SU1629754A1 - Ultrasonic non-contact thickness gauge - Google Patents

Abstract

The invention relates to non-destructive testing and can be used to automatically measure the size of various objects. The purpose of the invention is to improve the measurement accuracy by eliminating the systematic error that occurs when changing signal delays in an acoustic channel. The use in the thickness gauge of the measurement results correction unit allows, in the absence of a controlled product in the control zone, to measure the systematic error in the control process of the initial reading (zero), equal to the difference between the sum of the distances from the transmitting transducers to the receiving ones in the measuring channels and the distance from the transmitting transducer to receive it in the compensation channel, memorize it, and in the process of measuring the thickness of the monitored product add up with the measurement result or subtract from it depending on the sign of the error, which increases the accuracy of control when exposed to external factors. 5 hp f-ly, 3 ill. with

Description

The invention relates to non-destructive testing means and can be used to automatically measure the thickness of moving articles with a non-contact ultrasonic method.

The aim of the invention is to improve the measurement accuracy by eliminating the systematic error that occurs when changing signal delays in the measurement channels.

FIG. 1 shows a structural diagram of an ultrasonic contactless thickness gauge; in fig. 2 - functional diagram of the measuring channel; in fig. 3 is a functional block diagram of the correction of measurement results.

The ultrasonic contactless thickness gauge contains synchronizer 1, first 2 and second 3 measuring and compensating 4 channels, each made of electroacoustic connected generator of 5 probing pulses, transmitting transducer 6, receiving transducer 7 and forming amplifier 8, and measuring unit 9, made from the first 10, second 11 and third 12 converters, duration - code, counter 13 cycles, generator 14 counting pulses and series-connected adder 15, subtractor 16, a result counter 17, a register 18 and an indicator 19 results, and

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The measurement results correction unit 20, the first input of which is connected to the output of the adder 15, the output of the synchronizer 1 is connected to the inputs of the generator 5 probe pulses and to the first inputs of the first 5 10, second 11 and third 12 transducers duration - code, outputs of the shaping amps & 8 channels 2-4 are connected to the second inputs of the first 10, second 11, and third 12 transducers — 10 code — the second input of the measurement result correction unit 20 is connected to the second input of the sender 16 and to the output of the third transducer 12 validity is the code, the third input is to the third inputs of the first 10, 15 second 11 and third 12 transducers duration is the code and to the generator output 14 counting pulses, the fourth input to the output of subtractor 16, the fifth input is intended for mechanical communication with 20 controlled product, the sixth input is connected to the fourth inputs of the first 10, second 11 and third 13 converters, duration - the code and the output of the counter 13 cycles, the first output - to the fifth inputs 25 of the first 10, second 11 and third 12 converters, duration - the code, the second output one to input Record gistra 18, third output - to the input Record counter 17 results, fourth output - to the control input of the synchronizer 1, the fifth sixth and seventh outputs - to the inputs Reset, subtract and sum counter 17 results, respectively, the first and second inputs The adder 15 is connected to 35 outputs of the first 10 and second 12 converters, the duration is a code, and the output of the counter 13 cycles is connected to the output of the amplifier - shaper 8 and to the second input of the converter 12 of the compensation channel 4. 40

Also indicated are the controlled product 21 and the reflector 22 of the compensation channel 4,

The measurement result correction unit 20 is made of serially connected 45 error counter 23, parallel code to serial converter 24, and account reversal circuits 25, 1. 3 consecutively connected reset circuits 26 to O, and the first 50 OR-NOT element 27, whose output is the first output of the measurement results correction unit 20, from the series-connected sensor 28 of the presence of controlled devices, the IS-NE 55 29 element and the first multi-phase generator 30, of the second M-HE 3 element sequentially connected and the second multiphase generator 32, the second 33 and the third 34 elements OR NOT, the first inputs of which

combined and connected to the first output of the reset circuit 26 to O, the outputs are the second and fifth outputs of the measurement result correction unit 20, respectively, the second and third inputs of the account reversing circuit 25 are the second and first inputs of the measurement result correction unit 20, respectively, the fourth input connected to the input Reset error counter 23, to the second input of the first element OR NOT 27 and to the second output of the sensor 28 of the presence of the monitored product, the first and second outputs are the sixth and seventh output of the result correction block 20 Measurements, the first input of the second element AND-NOT 31 is connected to the third output of the sensor 28 having a monitored product, the second input is combined with the second input of the first AND-NE element 29 and is the sixth input of the measurement correction unit 20, the first output of the first multiphase generator 30 connected to the input Record counter

23 errors and the second input of the parallel code converter 24 to the serial one, the second output to the third input of the first element OR NOT 27, the first output of the second multiphase generator 32 is the third output of the measurement result correction unit 20 the second output connected to the third input of the converter

24 parallel code in serial, the third output - to the second input of the second element OR-NOT 33, the fourth output - to the second input of the third element OR-NOT 34 and the fourth input of the first element OR-NOT 27, the input of the sensor 28 having a controlled item It is the fifth input of the measurement results correction unit 20, the fourth output of the sensor 28 of the product being monitored is connected to the fifth input of the first element OR 27, the information input of the error counter 23 is even twist input of the measurement result correction unit 20, the fourth input of the parallel-to-serial code converter 24 —a third input of the measurement result correction unit 20, and the second output of the reset circuit 26 to zero — the fourth output of the measurement result correction unit 20,

The parallel code to serial converter 24 is made of a series-connected first trigger 35, a third element IS-NO 36, a subtractive counter 37, a multi-input element OR 38, and a first one-oscillator 39, the output of which is connected to the R input of the first trip 35, information input and input Record subtractive counter 37 are the first and second inputs of the parallel code to serial converter 24, the S input of the first trigger 35 is the third input of the parallel code converter 24 to serial, the second input One third IS-NE 36 element is the fourth input of the parallel-to-serial code converter 24, and the output is the output of the parallel-to-serial code converter 24.

The counting reversal circuit 25 is made of a serially connected digital comparator 40, a second trigger 41, and a fourth AND-NO element 42, the output of which is the second output of the counting reverse circuit 25, and a serially connected third trigger 43, whose S input is connected to the second digital output comparator 40, and the fifth IS-44 element, the output of which is the first output of the account reversal circuit 25, the second inputs of the fourth 42 and the fifth 44 AND-NOT elements are combined and are the first input of the account reversal circuit 25 that, the R inputs of the second 41 and third 43 flip-flops are combined and are the fourth input of the reversing circuit 25, and the first and second inputs of the digital comparator 40 are the third and second inputs of the account reversing circuit 25, respectively

The reset circuit 26 in O is made of a series-connected integrating RC element 45, a first inverter 46 and a second inverter 47, the input of the integrating RC element 45 is connected to a power source, and the outputs of the first 46 and second 47 inverters are the first and second outputs of the circuit 26 reset in O. The integrating RC-element 45 consists of series-connected resistor 48 and capacitor 49.

The sensor 28 of the presence of the monitored product is made of the first 50 and second 51 limit switches, the fourth trigger 52, the second 53 and the third 54 one-shot and two resistors 55 and 56, the first inputs of which are combined and connected to the power source, the second inputs are connected to S- and R The inputs of the fourth flip-flop 52 and the fixed contacts of the second 51 and first 50 limit switches, the inputs of the second 53 and third 54 one-shot ones are connected to the direct and inverse inputs of the fourth flip-flop 52 and are the first and third outputs of the presence sensor 28 ntroliruemogo article respectively, the outputs are second and fourth encoder 28 outputs the controlled presence of the article respectively, and movable contacts 50 and the limit switch 51 are connected to the earth rail gauge,

they are mechanically interconnected and are the input to the sensor 28 for the presence of the item being monitored.

Each converter 10–12 duration — the code is made of a sequence of fifth connected trigger 57, a sixth AND-HE element 58 and summing counter 59, the output of which is the output of converter 10 (11. 12} duration — a code, a S- and R -inputs of that trigger

5 57, the second input of the sixth element AND L AND-HE 58, the information enable permission input and the input Reset of the summing counter 59 are the first, second, third, fourth and fifth inputs of the converter 0

0 (11,12) duration - code accordingly Ultrasonic non-contact thickness gauge works as follows

When the power source of the gauge is switched on, the reset circuit 26 to O produces two paraphase short pulses. Impulse 1 from its first output cages elements OR-NOT 27, 33 and 34 resets counters 17, 59 and register 18 to zero. At the same time, in the absence of a controlled model (CI), trigger 52 is set to 1 and starts a one-shot 54, which resets to O counter 23 errors and triggers 41 and 43. At the same time, indicator 19 flashes zeros. Impulse O from the second output of the circuit

5 26 reset in O delay the start of synchronizer 1 for the duration of the reset pulse

After the pulse arrives from synchronizer 1, the triggers are set, and the pulse through the AND-HE element 58 is pulsed from the generator 14 counting pulses to the summing counters 59 until it is again set to O. This occurs after the arrival of an echo pulse and the formation of

5 of the pulse reset amplifier amplifier shaper 8 (Fig. 2). As a result, the number of pulses counted by each counter 59 in measuring channels 2 and 3 is proportional to the distance from transmitting 6 and receiving 7 transducers to KI 21, and in compensation channel 4 to the distance from transducers 6 and 7 to reflector 22. Since the process probing is periodic, then the counters 59 or the period to the period sum the received pulses. Summation is performed until a reset pulse arrives at the inputs R of the counters 59. This occurs through the number of periods N, equal to the division ratio of the counter 13 cycles per input

which receives pulses from the output of the compensation channel 4. The pulse from the counter output 13 cycles enters the inputs Z of the counters 59, as a result of which the information arrives at the inputs of the adder 15 and the subtractor 16. At the end of the information retrieval, the counters from the second output of the multiphase generator 30 are reset. in O. Then the cycles are repeated.

The operation of the circuit in the absence of an IC reduces to measuring and memorizing the error of setting the zero thickness gauge.

The position of the switches 50 and 51 for this case is shown in FIG. 3. At the same time, at the first output of the sensor 28, 1 is formed; at the third output O, the AND-NO element

29 at the first entrance is open, and the element AND- NOT 31 is closed.

The pulses from the output of the compensation channel 4 start the counter 13 cycles and through the number of periods N from the output of the latter, pulses are triggered through the NAND 29 element, which start the generator 30. The pulse from the first output of the multiphase generator

30 allows the recording of information in the counter 23 errors and the converter 24 parallel code to serial. The pulse duration at the output of the counter 13 cycles is chosen such that its active part partially coincides with the first pulse of the generator 30. At the same time, the information from the output of the subtractor 16 is recorded in the error counter 23 and the converter 24. The pulse duration at the output of the counter 13 cycles can be adjusted RC- elements in the amplifier-former 8

The rewriting cycles in counter 23 and transducer 24 are repeated while the CI is absent in the control zone.

When the thickness gauge is correctly adjusted and the IC is absent, the sum of the distances from the transmitting transducers 6 to the receiving transducers 7 in the measuring channels is equal to the distance from the transmitting transducer to the receiving one in the compensation channel, therefore the code of the output number of the subtractor 16 is zero. However, if there is a detuning (for example, from displacement of sensors caused by vibration, not accurate installation after repair or under the influence of different heating of sensors by the monitored product), a code appears at the output of the subtractor and an error counter 23 is written. not equal to zero

The compensation stack 4 is used to start the estimator of 13 cycles and to output information from the following considerations. According to the principle- / action of the thickness gauge, the echo pulse in the compensation channel 4 comes after the echo pulses in the measuring

channels 2 and 3. Therefore, by the time of the occurrence of the N-ro echo impulse and the start of the counter 13 (when the pulses arrive at the inputs for permitting the reading of information of the counters 59), the information in all summing counters 59 is already recorded for all N periods.

The operation of the circuit in the thickness measurement mode is reduced to the measurement of the thickness of the IC, taking into account the error in setting the zero thickness gauge determined in the absence of the IC. When the CI enters the control zone, it switches the limit switches 50 and 51, the trigger 52 is set to O, the first and third outputs of the sensor 28 are set to O and

5 1, respectively, and the second one-shot 53 is triggered by a negative differential and produces a single pulse. The latter, through the element OR-NOT 27, resets the summing counters 59, which, with the arrival of the first (after the occurrence of CI in the control zone) pulse of the synchronizer 1, begin counting the number of pulses, as described.

Through N cycles of synchronizer operation

5 1 from the counter 13 cycles, the second multi-phase generator 32 is started via the second element IS-HE 31 and generates four pulses in succession. All of them appear in time in the Nth period, in

0 from the N-ro echo impulse, formed by the compensation channel 4, or until the end of the N-ro period. The first pulse from the first output of the second multi-phase generator 32 records in the counter 17

5 results, the second pulse from the second output starts the converter 24. The last one converts the parallel code recorded in the 23 error counter into the number of pulses proportional to the code, which

0 is fed through the reversal counting circuit 25 to the summing and subtracting inputs of the result counter 17 and added to the previously recorded code (or subtracted from it). As a result, the output of the counter 17

5, a code is generated that is proportional to the thickness of the CI, taking into account the error of setting the thickness gauge zero. The third pulse from the output of the second multi-phase generator 32 records information in register 18. and the indicator 19 illuminates it. The fourth pulse of the multi-phase generator 32 resets the result counter 17 and the sum counter 57 to zero. Error number code in meter 23 in the thickness measurement mode is not

5 is changed until KI leaves the control zone. The code is reset to O only when switching to the zero-measurement error measurement mode. This operation is performed as follows: the fourth trigger 52, when entering the error measurement mode, is set

in 1 (Fig. 3). A negative differential from its inverse output triggers the third single-vibrator 54, and the pulse from the output of the latter through the element IL AND-NOT 27 resets the counters 59 to O.

The operation of the reversal counting circuit 25 is as follows. Digital comparator 40 compares the codes of numbers on the first and second inputs, and the comparison result in the form of 1 or O (or O and 1) from its outputs goes to the fourth 42 and fifth 44 AND-NOT elements through the second 41 and third 43 triggers. After the converter enters the second input of the parallel code 24 into a serial pulse from the second output of the multiphase generator 32 allowing the code conversion, the generator 14 pulses through the third input of the measurement results correction block 20 and the AND-NOT element 36 arrive at the second inputs of the AND-NOT elements 42 and 44 As a result, 1 is generated at the output of one of the AND-HER elements 42 and 44, and the same pulse sequence as at the first input of the converter 24 is output at the other. If the summing input of the counter 17 is fed in series pulse, and at the subtractive input there is 1, the counter operates in the mode of adding the number recorded by the information input D with the number of pulses arriving at the summing input. If the error sign changes, the counter 17 operates in the subtraction mode. The counter 17 appears, and the indicator 19 reflects the thickness measurement without the error of setting the thickness gauge zero.

The contactless thickness gauge allows to exclude from the measurement result systematic errors caused by changes in the base between the transmitting and receiving transducers of the measuring and compensation channels during the measurement of external factors (vibration, temperature, etc.).

Claims (1)

Claim 1. Ultrasonic contactless thickness gauge containing synchronizer, first and second measuring and computation channels, each made of a series of electro-acoustically connected generator of probing pulses, transmitting transducer, receiving transducer and amplifier - former, and the time measuring unit made from the first, second and third transducers duration - code, counter of results, indicator of results, counter of cycles and generator of calculating pulses, the synchronizer output is connected to the inputs of the probing pulse generators and to the first inputs of the first, second and third converters duration - code, the outputs of amplifiers-drivers are connected to the second inputs of the first, second and third converters duration - code, respectively, the output of the generator of counting pulses is connected to the third inputs The first, second, and third transducers are a duration code, characterized in that. In order to improve accuracy, the time measuring unit is equipped with a series-connected adder and a measurement result correction unit, a subtractor, the first input of which is connected to the output of the adder, and a register whose information input is connected to the output of the result counter, the output - to the input of the result indicator, the second input of the correction unit measurement results are connected to the second input of the reader and the output of the third converter; the duration — the code of the third input — to the output of the counting pulse generator, the fourth input — to the information input of the result counter and the output of the subtractor, the fifth input is intended for mechanical communication with the controlled product the sixth input is connected to the fourth inputs of the first, second and third transducers duration - code and output of the cycle counter, the first output - to the fifth inputs of the first, second and third transducers duration - code second output - to input Record 1 of the register, third output - to input Record result counter, fourth output - to the control input of the synchronizer fifth, sixth and seventh outputs - to the inputs Reset, subtracting and summing the counters of the results, respectively, the first and second inputs of the adder are connected to the outputs of the first and second transducers duration - the code, respectively, and the input of the cycle counter - to the output of the amplifier of the compensation channel 2 A thickness gauge according to claim 1, which is a measure that the measurement result correction block is made of serially connected error counter, parallel code to serial converter, and account reverse circuits, serially connected reset circuits in O and the first OR-NOT element, the output of which is the first output of the measurement results correction block, the sensor of the product under test, connected in series, the first AND-IE element and the first multiphase generator, connected in series the AND-NOT element and the second multi-phase generator, the second and third OR-NOT elements, the first inputs of which are combined and connected to the first output of the reset circuit in O, and the outputs are the second and fifth output of the measurement results correction unit, respectively, the second and third The inputs of the counting reversal circuit are the second and first inputs of the measurement result correction block, the fourth input is connected to the Reset error counter input, to the second input of the first OR-NOT element, and to the second output of the monitored product and, the first and second outputs are the sixth and seventh output of the measurement result correction block, the first input of the second element IS-NOT is connected to the third output of the sensor of the presence of the monitored product, the second input is combined with the second input of the first element AND-NOT and is the sixth input the measurement result correction unit, the first output of the first multi-phase generator is connected to the input Recording the error counter and the second input of the parallel code converter to the serial one, the second output to the third input of the first element OR -NON, the first output of the second multiphase generator is the third output of the measurement result correction block, the second output is connected to the third input of the parallel code to serial converter, the third output to the second input of the second OR element, the fourth output to the second input of the third element OR -NOT and the fourth input of the first element ORI, the sensor input of the presence of the monitored product is intended for mechanical communication with the monitored product and is the fifth input of the measurement result correction unit, the fourth sensor output of the product being monitored is connected to the fifth input of the first element OR — NOT, the error counter information input is the fourth input of the measurement result correction block, the fourth input of the parallel code to serial converter is the third input of the measurement result correction block, and the second output of the reset circuit in O is the fourth output of the measurement correction block. Z. Tolshchinrmer on PP. 1 and 2, which differs from the fact that the parallel-to-serial-code converter is made of the first trigger connected in series, the third AND-NOT element, the subtractive counter, the multi-input the OR element and the first one-shot, the output of which is connected to the R input of the first trigger, the information input and the input of the subtractive counter are the first and second inputs of the parallel code to serial converter, the S input of the first trigger is the third input of the parallel code converter to serial, the second input of the third AND-NOT element is the fourth input of the parallel code converter to serial, and the output is the output of the parallel code converter consistent, 5 4, Thickness gauge according to PP, 1 and 2, that is, that the account reversal circuit is made of series-connected digital comparator, second trigger and fourth NAND element, the output of which is the second output of the reversal circuit, and the third trigger connected in series, the S- input of which is connected to the second output of the digital comparator, and the fifth element 5 AND-NOT, the output of which is the first output of the account reversal circuit, the second inputs of the fourth and fifth elements of the AND-NOT are merged and are the first input of the account reversal circuit, the R inputs of the second The 0 and third triggers are combined and are the fourth input of the counting reversal circuit, and the first and second inputs of the digital comparator are the third and second inputs of the reverse circuit 5 accounts, respectively. 5. The thickness gauge on PP. 1 and 2, that is, with the fact that the reset circuit in O is made of a series-connected integrating RC element, the first 0 of the inverter and the second inverter, the input of the integrating RC element is connected to a power source, and the outputs of the first and second inverters are the first and second outputs of the reset circuit in O, respectively. five 6. The thickness gauge on PP. 1 and 2, that is, with the fact that the sensor of the presence of the monitored product is made of the first and second limit switches, the fourth 0 trigger, second and third one-vibration and two resistors, the first inputs of which are combined and connected to a power source, the second inputs are connected to the S- and R-inputs of the fourth trigger and fixed contacts of the second and first limit switches, respectively, the inputs of the second and third one-shot are connected to the direct l invert outputs of the fourth trigger and are the first and third outputs of the sensor for the presence of a monitored product, respectively, the outputs are the fourth and second outputs of the sensor for the presence of the movable product, and the movable contacts of the limit switches are connected to the thickness gauge body, are mechanically connected to each other and are the sensor input Thebes. one "about.  fr CNJ "