JP4579770B2 - Ultrasonic flaw detector - Google Patents

Description

  The present invention relates to an ultrasonic flaw detector for inspecting the inside of a subject by observing the ultrasonic wave incident on the subject and reflected or transmitted through the inside of the subject.

  During the operation of ultrasonic flaw detection, the inspector grasps the probe (ultrasonic flaw detection probe) with one hand, scans the object (inspection object, object under test, test object), and holds the object with the other hand. In many cases, basically, both hands are used. In order to observe the flaw detection waveform displayed on the ultrasonic flaw detector in detail, in order to perform operations such as freezing of the displayed flaw detection waveform, the inspector once removes his hand from the probe and hands on the ultrasonic flaw detector main body. May stretch. This action may cause the probe to shake, flaw detection waveforms, and waveform quality to deteriorate. In addition, the worker is nervous and causes physical fatigue. Therefore, by using the remote function of the ultrasonic flaw detector and operating the switch attached to the probe, it is possible to perform the setting operation of the device at the probe without removing the hand from the probe. (For example, refer to Patent Document 1 and Patent Document 2).

  FIG. 7 shows the appearance of a conventional ultrasonic flaw detector, and FIG. 8 shows the internal configuration of the conventional ultrasonic flaw detector. The ultrasonic probe 4 (ultrasonic flaw detection probe) is provided with a switch 40 operated by an inspector. The piezoelectric element 41 transmits ultrasonic waves, enters the subject, and receives ultrasonic waves that have passed through the subject. A cable 6 for connection with the ultrasonic flaw detector 5 of the main body is connected to the connector 42 of the ultrasonic probe 4. The cable 6 includes a switch cable 60 that transmits a signal from the switch 40 to the ultrasonic flaw detector 5, a drive cable 61 that transmits a drive signal for driving the piezoelectric element 41, and a reception signal output from the piezoelectric element 41. It consists of. The switch cable 60 is connected to the ultrasonic flaw detector 5 via the switch cable connector 50 and the drive cable 61 via the drive cable connector 51.

When the inspector inputs an instruction such as freeze, the switch 40 is pressed. Then, the switch monitoring circuit 52 inside the ultrasonic flaw detector 5 detects that the switch 40 has been pressed, and outputs a signal indicating an instruction such as freeze to the signal processing circuit 53. The signal processing circuit 53 performs a predetermined process based on this signal, so that the inspector can perform a desired operation.
JP-A-9-56716 JP-A-11-56852

  As described above, conventionally, by providing a switch on the probe and remotely operating the ultrasonic flaw detector, it is possible for the inspector to perform the setting operation of the device without removing the hand from the probe. Two types of cables are required: a flaw detection signal cable and a switch operation signal cable. For this reason, there existed a problem that the handling (handling) of a cable worsened and the possibility of the disconnection of a cable increased.

  The present invention has been made in view of the above-described problems, and facilitates connection between the ultrasonic flaw detection probe and the main body of the ultrasonic flaw detection apparatus, and performs setting operation of the device without releasing the hand from the probe. An object of the present invention is to provide an ultrasonic flaw detection apparatus capable of performing the above.

  The present invention has been made to solve the above problems, and the invention according to claim 1 is directed to an ultrasonic flaw detection apparatus including an ultrasonic flaw detection probe that transmits and receives ultrasonic waves. An acoustic impedance changing means for changing an acoustic impedance of a region in the ultrasonic flaw detection probe through which a sound wave passes, and a detecting means for detecting a reflected wave from a region where the acoustic impedance has been changed by the acoustic impedance changing means; When the reflected wave is detected by the means, the ultrasonic flaw detection apparatus performs a predetermined process.

  According to a second aspect of the present invention, in the ultrasonic flaw detection apparatus according to the first aspect, a through hole is formed in a region in the ultrasonic flaw detection probe through which the transmitted ultrasonic wave passes, and the acoustic impedance The changing means is characterized in that two members having different acoustic impedances are coupled along the direction of insertion into the through hole, and the insertion distance into the through hole can be changed.

  According to the present invention, it is possible to change the acoustic impedance of the region through which the ultrasonic wave passes, and when the reflected wave from the ultrasonic flaw detection probe is detected, the ultrasonic flaw detection device performs a predetermined process. It is only necessary to prepare one type of cable, and it is possible to simplify the connection between the ultrasonic flaw detection probe and the main body of the ultrasonic flaw detection apparatus, and to perform the setting operation of the apparatus without removing the hand from the probe. It is done.

  The best mode for carrying out the present invention will be described below with reference to the drawings. FIG. 1 shows the appearance of an ultrasonic flaw detector according to an embodiment of the present invention. The ultrasonic probe 1 (ultrasonic flaw detection probe) transmits ultrasonic waves, enters the subject (test piece), and receives the ultrasonic waves passing through the inside of the subject. As an example, it is assumed that the ultrasonic probe 1 of the present embodiment is an oblique flaw detection probe that injects ultrasonic waves obliquely to a subject. On the side surface of the ultrasonic probe 1, a switch 10 (acoustic impedance changing means) that is pressed when performing a predetermined setting operation on the device is provided.

  The ultrasonic probe 1 and the ultrasonic flaw detector 2 of the main body are connected by a cable 3. The cable 3 transmits a signal for driving a piezoelectric element provided in the ultrasonic probe 1. The cable 3 is inserted into a connector 11 provided in the ultrasonic probe 1 and is inserted into a connector 20 provided in the ultrasonic flaw detector 2.

  Conventionally, a wedge for refracting an ultrasonic beam has been provided in an oblique flaw detection probe (see FIG. 9). The wedge is made of a resin such as polystyrene that can easily transmit ultrasonic waves. The wedge has a surface to which a piezoelectric element is attached and a surface to which a silencer damper is attached. When the ultrasonic wave emitted from the piezoelectric element propagates from the wedge to the subject, it is divided into a refracted wave mainly used for flaw detection and a reflected wave that is reflected in the wedge and is unnecessary for flaw detection. . A damper is affixed to the wedge to absorb and mute unwanted reflected waves.

  As shown in FIGS. 2A and 2B, a wedge 12 is provided inside the ultrasonic probe 1 of the present embodiment. The wedge 12 is provided with a piezoelectric element 13 and a damper 14. The piezoelectric element 13 transmits ultrasonic waves, enters the subject, and receives ultrasonic waves that have passed through the subject. That is, the piezoelectric element 13 converts the voltage signal input from the ultrasonic flaw detector 5 through the cable 3 into an ultrasonic wave, converts the vibration of the ultrasonic wave incident from the subject into a voltage signal, and To the ultrasonic flaw detector 5. The damper 14 absorbs unnecessary reflected waves.

  A through hole 15 (through hole) is provided in the middle of the sound axis that is silenced by the damper 14 in the wedge 12 through which the ultrasonic wave transmitted from the piezoelectric element 13 enters the subject. As shown in FIG. 3, a member 16 (acoustic impedance changing means) having the same diameter as that of the through hole 15 can be inserted into the through hole 15 so as to obtain acoustic coupling. The member 16 is for changing the acoustic impedance of the region where the ultrasonic wave passes, and is connected in series along the insertion direction of the through hole 15 (the axial direction of the member 16), and the two members 16a having different acoustic impedances. And 16b.

  The member 16a is made of a material having the same acoustic impedance as that of the wedge 12, and the member 16b is made of a material having an acoustic impedance greatly different from that of the wedge 12 (for example, a metal material such as Al or Fe). The length of each of the members 16a and 16b in the axial direction is substantially the same as the length of the through hole 15. The member 16 b is coupled to the switch 10, and the distance between the switch 10 and the wedge 12 is held by the spring 17 so that most of the through hole 15 is occupied by the member 16 a. That is, normally, the member 16 is locked by the spring 17 in a state where the member 16a is inserted into the through hole 15 (FIGS. 2A and 3A).

  The inspector can press the member 16 via the switch 10. When the switch 10 is pressed by the inspector, the spring 17 is contracted in conjunction with the switch 10, and the member 16 a is pushed out from the wedge 12 to the outside. The member 16 moves along the through-hole 15 in the direction to be moved. The insertion distance of the member 16 into the through hole 15 can be changed according to the amount of pressing. As a result, the member 16b having a large acoustic impedance different from the wedge 12 is positioned in the wedge 12 (FIGS. 2B and 3B). When the inspector releases the switch 10, the member 16 is urged by the spring 17 in the direction in which the member 16 b is pushed out of the wedge 12 and returned to the original position.

  When the member 16b having the same acoustic impedance as the wedge 12 is located in the wedge 12, a slight reflected wave is formed, but most of the ultrasonic waves are transmitted through the wedge 12, and the damper 14 is provided. The sound reaches the surface and is silenced by the damper 14. On the other hand, when the member 16b having a large acoustic impedance different from the wedge 12 is located in the wedge 12, most of the ultrasonic waves reflected by the contact surface between the wedge 12 and the subject are reflected by the member 16b. The light is reflected by the contact surface between the wedge 12 and the subject and reaches the surface on which the piezoelectric element 13 is provided.

  The propagation time from when the ultrasonic wave is transmitted until it returns can be found by calculation, and the reflected wave from the member 16b within a period different from the period during which the flaw detection signal based on the reflected wave from within the subject returns. Therefore, the reflected wave from the member 16b can be easily determined. Therefore, the ultrasonic flaw detector according to the present embodiment can detect a reflected wave having a predetermined amplitude or more with a gate function within a period in which the reflected wave from the member 16b returns. When the reflected wave is detected by the gate function, the inspector requests a preset function (freeze or the like), and the ultrasonic flaw detector performs a predetermined process necessary for the freeze or the like.

  FIG. 4 shows the internal configuration of the ultrasonic flaw detector according to the present embodiment. In the ultrasonic flaw detector 2, a pulsar / receiver 21, a signal processing circuit 22, and a gate circuit 23 (detection means) are provided. The pulser / receiver 21 outputs a voltage signal for driving the piezoelectric element 13. This voltage signal is input to the ultrasonic probe 1 via the cable 3 and applied to the piezoelectric element 13. The piezoelectric element 13 converts the voltage signal into an ultrasonic wave and transmits it. The reflected wave from the subject or member 16b is incident on the piezoelectric element 13, and the piezoelectric element 13 converts the vibration of the ultrasonic wave into a voltage signal and outputs it. This voltage signal is input to the pulser / receiver 21 of the ultrasonic flaw detector 2 through the cable 3.

  The voltage signal input to the pulsar / receiver 21 is output to the signal processing circuit 22 and the gate circuit 23. The signal processing circuit 22 performs processing such as amplification processing, filter processing, and peak hold processing on the flaw detection signal based on the reflected wave from the inside of the subject. The gate circuit 23 is a circuit that detects a reflected wave from the member 16b, and a predetermined operation is instructed when a signal having a predetermined voltage value or more based on the reflected wave from the member 16b is detected within a predetermined period. A signal indicating this is output to the signal processing circuit 22. Based on this signal, the signal processing circuit 22 performs predetermined processing such as preset freeze. Functions that can be set in advance include gain up, gain down, gate condition setting, etc. in addition to freeze.

  As shown in FIG. 5, after the transmission pulse 101 is applied to the piezoelectric element 13, the defect echo 103 based on the ultrasonic wave reflected by the defect portion inside the subject is detected. When the inspector presses the switch 10 and the member 16b is inserted into the through hole 15, the echo 102 based on the reflected wave from the member 16b is detected before the defect echo 103 is detected. 23.

  FIG. 6 shows a circuit configuration in the ultrasonic flaw detector. In FIG. 6, only the configuration for detecting a predetermined operation is shown, and the other configuration is omitted. The transmission pulse generator 201 to the request processing register 210 are provided in the ultrasonic flaw detector 2. The transmission pulse generator 201 generates a transmission timing signal. The piezoelectric element driving unit 202 uses the pulse input as a trigger to generate a voltage signal for causing the piezoelectric element 13 to vibrate to perform an ultrasonic wave generation operation, and outputs the voltage signal to the piezoelectric element 13. The piezoelectric element 13 generates an ultrasonic wave based on this voltage signal. The reflected wave received by the piezoelectric element 13 is converted into a voltage signal.

  The reception amplifier 203 amplifies and outputs a voltage signal based on the reflected wave. The gate voltage generator 204 generates a gate voltage that becomes a threshold voltage for detecting a predetermined operation. The comparator 205 compares the voltage amplified by the reception amplification unit 203 with the gate voltage generated by the gate voltage generator 204, and outputs a Hi or Low level signal based on the comparison result. For example, when the voltage amplified by the reception amplifier 203 is higher than the gate voltage, the comparator 205 outputs a Hi level signal. When the voltage is lower than the gate voltage, the comparator 205 outputs a Low level signal. Is output. The delay counter 206 performs counting for giving a predetermined delay. The delay counter 206 starts counting in synchronization with the pulse from the transmission pulse generator 201, and outputs a pulse signal to the WIDTH counter 207 after the predetermined counting is completed.

  The WIDTH counter 207 starts counting using this pulse signal as a trigger, and outputs a Hi level signal until the predetermined count ends. The WIDTH counter 207 outputs a low level signal while not counting. Signals output from the comparator 205 and the WIDTH counter 207 are input to the AND gate 208. The AND gate 208 outputs a signal obtained by multiplying two signals. As a result, when a voltage equal to or higher than the gate voltage is detected within a predetermined period, a high level signal is output from the AND gate 208 and input to the INT terminal of the CPU 209 as an interrupt signal. When the CPU 209 detects an interrupt signal, the CPU 209 refers to the request processing register 210 and performs predetermined processing such as freezing in accordance with the contents of processing written in the request processing register 210 in advance.

  As described above, according to the present embodiment, two members having different acoustic impedances are inserted into the ultrasonic flaw detection probe, and the acoustic impedance in the region through which the ultrasonic waves can be changed. The reflected wave from the ultrasonic flaw detection probe is detected in a period different from the period in which the wave is detected. When this reflected wave is detected, the ultrasonic flaw detector performs a predetermined process, so that the inspector can perform the setting operation of the device without releasing the hand from the probe. In addition, since only one type of cable for the flaw detection signal is used, the connection between the ultrasonic flaw detection probe and the main body of the ultrasonic flaw detection apparatus can be simplified, and the cable can be easily routed.

  As described above, the embodiments of the present invention have been described in detail with reference to the drawings. However, the specific configuration is not limited to these embodiments, and includes design changes and the like without departing from the gist of the present invention. . For example, the present invention may be applied to a vertical flaw detection probe, and the same effect can be obtained by the same structure and principle as those of the oblique flaw detection probe.

1 is an external view showing an external appearance of an ultrasonic flaw detector according to an embodiment of the present invention. 1 is a schematic cross-sectional view showing the structure of an ultrasonic flaw detection probe provided in an ultrasonic flaw detection apparatus according to an embodiment of the present invention. 1 is a schematic cross-sectional view showing the structure of an ultrasonic flaw detection probe provided in an ultrasonic flaw detection apparatus according to an embodiment of the present invention. It is a schematic block diagram which shows the internal structure of the ultrasonic flaw detector by one Embodiment of this invention. It is a reference figure showing the waveform of the signal processed in the ultrasonic inspection equipment by one embodiment of the present invention. It is a block diagram which shows the circuit structure of the ultrasonic flaw detector by one Embodiment of this invention. It is an external view which shows the external appearance of the conventional ultrasonic flaw detector. It is a schematic block diagram which shows the internal structure of the conventional ultrasonic flaw detector. It is a schematic cross section showing the structure of an ultrasonic flaw detection probe provided in a conventional ultrasonic flaw detection apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,4 ... Ultrasonic probe, 2,5 ... Ultrasonic flaw detector, 3,6 ... Cable, 10, 40 ... Switch, 11, 20, 42, 50, 51 ... Connector , 12 ... Wedge, 13, 41 ... Piezoelectric element, 14 ... Damper, 15 ... Through hole, 16, 16a, 16b ... Member, 17 ... Spring, 21 ... Pulsar / Receiver, 22, 53 ... Signal management circuit, 23 ... Gate circuit, 52 ... Switch monitoring circuit, 60 ... Switch cable, 61 ... Drive cable, 201 ... Transmission pulse generation 202 ... piezoelectric element drive unit, 203 ... reception amplification unit, 204 ... gate voltage generator, 205 ... comparator, 206 ... delay counter, 207 ... WIDTH counter, 208 ... AND gate, 209 ·· CPU, 210 ··· request processing register

Claims (2)

In an ultrasonic flaw detector equipped with an ultrasonic flaw detection probe that transmits and receives ultrasonic waves,
Acoustic impedance changing means for changing the acoustic impedance of a region in the ultrasonic flaw detection probe through which the transmitted ultrasonic waves pass;
Detecting means for detecting a reflected wave from a region where the acoustic impedance is changed by the acoustic impedance changing means;
An ultrasonic flaw detector characterized by performing a predetermined process when the reflected wave is detected by the detection means. A through hole is formed in a region in the ultrasonic flaw detection probe through which the transmitted ultrasonic wave passes,
The acoustic impedance changing means is characterized in that two members having different acoustic impedances are coupled along the direction of insertion into the through hole, and the insertion distance into the through hole can be changed. The ultrasonic flaw detector according to claim 1.

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