SU1133544A1 - Device for ultrasonic material quality control - Google Patents

Abstract

1. A DEVICE FOR ULTRASOUND CONTROL OF MATERIAL QUALITY, containing a synchronizer connected in series, a probe pulse generator, emitting and receiving transducers, an amplifier and a time measuring unit connected by a second input to a synchronizer, characterized in that, p. The purpose of the control accuracy is that they are connected in series with the amplifier output by a peak detector, a comparator, a first trigger, a sawtooth generator, a first key connected by a second input to the output of the first trigger, and an integrator connected to the control input of the amplifier connected to the sawtooth generator voltage with a second trigger connected between the output of the amplifier and the second input of the comparator with a second key, connected by a second input with the output of the second trigger, and including nnym sinhronizato between the set and the second input of said first mp iggbra frequency divider, and a second output of the first flip-flop is connected to the second inputs of the peak detector, and time measuring unit. EH € H oo with sd

Description

2, the apparatus according to claim 1, characterized in that the amplifier is designed as an operational amplifier in an inverting switch, parallel to the inverting switch, a capacitor is connected, and connected in a negative feedback circuit

parallel to the resistor and the field-effect transistor connected by the source to the inverting input of the amplifier, the drain to the output of the latter, and the gate of the field-effect transistor intended to be connected to the integrator.

The invention relates to non-destructive testing methods and can be used for the inspection of rocks. A device for ultrasound quality control of materials is known, which contains a series-connected synchronizer, probe pulse generator, radiating and receiving transducers, amplifier, modulator, delay line, comparison circuit, time generator, selector and counter, reference frequency generator connected to the BTopbw inputs the modulator and the Selector, the synchronizer being connected to the second input of the time interval generator, and the modulator to the second input of the comparison circuit lj The disadvantage of this device -keeping is low, the accuracy of control associated with the lack of interference immunity. The closest to the invention of the technical nature is a device for ultrasonic testing of the quality of materials, comprising a synchronizer connected in series, a probe pulse generator, an emitting and receiving transducer, an amplifier and a time measuring unit connected by a second input to the synchronizer Sh. The known device is low control accuracy, due to the large attenuation of ultrasonic vibrations in the coarse-grained materials, as a result of which the level of the first The signal stage may be below the response threshold of the time measurement unit. The purpose of the invention is to improve the accuracy of control. The goal is achieved by the fact that a device for ultrasonic quality control of materials, comprising a synchronizer connected in series, a probe pulse generator, emitting and receiving transducers, an amplifier and a time measuring unit connected to the synchronizer with a second input, connected in series with the amplifier output with a peak detector, comparator, the first trigger generator sawtooth voltage, nefjBbiM key connected to the second input with the output of the first trigger, and integrat with a pitch connected to the control input of the amplifier connected to the pipoo voltage generator by a second trigger connected between the amplifier output and the second input of the comparator with a second key connected by a second input with the output of the second trigger and a frequency divider connected between the synchronizer and the second input of the first trigger, and the second output of the first trigger is connected to the second inputs of the peak detector and the time measurement unit. In this case, the amplifier is designed as an operational amplifier in an inverting switch, a capacitor is connected in parallel with the inverting input, a parallel resistor and a field-effect transistor connected to the inverting input of the amplifier are connected to the negative feedback circuit, the drain to the output of the latter, and the gate of the field-effect transistor designed to connect to the integrator. FIG. 1 shows a block diagram of the device; FIG. 2 is a circuit diagram of an amplifier; in FIG. 3. 3 - timing diagrams for the operation of the device. A device for ultrasonic quality control of materials contains a series-connected synchronizer 1, a generator of 2 probe pulses, an emitting transducer 3, a receiving transducer 4, an amplifier 5, a peak detector 6, a comparator 7, the first trigger 8, the generator 9 sawtooth voltage, the first key 10 and the integrator 11, connected to the control input of the amplifier 5, connected to the generator 9 of the sawtooth voltage, a second trigger 12, connected between the output of the amplifier 5 and the second input of the comparator 7 second key 13, The second input with the output of the second trigger 12 connected between the synchronizer 1 and the second input of the first trigger 8 is a frequency divider 14 and a time measuring unit connected by its inputs with the synchronizer 1, the amplifier 5, the second output of the first trigger I, the latter connected to the second input of the peak detector 6. Amplifier 5 is made in the form of an operational amplifier 16 (the correlation circuit in Fig. 2 is not shown), in parallel with the inverting input 17 of which is connected a capacitor 18, a parallel connected resistor is connected to the feedback circuit 19 and the field-effect transistor 20, the source 21 of which is connected to the inverting input of the amplifiers 16, the drain 22 - with the output of the forces 16, and the gate 23 is intended for connection to the integrator 11. The device operates as follows. The synchronizer t generates serial pulse pulses 24 that, from permeation, arrive at the generator 2 probe pulses, exciting the radiating transducer 3. The pulses of ultra sound vibrations are introduced into the controlled material, which has passed through the receiving transducer 4. At the same time as the synchronizer 1 starts, the generator 9 generates a sawtooth voltage 25, the period Tj of which is much longer than the period of the clock pulses 24. A linearly increasing voltage 25 through the public key 10 and the integrator 44 torus 11 goes to the control vhol amplifier 5. Under the action of the voltage 25, the internal resistance of the Kvz of the field-effect transistor 20 changes, thereby changing the resistance of its feedback core {nd (,. K ,, - Kdn / th "- Yv") and the complex input Resistance) of the operational amplifier 16, which has an inductive nature of VC (where эe 8 с s / Co, 1 Gyos / oF " KO is the gain of the voltage of the amplifier with open-loop feedback; UCD cut-off frequency of the amplitude characteristic of the amplifier. Thus, a change in voltage 25 at the control input of amplifier 5 leads to a change in the magnitude of the synthesizable base of operational amplifier 16 inductance. As a result, the amplitude-frequency characteristic of the receiving path (converter 4 connected to amplifier 5) is tuned, the maximum of which is shifted in frequency from l, j up to l12 c. The upper limit of the operating frequencies fg pp, within which the frequency response of the receiving path is possible, is determined by the type of operational amplifier used and, as shown by experimental studies, 0, frp.yc, where yj, is the upper limit frequency of the operational amplifier. So, for example, if the operational amplifier is complete on a 284UD1A, 1 MHz microcircuit, a g rpOllO kg1. At some instant of time t, voltage 25 at the control input of amplifier 5 reaches the value at which 2g) j takes on the value corresponding to the tuning of the receiving electroacoustic path to the optimum frequency lonT, t, e. the frequency at which the transmission coefficient of the entire electroacoustic train will be maximum. At this point in time, the signal 26 at the output of the amplifier 5 will have a maximum amplitude. With a further increase in the control voltage 25, the pulses 26 begin to kill. P1 pulses 26 from the output of amplifier 5 are fed to a peak detector 6, the voltage level 27 at the output of which is equal to the level of the maximum of the pulses 26, i.e. Peak detector 6 remembers the maximum level reached by the input signal. Voltage 27 arrives at the first input of the comparator 7. At time vg, the linear increase in voltage 25 ends and a second trigger 12 is thrown backwards (reverse FRONT). The second trigger 12 opens. The signal from trigger 12 opens the second key 13, and the pulses 26 from the output of amplifier 5 arrive to the second input of the comparator 7. The voltage 28 of the sawtooth voltage generator 9 starts to increase again to the time point t when the output of the amplifier 5 along the line L of the maximum pulse 26. At time ij, the signals 26 and 27 (respectively, on the second and first inputs ah comparator 7) are equal and the computer 7 outputs a pulse Rhatore tipping conductive first flip-flop 8. The output signal from the first flip-flop 8 closes the first switch 10 and the output provider 11 yimerpa voltage 29 is set at a constant value. The input to the control input of the amplifier 5, the voltage 29 provides such KQJ values. and Z gx) at which the signal at the output of the amplifier 5 is maximum. Simultaneously signal

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4 6, from the second output of the first trigger 8, zips the peak detector 6 and instructs the unit 15 to measure time at the beginning of the measurements. The latter measures the propagation time tp of the ultra sonic oscillations between the radiating transducer 3 and the receiving transducer 4. The magnitude of the tp allows determining the speed of propagation of ultrasonic vibrations in the controlled material, which correlates with its different quality characteristics, using a known measurement base. At time i, which is determined by frequency divider 14, the pulse from the output of synchronizer 1 arrives at the second input of the first trigger 8, transfers it to a new state, and all processes in the device are repeated from the beginning. The use of the invention makes it possible to increase the control accuracy by automatically adjusting the frequency, which ensures the maximum transmission coefficient of the electroacoustic path, which prevents the device from triggering due to interference or not on the first input of the received acoustic signal,

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Claims (2)

1. DEVICE FOR ULTRASONIC QUALITY CONTROL OF MATERIALS, comprising a synchronizer connected in series, a probe pulse generator, an emitting and receiving transducers, an amplifier and a time measuring unit connected to the second input with a synchronizer, characterized in that, in order to improve the accuracy of control, it equipped with a peak detector, a comparator, a first trigger, a sawtooth generator, a first key connected to a second input with an output the first trigger, and an integrator connected to the control input of the amplifier, connected to a sawtooth generator by a second trigger, connected between the output of the amplifier and the second input of the comparator by a second key connected by the second input to the output of the second trigger, and connected between the synchronizer and the second input of the first trigger divider frequency, and the second output of the first trigger is connected to the second inputs of the peak detector and time measuring unit. Fig t J „, .1133544> 2. The device according to π. 1, characterized in that the amplifier is designed as an operational amplifier in an inverting switch, a capacitor is connected in parallel with the inverting input, a resistor and a field effect transistor connected in parallel to the inverter | to the amplifying input of the amplifier, by drain to the output of the latter, and the gate of the field-effect transistor is intended for connection to an integrator