Method for detecting deterioration of transducers of array probe

Abstract

To provide a method for detecting deterioration of transducers of an array probe.SOLUTION: In an array probe 1 in which a plurality of transducers 11 is caused to oscillate at predetermined timing to form a flaw detection beam, a calibration gate X is set in a region where a surface-reflected wave signal portion S1 appears in a received signal S of a reflected wave obtained when each transducer 11 is caused to oscillate individually, and an evaluation gate Y is set in a region other than the calibration gate X, the presence or absence of deterioration of the transducer 11 is detected depending on whether the magnitude of the received signal S in the evaluation gate Y when the received signal S is amplified such that the maximum value of the surface-reflected wave signal portion S1 in the calibration gate X becomes a predetermined value, becomes equal to or greater than a predetermined threshold value Th.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a method for detecting deterioration of transducers in an array probe. [Background technology]

[0002] An array probe generates a flaw detection beam by oscillating multiple transducers at a predetermined time interval, and because multiple transducers are in operation, the flaw detection beam itself is still formed even if some of the transducers are deteriorated, but the detection ability is reduced.

[0003] Therefore, Patent Document 1 shows a method in which some of the vibrators are excited, and the reflected waves from the surface or bottom of the object are received by all of the vibrators, and deterioration is detected by determining whether the magnitude of the received signal from each vibrator has returned to its previous magnitude or has decreased. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 62-194456 Summary of the Invention [Problem to be solved by the invention]

[0005] However, even if the deterioration of the vibrator is compared with the magnitude of the previous received signal, there was a problem in that the deterioration of the vibrator could not be reliably detected because the magnitude of the received signal is actually affected by fluctuations in the material type of the object, the contact medium, the contact distance, the temperature, etc.

[0006] SUMMARY OF THE INVENTION The present invention is intended to solve such problems, and has as its object to provide a transducer deterioration detection method that can reliably detect deterioration of transducers in an array probe. [Means for solving the problem]

[0007] In order to achieve the above object, in the first invention, in an array probe (1) that forms a flaw detection beam by oscillating a plurality of transducers (11) at a predetermined timing, a calibration gate (X) is set in an area where a surface reflected wave signal portion (S1) appears in a received signal (S) of a reflected wave when each transducer (11) is oscillated independently, and an evaluation gate (Y) is set in an area other than the calibration gate (X). When the received signal (S) is amplified so that the maximum value of the surface reflected wave signal portion (S1) in the calibration gate (X) becomes a predetermined value, the presence or absence of deterioration of the transducer (11) is detected based on whether the magnitude of the received signal (S) in the evaluation gate (Y) is equal to or greater than a predetermined threshold (Th).

[0008] In the first aspect of the present invention, it is possible to reliably detect whether the transducer has deteriorated by determining whether the received signal within the evaluation gate exceeds the threshold value.

[0009] In the second invention, in the first invention, in an array probe (1) that forms a flaw detection beam by oscillating a plurality of transducers (11) at a predetermined timing, a calibration gate (X) is set in an area where a surface reflected wave signal portion (S1) appears in a received signal (S) of a reflected wave when each transducer (11) is oscillated independently, and an evaluation gate (Y) is set in an area other than the calibration gate (X), and when the received signal (S) is amplified so that the maximum value of the surface reflected wave signal portion (S1) in the calibration gate (X) becomes a predetermined value, the degree of deterioration of the transducer (11) is detected according to the magnitude of the received signal (S) in the evaluation gate (Y).

[0010] In the second invention, the degree of deterioration of the vibrator can be reliably detected from the magnitude of the received signal in the evaluation gate.

[0011] The symbols in parentheses above indicate, for reference, the correspondence with specific means described in the embodiments to be described later. [Effects of the Invention]

[0012] As described above, according to the transducer deterioration detection method of the present invention, deterioration of the transducers of the array probe can be reliably detected. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a diagram showing the overall configuration of a round bar flaw detector equipped with an array probe, in which deterioration is detected by the method of the present invention. [Figure 2] FIG. 10 is a diagram showing the waveform of a received signal after amplification when the transducer is normal. [Figure 3] FIG. 10 is a diagram showing the waveform of a received signal after amplification when the transducer is damaged. [Figure 4] FIG. 1 is a diagram showing the overall configuration of a round bar flaw detection device equipped with an array probe during normal flaw detection. DETAILED DESCRIPTION OF THE INVENTION

[0014] The embodiments described below are merely examples, and various design improvements made by those skilled in the art without departing from the gist of the present invention are also included in the scope of the present invention.

[0015] 4 shows the case where a round bar is inspected using an array probe, and the array probe 1 has multiple (e.g., 128) transducers 11 arranged in a roughly arc shape toward the outer periphery of the round bar located underwater. The array probe 1 is connected to a transmitting / receiving circuit 31 in the flaw detection device 3, and a predetermined number (e.g., 32) of transducers 11 are sequentially excited by a transmission signal simultaneously or with a predetermined time difference, thereby forming a desired flaw detection beam that is focused inside the bar 2.

[0016] The reflected waves of the flaw detection beam reflected by the surface 2a of the round bar 2 or by internal flaws are received by each transducer 11 and input as a received signal to the transmitting / receiving circuit 31, where they are amplified so that the maximum value of the surface reflected wave signal is 80% of full scale, for example, and then A / D converted and input into a computer (not shown) in the flaw detection device 3. In this case, even if one or more of the transducers 11 are deteriorated (including broken), the flaw detection beam itself is formed, so the deterioration of the transducers 11 is not recognized, and the reliability of flaw detection is impaired.

[0017] Therefore, in this embodiment, transducer deterioration detection is performed prior to flaw detection. For transducer deterioration detection, the flaw detection conditions are changed to single-element excitation as shown in Figure 1. That is, the excitation of each transducer 11 of the array probe 1 is switched to be performed independently. Then, in the received signal obtained by exciting a single transducer 11 and receiving the reflected wave of the flaw detection wave output by that transducer 11, a calibration gate X (see Figure 2) is set in the time domain where the surface reflected wave signal portion appears, and an evaluation gate Y is set in the time domain other than the calibration gate X (afterward in this embodiment).

[0018] 2 shows an example of the received signal S when the transducer 11 is normal. In this case, when a reflected wave is received by the transducer 11, a surface reflected wave signal portion S1 appears in the received signal S, and the entire received signal is amplified by the transmitter / receiver circuit 31 so that the maximum value of the surface reflected wave signal portion S1 in the calibration gate X is 80% of full scale. With this amplification, the magnitude of the received signal S is sufficiently smaller than the preset threshold value Th in the evaluation gate Y, where only the noise signal portion appears (i.e., the surface reflected wave signal portion S1 does not appear).

[0019] On the other hand, if the vibrator 11 is deteriorated and damaged, the surface reflected wave signal portion S1 does not appear in the received signal S, and only a small noise signal portion appears in the calibration gate X. Therefore, when the maximum value of the noise signal portion is amplified in the transmission / reception circuit 31 to 80% of full scale, the entire received signal S is greatly amplified (FIG. 3), and its magnitude greatly exceeds the threshold value Th in the evaluation gate Y. This detects that the vibrator 11 is damaged.

[0020] In this way, it is possible to sequentially and reliably detect whether the oscillator 11 is damaged or not by determining whether the received signal S in the evaluation gate Y is greater than the threshold value.

[0021] If the vibrator 11 is not damaged but has deteriorated, the surface reflected wave signal portion appearing in the received signal S will be relatively smaller than when it is normal. Therefore, in order to make the maximum value of the surface reflected wave signal portion S1 in the calibration gate X 80% of full scale, the amplification degree of the received signal S in the transmission / reception circuit 31 becomes relatively larger accordingly, thereby amplifying the received signal S as a whole. Therefore, the degree of deterioration of the vibrator 11 can also be detected from the magnitude (or the amplification degree at this time) of the received signal S (noise signal portion) in the evaluation gate Y. In this case, if the magnitude (or the amplification degree at this time) of the received signal S (noise signal portion) in the evaluation gate Y is recorded, the degree of deterioration can be relatively evaluated.

[0022] 1...array probe, 11...oscillator, S...received signal, S1...surface reflected wave signal section, Th...threshold value, X...calibration gate, Y...evaluation gate.

Claims

1. In an array probe that forms a flaw detection beam by oscillating a plurality of transducers at a predetermined timing, a calibration gate is set in an area where a surface reflected wave signal portion appears in the received signal of the reflected wave when each transducer is oscillated independently, and an evaluation gate is set in an area other than the calibration gate, and when the received signal is amplified so that the maximum value of the surface reflected wave signal portion in the calibration gate becomes a predetermined value, a method for detecting deterioration of the transducer in an array probe is provided, the method comprising the steps of:

2. A method for detecting deterioration of a transducer in an array probe, in which a plurality of transducers are operated to oscillate at a predetermined timing to form a flaw detection beam, a calibration gate is set in an area where a surface reflected wave signal portion appears in the received signal of the reflected wave when each transducer is operated to oscillate independently, and an evaluation gate is set in an area other than the calibration gate, and when the received signal is amplified so that the maximum value of the surface reflected wave signal portion in the calibration gate becomes a predetermined value, the method detects the degree of deterioration of the transducer according to the magnitude of the received signal in the evaluation gate.

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