FR2874019A1 - Automated repair procedure for cracks in industrial tanks uses polymerisable/reticulable adhesive contained in hollow profile and applied by robot - Google Patents

Abstract

The procedure uses a sealing material in the form of a polymerisable/reticulable adhesive (20) contained in hollow profile (10) and applied by a robot over a crack in a tank wall, normally along the line of a weld (60) between two wall sections (50, 51). The profile, e.g. of stainless steel, has a recessed central portion (13) between two side flanges (11, 12), divided into lengths by supple elastomer partitions, and the adhesive is covered by a layer of protective film prior to application. Once the crack has been detected an appropriate length of sealing profile is cut, allowing for a possible propagation of the crack, and is pressed against the defect by a robot arm after it has removed the protective film layer, and then polymerised/reticulated.

Description

AUTOMATED METHOD FOR IN SITU REPAIR OF A ZONE

  MAY INCLUDE CRACKING AT THE SURFACE OF A

PREGNANT

  The present invention generally relates to a method of repairing a zone that may comprise a crack and located on the surface of an enclosure or an industrial pool, and more particularly an automated method for an in situ repair.

  Cracks detected on the surface of walls or sails constituting an enclosure or an industrial pool generally require a rapid intervention because the mechanical and thermal stresses can facilitate the propagation of cracks. It is also preferred not to proceed with an emptying of the liquid medium and to intervene directly in situ for the repair of the crack. However, some chemically very hostile environments (hydrocarbon, water from a reprocessing pool, etc.) only allow human interventions of a very short duration to limit the risks for stakeholders. For some industries, it is even necessary to keep alert numerous teams of divers, each diver can only intervene a limited number of times a year, in a hostile environment. In addition, the qualification required for such interventions is expensive and has limited validity. A requalification of skills is usually necessary each year.

  In the case of a storage pool of radiological elements, the defects are mainly located at the weld seams linking two sails of the pool, and generally propagate longitudinally along the cord. Once the area to be treated has been located, using a robot for example, the repair is performed by a diver who intervenes directly on the defect. Possible repairs are either metal (plate welding) or organic (composite patch bonding).

  Today, there is a solution for repairing underwater by welding a stainless steel insert involving a qualified diver. The constraints of this method are on the one hand its cost (maintaining a team of qualified divers) and the other by the response time. Indeed, the time required for the intervention is in this case ten times greater than the establishment of an organic solution, resulting in very strong radioprotection constraints. Moreover, the rapid cooling of the metal in contact with the water weakens the welding of the yoke.

  Organic solutions seem more interesting. Today we know a repair using an organic yoke through the gluing of epoxy resin composite glass plates that a diver sticks on the area to be repaired.

  It remains that the existing metallic or organic solutions are only transient.

  The problems remain the same when the repair is only preventive, to mitigate a potential risk of cracking of a weld bead for example. Furthermore, the use of a yoke requires a preliminary step to adapt the yoke to the area to repair and / or protect. The adaptation is not made in situ.

  It therefore appears today needs for automated repair through a teleoperated means, allowing a fast and durable repair by means of an organic solution that can be adapted in situ to the area to be repaired.

  The object of the present invention is therefore to propose a method of repairing an area to be repaired on the surface of an enclosure or an industrial pool and which requires only one automated intervention, thus eliminating any risk factor. human.

  To this end, the subject of the present invention is an automated method for the in situ repair of an area to be repaired on the surface of an enclosure or industrial pool, and comprising the following steps: a) providing a ribbon consisting of a profile having a hollow part in the main direction of this section, this hollow part containing reservoirs of a polymerizable and / or crosslinkable adhesive substance covered by a removable film, b) cutting a portion of this strip, c) removing this removable film from the portion of the ribbon, and d) pressing the portion of the ribbon against the area to be repaired so as to apply the adhesive substance to either side of the area to be repaired.

  Thus the repair requires a single intervention of a robot, which adapts in situ the ribbon portion to the size of the area to be repaired.

  In a preferred embodiment of the method according to the invention, the tanks are separated laterally by substantially flexible partitions forming preferred zones of rupture for cutting the portion of ribbon to a cutting length depending on the size of the zone to be cut. to fix.

  Prior mapping of the areas to be repaired, using known non-destructive testing techniques for example, allows the robot to know the length of the area to be repaired. The flexible partitions ensure the separation of the tanks from each other, as well as the holding at the ends of the cut ribbon portion.

  In another embodiment of the method, the area to be repaired is located on a weld bead, the tanks being substantially of semi-cylindrical shape, and in step d), the adhesive spreads beyond the bead. .

  In a further embodiment of the method, the reservoirs are substantially semi-cylindrical in shape, and in step d) the adhesive extends beyond the reservoirs.

  The adhesive is spread out completely between the area to be repaired on the web and the surface of the ribbon profile, thus ensuring good adhesion between the ribbon portion and the area to be repaired.

  In a particular embodiment, the area to be repaired comprises one or more cracks.

  The invention also relates to a tape for the in situ repair of an area to be repaired on the surface of an enclosure or an industrial pool comprising a section having a hollow part in the main direction of this profile, this hollow part enclosing tanks of a polymerizable adhesive substance and / or crosslinkable and covered by a removable film.

  In a preferred embodiment of the ribbon, the reservoirs are separated laterally by substantially flexible partitions forming preferential zones of rupture for cutting the portion of ribbon to a cutting length depending on the size of the area to be repaired.

  In a further embodiment of the ribbon, the profile is substantially of semi-cylindrical shape.

  Other features and advantages of the invention will become apparent on reading the description which follows. This is purely illustrative and should be read with reference to the accompanying drawings in which: Figure la is a three-dimensional view of a repair tape according to the invention, Figure 1b is a view in section AA of a repair tape according to the invention, and, Figure 2 is a sectional view of the repair tape according to the invention deposited on a cracked weld seam.

  A three-dimensional view of a repair ribbon element according to the invention is visible in FIG. In the remainder of the discussion, unless otherwise stated, it will be considered that the area to be repaired includes a crack.

  This tape 10 comprises a profile having a hollow portion 13 in the main direction of the profile and two flat portions 11 and 12, substantially parallel on either side of the hollow portion. In a preferred embodiment, the hollow portion 13, as can be seen in Figure 1b, is of semi-cylindrical shape. The hollow portion 13 of the ribbon encloses a series of reservoirs 20 filled with a polymerizable and / or crosslinkable adhesive substance. These reservoirs 20 are separated laterally by substantially flexible partitions 40 which form preferential zones of rupture for cutting the ribbon to a length depending on the size of the crack to be repaired. Thus the cut ribbon portion may comprise one to several tanks, the portion being delimited on both sides by the substantially flexible partitions cut. Only three tanks are shown in the example of Figure 1a, more substantially the same size, but the ribbon according to the invention may comprise a variable number of tanks each having a suitable size, the tanks being separated from each other. others by a soup wall 40. A removable flexible film 45 (not shown in Figure la but visible in the sectional view of Figure 1b) covers the ribbon to close the tanks. The ribbon also appears as a linear element, in the main direction of the tanks and the profile.

  The defects on the surface, also called a sail, of an enclosure or an industrial pool, are mainly located at the level of the weld seams linking two sails. The cords have a main direction corresponding to the edges placed end to end of the sails welded by this cord.

  Due to the linear shape of a bead, defects generally tend to propagate in the direction of this bead.

  The area to be treated can be located either directly if it is possible to empty the enclosure or the pool, or using a robot to explore the enclosure or pool. When the area to be repaired is located, the repair is carried out by means of the repair tape according to the invention according to the method described below.

  The ribbon is set up by a teleoperated robot that moves in the enclosure or the industrial pool from the indications of location of the cracks to be repaired. The intervention of the robot is therefore preceded by a phase of localization and detection of defects or cracks (sizes, positions) and / or areas to be monitored as a preventive measure (risk of occurrence of defects or cracks). This phase uses techniques known to those skilled in the art, such as NDT (non-destructive testing), such as US (ultrasound) or CFM (eddy current).

  For the intervention, the robot carries with him one or more ribbons according to the invention as described above. Faced with the area to be repaired, it first proceeds to a cutting of a portion of the ribbon according to the invention. In a preferred embodiment, this cutting takes place at the level of the flexible partitions 40 of Figure 1a, which therefore constitute preferred areas for cutting the ribbon portion. The cut ribbon portion is a function of the size of the area to be repaired. In a second step the robot removes the removable film 45 covering the portion of the cut tape. The ribbon portion may comprise one or more tanks separated by the partitions 40 depending on the length of the crack to be repaired. In a third step, the robot applies a pressure on the portion of the cut tape against the area to be repaired so as to apply the adhesive substance contained in the tank or tanks up to either side of this zone.

  In the case where the crack is located on a weld bead, the cut ribbon portion may advantageously be longer to cover a possible propagation of the defect occurring in the direction of the bead after the repair. The ribbon appears as a particularly suitable means to take into account a possible propagation of the defect on the weld bead thanks to its linear shape which makes it possible to cover a portion of the bead.

  Figure 2 shows a sectional view of the result obtained after the pressure of a portion of the tape against the crack to be repaired.

  As can be seen in this figure, the ribbon 10 is placed on a weld bead 60 providing the connection between the webs 50 and 51 of an enclosure or an industrial pool. The ribbon 10, formed of two planar portions 11 and 12 and the semi-cylindrical portion 13, has been rotated by the robot so as to present the reservoir or tanks facing the weld beads 60 containing the crack. The pressure exerted by the robot on the profile, as well as the volume occupied by the weld bead 60, makes it possible to move the adhesive substance of each reservoir up to either side of the bead, and in particular under the plane portions 11 and 12. of the profile, so that the adhesive substance is spread on a maximum surface between the tape and the surface to be repaired. Thus, thanks to the volume of adhesive substances displaced by the volume of the weld bead 60, the adhesive can easily extend beyond this bead 60. Thin layers of adhesives 21 and 22 are then formed respectively under the flat surfaces. 11 and 12 of the ribbon portion.

  We can consider the case where the crack is located in a weld that has been abraded (and therefore has a relatively flat profile). One can also consider the case where the crack is not localized on a weld bead. The metal section must then be sufficiently flexible so that the pressure exerted by the robot during the step of application of the tape is sufficient to deform the reservoir 13. The adhesive substance is thus spread on both sides of the crack and also forms the thin layers 21 and 22 of adhesive substance under planar portions 11 and 12 of the ribbon.

  It is also possible to envisage the case where the crack or defect is not yet detected or detectable, but a repair action is necessary in the context of preventive maintenance of the cords or of a surface particularly at risk, in order to anticipate future crack formation.

  The dimensions of the weld bead are generally of the order of 5 millimeters for the width and 3 millimeters for the thickness. The dimensions of the ribbon must therefore be adapted to completely cover the weld bead to be repaired. They may be, for example, 15 millimeters in width for the plane portions on either side of the hollow portion which, for its part, may be 8 millimeters wide for a height of 4 to 8 millimeters.

  The ribbon according to the invention must allow repairs provided for edge-to-edge welds as in the example of Figure 2 and also for seam welds.

  Regarding the profile, it must be made of a material whose elastic limit allows permanent deformation when a stress is applied by means teleoperated on the latter during the third step of the method according to the invention . It can be in a stainless steel alloy, with a thickness of less than 1 millimeter, for example. The profile material must also be chemically compatible with its environment (chemical composition, or even chemical radio of the environment). The shape of the hollow part of the profile must allow the flow of the polymerizable and / or crosslinkable adhesive substance beyond this hollow portion during the application of pressure, or even crushing, during the third step of the process according to the invention.

  The polymerizable and / or crosslinkable adhesive substance contained in the hollow portion of the tape is a curable substance and comprises a silicone having a number of properties. It must in particular have a suitable viscosity to allow its flow during the introduction of the tape during the third step of the method according to the invention. It must be sufficiently viscous not to flow out of the cavity during the introduction of the tape. It must also be able to crosslink in the water or in any other liquid medium contained in the enclosure or the industrial pool. It must be able to develop a strong physical affinity with the support to be treated (strong adhesion on the highly humid substrate). However, it must remain ductile enough to maintain a good interfacial resistance during successive dilutions of the support. It must also have good resistance to shear fatigue. It must finally be compatible with the chemical constraints of the liquid medium contained in the enclosure or the industrial pool.

  The removable film 45 which covers the ribbon according to the invention must be compatible with the chemical environment of the liquid contained in the enclosure or the industrial pool so as not to degrade during the intervention. It must also have a very weak interaction with the silicone so as to be easily releasable without extracting the silicone from the ribbon reservoirs when it is removed. This film can for example be Teflon.

  The substantially flexible partitions may consist of elastomers compatible with the chemical environment of the liquid medium of the enclosure or the industrial pool. They must also support the pressure, or crushing, exerted by the robot during the third step of the method according to the invention. They must also deform to come to marry the shape of the weld bead (if the repair takes place on a weld), during the third step of the method according to the invention. Finally, they must be easily cut to form preferred areas of rupture without generating particles likely to become migrating bodies in the liquid medium. They must also guarantee the sealing function of the ribbon since they constitute the walls of the ends of the cut ribbon portion.

Claims (1)

9 CLAIMS   1. An automated method for the in situ repair of an area to be repaired on the surface of an enclosure or an industrial pool, and comprising the following steps: a) providing a ribbon consisting of a profile (11, 12, 13 ) having a hollow portion (13) in the main direction of said profile, said hollow portion enclosing reservoirs (20) of a polymerizable and / or crosslinkable adhesive substance covered by a removable film (45), b) cutting a portion of said ribbon c) removing the removable film from said portion of the ribbon; and, d) applying pressure to said ribbon portion against said zone so as to apply said adhesive substance to either side of said area to be repaired.   2. Automated method according to claim 1, characterized in that the tanks are separated laterally by substantially flexible partitions (40) forming preferred zones of rupture for cutting the portion of ribbon to a cutting length depending on the size of the the area to be repaired.   3. Automated method according to one of the preceding claims, wherein the area to be repaired is located on a weld bead (60), and characterized in that the tanks are substantially of semi-cylindrical shape, and in that step d), the adhesive spreads beyond the bead.   4. Automated method according to one of claims 1 and 2, characterized in that the tanks are substantially of semi-cylindrical shape, and in that, in step d), the adhesive extends beyond tanks.   5. Automated method according to one of the preceding claims wherein the polymerizable and / or crosslinkable adhesive substance is a silicone-based substance.   6. Automated method according to one of the preceding claims wherein the substantially flexible partitions consist of elastomers.   7. Automated method according to one of the preceding claims wherein the area to be repaired comprises a crack.   8. Automated method according to claims 3 and 7, wherein the size of the cut ribbon portion takes into account a possible propagation of the crack.   9. Tape (11) for the in-situ repair of an area to be repaired on the surface of an enclosure or industrial pool characterized in that it comprises a profile (11, 12, 13) having a hollow portion (13) in the main direction of said profile, said hollow portion enclosing reservoirs (20) of a polymerizable and / or crosslinkable adhesive substance covered by a removable film (45).   The tape of claim 9, wherein the reservoirs are laterally separated by substantially flexible partitions (40) forming preferred break zones for cutting the tape to a length dependent on the size of the area to be repaired.   The tape of claims 9 or 10, wherein the adhesive substance is a silicone-based substance.   12. Tape according to one of claims 9 to 11, wherein the profile is substantially of semi-cylindrical shape.   13. Tape according to one of claims 9 to 12, wherein the substantially flexible partitions consist of elastomers.   14. Tape according to one of claims 9 to 13, wherein the area to be repaired comprises a crack.