SU1364867A1 - Ultrasonic echo-pulse thickness gauge - Google Patents

Abstract

The invention relates to instrumentation technology and can be used for automated ultrasonic monitoring of the thickness of products, including with rough and corroded surfaces. The purpose of the invention is to increase the reliability and performance of controlling the thickness of products by increasing the noise immunity from local violations of the input conditions and the spread of ultrasound into the product. The goal is achieved by the fact that the waiting multivibrator controlling the operation of the memory unit is connected to the output of the second echo sig the second input is with the output of the memory unit, which filters out false values of the product thickness measurements. 2 Il. | (L

Description

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The invention relates to instrumentation technology and can be used for automated ultrasonic monitoring of the thickness of products, including those with draft and corroded surfaces.

The purpose of the invention is to increase the reliability and performance of controlling the thickness of products by increasing the noise immunity from local disturbances of the input conditions and the distribution of ultrasound in the product.

FIG. 1 shows a functional diagram of an ultrasonic echo-pulse thickness gauge; Fig. 2 shows a discrete sequence of thickness codes in analog form, which explains the operation of the device (a - before filtering, b - after filtering).

The ultrasonic echo pulse thickness gauge contains synchronizer 1, generator 2, piezoelectric transducer 3 and preamplifier 4, amplifier-shaper 5 of the first echo signal and amplifier 6 of the second echo signal, connected to the output of the preamplifier 4, the second input of the amplifier-shaper 5 connected with synchronizer 1, driver 7 measuring pulses, two inputs connected respectively to the outputs of the amplifier-former 5 and amplifier 6, the third input Analog-to-digital converter (ADC) 8 connected to synchronizer 1, connected to the output of the imaging unit 7, a second input connected to the synchronizer 1, connected to the input c., output of the amplifier 6 standby multivibrator 9, RS-trigger 10, the first input of which connected to the output of the synchronizer 1, and the second to the output of the waiting multivibrator 9, driver 11 of the control pulses, connected to the output of the driver 7 of the measuring pulses, the circuit 12, the first and second inputs of which are connected respectively with the first output of the RS flip-flop 10 and the output of the driver 11 of control pulses, a memory block 13 connected by inputs to the outputs of the And 12 circuit and the A / D converter 8, a digital filter 14, the first input of which is connected to the second output of the RS flip-flop 10, and the second input - with block 13 memory 0

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ti, blocks 15 and 16 digital display and automatic alarm, the inputs of which are connected to the output of the digital filter 14. In addition, a fragment of the monitored product 17 is shown.

The thickness gauge works as follows.

The synchronizer 1 generates sync pulses that trigger the generator 2. The pulses of the generator 2 excite the piezoelectric transducer 3, which emits an ultrasonic pulse along the normal and front face of the controlled product 17 into the contact liquid layer. The ultrasonic pulse undergoes reflection from the front face and multiple reflections between the front face and the inner surface of the product, after which it is received by the piezoelectric transducer 3, it is converted into electrical echo pulses, which are amplified by preamplifier A and 5, and then by the former and 5 second echo pulses.

In the imaging unit 7, impulses are formed, the duration of which is proportional to the time delays of ultrasound in the product. These pulses are fed to the input of the ADC 8, in which the value of the measured thickness in a parallel digital code is formed with a predetermined measurement resolution relative to the time interval. The outputs of each of the bits of the ADC 8 are connected to the corresponding inputs of the memory block 13.

The rewriting of the results in the memory unit 13 is carried out by parallel transfer of the control pulses to its corresponding inputs. These pulses are generated by the control pulse shaper 11 from the trailing edge of the measuring pulse and are switched by circuit 12.

The second (bottom) echo impulse from the output of the amplifier 6 is fed to the input of the standby multivibrator 9. From the output of the standby multivibrator 9, a pulse of a duration slightly longer than the duration of the measuring pulse is fed to the second input of the RS flip-flop 10. At the first output of the latter, the potential of the logical 1, on the second - the logical O. The potential of the logical 1 is fed to the first input of the circuit 12,

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the second input of which is supplied from the output of the driver 11 of the control pulses. In this case, circuit 12 allows the code to be rewritten from the ADC 8 to memory block 13.

After the end of the pulse produced by the waiting multivibrator 9, the signals at the outputs of the RS flip-flop 10 are reversed, i.e. at the first output, a logical O will be set, preventing the AND 12 circuit from passing the control pulse to the memory block 13 At the second output of the RS flip-flop; 10 will set logical 1 ,. incoming on digital filter 14 and allowing it to accept the thickness code recorded in memory block 13. The RS-flip-flop 10 organizes the operation of the thickness gauge so that during receiving information by the digital filter 14 from memory block 13, the code cannot be overwritten from ADC 8 to memory block 13.

In case of local disturbance of the acoustic path of the thickness gauge in memory unit 13, the results of previous measurements are preserved. False thickness values, having the character of short bursts against the background of slowly changing true values of thickness codes (Fig. 2a), are filtered by digital filter 14.

True values of thickness (Fig. 26) from the output of the digital filter 14 are fed to the inputs of blocks 15 and 16 of the digital indication and automatic signaling.

The use of a thickness gauge allows for automated control of the thickness of products with rough or corroded surfaces.

Claims (1)

The invention of the Ultrasonic Zoom Pulse Thickness Gauge Containing Successively five 5 o Q five connected synchronizer, generator, piezoelectric transducer and preamplifier, amplifier-former of the first echo signal and amplifier of the second echosignal, inputs connected to the output of the preamplifier, another input of the amplifier -former connected to the synchronizer, driver of measuring pulses connected by two inputs respectively to the outputs of the amplifier - the former of the first echo signal and the second echo amplifier with the third input connected to the synchronizer, connected in Om to the output of the measuring pulse generator is an analog-to-digital converter (ADC), connected to the synchronizer by the second input, a control pulse driver connected to the output of the measuring pulse generator, an RSF trigger, the first input of which is connected to the synchronizer output, And circuit, two inputs of which are connected respectively with the output of the control pulse generator and the first output of the RS flip-flop, a memory block, two inputs of which are connected respectively with the outputs of the circuit I and AC , digital indication unit, automatic signaling unit, characterized in that, in order to increase the reliability and performance of thickness monitoring of products, it is equipped with a digital filter, the first input connected to the second output of the RS flip-flop, the second input to the output of the memory unit, output connected with the inputs of the digital display unit and the automatic alarm unit, and the input of the waiting multivibrator is connected to the output of the second echo amplifier, and the output is connected to the second input of the RS flip-flop.