JPS62209353A - Scanning type eddy current flaw detection apparatus - Google Patents

Abstract

PURPOSE:To attain to enhance an S/N, by a method wherein a large number of detection coils are simultaneously excited by one exciting circuit and the difference between the output signals of adjacent detection coils is read to set off effect due to the change in temp. or lift-off. CONSTITUTION:When the flaw 13 of a material 4 to be inspected is present between detection coils 5-2, 5-3, the outputs of a detection coil group, that is, detection signals C1, C2, C3, C4 are taken out. A differential amplifier inputs outputs D1, D2, D3, D4 to modulation circuits 7-1, 7-2...7-4 and said outputs are respective modulated by modulation signals Z-1, Z-2...Z-4 supplied in a time series fashion. The output (e) of each modulation circuit is taken out from an adder circuit 8 and synchronously detected by a synchronous detection circuit 9 and the output thereof is detected by an absolute value detection circuit 10 and held by a peak holding circuit 11 to be outputted.

Description

【発明の詳細な説明】 庄１」Ｊ夏す１止匠 この発明は、被検査材の表面付近の欠陥を検査する渦流
探傷装置であって、検出コイルを固定した状態において
多数の検出コイルを同時に励振することにより、被検査
材の進行方向に直角な一定幅の探傷を同時に行う装置に
関する。[Detailed Description of the Invention] This invention is an eddy current flaw detection device for inspecting defects near the surface of a material to be inspected, in which a large number of detection coils are installed in a fixed state. This invention relates to a device that simultaneously performs flaw detection in a constant width perpendicular to the direction of movement of a material to be inspected by simultaneously exciting the object.

ｌ米坐肢歪 被検査材の欠陥検出において、掻出コイルを移動する方
式では、ピックアップした信号をスリップリングや回転
トランス等の連結機構を介して取り出すので、かかる連
結機構において発生する各種の雑音成分のため、信号に
ノイズが混入したり、あるいは信号が減衰したりすると
いう欠点があった。In the method of moving a scraping coil when detecting defects in materials to be inspected for ischial limb strain, the picked up signal is extracted through a coupling mechanism such as a slip ring or a rotating transformer, so various noises generated in such coupling mechanism are avoided. Because of the components, there is a drawback that noise may be mixed into the signal or the signal may be attenuated.

かかる検出コイル移動型の欠点を除去したものとして、
検出コイルを固定してその代わりに被検査材を検出コイ
ルに対して移動させる検出コイル固定型が提案実施され
ている。そのうちの一つのタイプとして、多数の検出コ
イルを被検査材の表面付近に並列に並べて、これらを時
系列的に順次励振する方式、即ち、検出コイル固定・時
系列励振型がある。In order to eliminate the drawbacks of such a moving detection coil type,
A fixed detection coil type in which the detection coil is fixed and the inspected material is moved relative to the detection coil has been proposed and implemented. One of these types is a method in which a large number of detection coils are arranged in parallel near the surface of the material to be inspected and are sequentially excited in time series, that is, a fixed detection coil/time series excitation type.

、Ｏが７ンしようと　る口　占 しかしながら、上記検出コイル固定・時系列励振型にお
いては、■励振回路の温度特性のばらつきの差により検
査時間の経過とともに、ノイズレベルが変化し、これを
完全に除去することが困難であること、■相隣る検出コ
イルの出方信号の差を求める差動方式が採用できず、そ
の代わりに一定の補正信号を差し引く方式となり、各回
路の検出出力の温度変化による影響やリフトオフによる
影響を取り除くことが困難である。However, in the fixed detection coil/time-series excitation type described above, the noise level changes as the inspection time passes due to differences in the temperature characteristics of the excitation circuit, and this cannot be completely eliminated. ■It is not possible to adopt a differential method that calculates the difference between the output signals of adjacent detection coils, and instead a method of subtracting a fixed correction signal is used, which reduces the It is difficult to eliminate the effects of temperature changes and lift-off.

この発明は上記事情にかんがみてなされたちので、多数
の検出コイルを一つの励振回路により同時励振すること
でもって、相隣る検出コイルの出力信号の差を読み取り
、温度変化やリフトオフによるｋＷを相殺することによ
り、Ｓ　／Ｎ比を高くするとこのできる走査型渦流探傷
装置を提供することを目的としている。This invention was made in view of the above circumstances, and by simultaneously exciting a large number of detection coils with one excitation circuit, the difference in output signals of adjacent detection coils is read, and the kW caused by temperature changes and lift-off is canceled out. The object of the present invention is to provide a scanning type eddy current flaw detection device that can achieve this by increasing the S/N ratio.

ロド占　１　るた　の この発明に係る走査型渦流探傷装置は、被検査材の進行
方向と直行する成分を含む方向に配置されるとともに同
一振幅同一位相の高周波電力で同時に励振される検出コ
イル群と、各検出コイルと同調増幅器間に設けられ各検
出コイルの特性を補正する補正回路と、相互に一定の位
置関係にある検出コイルの出力の差分を取り出す差動増
幅器と、前記差動増幅器の出力を 但し、Ｐ＝１．２．３・・・　（Ｎ−１）の電圧でもっ
て時系列的に乗じる変調回路と、変調回路の出力を加算
する加算回路と、加算回路の出力を同期検波する同期検
波回路とを具備している。The scanning eddy current flaw detection device according to this invention by Ruta Ruta consists of a group of detection coils arranged in a direction including a component perpendicular to the traveling direction of a material to be inspected and simultaneously excited with high frequency power having the same amplitude and phase. a correction circuit provided between each detection coil and the tuned amplifier to correct the characteristics of each detection coil; a differential amplifier for extracting the difference between the outputs of the detection coils that are in a fixed positional relationship with each other; A modulation circuit that multiplies the output in time series by a voltage of P = 1.2.3... (N-1), an addition circuit that adds the outputs of the modulation circuit, and synchronous detection of the output of the addition circuit. It is equipped with a synchronous detection circuit.

負す１ 相互に一定の位置関係にある各検出コイルから取り出さ
れた検出信号は差動増幅器でもってその差分が出力され
る。この出力は上記電圧でもって時系列的に乗算された
あと、その出力を加算したあと、同期検波される。Negative 1 The difference between the detection signals taken out from the detection coils that are in a fixed positional relationship with each other is outputted by a differential amplifier. This output is multiplied by the above voltage in time series, the outputs are added together, and then synchronous detection is performed.

１韮■ 第１図はこの発明の一実施例を示すブロックダイヤグラ
ムである。1. Figure 1 is a block diagram showing one embodiment of the present invention.

図において、１は矩形波出力ａを発振する標準クロック
回路、２は同調増幅回路、３は前記矩形波出力ａを分周
する分周回路である。３−１．３−２３−３　　・・・
、３−Ｎは各検出コイルの両端電圧の振幅と位相を揃え
るために設けた補償回路であって、例えばＴ型フィルタ
である。この補償回路３−１．３−２．３−３　　・・
・、３−Ｎを介して前記同調増幅回路２の出力すを検出
コイル群５−１．５−２．５−３　　・・・・、５−Ｎ
に送り出す。In the figure, 1 is a standard clock circuit that oscillates a rectangular wave output a, 2 is a tuned amplifier circuit, and 3 is a frequency divider circuit that divides the frequency of the rectangular wave output a. 3-1.3-23-3...
, 3-N is a compensation circuit provided to align the amplitude and phase of the voltage across each detection coil, and is, for example, a T-type filter. This compensation circuit 3-1.3-2.3-3...
A coil group 5-1.5-2.5-3 detects the output of the tuned amplifier circuit 2 via .., 3-N.
send to.

４は被検査材、１３は被検査材上の欠陥であり、この場
合においては、被検査材４は検出コイル群に対して第２
図の矢印方向に移動する。4 is the material to be inspected, 13 is a defect on the material to be inspected, and in this case, the material to be inspected 4 is second to the detection coil group.
Move in the direction of the arrow in the diagram.

６−１．６−２．６−３　　・・・・、６−Ｎは相隣あ
う検出コイルからの信号の差分を取り出すための差動増
幅器であり、したがって隣接する分周回路に跨るように
接続されている。７−１　、？−２、？−３・・・・・
、７−Ｎは前記差動増幅器の出力を受けておのおのの信
号に 但し、Ｐ＝１．２．３・・・　（Ｎ−１）なる位相が１
８０度ずつずれた単発の周期的な信号を乗じるための変
調回路、１２は前記信号を変調回路７−１．７−２　、
？−３・・・・・、７−Ｎに送るための変調用信号発生
回路、８は変調回路７−１　、？−２，７−３・・・・
・、７−Ｎの出力を加算する加算回路である。6-1.6-2.6-3 ..., 6-N is a differential amplifier for extracting the difference between signals from adjacent detection coils, and therefore It is connected. 7-1,? -2,? -3・・・・・・
, 7-N receive the output of the differential amplifier and each signal has a phase of 1, where P=1.2.3... (N-1).
A modulation circuit for multiplying a single periodic signal shifted by 80 degrees, 12 a modulation circuit 7-1.7-2 for multiplying the signal;
? -3..., 7-N, 8 is a modulation signal generation circuit for sending to modulation circuits 7-1, ? -2,7-3...
. , 7-N.

９は加算回路８の出力ｅとサンプリングパルス発生回路
１４の出力をうけて同期検波する同期検波回路（または
サンプルホールド回路）、１０は同期検波回路の出力ｆ
を絶対値に変換する絶対値検波回路、１１は絶対値検波
回路の出力ｇを受けてこれを最終の出力信号りとして取
り出すピークホールド回路である。なお、ピークホール
ド回路１１の出力は例えばレコーダに送られる。9 is a synchronous detection circuit (or sample hold circuit) that performs synchronous detection upon receiving the output e of the adder circuit 8 and the output of the sampling pulse generation circuit 14, and 10 is the output f of the synchronous detection circuit.
11 is a peak hold circuit that receives the output g of the absolute value detection circuit and extracts it as a final output signal. Note that the output of the peak hold circuit 11 is sent to, for example, a recorder.

第３図を参照しつつ、回路の動作説明を行う。The operation of the circuit will be explained with reference to FIG.

まづ、被検査材４の欠陥１３が検出コイル５−２と５−
３のあいだにあるので、検出コイル群からの出力、即ち
、検出信号Ｃ１、Ｃ２、Ｃ３、Ｃ４等は図示するように
なる。また差動増幅器の出力Ｄ１、Ｄ２、Ｄ３、Ｄ４は
同図に示すようになる。差動増幅器の出力ＤＩ、Ｄ２、
Ｄ３、Ｄ４は各変調回路７−１．７−２．７−３　、？
−４に入力して時系列的に供給される変調信号Ｚ−１、
Ｚ−２、Ｚ−３、Ｚ　−４でもってそれぞれ変調される
ので、加算回路８から取り出される出力ｅは同図のよう
になる。また同期検波回路９の出力ｒ、絶対値検波回路
１０の出力ｇも同図のようになる。First, the defect 13 of the inspected material 4 is detected by the detection coils 5-2 and 5-.
3, the outputs from the detection coil group, that is, the detection signals C1, C2, C3, C4, etc., are as shown in the figure. Further, the outputs D1, D2, D3, and D4 of the differential amplifier are as shown in the same figure. Differential amplifier output DI, D2,
D3 and D4 are each modulation circuit 7-1.7-2.7-3, ?
-4, the modulated signal Z-1 is inputted in a time-series manner,
Since they are each modulated by Z-2, Z-3, and Z-4, the output e taken out from the adder circuit 8 is as shown in the figure. Further, the output r of the synchronous detection circuit 9 and the output g of the absolute value detection circuit 10 are also as shown in the figure.

また前記同期検波回路９°、絶対値検波回路１０、ピー
クホールド回路１１を２種類設け、位相が９０゜異なっ
た２種類のサンプリングパルスで同期検波をすることに
より同時にＸ方向（励振位相と同位相）、Ｙ方向（励振
位相に対して９０°ずれた位相）の同期検波出力を得る
こともできる。In addition, two types of synchronous detection circuit 9°, absolute value detection circuit 10, and peak hold circuit 11 are provided, and by performing synchronous detection with two types of sampling pulses whose phases differ by 90°, simultaneous detection can be performed in the X direction (in phase with the excitation phase). ), it is also possible to obtain a synchronous detection output in the Y direction (phase shifted by 90° with respect to the excitation phase).

なお、検出コイルの構成として励振巻線と検出巻線を兼
用せずに、これらを個別に構成することもできる。It should be noted that the detection coil may be configured to have an excitation winding and a detection winding, but not to use both of them, and to configure these separately.

逸ｊＢり九果 この発明の走査型渦流探傷装置は、被検査材の進行方向
と直行する成分を含む方向に配置された多数個の検出コ
イルに同一振幅同一位相の高周波電力を加えることによ
り同時励振しているので、スリップリングや回転トラン
ス等あ機構部分を使用しない。したがって、かかる機構
に基づいて発生していた各種のノイズは本装置では発生
するとこはない。また各検出コイルの端子間には　相互
に一定の位置関係にある各検出コイルから取り出された
検出信号は差動増幅器でもってその差分が出力される。The scanning eddy current flaw detection device of the present invention simultaneously applies high frequency power of the same amplitude and phase to a large number of detection coils arranged in a direction including a component perpendicular to the traveling direction of the inspected material. Do not use mechanical parts such as slip rings or rotating transformers because they are excited. Therefore, the various noises that are generated based on such a mechanism will not occur in this device. Further, between the terminals of each detection coil, the difference between the detection signals taken out from each detection coil which is located in a fixed positional relationship with respect to each other is outputted by a differential amplifier.

この出力は上記電圧でもって時系列的に乗算されたあと
、その出力を加算したあと、同期検波されるように構成
しであるので、機構が従来に比べて簡単である。したが
って装置全体として安価に製造することが可能である。This output is multiplied by the above voltage in time series, the outputs are added, and then synchronous detection is performed, so the mechanism is simpler than the conventional one. Therefore, the entire device can be manufactured at low cost.

【図面の簡単な説明】[Brief explanation of drawings]

第１図はこの発明の一実施例であるブロックダイヤグラ
ム、第２図は被検査材と検出コイルの位置関係を示す概
念図、第３図は第１図における各部の信号の波形図であ
る。 ■　・・・標準クロック回路、２・・・同調増幅器回路
、３　・・・分周回路、３−１．３−２．３−３・・・
、３−Ｎ　　・・・補償回路、４　・・・被検査材、５
−１．５−２、５−３　　・・・・、５−Ｎ　　・・・
検出コイル、６−１．６−２．６−３　　・・・・、６
−Ｎ　・・・差動増幅器、７−１．７−２．７−３　・
・・・・、７−Ｎ　・・・変調回路、８・・・加算回路
、９　・・・同期検波回路、１０・・・絶対値検波回路
、１１・・・ピークホールド回路、１２・・・変調用信
号発生回路、１３・・・被検査材の欠陥、１４・・・サ
ンプリングパルス発生回路。 特許出願人　株式会社島津製作所 代理人　弁理士　大　西　孝　治 出力 第１図 第２図 第３図FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is a conceptual diagram showing the positional relationship between the inspected material and the detection coil, and FIG. 3 is a waveform diagram of signals at various parts in FIG. 1. ■... Standard clock circuit, 2... Tuned amplifier circuit, 3... Frequency divider circuit, 3-1.3-2.3-3...
, 3-N...compensation circuit, 4...material to be inspected, 5
-1.5-2, 5-3 ..., 5-N ...
Detection coil, 6-1.6-2.6-3 ..., 6
-N... Differential amplifier, 7-1.7-2.7-3 ・
..., 7-N ... Modulation circuit, 8 ... Addition circuit, 9 ... Synchronous detection circuit, 10 ... Absolute value detection circuit, 11 ... Peak hold circuit, 12 ... Modulation signal generation circuit, 13... Defect in inspected material, 14... Sampling pulse generation circuit. Patent applicant Shimadzu Corporation Representative Patent attorney Takaharu Ohnishi Output Figure 1 Figure 2 Figure 3

Claims (3)

【特許請求の範囲】[Claims] （１）被検査材の進行方向と直行する成分を含む方向に
配置されるとともに同一の高周波電力で同時に励振され
る検出コイル群と、各検出コイルと同調増幅器間に設け
られ各検出コイルの特性を補正する補正回路と、相互に
一定の位置関係にある検出コイルの出力の差分を取り出
す差動増幅器と、前記差動増幅器の出力を Ｅ〔１＋ｓｉｎ（（φ・Ｔ）／（Ｎ−１））＋πＰ〕但
し、Ｐ＝１、２、３…（Ｎ−１） の電圧でもって時系列的に乗じる変調回路と、変調回路
の出力を加算する加算回路と、加算回路の出力を同期検
波する同期検波回路とを具備したことを特徴とする走査
型渦流探傷装置。(1) Characteristics of a group of detection coils arranged in a direction including a component perpendicular to the traveling direction of the inspected material and simultaneously excited with the same high-frequency power, and of each detection coil provided between each detection coil and a tuned amplifier. a correction circuit that corrects the difference between the detection coils, a differential amplifier that extracts the difference between the outputs of detection coils that are in a fixed positional relationship with each other, and an output of the differential amplifier that is expressed as E[1+sin((φ・T)/(N-1) ) + πP] However, P = 1, 2, 3... (N-1) A modulation circuit that multiplies in time series by voltages, an addition circuit that adds the outputs of the modulation circuit, and a synchronous detection of the output of the addition circuit. A scanning eddy current flaw detection device characterized by being equipped with a synchronous detection circuit. （２）前記検出コイルの位置関係は相隣りあうものであ
ることを特徴とする特許請求の範囲第１項記載の走査型
渦流探傷装置。(2) The scanning eddy current flaw detection apparatus according to claim 1, wherein the detection coils are positioned next to each other. （３）前記検出コイルの位置関係は一定間隔隔てたもの
であることを特徴とする特許請求の範囲第１項記載の走
査型渦流探傷装置。(3) The scanning eddy current flaw detection device according to claim 1, wherein the detection coils are spaced apart at a constant distance.