SU989454A1 - Pulse eddy-current thickness meter - Google Patents

Description

(PULSE VORTEX) THICKNESS MEASURES

one

The invention relates to non-destructive testing and can be used to measure the thickness of electrically conductive materials, mainly foils, during its production.

Known pulsed eddy current gauge containing serially connected pulse generator, measuring and compensating electromagnetic converters, amplifier, peak detector and indicator 1 1.

The disadvantage of this thickness gauge is the low reliability of the control, which is associated with the influence of external magnetic fields on the results of the control.

The closest to the invention in its technical essence is a pulsed eddy current thickness gauge containing a series-connected pulse generator, a buffer amplifier, a screen electromagnetic

a converter, an amplitude discriminator, a comparison unit, connected by a second output with a pulse generator, and a dial indicator 2.

However, this thickness gauge does not have the necessary reliability of control, which is associated with the compensation of the non-informative component of the signal after its conversion to analog form, and consequently, with the low stability of the thickness gauge.

ten

The purpose of the invention is to increase the reliability of the control.

Claims (2)

The goal is achieved by the fact that a pulsed eddy current measure, containing a series-connected pulse generator, a buffer amplifier, an on-screen electromagnetic converter, an amplitude amplifier, a discriminator and a comparison unit, connected by a second input to the pulse generator output, is connected in series with a modulator, first counter, a decoder, a zero setting switch, a trigger with a key and a sweeper, a pulse generator in the filling connected to the modulator; the second inputs of the latter and the trigger are connected to the output of the comparator unit, the fault inputs of the counters are connected to the output of the pulse generator, and the control input of the key is connected to the output of the modulator. The drawing shows a structural scheme of a pulsed eddy current gauge. A pulsed eddy current measuring device consists of a series-connected pulse generator 1, a buffer amplifier 2, an on-screen electromagnetic converter 3, an amplitude discriminator A, a comparison unit 5, a modulator 6, a first counter 7, a decoder 8, a switch 9. Zero settings, a trigger 10 key 11 and the second counter 12 and the filling pulse generator 13 connected to the second input of the modulator, 6, the control input of the switch 11 is connected to the output of the modulator 6, the fault inputs of the counters 7 and 12 and the second input of the block 5 They are connected to the output of the pulse generator 1, and the second input of the trigger TO is connected to the output of the unit 5 of comparison. The pulse eddy current thickness gauge works as follows. The pulse generator 1 through the buffer amplifier 2 is loaded onto the exciting winding of a screen-type electromagnetic converter 3, from the measuring winding of which the signal through the amplitude discriminator is replicated to block 5 of the comparison. The duration of the differential pulse generated in block 5 comparison, in addition to the information on the thickness of the object being monitored, contains a certain constant component, the value of which depends on the electrical parameters and the design of the screen electromagnetic converter 3 as well as on the setting of the thickness gauge as a whole. Next, the differential pulse is modulated by j modulator 6 by pulses from the generator 13 of the filling pulses and fed to the input of the first counter 7, Decoder B- converts the parallel binary-decimal code to decimal. The trigger 10 at the time of the start of the differential impulse goes into the excited state and locks the key 1.1. The trigger 10 is reset to the initial state by a pulse of the decoder 8, the number of which from the start of the comb of the filling pulses is determined by the position of the zero setting switch 9. After resetting the trigger 10, the key 11 is unlocked and passes the remaining comb pulses to the input of the second counter 12. Thus, at the output of the key 11, a sequence of pulses is formed, carrying information only about the thickness of the material under test, and the constant component 9 is set zero The second counter 12 converts a pulse comb into a standard code for communicating with external devices and a digital computer. The eddy current pulse thickness gauge possesses enhanced control reliability by eliminating the influence of external magnetic fields on the control results due to pulsed signal processing by modulating it at the output of the analog block and compensating the uninformative component of the signal in digital form. Claims of the Impulse Eddy Current Thickness Gauge containing a series-connected pulse generator, a buffer amplifier, an on-screen electromagnetic converter, an amplitude discriminator minator and a comparator unit connected to the second input with the output of the pulse generator, which is designed to ensure reliability of the control sequentially connected module spill, first counter, decoder, switch setting zero, trigger, key and second meter m, pulse generator filled and Con chennym to the modulator, the second inputs of the modulator and the trigger input connected to the comparison unit, blowdown estimators inputs connected to the output of the pulse generator and control 5989 5 | the key input is connected to the output of the mod- 1 1. USSR Certificate of Authorization ®RZ.N20077, cl. G 01 B 7/02, 1965. . 2. Certificate of CCCJf Sources of information according to the application (G 2702090 / 25-28, taken into account during the examination of 5 Cl. G 01 M 27/90, 1978 (prototype).