JP2015045536A - Small-diameter pipe inspection device and inspection method for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inspection device capable of efficiently and precisely inspecting a small-diameter pipe.SOLUTION: A small-diameter pipe inspection device inspecting a small-diameter pipe includes: a first ultrasonic flaw detection device having a plurality of transducers 7 disposed over the circumferential direction on the outer circumferential face of the pipe, emitting ultrasonic waves to the axial direction of the pipe from the respective transducers 7, and receiving reflection waves thereof to specify a range in which a flaw is present in the pipe; and a second ultrasonic flaw detection device having a plurality of transducers disposed in one or more lines, controlling ultrasonic transmission timing of the respective transducers emitted in the thickness direction from outside the pipe to converge an ultrasonic wave to an arbitrary position, and receiving the reflection wave thereof to detect the flaw of the pipe.

Description

  The present invention relates to an inspection apparatus for inspecting small-diameter piping using an ultrasonic probe, and a method thereof.

  In various facilities such as chemical factories, manufacturing plants, power plants, etc., many small-diameter pipes with an outer diameter of 750 mm or less are installed. May occur. Then, in order to confirm the soundness of piping, the inner surface inspection of piping is performed using visual observation, a fiber scope, etc. (refer patent document 1).

  However, in the inspection method performed visually or using a fiberscope, it is difficult to accurately grasp the defect position and defect status, and the flange portion (connecting portion) of the pipe must be removed. There is a problem that it takes time for the subsequent mounting work, and further, the work for confirming the sealing performance at the flange portion. Further, when the flange portion is removed and attached, new defects may occur in the lining as a corrosion-resistant material covering the inner surface of the pipe and the packing as a seal member.

  On the other hand, as a method that does not require removing the flange portion, there is a method using ultrasonic waves. For example, Patent Document 2 proposes a method of inspecting lining peeling and the like by emitting ultrasonic waves in the thickness direction from the outside of a pipe and receiving the reflected waves.

JP 2012-163707 A JP 2003-130854 A

  However, since the ultrasonic flaw detection apparatus described in Patent Document 2 does not have a very wide range of inspection at a time, it takes a long time to efficiently and accurately check a small-diameter pipe installed long in the axial direction. There was a problem that inspection cost became high.

  Therefore, the present invention has been proposed in view of the above-described problems, and an object of the present invention is to provide an inspection apparatus and method capable of efficiently and accurately inspecting a small-diameter pipe. It is in.

  The invention of claim 1 is a small-diameter pipe inspection device for inspecting small-diameter pipes, and has a plurality of vibrators arranged in the circumferential direction on the outer peripheral surface of the pipe, and pipes from each vibrator. A first ultrasonic flaw detector that emits ultrasonic waves in the axial direction and receives the reflected waves to identify the range in which there is a defect in the pipe, and a plurality of transducers arranged in one or more rows. In the range specified by the first ultrasonic flaw detector, the ultrasonic transmission timing of each transducer emitted in the thickness direction from the outside of the pipe is controlled to converge the ultrasonic wave at an arbitrary position, And a second ultrasonic flaw detector that receives the reflected wave and performs flaw detection on the pipe.

  By using the first ultrasonic flaw detector and emitting an ultrasonic wave in the axial direction of the pipe and receiving the reflected wave, it is possible to roughly specify a range where the pipe has a defect. Then, in the range specified by the first ultrasonic flaw detector, the second ultrasonic flaw detector is used to converge the ultrasonic wave at an arbitrary position of the pipe and to receive the reflected wave, thereby existing in the pipe. It is possible to accurately specify the size and position of the defect to be performed.

  According to a second aspect of the present invention, in the small-bore pipe inspection device according to the first aspect, the vibrator included in the second ultrasonic flaw detector includes a vibrator that only transmits ultrasonic waves, and only receives ultrasonic waves. It is configured separately from the vibrator that performs the above.

  By configuring the vibrator of the second ultrasonic flaw detector into a vibrator that only transmits ultrasonic waves and a vibrator that only receives ultrasonic waves, inspection in small-diameter piping can be performed accurately. Can be done well. That is, even if the distance from the position of the transducer to the reflection target such as a defect is very short and the timing at which the reflected wave returns is early, it is not disturbed by the transmitted ultrasonic wave, The reflected wave can be received well by the vibrator.

  According to a third aspect of the present invention, in the small-bore pipe inspection device according to the second aspect, the ultrasonic transmission direction of the vibrator that only transmits the ultrasonic waves and the ultrasonic wave of the vibrator that only receives the ultrasonic waves The reception directions are diagonal to each other.

  Realizing a shorter focus by making the ultrasonic transmission direction of the transducer that performs only ultrasonic transmission and the ultrasonic reception direction of the transducer that performs only reception of ultrasonic waves oblique to each other. It is possible to detect a defect at a particularly shallow position.

  According to a fourth aspect of the present invention, in the small-bore pipe inspection device according to any one of the first to third aspects, the contact surface of the second ultrasonic flaw detector with respect to the outer peripheral surface of the pipe is the ultrasonic convergence. A concave curved surface is formed in a direction parallel to the incident angle changing direction of the beam.

  By forming the contact surface in this way, when the second ultrasonic flaw detector is arranged so that the incident angle change direction of the ultrasonic convergent beam is orthogonal to the axial direction of the pipe, the contact surface is It can be stably brought into contact with the outer peripheral surface of the pipe, and the detection accuracy is improved.

  According to a fifth aspect of the present invention, in the small-bore pipe inspection device according to any one of the first to third aspects, the contact surface of the second ultrasonic flaw detector with respect to the outer peripheral surface of the pipe is the ultrasonic convergence. A concave curved surface is formed in a direction perpendicular to the beam incident angle changing direction.

  By forming the contact surface in this way, when the second ultrasonic flaw detector is arranged so that the incident angle change direction of the ultrasonic convergent beam is orthogonal to the circumferential direction of the pipe, the contact surface is It can be stably brought into contact with the outer peripheral surface of the pipe, and the detection accuracy is improved.

  The invention of claim 6 is a small-diameter pipe inspection method for inspecting a small-diameter pipe, wherein a plurality of vibrators are arranged in the circumferential direction on the outer peripheral surface of the pipe, and from each vibrator to the axial direction of the pipe. A first ultrasonic flaw detection process that generates an ultrasonic wave, receives a reflected wave thereof, and identifies a range in which a defect exists in the piping, and in a range specified in the first ultrasonic flaw detection process, in one or more rows By controlling the ultrasonic transmission timing emitted from the outside of the pipe in the thickness direction of a plurality of arranged transducers, the ultrasonic focused beam is converged to an arbitrary position, and the reflected wave is received to the pipe. And a second ultrasonic flaw detection step for performing flaw detection.

  By emitting ultrasonic waves in the axial direction of the pipe and receiving the reflected waves by the first ultrasonic flaw detection process, it is possible to roughly specify the range where the pipe has a defect. Then, in the second ultrasonic flaw detection process, the ultrasonic wave is converged to an arbitrary position of the pipe in the range specified by the first ultrasonic flaw detector, and the reflected wave is received, thereby existing in the pipe. The size and position of the defect can be specified accurately.

  According to the present invention, the first ultrasonic flaw detector (first ultrasonic flaw detection process) roughly specifies the range in which piping defects exist, and then the second ultrasonic flaw detector (second flaw detector). In the ultrasonic flaw detection process), the size and position of the defect can be accurately specified within the range specified by the first ultrasonic flaw detection apparatus, so that the inspection can be performed efficiently and accurately. .

It is a block diagram of the 1st ultrasonic flaw detector with which the inspection apparatus which concerns on this invention is provided. It is a figure which shows the state which attached the 1st ultrasonic flaw detector to piping. (A) is the figure which shows the attachment position of the 1st ultrasonic flaw detector to piping, and the position of the thinning part which exists in piping, (B) is the reflected wave signal over the axial direction and circumferential direction of piping. The figure which shows distribution and signal strength, (C) is a figure which shows the intensity | strength of the reflected wave signal over the axial direction of piping. It is a block diagram of the 2nd ultrasonic flaw detector with which the inspection apparatus which concerns on this invention is provided, Comprising: It is the figure which looked at the 2nd ultrasonic flaw detector from the left or the right direction. It is the figure which looked at the 2nd ultrasonic flaw detector from front or back. It is a top view of the vibrator with which the 2nd ultrasonic inspection device is provided. It is a figure which shows the angle which can change an ultrasonic convergence beam. It is a figure which shows the focal distance which can converge an ultrasonic convergence beam. (A) is a figure which shows the state which has arrange | positioned the 2nd ultrasonic flaw detector to piping with which the conical hole part was formed in the internal peripheral surface, (B) is using the 2nd ultrasonic flaw detector. It is a figure which shows an example of the reflected signal displayed when inspecting. (A) is a view showing a focus type vertical probe, (B) is a view showing a split type vertical probe, and (C) is a view showing a general-purpose probe. It is a figure which shows the result of the experiment which investigates each detectable range of this embodiment and the probe shown in FIG. It is a figure which shows operation in the case of moving a phased array flaw detection sensor to a pipe-axis direction, and shifting to the circumferential direction. It is a figure which shows operation in the case of moving a phased array flaw detection sensor to a pipe circumferential direction, and shifting to an axial direction. It is a figure which shows the specific range in case the some defect is located close to the circumferential direction. It is a figure which shows embodiment which formed the contact surface with the piping of a wedge in the shape of a concave curved surface. It is a figure which shows embodiment which formed the contact surface of the wedge in the shape orthogonal to FIG. It is a table | surface which shows an example of the time required for each inspection with the inspection method which concerns on this invention, and the case where it checks using only a general purpose type probe.

Hereinafter, the small-diameter pipe inspection apparatus and method according to the present invention will be described.
The small-diameter pipe to which the inspection device and the inspection method according to the present invention are applied refers to a pipe having an outer diameter of 750 mm or less.

FIG. 1 is a configuration diagram of a first ultrasonic flaw detector provided in an inspection apparatus according to the present invention.
As shown in FIG. 1, the first ultrasonic flaw detector 1 includes a pair of split ring flaw sensors 2A and 2B formed in a semicircular shape, a transmission / reception unit 3, an arithmetic processing unit 4, and a storage unit 5. And a display unit 6.

  A plurality of vibrators 7 are arranged in the circumferential direction on the inner peripheral surface of each split ring flaw detection sensor 2A, AB. In addition, one split ring flaw detection sensor 2B is provided with a fixture 8 that is assembled and fixed to the other split ring flaw detection sensor 2A. The fixture 8 has a frame body 9 rotatably attached to both end portions of one split ring flaw detection sensor 2B, and a presser screw 10 attached to the frame body 9.

  As shown in FIG. 2, in order to attach and fix the pair of split ring flaw detection sensors 2A and 2B to the small-diameter pipe 11, first, the pair of split ring flaw detection sensors 2A and 2B are arranged so as to sandwich the pipe 11 from the outer periphery. . Next, the frame body 9 is rotated to move the holding screw 10 onto the end of the other divided ring flaw detection sensor 2A, and the holding screw 10 is rotated so that both divided ring flaw detection sensors 2A and 2B are connected to the outer peripheral surface of the pipe. It is pressed against and fixed.

  Each split ring flaw detection sensor 2A, 2B is connected to the transmission / reception unit 3 with a cable or the like, and when current is applied from the transmission / reception unit 3 with both the split ring flaw detection sensors 2A, 2B fixed to the pipe 11. The plurality of vibrators 7 vibrate to generate ultrasonic waves all around the pipe 11. The ultrasonic wave generated here is a so-called guide wave that propagates in the axial direction of the pipe 11. Each transducer 7 detects the reflected wave of the guide wave and outputs it to the transmitting / receiving unit 3.

  The arithmetic processing unit 4 processes the reflected wave signal received by the transmitting / receiving unit 3 and transmits the processed data to the storage unit 5 and the display unit 6. The storage unit 5 stores the processing data, and the display unit 6 can output and display the processing data as an image. The arithmetic processing unit 4, the storage unit 5, and the display unit 6 are, for example, personal computers.

FIG. 3 shows an example of a reflected wave signal displayed when an inspection is performed using the first ultrasonic flaw detector.
Here, as shown in FIG. 3 (A), a pair of split ring flaw detection sensors 2A and 2B are set in a pipe 11 where a thinned portion exists at the locations (a) to (f), and the split ring flaw detection sensor 2A is set. , 2B, guide waves were propagated toward the flanges 11a, 11b on both ends of the pipe 11. As a result, a reflected wave signal as shown in FIGS. 3B and 3C was obtained. 3B shows the distribution and signal intensity of the reflected wave signal in the axial direction and the circumferential direction of the pipe, and FIG. 3C shows the intensity of the reflected wave signal in the axial direction of the pipe. In addition, (a)-(f) in FIG.3 (B) (C) respond | corresponds to the thinning part (a)-(f) in FIG. 3 (A). Thus, according to the first ultrasonic flaw detector, it is possible to identify the circumferential position and the axial position of the thinned portion by confirming the location where the reflected wave signal intensity is high.

FIG. 4 is a configuration diagram of a second ultrasonic flaw detector provided in the inspection device according to the present invention.
As shown in FIG. 4, the second ultrasonic flaw detector 12 includes a phased array flaw detection sensor 13, a transmission / reception unit 14, a calculation processing unit 15, a storage unit 16, and a display unit 17.

  The phased array flaw detection sensor 13 includes a transmission side probe 18 that only transmits ultrasonic waves, a reception side probe 19 that only receives ultrasonic waves (reflected waves), a transmission side probe 18 and a reception side. The probe 19 is composed of a pair of wedges 20 and 21 holding the upper surfaces 20a and 21a. The transmission side probe 18 and the reception side probe 19 have a plurality of transducers 22 and 23, respectively. In general, the probe includes a linear array probe having a structure in which transducers are arranged in a row and a matrix array probe having a structure in which transducers are arranged in two or more rows. A matrix array probe is used. However, the present invention does not exclude the application of the linear array probe.

  Specifically, the transducers 22 and 23 included in the probes 18 and 19 are arranged in two rows when viewed from the left or right direction shown in FIG. 4, and 16 pieces when viewed from the front or rear direction shown in FIG. They are arranged side by side. That is, as shown in the plan view of FIG. 6, the transducers 22 and 23 provided in the transmission side probe 18 and the reception side probe 19 each have a total of 32 vibrations of 2 rows × 16 rows. A child group is formed. The sizes of the vibrators 22 and 23 used in this embodiment are 0.5 mm in length and 1.9 mm in width in FIG. 6, and are arranged at a pitch of 0.1 mm in the vertical and horizontal directions.

  By controlling the ultrasonic transmission timing of each transducer 22, 23 by arranging the transducers 22, 23 as described above, the ultrasonic waves can be converged at an arbitrary position in the thickness direction of the pipe. The focal point of the ultrasonic focused beam can be changed to an arbitrary position in the left-right direction. In this embodiment, as shown in FIG. 7, the ultrasonic focused beam can be changed to 45 ° at 1 ° pitch in both the left and right directions. In the present embodiment, the upper surface 20a, 21a of each wedge 20, 21 is an inclined surface that is inclined in the front-rear direction (lateral direction in FIG. 4), so that the ultrasonic transmission direction of the transmitting probe 18 is transmitted. And the ultrasonic wave receiving direction of the receiving side probe 19 are inclined with respect to each other. Thereby, as shown in FIG. 8, even if it is a short focal distance of 3 mm in depth from the outer peripheral surface of the piping 11, an ultrasonic wave can be converged now.

  The transmission / reception unit 14 included in the second ultrasonic flaw detector is connected to the transmission-side probe 18 and the reception-side probe 19, and current is applied from the transmission / reception unit 14 to the transmission-side probe 18. Then, the vibrator 22 vibrates and emits ultrasonic waves. When emitting ultrasonic waves, the lower surfaces of the wedges 20 and 21 are brought into contact with the outer peripheral surface of the pipe 11, and in this state, ultrasonic waves are emitted in the thickness direction (radial direction) of the pipe 11. Then, the reflected wave is detected by the transducer 23 of the receiving probe 19 and output to the transmitting / receiving unit 14.

  The arithmetic processing unit 15 processes the reflected wave signal received by the transmission / reception unit 14 and transmits the processed data to the storage unit 16 and the display unit 17. The storage unit 16 stores processing data, and the display unit 17 can output and display the processing data as an image. As the arithmetic processing unit 15, the storage unit 16, and the display unit 17, a personal computer can be used as in the first ultrasonic flaw detection apparatus.

FIG. 9 shows an example of a reflected signal displayed when an inspection is performed using the second ultrasonic flaw detector.
Here, as shown in FIG. 9 (A), the above-mentioned phased array flaw detection sensor 13 is surrounded from the position directly above the hole 24 with respect to the pipe 11 having a φ2 conical hole 24 formed on the inner peripheral surface. The ultrasonic waves were generated by disposing at a position shifted by 3 mm in the direction. The result is shown in FIG.

  In FIG. 9B, the range indicated by the arrow D corresponds to the thickness of the pipe. In a range D corresponding to this thickness, the signal intensity of the reflected wave is basically displayed low (color is light). However, in the portion surrounded by the dotted line E in the same figure, the signal intensity of the reflected wave is displayed high (the color is dark), and this corresponds to the conical hole 24. As described above, according to the second ultrasonic flaw detector, the presence or absence of a hole (thinned portion) can be confirmed by confirming the location where the reflected signal strength increases, and the signal strength thereof. Therefore, it is possible to grasp the size of the hole (thickness reduction).

  Further, the phased array flaw detection sensor according to the present embodiment can change the focal point of the ultrasonic convergent beam in the left-right direction, so that detection in a wide region is possible. As other probes, for example, a focus type vertical probe 130A capable of converging ultrasonic waves emitted from a plurality of transducers as shown in FIG. A split type vertical probe 130B having a transducer dedicated to transmission and a transducer dedicated to reception as shown in FIG. 10B, and a general-purpose probe having a transducer serving both as transmission and reception as shown in FIG. Although there is a child 130C, since the ultrasonic transmission direction cannot be changed in the left-right direction, the range that can be detected at a time is limited. On the other hand, the phased array flaw detection sensor of this embodiment can detect in a wide range and has an advantage of shortening the inspection time.

  Moreover, the phased array flaw detection sensor of the present embodiment can change the ultrasonic focused beam in the left-right direction, so that even if it is a conical hole that is difficult to detect with the general-purpose probe 130C shown in FIG. Detection is possible. That is, as in the general-purpose probe 130C shown in FIG. 10C, the type that emits ultrasonic waves only in the radial direction of the pipe (perpendicular to the outer peripheral surface) has a surface orthogonal to the ultrasonic transmission direction. Detectability such as a flat bottom hole is good, but it is difficult to receive a reflected wave with respect to a pyramidal hole, and the detectability tends to be poor. On the other hand, in the phased array flaw detection sensor of the present embodiment, the ultrasonic focused beam can be changed in the left-right direction, so the ultrasonic focused beam can be emitted in a direction orthogonal to the weight-shaped surface, The reflected wave can be received with high sensitivity. Thus, in the case of this embodiment, it is excellent also in detection accuracy.

Further, the present inventor conducted an experiment for examining each detectable range using the present embodiment and the probe shown in FIG. The result is shown in FIG.
In this experiment, a φ2 flat bottom hole, a φ5 flat bottom hole, a φ2 conical hole, and a φ5 conical hole are respectively formed on the inner peripheral surface of the pipe, and the probe is shifted in the pipe circumferential direction from directly above each hole. Detected and investigated how far the hole could be detected. Whether or not detection is possible is determined as being detectable until the signal intensity of the reflected wave is half the signal peak value when the ultrasonic wave is emitted at a position directly above the hole. The deviation distance from the hole shown on the vertical axis in FIG. 11 is the sum of the distances shifted from directly above the hole to both sides in the circumferential direction, and the deviation distance on one side is half of the value plotted in FIG. It becomes. As shown in FIG. 11, the sensor according to the present embodiment can detect up to the farthest position compared to other probes for any of the various holes.

  Although the inspection apparatus used in the present invention has been described above, the first ultrasonic flaw detector and the second ultrasonic flaw detector have different advantages and disadvantages. The first ultrasonic flaw detector can perform a long-range flaw detection in the pipe axis direction compared to the second ultrasonic flaw detector by sending a guide wave in the axial direction of the pipe. The accuracy of detecting the position and size of the scratch is poor. On the other hand, the second ultrasonic flaw detector is superior to the first ultrasonic flaw detector in the detection accuracy in the local range, but cannot perform long distance flaw detection in the pipe axis direction. Therefore, in the present invention, the respective disadvantages are complemented by the respective advantages, and an efficient and accurate inspection of small-diameter piping is realized.

  In the inspection method according to the present invention, first, piping is flawed using the first ultrasonic flaw detector. Thereby, when a defect (thinning part) exists in piping, the existing range is specified roughly. Next, in the range specified by the first ultrasonic flaw detector, accurate flaw detection is performed using the second ultrasonic flaw detector. For example, in the case of 4B piping, since the first ultrasonic flaw detector can specify that there is a defect in the range of 200 mm in the axial direction and 60 mm in the circumferential direction, flaw detection is performed using the second ultrasonic flaw detector within this range. Will do.

  As shown in FIG. 12, when the range F specified by the first ultrasonic flaw detector is long in the axial direction of the pipe and short in the circumferential direction, the phased array flaw detection sensor 13 of the second ultrasonic flaw detector is It arrange | positions so that the incident angle change direction G of an ultrasonic convergence beam may be orthogonal to the axial direction of piping, and it moves to a piping axial direction. Thereby, the number of times the phased array flaw detection sensor 13 is shifted in the circumferential direction can be reduced, which is efficient. Specifically, in the present embodiment, according to the experimental results shown in FIG. 11, it is possible to detect even a total displacement of 9.5 mm from right above the hole to both sides of the 2φ flat bottom hole and the conical hole. In order to be able to detect, it is made to shift in the circumferential direction at a pitch P of 4.7 mm, which is about a half of that.

  On the contrary, as shown in FIG. 13, when the range F specified by the first ultrasonic flaw detector is short in the axial direction of the pipe and long in the circumferential direction, the phased array flaw detection sensor 13 is placed in the circumferential direction of the pipe. On the other hand, it arrange | positions so that the incident angle change direction G of an ultrasonic focused beam may intersect orthogonally, and it moves to the piping circumferential direction. In this case, the number of times the phased array flaw detection sensor 13 is shifted in the axial direction can be reduced, which is efficient.

  Further, even if the range specified by the first ultrasonic flaw detector (the range specified for one defect) is long in the pipe axis direction and short in the circumferential direction in terms of performance, FIG. As shown, when a plurality of defects H are arranged close to each other in the circumferential direction, the entire specific range F in which they exist may become long in the circumferential direction. In this case, as shown in FIG. 13, it is efficient to move the phased array flaw detection sensor 13 in the pipe circumferential direction and shift it in the axial direction.

  In addition, as shown in FIG. 12, when the phased array flaw detection sensor 13 is moved in the pipe axis direction and shifted in the circumferential direction, the contact surfaces of the wedges 20 and 21 with respect to the outer peripheral surface of the pipe as shown in FIG. 20b and 21b may be formed in a concave curved surface in a direction parallel to the incident angle changing direction G of the ultrasonic focused beam. More preferably, the curvature of the contact surfaces 20b and 21b should be equal to the curvature of the pipe outer peripheral surface. Thereby, the phased array flaw detection sensor 13 can be stably brought into contact with the outer peripheral surface of the pipe, and the detection accuracy is improved.

  On the other hand, as shown in FIG. 13, when the phased array flaw detection sensor 13 is moved in the pipe circumferential direction and shifted in the axial direction, the contact surfaces of the wedges 20 and 21 with respect to the pipe outer circumference as shown in FIG. 20b and 21b are preferably formed in a concave curved surface in a direction orthogonal to the incident angle changing direction G of the ultrasonic focused beam. Also in this case, more preferably, the curvature of the contact surfaces 20b and 21b should be equal to the curvature of the pipe outer peripheral surface. Thereby, the phased array flaw detection sensor 13 can be stably brought into contact with the outer peripheral surface of the pipe, and the detection accuracy is improved.

  Also, by preparing both the wedges 20 and 21 shown in FIG. 15 and the wedges 20 and 21 shown in FIG. 16, the wedges 20 and 21 can be replaced according to a specific range by the first ultrasonic flaw detector. Both the case where the phased array flaw detection sensor 13 is moved mainly in the axial direction (in the case of FIG. 12) and the case where it is moved mainly in the circumferential direction (in the case of FIG. 13) can be dealt with.

  As described above, according to the present invention, the first ultrasonic flaw detection that roughly specifies the range in which a pipe defect exists using the long-range flaw detection function in the pipe axis direction by the first ultrasonic flaw detection apparatus. Since the second ultrasonic flaw detection process for accurately specifying the size and position of the defect is performed using the second ultrasonic flaw detector within the range specified by the first ultrasonic flaw detector. It is possible to check efficiently and accurately. As a result, for example, the inspection time can be significantly shortened as compared with the case where the inspection is performed using only the general-purpose probe as shown in FIG.

FIG. 17 shows an example of the time required for each of the inspection method according to the present invention and the case where the inspection is performed using only the general-purpose probe.
In this case, inspection work was performed on the 3B pipe and the 4B pipe (both have a pipe length of 5.5 m). When 3B piping was inspected by the inspection method according to the present invention, it took 110 minutes for the first ultrasonic inspection process, 79 minutes for the second ultrasonic inspection process, and a total inspection time of 189 minutes. On the other hand, when the 3B pipe was inspected using only the general-purpose probe, an inspection time of 1123 minutes was required. This is because the general-purpose probe cannot perform long-distance flaw detection in the pipe axis direction, and therefore the defect range cannot be roughly specified, and much inspection time is required. On the other hand, in the inspection method according to the present invention, since the defect range can be roughly specified in the first ultrasonic flaw detection process, the inspection time can be shortened. As a result, the inspection time uses only the general-purpose probe. It was about 5.9 times lower than the previous case. Similarly, when the 4B pipe is inspected, the inspection method according to the present invention is used, and the inspection time is about 6.8 times lower than when only the general-purpose probe is used. .

  Further, in the embodiment of the present invention, in order to accurately inspect a small-diameter pipe, the vibrator included in the second ultrasonic flaw detector is replaced with a vibrator that performs only ultrasonic transmission (transmission side probe). And the transducer (receiving probe 19) that only receives ultrasonic waves. In small-diameter piping, the distance from the position of the transducer to the reflection target, such as a defect, may be very short. In that case, the timing at which the reflected wave returns is early. There is a possibility that the reflected wave returns and the reflected wave cannot be received well. Therefore, as in the above-described embodiment, the transducer on the transmission side and the transducer on the reception side are separated from each other, so that even if the reflected wave returns at an early timing, the transducer on the reception side is good. It will be possible to receive.

  In the above-described embodiment, the ultrasonic transmission direction of the transmission side probe 18 and the ultrasonic reception direction of the reception side probe 19 are oblique to each other, thereby realizing a short focus of 3 mm in depth. Therefore, it is suitable for inspection when there is a defect in a shallow position.

  It should be noted that the present invention is not limited to the above-described embodiments, and can of course be implemented in various forms without departing from the gist of the present invention. The scope of the present invention is defined by the terms of the claims, and includes the equivalent meanings recited in the claims and all modifications within the scope.

DESCRIPTION OF SYMBOLS 1 1st ultrasonic flaw detector 7 vibrator 11 piping 12 2nd ultrasonic flaw detector 18 transmission side probe 19 reception side probe 20 wedge 20b contact surface 21 wedge 21b contact surface 22 transducer 23 vibration Child G Incident angle change direction of ultrasonic focused beam

Claims (6)

A small-diameter piping inspection device for inspecting small-diameter piping,
A range in which there are a plurality of transducers arranged in the circumferential direction on the outer peripheral surface of the pipe, and ultrasonic waves are emitted from the respective vibrators in the axial direction of the pipe, and the reflected waves are received to cause defects in the pipe. A first ultrasonic flaw detector for identifying
In the range specified by the first ultrasonic flaw detector, the ultrasonic transmission timing of each vibrator emitted from the outside of the pipe in the thickness direction is provided with a plurality of vibrators arranged in one or a plurality of rows. A small-diameter pipe inspection apparatus comprising: a second ultrasonic flaw detector that controls and converges ultrasonic waves to an arbitrary position and receives a reflected wave thereof to perform flaw detection on the pipe.   The small-bore pipe inspection according to claim 1, wherein the vibrator of the second ultrasonic flaw detector is divided into a vibrator that only transmits ultrasonic waves and a vibrator that only receives ultrasonic waves. apparatus.   The small aperture according to claim 2, wherein an ultrasonic wave transmission direction of the vibrator that performs only the ultrasonic wave transmission and an ultrasonic wave reception direction of the vibrator that performs only the ultrasonic wave reception are oblique to each other. Piping inspection device.   The contact surface with respect to the outer peripheral surface of the pipe of the second ultrasonic flaw detector is formed in a concave curved surface in a direction parallel to the incident angle changing direction of the ultrasonic convergent beam. The small-bore pipe inspection device according to any one of the above items.   The contact surface with respect to the outer peripheral surface of the pipe of the second ultrasonic flaw detector is formed in a concave curved surface in a direction orthogonal to the incident angle changing direction of the ultrasonic convergent beam. The small-diameter pipe inspection device according to claim 1. A small-diameter piping inspection method for inspecting small-diameter piping,
A plurality of vibrators are arranged on the outer peripheral surface of the pipe in the circumferential direction, ultrasonic waves are emitted from the respective vibrators in the axial direction of the pipe, the reflected waves are received, and a range in which there is a defect in the pipe is specified. 1 ultrasonic flaw detection process,
In the range specified in the first ultrasonic flaw detection process, the ultrasonic wave transmission timing emitted from the outside of the pipe in the thickness direction of a plurality of transducers arranged in one or a plurality of rows is controlled to A small-diameter pipe inspection method comprising: a second ultrasonic flaw detection process for converging a convergent beam at an arbitrary position and receiving a reflected wave to flaw the pipe.