JP2585658B2 - Ultrasonic probe - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic probe, and more particularly, to an ultrasonic probe for detecting an object such as a pipe whose inspection surface has a curved surface using a plurality of ultrasonic beams. About the tentacles.

[Conventional technology]

As described in Japanese Patent Application Laid-Open No. 56-125661, a conventional composite ultrasonic probe has a transmitting oscillator and a receiving oscillator for a vertical beam sandwiched by a sound insulating plate, and a beam for an oblique beam. By disposing the two transmitting / receiving vibrators sandwiching the sound insulating plate, the vertical vibrator can be divided into two parts, and the oblique vibrator can be made a two-angle single search type. As described in JP-A-56-44842, a structure is adopted in which a transmitting oscillator and a receiving oscillator are arranged with a sound insulating plate interposed therebetween for both a vertical beam and an oblique beam, and all are divided into two. Was.

[Problems to be solved by the invention]

In the above-mentioned prior art, the known example in which the vibrator for angle beam is one-type is not a problem if the flaw detection surface is flat. However, if the flaw-detection surface has a curvature like a pipe, the following problems occur. Occurs. FIG. 4 shows a state of incidence of an oblique beam in the axial direction of a pipe in a composite type ultrasonic probe of a known example (one-search type).
Here, 16 and 17 are vertical oscillators, 18 and 19 are oblique oscillators, 20
Is piping, 21 and 22 are circumferential defects, 23 and 24 are oblique beams, 2
3 'and 24' are oblique beams reflected by defects and 21 and 22, respectively. The oblique beams 23 and 24 are incident on the pipe 20 in the axial direction. Since the oblique beams 23 and 24 are not incident from the center axis of the probe, they are refracted at the surface of the pipe and enter the pipe 20. The oblique beams 23 and 24 incident on the defects 21 and 22 having reflecting surfaces parallel to the circumferential direction are reflected in directions different from the incident direction (see oblique beams 23 ′ and 24 ′), and the oblique oscillator 18 ,
Since it does not return to 19, the defect detection sensitivity decreases.

In addition, in the method in which all transducers are divided into two parts, the sound field is different from that of a general one-type ultrasonic probe because the transducer for the oblique angle is divided into two parts. Atsuta.

(1) In the evaluation of the characteristics such as the refraction angle and the incident point of the ultrasonic probe, the method defined on the assumption of the conventional one-search type may not be applicable.

(2) The angle of refraction of the ultrasonic probe changes according to the path of the ultrasonic beam.

(3) The range of use may be limited due to the existence of the focusing range of the ultrasonic beam.

As one method for solving these problems, as shown in FIG. 6, a method in which all the vibrators 30, 31, and 32 are of a single type can be considered. Here, 29 is a shoe, 30 is a vertical oscillator 31, 32 is an oblique oscillator, 33 is a vertical beam, and 34 and 35 are oblique beams. However, in this method, in the vertical oscillator 30, due to the multiple reflection echoes 37 and 38 in the shot generated between the probe contact surface and the oscillator 30 as shown in FIG.
It cannot be evaluated except for the defect echoes generated in the flaw detection range 41 between 38, and has a defect that a dead zone 39 corresponding to the width of the multiple reflection echo 37 is generated. Here, 36 is the transmission pulse, and 40 is the propagation time in the show. This dead zone
39 becomes longer as the frequency of the transducer becomes lower, and the flaw detection range
41 narrows.

SUMMARY OF THE INVENTION An object of the present invention is to provide a composite probe capable of performing an ultrasonic inspection of an object having a curvature on a surface to be inspected such as a pipe in a satisfactory manner and capable of detecting a wide area.

[Means for solving the problem]

The above-mentioned object has a one-segment type characteristic by arranging the vibrator in a two-part structure and simultaneously transmitting and receiving simultaneously two oblique beam vibrators by electrically connecting them in parallel. However, the vertical beam vibrator can be achieved by a normal two-split type using one for transmitting and the other for receiving.

[Action]

The sound field of the oblique vibrator according to the present invention is a combination of sound fields when two vibrators are excited one by one.

By placing the vibrator in the center as much as possible, adjusting the width of the vibrator to an appropriate width according to the frequency of the vibrator, and adjusting the directivity when a single vibrator is excited to an appropriate spread In addition, the directivity of the synthesized sound field when two vibrators are excited can be optimized, and a characteristic close to a single search type can be obtained.

The vertical transducer is a two-piece type, but the two-piece type vertical probe has no problem of fluctuation of the refraction angle and the incident point, and there is no dead zone in the structure. There is an advantage of excellent detectability.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to FIGS.
This will be described with reference to FIGS. 5, 8, and 9.

FIG. 1 is an internal structural view of the embodiment, wherein 1 and 2 are a shear, 3 is a transmitting oscillator for a vertical beam 10, 4 is a receiving oscillator for a vertical beam 10, and 5 and 6 are first oblique beams 11. Transmitter / receiver vibrator, 7,8
Is a transducer for both transmission and reception for the second oblique beam 12, and 9 is a sound insulating plate. 5 and 6 are electrically connected in parallel and transmit and receive at the same time. The same applies to 7,8.

Next, simultaneous excitation of two vibrators will be described with reference to FIGS.

The directivity 14 of the ultrasonic beam of the probe changes according to the transducer frequency and the transducer width 13. FIG. 2 shows a change in the directivity 14 when the transducer width 13 is changed. When the vibrator width 13 is wide, the directivity 14 has a sharp characteristic as shown in (a), and as the vibrator width 13 is reduced, the characteristic becomes closer to non-directional. FIG. 3 shows the directivity 15 of the combined beam when two vibrators are excited at the same time. When the directivity of each beam is too sharp, the directivity 15 of the combined beam becomes bimodal as shown in FIG.

On the other hand, when the individual beams are close to non-directional, the directivity 15 of the combined beam becomes unimodal as shown in FIG. However, in this case, since the directivity is too broad, the defect resolution is reduced. Further, since the intensity of the ultrasonic wave is reduced, problems such as a decrease in defect detection sensitivity occur. Therefore, by adjusting the transducer width so that each beam has an appropriate directivity, the directivity 15 of the combined beam can be optimized as shown in FIG.

FIG. 5 shows the incident state of the oblique beam in the pipe axis direction in the present embodiment. According to the present embodiment, the oblique beam 2
The slacks 7, 28 are incident on the probe central axis, and are incident perpendicularly to the defect 25 having a reflecting surface parallel to the circumferential direction.
The ultrasonic beams 27 'and 28' reflected by the defect are reflected in the same direction as the incident direction and are received by the transducers 5, 6 or 7, 8 so that good defect detectability can be obtained.

FIG. 8 is an illustration of the transmission / reception status of the vertical vibrators 3 and 4 in this embodiment.

According to the present embodiment, since the vertical vibrator is of the two-part type, it receives only the echo 43 due to the leakage between the transmission and reception on the surface, and does not receive the multiple echo in the show, so that the flaw detection range 45 can be widened. it can. Here, 42 is the transmission pulse, and 44 is the propagation time in the show.

FIG. 9 is a modification of the embodiment, in which only one type of oblique beam is used. This is effective when it is not necessary to perform flaw detection using a plurality of oblique beams, and it is possible to reduce the size of the probe. it can. Here, 46 and 47 are shears, 48 and 49 are vertical oscillators, 5
0,51 is a bevel oscillator, 52 is a sound insulating plate, 53 is a vertical beam, 54
Is an oblique beam.

〔The invention's effect〕

ADVANTAGE OF THE INVENTION According to this invention, the defect can be detected favorably at the time of the ultrasonic flaw detection of a test object having a curved flaw detection surface.

[Brief description of the drawings]

FIG. 1 is a top view (a) and a side view (b) of a structural view of one embodiment of the present invention, FIGS. 2 and 3 are explanatory diagrams of beam directivity of one embodiment of the present invention, and FIG. FIG. 5 is an explanatory view of pipe flaw detection according to a conventional example, FIG. 5 is an explanatory view of pipe flaw detection according to one embodiment of the present invention, FIG. 6 is a top view and a side view of a structural diagram of a single probe composite probe, FIG. FIG. 7 is an explanatory diagram of the transmission / reception status of the vertical vibrator in the single probe composite probe, FIG. 8 is an explanatory diagram of the transmission / reception status of the vertical vibrator of the present invention, and FIG. 9 is another embodiment of the present invention. It is the top view and side view of a structural drawing. 1, 2… Show, 3… Transmitter oscillator, 4… Receiver oscillator, 5, 6, 7, 8… Transmitter / receiver oscillator, 9… Sound insulation plate, 10
…… Vertical beam, 11… First angle beam, 12… Second angle beam.

Continuing from the front page (72) Inventor Kenji Kumasaka 3-2-1 Sachimachi, Hitachi-shi, Ibaraki Hitachi Engineering Co., Ltd. (72) Inventor Kimio Kanda 3-2-1 Sachimachi, Hitachi-shi, Ibaraki Hitachi Engineering Co., Ltd. In-company (72) Inventor Kazuo Takaku 3-1-1, Sachimachi, Hitachi City, Ibaraki Prefecture Inside Hitachi, Ltd. Hitachi Plant (56) References JP-A-57-67399 (JP, A) JP-A-60-178349 (JP, A) JP-B-58-27459 (JP, B2)

Claims (1)

(57) [Claims] 1. A composite ultrasonic probe in which a plurality of transducers are arranged on a wedge to simultaneously perform flaw detection using vertical and oblique beams, wherein the arrangement of the movers is a two-part arrangement. An ultrasonic probe characterized in that it is used as it is for the vertical type, and two types of transducers sandwiching the sound insulating plate are electrically connected in parallel for the oblique angle type to provide a single-type characteristic.