SU991283A1 - Electromagnetic checking device - Google Patents

Description

(FOR) DEVICE FOR ELECTROMAGNETIC CONTROL

The invention relates to non-destructive testing and can be used to measure the parameters of electroplating objects.

It is known that an electromagnetic control device comprising a series-connected generator, an electromagnetic converter included in an oscillating circuit, an amplitude detector and an indicator GO.

A disadvantage of the known device is the low reliability of the control, which is associated with the need to measure amplitudes with an accuracy comparable to measurement errors for possible variations in the frequency of the generator.

The device for electromagnetic control, which contains two measuring channels connected to it, consisting of a series-connected electromagnetic converter and an amplitude detector, is the closest in technical essence to the invention; a comparator connected to the outputs of the measuring channels, and a sequence. memory elements and L2J indicator.

However, this device does not allow control of non-ferromagnetic objects, since in the latter case, the equality of the compared amplitudes for any frequency is impossible.

The purpose of the invention is to provide control of non-ferromagnetic objects.

Claims (2)

The goal is achieved by the fact that a device for electromagnetic control, containing a sweeping frequency generator, two measuring channels connected to it, consisting of a series-connected electromagnetic converter and an amplitude detector, a JI com- pator connected to the outputs of the measuring channels, and connected in series. the memory element and the indicator are provided with a third measuring channel connected in series, identical to said input and connected to the sweeping frequency generator, a second comparator connected by another input to the output of the second measuring channel, and two differentiating chains connected between the outputs of the corresponding comparators and the inputs of the memory element ti, made in the form of a trigger, and electromagnetic transducers are included in the resonant circuits. FIG. 1 shows the structure of an electromagnetic control device; in fig. 2 — amplitude – frequency dependences of circuits with electromagnetic converters. The device consists of a oscillating frequency generator, - included in the resonant circuits of the measuring electromagnetic transducer 2 and compensation electromagnetic transducers 3 and i connected by inputs to the output of the generator, amplitude detectors connected by inputs to the outputs of electromagnetic transducers 2, 3 and k, respectively, and forming three measuring channels with them, comparators 8 and 9 connected by the first inputs with the output of the amplitude detector 6, and the second with the outputs of the amplitude detectors 5 and corresponding differentiating chains 10 and 11 and a memory element, made in the form of a trigger 12, connected by its inputs to the outputs of the comparators 8 and E via differentiating chains 10 and 11, respectively, and connected to the output with an indicator 13. The device for electromagnetic control works as follows: Electromagnetic transducer 2 is placed over a controlled product, the first compensating electromagnetic transducer 3 is placed in the dielectric space, and the second compensating electromagnet The inverter 4 is above the model product. The transducers included in the respective resonant circuits supply alternating current from the oscillating frequency generator 1 with alternating current and change its frequency. In this case, the voltage amplitudes at the output of the electromagnetic transducers 2, 3 and 4 vary in accordance with the curves (Fig. 2). In the process of measuring 99. . .. There are two frequencies (Fig. 2), the moments of equality of amplitudes at frequencies f (f and fjj-. The amplitudes of the voltages at the outputs of electromagnetic transducers 2 and 3 are compared using amplitude detectors 5 and 6 and comparator 8, similarly to amplitudes the outputs of electromagnetic transducers 3 and are compared using amplitude detectors 6 and 7 and comparator 9. at the moment of equality, the signal from the output of the corresponding comparator is formed by a differentiating string 10 or 11 and is fed to one of the trigger trigger 12, which is achieved by fixing Equality of time. The time interval between two moments of equality corresponds to the pulse duration at the trigger output 12. Measured by the indicator. 13 The time interval between two moments of p-equity of the compared amplitudes is determined by the parameters of the product under test. The device for ferromagnetic control, based on the described principle, allows to control non-ferromagnetic products with higher accuracy, as it has a high sensitivity and noise immunity. Claims An electromagnetic control device comprising a frequency oscillator, two measuring channels connected to it, consisting of a series-connected electromagnetic converter and an amplitude detector, a comparator connected to the outputs of the measurement channels, and a series-connected memory element and indicator, that, in order to ensure the control of non-ferromagnetic objects, it is equipped with series-connected third measuring channels identical to denoted AND connected to the oscillating frequency generator, a second comparator connected by another input to the output of the second measuring channel, and two differentiating chains connected between the outputs of the respective comparators and the inputs of the memory element, made in the form of Trig 5991, 283 Hera, and electromagnetic converters are included in the resonant circuits. Sources of information taken into account at. expertise 1, Dorofeev A.L., Nikitin A.I., Rubin A.L. Induction thickness gauge. M., Energie, 1978, p. 6 2. USSR author's certificate 5 No. 665259, cl. G 01 N 27/90, 1979 (prototype).