JP4287321B2 - Ultrasonic sensor - Google Patents

Description

  The present invention relates to an ultrasonic flaw detection sensor, and more particularly, to a two-divided ultrasonic sensor suitable for water gap flaw detection.

  As a non-destructive inspection method for solids that allow both longitudinal and transverse waves to propagate, such as steel, an ultrasonic method (ultrasonic flaw detection method) has been generally used, but at this time, it is transmitted from the ultrasonic probe. If the ultrasonic beam spreads, the intensity of the diffracted wave may be reduced and the defect detection characteristics may be deteriorated.

  Therefore, as a method to dispel this concern, the ultrasonic beam emitted from the transmitting probe is focused and irradiated to the tip of the defect, and the diffracted wave detection area by the receiving probe is also focused and diffracted. There is a method for efficiently detecting waves in the prior art (see, for example, Patent Document 1 and Patent Document 2).

  This method is called a phased array (phased array) method, and further called an electronic scanning method or an electronic scanning method.For example, a probe in which a plurality of ultrasonic vibration elements made of piezoelectric elements are arranged in an array, Using a so-called array (array) probe, an electrical signal that triggers the generation of ultrasonic waves is delayed for a predetermined time for each element of this array probe, and synthesized with the ultrasonic waves generated from each element. It is an ultrasonic flaw detection method in which waves are formed.

  In addition, at this time, two array probes are fixedly arranged at regular intervals and used separately for transmission and reception, and the TOFD method (Time of Flight Diffraction) is used to overcome defects in the inspected body. An apparatus for ultrasonic flaw detection is also known as the prior art.

  In the case of this TOFD method, the angle (incident angle) of the ultrasonic wave incident on the inspection object from the transmitting probe is usually 45 to 55 degrees, and from the defect tip in the inspection object based on the ultrasonic wave. The angle at which the diffracted wave is received by the receiving probe (reception angle) is also usually set to 45 to 55 degrees (see also Patent Document 1).

  Here, when an attempt is made to detect diffracted waves efficiently, it is known that the incident angle of ultrasonic waves is preferably 45 degrees (see, for example, page 4-5 of Patent Document 2 and FIG. 2). .

  There is also a conventional example using the TOFD method and an electronic scanning method or an electronic scanning method (see, for example, page 3-6 of Patent Document 3 and FIGS. 1-12).

  Next, an example of the conventional ultrasonic flaw detection apparatus of this phased array system will be described with reference to FIG. 14. Here, first, the ultrasonic flaw detection apparatus shown in FIG. The apparatus main body 400 and the transmission / reception integrated type array sensor 14 are roughly divided, and a signal cable 500 is connected between them.

  First, as shown in FIGS. 15 and 16, the transmission / reception integrated sensor 14 (hereinafter abbreviated as the sensor 14) includes a plurality of ultrasonic vibration elements arranged in one direction, for example, the W direction, in the arrangement direction. Dividing into two, one is a transmission transducer array 15 and the other is a reception transducer array 19, with the flaw detection surface thereof facing the flaw detection surface that is the inspection target, and the inspection target material 21 It is designed to be mounted on the surface.

  Here, such a sensor in which a plurality of ultrasonic transducer elements arranged in one direction is divided into two in the arrangement direction, one as a transmission transducer array and the other as a reception transducer array, It is called an acoustic probe (sensor).

 The flaw detection surface at this time is a surface on which ultrasonic waves are generated from the transmission transducer array 15 and ultrasonic waves are received by the reception transducer array 19.

  Here, such a sensor in which a plurality of ultrasonic transducer elements arranged in one direction is divided into two in the arrangement direction, one as a transmission transducer array and the other as a reception transducer array, It is defined as an acoustic probe (sensor).

  Then, the ultrasonic wave 16 is transmitted from the vibrating elements A, B, C, and D of the transmission transducer array 15 constituting the transmission array sensor of the sensor 14 into the inspection target material 21 that is the inspection target, The oscillating elements O, P, and Q of the receiving transducer array 19 constituting the receiving array sensor are diffracted waves generated by diffracting the ultrasonic wave 16 at the lower end of the defect 22 in the inspection target material 21 based on the sound wave 16. , R and each vibration element serves to supply an electrical signal generated by receiving the diffracted wave to the ultrasonic flaw detector main body 400.

  As described above, the vibration elements A, B, C, and D of the transmission transducer array 15 are used for transmission of ultrasonic waves, and thus can be defined as transmission vibration elements. Since P, Q, and R are used for receiving ultrasonic waves, they can be defined as receiving vibration elements.

  The sensor 14 is placed on the surface of the inspection target material 21 so that the central portion (the central portion of the sensor 14) is positioned directly above the defect 22 on the surface of the inspection target material 21. . Here, in this figure, the center portion of the sensor 14 is between the vibration element D of the transmission transducer array 15 and the vibration element O of the reception transducer array 19.

  Next, the ultrasonic flaw detector main body 400 includes an input device 1 and a memory 2, an ultrasonic control device 3, an information processing device 4, an I / O (input / output interface) 5, a display device 6, a transmission super device, as shown in the figure. A sound wave oscillator control device 7, a reception signal processing device 8, a transmission side amplifier control device 9, a reception side amplifier control device 10, a transmission side amplifier 11, and a reception side amplifier 12 are provided.

  First, an input condition for determining an ultrasonic transmission / reception pattern is input to the memory 2 from the input device 1. Here, the input condition is a condition for determining an ultrasonic transmission / reception pattern necessary for detecting a defect with high sensitivity, and is input to the memory 2 and then transferred to the ultrasonic control device 3. The

  Therefore, in the ultrasonic control device 3, the ultrasonic wave 16 transmitted from each vibration element A, B, C, D of the transmission vibrator array 15 is focused on the focusing point 17 via the I / O 5, and the diffracted wave 18. Transmits an ultrasonic control signal necessary for efficient reception to each vibration element ○, P, Q, R of the reception transducer array 19 to the transmission ultrasonic transducer control device 7 and the reception signal processing device 8. .

  At this time, the transmission ultrasonic transducer control signal is amplified by the transmission-side amplifier 11 and supplied to each vibration element A, B, C, D of the transmission transducer array 15, and as a result, each vibration element A, B, Ultrasonic waves 16 each consisting of spherical waves are generated from C and D. At this time, since there is a time difference in the generation of each spherical wave, the ultrasonic waves 16 are focused at the position of the focusing point 17 inside the inspection target material 21. Is done.

  In the case of FIG. 1, in order to focus the ultrasonic wave 16 on the focusing point 17, the transmission signal must be input to the vibrating element A located farthest from the focusing point 17. The timing of the transmitted ultrasonic transducer control signal at that time is as shown in FIG. 17, and as a result, as shown in FIG. 18, ultrasonic waves are sequentially generated with a time difference.

  At this time, the delay times TtAmn, TtBmn, TtCmn,..., TtDmn for the vibration elements A, B, C, D necessary for focusing the ultrasonic wave 16 at the focusing point 17 are calculated by the ultrasonic control device 3. The

  Here, if there is a defect end portion at the position of the focusing point 17, in this case, the ultrasonic wave is diffracted at the defect end portion, and a diffracted wave 18 appears. Then, this diffracted wave 18 is incident on each of the vibration elements O, P, Q, and R of the receiving transducer array 19 with a time difference.

  In the case of FIG. 14, the diffracted wave 18 incident on the receiving-side vibrating element O closest to the converging point 17 is temporally earliest, and the diffracted wave 18 incident on the vibrating element R farthest from the converging point 17 temporally. The most late.

  Thus, assuming that the diffracted wave 18 is incident on each of the vibration elements O, P, Q, and R of the receiving transducer array 19, the intensity of the diffracted wave 18 incident on each of the vibration elements ◯, P, Q, and R is measured. An electric signal having a level corresponding to the signal is generated, amplified by the receiving-side amplifier 12, and then input to the received signal processing device 8.

  In the received signal processing device 8, the receiving focal point 17 (Fmn) by the vibrating elements O, P, Q, and R of the receiving vibrator array 19 and the vibrating elements O, P, Q, and R of the receiving vibrator array 19 are displayed. After controlling the reception timing Trimn for synthesizing each ultrasonic reception signal (electrical signal) according to the positional relationship (distance relationship), the ultrasonic reception signals are added to create one ultrasonic reception signal.

  The reception timing Trimn at this time is calculated by the ultrasonic control device 3, and the respective vibration elements O, P of the reception transducer array 19 are arranged at the reception focal point (same as the focal point 17 (Fmn)) determined by the input conditions. , Q and R are determined to be values necessary for focusing the reception focusing point.

  The ultrasonic reception signal created by the reception signal processing device 8 is transferred to the information processing device 4 and the memory 2 via the I / O 5. Then, after being processed by the information processing device 4 according to a predetermined display form, it is supplied to the display device 6 via the I / O 5 and displayed as flaw detection information.

  When the defect diffracted wave signal is displayed as flaw detection information on the display device 6 in this way, the presence of the defect can be recognized based on the presence of the defect diffracted wave signal, and the defect can be detected. The depth of the defect is determined based on the transmission time of the sound wave and the detection time of the diffracted wave, that is, the propagation time of the ultrasonic wave, thereby enabling defect sizing (defect size measurement).

  By the way, in the example of the ultrasonic flaw detector described above, as shown in FIG. 14, the sensor 14 is placed on the surface of the material 21 to be inspected. Separately, when performing ultrasonic flaw detection in water, for example, inspecting a reactor pressure vessel, the ultrasonic flaw detection is performed with the water layer interposed between the sensor and the surface of the inspection object. The so-called water gap method ultrasonic flaw detection is known as the prior art.

  When the sensor used in this water gap method ultrasonic flaw detection is applied to a two-part ultrasonic sensor, in order to suppress the ultrasonic wave from propagating directly from the transmission transducer array to the reception transducer array, A plate-like sound insulation member is provided between the transmission transducer array and the reception transducer array (see, for example, Patent Document 4).

  Thus, an example of a sensor provided with such a plate-like sound insulation member will be described with reference to FIG. 19. This sensor 14 has a flaw detection surface, that is, an entrance / exit of ultrasonic waves, passing through the transmitting transducer array 15 and the receiving transducer array 19. It is placed on the epoxy resin plate 101 that becomes the exit surface, and the position is fixed by the resin 102 and accommodated in the casing 100.

  The space between the casing 100 and the resin 102 is filled with a sound insulating material 103 such as a cork material. Here, a cork or the like is also provided between the transmission transducer array 15 and the reception transducer array 19. In addition, a plate-like sound insulation member 104 made of a material that hardly reflects ultrasonic waves is provided, thereby suppressing crosstalk of ultrasonic waves between the transmission transducer array 15 and the reception transducer array 19 and reducing noise and improving detection sensitivity. Can be planned.

Here, when this sensor 14 is applied to the water gap method, the plate-like sound insulation member 104 is protruded from the epoxy resin plate 101 serving as the flaw detection surface by a predetermined length L, thereby defining the water gap dimension, The function of a so-called surface reflection reducing plate that prevents the ultrasonic waves emitted from the transmission transducer array 15 from being reflected on the surface of the material to be inspected within the water gap and reaching the reception transducer array 19 as it is. Is to be obtained.
JP 2001-228128 A JP 2001-228126 A JP 2002-62281 A JP-A-6-331610

  The prior art described above is not considered in changing the water gap dimension when the two-divided ultrasonic sensor is applied to the water gap method, and there is a problem in the expected performance.

  That is, in the above prior art, when the two-part ultrasonic sensor is applied to the water gap method, the water gap dimension is the length of the plate-like sound insulation member protruding from the flaw detection surface of the sensor, for example, the prior art in FIG. In the case of the sensor according to (1), since it is determined by the length L, the water gap dimension cannot be changed, and the desired performance cannot be exhibited.

  Here, the water gap size change and the necessity for water gap ultrasonic inspection will be explained. First, the water gap ultrasonic inspection is applied to the inspection of the reactor pressure vessel as described above. Often done. Therefore, the following description will be made by taking the inspection of the reactor pressure vessel as an example.

  Here, FIG. 20 shows a case where the water gap method ultrasonic flaw detector is applied to flaw detection in the vicinity of the stub tube 31 of the CRD (control rod drive mechanism) housing at the bottom of the nuclear reactor and the nuclear pressure vessel 32. In this case, the sensor 14 is used while being held by the articulated manipulator 33. For this reason, the main body portion 34 of the inspection apparatus is connected to the pressure vessel by the distal end portion 35 of the stub tube 31 and the core support plate 36. It is fixedly held at the bottom of 32 furnaces.

  At this time, the signal cable of the sensor 14, the signal cable of the articulated manipulator 33, the power cable, and the high-pressure water hose are bundled together as a cable and a hose 37. Are extended to the operation floor and connected to each control device.

  Here, the manipulator base 38 is held by the main body 34 of the inspection apparatus via the vertical rotation mechanism 39, so that the manipulator base 38 can move in the vertical direction R1 and the rotation direction S1 with respect to the main body 34. Has been.

  On the other hand, the manipulator 33 includes three bending indirect portions 40 and two rotation indirect portions 41, and a hand 42 is provided at the tip thereof, thereby gripping and holding the grip portion 43 of the sensor 14.

  At this time, between the sensor 14 and the gripping portion 43, a compliance mechanism 44 that can be shifted over three axes of X, Y, and Z is installed, and the sensor 14 is connected to the CRD housing stap tube 31 and the nuclear pressure vessel. The posture can be changed smoothly following the curved surfaces such as 32 and their welds.

  Therefore, in this case, a gap remains between the flaw detection surface of the sensor 14 and the surface to be inspected, and it is inevitable that a water layer is interposed here, and inevitably water gap method ultrasonic flaw detection is performed. It must be picked.

  By the way, in the case of this water gap method ultrasonic flaw detection, it is desirable that the dimension of the water gap, that is, the thickness of the water layer is arbitrarily changed, for the following reason.

・ Improved defect detectability and discriminability In the case of a complex part such as a CRD stub tube, it is difficult to accurately evaluate and estimate the incident direction of the ultrasonic wave, It is difficult to accurately evaluate and estimate the tissue flow and physical properties that affect the bending of sound.

  For this reason, along with electronic scanning of ultrasonic waves, the ultrasonic sensor is tilted with respect to the surface of the metal (inspected object) on which ultrasonic waves are incident, or the distance from the metal surface is changed, that is, the size of the water gap is changed. Therefore, it is necessary to size the defect after finding the condition for focusing and irradiating the ultrasonic wave at the tip of the defect, and therefore, the water gap size needs to be changed from the viewpoint of improving the detectability and distinguishability of the defect. It is.

・ Difference between surface multiple reflection echo and defect echo Now, the distance from the metal surface to the tip of the defect, that is, the defect depth is Lm [m], and the distance from the ultrasonic sensor to the metal surface, that is, the water gap is Lw [ m], the ultrasonic propagation time Ttotal [s] is expressed by the following equation (1).

Ttotal = Tw + Tm
= 2Lw / Vw + 2Lm / Vm (1)
Ttotal: Defect tip echo is detected after ultrasonic wave is emitted from the sensor
Time until incident on [s]
Tw: Time for ultrasonic waves to propagate in water [s]
Tm: Time for ultrasonic wave to propagate through metal [s]
Lw: Water gap [m]
Lm: Defect depth [m]
Vw: Speed of sound in water [m / s]
Vm: Speed of sound in metal subject to inspection [m / s]
On the other hand, the propagation time Tr of the multiple anti-echo of ultrasonic waves occurring between the ultrasonic sensor and the metal surface is expressed by the following equation (2).

Tr = n · Tw (2)
n: positive integer Therefore, for example, flaw detection is performed at a defect depth Lm = 20 [mm], a water gap Lw = 5 [mm], and a sound velocity Vw = 1500 [m / s] in water, and in a metal. If the sound velocity Vm is 6000 [m / s], the propagation time Ttotal of the ultrasonic wave is 6.67 [μs].

  At this time, the propagation time Tr of the surface multiple reflection echo is 3.33 [μs] when n = 1, 6.67 [μs] when n = 2, 10.00 [μs] when n = 3,... In this case, even if a slight surface multiple reflection echo is generated, the propagation time Ttotal of the ultrasonic wave, which is a signal representing the defect, coincides with the propagation time Tr of the multiple anti-echo (Ttotal = Tr = 6. 67 [μs]), the defect signal will be overlooked.

  On the other hand, if only the water gap Lw is changed under the same conditions as described above, for example, when flaw detection is performed with the water gap Lw = 10 [mm], the ultrasonic wave propagation time Ttotal is 10.00 [μs], and n = 1. The propagation time Tr of the surface multiple reflection echo is 6.67 [μs]], 13.33 [μs] when n = 2, 20.00 [μs] when n = 3, and so on. The propagation time Ttotal of a certain ultrasonic wave and the propagation time Tr of the surface multiple reflection echo can be made different so that a defect signal can be recognized.

  Therefore, in this case, it is necessary to change the water gap Lw to prevent the defect signal from being overlooked. Therefore, it is necessary to change the size of the water gap from the viewpoint of separating the surface multiple reflection echo from the defect echo. It is.

  An object of the present invention is to provide a two-divided ultrasonic sensor that can be applied to water flaw detection so that desired performance can be exhibited.

At this time, the basic idea of the present invention is that in the ultrasonic sensor for water gap flaw detection provided with a plate-like sound insulation member between the transmission transducer row and the reception transducer row, the plate-like sound insulation member is connected to the transmission vibration. The point is that the element is held between the transmission transducer array and the reception transducer array while being movable in a direction perpendicular to the flaw detection surface of the slave array and the reception transducer array.

Accordingly, the object is to provide a water gap flaw detection ultrasonic sensor having a plate-like sound insulation member between a transmission transducer row and a reception transducer row, wherein the plate-like sound insulation member is the transmission transducer row and the reception transducer. It is composed of a plurality of strip members extending in a direction perpendicular to the flaw detection surface in a row and arranged in the width direction, and each of the plurality of strip members is independent of each other, and each tip is external to the flaw detection surface. This is achieved by being elastically held in the direction of exposure .

  Further, at this time, even if the plate-like sound insulating member is provided with a notch at the tip, the above-mentioned object is achieved.

  According to the present invention, the front end of the plate-like sound insulation member can be easily followed and brought into contact with a complicated shape such as a CRD stub tube or a shroud support. The two-part ultrasonic sensor can be applied to the water gap method and desired performance can be exhibited arbitrarily.

  Hereinafter, an ultrasonic sensor according to the present invention will be described in detail with reference to embodiments shown in the drawings.

  First, FIG. 1 shows an ultrasonic sensor 140 according to an embodiment of the present invention, and FIG. 2 shows details of the ultrasonic sensor 140 shown in FIG. 1 is a cross-sectional view as seen from the front of FIG. 1, and FIG.

  The ultrasonic sensor 140 includes a transmission transducer array 150 and a reception transducer array 190 to form a two-divided array sensor, and a surface between the transmission transducer array 150 and the reception transducer array 190. By providing a plate-like sound insulation member 154 that also functions as a reflection reducing plate, it can be applied to a sensor for water gap method flaw detection.

  Here, the transmission transducer array 150 corresponds to the transmission transducer array 15 in the conventional ultrasonic sensor 14 described with reference to FIG. 19, and the reception transducer array 190 is also the reception transducer array in the prior art of FIG. Therefore, detailed description thereof is omitted.

  On the other hand, the plate-like sound insulation member 154 similarly corresponds to the plate-like sound insulation member 104 in the prior art of FIG. 19, but in this embodiment, as in the case of the prior art of FIG. It is not fixed between the row 150 and the receiving transducer row 190 but is held movably.

  That is, the plate-like sound insulation member 154 is movable in a direction perpendicular to the flaw detection surfaces 1501 and 1901 of the transmission transducer array 150 and the reception transducer array 190, that is, in the direction indicated by the arrow A in these drawings. The transmission transducer array 150 and the reception transducer array 190 are held.

  For this reason, spacer members 200 and 201 are inserted between the transmission transducer array 150 and the reception transducer array 190, thereby forming a space between the transmission transducer array 150 and the reception transducer array 190. The plate-like sound insulation member 154 is accommodated therein and held so as to be movable.

  Here, one end portion of the plate-like sound insulating member 154, that is, the end portion 1541 on the opposite side to the end portion 1541 exposed to the outside from the flaw detection surfaces 1501 and 1901 of the transmitting transducer array 150 and the receiving transducer array 190 is provided. A T-shaped top 1542 is formed at the end.

  The case portion 210 is attached to the end surface of the transmitting transducer array 150 and the receiving transducer array 190 opposite to the flaw detection surfaces 1501 and 1901 in a form in which the top portion 1542 is accommodated therein. A spring 300 made of a coil spring is provided so as to push 1542.

  At this time, in the illustrated state, the spring 300 is contracted to a predetermined length from the original length, that is, the length in the free state, so that the top portion 1542 of the plate-like sound insulating member 154 is obtained. And the case portion 210.

  Thus, when the end portion 1541 of the plate-like sound insulation member 154 is pressed, the end portion 1541 of the plate-like sound insulation member 154 moves from the flaw detection surfaces 1501 and 1901 of the transmission transducer array 150 and the reception transducer array 190 to the inside. The reaction force at this time, that is, the force necessary to push in the plate-like sound insulation member 154 can be set to an arbitrary strength by giving the spring 300 a desired spring constant. Can be

  Next, the flaw detection operation by the ultrasonic sensor 140 will be described with reference to FIG. Here, FIG. 3 shows a state in which the ultrasonic sensor 140 is used to inspect the inspection target material 21, and the depth measurement and defect sizing of the defect 22 existing in the inspection target material 21 are performed by the water gap method. It is a thing.

  In this case, the ultrasonic sensor 140 grips and holds the grip portion 43 (FIG. 1) on the hand 42 of the articulated manipulator 33 described with reference to FIG. 20, for example, so that the vicinity of the desired surface of the inspection target material 21 is obtained. To be able to position. At this time, the compliance mechanism 44 (FIG. 20) is not used.

  The ultrasonic sensor 140 is positioned in the vicinity of the desired surface of the inspection target material 21 with the water gap dimension G, and the end 1541 of the plate-like sound insulating member 154 contacts the surface of the inspection target material 21. In this state, ultrasonic flaw detection is performed to obtain ultrasonic flaw detection by the water gap method.

  At this time, as described above, it is necessary to perform flaw detection by changing the water gap dimension G from the viewpoint of improving defect detectability and discriminability and from the viewpoint of separating the surface multiple reflection echo from the defect echo.

  Therefore, in this case, after positioning, the ultrasonic sensor 140 is further moved in the arrow S direction. At this time, in the ultrasonic sensor 140, the plate-like sound insulation member 154 is movable in the arrow A direction. In addition, the spring 300 is pressed with elasticity.

  For this reason, even if the ultrasonic sensor 140 is moved in the arrow S direction, the end 1541 of the plate-like sound insulation member 154 is not separated from the surface of the inspection target material 21, and can always be kept in contact. .

  However, this requires that the maximum value of the water gap dimension G is within the moving stroke of the plate-like sound insulation member 154, so that ultrasonic flaw detection is performed by the water gap method using the ultrasonic sensor 140. When performing, it is necessary to change the water gap dimension G within a range not exceeding the moving stroke of the plate-like sound insulating member 154.

  Here, the movement stroke of the plate-like sound insulation member 154 is a length that allows the plate-like sound insulation member 154 to move. This is an arbitrary design range of the ultrasonic sensor 140 within a desired range. Can be decided.

  Therefore, according to the ultrasonic sensor 140, even if the water gap size is changed by applying to the water gap method, the state where the end portion 1541 of the plate-like sound insulating member 154 is in contact with the surface of the inspection target material 21 is maintained. As a result, there is no possibility that the function of the plate-like sound insulation member 154 is impaired, and the performance obtained by applying the two-part ultrasonic sensor to the water gap method can be sufficiently exhibited.

  Next, another embodiment of the present invention will be described. First, FIG. 4 shows an embodiment in which the air cylinder 310 is used to move the plate-like sound insulating member 154. The air cylinder 310 is shown in the drawing. The plate-like sound insulation member 154 is inserted between the top 1542 and the case part 210.

  Therefore, when performing ultrasonic flaw detection by the water gap method, for example, when the water gap dimension is changed, if the air cylinder 310 is appropriately operated as necessary, the top portion 1542 of the plate-like sound insulation member 154 is pushed. The end 1541 can be kept in contact with the surface of the material 21 to be inspected regardless of the change in the water gap size.

  Therefore, the embodiment of FIG. 4 can also eliminate the possibility that the function of the plate-like sound insulation member 154 is impaired, and the performance obtained by applying the two-part ultrasonic sensor to the water gap method is sufficiently high. It can be demonstrated.

  Here, in FIG. 4, the movable portion of the air cylinder 310 is independent of the top portion 1542 of the plate-like sound insulation member 154. However, in the embodiment of the present invention, these are combined to move the air cylinder 310. The plate-like sound insulation member 154 may be integrated.

  By the way, in the description of the above embodiment, the planar shape of the end portion 1541 of the plate-like sound insulating member 154 has not been particularly mentioned. However, as shown in FIG. Is common.

  5A is a side view of the ultrasonic sensor 140, FIG. 5B is a front view, and FIG. 5C is a state where the ultrasonic sensor 140 is positioned on the surface of the material 21 to be inspected. In this case, there is no particular problem because the end 1541 can be brought into contact with the surface of the material 21 to be inspected even if it is linear.

  On the other hand, FIG. 6 shows an embodiment in which the end 1541 of the plate-like sound insulation member 154 has an arc shape and the planar shape is a semicircular shape. Here, FIG. 6A is a side view of the ultrasonic sensor 140. FIG. 4B is a front view, and FIG. 4C is a diagram showing a state where the surface is positioned on the surface of the inspection target material 21. FIG.

  In the case of FIG. 6, as shown in FIG. 6C, the end 1541 of the plate-like sound insulation member 154 is brought into contact with the surface of the inspection target material 21 along the arcuate direction, and the ultrasonic wave A preferred embodiment is shown when flaw detection is performed. At this time, since the end portion 1541 has an arc shape, even if the surface of the material 21 to be inspected has an arc shape, there is not much gap left. Can be contacted without.

  Next, FIG. 7 is also an embodiment of the present invention, FIG. 7 (a) is a cross-sectional view seen from the front, FIG. 7 (b) is also a side view, and the ultrasonic sensor according to this embodiment Reference numeral 140 denotes a plate-like sound insulation member 154 that is composed of a plurality of strip members 154A to 154H extending in the vertical direction and arranged in the width direction, and provided with springs 300A to 300H made of coil springs, respectively. .

  As a result, the plurality of strip members 154A to 154H are held so as to be independently movable, and the respective tips 1541A to 1541H are elastically held in the direction exposed to the outside from the flaw detection surface. Is.

  Therefore, in the case of the ultrasonic sensor 140 according to the embodiment of FIG. 7, the ultrasonic sensor 140 is positioned on the surface of the inspection target material 21 (not shown), and the tips 1541A to 1541H of the strip members 154A to 154H are brought into contact with the surface. At this time, the strip members 154A to 154H are pushed into different positions depending on the shape of the surface.

  Therefore, according to the embodiment shown in FIG. 7, even if the surface of the material 21 to be inspected has a considerably complicated curved surface, the tips 1541A to 1541H of the strip members 154A to 154H can all be brought into contact with each other individually. The performance obtained by applying the two-divided ultrasonic sensor to the water gap method can be exhibited sufficiently.

  Here, the details of the plate-like sound insulation member 154 in the above embodiment will be described. It is necessary to configure the material with a material that hardly reflects ultrasonic waves. For this reason, first, FIG. This is an embodiment in which the plate-like sound insulation member 154 itself is made of a sound absorbing material such as Teflon (registered trademark), cork, natural rubber, synthetic rubber, porous material (foamed resin material, porous ceramics).

  Next, in FIG. 8B, the surface of the main body 154A of a metal material such as aluminum is coated with Teflon (registered trademark), cork, natural rubber, synthetic rubber, porous material (foamed resin material, porous ceramics), etc. In this embodiment, the sound absorbing layer 154B is formed and the plate-like sound insulating member 154 is configured.

  By the way, the plate-like sound insulation member 154 is often used in contact with the surface of the inspection object material 21 as described with reference to FIG. 3, and in this case, if the ultrasonic sensor 140 further moves, the inspection object The end 1541 of the plate-like sound insulation member 154 may slide on the surface of the material 21.

  Therefore, in the embodiment of FIG. 9A, protrusions 1541A and 1541B such as metal and Teflon (registered trademark) are provided on the end 1541 of the plate-like sound insulation member 154, and smoothly slide on the surface of the inspection target material 21. It is what I did.

  Next, in the embodiment of FIGS. 9B and 9C, rollers 1541C and 1541D such as metal and Teflon (registered trademark) are provided on the end 1541 of the plate-like sound insulation member 154, and the surface of the material 21 to be inspected is provided. 9 (b) is a case where rollers 1541C and 1541D are provided on one surface of the plate-like sound insulation member 154, and FIG. 9 (c) This is a case where the rollers 1541C and 1541D are provided on both side surfaces of the plate-like sound insulation member 154.

  Next, FIGS. 10 and 11 show an ultrasonic sensor 140 according to still another embodiment of the present invention. In this case, a notch 1542 is formed at the end 1541 of the plate-like sound insulating member 154. FIG. Here, the embodiment of FIG. 10 is provided with a notch 1542 in the embodiment of FIG. 5, and the embodiment of FIG. 11 is provided with a notch 1542 in the embodiment of FIG. 6. .

  By the way, in the above embodiment, the function of the plate-like sound insulation member 154 provided in the ultrasonic sensor 140 is that the ultrasonic waves emitted from the transmission transducer array 15 are on the surface of the inspection target material 21 in the water gap. From this point of view, the embodiments shown in FIGS. 10 and 11 seem to be contradictory to prevent reflection and reaching the receiving transducer array 19 as they are.

  However, at this time, if the size of the notch 1542 is appropriately set and the intensity of the ultrasonic wave that reaches the receiving transducer array 19 from the transmitting transducer array 15 through the notch 1542 is controlled, the ultrasonic wave is not generated. Even if it is leaked, it can be made to have little influence on the detection of the reflected wave for the original ultrasonic flaw detection.

  In addition, when the notch 1542 is provided in this way and the ultrasonic wave is intentionally leaked in a state where the intensity is controlled, the accuracy of the depth sizing of the defect 22 can be further increased.

  Therefore, in the embodiments of FIGS. 10 and 11, the plate-like sound insulating member 154 is provided with a notch 1542. Hereinafter, ultrasonic flaw detection by the ultrasonic sensor 140 of FIGS. 10 and 11 will be described with reference to FIG. Will be described.

  Here, FIG. 12 shows an image of a monitor in ultrasonic flaw detection, a so-called echo image. FIG. 12A shows a case where the plate-like sound insulation member 154 is not provided. FIG. 5B shows a case where a plate-like sound insulation member 154 is provided to substantially block leakage of ultrasonic waves. FIG. 10C shows an end portion of the plate-like sound insulation member 154 as shown in FIGS. This is a case where a notch 1542 is formed in 1541.

  First, when the plate-like sound insulation member 154 shown in FIG. 12A is not provided, a strong echo reflected on the surface of the inspection target material 21 appears as “surface reflection”. Then, since this is superimposed on the reflected wave for the original ultrasonic flaw detection, it can be seen that the flaw detection result is hardly discernable.

  Next, when the plate-like sound insulation member 154 shown in FIG. 12B is provided and the leakage of the ultrasonic wave is almost blocked, the echo due to the surface reflection does not appear, so the echo due to the defect is clearly indicated as “tip” and “bottom”. Therefore, it can be seen that the plate-like sound insulating member 154 can provide a high surface reflection blocking function.

  Therefore, this time, in the case where the notch 1542 of FIG. 12C is formed, the echo due to the defect is clearly displayed as the “tip” and the “bottom surface” in this case as well. It can be seen that another echo is displayed as “surface”.

  The echo displayed as the “surface” is reflected by the surface of the inspection object material 21 and is detected by the ultrasonic wave detected through the notch 1542. Therefore, the surface of the inspection object material 21 is literally displayed. Therefore, the distance between the “surface” and the “tip” accurately corresponds to the depth of the defect detected at this time.

  Here, when compared with the case of FIG. 12 (b), the echoes due to the defects are clearly displayed here as the “tip” and “bottom”, but only by this, their depth It is not immediately known, and a predetermined calibration (calibration: calibration) is required separately.

  On the other hand, in the case of FIG. 12 (c), as described above, the depth of the defect is obtained immediately and accurately from the echo image. Therefore, according to the embodiment of FIGS. The accuracy of depth sizing can be further increased.

  Next, FIG. 13 shows still another embodiment of the present invention. This ultrasonic sensor 150 uses a plate-like sound insulation member 1540 made of a stretchable material such as rubber as the plate-like sound insulation member. For example, a tip made of a hard material such as metal or Teflon (registered trademark) is provided at the tip.

  First, the plate-like sound insulation member 1540 made of a stretchable material such as rubber (natural rubber and synthetic rubber) expands and contracts in the direction indicated by the arrow A in FIG. Even if the sensor 150 is moved, the tip of the sensor 150 can be prevented from moving away from the surface of the material 21 to be inspected.

  At this time, since the chip 1543 is provided, a smooth movement can be obtained when sliding on the surface of the inspection target material 21.

  Therefore, even the embodiment of FIG. 13 can sufficiently exhibit the performance obtained by applying the two-divided ultrasonic sensor to the water gap method.

1 is a perspective view of a first embodiment of an ultrasonic sensor according to the present invention. It is detailed explanatory drawing of the 1st Embodiment of this invention. It is explanatory drawing showing the use condition of the ultrasonic sensor by this invention. It is explanatory drawing of 2nd Embodiment of the ultrasonic sensor by this invention. It is explanatory drawing of 3rd Embodiment of the ultrasonic sensor by this invention. It is explanatory drawing of 4th Embodiment of the ultrasonic sensor by this invention. It is explanatory drawing of 5th Embodiment of the ultrasonic sensor by this invention. It is explanatory drawing of the plate-shaped sound insulation member in the ultrasonic sensor of this invention. It is explanatory drawing of the plate-shaped sound insulation member in the ultrasonic sensor of this invention. It is explanatory drawing of 6th Embodiment of the ultrasonic sensor by this invention. It is explanatory drawing of 7th Embodiment of the ultrasonic sensor by this invention. It is explanatory drawing of the flaw detection operation | movement by the ultrasonic sensor which concerns on the 6th and 7th embodiment of this invention. It is explanatory drawing of 8th Embodiment of the ultrasonic sensor by this invention. It is a block diagram which shows an example of the ultrasonic flaw detector by a prior art. It is explanatory drawing which shows an example of the ultrasonic sensor by a prior art. It is explanatory drawing of the ultrasonic flaw detection by a phased array system. It is a wave form diagram of an electric pulse in a phased array system. It is a wave form diagram of an ultrasonic pulse in a phased array system. It is explanatory drawing which shows another example of the ultrasonic sensor by a prior art. It is explanatory drawing at the time of applying an ultrasonic sensor to the ultrasonic survey in a nuclear reactor.

Explanation of symbols

140: Ultrasonic sensor 150: Transmitting transducer array 154: Plate-shaped sound insulation member (surface reflection reduction plate)
190: reception transducer array 200, 201: spacer member 210: case portion 300: spring 1501, 1901: flaw detection surface (flaw detection surface of transmission transducer array and reception transducer array)
1541: End portion (end portion of plate-like sound insulation member)
1542: Top (T-shaped top of plate-like sound insulation member)

Claims (1)

In the ultrasonic sensor for water gap flaw detection provided with a plate-like sound insulation member between the transmission transducer array and the reception transducer array,
The plate-like sound insulation member is composed of a plurality of strip members extending in a direction perpendicular to a flaw detection surface of the transmission transducer array and the reception transducer array and arranged in a width direction,
An ultrasonic sensor characterized in that each of the plurality of strip members is elastically held in a direction in which each tip is exposed to the outside from the flaw detection surface .

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