SU725018A1 - Ultrasonic flaw detector - Google Patents

Description

one

The invention relates to the field of non-destructive testing by an ultrasonic method and can be used in various parts of the machine building industry in the course of defectoscopy of materials.

A ultrasonic flaw detector is known, comprising a synchronizer, a probe pulse generator, a sawtooth generator, and a source of blocking voltage.

The flaw of the flaw detector is its low control accuracy, since it does not allow for equalizing the sensitivity of signals from defects.

The closest to the invention in technical essence and the achieved result is an ultrasonic flaw detector containing serially connected synchronizer, probe pulse generator, transducer, amplifier and indicator, pulse width former and gating pulse generator, the output of which is connected to the input of indicator 2.

A disadvantage of the known flaw detector is low control accuracy, since it does not allow to level the flaw detector sensitivity when checking thick-walled products.

The aim of the invention is to increase the accuracy of the control.

For this, the proposed flaw detector is equipped with a saw-tooth voltage generator connected between the transducer and the pulse width former, and a blocking voltage source connected between the amplifier and the pulse width former, the pulse width former input is connected to the synchronizer output, and the gate generator input.

FIG. 1 shows a block diagram of an ultrasonic flaw detector; in fig. 2 - time diagrams showing the work of the scheme.

The ultrasonic flaw detector contains a synchronizer 1 connected in series, a probe pulse generator 2, a transducer 3, an amplifier 4 and an indicator 5, a pulse width former 6, a strobe pulse generator 7, the output of which is connected to the indicator input 5, a sawtooth voltage generator 8 and a pulse shaper 6, a blocking voltage source 9 connected between amplifier 4 and

shaper b pulse duration, and a generator 10 connected between synchronizer 1 and indicator 5.

The input of the driver 6 for the duration of the pulses is connected to the output of the synchronizer 1, and the output to the generator input of the 7 strobe pulses.

Ultrasonic flaw detector works as follows ..-. .

The synchronizer 1 pulses 11 (see Fig. 2) starts the sweep generator 2, generating pulses 12 of the sawtooth voltage, which are fed to the horizontal deflecting plates of the indicator 5. Synchronizer 1 also starts the probe pulses generator 2, which pulses 13 the piezoplate of the converter 3. On piezoplastin simultaneously affects. The sawtooth voltage 14 coming from the generator 7, which additionally polarizes the piezoplate, increases the sensitivity of the transducer 3. Therefore, each subsequent impulse 13 sounds an ever deeper layer, so throughout the whole front edge of the saw (impulse 14), the duration of which is n periods of the probe pulse 13, where. Ultrasonic vibrations propagate in the product, are reflected from defects and return to the transducer 3. The received signal through the amplifier 4 is fed to the indicator 5. The trailing edge (the positive and negative part of pulse 14) will polarize the piezoelectric plate, which returns to its original state and the next no-layer control. The operation of the sawtooth generator 8 is controlled by a pulse width driver 6, which determines the pulse duration 14, producing pulses 15 and 16. Pulse 16 determines the polarization time of the piezoplate and locks the input of the amplifier 4 through the source 9 at this time, while the signal on indicator 5 does not arrive. The pulse 15 through the gate pulse generator 7 allows the pulse 17 to be output, the period of which is longer than the pulse period 11. As a result, the gate pulse 17 is displaced relative to the start of the sweep, indicator 5 in each subsequent period of the probe pulse 13 to the jn part of this period when the leading edge of the pulse 16 is rising affecting the sensitivity of the transducer. The moving impulse 17 at layer-by-layer monitoring provides information on the position of the defect (depth). ;

Thus, the described flaw detector allows the amplitude of the received echo signal to be adjusted depending on the depth of the defect by polarizing the transducer with the leading edge of the saw.

Claims (2)

1. USSR author's certificate number 451919, cl. G 01N 29/04. 2. The copyright certificate of application number 2540292, cl. G 01N 29/04, 1977 (prototype). 1L one. / 2 / j 17 PP El P