JPS6355667B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an oblique transmission method comprising a transmitting probe that projects ultrasonic waves onto a subject and a receiving probe that receives the ultrasonic waves that pass through the subject. The present invention relates to an ultrasonic flaw detection device for use in ultrasonic flaw detection, and an oblique transmission flaw detection method using the device.

In the above-mentioned flaw detection apparatus, when performing flaw detection on a pipe, for example, conventionally, as shown in FIG.
Then, set the projection point A and transmission point B of the ultrasonic wave to the pipe 1, and then set the flat oscillators of both probes 6 and 7 based on the line connecting the center Pa of the pipe 1 and both points A and B. The projection angle θ and transmission angle θ' of the ultrasonic waves from near the center of the transducer 26 and 26 are adjusted, but if the projection angle θ of the flat transducer 26 on the transmitting side deviates even slightly, the transmitted ultrasonic wave As the projection point A with respect to the object 1 shifts, the flaw detection depth l changes accordingly, and the receiving side transducer 2
If the transmission angle θ' of No. 6 deviates, the reception efficiency of the ultrasonic waves decreases, and the flaw detection accuracy decreases.

In particular, when the object to be inspected is a pipe, the positional deviation between the projection point A and the transmission point B due to a small angular deviation of the flat vibrator 26 is larger than when the object is a flat plate, and the angle setting must be performed with greater accuracy. It was time consuming.

The first invention makes it possible to reliably obtain a predetermined ultrasonic projection angle and transmission angle without requiring severe angle adjustment of both probes, even with an extremely simple improvement, and the second invention The object of the present invention is to provide a method for easily, quickly, and reliably performing flaw detection on a pipe at a predetermined depth by transmitting ultrasonic waves in a predetermined manner.

In order to achieve the above object, the ultrasonic flaw detection device for the oblique transmission method according to the first invention has a transducer of a transmitting probe having a spherical shape or a shape centered on the projection point to the test object. In addition, the transducer of the receiving probe is configured to have a spherical shape or a shape close to the spherical shape centered on the point of transmission from the object.

Further, the oblique transmission flaw detection method according to the second invention is as follows:
An ultrasonic transmitting probe that has a vibrator configured in a spherical shape or a shape close to the spherical shape centered on the projection point to the pipe, and a vibration configured in a spherical shape or a shape close to the spherical shape centered on the transmission point from the pipe. The ultrasonic receiving probes each having a probe are placed so as to face the center or almost the center of the pipe.

Therefore, according to the first invention, the following effects can be obtained.

In the ultrasonic flaw detection device of the first invention, since the transmitting and receiving transducers have a spherical shape centered on the projection point or transmission point, the emitted ultrasonic waves are focused at the center of curvature. Later, the effective beam is directed in all directions, and the effective beam directed toward the receiving probe is efficiently received by the spherical receiving transducer.
In other words, according to the first invention, even if the mounting angles of both probes relative to the subject are slightly different, an effective beam always exists and can be received regardless of the refraction angle at the transmission point, so accurate angle adjustment is possible. unnecessary,
The efficiency of flaw detection work using the oblique transmission method can be improved.
In other words, since it is always possible to select the effective beam, there is no need to adjust the mounting angle even when a third probe is provided as shown in FIG. 4 of the embodiment described later. has the advantage of being able to change the flaw detection location.

Further, according to the second invention, the following effects can be obtained.

According to the second invention, when performing flaw detection on a pipe as a test object, both the transmitting and receiving probes are simply installed facing the center or almost the center of the pipe. Even if the transmitting probe and receiving probe are installed at different positions in the axial direction and circumferential direction of a pipe, which is a curved object, both probes can be installed uniformly. Flaw detection work using the oblique transmission method can be carried out efficiently. Even when changing the flaw detection depth, it is only necessary to change the relative distance between both probes, and there is an advantage that flaw detection at a predetermined depth can be performed easily and with high precision.

Next, embodiments of the present invention will be described in detail based on the drawings.

To configure an ultrasonic flaw detection device 2 for the oblique transmission method using an upright pipe 1 as a test object, as shown in FIGS. 1 and 2, one end is connected with a pin and the other end is connected. Two sets of holders 3, 3 provided with fittings are connected by rods 4, 4, and a curved member 5, 5 is installed across the rods 4, 4 so as to be able to change and fix the position freely. A transmitting probe 6 for projecting ultrasonic waves onto the pipe 1 and a receiving probe 7 for receiving ultrasonic waves transmitted through the pipe 1 can be fixed and changed in position in the circumferential direction of the pipe, respectively. The probes 6 and 7 are each composed of a transducer 8 and a box 9 in which the transducer is housed, and a water supply pipe 10 communicating with the box 9 is connected to connect the pipe 1 and the probe. While constantly filling and supplying water between the probes 6 and 7 and collecting leaked water into the water receiver 11, ultrasonic waves are projected from the transmitting probe 6 to the receiving probe 7, and the receiving probe Flaw detection is carried out based on the change in attenuation of transmitted ultrasonic waves received by the probe 7, and the flaw detection device 2 is suspended and connected to a self-propelled body 12 along the pipe 1, and continuously It is designed to allow flaw detection work to be carried out on a regular basis.

As shown in FIGS. 1 and 2, the self-propelled aircraft 12 includes a box-shaped frame 13 housing an electric motor M, and guide rollers 14, 14 whose diameter becomes smaller toward the center in the axial direction. Small diameter roller 1
A rocking bracket 16 with rollers 5... is provided, an endless belt 17 is wound around the group of rollers, cylinders 18 are attached on both sides of the frame 13 at intervals vertically apart, and the bent end A shaft 20 provided with a roller 19 is connected to the cylindrical body 18.
A spring 21 is provided so as to be slidable and rotatable against the upper and lower cylinders 18 and 1, and is provided with a spring 21 that draws and biases the roller 19 toward the frame 13.
A cross-sectional locking piece 22 is provided between the bending shafts 2 and 8, and a lever 23 that can be freely disengaged from the locking pieces 22 against the biasing force of the spring 21 is attached to the bending shaft 2.
0, and can be freely attached to and detached from the pipe 1 by rotating the rollers 19 around the cylindrical body 18, and can be remotely operated and stopped by the remote control device 24 for the motor M. It is designed to be controlled.

As shown in FIG. 3, the transducer 8 is constructed by placing the transducer 8 of the transmitting probe 6 at the projection point A onto the pipe 1, and the transducer 8 of the receiving probe 7.
is centered on the transmission point B from the pipe 1, and its excitation surface is formed into a spherical shape or a hollow hemispherical shape close to it. The receiving transducer 8 is configured to project ultrasonic waves having different transmission angles from one point of the center O to a point near the center.

According to the above configuration, as shown in FIG. 3, the installation distance L between both probes 6 and 7 is based on the flaw detection depth l.
Then, by setting the projection point A and the transmission point B of the ultrasonic waves to the pipe 1, and directing the transducers 8, 8 toward the pipe center Pa, the transducer center O is set at the projection point A.
Even if the operation is just to align with the transparent point B,
Ultrasonic waves having a predetermined projection angle θ can be projected from the transmitting transducer 8 to a predetermined projection point A, and the ultrasonic waves can be transmitted to a predetermined flaw detection depth l, and the transmitted ultrasonic waves can be transmitted to a predetermined flaw detection depth l. can be received by the receiving transducer 8 with a predetermined transmission angle θ', and by simply aligning the transducer center O with the projection point A and the transmission point B, there is no need to adjust the installation angle. Flaw detection at a predetermined depth l can be easily, quickly and accurately carried out without the need for

When changing the flaw detection depth l, when using the conventional flat vibrator 26, the projection angle θ is changed each time.
However, by changing the relative distance L between the two probes 6 and 7, flaw detection can be performed at an arbitrary depth l.

Furthermore, as shown in FIG. 4, by providing a third receiving probe 25 and switching the receiving probe 7 to the transmitting probe 6, or by By using the probe 25 as a transmitting probe, flaw detection around the pipe can be carried out continuously and efficiently without any need for angle adjustment.

Figures 5A to 5D show deformed structures of the vibrator 8, and Figure 5A shows the opening edge of the spherical vibrator 8 on both sides of the pipe 1 based on the spherical center O.
It is formed away from the outer peripheral surface of the
The one shown in FIG. 2B is one in which the opening edge is formed away from the outer surface of the pipe 1 with respect to its center. In addition, the ones shown in C and D of the same figure are those in which the opening edge is formed along the circumferential surface of the pipe.
In those shown in B, C, and D, the center O of the vibrator 8 is located on the outer peripheral surface of the pipe 1 by a box 9 in which the vibrator 8 is housed.

Although the pipe 1 is shown as the object to be examined, various objects such as plates and containers can be used as objects, and these are collectively referred to as the object 1 to be examined.

Incidentally, although reference numerals are written in the claims section for convenient comparison with the drawings, the present invention is not limited to the structure shown in the accompanying drawings.

[Brief explanation of the drawing]

The drawings show embodiments of the first and second inventions, in which Fig. 1 is an overall perspective view, Fig. 2 is a longitudinal cross-sectional side view of the self-propelled aircraft, Fig. 3 is an explanatory view of flaw detection, and Fig. 4 is an explanatory view of flaw detection. It is an explanatory view of the modification. FIGS. 5A to 5D are cross-sectional views showing deformed structures of the vibrator, respectively, and FIG. 6 is an explanatory diagram of flaw detection using a flat vibrator. 1... Object (pipe), 6... Ultrasonic transmitting probe, 7... Ultrasonic receiving probe, 8... Vibrator,
A... Projection point, B... Transmission point, O... Center, Pa
...Centered on pipes.

Claims (1)

[Claims] 1. A transmitting probe 6 that projects ultrasonic waves onto the subject 1.
This is an ultrasonic flaw detection device for the oblique transmission method, which includes a receiving probe 7 that receives ultrasonic waves transmitted through the object 1, and a transducer 8 of the transmitting probe 6. , the transducer 8 of the receiving probe 7 is configured to have a spherical shape with the projection point A to the subject 1 as the center O, or a shape close to it, and the transducer 8 of the receiving probe 7 as the center O with the transmission point B from the subject 1. An ultrasonic flaw detection device for oblique transmission method characterized by having a spherical shape or a shape close to it. 2. An ultrasonic transmitting probe 6 having a transducer 8 configured in a spherical shape or a shape close to the spherical shape whose center O is the projection point A to the pipe 1, and a spherical surface whose center O is the transmission point B from the pipe 1. An oblique angle of a pipe characterized in that the ultrasonic receiving probes 7 each having a transducer 8 configured to have a shape or a shape close to the shape are installed in a state in which each ultrasonic receiving probe 7 faces the center Pa or approximately the center of the pipe 1. Transmission flaw detection method.