SU1322136A1 - Device for eddy-current checking - Google Patents

Abstract

This invention relates to the field of non-destructive testing. The aim of the invention is to increase the accuracy of control due to the detuning from the instability of the amplitude of the reference voltage. The signal from the master oscillator 1 using an eddy current transducer 3 excites eddy currents in a controlled product. The information signal about the quality of the product goes to the key elements 6, 7, both directly and through the inverter 5. At the same time, the reference signal from the master oscillator 1 with a phase shift of and / 2 is supplied through the comparators 12, 13 to the multiplexers 15 and 17, where it switches reference oscillator frequency 18. The received signals control key elements 6 and 7, switching the direct and inverse signals to. the adder 8. After the selection of the information component of the selective amplifier 9, the signal magnitude is recorded by the indicator 11. 1 Cp f-ly, 1 silt .. And (L with

Description

The invention relates to non-destructive testing by the method of eddy currents and can be used in determining defects in metal products.

The purpose of the invention is to increase the accuracy of control by adjusting the amplitude of the reference voltage from instability.

 The drawing shows a block diagram of a device for eddy current testing.

The device contains power amplifier 2 connected in series to master oscillator 1, eddy current converter 3, preamplifier 4, inverter 5, two key elements 6 and 7, the second inputs of which are connected to the output of preamplifier 4, adder 8, electoral amplifier 9, phase detector 10 and indicator 11.

The device also contains two comparators 12 and 13 connected to the outputs of the master oscillator 1, connected in series the HE 14 and multiplexer.15, the second input of which is combined with the input of the HE 14 and connected to the comparator 13, and the output connected to the control input of the key element 7 connected in series with an HE 16 and multiplexer 17, the second input of which is combined with the input of the HE 16 and connected to the output of the comparator 12, the output of the multiplexer 17 is connected to the control input of the key element b, and the connected serial a reference oscillator 18 which outputs are connected to multiplexers 15 and 17 and phase shifter 19, whose output is connected to the phase detector 40,

The device works as follows.

From the quadrature outputs of the master oscillator 1, the voltages shifted by 7G / 2 are fed to the inputs of the comparators 12 and 13. Pass through the circuits NOT 14 and 16 and the multiplex 15 and 17 signals arrive at the control inputs of the key elements 6 and 7, successively switching their inputs to the input of the adder 8. At the same time, the signal from the master oscillator 1 is amplified by the power amplifier 2 and is fed to the eddy-current converter 3. The information signal

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The quality of the product (not shown) is amplified by the preamplifier 4 and is fed to the information inputs of key elements 6 and 7, both directly and through the inverter 5. In the adder 8, the direct and inverse signals are summed and the received signal is fed to the selective amplifier 9, where spectral components are selected; x signal. The signal then goes to the phase detector 10 and is registered by the indicator 11. The selection of the required phase shift of the control voltage of the phase detector 10 is made by the phase shifter 19. I The Formula was invented and.

1. A device for eddy current testing comprising a series-connected oscillator, a power amplifier, an eddy current transducer and a preamplifier, a series-connected selective amplifier, and a phase detector. an indicator and a reference generator and a phase shifter connected in series to the reference input of a phase detector, in particular, in order to increase control accuracy, it is equipped with an inverter connected in series to the preamplifier output, two key elements whose second inputs connected to the output of the preamplifier, and an adder, the output of which is connected to the input of the selective amplifier, are connected in series with the first charger connected to the A main generator, a NOT circuit and a multiplexer, the second input of which is connected to the output of the first comparator, the control input is connected to the output of the reference generator, and the output is connected to the control input of the first key element and connected in series by a second comparator connected to the master oscillator, the second NOT and the second multiplexer, the second input of which is connected to the output of the second comparator, the control input is connected to the output of the reference oscillator, the output of the second multiplexer is connected to the control input of the second key element.

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and the master and reference oscillators of a low-pass filter with a frequency are filled with quadrature and outputs. a slice equal to the frequency of the reference gene- 2. The device according to claim 1, of the slider, with a ratio of operating frequencies, is that the driver and reference oscillator amplifier is designed as “more than one.

Claims (2)

The formula is invented and. I 1. A device for eddy current control, containing a serially connected master oscillator, a power amplifier, an eddy current transducer and a preliminary amplifier connected in series with a selective amplifier, a phase detector and. an indicator and a reference oscillator and a phase shifter connected in series to the reference input of the phase detector, characterized in that, in order to improve the control accuracy, it is equipped with two key elements connected in series to the inverter connected to the output of the preamplifier, the second inputs of which are connected with the output of the pre-amplifier, and an adder, the output of which is connected to the input of the selective amplifier, connected in series by the first comparator connected to the master to the generator, the NOT circuit and the multiplexer, the second input of which is connected to the output of the first comparator, the control input is connected to the output of the reference generator, and the output is connected to the control input of the first key tori 12 and 13. Having passed through the circuits NOT 14 and 16 and the multiplexers 15 and 17, the signals are fed to the control inputs of the key elements 6 and 7, sequentially switching their inputs to the input of the adder 8. At the same time, the signal from the master oscillator 1 is amplified by a power amplifier 2 and fed to the eddy current transducer 3. Information signal element a, and connected in series by a second comparator connected to a master oscillator, a second NOT circuit and a second multiplexer, the second input of which is connected to the output of the second comparator, the control input is connected to the output of the reference generator, the output of the second multiplexer is connected to the control input of the second key element, and the master and reference generators are made with quadrature outputs. 2. The device according to claim 1, characterized in that the selective amplifier is made in the form of a low-pass filter with a cutoff frequency equal to the frequency of the reference oscillator, with a ratio of the operating frequencies of the master and reference oscillator 5 greater than one.