JPS6331003Y2 - - Google Patents
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- Publication number
- JPS6331003Y2 JPS6331003Y2 JP17117880U JP17117880U JPS6331003Y2 JP S6331003 Y2 JPS6331003 Y2 JP S6331003Y2 JP 17117880 U JP17117880 U JP 17117880U JP 17117880 U JP17117880 U JP 17117880U JP S6331003 Y2 JPS6331003 Y2 JP S6331003Y2
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- Prior art keywords
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- signal
- flaw
- frequency
- signals
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- 238000001514 detection method Methods 0.000 claims description 42
- 230000005284 excitation Effects 0.000 claims description 12
- 230000035945 sensitivity Effects 0.000 claims description 7
- 230000003321 amplification Effects 0.000 claims description 2
- 238000003199 nucleic acid amplification method Methods 0.000 claims description 2
- 238000006243 chemical reaction Methods 0.000 claims 1
- 238000010586 diagram Methods 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 238000007689 inspection Methods 0.000 description 2
- 230000035515 penetration Effects 0.000 description 2
- 239000000523 sample Substances 0.000 description 2
- 208000034656 Contusions Diseases 0.000 description 1
- 230000006378 damage Effects 0.000 description 1
- 230000003111 delayed effect Effects 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 230000010355 oscillation Effects 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
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- Investigating Or Analyzing Materials By The Use Of Magnetic Means (AREA)
Description
【考案の詳細な説明】 本考案は渦流探傷装置に関する。[Detailed explanation of the idea] The present invention relates to an eddy current flaw detection device.
渦流探傷は金属体の被検査体に存在する傷を非
破壊的に検出するために励磁コイルによつて交番
磁界を発生させて被検査体に渦電流を生じさせ、
傷などによるこの渦電流の変化を検出コイルのイ
ンピーダンスの変化として検出するものである
が、近年は次第により微小傷にいたるまでのより
厳密な探傷検査が要求されるようになつている。
しかるに、このように微小な傷をも高精度に検出
するためには検査目的の傷以外の要因による擬似
きず信号(雑音信号)との識別が重大な課題とな
つてくる。 Eddy current flaw detection uses an excitation coil to generate an alternating magnetic field to generate eddy currents in the inspected object in order to non-destructively detect flaws on the inspected metal object.
Changes in this eddy current due to scratches and the like are detected as changes in the impedance of the detection coil, but in recent years there has been a growing demand for more rigorous flaw detection inspections, even down to the smallest flaws.
However, in order to detect even such minute flaws with high precision, it is important to distinguish them from pseudo flaw signals (noise signals) caused by factors other than the flaws to be inspected.
即ち、金属被検査体には検出すべき傷、即ち、
破損、破壊、漏洩などに進展する有害な傷(ひ
び、割れ、局部的な減肉など)以外に、金属被検
査体の機械的強度に影響を及ぼさない無害な傷
(例えばハンドリング中に生ずる打ち傷など)が
多数点在するのが常である。このため検査目的の
傷が微小なものまでをも対象とするようになる
と、これらの無害な傷部分において検出される電
磁気的な不均一によつて生じる信号(擬似きず信
号=雑音信号が検出すべききず信号に対して大き
なウエイトを占めるようになつて、探傷の目的が
果せなくなる。また探傷検査中において探傷コイ
ルと被検査体との間に機械的振動が生じることが
あり、この振動によつて生ずる擬似きず信号によ
つても高精度のきず検出が阻害される。 In other words, there are flaws to be detected on the metal object, i.e.
In addition to harmful flaws (cracks, cracks, local thinning, etc.) that can lead to breakage, destruction, leakage, etc., harmless flaws that do not affect the mechanical strength of the metal object to be inspected (e.g. bruises that occur during handling) etc.) are usually scattered in large numbers. For this reason, as the inspection targets even the smallest flaws, signals generated by electromagnetic non-uniformity detected in these harmless flaws (pseudo flaw signals = noise signals) are detected. The flaws begin to take up a large weight in the flaw signal, making it impossible to achieve the purpose of flaw detection.Furthermore, mechanical vibrations may occur between the flaw detection coil and the object to be inspected during flaw detection, and this vibration Highly accurate flaw detection is also hindered by the resulting pseudo flaw signal.
本考案はこのような問題点を解決するためにな
されたものである。即ち、本考案では被検査体に
おける傷の検出感度は探傷コイルに供給される交
番電流の周波数に影響され、各周波数によつて有
害な傷の種類、無害な傷の種類、前記の振動など
に対する感度が異る点に着目して、単一の探傷コ
イルに同時に複数の周波数を印加して各周波数ご
とに対応した検出信号を同時に出力させ、これら
の複数の検出信号を加減算あるいは乗除算などの
適宜演算処理を行なつて擬似きず信号を抑制し有
害な傷の信号を強調して信号対雑音比を向上させ
ると共に、演算処理によつて傷の種類に応じた傷
信号の特徴付けを行なつて複数種の傷の識別もで
きるようにしたものである。 The present invention has been made to solve these problems. That is, in the present invention, the detection sensitivity of flaws on the object to be inspected is affected by the frequency of the alternating current supplied to the flaw detection coil, and depending on each frequency, it is possible to Focusing on the difference in sensitivity, multiple frequencies are applied to a single flaw detection coil at the same time, and detection signals corresponding to each frequency are output simultaneously, and these multiple detection signals are subjected to addition, subtraction, multiplication, division, etc. Appropriate arithmetic processing is performed to suppress pseudo flaw signals and emphasize harmful flaw signals to improve the signal-to-noise ratio, and the flaw signals are characterized according to the type of flaw through arithmetic processing. It is also possible to identify multiple types of scratches.
以下、図面に基いて本考案の実施例を説明す
る。 Embodiments of the present invention will be described below based on the drawings.
第1図は本考案の一実施例による渦流探傷装置
をブロツク図で示すもので、図中、101,10
2,……B,1oはそれぞれ任意の周波数の正弦波
信号を出力できる複数の高周波発振器、11はn
種の高周波発振器101,102,…,10oの出
力信号を混合する混合器、12はその帰還ループ
に出力電流制御のための電流−電圧変換用低抵抗
器13を備えて混合器11の出力を定電流電力増
幅する増幅器、14は増幅器12の出力によつて
被検査体Aに交番磁界を加えるために前記高周波
発振器101,102,…,10oのn種の周波数
を持つ電流が供給される渦流探傷用貫通コイル又
はプローブコイルの一次側の励磁コイル、15は
二次側の検出コイル、161,162,…,16o
は各一方の入力端子に検出コイル15に励磁コイ
ル14の駆動によつて生じた誘起電圧が加えられ
る差動増幅器、171,172,…,17oはそれ
ぞれ高周波発振器101,102,…,10oの出
力信号の一部を受けて被検査体Aの正常部での各
差動増幅器161,162,…,16oの出力が零
になるように打消し平衡用基準電圧信号を各差動
増幅器161,162,…,16oの各他の一方の
入力端子に供給する打消し電圧発生器、181,
182,…,18oは緩衝用抵抗器である。 FIG. 1 is a block diagram showing an eddy current flaw detection device according to an embodiment of the present invention.
2 ,...B, 1 o are multiple high frequency oscillators each capable of outputting a sine wave signal of an arbitrary frequency, 11 is n
A mixer 12 mixes the output signals of various high-frequency oscillators 10 1 , 10 2 , . An amplifier 14 for constant current power amplification of the output of the amplifier 12 has n types of frequencies of the high frequency oscillators 10 1 , 10 2 , . . . An excitation coil on the primary side of the eddy current flaw detection penetration coil or probe coil to which current is supplied; 15 is a secondary detection coil; 16 1 , 16 2 ,..., 16 o
17 1 , 17 2 , . . . , 17 o are high-frequency oscillators 10 1 , 10 2 , respectively. ..., 10 o so that the outputs of the differential amplifiers 16 1 , 16 2 , ..., 16 o in the normal part of the test object A become zero, so that the reference voltage for balance is cancelled. a cancellation voltage generator 18 1 , supplying a signal to the other input terminal of each differential amplifier 16 1 , 16 2 , . . . , 16 o ;
18 2 ,..., 18 o are buffer resistors.
191,192,…,19oは同調増幅器、20
1、202,…,20oは同調増幅器191,192,
…,19oの出力の振幅をそれぞれ適宜調整する
探傷感度調整器、211、212,…,21oは位
相検波器、221、222,…,22oはそれぞれ
高周波発振器101,102,…,10oの出力信
号の一部を受けて各周波数に対応した位相検波用
参照信号を適宜調整して設定する可変移相器、2
31、232,…,23oは遮断周波数を調整でき
る帯域波器、241、242,…,24oは帯域
波器231、232,…,23oの出力信号のそ
れぞれの振幅を調整する信号出力調整器、251、
252,…,25oは位相選択スイツチS1、S2,
…,Soの切替えによつて信号出力調整器241、
242,…,24oの出力信号を180゜反転する反転
増幅器である。 19 1 , 19 2 , ..., 19 o are tuned amplifiers, 20
1 , 20 2 , ..., 20 o are tuned amplifiers 19 1 , 19 2 ,
..., 19o are respectively phase detectors, 21 1 , 21 2 , ..., 21 o are phase detectors, 22 1 , 22 2 , ..., 22 o are high-frequency oscillators 10 1 , a variable phase shifter that receives a portion of the output signals of 10 2 ,..., 10 o and appropriately adjusts and sets a reference signal for phase detection corresponding to each frequency;
3 1 , 23 2 ,..., 23 o are band wave transducers whose cutoff frequencies can be adjusted, and 24 1 , 24 2 ,..., 24 o are band wave transducers 23 1 , 23 2 ,..., 23 o, respectively. signal output adjuster for adjusting amplitude, 25 1 ;
25 2 ,..., 25 o are phase selection switches S 1 , S 2 ,
..., the signal output regulator 24 1 by switching S o ,
This is an inverting amplifier that inverts the output signals of 24 2 , ..., 24 o by 180 degrees.
26は位相選択スイツチS1、S2,…,Soの切替
えによつて信号出力調整器241、242,…,2
4oの出力信号あるいは反転増幅器251、252,
…,25oによつて180゜位相を変えた信号を加減
算あるいは乗除算などの相関演算をして所望の特
徴付けを行つた信号を出力する演算器である。 26 is a signal output regulator 24 1 , 24 2 , . . . , 2 by switching the phase selection switches S 1 , S 2 , . . . , S o
4 o output signals or inverting amplifiers 25 1 , 25 2 ,
..., 25 o This is an arithmetic unit that performs correlation operations such as addition/subtraction or multiplication/division on signals whose phase has been changed by 180 degrees by o, and outputs a signal with desired characteristics.
27はリジエクシヨン動作設定器28によつて
設定されたしきい値よりレベルを超えた演算器出
力のみを通過させて低レベル周辺の背景雑音を遮
断するリジエクシヨン増幅器、29は記録増幅
器、30は記録計である。 27 is a reflexion amplifier that passes only the arithmetic unit output whose level exceeds the threshold value set by the reflexion operation setter 28 and blocks low-level peripheral background noise; 29 is a recording amplifier; 30 is a recorder. It is.
なお上記実施例では検出コイル15として絶対
値測定式の単コイルによる場合を例示している
が、第2図に示すように隣接比較コイルによつて
もよい。なお第2図において31〜34は緩衝用
抵抗器である。 In the above embodiment, a single absolute value measuring coil is used as the detection coil 15, but an adjacent comparison coil may be used as shown in FIG. In FIG. 2, 31 to 34 are buffer resistors.
次に上記実施例の動作を説明する。 Next, the operation of the above embodiment will be explained.
渦流探傷用貫通コイル又はプローブコイルの一
次側励磁コイル14は、n種の高周波発振器10
1,102,…,10oでそれぞれ適宜設定された
複数の周波数成分を持つた複数の正弦波電流で駆
動される。即ち、高周波発振器101,102,
…,10oから被検査体Aの検出すべき傷にそれ
ぞれ最適とされる異つた複数の周波数の正弦波発
振出力信号が出力されて混合器11で混合された
後、増幅器12で定電流電力増幅され、励磁コイ
ル14を駆動する。励磁コイル14と二次側検出
コイル15との間では被検査体Aが例えばライン
に沿つて搬送され、被検査体Aの各部が順次連続
的に検査される。励磁コイル14を流れる交番電
流によつて交番磁界が生じて検出コイルには誘起
電圧が生じるが、この誘起電圧信号は交番磁界内
に置かれた被検査体Aの傷の存在によつて影響さ
れて微小な変化を生じる。 The primary excitation coil 14 of the penetration coil for eddy current flaw detection or the probe coil is a high-frequency oscillator 10 of n types.
It is driven by a plurality of sinusoidal currents each having a plurality of frequency components appropriately set at 1 , 10 2 , . . . , 10 o . That is, high frequency oscillators 10 1 , 10 2 ,
..., 10o outputs sinusoidal oscillation output signals of a plurality of different frequencies, each of which is optimal for the flaw to be detected on the inspected object A, and after being mixed in the mixer 11, the constant current power is supplied to the amplifier 12. The signal is amplified and drives the excitation coil 14. The object A to be inspected is conveyed, for example, along a line between the excitation coil 14 and the secondary detection coil 15, and each part of the object A to be inspected is sequentially and continuously inspected. An alternating magnetic field is generated by the alternating current flowing through the excitation coil 14, and an induced voltage is generated in the detection coil, but this induced voltage signal is affected by the presence of flaws on the object A placed within the alternating magnetic field. causes minute changes.
この誘起電圧はn個の差動増幅器161,16
2,…,16oの各一方の入力端子に印加される。
そして他の一方の入力端子には各高周波発振器1
01,102,…,10oの出力の一部をそれぞれ
受けた打消し電圧発生器171,172,…,17
oからの打消し平衡用基準電圧が印加される。こ
れらの各打消し平衡用基準電圧はそれぞれの高周
波発振器101,102,…,10oの周波数に対
応して各差動増幅器161,162,…,16oの
出力が被検査体Aの正常部で零となるように位相
を逆にし振幅レベルを同一にするように設定され
ているので傷の存在によつてのみ各差動増幅器1
61,162,…,16oからは不平衡出力が生じ
る。被検査体Aの搬送に伴い被検査体Aにおける
傷などの点在によつて、また各周波数特有の検出
感度に応じて、これらの各差動増幅器161,1
62,…,16oからの出力信号は刻々と変化す
る。 This induced voltage is applied to n differential amplifiers 16 1 , 16
It is applied to one input terminal of each of 2 ,..., 16o .
And each high frequency oscillator 1 is connected to the other input terminal.
Cancellation voltage generators 17 1 , 17 2 , ..., 17 receiving part of the outputs of 0 1 , 10 2 , ..., 10 o , respectively
A reference voltage for canceling balance from o is applied. Each of these reference voltages for canceling balance corresponds to the frequency of each high-frequency oscillator 10 1 , 10 2 , ..., 10 o , and the output of each differential amplifier 16 1 , 16 2 , ..., 16 o Since the phase is set to be reversed and the amplitude level to be the same so that it becomes zero in the normal part of A, each differential amplifier 1 is
Unbalanced outputs are generated from 6 1 , 16 2 , ..., 16 o . These differential amplifiers 16 1 , 1 may vary depending on the presence of scratches or the like on the test object A as the test object A is being transported, or depending on the detection sensitivity specific to each frequency.
The output signals from 6 2 ,..., 16 o change every moment.
各差動増幅器161,162,…,16oの出力
信号は同調増幅器191,192,…,19oによ
つてそれぞれ更に増幅された後、位相検波器21
1、212,…,21oで検波されて探傷信号が復
調されれ低周波を呈するきず信号として抽出され
る。この位相検波において、各高周波発振器10
1,102,…,10oの出力の一部を受けて可変
移相器221、222,…,22oは各周波数に対
応して最も強調した抽出が行えるように適宜に位
相差を設定した位相検波用参照信号を出力する。 The output signal of each differential amplifier 16 1 , 16 2 , ..., 16 o is further amplified by a tuned amplifier 19 1 , 19 2 , ..., 19 o , and then a phase detector 21
1 , 21 2 , . . . , 21 o , the flaw detection signal is demodulated and extracted as a flaw signal exhibiting a low frequency. In this phase detection, each high frequency oscillator 10
1 , 10 2 , ..., 10 o , the variable phase shifters 22 1 , 22 2 , ..., 22 o adjust the phase difference as appropriate so that the most emphasized extraction can be performed corresponding to each frequency. Outputs the reference signal for phase detection that is set.
位相検波器211、212,…,21oの出力信
号は遮断周波数を適宜設定された帯域波器23
1、232,…,23oを通して不要雑音を低減す
ると共に設定された遮断周波数に応じて位相検波
後のきず信号の位相が適宜進められたり遅らされ
たりする。帯域波器231、232,…,23o
の出力は信号出力調整器241,242,…,24
oによつて演算器26への入力比を設定された後、
ある信号は反転増幅器251、252,…,25o
で180゜位相を反転され、他の信号は反転増幅器2
51、252,…,25oを介さずに演算器26へ
入力する。この操作は後述するスイツチS1、S2、
…、Soによつて行われる。演算器26はこれらの
各周波数に対応した複数系列のきず信号を加減算
あるいは乗除算して相関演算処理をする。即ち、
前記可変移相器221、222,…,22o、帯域
波器231、232,…,23o、及び信号出力
調整器241、242,…,24oなどにおける調
整、並びに位相選択スイツチS1、S2,…,Soの切
替えなどによつて、例えば複数系列のきず信号の
うち、不要雑音信号(例えば無害な傷による擬似
きず信号、あるいは被検査体Aの振動などによる
雑音)を逆相あるいは逆相に近似した入力にし検
出すべき有害なきず信号を同相あるいは同相に近
似した入力にして加算することによつて有害な傷
の信号と不要の雑音信号との識別性を向上させた
り、あるいは、各周波数系列に特有のきず信号を
利用してその位相、振幅などを適宜設定した入力
として加減算あるいは乗除算をして例えば傷の種
類を判別できるような特徴付けした出力を得るこ
とができる。 The output signals of the phase detectors 21 1 , 21 2 , ..., 21 o are transmitted to the bandpass detector 23 whose cutoff frequency is set appropriately.
1 , 23 2 , . . . , 23 o , unnecessary noise is reduced, and the phase of the flaw signal after phase detection is appropriately advanced or delayed according to the set cutoff frequency. Bandwidth wave generators 23 1 , 23 2 ,..., 23 o
The outputs of the signal output regulators 24 1 , 24 2 , ..., 24
After setting the input ratio to the calculator 26 by o ,
A certain signal is passed through the inverting amplifiers 25 1 , 25 2 ,..., 25 o
The phase is inverted by 180° at
5 1 , 25 2 , . . . , 25 o are inputted to the arithmetic unit 26 without going through them. This operation is performed using switches S 1 , S 2 , and
..., carried out by S o . The arithmetic unit 26 performs correlation calculation processing by adding, subtracting, multiplying, and dividing the plurality of series of flaw signals corresponding to each of these frequencies. That is,
Adjustments in the variable phase shifters 22 1 , 22 2 , ..., 22 o , bandpass filters 23 1 , 23 2 , ..., 23 o and signal output adjusters 24 1 , 24 2 , ..., 24 o , and the like; For example, by switching the phase selection switches S 1 , S 2 , ..., S o , unnecessary noise signals (for example, pseudo flaw signals due to harmless flaws, or vibrations of the object A to be inspected, etc.) are detected among multiple series of flaw signals. Distinguish between harmful flaw signals and unnecessary noise signals by inputting the harmful flaw signal to be detected by inputting it in phase or close to the same phase and adding it to the input signal (noise generated by Or, by using the flaw signal specific to each frequency series and adding/subtracting or multiplying/dividing the phase, amplitude, etc. as input, it is possible to distinguish the type of flaw, for example. You can get the output.
このような複数系列のきず信号が相関演算され
た演算器出力はリジヨクシヨン増幅器27で背景
雑音を抑制され、記録増幅器29を経て記録計3
0に記録される。 The output of the arithmetic unit obtained by correlating multiple series of flaw signals has background noise suppressed by the repositioning amplifier 27, and is sent to the recorder 3 via the recording amplifier 29.
Recorded as 0.
本考案による渦流探傷装置は以上説明したよう
に、複数の異る周波数によつて渦流探傷コイルの
励磁コイルを駆動して同時的に各周波数ごとに対
応した複数系列の探傷信号を得、これらの複数系
列の探傷信号に基いて相関演算を行うようにした
ので、有害なきず信号と不要雑音との識別性を向
上させることができ、複数種の傷の識別を容易に
行うことができる。 As explained above, the eddy current flaw detection device according to the present invention drives the excitation coil of the eddy current flaw detection coil using a plurality of different frequencies, simultaneously obtains multiple series of flaw detection signals corresponding to each frequency, and Since the correlation calculation is performed based on multiple series of flaw detection signals, it is possible to improve the discrimination between harmful flaw signals and unnecessary noise, and it is possible to easily identify multiple types of flaws.
第1図は本考案の一実施例を示すブロツク図、
第2図は本考案の他の実施例を示すブロツク図で
ある。
10……高周波発振器、11……混合器、14
……励磁コイル、A……被検査体、15……検出
コイル、16……差動増幅器、17……打消し電
圧発生器、18……緩衝用抵抗器、19……同調
増幅器、20……探傷感度調整器、21……位相
検波器、22……可変移相器、23……帯域波
器、24……信号出力調整器、25……反転増幅
器、26……演算器、27……リジエクシヨン増
幅器、28……リジエクシヨン動作設定器、29
……記録増幅器、30……記録計。
FIG. 1 is a block diagram showing an embodiment of the present invention.
FIG. 2 is a block diagram showing another embodiment of the present invention. 10... High frequency oscillator, 11... Mixer, 14
... Excitation coil, A ... Test object, 15 ... Detection coil, 16 ... Differential amplifier, 17 ... Cancellation voltage generator, 18 ... Buffer resistor, 19 ... Tuning amplifier, 20 ... ...Flaw detection sensitivity adjuster, 21...Phase detector, 22...Variable phase shifter, 23...Bandwidth wave generator, 24...Signal output adjuster, 25...Inverting amplifier, 26...Arithmetic unit, 27... ... Resiexion amplifier, 28 ... Resiexion operation setting device, 29
...recording amplifier, 30...recorder.
Claims (1)
複数の高周波発振器と; 前記複数の高周波発振器からの前記各正弦波信
号を混合する混合器と; 帰還ループに出力電流制御のための電流−電圧
変換用抵抗器を備え、前記混合器の出力を定電流
増幅する定電流電力増幅器と; 前記定電流電力増幅器の出力を受けて励磁され
る一次側励磁コイルと; 前記一次側励磁コイルとの間に被検査体が配置
され得る間隔で一次側励磁コイルに対向して設け
られて、一次側励磁コイルによる交番磁界によつ
て誘起電圧信号を生じる二次側検出コイルと; 前記各高周波発振器にそれぞれ対応して設けら
れ、被検査体の正常部における前記二次側検出コ
イルからの各高周波発振器の周波数に対応した誘
起電圧をそれぞれ打消すための、各高周波発振器
に対応した打消し平衡用基準電圧信号を出力する
複数の打消し電圧発生器と; 前記打消し電圧発生器にそれぞれ対応して設け
られ、一方の各入力端子に前記二次側検出コイル
からの誘起電圧信号を受け、他方の各入力端子に
前記対応した各打消し電圧発生器からの打消し平
衡用基準電圧信号を受けて、両入力信号の不平衡
出力信号を生じる複数の差動増幅器と; 前記各差動増幅器にそれぞれ対応して設けら
れ、各差動増幅器からの不平衡出力信号を増幅す
る複数の同調増幅器と; 前記各同調増幅器にそれぞれ対応して設けら
れ、各同調増幅器の出力信号の振幅をそれぞれ調
整する複数の探傷感度調節器と; 前記各高周波発振器にそれぞれ対応して設けら
れ、それぞれ前記各高周波発振器の出力信号を受
けて位相検波用参照信号を出力する複数の可変移
相器と; 前記各探傷感度調整器にそれぞれ対応して設け
られ、前記各探傷感度調整器の出力信号を、それ
ぞれ対応する前記各可変移相器からの位相検波用
参照信号に基づいて位相検波して、前記各周波数
に対応した複数のきず信号をそれぞれ出力する複
数の位相検波器と; 前記各位相検波器からのきず信号出力を調整し
て相関演算処理を行なう演算器とを備えた渦流探
傷装置。[Claims for Utility Model Registration] A plurality of high-frequency oscillators that output sine wave signals of different frequencies; a mixer that mixes the respective sine wave signals from the plurality of high-frequency oscillators; and a feedback loop that controls output current. a constant current power amplifier that includes a current-voltage conversion resistor for constant current amplification of the output of the mixer; a primary excitation coil that is excited in response to the output of the constant current power amplifier; a secondary detection coil that is provided opposite to the primary excitation coil at a distance that allows the object to be inspected to be placed between the excitation coil and generates an induced voltage signal by an alternating magnetic field from the primary excitation coil; Cancellation corresponding to each high-frequency oscillator is provided to cancel the induced voltage corresponding to the frequency of each high-frequency oscillator from the secondary side detection coil in the normal part of the object to be inspected. a plurality of canceling voltage generators that output balancing reference voltage signals; and a plurality of canceling voltage generators that are provided corresponding to the canceling voltage generators, and each input terminal of which receives an induced voltage signal from the secondary detection coil. a plurality of differential amplifiers that receive at their other input terminals a reference voltage signal for cancellation balance from each of the corresponding cancellation voltage generators, and generate an unbalanced output signal of both input signals; a plurality of tuned amplifiers, each of which is provided corresponding to the differential amplifier, and amplifies the unbalanced output signal from each differential amplifier; a plurality of flaw detection sensitivity adjusters that respectively adjust; a plurality of variable phase shifters that are provided corresponding to each of the high-frequency oscillators and that each receive an output signal of each of the high-frequency oscillators and output a reference signal for phase detection; is provided corresponding to each of the flaw detection sensitivity adjusters, and performs phase detection on the output signal of each of the flaw detection sensitivity adjusters based on a phase detection reference signal from each of the corresponding variable phase shifters. An eddy current flaw detection device comprising: a plurality of phase detectors that respectively output a plurality of flaw signals corresponding to each frequency; and a computing unit that adjusts the flaw signal output from each of the phase detectors and performs correlation calculation processing.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP17117880U JPS6331003Y2 (en) | 1980-11-29 | 1980-11-29 |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP17117880U JPS6331003Y2 (en) | 1980-11-29 | 1980-11-29 |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS5793854U JPS5793854U (en) | 1982-06-09 |
JPS6331003Y2 true JPS6331003Y2 (en) | 1988-08-18 |
Family
ID=29529543
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP17117880U Expired JPS6331003Y2 (en) | 1980-11-29 | 1980-11-29 |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS6331003Y2 (en) |
-
1980
- 1980-11-29 JP JP17117880U patent/JPS6331003Y2/ja not_active Expired
Also Published As
Publication number | Publication date |
---|---|
JPS5793854U (en) | 1982-06-09 |
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