SU1323945A1 - Device for pulsed eddy-current check - Google Patents

Abstract

The invention relates to non-destructive testing and can be used to measure the electrophysical parameters of electrically conductive products. An increase in the control reliability is achieved by suppressing the variation of the gap between the eddy current transducer and the product under test without using a shake. The duration of the rectangular pulse emitted by the detector 6 is determined by the parameters of the product. With the variation of the gap, the amplitude at the output of the subtracting unit 4 changes, but the position of the nodal point, which determines the pulse duration at the output of the detector 6 connected to the indicator 9, remains practically unchanged. 2 Il.

Description

The invention relates to a non-destructive testing technique and can be used to measure the electrophysical parameters of electrically conductive products.

coal impulse of positive polarity (Fig. 2, plot 17), and from the second half-wave - impulse of negative polarity (Fig. 2, plot 18). Rectangular

The purpose of the invention is to increase the accessibility of the positive polarity of the control due to the suppression effect of the first detector 6 (Fig. 2, the epoch of the variation of the gap between the eddy current transducer and the surface of the emitter 19) match. With simultaneous input to the inputs of the circuit 7, the coincidence of a rectangular pulse of positive polarity

whether on the results of the control.

FIG. 1 is a block diagram of a pred10.

19) and is fed to the input of coincidence circuit 7. With simultaneous input to the inputs of the circuit 7, the coincidence of a rectangular pulse of positive polarity

From the detector 6 and the clock pulses from the generator 12 clock pulses, the output of the circuit 7 coincidence pulses appear (Fig. 2, plot 20), which are fed to the counter 8 pulses. Total collated device; in fig. 2 - voltage diagrams explaining the principle of operation of the device.

The device contains a series-connected pulse generator 1, a worker 2 and a compensation 3 eddy current counting pulses, recorded transducers, a subtraction unit 4, a pulse counter 8 pulse, depends on the duration of a rectangular pulse emitted by detector 6 (Fig. 2, plot 19) which, in turn, is determined by the value of the controlled parameter of the products - but also connected to the output of the generator. 20 electrical conductivity of the material. The subtractive unit 4 has two inputs, to a thick part, of an electrically conductive coating. Thus, the value of the controlled product parameter will be determined and the indicator 9 readings, the input of the skimmer, will be strictly identical and connected with the output of the counter 8 by it. In addition, the device contains pulses. The detector 10, whose input is connected to the detector 10 and is single with the output of the amplifier-limiter 5, the novibrator 11. The input of the detector 10 connects the negative pulse (Fig. 2).

plot 21) supplied to the one-shot 11. The output signal of the one-shot 11

counter 8 pulses. The second input of the circuit Q (Fig. 2, plot 22), which is fed to the input of the 7th coincidence, is connected to the output of the "Pulse counter 8 pulse," the last is reset. Increasing the gap reduces the amplitude of the signal at the output of the subtracting unit 4 (Fig. 2, plot 17), but practically does not change the strip 13), which are fed to the excitation of node A. Due to this, the coils of eddy current transform The pulse duration at the output of the first detector 6 (Fig. 2, plot 19), and, consequently, the indication of indicator 9 when the gap changes.

tel limiter 5, detector 6, coincidence circuit 7, pulse counter 8 and indicator 9. The exciter coils of transducers 2 and 3 are connected in series by measuring coils of working and compensating transducers 2 and 3, respectively. Both are dominated by the output of limiting amplifier 5, and the output one-shot 11 - to the input "Reset

RATOR 12 clock pulses.

The device works as follows.

The generator 1 generates rectangular voltage pulses (Fig. 2,

2 and 3, and cause a current in them (Fig. 2, plot 14). When the working transducer 2 is not installed on the object of control, induced in its measuring coil, the EMF (Fig. 2, plot 16) is 40 EMF, induced in the measuring coil of the compensation transducer 3 (Fig. 2 plot 15). At the outputs of the subtracting unit 4 (Fig. 2, plot 17), the amplifier-limiter 5 (Fig. 2 plot 18), the first detector 6 (Fig. 2, plot 19), coincidence circuit 7 (Fig. 2, plot 20), the second detector 10 (Fig. 2, plot 21) and the one-shot 11 (Fig. 2, plot 22) in this case, there are no signals.

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Claims (1)

Invention Formula A device for pulsed eddy current control, containing a pulse generator, a working and compensating eddy current transducers, the excitation coils of which are connected in series and connected to a pulse generator, a subtraction unit connected by the corresponding, their inputs to the measuring devices. on the surface of the product, the EMF on its measuring coil decreases (Fig. 2, Fig. 16). At the output of the subtracting unit 4, a signal appears (Fig. 2 plot 17), which is caused by eddy currents in the material of the test object. 55 pulses connected by the output from the indicator - This signal from the subtraction unit 4 by the subcontrol connected in series by the second A limiting amplifier 5 is formed by a detector and a single vibrator, which is connected from the first half-wave signal directly to the input “Reset pulse counter. , and an indicator, characterized in that, in order to increase the reliability of the control, but provided with a series-connected limiter, the first detector, a coincidence circuit, and a counter coal impulse of positive polarity (Fig. 2, plot 17), and from the second half-wave - impulse of negative polarity (Fig. 2, plot 18). Rectangular  a pulse of positive polarity is extracted by the first detector 6 (Fig. 2, a pulse of positive polarity is extracted by the first detector 6 (Fig. 2, 19) and is fed to the input of coincidence circuit 7. With simultaneous input to the inputs of the circuit 7, the coincidence of a rectangular pulse of positive polarity From the detector 6 and the clock pulses from the generator 12 clock pulses, the output of the circuit 7 coincidence pulses appear (Fig. 2, plot 20), which are fed to the counter 8 pulses. The total number of counting pulses recorded by the pulse counter 8 depends on the duration of the square pulse emitted by detector 6 (Fig. 2, plot 19), which, in turn, is determined by the value of the controlled parameter of the products, the electrical conductivity of the material. thick parts, electrically conductive coating. Thus, the value of the monitored product parameter will determine the indications of the indicator 9, whose input is associated with the output of the pulse counter 8. The detector 10, the input of which is connected to the output of the amplifier-limiter 5, emits a negative pulse (Fig. 2). 40 45 Invention Formula A device for pulsed eddy current control, containing a pulse generator, working and compensating eddy current transducers, excitation coils of which are connected in series and connected to a pulse generator, subtracting unit connected by corresponding, their inputs to measuring Q coils of eddy current transducers - 55 pulses connected by the output with an indicator connected in series by the second coils of eddy current pulses connected by an output with an indicator connected in series by a second , and an indicator, characterized in that, in order to increase the reliability of the control, but provided with a series-connected limiter, the first detector, a coincidence circuit, and a counter 1323945 34 as well as a clock pulse generator, the body is connected to the output of the subtracter by an interlocked output to the second input ka, and the input of the second detector to the output of the coincidence circuit, the input of the limiting amplifier-limiting amplifier. Fi2.g