SU800632A2 - Magnetoacoustic thickness gauge - Google Patents

Description

54) MAGNITO ACOUSTIC THICKNESS MEASURES

one

The invention relates to non-destructive ultrasonic testing and can be used to control the thickness as well as the physicochemical properties of the products.

On the main, omu av.sv. P627317 is known for a magnetoacoustic thickness gauge containing a synchronizer connected in series, a probe pulse generator, a transformer, an amplifier and a first trigger, a recorder, a pulse shaper connected between the output of the synchronizer and the generator input, B7 anti-trigger, the first input of which is connected to the output of the amplifier, and the output to the recorder input, and a differentiating chain connected between the second one in the second trigger and the output of the first trigger, the second input of which is connected to the second synchro output izatora G.

The disadvantage of the known thickness gauge is the inability to determine the physicochemical properties of the products.

The invention is an extension of the functionality.

This goal is achieved by the fact that the magnetoacoustic thickness gauge

provided with serially connected reference signal generator, whose input is connected to the synchronizer output, shaper of reference signals, delay circuit, AND circuit, third trigger and indicator, buffer stage connected between the differentiating circuit and the second trigger and connected to the input

0 of the third trigger, a generator of high-frequency pulses, the input of which is connected to the third output of the buffer stage, and a unit for forming reference pulses connected 5 between circuit I and the generator of high-frequency pulses.

The drawing shows the block diagram of the thickness gauge.

Magnetoacoustic Thickness Gauge

0 contains serially connected synchronizer 1, pulse shaper 2, probe pulse generator 3, transducer 4, amplifier 5, first trigger 6, second

5 whose input is connected to the second output of the synchronizer, differentiating the chain 7, the buffer stage 9 high-frequency pulses, the unit 10 forming the reference

& pulses and circuit 11. To the third

connected to the synchronizer output are series-connected generator 3.2 of reference signals, driver 13 reference signals and circuit 14 for the holder, the output of which is connected to the second input of circuit I.

A second trigger 15 is connected to the input of amplifier 5, the second input of which is connected to the first output of the buffer stage 8, the second output of which is connected to the first input of the third trigger 16. The second input of the third trigger 16 is connected to the output of the And 11 circuit, and the output 17 o The output of the second trigger 15 is connected to the input of the recorder 18.

The magnetoacoustic thickness gauge works in the following way.

From the output of the synchronizer 1, a pulse arrives at the input of the driver 2 pulses, then to the generator 3 probe pulses and then to the converter 4. From the converter 4, the signal reflected from the bottom is fed to the amplifier 5. From the output of the amplifier

The 5 signal is fed to the inputs of the bi-15 trigger. To the second input of the trigger

6 sends a signal from the second output of synchronizer 1; On trigger 6, a rectangular pulse is produced whose beginning is limited by a pulse from synchronizer 1, and the end is impulsed from the output of amplifier 5. From trigger output 6, a positive square pulse is fed to differentiating chain 7, where the back front of the pulse forms short negative impulse. From the differentiating chain 7, a short-term negative pulse is applied to the buffer cascade 8, and then to one input of the second flip-flop 15. The second input of the flip-flop 15 receives a signal from the amplifier 5. The flip-flop 15 generates a square pulse, the beginning of which is limited by the impulse from the differential 1 7, the end of the second subsequent reflected pulse. The duration of a rectangular pulse from the second trigger is proportional to the thickness of the item being measured. The trigger 15 is connected with the recorder 18 thickness. In this way, the thickness of the product is measured.

To fix the change in speed caused by changes in the physicochemical properties of the products, a pulse is sent from the third output of synchronizer 1 to a generator 12 of reference signals, which is a generator with a shock excitation circuit. With a pulse from synchronizer 1, this generator is started. The generator 12 of the reference signals generates damped oscillations with a constant frequency f. These oscillations are fed to the driver of the 13 reference signals. .With the output of this shaper pulses of happiness

repetitions f are fed to the input of delay circuit 14. From the output of the delay circuit 14, pulses are fed to one input of the circuit 11. At the same time, from one output of the buffer stage 8 pos), pulses are fed to the input of the generator 9 high-frequency pulses, which is a generator with a shock excitation circuit, on it damping oscillations with a constant frequency -E which must exceed the frequency {hundred, thousand and more times, this depends on the technical capabilities of the device. The higher the frequency;; i the more accurate the measurement. These damped oscillations are fed to the input of the sampling pulse generation unit 10. From the output of block 10, a pulse comb is output with a repetition rate of 2- It enters input 11 and 11, where the reference pulses from the delay circuit 14 also arrive. In the diagram, And one of the comb pulses coincides with the nearest reference pulse. From the output of the circuit AND 11, the pulses arrive at the second input of the third trigger 16, the first input of which receives a pulse from the buffer stage 8. The pulse coming from the buffer stage 8 to the third trigger 16 can be in any position, i.e. between any two adjacent reference pulses or coincide with one of them. If they coincide, then it is not possible to assess the relative increase or decrease in the speed of ultrasound. Therefore, a delay circuit 14 is provided in the device, with which it is possible to delay reference pulses from 0 to one period, so that the pulse coming from the buffer stage 8 to the third trigger 16 is strictly midway between two adjacent reference pulses. This corresponds to the position of the indicator hand in the middle of the scale. The reference pulses are like reference pulses, and the pulses from the pulse shaping unit 10 are reference pulses. Thus, a total change in the ultrasound velocity, insignificant in its magnitude, which is caused by the presence of residual and applied stresses by mechanical anisotropy, and a change in the physicochemical properties of materials, will be recorded.

Claims (1)

1. USSR author's certificate 627317, cl. G 01 B 17/02, 1977 (prototype).