JPH0554910B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an apparatus for non-destructively inspecting the inside of a material using ultrasonic waves.

[Conventional technology]

As a means of finding defects in solid objects such as metals, ultrasonic waves are injected into the material, and the waves reflected from the defects (hereinafter referred to as echoes) are captured and displayed on a display such as a cathode ray tube, thereby determining the size of the defect and the material. There is an ultrasonic flaw detector as a device for measuring the position of defects inside.

Conventionally, an ultrasonic flaw detection device as shown in FIG. 3 has been proposed as this type of device. In the figure, 1 is a synchronization section that outputs the synchronization signal necessary for each circuit, 2 is a transmission section that generates a transmission signal based on the output signal from synchronization section 1, and 3 is a frequency that varies the transmission frequency of transmission section 2. A variable circuit, 4, a frequency setting means for setting a frequency to the frequency variable circuit 3, 5, generating ultrasonic waves based on the transmission signal from the transmitter 2, causing the ultrasonic waves to enter the material to be inspected, and transmitting the ultrasonic waves from the material to be inspected. 6 is probe 5, which captures the echo of and converts it into an electrical signal.
A receiving unit 7 amplifies the electrical signal from the receiving unit 6
This is a display device that displays the output signal of the

Since conventional ultrasonic flaw detection equipment is configured as described above, the frequency has to be manually set by a human who judges the echoes displayed on the display.

[Problem that the invention seeks to solve]

Conventional ultrasonic flaw detection equipment has a manual frequency setting as mentioned above, so for example, 4MHz at 0.1MHz pitch.
When changing the frequency from 5MHz to 5MHz, it is necessary to make judgments on the display and set the frequency 10 times, and it is troublesome to have to memorize the best setting value, and erroneous settings may occur. There was a problem that it was not possible to transmit at the optimum frequency for material inspection.

This invention was made to solve these problems.It has a peak hold section, a sample hold section, a comparison section and a counter section, and automatically varies the optimum frequency and maintains it. The purpose of this invention is to obtain an ultrasonic flaw detection device that can transmit at a suitable transmission frequency.

[Means for solving problems]

The ultrasonic flaw detection device according to the present invention includes a frequency variable circuit for varying the transmission frequency and a frequency setting means,
A peak hold section that holds the peak value of the received echo, a sample hold section that samples and holds the peak hold signal, a comparison section that compares the sample hold signal and the peak hold signal, and a comparison section that counts the output signal of the comparison section and calculates the frequency. The counter section outputs count data to a setting means.

[Effect]

In this invention, the output signal of the receiving section is peak-held by the gate signal of the gate generation section, the peak-held signal is sampled and held by the output signal of the synchronization section, and the peak-held signal and the sample-held signal are The transmission frequency is variably set depending on the magnitude relationship with the

〔Example〕

FIG. 1 is a diagram showing an embodiment of an ultrasonic flaw detection apparatus according to the present invention. In FIG. 1, 1 to 6 are the same as those shown in FIG. Reference numeral 8 denotes a gate generating section that generates a gate for extracting the output signal of the receiving section 6 in synchronization with the output signal of the synchronizing section 1; 9 indicates the receiving section 6;
10 is a sample hold section that samples and holds the output signal of the peak hold section 9; 11 is a comparison between the output signal of the peak hold section 9 and the output signal of the sample hold section 10; A comparison section 12 is a counter section that counts the output signal of the comparison section 11 and outputs count data to the frequency setting means.

Next, the operation of the above embodiment will be explained with reference to FIGS. 1 and 2.

In the “1” section of the output signal CLPRF of the synchronizer 1 shown in FIG. 2, the output signal of the frequency variable circuit 3 is
CLTW has a time width of to. The transmitter 2 outputs a transmit signal corresponding to the time to of the output signal CLTW of the frequency variable circuit 3, converts it into an ultrasonic wave with the probe 5, amplifies it with the receiver 6, and converts the output signal (frequency
_RO , amplitude e ₁ ) to obtain sig. The output signal CLG of the gate generator 8 outputs a signal having a constant delay time _GS and a constant time width _GL for each output signal CLPRF of the synchronizer 1. The peak hold section 9 is the gate generation section 8
The receiver 6 present at the time GL of the output signal CLG of
The output signal sig of is extracted to obtain CLP/H having an output voltage e ₁ ' proportional to the peak value e ₁ . The sample hold section 10 receives the L output signal CLPRF of the synchronization section 1.
The output signal of the peak hold section 9 at the time of the level
Sampling CLP/H and output signal of synchronization section 1
At the same time as CLPRF moves to H level, it is held and e ₁ ″ is obtained.
Compare the output signal CLS/H of 0 in the hold interval, and if CLS/H<CLP/H, the output signal CLC
It is configured to obtain the following. The counter section 12 counts the output signal CLC of the comparison section 11 and outputs +1 data to the frequency setting means 4 at the time when the output signal CLPRF of the synchronization section 1 is at L level.

The above operation is performed as the output signal of the peak hold section 9.
CLP/H and output signal of sample hold section 10
CLS/H is CLP/H = CLS/H or CLP/
Variable (in the above embodiment, the output signal sig level of the receiving section 4 is e ₁
<e ₂ , e ₂ > e ₃ ), and since the output signal CLC of the comparator 11 is not output thereafter, the counter unit 12
The output data of is held and the frequency variable circuit 3
The output signal CLTW maintains a state having a time of t ₂ and is output to the transmitter 2.

In the above embodiment, the output data of the counter section 12 is held in a state of +1 from the optimum frequency (at the time width of t ₁ of the output signal CLTW of the frequency variable circuit 3), but the frequency setting at a pitch of 0.1 MHz If so, there is no difference at all.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to automatically set the optimum transmission frequency for the material to be inspected, thereby eliminating the hassle and erroneous setting of the optimum frequency.

Moreover, this has features such as being able to avoid deterioration of S/N due to the material to be inspected and phase interference in the vicinity of the probe, which is seen in the case of a fixed frequency type flaw detection device.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an ultrasonic flaw detector according to the present invention, FIG. 2 is an explanatory diagram of the operation of the ultrasonic flaw detector according to the present invention, and FIG. 3 is a block diagram of a conventional ultrasonic flaw detector. In the figure, 1 is a synchronization section, 2 is a transmitter, 3 is a variable frequency circuit, 4 is a frequency setting means, 5 is a probe,
6 is a receiver, 7 is a display, 8 is a gate generator, 9
1 is a peak hold section, 10 is a sample hold section, 11 is a comparison section, and 12 is a counter section.
Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] 1 a synchronization section that generates a predetermined repetition frequency;
a transmitting section that generates a transmission signal based on the output signal of the synchronizing section; a frequency variable circuit that varies the transmission frequency of the transmitting section; a frequency setting means that sets a frequency to the frequency variable circuit; A probe that converts a transmitted signal into an ultrasonic signal and causes the ultrasonic wave to enter the material under test, and converts a reflected wave from the test material into an electrical signal, and amplifies the electrical signal from the probe. a receiving section; a gate generating section that generates a gate for extracting the output signal of the receiving section based on the output signal of the synchronizing section; and a peak hold that peak-holds the output signal of the receiving section using the gate signal of the gate generating section. Department and
a sample hold section that samples and holds the output signal of the peak hold section using the output signal of the synchronization section; and a sample hold section that compares the output signal of the sample hold section and the output signal of the peak hold section, and selects the output signal of the peak hold section. 1. An ultrasonic flaw detection device comprising: a comparison section that outputs a predetermined signal when .