JPH0434697B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to an array-type ultrasonic probe in which a large number of transmitters and receivers are arranged, and in particular, the present invention relates to an array type ultrasonic probe in which a large number of transmitters and receivers are arranged, and in particular, the present invention relates to an array type ultrasonic probe in which a large number of transmitters and receivers are arranged. The present invention relates to an array type ultrasonic probe that reduces the number of wires and transmission loss.

[Background of the invention]

Due to its structure, ultrasonic flaw detection of heat transfer tubes of steam generators (SG) used in nuclear reactors, etc., must be performed by inserting an ultrasonic probe inside the heat transfer tube.

However, as shown in Fig. 1, the heat exchanger tube 1 has a helical coil shape and is 80 m long, so a water tank 2 is installed above the helical coil, and a float 4 is attached to a drum 3 inside. A method of flaw detection is used in which a transmission cable 5 is wound and an array type ultrasonic probe 6 is inserted into the heat exchanger tube together with water. Therefore, the signal transmission cable from the externally installed ultrasonic flaw detector 7 to the array type ultrasonic probe 6 is as long as 120 m, and the attenuation of the transmitted signal is significant.

The array type ultrasonic probe 6 has the configuration shown in FIG. 2, and includes two transducer units 8,
9 and a circuit unit 10 for electronically switching the transmitter/receiver disposed thereon are connected by a bendable connecting portion 11. The switching operation of the transmitting and receiving wave elements will be briefly explained using FIG. Figure 3 shows how the transducers are arranged in one transducer unit 8, with 16 receivers arranged in the receiver side row _R1 , and 16 receivers arranged in the transmitter side row _T1 . 16 opposite
Transmitters are arranged.

Then, the 16 wave receivers in the wave receiver side row R ₁
The outputs of the counter 12 A ₀ , A ₁ ,
A ₂ and the analog switch 13 controlled thereby, the received signal is amplified by the preamplifier 14 and output in time series.

On the other hand, for the 16 transmitters in the transmitter side row _T1 , it is necessary to sequentially excite the transmitters corresponding to the selected receiver, one by one. Considering the method of using a pulser circuit, the number of signal lines of the cable 5 that connects the pulser circuit 15 on the ultrasonic flaw detector 7 side and the array type ultrasonic probe 6 is equal to the number of signal lines corresponding to the transmitter even if only for excitation pulses. However, since the outer diameter of the transmission cable increases, there is a drawback that the ease of inserting the probe is seriously affected. Moreover, the excitation pulse that reaches the array type ultrasonic probe 6 has a length of 120
It is attenuated by nearly 3 dB in the cable 5 of the transmitter side.
There is a concern that sufficient excitation of T ₁ will not be possible, resulting in a decrease in transmission sensitivity.

[Purpose of the invention]

The present invention aims to improve the sensitivity of ultrasonic flaw detection using an array type ultrasonic probe.

[Summary of the invention]

The structural features of the present invention include an array-type ultrasonic probe in which a plurality of transmitters and receivers are arranged, an ultrasonic flaw detector externally installed on the array-type ultrasonic probe, and an ultrasonic flaw detector that is synchronized with the ultrasonic flaw detector. In the ultrasonic flaw detection equipment comprising a pulser circuit that generates an excitation pulse to excite the wave transmitter, the pulser circuit is composed of a plurality of groups in which a part of the number of the wave transmitters is one group, and for each group, a plurality of pulser circuits provided, and a distribution circuit provided in a preceding stage of the plurality of pulser circuits to switch and distribute a trigger signal for driving the pulser circuits to some of the plurality of pulser circuits,
This is an array-type ultrasonic probe characterized by incorporating the above-mentioned pulser circuit and the above-mentioned distribution circuit, and eliminates the signal line for transmitting excitation pulses from the ultrasonic flaw detector to the array-type ultrasonic probe. Transmission loss in the path can be reduced, and even high-voltage excitation pulses can be switched and distributed to the wave transmitter by placing a distribution circuit in the front stage of the pulser circuit. This makes it possible to reduce transmission loss and use high-voltage excitation pulses without passing high voltage through the distribution circuit, thereby achieving long life and improved sensitivity.

[Embodiments of the invention]

The present invention will be described below with reference to the embodiments shown in the drawings. First, FIG. 4 shows an embodiment of the array-type ultrasonic probe according to the present invention, and shows only the transmission system necessary for explaining the present invention. , the receiving system is the third
The configuration is the same as that shown in the figure and is omitted.

In FIG. 4, an externally installed ultrasonic flaw detector 16
supplies the necessary power and synchronization signals to the pulser circuit 15 and distribution circuit 18 built in the array type ultrasonic probe 17 via the cable 5. The pulser circuit generates an excitation pulse at a predetermined repetition frequency based on the synchronization signal, and the pulser circuit 15
The excitation pulse is input to a distribution circuit 18 provided at a subsequent stage. The distribution circuit 18 is, for example, a high voltage IC.
It is composed of switches (or crosspoint switches used in telephone exchanges, etc.), PIN diode switches, etc., and can distribute input signals to multiple channels, and by applying a predetermined bias signal. Therefore, the input signal can be connected to any channel. Therefore, by applying a bias signal to each channel of the distribution circuit 18 in time series based on the synchronization signal, an excitation pulse is sequentially applied to each transmitter in the transmitter row _T1 , and the excitation pulse is sequentially applied to each transmitter in the transmitter row _T1. Ultrasonic waves can be transmitted in chronological order from

On the other hand, the reception system in the array type ultrasonic probe 17 is similar to the content explained in _FIG . The wave elements are sequentially switched one by one by an analog switch so as to correspond to each channel of the wave element side row _T1 . Thus, 1~i
The transducer up to the channel sequentially transmits and receives ultrasonic waves in chronological order to detect flaws all around the tube.
Although the wave transmitter side rows in FIG. 4 and subsequent figures are shown arranged in a plane for convenience, in the case of in-tube insertion type flaw detection, they are arranged in an annular shape as in FIG. 3.

That is, by incorporating the pulser circuit 15 and the distribution circuit 18 into the array-type ultrasonic probe 17, signal lines for excitation pulses corresponding to the number of channels are no longer required, and the outer diameter of the cable 5 can be made thinner. The ultrasonic probe 17 can be smoothly sent over the entire length of the tube.

However, in FIG. 4, the distribution circuit 18 uses a high-voltage IC switch or a PIN diode switch, so in the case of a steeply falling excitation pulse (fall time: 20 to 30 ns), if the pulse voltage is 300 V or more, Normal distribution of excitation pulses becomes impossible.

Therefore, FIG. 5 shows an embodiment of the present invention in which the excitation pulse can be normally distributed even if the excitation pulse voltage is 300 V or more.

In FIG. 5, an array type ultrasonic probe 17
A built-in distribution circuit 18 is provided in the front stage of the pulser circuit 15 consisting of m pulsers,
Ultrasonic flaw detector 16 installed externally via cable 5
The distribution circuit 18 sequentially switches and distributes the trigger signals transmitted from the distribution circuit 18. Therefore, P ₁ to _{P 4} of the pulser circuit 15 generate excitation pulses in time series at a predetermined period.

Note that the voltage level of the trigger signal is generally about several tens of volts from TTL, and the voltage level of the trigger signal is generally about several tens of volts from TTL.
The voltage level of the excitation pulse generated at 5 can be easily obtained in the range of 100 to 1000V in FIG.

Each pulser P ₁ , P ₂ , P ₃ of the pulser circuit 15,
Each of P ₄ is connected to n (4 in the figure) transmitters, and each time one pulser generates an excitation pulse, an ultrasonic beam is transmitted from multiple transmitters connected to that pulser. Sent simultaneously.
For this reason, m groups consisting of one pulser and n wave transmitters are repeatedly driven in time series.

Thus, in the array-type ultrasonic probe 17 as a whole, as shown in FIG. 6, which shows the relationship between the channel numbers of the transmitter and receiver and the scanning order, there is one receiver in each row from channels 1 to i. Although the transmitter arrays are switched in sequence, the transmitter arrays ensure that the transmitter element corresponding to the selected receiver in the receiver array is excited.
For example, when the receiver of channel No. 1 is selected, channels No. 1, 5,
When the ultrasonic beam is transmitted from the transmitter of channel No. 9, i-3 and the receiver of channel No. 2 is selected, the ultrasonic beam is transmitted from the transmitter of channel No. 2, 6, 10, i-2. A beam is sent out. Therefore,
In actual ultrasonic flaw detection, the transmitter that corresponds to the channel of the selected receiver among the transmitter side rows always contributes, and interference caused by the ultrasonic beams sent out from other transmitters is caused by the transmitters that are excited at the same time. This can be avoided by spacing them apart from each other.

As a result, the configuration shown in Fig. 5 allows the cable 5 to have a thin outer diameter, and also allows a relatively high-voltage excitation pulse of 300 V or more to be applied to the transmitter side row, making it possible to realize suitable ultrasonic flaw detection. .

FIG. 7 shows another embodiment of the array type ultrasonic probe according to the present invention, which is suitable for detecting different types of defects all at once in a single flaw detection process.

In FIG. 7, an array type ultrasonic probe 17
In this example, N systems of wave transmitter arrays with different detection targets are incorporated (of the three systems A, B, and C, only each wave transmitter side array is shown).

A distribution circuit 18 built into the array type ultrasonic probe 17 is provided before the pulser circuit 15 consisting of n pulsers, and receives a trigger signal transmitted from the externally installed ultrasonic flaw detector 16 via the cable 5. are sequentially switched and distributed by the distribution circuit 8. Therefore, each pulser of the pulser circuit 15 sequentially generates excitation pulses in a time-series manner at a predetermined period.

Pulsars P ₁ , P ₂ , P ₃ , P ₄ of the pulser circuit 15
are connected to n (4 in the figure) wave transmitters from among the wave transmitter side rows of each system,
Every time one pulser generates an excitation pulse, ultrasonic beams are simultaneously sent out from four transmitters in each system connected to that pulser. Therefore, N systems each consisting of m groups each consisting of n transmitters are driven in parallel, and each group within each system is switched in time series to generate an ultrasonic beam.

As a result, the array-type ultrasonic probe 17 can reduce the outer diameter of the cable 5 from the externally installed ultrasonic flaw detector 16 to the probe, so it can easily detect several types of defects while maintaining good insertion into the test tube. It becomes possible to detect flaws at high speed.

In addition, in this example, an array-type ultrasonic probe that is inserted into the test tube for flaw detection is described.
Since the present invention can reduce the number of signal lines in a cable and reduce transmission loss in the cable, it can be effectively applied to various other array type ultrasonic probes.

〔Effect of the invention〕

As explained above, according to the present invention, an array-type ultrasonic probe includes a pulser circuit that generates an excitation pulse for exciting a wave transmitter, and a distribution circuit that distributes the excitation pulse to the wave transmitter. This eliminates the need for a signal line for transmitting excitation pulses from the ultrasonic flaw detector to the array-type ultrasonic probe, which allows the outer diameter of the cable to be reduced, making it easier to insert the array-type ultrasonic probe into the pipe. can be carried out. In addition, since the excitation pulse is generated within the array type ultrasonic group, transmission loss in the cable in the transmitting system is reduced, and the overall weight of the cable is reduced, making it easier to handle. By placing a distribution circuit in the front stage of the pulser circuit, even high-voltage excitation pulses can be switched and distributed to the transmitter. For this reason, it is possible to reduce transmission loss and use high-voltage excitation pulses without passing high voltage through the distribution circuit, achieving long life and improving sensitivity, making it suitable for flaw detection using array-type ultrasonic probes. It has the effect of realizing

[Brief explanation of drawings]

Fig. 1 is a block diagram for explaining an application example of an array type ultrasonic probe, Fig. 2 is a conceptual block diagram of an array type ultrasonic probe, and Fig. 3 is a circuit block diagram of a conventional array type ultrasonic probe. , FIG. 4 is a configuration diagram of a transmission system for an array type ultrasound probe devised by the inventor of the present invention, and FIG. 5 is a configuration diagram of a transmission system for an array type ultrasound probe according to an embodiment of the present invention.
FIG. 6 is a diagram showing the relationship between channel numbers and scanning order of the transmitter and receiver in the embodiment shown in FIG. 5, and FIG. 7 is a transmission system for an array-type ultrasonic probe according to another embodiment of the present invention. FIG. T ₁ ... Transmitter side row, R ₁ ... Receiver side row, 5...
... Cable, 15 ... Pulsar circuit, 16 ... Ultrasonic flaw detector, 17 ... Array type ultrasonic probe,
18...Distribution circuit.

Claims (1)

[Claims] 1. An array-type ultrasonic probe in which a plurality of transmitters and receivers are arranged, an ultrasonic flaw detector installed externally on the array-type ultrasonic probe, and excitation of the transmitter in synchronization with the ultrasonic flaw detector. In an ultrasonic flaw detection equipment comprising a pulser circuit that generates an excitation pulse, the pulser circuit is composed of a plurality of groups, each group being a part of the number of the transmitters, and a plurality of pulsers provided for each group. circuit, and a distribution circuit that is provided upstream of the plurality of pulser circuits and switches and distributes a trigger signal for driving the pulser circuits to a part of the plurality of pulser circuits, wherein the pulser circuit and the distribution circuit are connected to each other. An array-type ultrasonic probe characterized by having a built-in.