SU1693525A1 - Multichannel eddy current flow detector - Google Patents

Description

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(21) 4701269/28

(22) 06.06.89

(46) 11/23/91. Bul №43

(71) Moscow Aviation Technological Institute. KE Tsiolkovsky and Research Institute of Technology

(72) A.A. Grebnev, A.V. Uvarov, Yu.N.Naumov and V.N. Babkin (53) 620.179.14 (088.8)

(56) USSR inventor's certificate No. 726476, class, G 01 N 27/90, 1980.

 Author's certificate of the USSR No. 828059, cl. G 01 N 27/90, 1981.

(54) MULTI-CHANNEL VORTEX-DEFECTIVE DEFECTIC

(57) The invention relates to non-destructive testing of materials and products and can be used for defectoscopy of conductive objects. The aim of the invention is to increase the reliability of control by blocking the measuring circuit for the duration of the transients. The parameters of the monitored product are determined by n eddy current converters 2, which set the frequency n of controlled oscillators 1. Since the distributor of 4 pulses sequentially controls each controlled oscillator, for the time of setting its frequency a pulse from the clock generator 3 through the block 5 of the delay blocks the measurement process using the AND 6 scheme, which allows only reliable results to be displayed. 1 il.

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The invention relates to non-destructive testing of materials of products and can be used for the inspection of conductive objects.

The aim of the invention is to increase the reliability of control due to blocking of the measuring circuit for the duration of transients.

The drawing shows a block diagram of the device.

The device contains n controllable autogenerators 1.1 - 1.p and p eddy current transducers 2.1 - 2.p, respectively, included in the oscillatory circuits of controllable autogenerators 1.1 - 1. p.

The device also contains series-connected clock generator 3 and a 4-pulse distributor, the outputs of which are connected to the corresponding control inputs of controlled auto-generators 1.1-1.p, the delayed block 5 connected in series to the output of clock generator 3, circuit b and block 7 information processing, and the OR 8 circuit, connected between the outputs of the controlled oscillators 1.1 - 1.p and the second input of the AND 6 circuit.

The device works as follows.

The distributor of 4 pulses, controlled by the clock generator 3, alternately supplies the enabling signals to the controlled oscillators 1.1 - 1.p. The duration of the enabling signals is, for example, 1 ... 2 ms. At the time of the arrival of the enabling signal, the corresponding controlled oscillator is turned on and starts to operate in the auto-oscillatory mode. However, some time passes (for example,

+10 ... 30 µs, depending on the constant boom of its oscillating circuit), while the controlled oscillator 1 is set to a stable mode of operation and its frequency becomes constant. At this time, the output of the circuit OR 8 should be disconnected from the information processing unit 7. This blocking is carried out by the AND 6 circuit. The pulses necessary for this, synchronous with the leading edges of the output signals of the 4 pulse distributor, are produced by a delay unit 5. The synchronization of the operation of the entire device is carried out by the clock generator 3, the pulse period of which determines the time of operation of each controlled oscillator 1.

Claims (1)

Invention Formula Multichannel eddy current flaw detector containing p controlled autogenerators and p eddy current transducers included in the corresponding oscillatory circuits of controlled autogenerators, series-connected clock generator and pulse distributor, whose outputs are connected to control inputs of controlled autogenerators, IL-VI circuit connected to outputs of controlled auto-generators, a delay unit connected to the output of the clock generator, and an information processing unit, characterized in that to increase the reliability of the control, it is equipped with an AND circuit connected between the outputs of the OR circuit and the delay unit and the input of the information processing unit, and the delay time exceeds the time for setting the frequency of the autogenerators.