SU1538111A1 - Eddy-current flaw detector - Google Patents

Abstract

The invention relates to non-destructive testing and can be used for the inspection of electrically conductive objects. An increase in the reliability of the control is achieved by reducing the likelihood of missing defects in the tuning of the oscillator, caused by a change in the control conditions. The signal from the threshold device 4 transfers the one-shot 14 to the active mode, generating a pulse and opening key 9. The signal from the amplitude detector 3 is fed to the stored memory 10 and is stored in it. If the voltage level of the autogenerator 1 changes under the influence of variation in the monitoring conditions, a signal appears at the output of comparator 11 that controls key 6, which leads to reconfiguration of the flaw detector. During the retuning, the retuning mode indicator 13 is turned on. 1 il.

Description

one

(21) 4428412 / 25-28

(22) 05.23.88

(46) 01/23/90. Bul № 3 (71) State Research Institute of Civil Aviation

{72) Yu.G. Kazamanov, R.I. Likhachev and N.S.Stemasov (.53) 620.179.14 (088.8)

(56) USSR Copyright Certificate No. 1071956, cl. G 01 N 27/90, 1982.

USSR author's certificate 1105802, cl. G 01 N 27/90, 1981. (54) DIXED DEFECTOSCOPE

(57) The invention relates to non-destructive testing and can be used for flaw detection of electrically conductive objects. Improving the reliability of control is achieved

by reducing the likelihood of missing defects during detuning of the autogenerator caused by a change in control conditions. The signal from the threshold device 4 translates the one-shot 14 into the active mode, generating a pulse and opening key 9. The signal from the amplitude detector 3 is fed to the stored memory 10 and stored in it. If the voltage amplitude of the autogenerator 1 changes under the influence of variation in the monitoring conditions, a signal appears at the output of comparator 11 that controls key 6, which leads to reconfiguration of the flaw detector. During the retuning, the retuning mode indicator 13 is turned on. 1 il.

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The invention relates to non-destructive testing and can be used for the inspection of electrically conductive objects,

The purpose of the invention is to increase the reliability of the control by reducing the likelihood of missing defects during detuning of the oscillator caused by a change in the conditions of the control.

The drawing shows a structural diagram of the eddy current flaw detector.

Eddy current flaw detector contains auto generator-1, eddy current transducer 2 connected to the oscillator circuit of auto generator 1, amplitude detector 3 connected in series, threshold device 4, controlled pulse generator 5, controlled keys 6 and sawtooth generator 7, connected to control output the input of the oscillator 1, the output of which is connected to the input of the amplitude detector 3, the defect indicator 8 connected to the output of the threshold device 4, the switch 9 connected in series, controlled by my storage device 10, comparator 1J, logic circuit OR 12, and indicator 13 for changeover mode, one-shot 14, connected by input to output of threshold device 4 and output to second inputs of key 9 and logic circuit OR 12, first input of key 9 and second comparator input 11 are connected to the output of the amplitude detector 3, and the second inputs of the controllable key 6 and the controllable storage device 10 are connected to the output of the comparator 11.

Eddy current flaw detector works as follows.

When the supply voltage is switched on, the autogenerator 1 is in a passive mode, since the controllable voltage taken from the sawtooth generator 7 has a minimum value. At the same time, the controlled pulse generator 5 is in active mode. When the operator acts on the controlled key 6, a sequence of pulses produced by the generator 5 of pulses is fed to the former 7 of the sawtooth voltage, gradually increasing its output voltage. Managed Entry

Oscillator 1, this voltage puts it in active mode. The high-frequency voltage produced by the auto-oscillator 1 is detected by an amplitude detector 3 and supplied to a threshold device 4, at the output of which a control pulse is formed, which translates the pulse generator 5 into a passive (standby) mode. This completes the setup process and the flaw detector is ready for operation.

Work in a mode of reconfiguration

occurs as follows.

The signal from the threshold device 4 puts into operation the one-shot 14 vibrator that generates a pulse of the selected duration, which includes the second switch 9 for a time equal to the pulse duration. In off, P, closed condition switch 9 passes the analog signal from detector 3 to

5, the storage device 10, the amplitude value of this signal is memorized by the device as being equal to its value at the moment the one-shot 9 goes into passive mode. The comparator 11, which is controlled by the storage device 10, makes a continuous comparison of the reference signal coming from the memory with the variable signal taken from the amplitude detector 3. If the amplitude of the high-frequency voltage produced by the auto-oscillator 1, due to changes in control conditions increases, for example, due to increased clearance

0 between the electromagnetic transducer 2 and the product being tested or an increase in the electrical conductivity of the material being monitored, a signal appears at the output of the comparator 11,

5 that controls the automatic activation of the key 6, which causes a repeated adjustment mode of the flaw detector, and resets the signal recorded in the memory to the previous value. At the same time, an indicator is turned on, signaling that a reconfiguration is taking place, and it is in the active state before the process of recording the new value of the signal value in the storage device 10. With this

5, the indicator 13 is connected to the comparator 11 through the logic circuit OR 12, one of the outputs of which receives a signal from the comparator 1 IA

0

five

5P381

and the second from the one-shot 14, which controls the recording process.

When a defect appears, the signal voltage at the output of the auto-oscillator 1 decreases sharply, which is fixed by 5 defect indicator 1 connected to the output of the threshold device 4.

Claims (1)

Invention Formula Eddy current flaw detector containing a eddy current transducer connected in series by an oscillator, the oscillating circuit of which includes an eddy current transducer, an amplitude detector, a threshold device, a controlled pulse generator, a controlled key, and a sawtooth voltage driver connected to the control input of the autogenerator, five 0 15 0 11 6 and the output of the threshold device is connected to the defect indicator, due to the fact that, with the control accuracy chain, it is equipped with a second key serially controlled by a storage device, a voltage comparator, a second input connected to the output of the amplitude detector, a logic circuit OR and a reset mode indicator and a one-shot connected to the output of the threshold device and output connected to the second inputs of the key and logic circuit OR the first input of the second key to connect ene yield amplitude detector; , and the second inputs of the controllable storage device and the first controllable key are connected to the output of the comparator.