Inspection device for inspecting weld seams of hollow longitudinal tubular elements

Abstract

The present invention relates to an inspection device (10) for inspecting welds of hollow longitudinal tubular elements, comprising: a base frame (12), an attachment and locking system (14) for attaching and locking the base frame to the tubular element, a movable device (19) connected to the base frame (12) and rotatable relative to the base frame (12) around the tubular element, a rotation drive device (20) for driving the movable device (19) to rotate relative to the base frame (12), a support member (29) comprising at least one Foucault current sensor unit (24) connected to the movable device (19), the support member (29) being longitudinally translatable relative to the movable device (19), and a longitudinal translation drive device (26) for driving the support member (29) to longitudinally translate.

Description

Technical Field

[0001] According to a first aspect, the invention relates to an inspection device for inspecting a weld seam of a hollow longitudinal tubular element.

[0002] More specifically, the present invention relates to an inspection device for externally inspecting a weld seam of a tubular element. Background Art

[0003] For example, the invention relates to a device for checking welds of pipes or pipe lines used to ensure physical measurements (flow rate, pressure) of the primary circuits of nuclear reactors. These pipes, also called "tubings" in English, are present in the reactor building. Their external diameter is very small.

[0004] For example, when replacing a steam generator in a nuclear reactor, the pipes directly connected to the steam generators should be replaced. Therefore, once the steam generators are replaced, the welds of these pipes must be inspected.

[0005] For this purpose, it is known to use radiographic inspection devices for welds by using photographic film and a radioactive source (for example iridium 192). These inspections are long and tedious. This technique also involves extensive handling of the radioactive source. The chemicals used for film development should also be specially handled. In addition, the operating conditions require qualified radiation protection personnel. Finally, this technique does not allow obtaining results in real time. Summary of the invention

[0006] The object of the present invention is to provide an inspection device that allows a precise, reliable, non-destructive, easy and rapid inspection of hollow tubular elements and that is particularly suitable for use in a nuclear environment.

[0007] To this end, the present invention relates to an inspection device of the above type, comprising:

[0008] - bottom frame,

[0009] - an attachment and locking system for attaching and locking said chassis to the tubular element,

[0010] - a movable member connected to the chassis and movable in rotation relative to the chassis around the tubular element,

[0011] - a rotation drive device for driving the movable device to rotate relative to the base frame,

[0012] a support comprising at least one eddy current sensor unit connected to the movable device, the support being movable in longitudinal translation relative to the movable device,

[0013] - A longitudinal translation driving device, which is used to drive the support member to translate longitudinally.

[0014] This device allows to reduce the duration of the inspection and the real-time interpretation of the results. The manipulation of chemicals and radioactive sources is avoided, which significantly reduces the risks associated with the inspection operation. Finally, the absence of radioactive sources allows collaborative activities at the site where the inspection is carried out.

[0015] According to a particular embodiment, the inspection device comprises one or more of the following features, according to any technically possible combination:

[0016] - the movable means comprises a cylindrical sleeve adapted to surround the tubular element;

[0017] - the rotation drive device and / or the longitudinal translation drive device are manual mechanical drives;

[0018] - the rotation drive device of the movable device comprises a gripping device protruding from the chassis and fixed to the driving pinion, and a plurality of pinions cooperating with the driving pinion and the movable device to drive the movable device to rotate relative to the chassis;

[0019] - the movable device is rotatably movable about the tubular element between a plurality of positions, the plurality of positions being between ten and twenty-four;

[0020] - the device further comprises at least one indexing device configured to determine the position of the movable means around the tubular element;

[0021] The longitudinal translation drive device comprises a cylindrical sleeve surrounding the movable member, the cylindrical sleeve defining a circumferential neck, the support comprising a sliding member cooperating with the circumferential neck of the cylindrical sleeve;

[0022] The support is movable in longitudinal translation relative to the movable means between a plurality of positions.

[0023] According to a second aspect, the present invention relates to a method for inspecting a weld seam of a hollow longitudinal tubular element using the above-mentioned inspection device, the method comprising the following steps:

[0024] - attaching and locking the chassis to the tubular element using the attachment and locking device,

[0025] - using the rotary drive means to rotationally displace the movable means at least once into an angular position about the tubular element relative to the chassis and / or to longitudinally displace the support along the tubular element relative to the movable means into a longitudinal position,

[0026] -Measurements are acquired using an eddy current sensor unit.

[0027] According to a particular embodiment, the method according to the invention may comprise the following features:

[0028] For each angular position, the support is displaced in succession in longitudinal translation along the tubular element from a first extreme check position into a plurality of longitudinal positions up to a second extreme check position. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Other features and advantages of the invention will become apparent from a reading of the following description, given by way of example only and with reference to the accompanying drawings, in which:

[0030] [ Figure 1 ] Figure 1 is an overall perspective view of an inspection device according to the present invention.

[0031] [ Figure 2 ] Figure 2 yes Figure 1 A more detailed perspective view of the rotation drive device of the movable device of the inspection device.

[0032] [ Figure 3 ] Figure 3 yes Figure 1 Detailed perspective view of the longitudinal translation drive device of the support member of the inspection device.

[0033] as well as

[0034] [ Figure 4 ] Figure 4 is with Figure 1 Detailed perspective view of the longitudinal translation drive device of the support member of the inspection device cooperating with the rotation drive device of the movable device. DETAILED DESCRIPTION

[0035] The inspection device 10 according to the present invention for inspecting the weld seam of a hollow longitudinal tubular element (not shown) is Figure 1 Shown in.

[0036] Hollow tubular elements are thin-gauge pipes made of austenitic stainless steel, such as are found in reactor buildings of nuclear power plants.

[0037] The outer diameter of the tubular element is for example between 8 mm and 20 mm. The outer diameter of the tubular element is preferably about 9.5 mm. The wall thickness of the tubular element is less than 2 mm and is preferably about 1.65 mm.

[0038] The small dimensions (diameter, thickness) of the tubular elements allow for simultaneous surface inspection as well as volume inspection.

[0039] Typically, both types of inspections, surface and volumetric, are likely to be performed on piping in the reactor building.

[0040] The weld is typically a butt weld between two hollow tubular elements.

[0041] The inspection device 10 comprises a chassis 12 and an attachment and locking system 14 for attaching and locking the chassis 12 to a tubular element. Figure 1 More specific information can be seen in .

[0042] The attachment and locking system 14 is movable between an open position, in which the tubular element is not retained in the inspection device 10 , and a closed position, in which the tubular element is retained in the inspection device 10 .

[0043] The attachment and locking system 14 comprises a holding device 16 and two links 18, each fixed to the holding device 16 at a first end 21 and to the chassis 12 at a second end 22. At the first end 21 of each link 18, the link 18 is rotationally movable about a first rotation axis relative to the holding device 16. At the second end 22 of each link 18, the link 18 is rotationally movable about a second rotation axis substantially parallel to the first rotation axis relative to the chassis 12.

[0044] When the inspection device 10 is fixed to the hollow tubular element, the first and second rotation axes are substantially parallel to the longitudinal direction of the hollow tubular element.

[0045] More specifically, the attachment and locking system 14 includes at least one retaining hook 23, for example two retaining hooks 23, such as Figure 1 The retaining hook is fixed on the base frame 12.

[0046] The retaining hook 23 defines a receiving housing 25 for receiving a tubular element.

[0047] The retaining means 16 each comprise two fixing means 27 which cooperate with the retaining hooks 23 in the closed position.

[0048] Advantageously, each fixing means 27 has a shape complementary to that of the retaining hook 23. Thus, in the closed position, the tubular element is retained in the receiving housing 25 defined by the retaining hook 23 and the fixing means 27 of the retaining means 16.

[0049] Thus, in operation, the attachment and locking system 14 allows the tubular element to be clamped in the inspection device 10 .

[0050] Preferably, the attachment and locking system 14 comprises, for example, at least one removable assembly means (not shown), such as a bolt, in order to secure the retaining means 16 on the chassis 12 .

[0051] The attachment and locking system 14 allows to firmly hold the inspection device 10 on the tubular element and prevents any accidental displacement of the device 10 during the measuring operation. This contributes to improving the reliability and accuracy of the measurements carried out on the tubular element.

[0052] More specifically in Figure 2As can be seen, the inspection device 10 includes a movable device 19 connected to the base frame 12, a rotation drive device 20 for driving the movable device 19 to rotate relative to the base frame 12, a support member 29 including at least one eddy current sensor unit 24 connected to the movable device 19, and a longitudinal translation drive device 26 for driving the longitudinal translation of the support member 29.

[0053] The movable means 19 comprises a cylindrical sleeve 28 adapted to surround the tubular element. When the inspection device 10 is fixed to the tubular element, the cylindrical sleeve 28 extends substantially in the longitudinal direction of the tubular element.

[0054] The cylindrical sleeve 28 is mounted so as to be slidable on the inner face of the retaining hook 23 .

[0055] The movable means 19 is rotatably movable around the tubular element relative to the chassis 12. More specifically, when the inspection device 10 is fixed to the tubular element, the rotation axis of the movable means 19 substantially coincides with the longitudinal axis of the tubular element.

[0056] Advantageously, the movable means 19 is rotationally movable around the tubular element between a plurality of positions. Preferably, the positions are discrete and stable.

[0057] The plurality of positions is for example between ten and twenty-four, for example twenty-one.

[0058] The positions are, for example, regularly distributed at angles around the tube.

[0059] Preferably, the locations are distributed over the entire circumference of the tube.

[0060] As a variant, the positions are distributed over a portion of the circumference of the tube, for example over an angular distance of 180°.

[0061] Thus, as will be seen in more detail in the description, each rotational displacement of the movable means 19 causes a displacement of the support 29 comprising the eddy current sensor unit 24 around the tubular element.

[0062] Preferably, the rotation drive device 20 is a manual mechanical drive device.

[0063] As in Figure 2 As can be seen more specifically in FIG. 1 , the rotary drive device 20 includes, for example, a gripping device 30 protruding from the chassis 12 and fixed to a drive pinion 32. The gripping member 30 is, for example, disposed on a lateral wall 34 of the chassis 12 that allows the user to easily grip ( Figure 1 ).

[0064] The rotary drive device 20 also comprises a plurality of pinions 36 cooperating with the drive pinion 32 and the movable member 19 , more specifically with a toothed ring 38 fixed to the end of the movable member 19 .

[0065] The rotary drive device 20 allows a reliable and precise displacement of the movable device 19. The rotary drive device 20 also ensures good repeatability and good reproducibility of the position of the movable device 19 around the tubular element. Thus, when the movable device 19 occupies the last position of the plurality of positions, an additional displacement of the movable device 19 using the drive device 20 will cause the movable device 19 to be driven accurately again into the first position of the plurality of positions.

[0066] The inspection device 10 advantageously comprises first indexing means (not shown) configured to determine the angular position of the movable means 19 around the tubular element.

[0067] Thus, at any time, the angular position of the movable device 19 around the tubular element is precisely known and indexed to each acquisition of the eddy current sensor unit 24. This ensures an accurate and high quality reconstruction of the circumferential image of the tubular element.

[0068] The support 29 is movable in longitudinal translation relative to the movable device 19 .

[0069] Instead, the support 29 is rotatably connected to the movable means 19 around the tubular element.

[0070] Preferably, the support 29 is translatable relative to the movable means 19 between a plurality of positions.

[0071] The positions are preferably discrete and stable.

[0072] For example, the support 29 may be movable between a first limit check position on the tubular element and a second limit check position on the tubular element.

[0073] The distance between the first limit check position and the second limit check position is between 30 mm and 50 mm.

[0074] Therefore, the support 29 is advantageously moved between a plurality of positions between the first limit checking position and the second limit checking position. At each position, a measurement is performed using the eddy current sensor unit 24 .

[0075] For example, the support member 29 is displaced by a constant interval between the first limit check position and the second limit check position.

[0076] This interval is, for example, equal to 0.1 mm.

[0077] For example, the positions are spaced apart from each other with a constant step.

[0078] As in Figure 3 and Figure 4As can be seen in detail in FIG. 2 , the longitudinal translation drive 26 comprises, for example, a cylindrical sleeve 40 surrounding the movable means 19 and a retaining means comprising the eddy current sensor unit 24 .

[0079] The translation drive device 26 cooperates with the support member 29 .

[0080] Thus, for example, the cylindrical sleeve 40 defines a circumferential neck 42 and the support 29 comprises a slide 44 cooperating with the circumferential neck 42 of the cylindrical sleeve 40 .

[0081] like Figure 2 As can be seen in the figure, the movable member 19 defines a window 45 through which the slide 44 passes to cooperate with the circumferential neck 42 .

[0082] The movable means 19 defines, at the window 45 , a longitudinal slide for the support 29 .

[0083] The cylindrical sleeve 40 is mounted so as to be longitudinally slidable on the movable member 19 .

[0084] The cylindrical sleeve 40 also allows the movable means 19 to be guided in rotation.

[0085] More specifically, when the movable means 19 rotates around the tube, the slide 44 is displaced in the circumferential neck 42 .

[0086] Furthermore, the circumferential neck 42 cooperates with the slide 44 to longitudinally drive the support 29 and thus the eddy current sensor unit 24 .

[0087] Thus, the cylindrical sleeve 40 drives the support 29 including the eddy current sensor unit 24 in longitudinal translation along the tubular element.

[0088] Preferably, the longitudinal translation drive 26 of the support 29 is a manual mechanical drive.

[0089] For example, the longitudinal translation drive device 26 further includes a gripping device 46 ( Figure 1 ).

[0090] The inspection device 10 according to the invention preferably comprises second indexing means (not shown) configured to determine the longitudinal position of the support 29 relative to the movable means 19 .

[0091] Thus, at any time, the longitudinal position of the support 29 is precisely known and indexed to each acquisition of the eddy current sensor unit 24. This ensures an accurate and high quality reconstruction of the image of the tubular element.

[0092] The eddy current sensor block 24 includes a probe 48 which includes two orthogonal electrodes relative to each other and mounted on a ferrite cube 52 ( Figure 3 ) of two orthogonal coils 50.

[0093] The coil 50 is powered, for example, in differential mode. The eddy current sensor unit 24 is therefore insensitive to the orientation of potential defects at the weld of the tubular element. During the measurement, the impedance variation of the coil 50 is analyzed along the tubular element and all around the tubular element. This measurement allows the weld of the tubular element to be mapped in two dimensions. Analysis of this mapping allows the possibility of detecting whether there is a discontinuity at the weld.

[0094] The eddy current sensor unit 24 advantageously further comprises a magnetic saturation device 54 which allows the magnetic permeability of the weld to be normalized.

[0095] For example, the magnetic saturation device 54 comprises two magnets 56 oriented in the same direction. The two magnets 56 are intended to be placed on both sides of the tubular element to be inspected, more specifically at the weld.

[0096] Advantageously, the eddy current sensor unit 24 further comprises holding means 58 for holding the probe 48 on the surface of the tubular element.

[0097] The holding device 58 allows ensuring that the probe 48 is always in contact with the surface of the tubular element and with the surface of the weld, even when the outer surface of the tubular element or of the weld is irregular.

[0098] The inspection device 10 typically comprises an acquisition unit (not shown) connected to the eddy current sensor unit 24 and to the first and second indexing devices so as to slave the measurements of the eddy current sensor unit 24 to its position relative to the weld (angular position around the tubular element and longitudinal position along the tubular element).

[0099] Typically, the measurements are transmitted to a processing unit (not shown), such as a microcomputer, for processing. The transmission is, for example, wired.

[0100] A method of inspecting a weld seam of a hollow longitudinal tubular member using the above-described inspection device 10 will now be described.

[0101] Firstly, the method comprises a step of attaching and locking the chassis 12 of the inspection device 10 on the tubular element and more specifically at the weld to be inspected, using the attachment and locking device 14 .

[0102] The method then comprises, for example, the steps of rotationally displacing the movable device 19 at least once around the tubular element relative to the chassis 12 by using the rotary drive 20 and / or translating the support 29 at least once longitudinally along the tubular element relative to the movable device 19. As a result, the eddy current sensor unit 24 is displaced into a position corresponding to the first limit check position.

[0103] A first measurement is performed using the acquisition unit with the eddy current sensor unit 24 .

[0104] The method preferably comprises, for a defined angular position, displacing the support 29 in longitudinal translation from a first extreme inspection position into a plurality of consecutive longitudinal positions up to a second inspection position. Each longitudinal position is spaced apart from the previous one by a certain interval.

[0105] For each longitudinal position, a measurement is performed with the eddy current sensor unit 24 .

[0106] When the support 29 reaches the second limit check position, the support 29 moves by longitudinal translation in a single longitudinal translation towards the first limit check position.

[0107] The movable means 19 is then rotationally moved about the tubular element relative to the chassis. The support 29 is then re-translationally displaced into a plurality of longitudinal positions between the first and second limit check positions and each position is measured with the eddy current sensor unit 24, and so on.

[0108] The displacement of the support 29 and the movable means 19 is repeated until a complete rotation of the eddy current sensor unit 24 around the tubular element. A complete rotation means that the eddy current sensor unit 24 returns to its initial angular position after performing a number of rotational displacements.

[0109] Preferably, each measurement performed with the eddy current sensor unit 24 is transmitted to an acquisition unit and then to a processing unit. The processing unit is configured to reconstruct a two-dimensional map of the tubular element at the weld seam.

[0110] As a result, users can easily and accurately identify any discontinuities in the weld.

[0111] The inspection device 10 according to the invention is accurate and reliable.

[0112] Furthermore, the dimensions of the inspection device 10 according to the invention are small enough to allow inspection of tubular elements in difficult-to-access environments, such as close to a wall. The volume of the device 10 is advantageously inscribed in a 70 mm cylinder occupying three quarters of the circumference of the tubular element. The inspection device 10 according to the invention allows surface and volume inspection of tubular elements.

Claims

1. An inspection device (10) for inspecting a weld of a hollow longitudinal tubular element, comprising: - bottom frame (12), - an attachment and locking system (14) which attaches and locks the chassis to the tubular element, the attachment and locking system preventing any movement of the inspection device relative to the tubular element, - a movable device (19) connected to the chassis (12) and capable of rotating relative to the chassis (12) around the tubular element, - a rotation drive device (20) for driving the movable device (19) to rotate relative to the base frame (12), - a support (29) comprising at least one eddy current sensor unit (24), the support (29) being connected to the movable device (19) rotatably about the tubular element relative to the base (12), the support (29) being able to translate longitudinally relative to the movable device (19), - A longitudinal translation drive device (26) for driving the support member (29) to translate longitudinally relative to the movable device (19).

2. The inspection device (10) according to claim 1, wherein: The movable means (19) comprises a first cylindrical sleeve (28) adapted to surround the tubular element.

3. The inspection device (10) according to claim 1 or 2, wherein: The rotation drive device (20) and / or the longitudinal translation drive device (26) are manual mechanical drive devices.

4. The inspection device (10) according to claim 1 or 2, wherein: The rotation drive device (20) of the movable device (19) includes a gripping device (30) which is arranged to protrude from the base frame (12) and is fixed to a driving pinion (32); and a plurality of pinions (36) which cooperate with the driving pinion (32) and the movable device (19) to drive the movable device (19) to rotate relative to the base frame (12).

5. The inspection device (10) according to claim 1 or 2, wherein: The movable means (19) is rotatably movable around the tubular element between a plurality of positions, the plurality of positions being between ten and twenty.

6. Inspection device (10) according to claim 1 or 2, further comprising at least one indexing device configured to determine the position of the movable means (19) around the tubular element.

7. The inspection device (10) according to claim 1 or 2, wherein: The longitudinal translation drive device (26) includes a second cylindrical sleeve (40) surrounding the movable device (19), the second cylindrical sleeve (40) defining a circumferential recessed neck (42), and the support member (29) includes a sliding member (44) cooperating with the circumferential recessed neck (42) of the second cylindrical sleeve (40).

8. The inspection device (10) according to claim 1 or 2, wherein: The support (29) is longitudinally translatable relative to the movable device (19) between a plurality of positions.

9. An inspection method for inspecting a weld of a hollow longitudinal tubular element by using the inspection device (10) according to claim 1 or 2, the method comprising the following steps: - attaching and locking the chassis (12) to the tubular element using an attachment and locking system (14), - using the rotary drive device (20) to displace the movable device (19) at least once in rotation about the tubular element relative to the base (12) into an angular position, and / or to displace the support (29) at least once in translation longitudinally along the tubular element relative to the movable device (19) into a longitudinal position, - Acquiring measurements using said eddy current sensor unit (24).

10. Method according to claim 9, comprising, for each angular position, displacing the support (29) in a continuous longitudinal translation along the tubular element from a first extreme check position into a plurality of longitudinal positions up to a second extreme check position.

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