SU1430875A2 - Ultrasonic flaw detector - Google Patents

Abstract

The invention relates to non-destructive ultrasound testing. The aim of the invention is to increase the productivity and reliability of control due to the formation of probing and pulses of a given amplitude. In the device, a capacitor is charged through a chain containing a matching circuit, a charging key, a voltage divider, a threshold device, BEFORE the voltage measured at the second input of the threshold device, and the subsequent discharge of the capacitor through an oscillating circuit containing the transducer . 2 Il. from 16

Description

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The invention relates to non-resolving ultrasonic methods and is an improvement of the known device according to the authors. St. No. 608091.

The purpose of the additional invention is to improve the performance and reliability of the control due to the formation of probing pulses of a given amplitude.

FIG. 1 shows a block diagram of an ultrasonic flaw detector; in fig. 2 - time diagrams that show his work.

The ultrasonic flaw detector contains a synchronizer 1, a receiving transducer 2 connected in series, an amplifier 3 and a recorder 4, a forma- tor 5 pulses, an output connected to the second input of the registrar 4, an expander 6 pulses, an input connected to the synchronizer output and an output to the input driver 5, the bit switch 7, the input connected to the output of the driver 5, the charging circuit 8, the output connected to the second input of the bit switch 7, the charge circuit 8 contains connected on a charge switch 9, a capacitor .10 and piezoelement 11, inductance 12, connected in parallel to piezoelectric element 11. A matching circuit 13 is connected between the input of the charging switch 9 and the output of the pulse expander 6, and the output of the charging switch 9 is connected to the input of the voltage divider 1.4 by the output connected to the first input a threshold device 15 whose output is connected to the second input of the matching circuit 13. A digital-to-analog converter (CDL) output 16 is connected to the second input of the threshold device 15.

Ultrasonic flaw detector works as follows. I

Using the known digital switches S1I of known input-output devices (not shown), the input of the D / A converter 16 supplies information about the required amplitude of the excitation pulses of ultrasonic-based sounds (UTs).

After conversion to a D / A converter 16, a predetermined voltage level is applied to the second input of the threshold device 15 and then equal to the required amplitude of the ultrasonic excitation pulse (taking into account the scale m "Uo / and" max. Max D Determined voltage applied

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power source (+ E) and charge key parameters 9; This is the maximum permissible input voltage of the threshold device 15. At the same time, the output of the threshold device 15 generates a signal 1, which is fed to one of the inputs of the matching circuit 13.

The synchronizer 1 generates the clock pulses (Fig. 2a) and starts the expander 6, which generates pulses with a duration of € 3 (Fig. 26), fed to the other input of the circuit 13 coincident. Thus, at the output of the matching circuit 13 synchronously with the clock pulses, pulses of duration C appear, sufficient to charge the capacitor 10 through the charging switch 9 of the charging circuit 8. The charging switch 9 opens, and the charge of the capacitor 10 starts. Circuits: power supply + E, charge switch 9, capacitor 10, piezoelement 11 with inductance parallel to it 12, ground.

When the voltage on the capacitor 10 reaches a value equal to mUndf at the output of the voltage divider 14 with a division factor equal to m, and the first input of the threshold device 15 is set to the same as at the second input of the threshold device 15, the threshold device 15, and an O signal appears at its output. This signal, fed to one of the inputs of the matching circuit 13, leads to its switching and locking of the charging key 9. Thus, the process of charging the capacitor 10 through the charging circuit 9 from the sourceItani E is stopped and it is maintained substantially constant voltage equal mVoof (FIG. 2c).

At the end of the pulse Dj (Fig. 26), the expander 6, the former 5, generates the falling edge of the expander pulse, and this pulse (Fig. 2d) starts the bit 7 and the recorder 1. At the same time, the discharge of the capacitor 10 along the circuit load (piezoelement 11 with inductance 12), capacitor 10, bit 7, ground. At the same time, at the indicated load there is a pulse (Fig. 2d), the amplitude of which corresponds to a predetermined level of the voltage of the excitation pulse mUnop

The recorder 4 serves to indicate pulses from the receiving transducer 2 through the amplifier 3,

The flaw detector allows you to quickly install, without changing the characteristics of the charging key, without resorting to a complex and time-consuming selection of circuit elements, the amplitude of the excitation pulses necessary to achieve the optimum operating mode of the converter. In addition, the set amplitude level does not depend on the voltage fluctuations of the charge circuit power source. Thus, productivity is improved and the quality and reliability of the control is ensured.

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Claims (1)

Invention Formula Ultrasonic flaw detector according to ed. St. No. 608091, distinguished by the fact that, in order to improve the performance and reliability of the control, it is equipped with a coincidence circuit, the first input connected to the expander output, and the output to the input of the charging circuit, voltage divider, the input connected to the output of the charging circuit, the threshold device, the first input connected to the output of the voltage divider, and the output to the second input of the matching circuit, and a digital-to-analog converter, the output connected to the second input of the threshold device. 13 6 one 75 / V fieL J6 aa X ffff / AT  71 i 71 I if5.5