JP2001349880A - Local immersion-type ultrasonic probe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To narrow the dead zone of a local immersion-type ultrasonic probe and to detect defects near a surface. SOLUTION: In the local immersion-type ultrasonic probe, a through-hole 1 is formed in the central part of a membrane 6, which is arranged in a part coming into contact with the surface of a material 3, to be flaw-sensed, at a cylinder 5 which ensures local immersion, and a water supply passage 9 which supplies liquid into the cylinder 5 is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a local immersion type ultrasonic probe.

[0002]

2. Description of the Related Art As a method (non-destructive method) for non-destructively inspecting a defective portion of a steel frame, a bridge, an oil tank, or the like, there is an inspection method using an ultrasonic flaw detector. In particular, when a flaw is detected for an internal defect of a thick steel plate, ultrasonic flaw detection using a local water immersion type ultrasonic probe is performed.

An example of such a local water immersion type ultrasonic probe is disclosed in Japanese Patent Application Laid-Open No. 7-218476. As shown in FIG. 3, this local water immersion type ultrasonic probe closes a lower part of a cylindrical body 21 with a film 22, attaches a vibrator 23 to an upper part of the cylindrical body 21, and places water inside the cylindrical body 21. In the local water immersion probe 24 satisfying
1 is provided with a local water supply port 25 for supplying water and an air vent hole 26 opened at a position of the cylinder 21 higher than the local water supply port 25.

When the flaw detection of the thick plate 27 is performed, the flaw detection is performed while a contact medium such as water is supplied between the cylinder 21 and the thick plate 27 from a contact medium discharge port 28 provided outside and below the cylinder 21. It is supposed to do it.

[0005]

However, the above-mentioned conventional local immersion ultrasonic probe has the following problems.

In ultrasonic flaw detection using a local water immersion type ultrasonic probe, longitudinal ultrasonic waves incident into the water from the transducer of the ultrasonic probe are required to ensure local water immersion. When a defect is present in the material to be inspected through the film body and the couplant supplied between the film body and the material to be inspected, and a defect is present inside the material to be inspected, the reflected wave is reflected by the ultrasonic wave. At the same time, the ultrasonic probe also receives the reflected wave from the surface of the film and the multiple reflected waves generated in the thin film and the couplant. In the above-described ultrasonic flaw detection using the conventional water immersion type ultrasonic probe, a film body for locally securing water immersion is formed between the pressure inside the cylinder and the cylinder and the material to be detected. Due to the pressure difference from the pressure of the supplied couplant, the dead zone becomes longer due to deformation, and defects near the surface of the material to be detected cannot be detected.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art. Since the film does not deform, the dead zone is shortened and a local defect which can detect a defect near the surface of the material to be inspected can be detected. It is intended to provide a water immersion type ultrasonic probe.

[0008]

A local water immersion type ultrasonic probe according to the present invention is provided at a central portion of a film body which is arranged at a portion of a cylindrical body for ensuring local water immersion which comes into contact with the surface of a material to be inspected. , And a means for supplying a liquid into the cylindrical body.

In the local immersion type ultrasonic probe according to the present invention, since the through hole is provided in the center of the membrane, the pressure of the liquid in the cylinder for ensuring local immersion, Since the pressure of the couplant supplied between the material and the material to be inspected can be made equal, the film is not deformed.

Accordingly, the width of the dead zone generated due to the deformation of the film body is reduced, and a defect near the surface of the material to be detected can be detected.

Since the liquid flowing out of the through hole during the flaw detection is supplied by the liquid supply means, local water immersion is always ensured.

[0012]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view showing an embodiment of a local immersion ultrasonic probe according to the present invention.

In the local water immersion type ultrasonic probe 1, the vibrator 2 and the ultrasonic wave emitted from the vibrator 2 pass through a water layer having a certain thickness and then enter the flaw detection material 3. Body 5 that accommodates water 4 that is provided to prevent water from leaking out and that is provided at the bottom of cylinder body 5 and that transmits ultrasonic waves 3
, A couplant supply passage 8 for supplying water from the outside as a couplant 7 between the membrane 6 and the material to be inspected 3, and water in the cylinder for supplying water into the cylinder 5. And a supply passage 9.

The film body 6 is made of a thin acrylic resin having a thickness of about 0.2 mm, and a through hole 10 having a diameter of about 5 mm is provided at the center of the film having an outer diameter of about 40 mm.

In the local water immersion type ultrasonic probe 1 of the present invention, the through-hole 10 is provided in the membrane 6, so that the pressure of the water 4 in the cylindrical body 5, the membrane 6, and the material to be inspected are Coupling medium 7 to be supplied to 3
Can be made the same as the pressure of water,
Are not deformed into convex portions or concave shapes.

Since the through hole 10 is provided in the membrane 6, the water 4 in the cylinder 5 may flow out. However, water is supplied from outside through the water supply passage 9 in the cylinder at any time. Therefore, the pressure of the water 4 in the cylinder 5 does not drop below the pressure of the couplant 7. Therefore, the dead zone accompanying the deformation of the film body 6 does not become long, and a defect near the surface of the material 3 to be detected can be detected.

FIG. 2 is a diagram showing a flaw detection waveform when a thick steel plate is flawed using a local water immersion type ultrasonic probe.
(A) shows the case where the local immersion ultrasonic probe 1 of the present invention is used, and (b) shows the case where the conventional local immersion ultrasonic probe is used. In both cases, 11 is a reflected wave from the surface of the thick steel plate, 12 is a reflected wave from the defect, and 13 is a waveform of a reflected wave from the bottom surface of the thick steel plate. As is apparent from this figure, when the local water immersion type ultrasonic probe 1 of the present invention is used, the dead zone W is short because the multiple reflection echo due to the deformation of the film body 6 does not occur. It can be seen that nearby defects can also be detected.

[0018]

According to the present invention, it is possible to accurately detect a defect near the surface of a material to be inspected.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of a local immersion ultrasonic probe according to the present invention.

FIG. 2 is a diagram showing a flaw detection waveform when a thick steel plate is flawed using a local immersion type ultrasonic probe, and FIG. 2 (a) shows a case where a local immersion type ultrasonic probe of the present invention is used. (B) is a case where a conventional local water immersion type ultrasonic probe is used.

FIG. 3 is a diagram showing an example of a conventional local immersion ultrasonic probe.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Local immersion type ultrasonic probe 2 Transducer 3 Material to be detected 4 Water 5 Cylindrical body 6 Film body 7 Coupling material 8 Coupling material supply passage 9 Water supply passage in cylinder 10 Through hole 11 Reflection from the surface of a thick steel plate Wave 12 Reflected wave from defect 13 Reflected wave from bottom of thick steel plate

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Noritaka Takamoto 1-2-1 Marunouchi, Chiyoda-ku, Tokyo F-term in Nihon Kokan Co., Ltd. 2G047 AA05 BA03 BB05 BC08 BC09 EA08 GA01 GE02 5D019 AA21 EE01 FF05

Claims (1)

[Claims] 1. A means for providing a through hole in a central portion of a film body disposed at a portion of a cylinder body for ensuring local water immersion in contact with a surface of a material to be inspected, and for supplying a liquid into the cylinder body. A local water immersion ultrasonic probe characterized by being provided.