EP0815441A1 - Eddy current sensor and tube testing equipment comprising same - Google Patents

Eddy current sensor and tube testing equipment comprising same

Info

Publication number
EP0815441A1
EP0815441A1 EP97901658A EP97901658A EP0815441A1 EP 0815441 A1 EP0815441 A1 EP 0815441A1 EP 97901658 A EP97901658 A EP 97901658A EP 97901658 A EP97901658 A EP 97901658A EP 0815441 A1 EP0815441 A1 EP 0815441A1
Authority
EP
European Patent Office
Prior art keywords
windings
sensor
reference plane
winding
tube
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.)
Withdrawn
Application number
EP97901658A
Other languages
German (de)
French (fr)
Inventor
Marc Piriou
Jacky Slazak
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Intercontrole SA
Original Assignee
Intercontrole SA
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Intercontrole SA filed Critical Intercontrole SA
Publication of EP0815441A1 publication Critical patent/EP0815441A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/72—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables
    • G01N27/82—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables for investigating the presence of flaws
    • G01N27/90—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables for investigating the presence of flaws using eddy currents
    • G01N27/9013—Arrangements for scanning

Definitions

  • the invention relates to an eddy current sensor using separate transmitter and receiver windings to carry out non-destructive testing of electrically conductive parts.
  • the invention also relates to a tool for non-destructive testing of tubes, this tool comprising at least one eddy current sensor.
  • the sensor according to the invention can be used to carry out non-destructive testing of a part of any shape and size, as soon as the nature of the material or materials constituting this part makes it possible to induce eddy currents therein.
  • a preferred application in no way limitative, relates to the control of the tubes of the steam generators which equip nuclear power plants.
  • the simplest sensors are sensors comprising a single winding used both as a transmitter and as a receiver.
  • the most common sensors are used in differential measurement. These sensors generally use two windings connected in series, both used also as transmitters and as receivers. Because the windings are placed opposite two neighboring regions of the part, any difference in impedance between the two windings reveals the presence of a defect in the material and its extent.
  • the eddy current sensors each winding of which acts both as a transmitter and as a receiver, carry out local measurements which make it possible to establish the mapping of the faults present inside a part to be checked.
  • this type of sensor only detects faults which are present over a limited depth from the surface of the part close to the measurement windings. Thus, in the case of checking the steam generator tubes, certain point sensors only detect faults on the external wall when these have a depth greater than 40% of the thickness of this wall.
  • the main object of the invention is an eddy current sensor of original design, usable for the control of pieces of any shape, in which the transmission and reception functions are provided by separate windings, arranged in such a way that the performance of detection of faults is significantly increased compared to that of existing sensors (for example so as to detect faults on the external wall having a depth limited to about 20% of the thickness of this wall, in the case of the control of the tubes of a steam generator) without the need to have recourse to a subsequent compensation treatment.
  • an eddy current sensor comprising two transmitting windings and at least one receiving winding arranged symmetrically with respect to a reference plane intended to be oriented in a direction substantially normal to a surface of a part to be checked, the emitting windings being arranged on either side of the reference plane and each comprising a median plane substantially parallel to the reference plane and at least one active part which has a shape substantially complementary to that of the surface, and the receiver winding being oriented perpendicular to the reference plane placed between the active parts of the transmitter windings, and comprising a median plane which forms an angle of about 90 ° with the reference plane; characterized in that the two transmitter windings are connected and coils in such a way that they induce opposite magnetic fields in a spatial area containing the receiver winding, so that the latter is not traversed by any electric current when the region of the part to be inspected located opposite the sensor is free from faults.
  • the carrying out of the transmission and reception functions by separate windings and the particular arrangement of these windings makes it possible to significantly increase the resolution or the detection depth of the sensor, while retaining performances comparable to those of existing local detection sensors.
  • each transmitting winding comprises a single active part corresponding to a fraction of the circumference of this winding, the sensor comprising a single receiving winding placed between these active parts. This characteristic makes it possible to control parts of any shape, that is to say both tubes and plates.
  • the subject of the invention is also a tool for non-destructive testing of a tube, capable of being moved inside the latter.
  • This tool comprises a rotary central body which has a longitudinal axis, and two centering rings which support the body in the tube so that the axis of the body is substantially coincident with that of the tube.
  • the rotary central body then supports at least one eddy current sensor as defined previously.
  • the rotary central body supports a first sensor whose reference plane is perpendicular to the longitudinal axis of the body and a second sensor whose reference plane contains the longitudinal axis of the body.
  • the first and second sensors are then mounted on the rotary central body at locations diametrically opposite with respect to the longitudinal axis of the body.
  • FIG. 1 is a perspective view schematically showing a tool equipped with two eddy current sensors according to the invention, capable of being introduced into a steam generator tube, to ensure non-destructive control;
  • FIG. 2 is a sectional view diagrammatically illustrating one of the sensors mounted on the tool of Figure 1, as well as the portion of
  • FIG. 3 is a sectional view along line III-III of Figure 2;
  • FIG. 4 is a sectional view in diagram ⁇ tick comparable to Figure 2 illustrating the second sensor of the tool of Figure 1; and - Figure 5 is a sectional view along line VV of Figure 4.
  • FIG. 1 there is shown in phantom a section of tube T which we want to perform non-destructive testing.
  • This section of tube can in particular be part of a steam generator fitted to a nuclear power plant.
  • the corrosive environment in which the tubes of the steam generators are found imposes regular checks aimed at detecting possible degradations necessitating plugging or repairing the tubes concerned.
  • FIG. 1 there is shown by way of non-limiting example, a tool 10 designed to perform non-destructive testing of the tube T, by means of two eddy current sensors according to the invention.
  • the eddy current sensors in accordance with the invention can be used for any other type of non-destructive testing.
  • these sensors can be used both to carry out the control of a tubular part from the inside thereof, and to carry out the control of parts of any other shape such as flat parts or any profiles, by one or other of the faces of these parts.
  • the non-destructive testing tool 10 illustrated in FIG. 1 has a known overall configuration which is not part of the invention. To facilitate understanding, we simply indicate here the general characteristics of this tool.
  • the non-destructive testing tool 10 has substantially the shape of a cylinder whose longitudinal axis is intended to be substantially coincident with that of the tube T. It comprises a front body 12, in the form of a warhead, facilitating its penetration into the tube T, as well as a rear body 14 by which the tool is connected to an external installation (not shown) through a flexible cable 15.
  • This flexible cable 15 makes it possible to control the movements of the tool 10 in the tube T and transmit between the tools and the external installation the electrical signals necessary for the control.
  • the front body 12 and the rear body 14 are non-rotating elements which both support a flexible centering ring 16, 18 by means of which the tool 10 is centered in the tube T.
  • the non-destructive testing tool 10 comprises a rota ⁇ tif central body 20 centered on the longitudinal axis of the tool and capable of being rotated at speed constant around this axis when the latter moves inside the tube T.
  • the rotation of the central body 20 is controlled by a motor (not shown) housed in the rear body 14.
  • the rotary central body 20 of the tool 10 for non-destructive testing carries two eddy current sensors, designated respectively by the references 22a and 22b. These two sensors 22a and 22b are located on the central body 20 at locations diametrically opposite with respect to the longitudinal axis of the tool. For this reason, the sensor 22b is not visible in FIG. 1.
  • the combined translational and rotational movements of the central part 20 of the tool 10 have the effect of displacing the sensors 22a and 22b according to a helical movement inside the tube T. A scanning of the wall of this- this is thus ensured.
  • the parts 24a and 24b of the central body 20 which surround the sensors 22a and 22b are made of electrically insulating material.
  • the eddy current sensor 22a which equips the tool 10 in Figure 1.
  • this sensor 22a comprises two transmitter windings 26 and a receiver winding 28.
  • the transmitter windings 26 are arranged symmetrically, on either side of a reference plane PI, provided to be oriented perpendicular to the inner surface of the tube T, that is to say in the case of the sensor 22a perpendicular to the axis of the tube T.
  • the reference plane PI constitutes a plane of symmetry for the receiver winding 28.
  • the median planes of the emitting windings 26 are arranged substantially parallel to the reference plane PI on either side of the latter.
  • the median plane of the receiving winding 28 is oriented perpendicular to the reference plane PI.
  • the dimensions of the receiver winding 28 are substantially smaller than those of the transmitter windings 26.
  • each of the emitting windings 26 comprises an active part 26a, which corresponds to a fraction of the circumference of this winding and has a shape complementary to that of the interior surface of the tube T. Because the median planes of the emitting windings 26 are parallel to the reference plane PI which is oriented perpendicular to the axis of the tube T, these active parts 26a of the emitting windings 26 therefore have in this case an arc shape. Over the rest of the circumference of the emitting windings, these can take any shape.
  • the receiver bearing 28 is placed between the active parts 26a of the transmitter windings 26.
  • the transmitter windings 26 are electrically connected in series so as to be supplied simultaneously by the same alternating electric current of any shape (sinusoidal, pulse or other).
  • the primary magnetic fields thus generated by the two emitting windings 26 create field lines L1, L2, part of which travels in the wall of the tube T, opposite the active parts 26a of the emitting windings 26.
  • the geometrical configuration which comes from The description of the eddy current sensor 22a according to the invention is such that the receiver winding 28 is at the center of these field lines L1, L2.
  • the electrical connection of the transmitter windings 26 and the direction of their windings are made in such a way that the primary magnetic fields which they generate are oriented in the direction opposite in the spatial zone in which the receiver winding 28 is located. Due to the perfect symmetry of the sensor and the arrangement described above, the receiver winding 28 is therefore not traversed by any electric current as long as the region of the tube T located opposite the sensor is free of faults. The electric current flowing in the receiver winding 28 is therefore directly representative of a fault present in the region of the tube situated opposite the sensor, without it being necessary to carry out any subsequent electrical treatment.
  • the receiver winding 28 is insensitive to the permanent state of the secondary magnetic field created by the eddy currents induced in the primary tube T.
  • the receiver winding 28 therefore only detects variations in the secondary magnetic field which result from the presence of defects in the thickness of the wall of the tube T. More specifically, the orientation of the eddy current sensor 22a illustrated on Figures 2 and 3 can detect cracks which extend mainly along the longitudinal axis of the tube T.
  • the eddy current sensor according to the invention and in particular its insensitivity to the permanent secondary magnetic field allow it to detect faults at a depth substantially greater than the existing eddy current sensors.
  • the sensor according to the invention detects faults up to about 80% of the thickness of the wall of the tube T, while the existing sensors detect such defects only on a depth less than 60% of this thickness.
  • the Fou ⁇ cault 22a current sensor is practically insensitive to cracks oriented along the circumference of the tube T
  • the tool 10 illustrated in FIG. 1 advantageously comprises a second eddy current sensor 22b produced according to the same principle as the sensor 22a but whose orientation is offset by 90 ° relative to the latter.
  • the sensor 22b also comprises two transmitter windings 26 and a receiver winding 28 whose relative arrangement is the same as that of comparable windings of the sensor 22a. More specifically, these three windings 26 and 28 are also arranged symmetrically with respect to a reference plane P2.
  • this reference plane P2 is perpendicular to the reference plane PI of the sensor 22a. More precisely, this reference plane P2 in this case contains the longitudinal axis of the tool.
  • the active parts 26 ′ of these emitting windings are oriented in this case parallel to generators of the tube T. These active parts are therefore rectilinear, as illustrated in particular in Figure 4.
  • the emitting windings 26 of the sensor 22b are electrically connected and coils in a direction such that the primary magnetic fields which they generate when they are excited are oriented in opposite directions in the region of the receiver winding 28.
  • This characteristic illustrated by the field lines L1 and L2 in FIG. 5, makes it possible to obtain an output signal from the receiver winding 28 directly representative of the presence of a defect, without requiring further processing.
  • the senor 22b is sensitive to faults oriented circumferentially in the tube T.
  • the assembly formed by the sensors 22a and 22b therefore makes it possible to detect all the types of faults present in the tube T, on a significantly greater depth than existing sensors and without it being necessary to carry out any processing intended to eliminate a continuous component of the signals delivered by the sensors, since this component does not exist.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Investigating Or Analyzing Materials By The Use Of Magnetic Means (AREA)

Abstract

An eddy current sensor (22a) including two transmitter windings (26) and a receiver winding (28) is provided for non-destructively testing an electrically conductive part (T). The three windings are arranged symmetrically relative to a reference plane (P1) extending perpendicularly to the surface of the part (T). The receiver winding (28) is positioned between the active portions (26a) of the transmitter windings (26) and perpendicular to the plane (P1), whereas the transmitter windings (26) are substantially parallel thereto. The coils and connections of the transmitter windings are such that no current flows through the receiver winding in the absence of a defect. Equipment for testing a tube (T) such as a steam generator tube includes two sensors at right angles to one another.

Description

CAPTEUR A COURANTS DE FOUCAULT ET OUTILLAGE DE CONTROLE DE TUBE COMPORTANT AU MOINS UN TEL CAPTEUR. EDGE CURRENT SENSOR AND TUBE CONTROL TOOLS COMPRISING AT LEAST ONE SUCH SENSOR.
DESCRIPTIONDESCRIPTION
Domaine techniqueTechnical area
L'invention concerne un capteur à courants de Foucault utilisant des enroulements émetteur et récepteur séparés pour effectuer le contrôle non des¬ tructif de pièces électriquement conductrices.The invention relates to an eddy current sensor using separate transmitter and receiver windings to carry out non-destructive testing of electrically conductive parts.
L'invention concerne également un outillage de contrôle non destructif de tubes, cet outillage comprenant au moins un capteur a courants de Foucault.The invention also relates to a tool for non-destructive testing of tubes, this tool comprising at least one eddy current sensor.
Le capteur selon l'invention peut être uti¬ lisé pour effectuer le contrôle non destructif d'une pièce de forme et de dimensions quelconques, dès lors que la nature du ou des matériaux constituant cette pièce permet d'y induire des courants de Foucault. Une application privilégiée, nullement limitative, concerne le contrôle des tubes des générateurs de vapeur qui équipent les centrales nucléaires.The sensor according to the invention can be used to carry out non-destructive testing of a part of any shape and size, as soon as the nature of the material or materials constituting this part makes it possible to induce eddy currents therein. A preferred application, in no way limitative, relates to the control of the tubes of the steam generators which equip nuclear power plants.
Etat de la technique.State of the art.
Compte tenu de leur facilité de mise en oeuvre, les capteurs a courants de Foucault ont fait l'objet de nombreux développements dans le domaine du contrôle non destructif.Given their ease of implementation, eddy current sensors have been the subject of numerous developments in the field of non-destructive testing.
Rappelons que le principe de ces capteurs repose sur la création d'un champ magnétique primaire dans un enroulement alimenté en courant électrique alternatif. Lorsque l'enroulement est placé à proximité d'un matériau électriquement conducteur, ce champ magnétique primaire induit des courants de Foucault dans le matériau. Ces courants de Foucault créent un champ magnétique secondaire opposé au champ magnétique primaire. Le champ magnétique secondaire ainsi créé a pour effet de modifier l'impédance de l'enroulement dans des proportions qui dépendent de la valeur de l'entrefer entre l'enroulement et la pièce et de diffé¬ rents facteurs liés à la forme de la pièce et à sa structure interne. Le contrôle non destructif au moyen des courants de Foucault repose essentiellement sur le fait que la présence de défauts dans le matériau modi¬ fie l'impédance de l'enroulement.Recall that the principle of these sensors is based on the creation of a primary magnetic field in a winding supplied with alternating electric current. When the winding is placed near an electrically conductive material, this field primary magnetic induces eddy currents in the material. These eddy currents create a secondary magnetic field opposite to the primary magnetic field. The secondary magnetic field thus created has the effect of modifying the impedance of the winding in proportions which depend on the value of the air gap between the winding and the part and on various factors related to the shape of the part. and its internal structure. Non-destructive testing using eddy currents is essentially based on the fact that the presence of faults in the material modi¬ fies the impedance of the winding.
Les capteurs les plus simples sont des cap¬ teurs comprenant un enroulement unique utilisé à la fois comme émetteur et comme récepteur.The simplest sensors are sensors comprising a single winding used both as a transmitter and as a receiver.
Les capteurs les plus courants sont utili¬ sés en mesure différentielle. Ces capteurs utilisent généralement deux enroulements montés en série, utili¬ sés l'un et l'autre également comme émetteurs et comme récepteurs. Du fait que les enroulements sont placés en vis-à-vis de deux régions voisines de la pièce, toute différence d'impédance entre les deux enroulements révèle la présence d'un défaut dans le matériau et son étendue. Les capteurs à courants de Foucault dont chaque enroulement agit à la fois comme émetteur et comme récepteur effectuent des mesures locales qui permettent d'établir la cartographie des défauts pré¬ sents à l'intérieur d'une pièce à contrôler. Cependant, ce type de capteurs ne détecte que les défauts qui sont présents sur une profondeur limitée à partir de la surface de la pièce proche des enroulements de mesure. Ainsi, dans le cas du contrôle des tubes des générateurs de vapeur, certains capteurs ponctuels ne détectent des défauts sur la paroi externe que lorsque ceux-ci ont une profondeur supérieure à 40% de l'épais¬ seur de cette paroi.The most common sensors are used in differential measurement. These sensors generally use two windings connected in series, both used also as transmitters and as receivers. Because the windings are placed opposite two neighboring regions of the part, any difference in impedance between the two windings reveals the presence of a defect in the material and its extent. The eddy current sensors, each winding of which acts both as a transmitter and as a receiver, carry out local measurements which make it possible to establish the mapping of the faults present inside a part to be checked. However, this type of sensor only detects faults which are present over a limited depth from the surface of the part close to the measurement windings. Thus, in the case of checking the steam generator tubes, certain point sensors only detect faults on the external wall when these have a depth greater than 40% of the thickness of this wall.
Dans le document EP-A-0 370 691, on a proposé de contrôler un tube au moyen d'un appareil comprenant un seul capteur à courants de Foucault monté coaxialement entre deux pièces d'extrémité. Ce capteur comprend deux enroulements émetteurs disposés autour d'un axe commun prévu pour être placé selon l'axe du tube, et une pluralité d'enroulement récepteurs dispo- ses dans l'intervalle annulaire qui sépare les enroule¬ ments émetteurs, de telle sorte que leurs axes soient orientés radialement par rapport à l'axe des enroule¬ ments émetteurs. Ces derniers sont excités en opposi¬ tion, afin que les champs magnétiques primaires s'ajou- tent dans l'intervalle qui contient les enroulements récepteurs. La détection est effectuée à tour de rôle sur les enroulements récepteurs successifs, afin d'ef¬ fectuer un balayage circonférentiel lors du déplacement de l'appareil dans le tube. Du fait que les champs magnétiques primai¬ res s'ajoutent à l'emplacement des enroulements récep¬ teurs, l'appareil décrit dans ce document nécessite un traitement électronique de compensation afin d'éliminer des signaux émis par les enroulements récepteurs la fraction qui découle de ces champs magnétiques primai¬ res additionnés.In document EP-A-0 370 691, it has been proposed to control a tube by means of an apparatus comprising a single eddy current sensor mounted coaxially between two end pieces. This sensor comprises two transmitter windings arranged around a common axis intended to be placed along the axis of the tube, and a plurality of receiver windings available in the annular interval which separates the transmitter windings, so that their axes are oriented radially with respect to the axis of the transmitter windings. The latter are excited in opposition, so that the primary magnetic fields are added in the interval which contains the receiving windings. The detection is carried out in turn on the successive receiver windings, in order to perform a circumferential scanning during the movement of the device in the tube. Due to the fact that the primary magnetic fields are added to the location of the receiver windings, the device described in this document requires electronic compensation processing in order to eliminate the fraction arising from the signals sent by the receiver windings. of these added primary magnetic fields.
Par ailleurs, l'appareil décrit dans le document EP-A-0 70 691 est pratiquement insensible à des fissures orientées selon la circonférence du tube. Enfin, cet appareil ne peut être utilisé que pour le contrôle d'un tube. Il ne permet donc pas le contrôle de pièces de formes différentes telles que des plaques.Furthermore, the apparatus described in document EP-A-0 70 691 is practically insensitive to cracks oriented along the circumference of the tube. Finally, this device can only be used for checking a tube. It therefore does not allow the control of parts of different shapes such as plates.
Eacposé de l'invention L'invention a principalement pour ob3et un capteur à courants de Foucault de conception originale, utilisable pour le contrôle de pièces de formes quel- conques, dans lequel les fonctions d'émission et de réception sont assurées par des enroulements séparés, agencés de telle sorte que les performances de détec¬ tion des défauts soient sensiblement augmentées par rapport à celles des capteurs existants (par exemple de façon à détecter des défauts sur la paroi externe ayant une profondeur limitée à environ 20 % de l'épaisseur de cette paroi, dans le cas du contrôle des tubes d'un générateur de vapeur) sans qu'il soit nécessaire d'avoir recours à un traitement de compensation ulte- rieur.Summary of the invention The main object of the invention is an eddy current sensor of original design, usable for the control of pieces of any shape, in which the transmission and reception functions are provided by separate windings, arranged in such a way that the performance of detection of faults is significantly increased compared to that of existing sensors (for example so as to detect faults on the external wall having a depth limited to about 20% of the thickness of this wall, in the case of the control of the tubes of a steam generator) without the need to have recourse to a subsequent compensation treatment.
Conformément a l'invention, ce résultat est obtenu au moyen d'un capteur a courants de Foucault, comprenant deux enroulement émetteurs et au moins un enroulement récepteur disposés de façon symétrique par rapport a un plan de référence prévu pour être orienté selon une direction sensiblement normale a une surface d'une pièce à contrôler, les enroulements émetteurs étant disposés de part et d'autre du plan de référence et comprenant chacun un plan médian sensiblement paral- lèle au plan de référence et au moins une partie active qui présente une forme sensiblement complémentaire de celle de la surface, et l'enroulement récepteur étant orienté perpendiculairement au plan de référence placé entre les parties actives des enroulements émetteurs, et comprenant un plan médian qui forme avec le plan de référence un angle d'environ 90° ; caractérisé par le fait que les deux enroulements émetteurs sont connectés et bobines de façon telle qu'ils induisent des champs magnétiques opposés dans une zone spatiale contenant l'enroulement récepteur, de telle sorte que ce dernier n'est parcouru par aucun courant électrique lorsque la région de la pièce a contrôler située en face du capteur est dépourvue de défaut.According to the invention, this result is obtained by means of an eddy current sensor, comprising two transmitting windings and at least one receiving winding arranged symmetrically with respect to a reference plane intended to be oriented in a direction substantially normal to a surface of a part to be checked, the emitting windings being arranged on either side of the reference plane and each comprising a median plane substantially parallel to the reference plane and at least one active part which has a shape substantially complementary to that of the surface, and the receiver winding being oriented perpendicular to the reference plane placed between the active parts of the transmitter windings, and comprising a median plane which forms an angle of about 90 ° with the reference plane; characterized in that the two transmitter windings are connected and coils in such a way that they induce opposite magnetic fields in a spatial area containing the receiver winding, so that the latter is not traversed by any electric current when the region of the part to be inspected located opposite the sensor is free from faults.
Dans le capteur selon l'invention, la réa- lisation des fonctions d'émission et de réception par des enroulements sépares et l'agencement particulier de ces enroulements permet d'augmenter sensiblement la résolution ou la profondeur de détection du capteur, tout en conservant des performances comparables à celles des capteurs de détection locale existants.In the sensor according to the invention, the carrying out of the transmission and reception functions by separate windings and the particular arrangement of these windings makes it possible to significantly increase the resolution or the detection depth of the sensor, while retaining performances comparable to those of existing local detection sensors.
Par ailleurs, du fait que le sens des enroulements émetteurs et la connexion électrique de ces enroulements sont réalises de façon telle que ces enroulements induisent des champs magnétiques primaires opposes a l'emplacement de l'enroulement récepteur, le signal délivré par ce dernier est directement représen¬ tatif de la présence d'un défaut éventuel, sans qu'il soit nécessaire de procéder a un traitement électrique ultérieur de compensation. De préférence, chaque enroulement émetteur comprend une seule partie active correspondant a une fraction de circonférence de cet enroulement, le cap¬ teur comportant un seul enroulement récepteur place entre ces parties actives. Cette caractéristique permet de contrôler des pièces de formes quelconques, c'est-a-dire aussi bien des tubes que des plaques.Furthermore, since the direction of the transmitter windings and the electrical connection of these windings are made in such a way that these windings induce primary magnetic fields opposite to the location of the receiver winding, the signal delivered by the latter is directly representative of the presence of a possible fault, without it being necessary to carry out a subsequent electrical compensation treatment. Preferably, each transmitting winding comprises a single active part corresponding to a fraction of the circumference of this winding, the sensor comprising a single receiving winding placed between these active parts. This characteristic makes it possible to control parts of any shape, that is to say both tubes and plates.
L'invention a aussi pour objet un outillage de contrôle non destructif d'un tube, susceptible d'être déplace a l'intérieur de ce dernier. Cet outillage comprend un corps central rotatif qui pré¬ sente un axe longitudinal, et deux anneaux de centrage qui supportent le corps dans le tube de façon que l'axe du corps soit sensiblement confondu avec celui du tube. Le corps central rotatif supporte alors au moins un capteur à courants de Foucault tel que défini précédem¬ ment .The subject of the invention is also a tool for non-destructive testing of a tube, capable of being moved inside the latter. This tool comprises a rotary central body which has a longitudinal axis, and two centering rings which support the body in the tube so that the axis of the body is substantially coincident with that of the tube. The rotary central body then supports at least one eddy current sensor as defined previously.
Dans une forme de réalisation préféren¬ tielle, qui permet de détecter tout type de défaut dans le tube, sur une grande profondeur, le corps central rotatif supporte un premier capteur dont le plan de référence est perpendiculaire à l'axe longitudinal du corps et un deuxième capteur dont le plan de référence contient l'axe longitudinal du corps. Avantageusement, le premier et le deuxième capteurs sont alors montés sur le corps central rotatif en des emplacements diamétralement opposés par rapport à l'axe longitudinal du corps.In a preferred embodiment, which makes it possible to detect any type of defect in the tube, over a great depth, the rotary central body supports a first sensor whose reference plane is perpendicular to the longitudinal axis of the body and a second sensor whose reference plane contains the longitudinal axis of the body. Advantageously, the first and second sensors are then mounted on the rotary central body at locations diametrically opposite with respect to the longitudinal axis of the body.
Brève description des dessinsBrief description of the drawings
On décrira à présent, à titre d'exemples non limitatifs, différentes formes de réalisation de l'invention, en se référant aux dessins annexés, dans lesquels :We will now describe, by way of nonlimiting examples, various embodiments of the invention, with reference to the accompanying drawings, in which:
- la figure 1 est une vue en perspective représentant de façon schématique un outillage équipé de deux capteurs à courants de Foucault conformes à l'invention, susceptible d'être introduit dans un tube de générateur de vapeur, pour en assurer le contrôle non destructif ;- Figure 1 is a perspective view schematically showing a tool equipped with two eddy current sensors according to the invention, capable of being introduced into a steam generator tube, to ensure non-destructive control;
- la figure 2 est une vue en coupe illus¬ trant schématiquement l'un des capteurs montés sur l'outillage de la figure 1, ainsi que la portion de - Figure 2 is a sectional view diagrammatically illustrating one of the sensors mounted on the tool of Figure 1, as well as the portion of
- la figure 3 est une vue en coupe selon la ligne III-III de la figure 2 ;- Figure 3 is a sectional view along line III-III of Figure 2;
- la figure 4 est une vue en coupe schéma¬ tique comparable à la figure 2 illustrant le deuxième capteur de l'outillage de la figure 1 ; et - la figure 5 est une vue en coupe selon la ligne V-V de la figure 4.- Figure 4 is a sectional view in diagram¬ tick comparable to Figure 2 illustrating the second sensor of the tool of Figure 1; and - Figure 5 is a sectional view along line VV of Figure 4.
E3cposé détaillé de formes de réalisation préférentiel- lesE3 detailed description of preferred embodiments
Sur la figure 1, on a représente en traits mixtes un tronçon de tube T dont on désire effectuer le contrôle non destructif. Ce tronçon de tube peut notam- ment faire partie d'un générateur de vapeur équipant une centrale nucléaire. En effet, l'environnement cor¬ rosif dans lequel se trouvent les tubes des générateurs de vapeur impose des contrôles réguliers visant a détecter d'éventuelles dégradations nécessitant l'obtu- ration ou une réparation des tubes concernés. Du fait que les tubes des générateurs de vapeur ne sont acces¬ sibles que par l'intérieur, leur contrôle non destruc¬ tif s'effectue traditionnellement en déplaçant a l'in¬ térieur de chacun des tubes un outillage de contrôle approprié, d'une manière telle qu'un balayage efficace de la paroi du tube soit effectue.In Figure 1, there is shown in phantom a section of tube T which we want to perform non-destructive testing. This section of tube can in particular be part of a steam generator fitted to a nuclear power plant. In fact, the corrosive environment in which the tubes of the steam generators are found imposes regular checks aimed at detecting possible degradations necessitating plugging or repairing the tubes concerned. Due to the fact that the tubes of the steam generators are only accessible from the inside, their non-destructive control is traditionally carried out by moving suitable control tools inside each of the tubes, in such a way that effective scanning of the wall of the tube is carried out.
Sur la figure 1, on a représente a titre d'exemple nullement limitatif, un outillage 10 conçu pour effectuer le contrôle non destructif du tube T, au moyen de deux capteurs à courants de Foucault conformes à l'invention. On rappellera toutefois que les capteurs à courants de Foucault conformes à l'invention peuvent être utilisés pour tout autre type de contrôle non destructif. Ainsi, ces capteurs peuvent être utilises aussi bien pour effectuer le contrôle d'une pièce tubu¬ laire par l'intérieur de celle-ci, que pour effectuer le contrôle de pièces de toutes autres formes telles que des pièces planes ou de profils quelconques, par l'une ou l'autre des faces de ces pièces. L'outillage 10 de contrôle non destructif illustré sur la figure 1 présente une configuration d'ensemble connue qui ne fait pas partie de l'inven¬ tion. Pour faciliter la compréhension, on indiquera simplement ici les caractéristiques générales de cet outillage.In Figure 1, there is shown by way of non-limiting example, a tool 10 designed to perform non-destructive testing of the tube T, by means of two eddy current sensors according to the invention. It will however be recalled that the eddy current sensors in accordance with the invention can be used for any other type of non-destructive testing. Thus, these sensors can be used both to carry out the control of a tubular part from the inside thereof, and to carry out the control of parts of any other shape such as flat parts or any profiles, by one or other of the faces of these parts. The non-destructive testing tool 10 illustrated in FIG. 1 has a known overall configuration which is not part of the invention. To facilitate understanding, we simply indicate here the general characteristics of this tool.
L'outillage 10 de contrôle non destructif présente sensiblement la forme d'un cylindre dont l'axe longitudinal est prévu pour être sensiblement confondu avec celui du tube T. Il comporte un corps avant 12, en forme d'ogive, facilitant sa pénétration dans le tube T, ainsi qu'un corps arrière 14 par lequel l'outillage est relié à une installation extérieure (non représen¬ tée) au travers d'un câble souple 15. Ce câble souple 15 permet de commander les déplacements de l'outillage 10 dans le tube T et de transmettre entre l'outillage et l'installation extérieure les signaux électriques nécessaires au contrôle.The non-destructive testing tool 10 has substantially the shape of a cylinder whose longitudinal axis is intended to be substantially coincident with that of the tube T. It comprises a front body 12, in the form of a warhead, facilitating its penetration into the tube T, as well as a rear body 14 by which the tool is connected to an external installation (not shown) through a flexible cable 15. This flexible cable 15 makes it possible to control the movements of the tool 10 in the tube T and transmit between the tools and the external installation the electrical signals necessary for the control.
Le corps avant 12 et le corps arrière 14 sont des éléments non rotatifs qui supportent l'un et l'autre un anneau de centrage souple 16, 18 au moyen duquel l'outillage 10 est centré dans le tube T.The front body 12 and the rear body 14 are non-rotating elements which both support a flexible centering ring 16, 18 by means of which the tool 10 is centered in the tube T.
Dans sa partie intermédiaire située entre les anneaux de centrage 16 et 18, l'outillage 10 de contrôle non destructif comporte un corps central rota¬ tif 20 centré sur l'axe longitudinal de l'outillage et susceptible d'être entraîné en rotation à vitesse constante autour de cet axe lors du déplacement de ce dernier à l'intérieur du tube T. La rotation du corps central 20 est commandée par un moteur (non représenté) logé dans le corps arrière 14.In its intermediate part located between the centering rings 16 and 18, the non-destructive testing tool 10 comprises a rota¬ tif central body 20 centered on the longitudinal axis of the tool and capable of being rotated at speed constant around this axis when the latter moves inside the tube T. The rotation of the central body 20 is controlled by a motor (not shown) housed in the rear body 14.
Dans la forme de réalisation représentée à titre d'exemple sur la figure 1, le corps central rota¬ tif 20 de l'outillage 10 de contrôle non destructif porte deux capteurs a courants de Foucault, désignés respectivement par les références 22a et 22b. Ces deux capteurs 22a et 22b sont situes sur le corps central 20 en des emplacements diamétralement opposés par rapport a l'axe longitudinal de l'outillage. Pour cette raison, le capteur 22b n'est pas visible sur la figure 1.In the embodiment shown by way of example in FIG. 1, the rotary central body 20 of the tool 10 for non-destructive testing carries two eddy current sensors, designated respectively by the references 22a and 22b. These two sensors 22a and 22b are located on the central body 20 at locations diametrically opposite with respect to the longitudinal axis of the tool. For this reason, the sensor 22b is not visible in FIG. 1.
Les mouvements de translation et de rota¬ tion combinées de la partie centrale 20 de l'outillage 10 ont pour effet de déplacer les capteurs 22a et 22b selon un mouvement hélicoïdal à l'intérieur du tube T. Un balayage de la paroi de celui-ci est ainsi assuré.The combined translational and rotational movements of the central part 20 of the tool 10 have the effect of displacing the sensors 22a and 22b according to a helical movement inside the tube T. A scanning of the wall of this- this is thus ensured.
Afin d'assurer l'isolation électrique de chacun des capteurs, les parties 24a et 24b du corps central 20 qui entourent les capteurs 22a et 22b sont réalisées en matériau électriquement isolant. On décrira à présent, en se référant aux figures 2 et 3, le capteur a courants de Foucault 22a qui équipe l'outillage 10 sur la figure 1.In order to ensure the electrical insulation of each of the sensors, the parts 24a and 24b of the central body 20 which surround the sensors 22a and 22b are made of electrically insulating material. We will now describe, with reference to Figures 2 and 3, the eddy current sensor 22a which equips the tool 10 in Figure 1.
Comme l'illustrent schématiquement les fi¬ gures 2 et 3, ce capteur 22a comprend deux enroulements émetteurs 26 et un enroulement récepteur 28. Les enroulements émetteurs 26 sont disposés symétriquement, de part et d'autre d'un plan de référence PI, prévu pour être orienté perpendiculairement à la surface intérieure du tube T, c'est-à-dire dans le cas du cap- teur 22a perpendiculairement à l'axe du tube T. De même, le plan de référence PI constitue un plan de symétrie pour l'enroulement récepteur 28.As schematically illustrated in FIGS. 2 and 3, this sensor 22a comprises two transmitter windings 26 and a receiver winding 28. The transmitter windings 26 are arranged symmetrically, on either side of a reference plane PI, provided to be oriented perpendicular to the inner surface of the tube T, that is to say in the case of the sensor 22a perpendicular to the axis of the tube T. Likewise, the reference plane PI constitutes a plane of symmetry for the receiver winding 28.
De façon plus précise, si l'on appelle "plan médian" de chacun des enroulements 26 et 28 le plan qui contient le fil central de cet enroulement, les plans médians des enroulements émetteurs 26 sont disposés sensiblement parallèlement au plan de réfé¬ rence PI de part et d'autre de ce dernier. Par ailleurs, le plan médian de l'enroulement récepteur 28 est orienté perpendiculairement au plan de référence PI. En outre, les dimensions de l'enroulement récepteur 28 sont sensiblement inférieures à celles des enroulements émetteurs 26.More precisely, if the term "median plane" of each of the windings 26 and 28 is called the plane which contains the central wire of this winding, the median planes of the emitting windings 26 are arranged substantially parallel to the reference plane PI on either side of the latter. Furthermore, the median plane of the receiving winding 28 is oriented perpendicular to the reference plane PI. In addition, the dimensions of the receiver winding 28 are substantially smaller than those of the transmitter windings 26.
Comme l'illustre plus précisément la figure 3, chacun des enroulements émetteurs 26 comporte une partie active 26a, qui correspond à une fraction de circonférence de cet enroulement et présente une forme complémentaire de celle de la surface intérieure du tube T. Du fait que les plans médians des enroulements émetteurs 26 sont parallèles au plan de référence PI qui est orienté perpendiculairement à l'axe du tube T, ces parties actives 26a des enroulements émetteurs 26 présentent donc dans ce cas une forme en arc de cercle. Sur le reste de la circonférence des enroulements émet- teurs, ceux-ci peuvent prendre des formes quelconques.As illustrated more precisely in FIG. 3, each of the emitting windings 26 comprises an active part 26a, which corresponds to a fraction of the circumference of this winding and has a shape complementary to that of the interior surface of the tube T. Because the median planes of the emitting windings 26 are parallel to the reference plane PI which is oriented perpendicular to the axis of the tube T, these active parts 26a of the emitting windings 26 therefore have in this case an arc shape. Over the rest of the circumference of the emitting windings, these can take any shape.
Selon un autre aspect de l'invention, l'en¬ roulement récepteur 28 est placé entre les parties actives 26a des enroulements émetteurs 26.According to another aspect of the invention, the receiver bearing 28 is placed between the active parts 26a of the transmitter windings 26.
Les enroulements émetteurs 26 sont connec- tés électriquement en série de façon à être alimentés simultanément par un même courant électrique alternatif de forme quelconque (sinusoïdale, impulsionnelle ou autre) . Les champs magnétiques primaires ainsi engen¬ drés par les deux enroulements émetteurs 26 créent des lignes de champs Ll, L2 dont une partie chemine dans la paroi du tube T, en face des parties actives 26a des enroulements émetteurs 26. La configuration géométrique qui vient d'être décrite du capteur à courants de Foucault 22a conforme à l'invention est telle que l'en- roulement récepteur 28 se trouve au centre de ces lignes de champs Ll, L2.The transmitter windings 26 are electrically connected in series so as to be supplied simultaneously by the same alternating electric current of any shape (sinusoidal, pulse or other). The primary magnetic fields thus generated by the two emitting windings 26 create field lines L1, L2, part of which travels in the wall of the tube T, opposite the active parts 26a of the emitting windings 26. The geometrical configuration which comes from The description of the eddy current sensor 22a according to the invention is such that the receiver winding 28 is at the center of these field lines L1, L2.
En outre, la connexion électrique des enroulements émetteurs 26 et le sens de leurs bobinages sont réalisés de façon telle que les champs magnétiques primaires qu'ils engendrent soient orientés en sens opposés dans la zone spatiale dans laquelle se trouve l'enroulement récepteur 28. Du fait de la symétrie parfaite du capteur et de l'agencement décrit précédem¬ ment, l'enroulement récepteur 28 n'est donc parcouru par aucun courant électrique tant que la région du tube T située en face du capteur est dépourvue de défaut. Le courant électrique qui circule dans l'enroulement récepteur 28 est donc directement représentatif d'un défaut présent dans la région du tube située en face du capteur, sans qu'il soit nécessaire de procéder à un quelconque traitement électrique ultérieur.In addition, the electrical connection of the transmitter windings 26 and the direction of their windings are made in such a way that the primary magnetic fields which they generate are oriented in the direction opposite in the spatial zone in which the receiver winding 28 is located. Due to the perfect symmetry of the sensor and the arrangement described above, the receiver winding 28 is therefore not traversed by any electric current as long as the region of the tube T located opposite the sensor is free of faults. The electric current flowing in the receiver winding 28 is therefore directly representative of a fault present in the region of the tube situated opposite the sensor, without it being necessary to carry out any subsequent electrical treatment.
Il est à noter que ce résultat peut être obtenu soit en bobinant les deux enroulements émetteurs 26 dans le même sens et en les connectant directement en série, soit en les bobinant en sens opposé et en les connectant en opposition, de façon qu'ils soient tou¬ jours excités en sens opposés.It should be noted that this result can be obtained either by winding the two transmitter windings 26 in the same direction and connecting them directly in series, or by winding them in opposite directions and connecting them in opposition, so that they are always excited in opposite directions.
Du fait de cet agencement, l'enroulement récepteur 28 est insensible à l'état permanent du champ magnétique secondaire créé par les courants de Foucault induits dans le tube T primaire. L'enroulement récep¬ teur 28 ne détecte donc que des variations du champ magnétique secondaire qui découlent de la présence de défauts dans l'épaisseur de la paroi du tube T. Plus précisément, l'orientation du capteur à courants de Foucault 22a illustrée sur les figures 2 et 3 permet de détecter des fissures qui s'étendent principalement selon l'axe longitudinal du tube T.Due to this arrangement, the receiver winding 28 is insensitive to the permanent state of the secondary magnetic field created by the eddy currents induced in the primary tube T. The receiver winding 28 therefore only detects variations in the secondary magnetic field which result from the presence of defects in the thickness of the wall of the tube T. More specifically, the orientation of the eddy current sensor 22a illustrated on Figures 2 and 3 can detect cracks which extend mainly along the longitudinal axis of the tube T.
Les caractéristiques particulières du cap- teur à courants de Foucault selon l'invention et notam¬ ment son insensibilité au champ magnétique secondaire permanent lui permettent de détecter des défauts sur une profondeur sensiblement plus grande que les cap¬ teurs à courants de Foucault existants. Ainsi, le cap- teur conforme à l'invention détecte des défauts jusqu'à environ 80 % de l'épaisseur de la paroi du tube T, alors que les capteurs existants ne détectent de tels défauts que sur une profondeur inférieure a 60 % de cette épaisseur. Du fait que le capteur à courants de Fou¬ cault 22a est pratiquement insensible a des fissures orientées selon la circonférence du tube T, l'outillage 10 illustre sur la figure 1 comprend avantageusement un deuxième capteur à courants de Foucault 22b réalisé selon le même principe que le capteur 22a mais dont l'orientation est décalée de 90° par rapport à ce dernier.The particular characteristics of the eddy current sensor according to the invention and in particular its insensitivity to the permanent secondary magnetic field allow it to detect faults at a depth substantially greater than the existing eddy current sensors. Thus, the sensor according to the invention detects faults up to about 80% of the thickness of the wall of the tube T, while the existing sensors detect such defects only on a depth less than 60% of this thickness. Because the Fou¬ cault 22a current sensor is practically insensitive to cracks oriented along the circumference of the tube T, the tool 10 illustrated in FIG. 1 advantageously comprises a second eddy current sensor 22b produced according to the same principle as the sensor 22a but whose orientation is offset by 90 ° relative to the latter.
Ainsi, comme l'illustrent les figures 4 et 5, le capteur 22b comporte lui aussi deux enroulements émetteurs 26 et un enroulement récepteur 28 dont l'agencement relatif est le même que celui des enrou¬ lements comparables du capteur 22a. Plus précisément, ces trois enroulements 26 et 28 sont également disposés de façon symétrique par rapport à un plan de référence P2. Toutefois, ce plan de référence P2 est perpendicu¬ laire au plan de référence PI du capteur 22a. De façon plus précise, ce plan de référence P2 contient dans ce cas l'axe longitudinal de l'outillage.Thus, as illustrated in FIGS. 4 and 5, the sensor 22b also comprises two transmitter windings 26 and a receiver winding 28 whose relative arrangement is the same as that of comparable windings of the sensor 22a. More specifically, these three windings 26 and 28 are also arranged symmetrically with respect to a reference plane P2. However, this reference plane P2 is perpendicular to the reference plane PI of the sensor 22a. More precisely, this reference plane P2 in this case contains the longitudinal axis of the tool.
Du fait que les plans médians des enroule- ments émetteurs 26 sont parallèles au plan de référence P2, les parties actives 26'a de ces enroulements émet¬ teurs sont orientées dans ce cas parallèlement à des génératrices du tube T. Ces parties actives sont donc rectilignes, comme l'illustre en particulier la figure 4.Due to the fact that the median planes of the emitting windings 26 are parallel to the reference plane P2, the active parts 26 ′ of these emitting windings are oriented in this case parallel to generators of the tube T. These active parts are therefore rectilinear, as illustrated in particular in Figure 4.
Comme dans le cas du capteur 22a, les enroulements émetteurs 26 du capteur 22b sont connectes électriquement et bobines dans un sens tel que les champs magnétiques primaires qu'ils engendrent lorsqu'ils sont excites sont orientes en sens inverse dans la région de l'enroulement récepteur 28. Cette caractéristique, illustrée par les lignes de champ Ll et L2 sur la figure 5, permet d'obtenir un signal de sortie de l'enroulement récepteur 28 directement repré- sentatif de la présence d'un défaut, sans nécessiter de traitement ultérieur.As in the case of the sensor 22a, the emitting windings 26 of the sensor 22b are electrically connected and coils in a direction such that the primary magnetic fields which they generate when they are excited are oriented in opposite directions in the region of the receiver winding 28. This characteristic, illustrated by the field lines L1 and L2 in FIG. 5, makes it possible to obtain an output signal from the receiver winding 28 directly representative of the presence of a defect, without requiring further processing.
Du fait de son orientation, le capteur 22b est sensible à des défauts orientés circonférentielle¬ ment dans le tube T. L'ensemble formé par les capteurs 22a et 22b permet donc de détecter tous les types de défauts présents dans le tube T, sur une profondeur sensiblement plus élevée que les capteurs existants et sans qu'il soit nécessaire de procéder à un traitement quelconque destiné à éliminer une composante continue des signaux délivrés par les capteurs, puisque cette composante n'existe pas. Because of its orientation, the sensor 22b is sensitive to faults oriented circumferentially in the tube T. The assembly formed by the sensors 22a and 22b therefore makes it possible to detect all the types of faults present in the tube T, on a significantly greater depth than existing sensors and without it being necessary to carry out any processing intended to eliminate a continuous component of the signals delivered by the sensors, since this component does not exist.

Claims

REVENDICATIONS
1. Capteur à courants de Foucault, compre¬ nant deux enroulements émetteurs (26) et au moins un enroulement récepteur (28) disposés de façon symétrique par rapport à un plan de référence (P1,P2) prévu pour être orienté selon une direction sensiblement normale à une surface d'une pièce à contrôler, les enroulements émetteurs (26) étant disposés de part et d'autre du plan de référence (PI, P2) et comprenant chacun un plan médian sensiblement parallèle au plan de référence et au moins une partie active qui présente une forme sen¬ siblement complémentaire de celle de la surface, et l'enroulement récepteur (28) étant orienté perpendicu- lairement au plan de référence (P1,P2) et placé entre les parties actives (26a) des enroulements émetteurs, et comprenant un plan médian qui forme avec le plan de référence un angle d'environ 90° ; caractérisé par le fait que les deux enroulements émetteurs (26) sont connectés et bobinés de façon telle qu'ils induisent des champs magnétiques opposés dans une zone spatiale contenant l'enroulement récepteur (28), de telle sorte que ce dernier n'est parcouru par aucun courant élec¬ trique lorsque la région de la pièce à contrôler située en face du capteur est dépourvue de défaut.1. Eddy current sensor, comprising two transmitting windings (26) and at least one receiving winding (28) arranged symmetrically with respect to a reference plane (P1, P2) intended to be oriented in a substantially direction normal to a surface of a part to be checked, the emitting windings (26) being arranged on either side of the reference plane (PI, P2) and each comprising a median plane substantially parallel to the reference plane and at least one active part which has a shape substantially complementary to that of the surface, and the receiving winding (28) being oriented perpendicular to the reference plane (P1, P2) and placed between the active parts (26a) of the emitting windings , and comprising a median plane which forms an angle of approximately 90 ° with the reference plane; characterized in that the two transmitter windings (26) are connected and wound in such a way that they induce opposite magnetic fields in a spatial area containing the receiver winding (28), so that the latter is not traversed by no electric current when the region of the part to be inspected situated opposite the sensor is free from faults.
2. Capteur selon la revendication 1, carac¬ térisé par le fait que chaque enroulement émetteur (26) comprend une seule partie active correspondant à une fraction de circonférence de cet enroulement, le cap- teur comportant un seul enroulement récepteur (28) placé entre ces parties actives.2. Sensor according to claim 1, charac¬ terized in that each transmitter winding (26) comprises a single active part corresponding to a fraction of the circumference of this winding, the sensor comprising a single receiver winding (28) placed between these active parts.
3. Outillage (10) de contrôle non destruc¬ tif d'un tube (T) , susceptible d'être déplacé à l'inté¬ rieur de ce dernier et comprenant un corps central rotatif (20) présentant un axe longitudinal et deux anneaux de centrage (16,18) supportant le corps dans le tube de façon que 1 ' axe du corps soit sensiblement confondu avec celui du tube, caractérisé par le fait que le corps central rotatif (20) supporte au moins un capteur (22a, 22b) a courants de Foucault selon l'une quelconque des revendications précédentes.3. Tool (10) for non-destructive testing of a tube (T), capable of being moved inside the latter and comprising a rotary central body (20) having a longitudinal axis and two centering rings (16,18) supporting the body in the tube so that the axis of the body is substantially coincident with that of the tube, characterized in that the rotary central body (20) supports at least one sensor (22a, 22b) with eddy currents according to any one of the preceding claims.
4. Outillage selon la revendication 3, ca¬ ractérise par le fait que le corps central rotatif (20) supporte un premier capteur (22a) dont le plan de référence (PI) est perpendiculaire à l'axe longitudinal du corps et un deuxième capteur (22b) dont le plan de référence (P2) contient l'axe longitudinal du corps.4. Tool according to claim 3, ca¬ characterized by the fact that the rotary central body (20) supports a first sensor (22a) whose reference plane (PI) is perpendicular to the longitudinal axis of the body and a second sensor (22b) whose reference plane (P2) contains the longitudinal axis of the body.
5. Outillage selon la revendication 4, ca¬ ractérisé par le fait que le premier et le deuxième capteurs (22a, 22b) sont montés sur le corps central «rotatif (20) en des emplacements diamétralement opposés par rapport à l'axe longitudinal du corps. 5. Tool according to claim 4, ca¬ characterized in that the first and second sensors (22a, 22b) are mounted on the central body "rotary (20) in diametrically opposite locations relative to the longitudinal axis of the body.
EP97901658A 1996-01-24 1997-01-23 Eddy current sensor and tube testing equipment comprising same Withdrawn EP0815441A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
FR9600790A FR2743890B1 (en) 1996-01-24 1996-01-24 EDGE CURRENT SENSOR AND TUBE CONTROL TOOLS COMPRISING AT LEAST ONE SUCH SENSOR
FR9600790 1996-01-24
PCT/FR1997/000133 WO1997027476A1 (en) 1996-01-24 1997-01-23 Eddy current sensor and tube testing equipment comprising same

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EP0815441A1 true EP0815441A1 (en) 1998-01-07

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EP (1) EP0815441A1 (en)
JP (1) JPH11502938A (en)
CA (1) CA2214773A1 (en)
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WO (1) WO1997027476A1 (en)

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JPH11502938A (en) 1999-03-09
WO1997027476A1 (en) 1997-07-31
FR2743890B1 (en) 1998-04-03
CA2214773A1 (en) 1997-07-31
US5914595A (en) 1999-06-22
FR2743890A1 (en) 1997-07-25

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