SU968733A2

SU968733A2 - Device for ultrasonic testing of high-temperature media

Info

Publication number: SU968733A2
Application number: SU803213862A
Authority: SU
Inventors: Пранас-Бернардас Пранович Милюс; Станисловас Йонович Антанайтис; Йонас Юозович Буткус
Original assignee: Каунасский Политехнический Институт Им.Антанаса Снечкуса
Priority date: 1980-12-11
Filing date: 1980-12-11
Publication date: 1982-10-23

Description

Изобретение относится к контрольно-измерительной технике и может быть использовано для контроля параметров высокотемпературных газовых потоков.The invention relates to instrumentation and can be used to control the parameters of high-temperature gas flows.

По основному авт. св. Ν’ 794479 известно устройство для ультразвукового контроля высокотемпературных сред, содержащее два пьезопреобразо- . вателя, подключенных к блоку измерения, систему ввода пьезопреобразователей в исследуемую среду, амплитудный селектор и схему сравнения, причем оба пьезопреобразователя через амплитудный селектор и схему сравнения подключены ко входу системы ввода пьезопреобраэователей в исследуемую среду и второму входу блока измерений [ 1 ].According to the main author. St. Ν ’794479 known device for ultrasonic control of high-temperature environments, containing two piezoelectric transducer. the transducers connected to the measuring unit, the input system of the piezoelectric transducers into the medium under study, the amplitude selector and the comparison circuit, both piezoelectric transducers through the amplitude selector and the comparison circuit are connected to the input of the piezoelectric transducer input system into the medium under study and the second input of the measurement unit [1].

Недостатком известного устройства является низкая точность контроля, так как не обеспечивается измерение из-за большого акустического шума.A disadvantage of the known device is the low accuracy of control, since measurement is not provided due to the large acoustic noise.

Цель изобретения - повышение точности контроля.The purpose of the invention is to increase the accuracy of control.

Поставленная цель достигается тем, что устройство снабжено последовательно соединенными схемой задержки, вход которой подключен к выходу блока измерений, первым селектором, первым детектором, первым блоком памяти, измерителем отношения и блоком сравнения, последовательно соединенными инвертором, вход которого соединен с выходом схем задержки, вторым селектором, вторым детектором, вторым блоком памяти, выход которого подключен ко второму входу измерителя отношений, выход блока измерений соединен со входом блоков памяти, а третий вход его - с выходом блока сравнения.This goal is achieved in that the device is equipped with a series-connected delay circuit, the input of which is connected to the output of the measurement unit, a first selector, a first detector, a first memory unit, a ratio meter and a comparison unit connected in series with an inverter, the input of which is connected to the output of the delay circuits, the second a selector, a second detector, a second memory unit, the output of which is connected to the second input of the relationship meter, the output of the measurement unit is connected to the input of the memory units, and the third input is go - with the output of the comparison block.

На чертеже представлена блок-схема устройства.The drawing shows a block diagram of a device.

Устройство содержит пьезопреобразователи 1 и 2, подключенные к блоку 3 измерения, систему 4 ввода пьезопреобразователей в исследуемую среду, амплитудный селектор 5 и схему 6 сравнения, причем оба пьезопреобразователя 1 и 2 через амплитудный селектор 5 и схему 6 сравнения подключены ко входу системы 4 ввода пьезопреобразователей 1 и 2 и второму входу блока 3 измерений. Кроме того, устройство содержит последовательно соединенные схему 7 задержки,' вход которой подключен к выходу блока 3 измерений, первый селектор 8, первый детектор Э, первый блок 10 памяти, измеритель 11 отношений и блок 12 срав4 блока 3 измерения поступают на схему 7 задержки, в которой задерживаются на время и запускают первый селектор 8. На второй вход се5 лектора 8 на фоне шумов поступают импульсы, прошедшие исследуемую среду и принятые пьезопреобразователем 2.The device contains piezoelectric transducers 1 and 2 connected to the measurement unit 3, a piezoelectric transducer input system 4 to the test medium, an amplitude selector 5 and a comparison circuit 6, both piezoelectric transducers 1 and 2 through an amplitude selector 5 and a comparison circuit 6 are connected to the input of the piezoelectric transducer input system 4 1 and 2 and the second input of block 3 measurements. In addition, the device contains a series-connected delay circuit 7, the input of which is connected to the output of the measurement unit 3, the first selector 8, the first detector E, the first memory unit 10, the relationship meter 11 and the cp4 unit 12 of the measurement unit 3 are supplied to the delay circuit 7, in which the first selector is delayed for a while and is triggered 8. At the second input of the selector 8, pulses are transmitted against the background of noise, which have passed the medium under study and received by the piezoelectric transducer 2.

На выходе селектора 8 выделяется принятый импульс с временным сдвигом,At the output of the selector 8, the received pulse with a time shift is highlighted,

Ю относительно момента возбуждения пьезопреобразователя 1, равным С_о.Yu relative to the moment of excitation of the piezoelectric transducer 1, equal to _about .

Одновременно импульс с выхода схемы 7 задержки в инверторе 13 меняет свою нения, последовательно соединенные инвертор 13, вход которого соединен 95 с выходом схемы 7 задержки, второй селектор 14, второй детектор 15. второй блок 16 памяти, выход которого подключен ко второму входу измерителя 11 отношений. Выход блока 3 из- _Μмерений соединен со входами блока 10 и 16 памяти, а третий его вход - с выходом блока 12 сравнения.At the same time, the pulse from the output of the delay circuit 7 in the inverter 13 changes its state, the inverter 13 is connected in series, the input of which is connected 95 to the output of the delay circuit 7, the second selector 14, the second detector 15. the second memory block 16, the output of which is connected to the second input of the meter 11 relationship. The output of 3 measurements _Μ iz coupled to the input unit 10 and the memory 16, and its third input - to the output of 12 comparisons.

Устройство работает следующим образом. 25The device operates as follows. 25

В начальный момент времени на схему 6 сравнения поступают два опорных · напряжения l)p< и сигнал с выхода этой схемы сбрасывает показания блока 3 измерения, а также включает сис- ₃₀тему 4 ввода, при этом пьезопреобразователи 1 и 2 вводятся в.исследуемую высокотемпературную среду. Температура нагрева пьезопреобразователей 1 и 2 повышается, статический потенциал на обкладках пьезопреобразо- ³⁵вателей 1 и 2 за счет пироэффекта возрастает. Эти потенциалы подаются на входы амплитудного селектора 5, на выходе которого образуется напряжение, пропорциональное температуре на- ⁴⁰грева того пьезоэлемента, который больше нагрет. Когда напряжение на выходе схемы 6 сравнения станет рав ным опорному напряжению , на выходе этой схемы образуется нулевой потен- ‘ цйал, который прекращает работу блока. 3 измерения, а на систему 4 ввода подает команду вывода. В интервале времени между командами ввода и вы- . вода блок 3 измерений вырабатывает полярность на противоположную и запускает второй селектор 14. При этом на выходе селектора 14 выделяется только шум, принятый пьезопреобразователем 2. Сигналы с выходов селекторов 8 и 14 в виде импульсов и шума, соответственно, поступают на детекторы 9 и 15,на выходах которых имеют· место напряжения, соответствующие амплитудам принятых сигнала и шума. Эти напряжения в блоках 10 и 16 памяти запоминаются, после чего поступают на измеритель 11 отношения, в котором измеряется отношение сигнала к шуму. Напряжение 1)^ с выхода измерителя 11 подается на вход блока 12 сравнения, в котором происходит сравнение поступающего напряжения с эталонным U_5T. При выполнении условия 11^_т на выходе блока 12 появляется напряжение с высоким уровнем. Это напряжение поступает на третий вход блока 3 измерения, в котором в данном случае происходит измерение времени прохождения ультразвуковой волны через исследуемую среду, а также вычисление необходимых ее параметров, например температуры. В случае υθγ напряжение на выходе блока 12 сравнения равно нулю, и в блоке 3 измерения вычисление не происходит.At the initial moment of time, two reference voltages l) p <come to the comparison circuit 6 and the signal from the output of this circuit resets the readings of measurement unit 3 and also includes input system ₃₀ , while piezoelectric transducers 1 and 2 are introduced into the studied high-temperature Wednesday The heating temperature of piezoelectric transducers 1 and 2 increases, the static potential on the plates of piezoelectric transducers ³⁵ and 1 due to the pyroelectric effect increases. These potentials are applied to the inputs of the amplitude selector 5, whose output voltage is produced which is proportional to temperature HA overheating of piezoelectric element ^40, which is more heated. When the voltage at the output of the comparison circuit 6 becomes equal to the reference voltage, a zero potential is generated at the output of this circuit, which stops the operation of the unit. 3 measurements, and the input system 4 gives an output command. In the time interval between input and output commands. water, the measurement unit 3 generates the opposite polarity and starts the second selector 14. In this case, only the noise received by the piezoelectric transducer 2 is released at the output of the selector 2. The signals from the outputs of the selectors 8 and 14 in the form of pulses and noise, respectively, are fed to the detectors 9 and 15, at the outputs of which there are voltages corresponding to the amplitudes of the received signal and noise. These voltages in the blocks 10 and 16 of the memory are stored, after which they are sent to the ratio meter 11, in which the signal-to-noise ratio is measured. The voltage 1) ^ from the output of the meter 11 is fed to the input of the comparison unit 12, in which the incoming voltage is compared with the reference U _5T . When the condition 11 ^ _{t is} fulfilled, a voltage with a high level appears at the output of block 12. This voltage is supplied to the third input of the measurement unit 3, in which in this case the time of passage of the ultrasonic wave through the medium under study is measured, as well as the calculation of its necessary parameters, for example, temperature. In the case of υθγ, the voltage at the output of the comparison unit 12 is zero, and the calculation does not occur in the measurement unit 3.

Таким образом, предложенное устройство позволяет автоматически измерять параметры сред с высокой точностью, поскольку измерения проводят только при превышении заранее заданного соотношения сигнал-шум.Thus, the proposed device allows you to automatically measure the parameters of the media with high accuracy, since measurements are carried out only when exceeding a predetermined signal-to-noise ratio.

сигналы, которые поступают на излучающий пьезопреобразователь 1 и затем принимаются приемным пьезопреобразователем 2.the signals that enter the emitting piezoelectric transducer 1 and then are received by the receiving piezoelectric transducer 2.

В блоке 3 измерения по времени прохожденияф'р акустического сигнала через среду вычисляется ее температура. Одновременно импульсы с выходаIn block 3, measurements of the time it takes for the acoustic signal to pass through the medium, its temperature is calculated. Pulses from the output simultaneously

Claims

(5) DEVICE FOR ULTRASONIC CONTROL OF HIGH-TEMPERATURE MEDIA The invention relates to instrumentation engineering and can be used to control the parameters of high-temperature gas flows. According to the main author. St. № discloses an apparatus for ultrasonic testing of high-temperature media, comprising two piezoelectric transducers connected to the measuring unit, an input pezoprerbrazovateley system in the test medium, an amplitude selector and comparator circuit, the two piezoelectric transducers of the amplitude selector and scheme CPA Neny connected to the input of the input system of the transducers in the investigated medium and the second input of the measurement unit f 1 J. A disadvantage of the known device is the low control accuracy, since it is not measurable Due to the large acoustic noise. The purpose of the invention is to improve the accuracy of control. The goal is achieved by the fact that the device is equipped with a series-connected delay circuit, the input of which is connected to the output of the measurement unit, the first selector, the first detector, the first memory block, the ratio meter and the comparison unit, connected by an inverter whose input is connected to the output of the delay circuits , the second selector, the second detector, the second memory block, the output of which is connected to the second input of the ratio meter, the output of the measurement block is connected to the input of the memory blocks, and the third input one of it - with the output of the comparison block. The drawing shows the block diagram of the device. The device contains piezoelectric transducers 1 and 2, connected to the measurement unit 3, the system k for inputting piezoelectric transducers into the medium under study. amplitude selector 5 and comparison circuit 6, both piezo transducers 1 and 2 through amplitude selector 5 and comparison circuit 6 are connected to the input system i of the input piezo transducer I and 2 and the second input of the unit 3 measurements. In addition, the device contains successively connected delay circuit 7, the input of which is connected to the output of the measurement unit 3, the first selector 8, the first detector 9. the first memory unit 10, from the ratio meter 11 and the comparison unit 12, connected in series with the inverter 13 whose input is connected to the output of the delay circuit 7, the second selector 14, the second detector 15, the second memory block 16, the output of which is connected to the second input of the ratio meter 11. The output of the measurement unit 3 is connected to the inputs of the memory unit 10 and 16, and its third input is connected to the output of the comparison unit 12. The device works as follows. At the initial moment of time, two reference voltages DO U are supplied to the comparison circuit 6 and the signal from the output of this circuit resets the readings of the measurement unit 3 and also includes the input system, with the piezoelectric transducers 1 and 2 being input into the studied high-temperature environment. The heating temperature of piezo transducers 1 and 2 increases, the static potential on the plates of piezo transducers 1 and 2 due to the pyroelectric effect grows. These potentials are supplied to the inputs of the amplitude selector 5, the output of which produces a voltage proportional to the temperature of the heating of the piezoelectric element that is more heated. When the voltage at the output of the comparison circuit 6 becomes equal to the reference voltage U, the output potential of this circuit is zero potential, which stops the operation of the block. 3 measurements, and on the input system k sends an output command. In the time interval between the input and output commands, the measurement unit 3 generates signals that go to the radiating piezoelectric transducer 1 and then are received by the receiving piezoelectric transducer 2. In unit 3, measuring the passage time tfp of the acoustic signal through the medium, its temperature is calculated. Simultaneously, the pulses from the output of the measurement unit 3 arrive at the delay circuit 7, in which the first selector 8 is delayed and started. The second input of the selector 8 against the background of noise receives impulses that have passed the test medium and are received by the piezoelectric transducer 2. the received pulse with a time shift, relative to the time of excitation of the piezoelectric transducer 1, is equal to tTg. At the same time, the pulse from the output of the delay circuit 7 in the inverter 13 reverses its polarity and triggers the second selector 1. In this case, only the noise received by the piezoelectric transducer is released at the output of the selector 1

2. The signals from the outputs of the selectors 8 and 1A in the form of pulses and noise, respectively, arrive at detectors 9 and the outputs of which have a voltage corresponding to the amplitudes of the received signal and noise. These voltages in memory blocks 10 and 16 are memorized, and then fed to a ratio meter 11, in which the signal-to-noise ratio is measured. The voltage U from the output of the meter 11 is fed to the input of the comparison unit 12, in which the incoming voltage is compared with the reference voltage. When the condition is fulfilled and the output of the block 12 appears, the voltage is at a high level. This voltage goes to the third input of the measurement unit 3, in which in this case the measurement of the time of passage of the ultrasonic wave through the medium under study, as well as the calculation of its necessary parameters, such as temperature. In the case of U 11., the voltage at the output of comparison unit 12 is zero, and in measurement block 3, the calculation does not occur. Thus, the proposed device allows automatic measurement of medium parameters with high accuracy, since measurements are carried out only when the predetermined signal-to-noise ratio is exceeded. Claims of the invention A device for ultrasound monitoring of high-temperature media according to ed. St. N °, distinguished by the fact that, for the purpose of higher