JPH08226913A - Eddy-current flaw detector - Google Patents
Eddy-current flaw detectorInfo
- Publication number
- JPH08226913A JPH08226913A JP7031978A JP3197895A JPH08226913A JP H08226913 A JPH08226913 A JP H08226913A JP 7031978 A JP7031978 A JP 7031978A JP 3197895 A JP3197895 A JP 3197895A JP H08226913 A JPH08226913 A JP H08226913A
- Authority
- JP
- Japan
- Prior art keywords
- flaw detector
- face
- eddy current
- detection coil
- measured
- 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.)
- Granted
Links
Landscapes
- Investigating Or Analyzing Materials By The Use Of Magnetic Means (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は渦電流探傷装置に関し、
原子力設備や産業機械などの非破壊検査を行う場合に適
用して有用なものである。BACKGROUND OF THE INVENTION The present invention relates to an eddy current flaw detector,
It is useful when applied to non-destructive inspection of nuclear facilities and industrial machinery.
【０００２】[0002]
【従来の技術】一般に、渦電流探傷法による欠陥検出
は、被測定体に接近させた検出コイルに交流電流を流
し、欠陥の存在に伴う被測定体内の誘導電流（渦電流）
の変化を検出コイルのインダクタンス変化として検出す
ることによって行う。2. Description of the Related Art Generally, in the defect detection by the eddy current flaw detection method, an alternating current is passed through a detection coil which is brought close to the object to be measured, and an induced current (eddy current) in the object to be measured due to the existence of the defect.
Is detected as a change in the inductance of the detection coil.
【０００３】図４は、かかる渦電流探傷装置の検出部の
一例を示す断面図である。同図に示すように、本渦電流
探傷装置の検出部２２は、帯板状１にばね板２の基端部
を固定し、このばね板２に、コイルケース３と共に検出
コイル４を固定して構成されている（詳細後述）。なお
図４中の２４は検出コイル４によって生起した磁力線で
ある。FIG. 4 is a cross-sectional view showing an example of a detecting portion of such an eddy current flaw detector. As shown in the figure, the detection unit 22 of the present eddy current flaw detector has a base plate 1 having a base end of a spring plate 2 fixed thereto, and a coil case 3 and a detection coil 4 fixed to the spring plate 2. Is configured (details will be described later). In addition, 24 in FIG. 4 is a magnetic force line generated by the detection coil 4.
【０００４】従って上記構成の検出部２２を有する渦電
流探傷装置によれば、例えば二重管の外管の欠陥を検出
する場合には、図４に示すように、金属製の二重管１３
の外管６と内管５との隙間１０に検出部２２を挿入し、
検出コイル４を外管６に摺動させながら、軸方向及び円
周方向に走査することにより、外管６に生起した欠陥９
の位置と大きさを検出する。Therefore, according to the eddy current flaw detector having the detecting section 22 having the above structure, for example, when a defect of the outer tube of the double tube is detected, as shown in FIG.
Insert the detection unit 22 into the gap 10 between the outer pipe 6 and the inner pipe 5 of
By sliding the detection coil 4 on the outer tube 6 and scanning in the axial direction and the circumferential direction, defects 9 generated on the outer tube 6 are detected.
Detects the position and size of.
【０００５】[0005]
【発明が解決しようとする課題】ところが上記従来技術
に係る渦電流探傷装置では、二重管１３の外管６と内管
５とが必ずしも同心円になっていないことや、二重管１
３の途中に曲管部があることから、隙間１０の間隔が必
ずしも一定ではないため、図４中の矢印で示すようにば
ね板２２と共に検出コイル４が上下に変動し、検出コイ
ル４の図４中下端面と帯状板１との間隔ｄが変化する。
そしてこれが検出コイル４のインダクタンス変化として
検出されるため、実際には欠陥がなくても欠陥があるか
の如く誤った検出信号を出力するという不具合があっ
た。However, in the eddy current flaw detector according to the above-mentioned prior art, the outer tube 6 and the inner tube 5 of the double tube 13 are not necessarily concentric and the double tube 1
Since there is a curved pipe part in the middle of 3, the gap 10 is not always constant, so that the detection coil 4 fluctuates up and down together with the spring plate 22 as shown by the arrow in FIG. 4. The distance d between the middle lower end surface and the strip plate 1 changes.
Since this is detected as a change in the inductance of the detection coil 4, there is a problem that an erroneous detection signal is output as if there is a defect even if there is no defect in reality.
【０００６】従って本発明は上記の点に鑑みてなされた
ものであり、外管６等の被測定体と対向しない検出コイ
ルの一方の端面と、帯状板１等の他の物体との間隔が変
化しても、この物体に影響されることなく正確に被測定
体の欠陥を検出することができる渦電流探傷装置を提供
することを目的とする。Therefore, the present invention has been made in view of the above points, and the distance between one end face of the detection coil that does not face the object to be measured such as the outer tube 6 and another object such as the strip plate 1 is small. It is an object of the present invention to provide an eddy current flaw detector that can accurately detect a defect in a measured object without being affected by this object even if it changes.
【０００７】[0007]
【課題を解決するための手段】上記目的を達成する本発
明の第１の構成は、欠陥の存在に伴う被測定体内の渦電
流の変化を検出コイルにより検出して前記欠陥を検出す
る渦電流探傷装置において、前記検出コイルの前記被測
定体と対向しない一方の端面を覆う強磁性体を設けたこ
とを特徴とする。According to a first aspect of the present invention for achieving the above object, an eddy current for detecting a defect by detecting a change in an eddy current in a body to be measured due to the presence of a defect by a detection coil. In the flaw detection device, a ferromagnetic material is provided to cover one end surface of the detection coil that does not face the measured object.
【０００８】また上記目的を達成する本発明の第２の構
成は、帯状板にばね板を設けると共に該ばね板に検出コ
イルを固定して構成した検出部を有し、欠陥の存在に伴
う被測定体内の渦電流の変化を前記検出コイルにより検
出して前記欠陥を検出する渦電流探傷装置において、前
記検出コイルの前記被測定体と対向しない一方の端面を
覆う強磁性体を設けたことを特徴とする。A second structure of the present invention which achieves the above-mentioned object has a detection part constituted by providing a spring plate on a strip-shaped plate and fixing a detection coil to the spring plate. In the eddy current flaw detector for detecting the defect by detecting the change of the eddy current in the measurement body by the detection coil, a ferromagnetic body is provided to cover one end face of the detection coil that does not face the measured object. Characterize.
【０００９】また上記目的を達成する本発明の第３の構
成は、上記第１又は第２の構成において、強磁性体が強
磁性体箔であることを特徴とする。A third structure of the present invention that achieves the above object is characterized in that, in the first or second structure, the ferromagnetic material is a ferromagnetic foil.
【００１０】[0010]
【作用】上記第１、第２又は第３の構成の本発明によれ
ば、検出コイルの一方の端面側は、強磁性体（強磁性体
箔等）によって磁気シールドされる。このため、前記端
面の近傍に他の物体（帯状板等）がある場合に、この物
体と前記端面との間隔が変化しても、この物体に影響さ
れることなく被測定体の欠陥を正確に検出することがで
きる。According to the first, second or third aspect of the present invention, one end face side of the detection coil is magnetically shielded by a ferromagnetic material (ferromagnetic material foil or the like). Therefore, when there is another object (such as a strip-shaped plate) near the end surface, even if the distance between the object and the end surface changes, the defect of the measured object can be accurately detected without being affected by this object. Can be detected.
【００１１】[0011]
【実施例】以下、本発明の実施例を図面に基づき詳細に
説明する。なお従来技術（図４）と同様の部分には同一
の符号を付した。Embodiments of the present invention will now be described in detail with reference to the drawings. The same parts as those in the prior art (FIG. 4) are designated by the same reference numerals.
【００１２】図１は本発明の実施例に係る渦電流探傷装
置の検出部を一部破断して示す斜視図、図２は図１に示
す渦電流探傷装置の検出部に設けた検出コイルを一部破
断して示す拡大斜視図、図３は図１に示す渦電流探傷装
置の検出部の断面図である。FIG. 1 is a partially cutaway perspective view showing the detection part of the eddy current flaw detector according to the embodiment of the present invention, and FIG. 2 shows a detection coil provided in the detection part of the eddy current flaw detector shown in FIG. FIG. 3 is a partially cutaway enlarged perspective view, and FIG. 3 is a cross-sectional view of a detection unit of the eddy current flaw detector shown in FIG.
【００１３】これらの図に示すように、帯状板１の先端
部には台形状のばね板２が設けられている。このばね板
２は、基端部が帯状板１に固定されると共に、先端部が
帯状板１との間に所定の間隔を有して図中上下（図３の
矢印参照）に移動可能となっている。ばね板２の中央部
分にはコイルケース３が固定されており、このコイルケ
ース３内に検出コイル４が挿入されている。As shown in these figures, a trapezoidal spring plate 2 is provided at the tip of the strip plate 1. The spring plate 2 has a base end portion fixed to the strip plate 1 and a distal end portion which is movable up and down in the figure (see an arrow in FIG. 3) with a predetermined distance from the strip plate 1. Has become. A coil case 3 is fixed to a central portion of the spring plate 2, and a detection coil 4 is inserted in the coil case 3.
【００１４】そして、この検出コイル４の底面、即ち被
測定体と対向しない一方の端面（図中の下端面）には、
皿状の強磁性体箔７が、前記端面を覆うようにして固定
され磁気シールドしている。検出コイル４と強磁性体箔
７とを固着するには、強磁性体箔７の中心に検出コイル
４を置き、接着材を充填して固着するか、または強磁性
体箔７の底面側からコイルケース３にスポット溶接して
固着する。なお、図１中の８は、検出コイル４に接続さ
れたリード線である。The bottom surface of the detection coil 4, that is, one end surface (the lower end surface in the figure) which does not face the object to be measured,
A dish-shaped ferromagnetic foil 7 is fixed so as to cover the end face and magnetically shields it. To fix the detection coil 4 and the ferromagnetic foil 7 to each other, place the detection coil 4 in the center of the ferromagnetic foil 7 and fix it by filling with an adhesive or from the bottom side of the ferromagnetic foil 7. It is fixed to the coil case 3 by spot welding. In addition, 8 in FIG. 1 is a lead wire connected to the detection coil 4.
【００１５】従って上記構成の検出部１２を有する渦電
流探傷装置によれば、例えば二重管の外管の欠陥を検出
する場合には、図１及び図３に示すように、図示しない
送り機構により、二重管１３の外管６と内管５との隙間
１０に検出部１２を挿入し、検出コイル４の図中上端面
側を外管６に摺動させながら、軸方向及び円周方向に走
査することにより、外管６に生起した欠陥９の位置と大
きさを検出する。Therefore, according to the eddy current flaw detector having the detecting section 12 having the above-mentioned structure, for example, when a defect of the outer tube of the double tube is detected, as shown in FIGS. Thus, the detection unit 12 is inserted into the gap 10 between the outer pipe 6 and the inner pipe 5 of the double pipe 13, and the upper end surface side of the detection coil 4 in the figure is slid to the outer pipe 6 while the axial direction and the circumference are By scanning in the direction, the position and size of the defect 9 occurring in the outer tube 6 are detected.
【００１６】そしてこのとき、検出コイル４によって生
起する磁力線１１は、図３に示すように、強磁性体箔７
によって磁気シールドされているため、図中下方には分
布せず、図中上方の測定対象である外管６の方にのみ分
布する。従って隙間１０の間隔が変化し、これに伴って
ばね板２と共に検出コイル４が図中上下に移動して、検
出コイル４の底面と帯状板１との間隔ｄが変化しても、
帯状板１の影響を受けることなく、欠陥９による磁界の
変化のみを検出するため正確な検出データが得られ、正
確に欠陥９を検出することができる。At this time, the magnetic force lines 11 generated by the detection coil 4 are, as shown in FIG.
Since it is magnetically shielded by, it is not distributed in the lower part in the figure, but is distributed only in the outer tube 6 which is the measurement object in the upper part in the figure. Therefore, even if the interval of the gap 10 changes and the detection coil 4 moves up and down in the figure along with the spring plate 2 accordingly, the interval d between the bottom surface of the detection coil 4 and the strip plate 1 also changes.
Since only the change in the magnetic field due to the defect 9 is detected without being affected by the strip plate 1, accurate detection data can be obtained and the defect 9 can be detected accurately.
【００１７】また磁気シールドに強磁性体箔を用いたた
め、検出部１２の厚みを薄くすることができる。更には
検出コイル４と帯状板１との間隔ｄの変化を考慮する必
要がないため、検出部１２を隙間１０に挿入して走査す
るときのスピードアップを計ることができ、検出効率が
向上する。Further, since the ferromagnetic foil is used for the magnetic shield, the thickness of the detecting portion 12 can be reduced. Furthermore, since it is not necessary to consider the change in the distance d between the detection coil 4 and the strip plate 1, it is possible to speed up the scanning when the detection unit 12 is inserted into the gap 10 and the detection efficiency is improved. .
【００１８】[0018]
【発明の効果】以上実施例と共に具体的に説明したよう
に本発明によれば、検出コイルの一方の端面側に強磁性
体（強磁性体箔等）を設けて磁気シールドしたため、前
記端面の近傍に他の物体（帯状板等）がある場合に、こ
の物体と前記端面との間隔が変化しても、この物体に影
響されることなく被測定体の欠陥を正確に検出すること
ができる。しかも前記間隔の変化を考慮する必要がない
ため、検出部を移動して走査する際のスピードアップを
計ることができ、検査効率が向上する。また磁気シール
ドに強磁性体箔を用いたため、検出部の厚みを薄くする
ことができる。According to the present invention as specifically described in connection with the above embodiments, a ferromagnetic material (ferromagnetic material foil or the like) is provided on one end face side of the detection coil to magnetically shield the end face. When there is another object (strip plate, etc.) in the vicinity, even if the distance between this object and the end face changes, the defect of the measured object can be accurately detected without being affected by this object. . In addition, since it is not necessary to consider the change in the interval, it is possible to speed up the scanning operation by moving the detection unit and improve the inspection efficiency. In addition, since the ferromagnetic foil is used for the magnetic shield, the thickness of the detecting portion can be reduced.
【図１】本発明の実施例に係る渦電流探傷装置の検出部
を一部破断して示す斜視図である。FIG. 1 is a partially cutaway perspective view showing a detection unit of an eddy current flaw detector according to an embodiment of the present invention.
【図２】図１に示す渦電流探傷装置の検出部に設けた検
出コイルを一部破断して示す拡大斜視図である。FIG. 2 is an enlarged perspective view showing a partially broken view of a detection coil provided in a detection unit of the eddy current flaw detector shown in FIG.
【図３】図１に示す渦電流探傷装置の検出部の断面図で
ある。3 is a cross-sectional view of a detection unit of the eddy current flaw detector shown in FIG.
【図４】従来技術に係る渦電流探傷装置の検出部の一例
を示す断面図である。FIG. 4 is a sectional view showing an example of a detection unit of an eddy current flaw detector according to a conventional technique.
１ 帯状板 ２ ばね板 ３ コイルケース ４ 検出コイル ５ 内管 ６ 外管 ７ 強磁性体箔 ８ リード線 ９ 欠陥 １０ 隙間 １１ 磁力線 １２ 検出部 １３ 二重管 ｄ 間隔 1 Strip-shaped plate 2 Spring plate 3 Coil case 4 Detection coil 5 Inner tube 6 Outer tube 7 Ferromagnetic foil 8 Lead wire 9 Defect 10 Gap 11 Magnetic field line 12 Detection section 13 Double tube d Interval
Claims (3)
変化を検出コイルにより検出して前記欠陥を検出する渦
電流探傷装置において、 前記検出コイルの前記被測定体と対向しない一方の端面
を覆う強磁性体を設けたことを特徴とする渦電流探傷装
置。1. An eddy current flaw detector for detecting a change in an eddy current in a body to be measured due to the presence of a defect by a detection coil to detect the defect, wherein one end face of the detection coil that does not face the body to be measured. An eddy current flaw detector characterized in that a ferromagnetic material is provided to cover the eddy current.
に検出コイルを固定して構成した検出部を有し、欠陥の
存在に伴う被測定体内の渦電流の変化を前記検出コイル
により検出して前記欠陥を検出する渦電流探傷装置にお
いて、 前記検出コイルの前記被測定体と対向しない一方の端面
を覆う強磁性体を設けたことを特徴とする渦電流探傷装
置。2. A detection part configured by providing a spring plate on a strip-shaped plate and fixing a detection coil to the spring plate, and detecting a change in eddy current in the body to be measured due to the presence of a defect by the detection coil. In the eddy current flaw detector for detecting the defect, a ferromagnetic body is provided to cover one end face of the detection coil that does not face the object to be measured.
置において、 強磁性体が強磁性体箔であることを特徴とする渦電流探
傷装置。3. The eddy current flaw detector according to claim 1 or 2, wherein the ferromagnetic material is a ferromagnetic foil.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP07031978A JP3132971B2 (en) | 1995-02-21 | 1995-02-21 | Eddy current flaw detector |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP07031978A JP3132971B2 (en) | 1995-02-21 | 1995-02-21 | Eddy current flaw detector |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH08226913A true JPH08226913A (en) | 1996-09-03 |
| JP3132971B2 JP3132971B2 (en) | 2001-02-05 |
Family
ID=12346040
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP07031978A Expired - Fee Related JP3132971B2 (en) | 1995-02-21 | 1995-02-21 | Eddy current flaw detector |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3132971B2 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010223938A (en) * | 2009-02-27 | 2010-10-07 | Sekisui Chem Co Ltd | Flaw sensor for water pipe and device for diagnosing degree of decrepitude of water pipe |
| JP2011117872A (en) * | 2009-12-04 | 2011-06-16 | Toshiba Corp | Eddy current flaw detection probe, and eddy current flaw detection testing apparatus using the same |
| JP2013137318A (en) * | 2013-02-12 | 2013-07-11 | Toshiba Corp | Eddy current flaw detection probe and eddy current flaw detection testing device using the same |
| JP2016161489A (en) * | 2015-03-04 | 2016-09-05 | 三菱重工業株式会社 | Nozzle inspection apparatus |
-
1995
- 1995-02-21 JP JP07031978A patent/JP3132971B2/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010223938A (en) * | 2009-02-27 | 2010-10-07 | Sekisui Chem Co Ltd | Flaw sensor for water pipe and device for diagnosing degree of decrepitude of water pipe |
| JP2011117872A (en) * | 2009-12-04 | 2011-06-16 | Toshiba Corp | Eddy current flaw detection probe, and eddy current flaw detection testing apparatus using the same |
| JP2013137318A (en) * | 2013-02-12 | 2013-07-11 | Toshiba Corp | Eddy current flaw detection probe and eddy current flaw detection testing device using the same |
| JP2016161489A (en) * | 2015-03-04 | 2016-09-05 | 三菱重工業株式会社 | Nozzle inspection apparatus |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3132971B2 (en) | 2001-02-05 |
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