 31 to move the ultrasonic probe 4 to the scanning start position pa ₁ . Thereafter, the process proceeds to step 230, and since the control command unit 70 of the controller 62 has the identifier i = 1, the scan end position pb ₁ stored in the control table storage unit 69 is read and a command signal for the scan end position Pb ₁ is read. While outputting to the radial direction driving amplifier 66 of the movement controller 60, an ultrasonic transmission command signal is output to the ultrasonic flaw detector 61. As a result, the radial driving amplifier 66 drives the radial driving motor 31 to move the ultrasonic probe 4 to the scanning end position pb ₁ . At the same time, the ultrasonic flaw detector 61 transmits an ultrasonic wave to the ultrasonic probe 4, receives an ultrasonic reflection signal received by the ultrasonic probe 4, and receives the received ultrasonic reflection signal. Is output to the data recording unit 71 of the controller 62.

  The above-described steps 250, 260, 220, and 230 are repeated until the determination of step 240 is satisfied. When the identifier i = n and the determination in step 240 is satisfied, the flaw detection control ends.

  In the present embodiment configured as described above, the ultrasonic probe is set while the ultrasonic transmission direction line A2 of the ultrasonic probe 4 is brought close to the perpendicular direction line C with respect to the welding line 3a according to the azimuth angle θ. 4 can be positioned on the surface of the mother tube 1 and the ultrasonic probe 4 can be automatically scanned. Therefore, the flaw detection inspection can be performed efficiently while improving the flaw detection accuracy.

  Next, another embodiment of the present invention will be described with reference to FIGS. In the present embodiment, a slider is provided in place of the arms 52A to 52D. In the present embodiment, the same parts as those in the above-described embodiment are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

  15 is a side view showing the detailed structure of the guide rail and the circumferential movement mechanism in the present embodiment, and FIG. 16 is a sectional view taken along section XVI-XVI in FIG. 15 (note that the first frame and the circumference). This shows the case where the direction moving mechanism is located at the azimuth angle θ = 0 °).

  In the present embodiment, the circumferential movement mechanism 80 includes a pair of guide rollers 50A and 50B, movable pins 81A and 81B that rotatably support the guide rollers 50A and 50B, and movable pins 81A and 81B for the first base plate 82. The pair of sliders 83A and 83B slide the respective positions in the substantially radial direction of the branch pipe 2, and the pair of tension springs 53A and 53B that pull the movable pins 81A and 81B outward in the substantially radial direction of the branch pipe 2. ing. With such a configuration, the guide rollers 50A and 50B follow the inner peripheral surface of the elliptical guide rail 5.

  The first base plate 82 is formed with a pair of slide grooves 82a and 82b extending substantially in the radial direction of the branch pipe 2. The slider 83A is slidably supported by a pair of linear guides 84A and 84B provided on both sides of the slide groove 82a of the first base plate 82, and these linear guides 84A and 84B. The slider 83A is supported by the slide groove 82a of the first base plate 82. The slider plate 85A supports the inserted movable pin 81A. Similarly, the slider 83B is slidably supported by a pair of linear guides 84C and 84D provided on both sides of the slide groove 82b of the first base plate 82, and these linear guides 84C and 84D. The slider plate 85B supports the movable pin 81B inserted through the groove 82b. The sliding grooves 82a and 82b and the sliders 83A and 83B of the first base plate 82 are symmetrical with respect to the reference line D in the moving direction and moving range of the movable pins 81A and 81B (that is, the guide rollers 50A and 50B). It is comprised so that.

  The tension spring 53A has a starting end side rotatably supported by the first base plate 82 via a fixed pin 55A, and a distal end side connected to the movable pin 81A. Similarly, the tension spring 53B is supported on the first base plate 82 by the first base plate 82 so as to be rotatable via a fixed pin 55B, and the distal end side is connected to the movable pin 81B. The guide rollers 50A and 50B are moved outward in the substantially radial direction of the branch pipe 2 by the tensile force of the tension springs 53A and 53B, and are pressed against the inner peripheral surface of the guide rail 5. The tension springs 53 </ b> A and 53 </ b> B have the same specifications and are arranged so that their rotation center positions are line-symmetric with respect to the reference line D.

  The circumferential movement mechanism 7A includes a pair of guide rollers 50C and 50D (only 50C shown in FIG. 15) and movable pins 81C and 81D (see FIG. 15) that rotatably support the guide rollers 50C and 50D. Only the middle 81C), sliders 83C and 83D for sliding the positions of the movable pins 81C and 81D with respect to the second base plate 86 in the substantially radial direction of the branch pipe 2 (however, only 83C is shown in FIG. 15), and the movable pins There are tension springs 53C and 53D for pulling 81C and 81D to the outside of the branch pipe 2 in the substantially radial direction. With such a configuration, the guide rollers 50 </ b> C and 50 </ b> D follow the inner peripheral surface of the elliptical guide rail 5.

  The second base plate 86 is formed with a pair of slide grooves 86a and 86b (only 86a is shown in FIG. 15) extending in the substantially radial direction of the branch pipe 2. The slider 83C is slidably supported by a pair of linear guides 84E and 84F (only 84E is shown in FIG. 15) provided on both sides of the slide groove 86a of the second base plate 86, and these linear guides 84E and 84F. The slider plate 85C supports the movable pin 81C inserted into the slide groove 86a of the second base plate 86. Similarly, although not shown, the slider 83D is slidably supported by a pair of linear guides 84G and 84H provided on both sides of the slide groove 86b of the second base plate 86, and these linear guides 84G and 84H. The slider plate 85D supports the movable pin 81D inserted into the slide groove 86b of the base plate 86. The slide grooves 86a and 86b and the sliders 83C and 83D of the second base plate 86 are symmetrical with respect to the reference line D in the moving direction and moving range of the movable pins 81C and 81D (that is, the guide rollers 50C and 50D). It is comprised so that.

  The tension spring 53C has a starting end side rotatably supported by the second base plate 86 via a fixed pin 55A, and a distal end side connected to the movable pin 81C. Similarly, the tension spring 53D is supported on the second base plate 86 by the second base plate 86 so as to be rotatable via the fixed pin 55B, and the distal end side is connected to the movable pin 81D. Then, the guide rollers 50C and 50D are moved substantially outward in the radial direction of the branch pipe 2 by the tensile force of the tension springs 53C and 53D, and are pressed against the inner peripheral surface of the guide rail 5. The tension springs 53C and 53D have the same specifications and are arranged so that their rotational center positions are line-symmetric with respect to the reference line D.

  Then, the guide rail 5 is pinched by the three-point support of the guide rollers 50A and 50B and the driven traveling wheel 46A that hold the guide rail 5 by the tension force of the tension springs 53A and 53B, and the tension force of the tension springs 53C and 53D. The first frame 6 is positioned in the circumferential direction of the guide rail 5 by the three-point support of the guide rollers 50C and 50D and the driven traveling wheel 46B.

  Also in the circumferential movement mechanism 80 configured as described above, the reference line D (that is, the ultrasonic probe) when viewed from the axial direction of the branch pipe 2 as in the circumferential movement mechanism 7 of the above-described embodiment. The attitude angle θp of the first frame 6 with respect to the guide rail 5 is automatically adjusted according to the movement position of the first frame 6 so that the ultrasonic transmission direction line A2) of 4 is substantially overlapped with the perpendicular direction line C with respect to the welding line 3a. It is like that. Therefore, as in the first embodiment, the ultrasonic transmission direction line A2 of the ultrasonic probe 4 can be brought close to the perpendicular direction line C with respect to the welding line 3a according to the azimuth angle θ, and the flaw detection accuracy can be improved. it can.

  In the above-described embodiment, the circumferential movement mechanisms 7 and 80 travel on the driving traveling wheel 43 and the driven traveling wheels 46 </ b> A and 46 b traveling on the outer peripheral surface of the guide rail 5 and the inner peripheral surface of the guide rail 5. Although the configuration including the pair of guide rollers 50A to 50D has been described as an example, the configuration is not limited thereto. That is, it is only necessary to include at least one traveling wheel and at least a pair of guide rollers. In such a case, the same effect as described above can be obtained.

  In the above embodiment, the control table storage unit 63 of the controller 62 has a circumferential movement amount pitch Δl, a rotation angle change amount Δφi, and an axial movement for each movement position θi of the first frame 6 as a control table. Although the case where the change amount Δdi, the scanning ranges pai and pbi, and the scanning distance Δpi are stored has been described as an example, the present invention is not limited thereto. That is, for example, for each movement position θi of the first frame 6, the rotation angle φi, the axial movement position di, the scanning ranges pai, pbi, and the scanning distance Δpi may be stored. In such a case, the same effect as described above can be obtained.

DESCRIPTION OF SYMBOLS 1 Mother pipe 2 Branch pipe 3 Welding part 3a Welding line 4 Ultrasonic probe 5 Guide rail 5b Slit 6 1st frame 7 Circumferential movement mechanism 8 Second frame 9 Axial movement mechanism 10 Radial movement mechanism 11 Rotation mechanism 43 Driving wheel (traveling wheel)
46A, 46B Followed traveling wheel (traveling wheel)
50A-50D Guide roller 51A-51D Movable pin (rotating shaft)
52A to 52D arm (roller moving mechanism, posture angle adjusting means)
53A-53D Tension spring (Attitude angle adjustment means)
57 Proximity sensor (origin position detector)
60 Movement controller (probe movement control means)
62 controller (storage means, probe movement control means, circumferential movement position calculation means, attitude angle calculation means, rotation angle / axial movement position / scanning range calculation means)
80 Circumferential movement mechanism 81A-81D Movable pin (rotary shaft)
83A to 83D slider (roller moving mechanism, attitude angle adjusting means)

Claims (7)

When the end of the branch pipe is butt welded to the outer circumference of the mother pipe so that the mother pipe and the branch pipe are almost different and perpendicular to each other, when viewed from the axial direction of the branch pipe The welded part in which the weld line has an elliptical shape is the inspection target,
Extend in the circumferential direction of the branch pipe attached to the outer periphery of said branch pipe, an annular guide rail having a raceway which is a similar figure with respect to the weld line of the elliptical shape,
At least one traveling wheel that is interposed between the guide rail and the first frame and travels on the outer peripheral surface of the guide rail, and on one side and the opposite side in the circumferential direction of the guide rail with respect to the traveling wheel A circumferential movement mechanism that has a pair of guide rollers disposed and travels on an inner circumferential surface of the guide rail, and moves the first frame in the circumferential direction of the branch pipe with respect to the guide rail;
An axial movement mechanism that is interposed between the first frame and the second frame and moves the second frame in the axial direction of the branch pipe with respect to the first frame;
A pipe inspection comprising a radial movement mechanism interposed between the second frame and the ultrasonic probe and moving the ultrasonic probe in a substantially radial direction of the branch pipe with respect to the second frame. A device,
When viewed from the axial direction of the branch pipe, the ultrasonic transmission direction line of the ultrasonic probe intersects the ultrasonic incident position with respect to a tangent line with the ultrasonic incident position in the elliptical weld line as a contact. as substantially overlap and the vertical line, have a posture angle adjusting means for automatically adjusting the attitude angles with respect to the guide rails of the first frame in accordance with the movement position of the first frame,
When viewed from the axial direction of the branch pipe, the traveling wheel has a reference line connecting the contact point of the traveling wheel and the rotation center point of the traveling wheel on the outer peripheral surface of the guide rail. It is attached to the first frame so as to overlap with the ultrasonic transmission direction line of the child,
The posture angle adjusting means is
A pair configured such that each position of the pair of guide rollers with respect to the first frame can be moved in a substantially radial direction of the branch pipe, and the moving direction and the moving range thereof are axisymmetric with respect to the reference line. A roller moving mechanism of
A pair of tension springs connected to the rotation shafts of the pair of guide rollers and having a leading end side rotatably supported by the first frame, and pulling the pair of guide rollers outward in the radial direction of the branch pipe; Have
The pipe inspection apparatus, wherein the pair of tension springs are arranged so that a rotation center position on a starting side thereof is axisymmetric with respect to the reference line . In the piping inspection device according to claim 1 ,
The pair of roller moving mechanisms have a pair of arms for rotating the respective positions of the rotation shafts of the pair of guide rollers with respect to the first frame in a substantially radial direction of the branch pipe. . In the piping inspection device according to claim 1 ,
The pair of roller moving mechanisms includes a pair of sliders for sliding the respective positions of the rotation shafts of the pair of guide rollers with respect to the first frame in a substantially radial direction of the branch pipe. In the piping inspection device according to any one of claims 1 to 3 ,
A pipe inspection apparatus comprising a rotation mechanism for rotating the radial movement mechanism in the axial direction of the branch pipe with respect to the second frame. In the piping inspection device according to claim 4 ,
As a control table, for each movement position of the first frame by the circumferential movement mechanism, a rotation angle of the radial movement mechanism by the rotation mechanism, an axial movement position of the second frame by the axial movement mechanism, And storage means for storing a scanning range of the ultrasonic probe by the radial movement mechanism;
And a probe movement control means for controlling the circumferential movement mechanism, the rotation mechanism, the axial movement mechanism, and the radial movement mechanism based on a control table stored in the storage means. Pipe inspection equipment. In the piping inspection device according to claim 5 ,
Based on a movement amount pitch of the circumferential movement mechanism, a circumferential movement position calculating means for calculating a movement position of the first frame by the circumferential movement mechanism;
Attitude angle calculation means for calculating the attitude angle of the first frame automatically adjusted by the ultrasonic wave transmission direction adjustment means for each movement position of the first frame calculated by the circumferential direction movement position calculation means;
For each moving position of the first frame calculated by the circumferential direction moving position calculating means, the attitude angle of the first frame calculated by the attitude angle calculating means and the mother pipe, the branch pipe stored in advance, And calculating the cross-sectional shape of the pipe based on the structural data of the weld, and based on the cross-sectional shape of the pipe, the rotation angle of the radial movement mechanism by the rotation mechanism, the second frame of the second frame by the axial movement mechanism A rotation angle / axial movement position / scanning range calculation means for calculating an axial movement position and a scanning range of the ultrasonic probe by the radial movement mechanism;
The storage means, as a control table, for each movement position of the first frame calculated by the circumferential movement position calculation means, the radius calculated by the rotation angle / axial movement position / scanning range calculation means. A piping inspection apparatus that stores a rotation angle of a direction moving mechanism, an axial movement position of the second frame, and a scanning range of the ultrasonic probe. In the piping inspection device according to claim 5 or 6 ,
A slit is formed at a predetermined circumferential position of the guide rail,
A piping inspection apparatus, wherein an origin position detector for detecting a position of a slit of the guide rail is provided in the first frame as an origin of a movement position of the first frame by the circumferential movement mechanism.

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