JP7777489B2 - Ultrasonic flaw detection equipment - Google Patents

Description

The present invention relates to ultrasonic flaw detection technology for evaluating the integrity of structures such as penstocks.

In recent years, the average age of structures such as penstocks used in power plants has exceeded 50 years, and aging equipment has become a major problem. If the penstock is damaged due to corrosion and wear inside the penstock's fixing base, it can have an impact on third parties and cause overflow electricity due to long-term power outages. To measure the thickness of the wall inside the penstock's fixing base, power generation is stopped, the water flowing inside the penstock is stopped, and then temporary scaffolding is set up on the penstock's fixing base and an inspection is carried out from inside the penstock.
However, since the work is done on a steep slope, it is extremely dangerous, and in reality, many damage incidents have occurred inside the fixed base.
Generally, periodic inspections of exposed penstocks are carried out every 3 to 12 years. The thickness of the penstock used for stress assessment is measured from the outside of the pipe along a representative measurement line, and the results are used to evaluate the entire penstock. Therefore, there is no method for measuring the thickness inside the fixed base from the outside, and it has not been measured, raising concerns about defects. Therefore, there is a need for a device that can easily detect flaws inside penstocks, even when the penstock is filled with water.

As a technique for detecting flaws using ultrasonic waves, for example, a method of performing ultrasonic flaw detection using the diffraction phenomenon of SV waves (Shear Vertical Wave) is known (see Patent Document 1). In the angle beam method using SV waves, an ultrasonic beam is incident at an angle to the surface to be inspected and propagates into the interior of the structure to be inspected, and damage areas such as defects and corrosion inside the structure are inferred from the time and intensity of the resulting reflected echo. This method uses an angle beam probe, and longitudinal ultrasonic waves generated by the transducer are refracted at the surface to be inspected and are totally reflected at an angle greater than the critical angle and converted into ultrasonic shear waves. Only the converted ultrasonic shear waves propagate inside the structure.
In the ultrasonic flaw detection method disclosed in Patent Document 1, a probe with a refraction angle set within the range of 78 to 88° is placed on the flaw detection surface, ultrasonic waves are transmitted with the tip of the probe aligned with the position of the start of the boundary between the flaw detection surface and a thick section extending above the flaw detection surface, and a received signal including a reflected echo from a reflection source located above the flaw detection surface is obtained using diffracted waves that propagate while spreading within the thick section. The method also discloses preferred ranges for the opening angle of the sound axes of the transmitting probe and the receiving probe and the angle of the roof angle.

However, when inspecting the inside of a penstock, a probe is placed on the surface of the iron pipe, but the ultrasonic flaw detection inspection method of Patent Document 1 has the problem that it is difficult to ensure a constant gap between the probe and the iron pipe in accordance with the curvature of the iron pipe surface.
Furthermore, even if a certain gap could be secured between the probe and the iron pipe to match the curvature of the iron pipe surface, there was a problem in that the structure required replacing the wedge to change the ultrasonic refraction angle toward the material being inspected, making the operation complicated.

JP 2010-151501 A

In light of this situation, the present invention aims to provide an ultrasonic flaw detector that can easily and accurately determine the damage condition inside a fixed base from the outside using ultrasonic waves (SV waves) that propagate along the surface of a pipe structure such as a penstock.

In order to solve the above problems, the ultrasonic flaw detection device of the present invention is an apparatus for inspecting defects in tubular structures with shear waves and SV waves using two angle beam probes, and includes a transmitting unit consisting of an ultrasonic transmitting probe and an angle beam wedge, a receiving unit consisting of an ultrasonic receiving probe and an angle beam wedge, a transmitting probe holder to which the transmitting unit is attached and which has a mechanism for ensuring a gap between the surface of the tubular structure and the transmitting unit, a receiving probe holder to which the receiving unit is attached and which has a mechanism for ensuring a gap between the surface of the tubular structure and the receiving unit, a transmitting frame that rotatably supports the transmitting probe holder by an axial member, a receiving frame that rotatably supports the receiving probe holder by an axial member, and a hinge mechanism that connects the transmitting frame and the receiving frame. The transmitting probe holder and the receiving probe holder, which have mechanisms for ensuring a gap with the surface of the tubular structure, ensure a constant gap between the probe and the tubular structure, such as a penstock, so that the probe can conform to the surface of the tubular structure. Specifically, even when gel is used as a contact medium, the gel can be prevented from being scraped off by operating the probe. Also, the transmitting frame and receiving frame, which rotatably support the transmitting and receiving probe holders by shaft members, and the hinge mechanism that connects them, stabilize the positions of the transmitting probe and receiving probe arranged in the circumferential direction of the tubular structure, thereby improving the sensitivity of ultrasonic flaw detection along the axial direction of the tubular structure.

The constant gap ensured between the probe and the tubular structure is preferably 0.3 to 0.7 mm, and more preferably 0.5 mm.
The angle of the two beam probes is preferably 82 to 88°, more preferably 84 to 86°, and even more preferably 85°, and the frequency is preferably 0.05 to 15 MHz, more preferably 0.1 to 2 MHz, and even more preferably 0.5 MHz.
The reason why the present invention is an invention for a device using two oblique angle probes is that, while the present invention uses ultrasonic waves with low frequencies and long wavelengths, in the case of a device using one probe, the ultrasonic waves emitted from the probe remain inside the probe, making it difficult to detect flaws in the area in front of the probe.

In the ultrasonic flaw detection device of the present invention, the mechanism for ensuring a gap with the surface of the tubular structure preferably consists of multiple ball rollers.

In the ultrasonic flaw detection device of the present invention, the transmitting frame is preferably connected to the wheel axle via a connecting plate, and magnetic wheels are provided on both ends of the wheel axle. By attaching the magnetic wheels to the periphery of the penstock, inspection operability around the penstock can be improved.

In the ultrasonic flaw detection device of the present invention, the angle beam wedge may be filled with a liquid, and the liquid may be replaceable. By filling the angle beam wedge with a liquid of a different density, angle beam flaw detection can be performed at any angle without changing the shape of the wedge (without replacing the wedge).

In the ultrasonic flaw detection device of the present invention, the ultrasonic transmitting probe and the ultrasonic receiving probe are preferably provided with vibrators that can withstand an applied voltage of 800 V or more, more preferably with vibrators that can withstand a high voltage of 1000 V or more, and even more preferably with vibrators that can withstand a high voltage of 1500 V or more. By using vibrators that can withstand high voltage, it is possible to transmit high-power ultrasonic waves, and the flaw detection distance can be extended.

In the ultrasonic flaw detection device of the present invention, the ultrasonic transmitting probe and the ultrasonic receiving probe are provided with vibrators that can withstand a high applied voltage of 800 volts or more, and the angle wedge preferably has an incident angle of 82 to 88° for the shear SV waves incident from the wedge onto the tubular structure. The oblique angle of the angle wedge and the density inside the wedge are adjusted so that the incident angle of the shear SV waves incident from the wedge onto the tubular structure is 82 to 88°. If the incident angle of the shear SV waves incident from the wedge onto the tubular structure is 82 to 88°, it is possible to capture reflected echoes even if there is a distance between the measurement location and the defect location.

The ultrasonic flaw detection device of the present invention has the advantage of being able to ensure a constant gap between the probe and the iron pipe in accordance with the curvature of the iron pipe surface, making it possible to easily and accurately grasp the damage condition inside the fixed base from the outside. Furthermore, by using a wedge filled with liquid, the ultrasonic refraction angle can be changed without replacing the wedge, thereby improving convenience.

1 is a front view of an ultrasonic flaw detector according to a first embodiment of the present invention; 1 is a plan view of an ultrasonic flaw detector according to a first embodiment of the present invention; 1 is a bottom view of the ultrasonic flaw detector of Example 1. Image of ultrasonic flaw detection equipment in use 1 is an explanatory diagram of an ultrasonic probe according to a second embodiment of the present invention; Simulation results for various liquids inside the wedge Illustration of penstock soundness inspection An explanatory diagram of a conventional ultrasonic flaw detector Illustration of transmission and reception of ultrasonic flaw detector Graph showing the sensitivity of the probe in the ultrasonic flaw detector of Example 1 Ultrasonic flaw detection flow chart of Example 1

An example of an embodiment of the present invention will be described in detail below, with reference to the drawings. Note that the scope of the present invention is not limited to the following examples and illustrated examples, and many modifications and variations are possible.

Figure 1 shows a front view of the ultrasonic flaw detector of Example 1. As shown in Figure 1, the ultrasonic flaw detector 1 is composed of a detection unit (2a, 2b) and a probe holder 3, with the detection unit (2a, 2b) attached and fixed to the probe holder 3. The detection unit 2a consists of a transmitting probe 4a and an angle beam wedge 5a, and the detection unit 2b consists of a receiving probe 4b and an angle beam wedge 5b. The angle beam wedges (5a, 5b) are made of high-density polystyrene, which has little material variation and is relatively easy to process.

Fig. 2 shows a plan view of the ultrasonic flaw detection device of Example 1. Fig. 3 shows a bottom view of the ultrasonic flaw detection device of Example 1.
The transmitting probe 4a shown in Figures 1 to 3 is an ultrasonic probe, and as shown in Figure 3, it is provided with a high-voltage 1-3 composite vibrator 7a that can withstand a high voltage of 1000 V. A probe cable 9a is connected to the transmitting probe 4a via a connector 90a. The transmitting probe 4a is attached to an angle wedge 5a using fasteners (6a to 6d), and the detecting unit 2a is attached and fixed to a holder main body 31a as shown in Figures 1 to 3. A gap is provided between the holder main body 31a and the frame body 32a, and the holder main body 31a and the frame body 32a are rotatably fixed by shaft members (63a, 63b).
The wheels 33 are provided with wheels (33b, 33c) at both longitudinal ends of the wheel axle 33a. As shown in FIG. 2, the frame 32a and the wheels 33 are connected via connecting plates (35a, 35b). Specifically, the frame 32a and the connecting plate 35a are rotatably fixed by a fastener 61a, and the frame 32a and the connecting plate 35b are rotatably fixed by a fastener 61b. The wheels 33 and the connecting plate 35a are rotatably fixed by a fastener 62a, and the wheels 33 and the connecting plate 35b are rotatably fixed by a fastener 62b.

The receiving probe 4b shown in Figures 1 to 3 is an ultrasonic probe, and as shown in Figure 3, it is provided with a high-voltage 1-3 composite vibrator 7b. A probe cable 9b is connected to the receiving probe 4b via a connector 90b. The receiving probe 4b is attached to an angle wedge 5b using fasteners (6e to 6h), and the detecting unit 2b is attached and fixed to a holder main body 31b as shown in Figures 1 to 3. A gap is provided between the holder main body 31b and the frame body 32b, and the holder main body 31b and the frame body 32b are rotatably fixed by shaft members (63c, 63d).
The wheels 34 are provided with wheels (34b, 34c) at both longitudinal ends of the wheel axle 34a. As shown in FIG. 2, the frame 32b and the wheels 34 are connected via connecting plates (35c, 35d). Specifically, the frame 32b and the connecting plate 35c are rotatably fixed by a fastener 61c, and the frame 32b and the connecting plate 35d are rotatably fixed by a fastener 61d. The wheels 34 and the connecting plate 35c are rotatably fixed by a fastener 62c, and the wheels 34 and the connecting plate 35d are rotatably fixed by a fastener 62d.

As shown in Fig. 3, the frame body 32a and the frame body 32b are rotatably connected by a hinge portion 60. Furthermore, as shown in Fig. 2, the frame body 32a and the frame body 32b are also connected by connecting plates (36a, 36b). Specifically, the frame body 32a and the connecting plate 36a are rotatably fixed by a fastener 61e, and the frame body 32a and the connecting plate 36b are rotatably fixed by a fastener 61g. Furthermore, the frame body 32b and the connecting plate 36a are rotatably fixed by a fastener 61f, and the frame body 32b and the connecting plate 36b are rotatably fixed by a fastener 61h.
As shown in Figure 1, some of the connecting plates have oval through-holes. Specifically, connecting plate 35b has through-hole 11a, connecting plate 35d has through-hole 11b, and connecting plate 36b has through-hole 11c. By providing oval through-holes in the connecting portions, not only can the fixing points rotate, but the fixing positions of the fasteners can also move within the oval range, allowing them to move in accordance with the shape of the iron pipe. Although not shown, the connecting plates (35a, 35c, 36a) also have a similar mechanism.
In this embodiment, hexagon socket head bolts are used as the fasteners (61a to 61h) and hexagonal cap nuts are used as the fasteners (62a to 62d), but the present invention is not limited to these components and a wide range of known fasteners can be used.

In this way, not only are the frame bodies (32a, 32b) and the wheel parts (33, 34) movable, but the frame bodies (32a, 32b) and the holder main body (31a, 31b) are also movable, and further, the frame bodies 32a and 32b are also movable. This results in a structure in which the detection parts (2a, 2b) are each independently movable, and the angle of the probe in the circumferential direction can be changed to match the curvature of the iron pipe 12 to be inspected.
3, large ball rollers (8a to 8d) with plunger functions (not shown) are provided on the back surface of the holder body 31a, and similar ball rollers (8e to 8h) are provided on the back surface of the holder body 31b. By providing the ball rollers (8a to 8h), the heights of the transmitting probe 4a and the receiving probe 4b can be adjusted, and an appropriate gap between them and the iron pipe 12 can be adjusted.

Figure 7 is an explanatory diagram of a penstock soundness inspection. As shown in Figure 7, damage events such as damaged area 15 often occur inside the iron pipe 12 at the location where the fixing base 14 is installed. Therefore, in an inspection of the soundness of a penstock using the ultrasonic flaw detection device 1 of Example 1, the damage status inside the fixing base 14 of the iron pipe 12 is inspected from the outside using ultrasonic waves 13 (SV waves) that propagate along the surface of the penstock. Specifically, in the ultrasonic flaw detection device 1, ultrasonic waves 13a are emitted from the detection unit 2a, and the reflected echo 13b is detected by the detection unit 2b.

FIG. 4 is an image diagram of an ultrasonic flaw detector in use, where (1) shows the ultrasonic flaw detector of the embodiment, and (2) shows the ultrasonic flaw detector of the prior art.
8A and 8B are external views of an ultrasonic flaw detector according to the prior art, with (1) being a front view and (2) being a plan view. As shown in Fig. 8A or 8B, the ultrasonic flaw detector 100 according to the prior art has the same detection units (2a, 2b), wheel units (33, 34), connecting plates (35a, 35b), and fasteners (61a-61d, 62a-62d) as the ultrasonic flaw detector 1 according to the first embodiment. However, unlike the ultrasonic flaw detector 1 according to the first embodiment, the ultrasonic flaw detector 100 according to the prior art has a structure in which the holder body 310 of the probe holder 300 is immovable.
4(2), in the case of the ultrasonic flaw detector 100 of the prior art, it is not possible to maintain a constant gap between the detection units (2a, 2b) and the surface of the iron pipe 12 in accordance with changes in the curvature of the iron pipe 12. In contrast, in the ultrasonic flaw detector 1 of Example 1, the frame bodies (32a, 32b), holder bodies (31a, 31b), and ball rollers (8a to 8h) are movable, so it is possible to maintain a constant gap between the detection units (2a, 2b) and the surface of the iron pipe 12 in accordance with changes in the curvature of the iron pipe 12.

As mentioned above, the transmitting probe 4a and the receiving probe 4b use 1-3 composite vibrators (7a, 7b) with a high withstand voltage of 1.5 kV. These 1-3 composite vibrators (7a, 7b) use piezoelectric elements with a resonant frequency of 0.5 MHz. Conventionally, the withstand voltage of 1-3 composite piezoelectric elements is about 0.5 kV, and ceramic piezoelectric elements have been used for high withstand voltages. Piezoelectric elements are used below the polarization voltage, and since they lose their polarity when the polarization voltage is exceeded, ceramic piezoelectric elements with high polarization voltages have been used.
In the ultrasonic flaw detection device of the present invention, the adhesion of the vibrator electrodes is strengthened (specifically, by extending the drying time and using a high-strength adhesive), which makes it possible to adopt 1-3 composite vibrators (7a, 7b) with a high withstand voltage of 1.5 kV.

The other ends of the probe cables (9a, 9b) connected to the transmitting probe 4a and receiving probe 4b are connected to an ultrasonic pulser/receiver (not shown). The ultrasonic pulser/receiver is also designed to have a high-voltage resistance structure. For example, a high-speed, high-voltage, isolated DC-DC converter is used to obtain high voltage, and the applied voltage can be adjusted continuously from 0V to 1000V. Each capacitor has a high voltage resistance (1500V).

The transmitting probe 4a and receiving probe 4b use 1-3 composite vibrators (7a, 7b) with a high voltage resistance of 1.5 kV, and the angle wedges (5a, 5b) are adjusted so that the angle of incidence of the shear SV waves incident on the pipe structure from the wedge is 82 to 88 degrees. The angle of the angle wedge and the density inside the wedge are adjusted so that the angle of incidence of the shear SV waves incident on the pipe structure (iron pipe 12) from the ultrasonic waves emitted from the vibrator 7a via the angle wedge 5a is 82 to 88 degrees. This makes it possible to extend the detection distance from the measurement point to the defect location and capture reflected echoes from the defect.

FIG. 9 explains the ultrasonic transmission and reception paths for an ultrasonic flaw detection device that uses two oblique angle probes to inspect defects in pipe structures with shear waves and SV waves, in which the crossing angle between the sound axes of the ultrasonic transmitting probe and the ultrasonic receiving probe is fixed, and in which the crossing angle between the sound axes of the ultrasonic flaw detection device of the present invention is variable depending on the curvature of the iron pipe 12.
9(1) shows a case where flaws are detected on a flat surface, where the detecting units 2a and 2b are parallel and the crossing angle of the sound axes is fixed, and shows a shear SV wave 13a emitted from the detecting unit 2a being reflected by a damaged area 15 and entering the detecting unit 2b as a shear SV wave (reflected echo) 13b. In fact, the reflected echo 13b returns to the detecting unit 2b while spreading out as ripples.
Figure 9(2) shows the case where the same flaw detector as in Figure 9(1) (detecting units 2a and 2b are parallel and the crossing angle of the sound axes is fixed) is used to detect flaws on the surface of a curved iron pipe 12. In this case, the route of the reflected echo 13b changes, and the signal strength detected by detecting unit 2b decreases.
Figure 9(3) shows a case where flaws are detected on the surface of a curved iron pipe 12 using the ultrasonic flaw detector of Example 1 (where the crossing angle of the sound axes of the detectors 2a and 2b is variable depending on the curvature of the iron pipe 12). Unlike the case of Figure 9(2), signals can be detected while the signal strength detected by the detector 2b is maintained at the same level as in Figure 9(1).

Figure 10 is a graph showing the sensitivity of the probes in an ultrasonic flaw detector, with (1) showing the sensitivity of the comparative probe (0.8 MHz) and (2) showing the sensitivity of the probe of the example (0.5 MHz). Both show waveforms obtained when detecting flaws in an actual penstock, where a rivet 250 mm away was detected. As shown in Figure 10 (1), the sensitivity of the 0.8 MHz probe of the comparative example was 80.2 dB, while the sensitivity of the 0.5 MHz probe of the example was 62.8 dB, indicating that the 0.5 MHz probe is 17.4 dB (approximately 7.4 times) more sensitive.

Conventionally, flaw detection tests are performed with specific frequency filters set, and the optimal filter conditions are searched again after data collection is complete to find the optimal conditions. Figure 11 shows a flowchart of ultrasonic flaw detection in Example 1. As shown in Figure 11, first, the receiver receives a waveform (step S01). When transmitting and receiving an ultrasonic waveform, for example, if 500 signals are transmitted and received per second, this results in 50 signals per 0.1 second, and therefore signals are averaged and processed. For example, if the result of receiving for a fixed period of 0.1 seconds (step S02) contains a lot of noise and requires averaging of the received waveform data (step S03), averaging processing is performed (step S04). The averaging processing is performed because the flaw detection in this example may be performed at a sensitivity higher than the range used in general nondestructive testing, and improves the signal-to-noise ratio by averaging out random noise (external and internal electronic noise).

If filtering is required for the signal waveform data after averaging or for signal waveform data that does not require averaging (step S05), high-bandwidth signals are blocked (low-pass filter) (step S06), and low-bandwidth signals are further blocked (high-pass filter) (step S07). That is, window processing is performed to narrow the signal bandwidth and identify the reflected echo signal. Steps S06 and S07 may be performed in reverse order, or simultaneously. If filtering is required, filtered signal waveform data is acquired; if filtering is not required, the signal waveform data is acquired as is (step S08). Filtering refers to the fact that when ultrasonic waves propagate through a material, defect reflected echoes tend to be affected by the beam path length and the interior of the material, resulting in a frequency lower than the transmitted frequency. A wideband bandpass filter may be required to improve the identification of signal echoes. The ultrasonic flaw detection device of this embodiment is capable of performing wideband filtering in real time.
If it is necessary to acquire the next waveform data, the receiver receives the waveform again (step S01). On the other hand, if it is not necessary to acquire the next waveform data, the ultrasonic flaw detection ends (step S09).

5A and 5B are explanatory diagrams of the probe of Example 2, in which Fig. 5A is an image diagram from the right side and Fig. 5B is a plan image diagram from the right side of the transmitting detector 200. The receiving detector is not shown here, but the arrangement of each component is the same as that of the transmitting detector 200.
As shown in Figure 5 (1) or (2), the liquid wedge 500 is an angle beam wedge, and is made by filling a liquid 51 inside an acrylic resin case 50. The transmitting probe 4 is an ultrasonic probe, and is provided with a high-pressure-resistant 1-3 composite vibrator 7, which is attached and fixed to the liquid wedge 500 using fasteners 6. A probe cable 9 is also connected to the transmitting probe 4 via a connector 90. Because the case 50 of the liquid wedge 500 is filled with the liquid 51, angle beam testing is possible at any angle without replacing the wedge. The liquid 51 filled inside the case 50 can be water, alcohol, ethanol, or the like.

Figure 6 shows the simulation results (differences in refraction angle in steel) when various liquids are used inside the wedge, with (1) water, (2) alcohol, and (3) ethanol used as the liquid. Two ultrasonic probes, one for transmitting and one for receiving, were used in the simulation. The incident angle was fixed at 20.5° as a setting condition.
As shown in Figure 6(1), when the inside of the case 50 was filled with water, the refraction angle of the shear SV waves in the steel was 48.3°. As shown in Figure 6(2), when the inside of the case 50 was filled with alcohol, the refraction angle of the shear SV waves was 69.0°. Furthermore, as shown in Figure 6(3), when the inside of the case 50 was filled with ethanol, the refraction angle of the shear SV waves was 87.2°. Therefore, it can be seen that the refraction angle of the shear SV waves is approximately 45° when water is used, approximately 70° when alcohol is used, and that when ethanol is used, the waves propagate near the surface of the penstock.

By using the liquid wedge 500, shear SV waves are no longer generated in the liquid 51 inside the wedge, eliminating the unwanted echoes that occur due to mode conversion of the ultrasonic waves generated inside the wedge, resulting in a clearer received waveform during flaw detection. Furthermore, by changing the internal liquid to one with a different sound speed, the ultrasonic refraction angle (constant incident angle) on the material being inspected can be changed without having to replace the wedge, making it possible to use a probe holder with the same structure, including the wedge.

This invention is useful for technology to inspect the integrity of penstocks, spillway pipes, etc.

1,100 Ultrasonic flaw detection device 2a, 2b, 200 Detection unit 3,300 Probe holder 4, 4a Transmitting probe 4b Receiving probe 5a, 5b Beam wedges 6, 6a to 6h, 61a to 61h, 62a to 62d Fasteners 7, 7a, 7b 1-3 composite vibrator 8a to 8h Ball rollers 9, 9a, 9b Probe cable 11a to 11c Through hole 12 Iron pipe 13, 13a Ultrasonic waves (shear waves, SV waves)
13b Reflected echo 14 Fixing base 15 Damaged part 31a, 31b, 310 Holder body 32a, 32b Frame body 33, 34 Wheel part 33a, 34a Wheel axle 33b, 33c, 34b, 34c Wheel 35a to 35d, 36a, 36b Connecting plate 50 Case 51 Liquid 60 Hinge part 63a to 63d Shaft member 90, 90a, 90b Connector 500 Liquid wedge

Claims (5)

In an apparatus for inspecting defects in a tubular structure using a shear wave and a SV wave with a two-angle probe,
a transmitting unit consisting of an ultrasonic transmitting probe and an angle wedge;
a receiving section consisting of an ultrasonic receiving probe and an angle wedge;
a transmitting probe holder for attaching and fixing the transmitting unit and having a mechanism for ensuring a gap between the surface of the tubular structure and the transmitting unit ;
a receiving probe holder for attaching and fixing the receiving unit and having a mechanism for ensuring a gap between the surface of the tubular structure and the receiving unit ;
a transmitting frame that rotatably supports the transmitting probe holder by a shaft member;
a receiving frame that rotatably supports the receiving probe holder by a shaft member;
a hinge mechanism connecting the transmitting frame and the receiving frame;
Equipped with
An ultrasonic flaw detection device characterized in that the mechanism for ensuring the gap is made up of a plurality of ball rollers . In an apparatus for inspecting defects in a tubular structure using a shear wave and a SV wave with a two-angle probe,
a transmitting unit consisting of an ultrasonic transmitting probe and an angle wedge;
a receiving section consisting of an ultrasonic receiving probe and an angle wedge;
a transmitting probe holder having a mechanism for attaching and fixing the transmitting unit and ensuring a gap between the surface of the tubular structure and the transmitting unit;
a receiving probe holder having a mechanism for attaching and fixing the receiving unit and ensuring a gap between the surface of the tubular structure and the receiving unit;
a transmitting frame that rotatably supports the transmitting probe holder by a shaft member;
a receiving frame that rotatably supports the receiving probe holder by a shaft member;
a hinge mechanism connecting the transmitting frame and the receiving frame;
Equipped with
The transmitting frame is connected to the wheel shaft via a connecting plate,
An ultrasonic flaw detection device characterized in that magnetic wheels are provided on both ends of the wheel shaft. 3. The ultrasonic flaw detection device according to claim 1 , wherein the angle wedge is filled with a liquid, and the liquid is replaceable. 3. The ultrasonic flaw detection device according to claim 1, wherein the ultrasonic transmitting probe and the ultrasonic receiving probe are provided with vibrators that can withstand a high applied voltage of 800 volts or more. The ultrasonic wave transmitting probe and the ultrasonic wave receiving probe are provided with vibrators that can withstand a high voltage of 800 volts or more when applied ;
3. The ultrasonic flaw detection device according to claim 1 , wherein the angle of incidence of the shear SV wave incident on the tubular structure from the oblique angle wedge is 82 to 88 degrees.