JPH07260743A - Flaw detector - Google Patents
Flaw detectorInfo
- Publication number
- JPH07260743A JPH07260743A JP5174194A JP5174194A JPH07260743A JP H07260743 A JPH07260743 A JP H07260743A JP 5174194 A JP5174194 A JP 5174194A JP 5174194 A JP5174194 A JP 5174194A JP H07260743 A JPH07260743 A JP H07260743A
- Authority
- JP
- Japan
- Prior art keywords
- current
- magnetic field
- flaw
- measuring means
- inspection
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
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- Investigating Or Analyzing Materials By The Use Of Magnetic Means (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、誘導による探傷検査装
置に係り、特に、渦電流探傷などの誘導電流を発生する
ための励振コイルを排除して探傷性能を高めた探傷装置
に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flaw detection inspection apparatus by induction, and more particularly to a flaw detection apparatus having enhanced flaw detection performance by eliminating an excitation coil for generating an induced current such as eddy current flaw detection.
【０００２】[0002]
【従来の技術】従来の誘導電流を利用した探傷装置、と
くに渦電流探傷装置は、渦電流発生用の励振コイルと渦
電流によって誘導された磁場を測定する磁場測定器によ
り構成されている。この装置の構成を図５により説明す
る。発振器５１で得た電流を励振コイル５２に流し、検
査試料５３に渦電流を発生させる。渦電流によって誘導
された磁場をピックアップコイル５４を用いた磁場測定
器で測定する。もし、渦電流が誘導される領域に傷など
が存在すると、電流経路のインピーダンスが変化するの
で、誘導される渦電流の量に変化が生じることになり、
従って、ピックアップコイル５４の検出信号を平衡装置
５５、増幅器５６、検波器５７、直流増幅器５８、オシ
ログラフ５９、メータ６０、レベル弁別器６１、マーカ
６２、カウンタ６３等で構成される信号処理装置で変化
する値を測定することができる。このため、電磁誘導試
験法によると、磁場測定器の出力を測定することにより
傷の検出をすることができる。2. Description of the Related Art A conventional flaw detector utilizing an induced current, particularly an eddy current flaw detector, comprises an exciting coil for generating an eddy current and a magnetic field measuring instrument for measuring a magnetic field induced by the eddy current. The configuration of this device will be described with reference to FIG. The current obtained by the oscillator 51 is passed through the excitation coil 52 to generate an eddy current in the inspection sample 53. The magnetic field induced by the eddy current is measured by a magnetic field measuring device using the pickup coil 54. If a flaw or the like exists in the area where the eddy current is induced, the impedance of the current path changes, so the amount of the induced eddy current changes.
Therefore, the detection signal of the pickup coil 54 is processed by the signal processing device including the balancer 55, the amplifier 56, the detector 57, the DC amplifier 58, the oscillograph 59, the meter 60, the level discriminator 61, the marker 62, the counter 63, and the like. The changing value can be measured. Therefore, according to the electromagnetic induction test method, the flaw can be detected by measuring the output of the magnetic field measuring device.
【０００３】渦電流探傷装置は、特開昭６０−１９２２
５２号公報に記載のように、検査試料に渦電流を発生さ
せ、渦電流によって誘導される磁場を測定し、傷によっ
て生じるインピーダンスの変化を磁場の変化として検出
するものである。磁場測定器の出力変化を検出する方法
として、例えば、ブリッジを構成する平衡装置がある。
これは、４辺ブリッジの２辺を磁場測定器としたもの
で、傷が無い場合の２つの磁場測定器の出力でブリッジ
の平衡がとれるように調整しておく。ここで、もし傷が
あった場合には、磁場測定器の出力値が変化するので、
ブリッジの平衡が崩れることになり、これをもって傷を
検知するものである。An eddy current flaw detector is disclosed in Japanese Patent Laid-Open No. 60-1922.
As described in JP-A-52-52, an eddy current is generated in a test sample, a magnetic field induced by the eddy current is measured, and a change in impedance caused by a flaw is detected as a change in the magnetic field. As a method of detecting the output change of the magnetic field measuring device, for example, there is a balancing device that forms a bridge.
In this case, two sides of the four-sided bridge are used as magnetic field measuring devices, and adjustment is made so that the bridges can be balanced by the outputs of the two magnetic field measuring devices when there is no scratch. Here, if there is a scratch, the output value of the magnetic field measuring device changes, so
The bridge is out of balance, and this is used to detect scratches.
【０００４】従来の誘導電流を利用した渦電流探傷方式
では、励振コイルと検査試料との空隙距離の変動によっ
て誘導される渦電流量が変動し、また磁場測定器と検査
試料との空隙距離の変動によって磁場測定器の磁場測定
値も変動する。このため、励振コイルや磁場測定器の位
置が変動することによってもブリッジの平衡が崩れるの
で、ブリッジの平衡の崩れが傷の存在によるものである
か否かの弁別ができず、傷を誤検出する場合がある。In the conventional eddy current flaw detection method using induced current, the amount of eddy current induced by the variation of the air gap distance between the excitation coil and the inspection sample changes, and the air gap distance between the magnetic field measuring instrument and the inspection sample changes. The magnetic field measurement value of the magnetic field measuring device also changes due to the change. For this reason, the balance of the bridge is disrupted even if the position of the excitation coil or the magnetic field measuring device fluctuates.Therefore, it is not possible to discriminate whether or not the disruption of the bridge equilibrium is due to the existence of scratches, and the scratches are erroneously detected. There is a case.
【０００５】この場合、誤検出を低減する方法として、
「非破壊検査学会会誌第３０巻第１号」に記載されたよ
うに、磁場測定器の出力の信号処理により、解決を図っ
ている。これは、磁場測定器と検査試料との空隙距離の
変動に起因するものと、傷の存在に起因するものとに、
磁場測定器から出力される信号の位相情報に差異がある
ことを利用した方法である。In this case, as a method for reducing false detection,
As described in "Non-destructive Inspection Society Journal, Vol. 30, No. 1," the solution is achieved by signal processing of the output of the magnetic field measuring device. This is due to the variation in the gap distance between the magnetic field measuring instrument and the test sample and to the presence of scratches,
This is a method that utilizes the difference in the phase information of the signals output from the magnetic field measuring device.
【０００６】この方法では、磁場測定器と検査試料との
空隙距離の変動によって生じる位相情報を相殺するよう
に、信号処理法を構築し、磁場測定器と検査試料との空
隙距離が変動しても磁場測定器の出力に変動がないよう
にしておく。このため、検査試料ごとに、あらかじめ、
磁場測定器と検査試料との空隙距離が変動した場合の位
相情報を測定しておき、信号処理法に組み込んでおく必
要がある。しかしながら、磁場測定器と検査試料との空
隙距離が変動したことによる磁場測定器の出力変動を完
全に相殺できない場合には、傷を識別できなかったり、
あるいは傷が無いのに傷があると識別してしまうなど、
誤検出をしてしまう問題がある。In this method, a signal processing method is constructed so as to cancel the phase information generated by the change in the air gap distance between the magnetic field measuring instrument and the inspection sample, and the air gap distance between the magnetic field measuring instrument and the inspection sample is changed. Also, make sure that there is no fluctuation in the output of the magnetic field measuring device. Therefore, for each test sample,
It is necessary to measure the phase information when the gap distance between the magnetic field measuring device and the test sample changes and incorporate it into the signal processing method. However, if the output fluctuation of the magnetic field measuring device due to the change in the gap distance between the magnetic field measuring device and the inspection sample cannot be completely canceled out, the flaw cannot be identified,
Or, if there is no scratch, but identify it as a scratch,
There is a problem of false detection.
【０００７】一方、特開昭６０−１９２２５２号公報に
従来例として記載されている検査法として、検査試料に
直接電流を流すことによって、傷を検査する磁気探傷法
がある。これは、例えば、日本非破壊検査協会編日刊工
業新聞社発行の「非破壊検査便覧、第４編、磁気探傷
法」に記載のように、検査試料に直接電流を流して磁場
を発生させ、磁性体である検査試料から漏洩する磁場を
検出することにより探傷する方法である。検査試料に電
流を流すことによって発生した磁場は、磁性体である検
査試料に閉じ込められるが、もし傷などの不連続な状態
があった場合には、磁場は検査試料より漏洩することに
なる。そこで、漏洩したことを検出し、傷を検出する方
法である。On the other hand, as an inspection method described as a conventional example in Japanese Patent Laid-Open No. Sho 60-192252, there is a magnetic flaw detection method for inspecting a flaw by directly passing an electric current through an inspection sample. This is, for example, as described in "Non-Destructive Inspection Handbook, Vol. 4, magnetic flaw detection method" published by Nikkan Kogyo Shimbun, edited by the Japan Non-Destructive Inspection Association, in which an electric current is directly applied to the inspection sample to generate a magnetic field, This is a method for detecting flaws by detecting a magnetic field leaking from a test sample that is a magnetic body. The magnetic field generated by passing a current through the inspection sample is confined in the inspection sample, which is a magnetic body, but if there is a discontinuous state such as a scratch, the magnetic field will leak from the inspection sample. Therefore, it is a method of detecting a leak and detecting a flaw.
【０００８】地中の埋没管に地中電極から直接電流を流
す方法としては、特開昭６０−４４８６４号公報、特開
昭６２−１１３０５８号公報及び特開昭５９−１０８９
５４号公報等がある。As a method of directly supplying an electric current from an underground electrode to a buried pipe in the ground, JP-A-60-44864, JP-A-62-113058 and JP-A-59-1089 are known.
54, etc.
【０００９】従来の磁気探傷法では、いずれも検査試料
に閉じ込めた発生する磁場の漏洩より傷を検出するの
で、磁場を閉じ込めることのできない非磁性体では傷を
検出できないという問題がある。In all of the conventional magnetic flaw detection methods, since flaws are detected by leakage of a magnetic field generated in a test sample, there is a problem that a flaw cannot be detected by a nonmagnetic material that cannot confine a magnetic field.
【００１０】[0010]
【発明が解決しようとする課題】本発明の目的は、従来
技術の問題点を解決するために、電流により誘導された
磁場を測定する磁場測定器と検査試料面との空隙距離に
より検出器出力が変動することに起因する誤検出を防止
し、検査試料の材質が磁性非磁性を問わない探傷検査が
可能な探傷検査装置の提供にある。SUMMARY OF THE INVENTION It is an object of the present invention, in order to solve the problems of the prior art, that the detector output depends on the air gap between the magnetic field measuring device for measuring the magnetic field induced by the electric current and the inspection sample surface. The present invention provides a flaw inspection device capable of preventing erroneous detection due to fluctuations in the temperature and performing flaw inspection regardless of whether the material of the inspection sample is magnetic or non-magnetic.
【００１１】[0011]
【課題を解決するための手段】上記の目的は、検査試料
に均一に電流を通電する電極を取り付け検査試料に直接
電流を流すことによって、励振コイルを不用とし、直接
検査試料に電流を流した場合、流れる電流量を一定にで
き、また、流れる電流の空間分布は、検査試料の形状や
導電率により電流経路が決まり、例えば、軸対称で均一
な導電率の材質でできているパイプ状の検査試料では、
軸に垂直な断面での電流分布は、周方向には均一な分布
をしているから、このような検査試料に傷などが生じる
と、局所的に抵抗値が変化する部分が生じるので、傷の
近傍では電流経路が変化する。このため、検査試料に流
れる電流経路を所要の電流経路測定手段により測定する
ことにより、傷を検出することができ、このような構成
装置によって上記目的は達成できる。[Means for Solving the Problems] The above object is to attach an electrode to which a current is uniformly applied to a test sample and to directly flow the current to the test sample, thereby eliminating the need for an excitation coil and directly flowing the current to the test sample. In this case, the amount of current flowing can be made constant, and the spatial distribution of the current flowing determines the current path depending on the shape and conductivity of the test sample.For example, a pipe-shaped material made of axisymmetric and uniform conductivity can be used. In the test sample,
The current distribution in the cross section perpendicular to the axis has a uniform distribution in the circumferential direction, so if such an inspection sample is scratched, a portion where the resistance value changes locally occurs. The current path changes in the vicinity of. Therefore, the flaw can be detected by measuring the current path flowing through the inspection sample by the required current path measuring means, and the above object can be achieved by such a configuration device.
【００１２】[0012]
【作用】図２は、本発明の作用を説明する図である。
（ａ）では、検査試料を導体であるパイプ状の直管と
し、直管の外壁面に交流電流を流した状態を模式的に示
したものである。傷の無い部分では、直管の周方向には
抵抗値が一定であるため、周方向には均一な軸方向成分
の電流が流れている。しかし、径方向については、表皮
効果により、数１に示す表皮の深さδ程度の断面にだけ
電流が流れている。2 is a diagram for explaining the operation of the present invention.
In (a), the inspection sample is a pipe-shaped straight pipe which is a conductor, and a state in which an alternating current is passed through the outer wall surface of the straight pipe is schematically shown. In the non-scratched portion, the resistance value is constant in the circumferential direction of the straight pipe, so that a uniform axial component current flows in the circumferential direction. However, in the radial direction, due to the skin effect, the current flows only in the cross section having a depth δ of the skin shown in Formula 1.
【００１３】[0013]
【数１】 [Equation 1]
【００１４】そこで、直管の外壁面に傷がある部分を考
えると、電流は表皮効果により壁面に沿って流れる性質
があるため、外壁面上を流れてきた電流は、傷部分では
内壁に向かって流れ、その後は再び外壁面上を流れるこ
とになる。このため、直管の表面に流れた電流によって
誘導された磁場は、傷付近の部分と傷の無い部分とで
は、磁場の空間分布が異なる。すなわち、軸方向成分の
電流だけが存在する傷のない部分では、周方向成分の磁
場成分だけが存在し、径方向成分の磁場成分は存在しな
い。ところが、（ｂ）のように軸方向成分のほかに径方
向成分の電流が存在する傷のある近傍では、周方向成分
の磁場成分のほかに、径方向成分の磁場成分も存在する
ことになる。これを測定手段により測定することにより
傷を検出することができる。Therefore, considering a portion where the outer wall surface of the straight pipe has a scratch, since the current has a property of flowing along the wall surface due to the skin effect, the current flowing on the outer wall surface goes to the inner wall at the wound portion. And then again on the outer wall. Therefore, the magnetic field induced by the current flowing on the surface of the straight pipe has a different spatial magnetic field distribution between the portion near the flaw and the portion without the flaw. That is, in a portion where there is no flaw in which only the current in the axial direction exists, only the magnetic field component in the circumferential direction exists, and the magnetic field component in the radial direction does not exist. However, as in (b), in the vicinity of the flaw where the current in the radial direction exists in addition to the axial direction component, the magnetic field component in the radial direction component also exists in addition to the magnetic field component in the circumferential direction component. . A scratch can be detected by measuring this with a measuring means.
【００１５】[0015]
【実施例】以下、本発明を一実施例の図面に基づいて説
明する。図１の探傷検査装置は、発振器１で得た電圧を
検査試料であるパイプ状の直管８に間隔を置いて取り付
けた２つのリング状電極２−１と２−２の間に印加し、
直管８の外壁表面に電流を流す。直管８に流れる電流に
よって誘導される磁場を、直管の内部に挿入設置した磁
場測定器３により測定し、該磁場測定器３からの情報を
もとに傷検出部４で傷の検出をする。また、磁場測定器
３は、探傷検査制御部７により与えられた指令信号に基
づいて動作する測定器駆動部５によって直管８内を移動
走査されるよう構成されている。また、磁場測定器３の
位置は、測定器駆動部５らの制御信号にもとずいて位置
検出部６により求められる。さらに、探傷検査制御部７
において、傷検出部４と位置検出部６の２つの情報よ
り、傷が生じた場所を求める。DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings of an embodiment. The flaw detection inspection apparatus of FIG. 1 applies a voltage obtained by the oscillator 1 between two ring-shaped electrodes 2-1 and 2-2 attached to a pipe-shaped straight tube 8 as an inspection sample with a space therebetween,
An electric current is applied to the outer wall surface of the straight pipe 8. The magnetic field induced by the current flowing through the straight pipe 8 is measured by the magnetic field measuring device 3 inserted and installed inside the straight pipe 8, and based on the information from the magnetic field measuring device 3, the scratch detecting section 4 detects the scratch. To do. Further, the magnetic field measuring device 3 is configured to move and scan the inside of the straight pipe 8 by the measuring device driving unit 5 that operates based on the command signal given by the flaw detection inspection control unit 7. Further, the position of the magnetic field measuring instrument 3 is obtained by the position detecting section 6 based on the control signal from the measuring instrument driving section 5. Further, the flaw detection inspection control unit 7
In, the location of the scratch is obtained from the two pieces of information of the scratch detector 4 and the position detector 6.
【００１６】軸対称な構造と電気的な物性値をもつ直管
８では、リング状電極２−１，２−２により均一通電が
行なわれ印加された電圧により、直管８の周方向には均
一な軸方向成分だけの電流が流れていることになる。従
って電流によって誘導される磁場は軸方向成分だけであ
る。そこで、磁場測定器３での測定を、磁場の径方向成
分あるいは軸方向成分だけを測定する構造とすると、磁
場測定器３で径方向成分あるいは軸方向成分の磁場を測
定した場合には、その近傍で電流経路が変化したことを
示している。すなわち、磁場測定器３の出力がゼロでな
い場合には、その磁場測定器３の設置されている場所の
近傍では電流経路が変化したことになるので、したがっ
てその場所に傷があることが検出されることになる。In the straight tube 8 having an axially symmetric structure and electrical property values, uniform current is applied by the ring electrodes 2-1 and 2-2 and the applied voltage causes the straight tube 8 to move in the circumferential direction. It means that the current of only the uniform axial component is flowing. Therefore, the magnetic field induced by the current has only an axial component. Therefore, assuming that the measurement by the magnetic field measuring device 3 is a structure for measuring only the radial direction component or the axial direction component of the magnetic field, when the magnetic field measuring device 3 measures the radial direction component or the axial direction component, It shows that the current path has changed in the vicinity. That is, when the output of the magnetic field measuring device 3 is not zero, it means that the current path has changed in the vicinity of the place where the magnetic field measuring device 3 is installed. Therefore, it is detected that the place has a scratch. Will be.
【００１７】本実施例によると、検査試料に直接電流を
流すので、励振コイルが不用になり、常に一定の電流を
流すことができる。また、磁場測定器３と検査試料との
空隙距離の変動によって生じる磁場測定器３の出力が変
動した場合でも、検査試料が傷の無い健全な場合には存
在しない磁場成分の測定により傷を検出するので、磁場
測定器３の出力変動による傷の誤検出を排除することが
できる。According to the present embodiment, since the current is directly applied to the test sample, the exciting coil is unnecessary and a constant current can always be applied. Further, even when the output of the magnetic field measuring device 3 changes due to the change in the air gap distance between the magnetic field measuring device 3 and the inspection sample, a flaw is detected by measuring a magnetic field component that does not exist when the inspection sample is sound and has no defect. Therefore, it is possible to eliminate erroneous detection of scratches due to fluctuations in the output of the magnetic field measuring device 3.
【００１８】なお前記の磁場測定器３の位置測定を測定
器駆動部５から制御信号によって測定することについて
説明したが、エンコーダ等によって磁場測定器３の移動
量を検出し、検出信号を位置検出部６に入力して位置検
出をすることができる。The position measurement of the magnetic field measuring device 3 has been described by measuring the control signal from the measuring device driving section 5. However, the movement amount of the magnetic field measuring device 3 is detected by an encoder or the like, and the detection signal is detected. The position can be detected by inputting to the unit 6.
【００１９】次に図１に示した実施例における磁場測定
器３の位置を測定する位置検出器６の他の実施例を図４
において説明する。探傷装置制御部７より出力される制
御信号１０によって、発振器１は、鋸歯状的に周波数が
変化するように周波数変調され、この周波数変調された
電力を出力してリング状電極２−１，２−２に印加し、
直管８に鋸歯状的に周波数が変化する電流を流すととも
に、その一部をミキサ９に入力する。一方、磁場測定器
３で測定した磁場信号は、傷検出部４に伝達するととも
に、一部をミキサ９に入力する。ミキサ９では、発振器
１からの周波数変調信号と磁場測定器３で測定した磁場
の周波数変調信号との周波数の差を求める。この発振信
号と測定信号との差の周波数より磁場測定器３の位置を
電気的に求める構成である。このように、発振器１の発
振周波数ｆを時間変化させると、数１に示したように表
皮の深さδも時間変化するが、周波数ｆの掃引範囲を発
振器１の平均的な発振周波数に比べて十分小さくすれ
ば、表皮の深さの時間変化は小さくなり、検査試料を流
れる電流の分布変化の影響を小さくすることができるの
で、発振器１の発振周波数に周波数変調を重畳してもよ
い。Next, another embodiment of the position detector 6 for measuring the position of the magnetic field measuring device 3 in the embodiment shown in FIG. 1 will be described with reference to FIG.
Will be explained. The oscillator 1 is frequency-modulated by the control signal 10 output from the flaw detection device control unit 7 so that the frequency changes in a sawtooth shape, and the frequency-modulated power is output to output the ring-shaped electrodes 2-1 and 2-2. -2,
A current whose frequency changes in a sawtooth shape is passed through the straight pipe 8, and a part of the current is input to the mixer 9. On the other hand, the magnetic field signal measured by the magnetic field measuring device 3 is transmitted to the flaw detection unit 4 and a part thereof is input to the mixer 9. The mixer 9 obtains the frequency difference between the frequency modulation signal from the oscillator 1 and the frequency modulation signal of the magnetic field measured by the magnetic field measuring device 3. The position of the magnetic field measuring device 3 is electrically obtained from the frequency of the difference between the oscillation signal and the measurement signal. As described above, when the oscillation frequency f of the oscillator 1 is changed with time, the skin depth δ is also changed with time as shown in Equation 1, but the sweep range of the frequency f is compared with the average oscillation frequency of the oscillator 1. If it is made sufficiently small, the change in the skin depth with time becomes small, and the influence of the change in the distribution of the current flowing through the test sample can be reduced. Therefore, frequency modulation may be superimposed on the oscillation frequency of the oscillator 1.
【００２０】この動作を図５にて説明する。図５（ａ）
は、リング状電極２−１，２−２と磁場測定器３との位
置関係を示し、磁場測定器３をリング状電極２−１より
ｘだけ離れた位置に置いた場合を示している。また、図
５（ｂ）に発振器１で発振された電力の周波数ｆの時間
変化を示し、周波数ｆが周波数掃引周期時間Ｔで周波数
がｆ0からｆ0＋ｆ1まで鋸歯状的に変化していることを
示している。さらに、ミキサ９に入力する径方向の磁場
成分を測定した磁場測定器３の測定周波数ｆ′と発振器
１で得た発振周波数ｆの２つの信号を図５（ｃ）に示
す。図５（ｃ）に示したように、磁場測定器３で測定し
た測定周波数信号は、リング状電極２−１と磁場測定器
３との間の距離ｘの分だけ遅れて受信することになる。
これを数２に示す。This operation will be described with reference to FIG. Figure 5 (a)
Shows the positional relationship between the ring-shaped electrodes 2-1 and 2-2 and the magnetic field measuring device 3, and shows the case where the magnetic field measuring device 3 is placed at a position separated from the ring-shaped electrode 2-1 by x. Also shows time change shown in FIG. 5 (b) to oscillate by an oscillator 1 power frequency f, the frequency at the frequency f is the frequency sweep cycle time T varies in a sawtooth manner from f 0 to f 0 + f 1 It indicates that Further, FIG. 5C shows two signals, that is, the measurement frequency f ′ of the magnetic field measuring device 3 for measuring the radial magnetic field component input to the mixer 9 and the oscillation frequency f obtained by the oscillator 1. As shown in FIG. 5C, the measurement frequency signal measured by the magnetic field measuring device 3 is received with a delay of the distance x between the ring-shaped electrode 2-1 and the magnetic field measuring device 3. .
This is shown in Equation 2.
【００２１】[0021]
【数２】 [Equation 2]
【００２２】この遅れ時間ｔｄを測定することにより、
ｘの値すなわち磁場測定器３の位置を求めることができ
る。遅れ時間ｔｄは、発振周波数ｆと測定周波数ｆ′の
２つの信号の位相差に対応しているので、両者の差の周
波数ｆ′−ｆを測定すれば遅れ時間ｔｄを測定すること
ができる。そこで、ミキサ９は、入力した２つの信号の
周波数差ｆ′−ｆを出力するので、時々刻々変化する発
振周波数においても、磁場測定器３の位置が変化しない
かぎり、ミキサ９は一定の周波数ｆ′−ｆ＝ｆｄを出力
する。このため、発振器１の周波数掃引周期時間Ｔと周
波数の掃引範囲ｆ1は既知であるので、ミキサ９が出力
した差の周波数ｆｄを測定すれば、磁場測定器３の位置
を求めることができる。すなわち、位置検出部６１にお
いて数３の演算をすることにより、磁場測定器３の位置
ｘを求めることができる。By measuring this delay time td,
The value of x, that is, the position of the magnetic field measuring device 3 can be obtained. Since the delay time td corresponds to the phase difference between the two signals of the oscillation frequency f and the measurement frequency f ′, the delay time td can be measured by measuring the frequency f′−f of the difference between the two signals. Therefore, since the mixer 9 outputs the frequency difference f′−f between the two input signals, the mixer 9 keeps a constant frequency f unless the position of the magnetic field measuring device 3 changes even at an oscillation frequency that changes momentarily. ′ -F = fd is output. Therefore, since the frequency sweep period time T of the oscillator 1 and the frequency sweep range f 1 are known, the position of the magnetic field measuring device 3 can be obtained by measuring the difference frequency fd output from the mixer 9. That is, the position x of the magnetic field measuring device 3 can be obtained by performing the calculation of Expression 3 in the position detecting unit 61.
【００２３】[0023]
【数３】 [Equation 3]
【００２４】一方、この実施例の装置構成において、磁
場測定器３の位置の測定精度Δｘは、発振器１の発振周
波数の周波数掃引周期時間Ｔに比例し、周波数の掃引範
囲ｆ1に反比例しており、数４のように示すことができ
る。On the other hand, in the apparatus configuration of this embodiment, the measurement accuracy Δx of the position of the magnetic field measuring device 3 is proportional to the frequency sweep period time T of the oscillation frequency of the oscillator 1 and inversely proportional to the frequency sweep range f 1. And can be shown as in Equation 4.
【００２５】[0025]
【数４】 [Equation 4]
【００２６】この実施例において、周波数掃引範囲ｆ1
を変えると、表皮効果の影響により電流経路が異なる
が、周波数掃引周期時間Ｔを変えても、表皮効果の影響
はないので、周波数掃引周期時間Ｔを短くすると、磁場
測定器３の位置の検出精度を向上することができる。そ
こで、周波数掃引周期時間Ｔをリング状電極２−１，２
−２間の距離を進むのに要する時間程度に設定し、磁場
測定器３の位置をおおまかに測定した後、周波数掃引周
期時間Ｔを短くして、高精度で磁場測定器３の位置を測
定することができる。In this embodiment, the frequency sweep range f 1
, The current path differs due to the influence of the skin effect, but even if the frequency sweep cycle time T is changed, the skin effect does not affect. Therefore, if the frequency sweep cycle time T is shortened, the position of the magnetic field measuring device 3 is detected. The accuracy can be improved. Therefore, the frequency sweep cycle time T is set to the ring-shaped electrodes 2-1 and 2-2.
-Set the time to travel the distance between -2, measure the position of the magnetic field measuring device 3 roughly, then shorten the frequency sweep cycle time T and measure the position of the magnetic field measuring device 3 with high accuracy. can do.
【００２７】本実施例によると、自ら測定した磁場信号
により磁場測定器３の位置を同定することができる。ま
た、周波数掃引周期時間Ｔを変えることにより、位置の
粗測定と位置の微測定ができる。According to this embodiment, the position of the magnetic field measuring device 3 can be identified by the magnetic field signal measured by itself. Further, by changing the frequency sweep cycle time T, it is possible to perform coarse position measurement and fine position measurement.
【００２８】なお、磁場測定器３の位置の測定のための
周波数変調信号の発振は発振器１とは別の発振器を設け
てもよい。An oscillator different from the oscillator 1 may be provided for oscillation of the frequency modulation signal for measuring the position of the magnetic field measuring device 3.
【００２９】[0029]
【発明の効果】本発明によると、検査試料に検査部分の
両側から直接電流を流すので、励振コイルが不用にな
り、検査試料に常に一定の電流を流すことができる。ま
た、傷によって健全時とは異なる電流経路により誘導さ
れる磁場成分を測定することにより傷を検出するので、
磁場測定器と検査試料との空隙距離の変動によって生じ
る磁場測定器の出力変動による傷の誤検出を低減でき
る。また検査試料は導体であれば磁性・非磁性を問わな
いで検査が可能である。According to the present invention, since the current is directly applied to the inspection sample from both sides of the inspection portion, the excitation coil is not required, and a constant current can be always applied to the inspection sample. In addition, because the flaw is detected by measuring the magnetic field component induced by a current path that is different from the sound path due to the flaw,
It is possible to reduce erroneous detection of scratches due to fluctuations in the output of the magnetic field measuring device caused by fluctuations in the gap distance between the magnetic field measuring device and the test sample. In addition, if the inspection sample is a conductor, it can be inspected regardless of whether it is magnetic or non-magnetic.
【図１】本発明の一実施例の全体構成を示す図である。FIG. 1 is a diagram showing an overall configuration of an embodiment of the present invention.
【図２】本発明の検出原理を示す図である。FIG. 2 is a diagram showing a detection principle of the present invention.
【図３】本発明の基本構成を示す図１の構成要素のう
ち、磁場測定器の位置を測定する他の構成を示した図で
ある。FIG. 3 is a diagram showing another configuration for measuring the position of the magnetic field measuring device among the components of FIG. 1 showing the basic configuration of the present invention.
【図４】図３に示す磁場測定器の位置を測定する手段の
原理を示した図である。FIG. 4 is a diagram showing the principle of means for measuring the position of the magnetic field measuring device shown in FIG.
【図５】従来技術の渦電流探傷装置構成図である。FIG. 5 is a configuration diagram of a conventional eddy current flaw detector.
１…発振器、２−１，２−２…リング状電極、３…磁場
測定器、４…傷検出部、５…測定器駆動部、６…位置検
出部、７…探傷装置制御部、８…検査試料。DESCRIPTION OF SYMBOLS 1 ... Oscillator, 2-1 and 2-2 ... Ring-shaped electrode, 3 ... Magnetic field measuring device, 4 ... Scratch detection part, 5 ... Measuring device drive part, 6 ... Position detection part, 7 ... Flaw detection device control part, 8 ... Inspection sample.
Claims (7)
おいて、検査試料の探傷部分の両側に取付けられ電流を
均一に通電する電極と、該電極間に電圧を印加すること
により検査試料に直接電流を流すための電流源と、該電
流源により前記検査試料に流れる電流の経路を測定する
ための電流経路測定手段とを備え、該電流経路測定手段
により傷による電流経路の変化を測定することにより傷
を検出することを特徴とする探傷検査装置。1. In a flaw detection inspection apparatus for inspecting a flaw on a conductor surface, electrodes mounted on both sides of a flaw detection portion of an inspection sample, which carry a uniform current, and a voltage applied between the electrodes directly apply to the inspection sample. A current source for flowing a current, and a current path measuring means for measuring a path of a current flowing through the inspection sample by the current source, and measuring the change of the current path due to a scratch by the current path measuring means. A flaw detection inspection device characterized by detecting a flaw by means of a
た電極間に交流電圧を印加することにより表皮効果によ
って検査試料の表面に集中的に電流を流す電流源を設け
たことを特徴とする請求項１記載の探傷検査装置。2. The current source is provided with a current source that concentrates an electric current on the surface of the test sample by a skin effect by applying an AC voltage between electrodes attached to the test sample. Item 1. The flaw detection inspection device according to item 1.
に流れる電流によって誘導される磁場の空間分布の測定
より電流経路を測定する電流経路測定手段を設けたこと
を特徴とする請求項１記載の探傷検査装置。3. The current path measuring means is provided with a current path measuring means for measuring a current path by measuring a spatial distribution of a magnetic field induced by a current flowing through an inspection sample. Inspection equipment.
に流れる電流によって誘導される磁場の傷による磁場成
分を測定する磁場測定器を設けたことを特徴とする請求
項３記載の探傷検査装置。4. The flaw detection inspection apparatus according to claim 3, wherein a magnetic field measuring device for measuring a magnetic field component due to a flaw of a magnetic field induced by a current flowing through an inspection sample is provided as the current path measuring means.
おいて、検査試料の探傷部分の両側に取付けられ電流を
均一に通電する電極と、該電極間に電圧を印加すること
により検査試料に直接電流を流すための電流源と、該電
流源により前記検査試料に流れる電流の経路を測定する
ための電流経路測定手段と、該電流経路測定手段の位置
を測定する位置測定手段とを備え、前記電流経路測定手
段の傷情報と前記位置測定手段による位置情報とにより
傷を検出することを特徴とする探傷検査装置。5. A flaw detection inspecting apparatus for inspecting a flaw on a conductor surface, the electrodes being attached to both sides of a flaw detection portion of a test sample, which conducts a current uniformly, and a voltage applied between the electrodes to directly contact the test sample. A current source for passing a current, a current path measuring means for measuring a path of a current flowing through the inspection sample by the current source, and a position measuring means for measuring a position of the current path measuring means, A flaw inspection device characterized in that a flaw is detected based on flaw information of the current path measuring means and position information of the position measuring means.
測定手段を前記検査試料に沿って移動走査する駆動装置
の制御信号または駆動装置が検出した検出信号を情報と
して前記電流経路測定手段の位置を測定する位置測定手
段を設けたことを特徴とする請求項５記載の探傷検査装
置。6. The position measuring means uses the control signal of a driving device for moving and scanning the current path measuring means along the inspection sample or the detection signal detected by the driving device as information to determine the position of the current path measuring means. The flaw detection inspection apparatus according to claim 5, further comprising position measuring means for measuring.
兼用してあるいは別の電流源により周波数変調信号を発
振して前記検査試料に前記電極を通して発振周波数変調
信号を流し該発振した周波数変調信号と前記電流経路測
定手段の測定する周波数変調信号との時間差から前記電
流経路測定手段の位置を測定する位置測定手段を設けた
ことを特徴とする請求項５記載の探傷検査装置。7. The position measuring means also oscillates a frequency-modulated signal, which is also used as the current source or by another current source, and causes an oscillating frequency-modulated signal to flow through the electrode to the inspection sample to cause the oscillated frequency-modulated signal. The flaw detection inspection apparatus according to claim 5, further comprising position measuring means for measuring the position of the current path measuring means based on a time difference between the frequency modulated signal measured by the current path measuring means and the frequency modulated signal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5174194A JPH07260743A (en) | 1994-03-23 | 1994-03-23 | Flaw detector |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5174194A JPH07260743A (en) | 1994-03-23 | 1994-03-23 | Flaw detector |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH07260743A true JPH07260743A (en) | 1995-10-13 |
Family
ID=12895345
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5174194A Pending JPH07260743A (en) | 1994-03-23 | 1994-03-23 | Flaw detector |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH07260743A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH10307124A (en) * | 1997-05-08 | 1998-11-17 | Kajima Corp | Method and device for non-destructive inspection for body steel frame |
| JP2001194340A (en) * | 2000-01-11 | 2001-07-19 | Osaka Gas Co Ltd | Measuring instrument for state of cathodic protection |
| WO2010140525A1 (en) * | 2009-06-04 | 2010-12-09 | Ntn株式会社 | Hardening quality inspection device and hardening quality inspection method |
| WO2013003656A1 (en) * | 2011-06-30 | 2013-01-03 | Marquez Henry Palomino | Methods and apparatus for locating hidden or buried non-conductive pipes and leaks therefrom |
| CN108828056A (en) * | 2018-06-21 | 2018-11-16 | 中国矿业大学(北京) | The detection device of wirerope |
-
1994
- 1994-03-23 JP JP5174194A patent/JPH07260743A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH10307124A (en) * | 1997-05-08 | 1998-11-17 | Kajima Corp | Method and device for non-destructive inspection for body steel frame |
| JP2001194340A (en) * | 2000-01-11 | 2001-07-19 | Osaka Gas Co Ltd | Measuring instrument for state of cathodic protection |
| WO2010140525A1 (en) * | 2009-06-04 | 2010-12-09 | Ntn株式会社 | Hardening quality inspection device and hardening quality inspection method |
| WO2013003656A1 (en) * | 2011-06-30 | 2013-01-03 | Marquez Henry Palomino | Methods and apparatus for locating hidden or buried non-conductive pipes and leaks therefrom |
| CN108828056A (en) * | 2018-06-21 | 2018-11-16 | 中国矿业大学(北京) | The detection device of wirerope |
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