SU845077A1 - Device for non-destructive inspection of electroconductive articles - Google Patents

Description

(54) DEVICE FOR NON-DESTRUCTIVE TESTING OF ELECTRICAL WIRES

one

The invention relates to non-destructive methods for eddy current testing and measurement of products, and can be used in the testing and measurement of their geometrical and physical parameters in the metallurgical, engineering and other industries.

A device is known for measuring the physical parameters of the products, comprising a generator, an eddy current transducer made in the form of an inductance coil of a resonant generator circuit, and an indicator. To offset the effect of the gap, the resonant circuit of the generator is slightly frustrated so that changes in inductance and active resistance caused by an increase in the gap compensate each other 1.

The disadvantage of the device is a small range of detuning from the size of the gap, equal to 100-150 microns.

The closest technical solution to the invention is a device for non-destructive testing of electrically conductive products containing, in series, its generator, eddy current transducer, voltage compensation unit, amplifier, phase detector and indicator, as well as a reference channel connected between the output of the converter and the reference input of the detector 2 .

A disadvantage of this device is the small tuning range and the effect of the interfering parameter, for example, the gap, on the measurement accuracy.

The aim of the invention is to expand the tuning range and eliminate the influence of the mixer, its parameter on the measurement accuracy.

This goal is achieved by the fact that the device is additionally equipped with an amplitude-phase regulator connected between the generator output and the other input of the reference channel.

FIG. 1 shows a block diagram of the proposed device; in fig. 2 - hodographs of the insertion impedance of the converter for the device without amplitude-phase regulator (prototype); in fig. 3 - the same

20 for a device with amPlit-phase regulator.

Claims (2)

The device (Fig. 1) contains a series-connected generator I, a eddy current and differential converter 2, a voltage compensation unit 3, an amplifier 4, a phase detector 5, a 6 II indicator, a reference channel 7 connected between the output of the converter 2 and the reference input of the detector 5, as well as the amplitude-phase controller 8 connected between the output of the generator 1 and another input of the channel 7. The device operates as follows. The voltage from generator 1 is fed to converter 2. The signal (vectors ОВ, ОА, ОВ ОБ in Fig. 2) of converter is fed to block 3 and channel 7. Block 3 compensates for the initial voltage of converter 2, and amplifier 4 amplifies the signal of converter 2, which enters the detector 5; Channel 7 serves to change the phase of the reference voltage (NN, MIT. d.). The attached hodographs illustrate the measurement of the wall thickness of a non-magnetic metal pipe at various gap values. FIG. Figures 2 and 3 indicate the insertion resistance of the transducer 2 depending on the change in the thickness of the material being measured (line CAB, SAVI, e) and the gap (line AAO; BBO, etc.). The vectors AB and AC characterize the change in the insertion resistance as the material thickness changes, the vector AA — as the gap changes, and the vectors AB and AB change as the thickness and gap change. The vectors OV, AO, OV, OV correspond to the output voltage of the transducer 2 at different thicknesses of the material and different values of the gap. FIG. 2 that the projection (ОВ, Ввит.д of the voltage vector of the signal to the reference voltage will change when the interfering parameter (gap) is changed. The error will be detected in the output signal of the detector 5 and will fall on the indicator 6 in the form of the measured thickness Material. When applying to another input of channel 7, the voltage of generator 1 through regulator 8 (vector 00), changing the magnitude and phase of vector 00, you can achieve such a rotation of the phase of the reference voltage (Fig. 3), at which the projection of the signal voltage vector the reference voltage will be almost constant (DB, O B, etc.) with the same changes in the gap size (AA, BB). From the foregoing it can be seen that a change in the gap size in the claimed device has a much smaller effect on the measured parameter than in the known one. The introduction of an amplitude-phase regulator allows you to expand the range of tuning and eliminate the effect of the gap on the measurement accuracy.A invention The device for non-destructive testing of electrically conductive products, containing a series-connected generator, eddy current transducer, voltage compensation unit Either the phase detector and the indicator, as well as the reference channel connected between the output of the converter and the reference input of the detector, characterized in that, in order to expand the tuning range and eliminate the influence of the interfering parameter on the measurement accuracy, it is equipped with an amplitude-phase controller included between the output of the generator and the other input of the SUPPORT channel. Sources of information taken into account in the examination 1. A. Dorofeev A. A. Electroinductive (induction) defectoscopy. M., “Mechanical Engineering, 1967, p. 92 2. USSR author's certificate number 458702, cl. G 01 B 7/06, 1972 (prototype). 0y.f