SU960616A1

SU960616A1 - Eddy-current resonance converter

Info

Publication number: SU960616A1
Application number: SU813229751A
Authority: SU
Inventors: Владимир Дмитриевич Остапенко; Николай Павлович Калинин
Original assignee: Предприятие П/Я А-3869; Моторостроительный Завод Им.Я.М.Свердлова
Priority date: 1981-01-04
Filing date: 1981-01-04
Publication date: 1982-09-23

Description

Изобретение относится к неразрушаю-. щему контролю и может быть использовано для определения качества поверхности материалов и изделий.The invention relates to non-destructive. monitoring and can be used to determine the surface quality of materials and products.

Известен вихретоковый преобразователь содержащий полый металлический корпус 5 расположенные в нем каркас с обмоткой и схему преобразования сигнала, состоящую из узкополосного усилителя и выходного каскада tl] .Known eddy current transducer containing a hollow metal housing 5 located in it a frame with a winding and a signal conversion circuit consisting of a narrow-band amplifier and an output stage tl].

Недостатком такого преобразователя ^1(:является низкая'точность контроля из-за наличия распределенных параметров мон-‘ тажа схемы преобразования сигналов.The disadvantage of such a converter ^{1 (:} is the low accuracy of the control due to the presence of distributed parameters for the installation of the signal conversion circuit.

Наиболее близким по технической сущ< 4 ности к изобретению является вихретоковый резонансный преобразователь, содержащий полый металлический корпус, расположенные в нем управляемый генератор высокой частоты, подключенный к ₂₍нему детектор, соединенные параллельно резонансный контур, выполненный в виде отрезка коаксиальной линии и катушки индуктивности, и цепь отрицательного ак² тивного сопротивления, включенные между общим проводом и входом детектора, а также подключенный к выходу детектора индикатор [2J .The closest in technical essence <4 to the invention is an eddy current resonant transducer containing a hollow metal casing, a controlled high-frequency generator located in it, connected to _{2 (} a detector connected to it in parallel, a resonant circuit made in the form of a piece of a coaxial line and an inductor, chain and negative ac tive ² resistance connected between the common conductor and the input of the detector and also connected to the output of the detector indicator [2J.

Целью изобретения является повышение точности контроля.The aim of the invention is to improve the accuracy of control.

Поставленная цель достигается тем, что преобразователь снабжен генератором пилообразного напряжения, подключенным к управляемому входу генератора высокой частоты и второму входу индикатора, и аттенюатором, включенным между выходом генератора высокой частоты и входом детектора.This goal is achieved in that the converter is equipped with a sawtooth voltage generator connected to a controlled input of the high frequency generator and the second input of the indicator, and an attenuator connected between the output of the high frequency generator and the detector input.

На чертеже представлена блок-схема вихретокового преобразователя.The drawing shows a block diagram of an eddy current transducer.

Преобразователь содержит соединенные последовательно генератор 1 пилообразного напряжения, генератор 2 высокой частоты, аттенюатор 3, соединенные параллельно резонансный контур 4: выполненный в виде отрезка коаксиальной линии и катушки индуктивности (не показаны), и цепь 5 отрицательного акThe converter contains a serrated sawtooth generator 1, a high frequency generator 2, an attenuator 3 connected in parallel to a resonant circuit 4: made in the form of a segment of a coaxial line and an inductor (not shown), and a negative circuit 5

960616 4 тииного сопротивления, включенные между выходом аттенюатора 3 и общим приводом, детектор 6 и индикатор 7, вход У которого подключен к детектору 6, а вход х соединен с генерато· j ром пилообразного напряжения. Все высокочастотные узлы размешены в полом металлическом корпусе 8.960616 4 thiine resistance, connected between the output of the attenuator 3 and the common drive, the detector 6 and the indicator 7, the input of which is connected to the detector 6, and the input x is connected to the sawtooth generator · j rum. All high-frequency nodes are housed in a hollow metal casing 8.

Вихретоковый резонансный преобразователь работает следующим образом. 10Eddy current resonant transducer operates as follows. 10

Генератор 2 высокой частоты вырабатывает электромагнитные колебания в области повышенных частот (0,031,5 ГТц). Частота колебаний генератора 2 высокой частоты периодически изме- 15 няется в зависимости от управляющего сигнала с выхода генератора 1 пилообразного напряжения. Частотно-модупированные колебания с выхода генератора высокой частоты через аттенюатор 3 по- 20 ступают на вход резонансного контура 4, связанного с цепью 5 отрицательного активного сопротивления, выполняющей роль умножителя добротности. Величина сигнала на резонансном контуре 4 зависит 25 от его добротности и степени расстройки частот генератора 2 высокой частоты и резонансного контура 4 и изменяется периодически с частотой колебаний генератора 1 пилообразного напряжения. Сиг- 30 нал на резонансном контуре 4 измеряется с помощью детектора 6, поступает в схему индикатора 7 и представляет собой амплитудно-частотную характеристику резонансного контура. ₃₅ The high-frequency generator 2 generates electromagnetic waves in the region of high frequencies (0.031.5 GTZ). The oscillation frequency of the high-frequency generator 2 is periodically changed 15 depending on the control signal from the output of the sawtooth voltage generator 1. Frequency-modulated oscillations from the output of the high-frequency generator through the attenuator 3 go to the input of the resonance circuit 4, connected to the negative active resistance circuit 5, which acts as a quality factor. The magnitude of the signal on the resonant circuit 4 depends 25 on its quality factor and the degree of frequency detuning of the high-frequency generator 2 and the resonant circuit 4 and varies periodically with the oscillation frequency of the sawtooth generator 1. The signal 30 on the resonant circuit 4 is measured using the detector 6, enters the circuit of the indicator 7 and represents the amplitude-frequency characteristic of the resonant circuit. ₃₅

При поднесении катушки индуктивности поверхности изделия (не показаны), в последнем наводятся вихревые токи, влияющие на параметры резонансного конту ра. В зависимости от качества поверхности изделия характер изменения параметров резонансного контура 4 оказывается различным, что проявляется в изменении резонансной частоты и добротности амплитудно-частотной характеристики контура, фиксируемой индикатором 7.When a surface inductor of a product is brought up (not shown), eddy currents are induced in the latter, affecting the parameters of the resonance circuit. Depending on the quality of the surface of the product, the nature of the change in the parameters of the resonant circuit 4 is different, which is manifested in a change in the resonant frequency and the quality factor of the amplitude-frequency characteristic of the circuit, fixed by indicator 7.

Предлагаемый преобразователь обеспечивает высокую точность контроля.The proposed converter provides high accuracy control.

Claims

The invention relates to non-destructive testing and can be used to determine the surface quality of materials and products. A eddy current converter containing a hollow metal case with a winding frame and a signal conversion circuit consisting of a narrowband amplifier and an output stage tl is known. The disadvantage of such a converter is the low control accuracy due to the presence of distributed settings for the signal conversion circuit. The closest in technical essence to the invention is an eddy current resonant transducer containing a hollow metal case, a high-frequency controlled oscillator located in it, a detector connected to it, connected in parallel to a resonant circuit made in the form of a coaxial line and inductance, and a negative circuit active resistance, included between the common wire and the detector input, as well as connecting to the detector output indicator 2}. . The goal of izofeteniya is to increase the accuracy of control. The goal is achieved by the fact that the converter is supplied with a sawtooth voltage generator connected to the controlled input of the high-frequency generator and the second input of the indicator, and an attenuator connected between the output of the high-frequency generator and the input of the detector. The drawing shows a block diagram of the eddy current transducer. The converter contains a sawtooth voltage generator -1 connected in series, a high frequency generator 2, an attenuator 3 connected in parallel resonant circuit 4: made in the form of a segment of a coaxial line and an inductance coil (not shown), and a negative active resistance circuit 5 connected between the attenuator output 3 and a common drive, the detector 6 and the indicator 7, the input of which is connected to the detector 6, and the input x is connected to a saw-tooth generator. All high-frequency nodes are located in a hollow metal case 8. The eddy current resonant converter operates as follows. High-frequency generator 2 generates electromagnetic oscillations in the high-frequency region (0, OZ1, 5 GHz). The frequency of the oscillator 2 of the high frequency periodically varies depending on the control signal from the output of the generator 1 sawtooth voltage. Frequency-modulated oscillations from the output of the high-frequency generator, through attenuator 3, are fed to the input of the resonant circuit 4, which is connected to the circuit 5, negative active resistance, which plays the role of the quality factor multiplier. The magnitude of the signal on the resonant circuit 4 depends on its quality factor and the degree of detuning of the gene (high frequency jam and resonant control 4 and varies periodically with the oscillation frequency of the oscillator 1 of the pilophase voltage. The signal on the resonant circuit 4 is measured with a detector 6 enters the indicator circuit 7 and is the acotitude-frequency characteristic of the resonant circuit. When the coil is brought up in the surface of the product (not shown), in the latter, eddy currents are influenced The resonant circuit varies depending on the surface quality of the product, the variation in the parameters of the resonant 4 turns out to be different, which manifests itself in a change in the resonant frequency and the goodness of the Koifrypa amplitude-frequency characteristic, fixed by indicator 7. The proposed transducer provides high accuracy of co-pulse. Invention An eddy current resonant converter containing a hollow metal case, located in it a controlled high-frequency generator, connected to it a detector op connected parallel to the resonant circuit, executed in the form of a coaxial segment, the pins and inductors, and a negative active resistance circuit connected between the common wire and the detector input, as well as the indicator connected to the detector's output, that, in order to improve the monitoring quality, it is equipped with a sawtooth generator connected to the controlled input of the high frequency generator and the second input of the indicator, and an attenuator connected between the output of the high frequency generator you and the input of the detector. Sources of information taken into account in the examination 1. USSR author's certificate number 540503, cl. QOl On 7/06, 1973.

2. USSR author's certificate number 6OO885, cl. G01 7/06, 1978. . (prototype).