Method for processing a sealing film suitable for a tank and corresponding device - Patent application

Abstract

The invention relates to a method for treating a sealing film (2) for a tank intended to contain a gas in liquid state, the method using a treatment tool (72) attached to a movable device (70), the treatment method comprising the steps of: - generating a profile of a portion of the sealing film (2) for a predetermined path of the movable device (70) relative to the sealing film (2), - dividing the predetermined path into treatment zones, between which at least one change in the configuration of the movable device (70) and / or the treatment tool (72) is required, - treating the sealing film (2), and - at least one substep of changing the configuration of the movable device (70) and / or the treatment tool (72) between two of the treatment zones during the treatment step.

Description

[Technical Field]

[0001] The present invention relates to the field of tanks for gases in liquid state, such as liquefied natural gas (LNG), in particular for marine or river transport or land-based storage, and more particularly to a method for treating sealing membranes suitable for such tanks. [Background technology]

[0002] Each of these transport tanks can be several thousand m 3 or tens of thousands of m 3 Liquefied gases can even hold up to 1000 cubic meters of liquid gas. Ships transporting liquefied gas have holds specially equipped to accommodate these tanks, which are often divided into multiple tanks. Such tanks may also be built off-ship for on-shore storage of the liquid gas. The gas is maintained in a liquid state at atmospheric pressure, e.g., -163°C (-163°C) for LNG. Therefore, the tanks must be waterproof and insulated. As a result, the interior surfaces of such tanks are usually covered by a sealing membrane made from an assembly of metal sealing plates (typically stainless steel) welded together, each sealing plate being part of the tank's sealing membrane.

[0003] To weld these metal plates together, a welding machine is used, and the operator must use a guide rail to follow the edges of these sealing plates, which are placed partially adjacent to each other in pairs (clinch joints). The operator runs a program on the machine, and the machine, equipped with a welding torch, welds them as it passes over the edges of the sealing plates, constantly adjusting the distance between the torch and the parts being welded using a positioning sensor attached to the machine.

[0004] Following this operation, the weld bead is stripped because the welding operation can create metal oxides on the edges of the sealing plate, which can eventually compromise the integrity of the film (corrosion). The stripping operation uses a machine equipped with a position sensor and a laser stripping head, which uses the same guide rail to gradually strip the weld bead created by the welder. The position sensor allows the laser stripping head to be positioned as the machine moves along the rail.

[0005] These welding and stripping operations are extremely time consuming. Because the contours of the sealing film must be taken into account, the machine moves slowly along the edge of the sealing plate to be welded or stripped. Proper positioning of the welding torch or laser stripping head takes time, slowing down the welding or stripping operation. Summary of the Invention [Problem to be solved by the invention]

[0006] Therefore, there is a need to improve the performance time of welding and / or stripping operations on sealing membranes of tanks for transporting gases in liquid state. [Means for solving the problem]

[0007] The present invention at least partially remedies the drawbacks of the prior art by providing a method for treating a sealing film suitable for a tank intended to contain a gas in liquid state, which makes it possible to facilitate the treatment carried out on the sealing film of a tank for a gas in liquid state. To this end, the present invention provides a method for treating a sealing film suitable for a tank intended to contain a gas in liquid state using a treatment device for treating sealing films, the treatment device comprising a movable device and at least one treatment tool attached to the movable device, the treatment method comprising the step of treating the sealing film by the treatment tool along a predetermined path of the movable device, the treatment method comprising: a preliminary step of generating a profile of at least a portion of the sealing film relative to a predetermined path using a movable support provided with a position sensor, and a passage of the position sensor over the sealing film, during which: - determining a distance between a reference point of the position sensor and at least one point of the sealing membrane portion; - recording the determined distance; - moving the movable support; Repeated passage and Including, The method, wherein the generation of the profile of the sealing film portion is correlated to the distance recorded during the recording substep, The processing method is - dividing the predetermined path into treatment areas of the sealing film according to the profile generated during the generating step, between which at least one change in the configuration of the movable devices and / or processing tools is required; - at least one substep of changing the configuration of movable devices and / or processing tools between two of said processing areas during the processing step; The present invention proposes a method for processing, characterized in that it further comprises:

[0008] In particular, if the position sensor is an optical sensor, the sub-step of determining the distance comprises: - transmitting an initial optical signal to a point on the surface of the sealing film; receiving a return optical signal corresponding to the initial optical signal; - determining a distance between a reference point of the position sensor and a point on the surface of the sealing film in response to the initial light signal and the return light signal; Includes.

[0009] The generated profile is, for example, a two-dimensional profile of the sealing film portion in a plane perpendicular to the main plane of the extension of the sealing film portion.

[0010] The predetermined path may be derived from a step of analyzing the profile generated in a step prior to generating the profile.

[0011] According to the present invention, a profile of the sealing film portion is generated and made available to subsequent processing steps of the sealing film portion, and prior knowledge of the film profile accelerates the performance of the processing step. According to the present invention, the subsequent processing step does not use a position sensor to determine the distance between the processing tool and the sealing film and the positioning of the processing tool relative to the film, but the processing step may use another sensor to ascertain the position of the processing tool, for example along a predetermined path.

[0012] In one embodiment of the present invention, the sealing membrane comprises a first sealing plate and a second sealing plate arranged in contact with each other, the sealing membrane portion being the edge of the first sealing plate, and a portion of the edge of the second sealing plate being arranged below the edge of the first sealing plate, and the passage of the position sensor is also suitable for determining the distance between a point on the edge of the second sealing plate and a reference point of the position sensor, and the generating step generates a profile of the edge of the first sealing plate and a profile of the edge of the second sealing plate. The edge of the second sealing plate refers to the peripheral region of the second sealing plate. More specifically, the edge of one sealing plate is arranged above a portion of the other sealing plate (hereinafter, this portion may be referred to as the edge of the plate, although not necessarily the periphery of the plate).

[0013] In this embodiment of the invention, the movable supports are mounted on rails fixed to the sealing membrane, for example along the edges of the first and second sealing plates. If the sealing membrane comprises corrugations that assist the deformation of the tank and these corrugations form a grid on the sealing membrane, the rails are fixed, for example, to at least two nodes of the grid, and the distance between the edges of the sealing plates of the sealing membrane and the rails is substantially constant, i.e. constant within + / - 3 mm.

[0014] According to an advantageous feature of the invention, the position sensor is a scanning laser sensor, the distance determining substep corresponds to a substep of determining a plurality of distances for one and the same position of the movable support, and the generating step generates a three-dimensional profile of the sealing membrane portion, so that if the sealing membrane portion comprises two sealing plate edges lying in contact with each other, this three-dimensional profile includes the profile of each sealing plate edge of this sealing membrane portion.

[0015] The movable device is also preferably a movable support and thus comprises both a position sensor and a processing tool, although the position sensor is not used during the processing steps. The processing device may comprise rails on which the movable device runs, and / or a remote server.

[0016] According to an advantageous feature of the processing method according to the invention, the processing step comprises at least one sub-step of changing the configuration of the movable equipment and / or processing tools, the processing step being preceded by a step of dividing the predetermined path into processing regions of the sealing film according to the profile generated during the generating step, between which said at least one sub-step of changing the configuration of the movable equipment and / or processing tools is necessary. Thus, prior knowledge of the profile of the sealing film portions allows a sequential processing of the process, each processing sequence corresponding to a processing region in which a change in the configuration of the movable equipment and / or processing tools is not necessary, such a sub-step of changing the configuration being carried out only between each processing sequence.

[0017] The treatment areas are preferably ordered by the treatment device in a treatment sequence that allows minimizing the treatment time of the sealing film by the treatment device, which may correspond to a discontinuous treatment of the sealing film during a first pass of the movable device over the sealing film, after which multiple passes are required to treat the entire sealing film over a given path.

[0018] In one embodiment of the treatment method according to the invention, the treatment corresponds to an operation of peeling off the weld bead at the level of two sealing plate edges of the sealing film, the sealing film portion being the edge of the first sealing plate and the edge of the second sealing plate being arranged in contact with the edge of the first sealing plate.

[0019] In one embodiment of the processing method according to the invention, the reconfiguration substep generates a displacement of the mobile equipment and / or processing tools, and processing is interrupted during said reconfiguration substep, in other words, the reconfiguration substep corresponds to an "empty" movement of the mobile equipment and / or processing tools, i.e. a movement without any processing.

[0020] In an embodiment of the treatment method according to the present invention, the sealing film has corrugations, which form a grid on the sealing film, the treatment tool is a laser stripping head positioned on a predetermined path for stripping the weld bead, and the reconfiguration substep is triggered to position the impact point of the laser beam projected by the laser stripping head on the region located at the foot of the corrugation of the sealing film. Thus, by the reconfiguration substep, the treatment tool can be positioned to completely treat the treatment region, and in this case, the laser stripping head is positioned to scan the entire region located at the foot of the corrugation of the sealing film with the impact point of the laser beam.

[0021] The treatment areas are configured to allow ablation using only laser scanning for each of the treatment areas, for example, without any additional movement of the moving device or laser ablation head.

[0022] In another embodiment of the processing method according to the invention, the processing step comprises at least one sub-step of changing the configuration of the movable equipment and / or processing tools, and the processing step comprises a sub-step of reading the profile generated during the generating step and determining a trigger for said at least one sub-step of changing the configuration of the movable equipment and / or processing tools. In this another embodiment of the invention, the profile reading sub-step is performed entirely before the processing step or is performed during the performance of the processing step. The reading of the profile determines the moment when the configuration of the movable equipment and / or processing tools needs to be changed when the processing step is performed.

[0023] In this alternative embodiment of the treatment method according to the invention, the treatment corresponds, for example, to a welding operation at the level of two sealing plate edges of a sealing membrane, the sealing membrane portion being the edge of the first sealing plate and the edge of the second sealing plate being arranged in contact with the edge of the first sealing plate.

[0024] For example, in this other embodiment of the treatment method according to the invention, the sealing film comprises corrugations, which form a grid on the sealing film, the treatment tool is a welding tool, and the modifying substep corresponds to modifying the speed of the movable device when it reaches the corrugations of the sealing film. Thus, in this example, the reading substep makes it possible to detect the foot of the corrugations of the sealing film portion to be welded, which makes it possible to adapt the speed of the movable device.

[0025] The treatment step is optionally followed by a further step of generating a profile of the portion of the sealing film that has just been treated, which makes it possible to implement a method for controlling the sealing film, the method for controlling comprising: - generating a profile of at least a part of a sealing film using the method for generating a profile according to the invention; - comparing the distances obtained using the previously generated profile with the corresponding distances of a pre-registered template of the sealing membrane portion; Includes.

[0026] The difference in absolute values ​​of these distances is compared, for example, with a predetermined threshold, and if this difference is greater than this predetermined threshold, an anomaly is detected.

[0027] The present invention relates to a device for generating a profile of at least a part of a sealing membrane suitable for example for a tank adapted to contain a gas in liquid state, the device comprising a movable support provided with a position sensor, the device also comprising: means for determining the distance between a reference point on the position sensor and at least one point on the sealing membrane portion; - means for recording the distance determined by the determining means; means for moving the movable support along a predetermined path above the sealing membrane; means for generating a profile of the sealing film portion according to the distance recorded along the predetermined path by the recording means; Use the device, including

[0028] The generator may comprise rails on which the movable support runs, and / or a remote server.

[0029] Further characteristics and advantages of the invention will become apparent from the following description on the one hand and from a number of example embodiments, given by way of illustration and without limitation with reference to the attached schematic drawings, in which: FIG. [Brief explanation of the drawings]

[0030] [Figure 1] 1 illustrates an apparatus for generating a profile of at least a portion of a sealing film during a step in which a position sensor passes over the sealing film in one embodiment of the present invention. [Figure 2] 1A-1C illustrate steps for creating a profile of at least a portion of a sealing film according to the present invention, in one embodiment of the present invention. [Figure 3] 1 illustrates an apparatus for welding sealing membranes, which performs the step of welding a sealing plate to an adjacent sealing plate in one embodiment of the present invention. [Figure 4] 1A-1D illustrate steps of a method for welding a sealing membrane according to the present invention, in one embodiment of the present invention. [Figure 5] FIG. 2 is a diagram illustrating an apparatus for peeling off a sealing film, which performs a step of peeling off the sealing film in one embodiment of the present invention. [Figure 6] 6 is a diagram showing a collision area of ​​a laser beam of the peeling device shown in FIG. 5. FIG. [Figure 7] FIG. 1 shows a stripping head for this laser beam with a reflector module. [Figure 8] 1A-1C illustrate steps of a method for stripping a sealing film according to the present invention, in one embodiment of the present invention. [Figure 9] 9 is a diagram illustrating the peeling of the corrugated portion of the sealing film during the peeling step of the peeling method of FIG. 8. FIG. [Figure 10] 1A-1D illustrate method steps for controlling a sealing membrane in one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0031] According to the embodiment of the invention shown in Figure 1, a profile of a portion of a sealing membrane 2 suitable for a tank configured to contain a gas in liquid state is generated using a profile generation device 1. In this embodiment of the invention, the sealing membrane 2 is made from metal plates with a thickness of 1.2 mm that are welded to each other or are to be welded to each other.

[0032] The tanks are typically bounded by the inner hull of the carrier and can extend for several thousand m 3 or tens of thousands of m 34000 psi. The sealing membrane 2 covers the entire inner surface of the tank of such a carrier. In order to compensate for deformations of the tank due to temperature changes or navigation conditions, the sealing membrane 2 is provided with ribs or corrugations 24 that intersect the surface of the sealing membrane 2. When viewed in profile in a plane parallel to the longitudinal direction L and in a plane parallel to the transverse direction T that is perpendicular to the longitudinal direction L, the sealing membrane therefore comprises flat areas 22 and corrugations 24.

[0033] The profile generating device 1 comprises a movable support 11 equipped with a position sensor 12 that measures the distance separating a reference point on the device from an impact point on the membrane. The position sensor 12 is a class 2 laser distance sensor with a measurement frequency of 300-600 Hz (Hertz). Alternatively, the position sensor 12 may be an LVDT (Linear Variable Differential Transformer) type sensor.

[0034] In this embodiment of the invention, the movable support 11 is mounted opposite the edge of the sealing plate 2-1 of the sealing membrane 2 on a rail 3 positioned approximately 10 cm above the surface of the sealing membrane 2. In this embodiment of the invention, a profile of the edge of the sealing plate 2-1 of the sealing membrane 2 is generated.

[0035] The rails 3 run along the edges of the sealing plate 2-1 in the longitudinal direction L. The distance between the edges of the sealing plate 2-1 and the rails 3 is constant within a few centimeters. The rails may be several tens of meters long, for example 30 meters long, and may be manufactured in multiple pieces. The rails 3 are held in place by clamps 4, for example, attached to the nodes of the grid formed by the corrugations of the sealing film 2.

[0036] The step 200 of generating the edge profile of the sealing plate 2-1 is performed by the generating device 1 by means of software and / or hardware and is illustrated in FIG.

[0037] The step 200 of generating the profile is preceded by a step 100 of passing the position sensor 12 over the edge of the sealing plate 2-1.

[0038] The passage 100 of the position sensor comprises a first sub-step 102 of determining the distance d between a reference point of the position sensor 12 and a point on the surface of the sealing plate 2-1. The point on the surface of the sealing plate 2-1 is perpendicular to the position sensor 12. In this embodiment of the invention, the position sensor 12 measures in a vertical direction V relative to the position sensor 12, which is orthogonal to the longitudinal direction L and the transverse direction T. In this determination sub-step 102, the generator 1 reads the measurements returned by the position sensor 12. The generator 1 comprises a software module interconnected to the input and the output of the position sensor 12. Thus, in this embodiment of the invention, sub-step 102 itself comprises sub-steps performed by the position sensor 12, which sub-steps are: a substep 1022 of transmitting an initial light signal, for example a laser pulse, to a point on the surface of the edge of the sealing plate 2-1; a substep 1024 of receiving a return optical signal corresponding to the initial optical signal, for example a reflection of the laser pulse initially transmitted to the surface of the sealing plate 2-1; a substep 1026 of measuring the distance d between a reference point of the position sensor 12 and a point on the surface of the edge of the sealing plate 2-1 as a function of the initial and return optical signals, this measurement typically using the time between sending a laser pulse and receiving a reflected laser pulse; is.

[0039] Alternatively, another type of sensor may be used, such as, for example, an infrared optical sensor or a capacitance sensor.

[0040] Subsequent to step 100 of passing the position sensor 12 , substep 104 is to record the distance d determined in substep 102 in the memory of the generator 1 .

[0041] Finally, the last sub-step 106 of step 100 of passing the position sensor 12 is to displace the movable support 11. The generator 1 comprises a software module interconnected to the actuator of the movable support 11. The speed of movement of the movable support 11 in combination with the pulse frequency of the laser beam results in movement steps, for example tenths of mm, and in this embodiment of the invention the speed of movement of the movable support 11 is 100-200 mm / s (millimeters per second).

[0042] Sub-steps 102 to 106 of step 100 of passing the position sensor 12 are repeated until the mobile support 11 reaches the end of the rail 3 or there is any stop instruction or command.

[0043] When the end of the rail is reached, this is detected by the generating device 1, for example by detecting an abutment on the rail 3 or by detecting the reaching of a predetermined distance of travel on the rail 3 programmed in the generating device 1, and the generating device 1 carries out a step 200 of generating a profile of the edge of the sealing plate 2-1 according to the distance recorded during the recording substep 104. The generating step 200 is implemented in a software module of the generating device 1, which may comprise a remote server.

[0044] During this generating step 200, in this embodiment of the invention, the generator 1 generates a profile of the edge of the sealing plate 2-1 in the form of a point in a reference frame located in a plane orthogonal to the main plane of extension of the sealing membrane 2, i.e. parallel to the vertical direction V and the longitudinal direction L. The profile generated is therefore a profile having at least two dimensions, one dimension corresponding to the position reached by the movable support 11 on the rail 3 since the start of step 100, and the other dimension corresponding to the distance d determined by the generator 1 during sub-step 102 when the movable support 11 reached this position on the rail 3.

[0045] Depending on the use of the generated profile, the generating device 1 filters the distance d recorded during sub-step 104, and then the generated profile includes only certain points corresponding to the distance d recorded, for example, at the boundary of the flat region 22 and the top of the corrugated portion 24 of the sealing film 2.

[0046] In an alternative embodiment of the invention, the position sensor 12 is a scanning laser sensor, which measures, for the same position on the rail 3 of the position sensor 12, the distance between a reference point of the position sensor 12 and various points on the surface of the sealing film 2 located on a line parallel to the transverse direction T, and these distances are measured in a vertical plane parallel to the transverse direction T and the vertical direction V, which passes through the position sensor 12. In this alternative embodiment, the generator 1 determines a distance vector for the same position of the movable support 11 in each sub-step 102, and this vector is recorded in sub-step 104. Therefore, in this alternative embodiment, the profile generated in step 200 is a three-dimensional profile of the edge of the sealing plate 2-1.

[0047] If the edge of the sealing plate 2-1 is arranged on the edge of another sealing plate 2-2 (in Figure 6 it is welded to the sealing plate 2-1), for example if it is welded to this other edge, the three-dimensional profile generated in this alternative embodiment is, for example, the profile of the edge of the first sealing plate 2-1 and the profile of the edge of the second sealing plate 2-2.

[0048] In another embodiment of the invention, the movable support 11 is not arranged on rails 3 but runs along at least a portion of the sealing film 2, moving directly on the surface of the sealing film 2 along a predetermined or adaptive path depending on the obstacles that the movable support 11 encounters on its path.

[0049] An example of a method for processing a sealing film 2 using the profile generating step 200 according to the invention will now be described. In this use case shown in Figure 3, the processing method is a method for welding the edge of a sealing plate 2-1 to the edge of a sealing plate 2-2, implemented in hardware and / or software by a welding device 7.

[0050] The welding device 7 comprises a rail 3 that follows the edge of the sealing plate 2-1 and a movable device 70 on which a welding torch 72 is mounted. The welding device 7 may also comprise a remote server. Alternatively, the welding device 7 comprises a movable device consisting of a movable support 11 of the generating device 1, which in this case comprises a welding torch in addition to a position sensor 12, and possibly a laser stripping head 52 used for the subsequent stripping operation (illustrated in FIG. 5).

[0051] The welding method performed by the welding apparatus 7 shown in FIG. 4 includes an initial step 100 of passing the position sensor 12 and a step 200 of generating a profile of the edge of the sealing plate 2-1, the steps of generating the profile being performed as described above in relation to FIGS. 1 and 2.

[0052] The next step 600 in the welding method is to clinch weld the edges of sealing plates 2-1 and 2-2 together using welding torch 72. During this welding step, sealing plates 2-1 and 2-2 are welded together by melting material from the edge of sealing plate 2-1 to the edge of sealing plate 2-2, which melting occurs as movable device 70 advances along rail 3.

[0053] The first substep 602 is a step of reading the profile of the edge of the sealing plate 2-1 generated during the profile generation step 200. The generated profile is a two-dimensional profile in a plane parallel to the longitudinal direction L and the vertical direction V, and includes the division of the predetermined path into areas to be welded, which are flat areas 22 or corrugated areas 24, thereby making it possible to identify the corrugated areas 24 and the flat areas 22. The profile includes, for example, values ​​of parameters that indicate the nature of the areas vertically above the welding torch 72 for each position of the movable device 70 on the rail 3, for example, a value of 0 being assigned to the flat areas 22 and a value of 1 being assigned to the corrugations 24.

[0054] The reading substep 602 is carried out continuously, either simultaneously with the movement of the movable device 70 along the rail 3, or before the movement of the movable device 70 along the rail 3. Indeed, the reading substep 602 makes it possible to detect positions of the movable device 70 at which the speed of the movable device 70 needs to be modified during welding of the sealing plates 2-1 and 2-2 of the sealing film 2. These positions may therefore be predetermined, distinguishing between the flat areas 22 and the corrugated portions 24.

[0055] In this embodiment of the welding method according to the invention, a reading substep 602 is performed as the movable device 70 advances along the rail 3. The speed of the movable device 70 remains constant as long as the nature of the vertical area of ​​the welding torch 72 detected during this reading substep 602 does not change. If the nature of the vertical area of ​​the welding torch 72 detected during this reading substep 602 changes, the reading substep 602 triggers a substep 604 for changing the speed of the movable device 70. In particular, during this substep 604: - when the passage from the flat area 22 to the foot of the corrugation 24 is detected in the reading substep 602, the speed of the movable device 70 is reduced and the orientation of the welding torch is changed by parameter adaptation, - When the passage from the foot of the corrugation 24 to the flat area 22 is detected in the reading substep 602, the speed of the movable device 70 is increased again and the orientation of the welding torch is changed by parameter adaptation.

[0056] Based on the three-dimensional profile generated as described above, during the reading substep 602, any deviations in the position of the membrane can be detected and transverse corrections can be made to correctly position the welding torch.

[0057] A further example of a method for treating a sealing film 2 using the profile generating step 200 will now be described. In this alternative use case, shown in Figure 5, the treatment method is a method for stripping a weld bead 26 between an edge of a first sealing plate 2-1 and an edge of a second sealing plate 2-2, implemented by a stripping device 5 by means of hardware and / or software.

[0058] The stripping device 5 comprises a rail 3 that follows the edge of the sealing plate 2-1 and a movable device consisting of a movable support 11 for the generator 1 that includes both a position sensor 12 and a laser stripping head 52. The stripping device 5 may also include a remote server.

[0059] Advantageously, the stripping device 5 may also be equipped with a suction nozzle (not shown) making it possible to suck up oxide dust or fumes produced during stripping of the sealing film 2. It will be understood that the stripping device 5 performs pickling via a laser beam projected onto the area to be pickled.

[0060] The laser stripping head 52 may be tilted relative to the movable support 11, so that the laser stripping head 52 projects the laser beam 6 at an angle of incidence 27 of the order of several degrees relative to a normal 25 to the surface of the sealing film 2. This prevents reflection of the laser beam 6 projected by the laser stripping head 52, preventing damage to the laser stripping head 52 from the return of the incident beam. In practice, the laser stripping head 52 projects a Class 4 laser beam 6 (in accordance with standard 1EC60825-1), preferably with a power between 20 W and 200 W, pulsed at a frequency between 100 kHz and 200 kHz, and generating a beam with a wavelength of 1064 nm. These characteristics of the laser beam 6 make it possible to strip the impurity or oxide layer 28 formed on the weld bead 26.

[0061] The movable support 11 is provided with an electric motor 53 that can rotate a rotation shaft 51 fixed to the laser stripping head 52. In this manner, the laser stripping head 52 may be capable of rotational movement relative to the movable support 11, thereby changing the angle of incidence 27 of the laser beam 6 with respect to the normal 25 to the surface of the sealing film 2. Therefore, the stripping device 5 is provided with a means for changing the inclination of the laser stripping head 52 with respect to the normal 25 to the surface of the sealing film 2.

[0062] The stripping device 5 also comprises means, not shown, for changing the height h of the rotation axis 51 on the movable support 11 and thus the height of the laser stripping head 52 in the vertical direction V.

[0063] These means for changing the inclination and height of the head 52 are means for changing the configuration of the laser stripping head 52 mounted on the movable support 11. Alternatively, the stripping device 5 comprises means for changing the height of the movable support 11 relative to the rail 3.

[0064] The peeling device 5 also comprises means for moving the movable support 11 on the rails 3, which means are identical to the means used for moving the device 1 for generating the profile, i.e. software interconnected to at least one actuator of the movable support 11.

[0065] The laser stripping head 52 includes at least one focusing lens 54 with a focal length between 80 mm and 360 mm, which enables the laser beam 6 to be focused onto an impact area 61 on the surface of the sealing film 2. The laser beam 6 scans across this impact area 61, with each pulse forming an impact point 63, as shown in Figure 6, which overlaps with each other to ensure complete stripping of the weld bead 26. The impact area 61 is approximately 2 cm wide (in the transverse direction T), which means that a weld bead 26 with a width of approximately 1 cm can be completely stripped.

[0066] This scanning is made possible by the structure of the laser ablation head 52 shown in FIG. 7. The ablation device 5 comprises a laser beam generator 56 that projects a laser beam 6 onto a reflecting module 57 at the free end of the laser ablation head 52. The laser ablation head 52 is shown in a highly simplified form in FIG. 7 for ease of explanation. The laser beam generator 56 is actually external to the laser ablation head 52, and a fiber 9 guides the generated beam to the laser ablation head 52. The reflecting module 57 is, for example, an assembly of mirrors that deflects the trajectory of the laser beam 6 leaving the beam generator in a direction D1 contained in a plane parallel to the longitudinal direction L and the vertical direction V, or in a direction D2 contained in a plane parallel to the transverse direction T and the vertical direction V. Alternatively, the reflecting module is located on a movable support 11 outside the laser ablation head 52. The ablation device 5 therefore comprises a means for changing the orientation of the laser beam 6 independently of the orientation of the laser ablation head 52.

[0067] The method for stripping the weld bead 26 performed by the stripping device 5 includes an initial step 100 of passing the position sensor 12, as shown in FIG. 8, and a step 200 of generating a profile of the edge of the sealing plate 2-1, and the method for generating the profile described above in connection with FIGS. 1 and 2 is performed.

[0068] The next step 400 is to divide the predetermined path of the stripping device 5 along the rail 3 into treatment areas of the sealing film 2, in this case the to-be-stripped areas, which correspond to the path along the portion of the sealing film 2 to be treated according to the profile generated in step 200. For this area, the laser stripping head 52 or the movable support 11 must be reconfigured before stripping the to-be-stripped area in question.

[0069] To increase the peeling speed (mm / s) of the edges of the sealing plates 2-1 and 2-2, it is preferable to limit the movement of the movable support 11 and the laser peeling head 52 as much as possible. To achieve this, the peeling method sequentially peels the peeled regions cut during step 400, and these peeled regions are configured so that peeling can be performed in each of these regions using only the laser scanning enabled by the reflection module 57, without any additional movement of the movable support 11 or the laser peeling head 52. To achieve this, the size of the peeled regions is predetermined to keep the incidence angle 27 small enough to effectively peel the peeled regions. In particular, this incidence angle ensures that the focal length of the focusing lens 54 remains within an acceptable tolerance range. For example, for a focusing lens 54 with a focal length of 330 mm (millimeters), this tolerance range is 3 mm.

[0070] Thus, in this step 400, the flat regions 22 are each divided into two halves, and the corrugations 24 are each divided into six regions to be stripped, as shown in FIG. 9 . More precisely, as the movable support 11 moves in the longitudinal direction L in the direction 55, the movable support 11 first strips the slopes 241 of the corrugations 24. To effectively strip these slopes 241, the laser beam emerging from the reflecting module 57 has an angle of incidence 27 of approximately zero on the surface of the corrugations 24. To do this, the laser stripping head 52 uses a rotation axis 51, which allows the laser beam 6 to have an angle of 70° or 50° counterclockwise with respect to the vertical at the output of the laser stripping head 52.

[0071] Therefore, the first peeled area 243 of the foot of the slope 241 is defined to be irradiated by the laser beam 6 at an angle of 70° with respect to the vertical direction V, which makes it possible to adjust the radius of curvature of the foot of the corrugated portion 24 to within a few degrees.

[0072] The second peeled area 245 in the center of the slope 241 is also defined to be irradiated by the laser beam 6 at an angle of 50° relative to the vertical direction V, which allows the normal to the surface of the corrugated portion in the central region of the slope 241 to be aligned within a few degrees.

[0073] Finally, the third stripped area 247 at the top of the slope 241 is defined so that it may be struck by the laser beam 6 at an angle of 50° relative to the vertical direction V, thereby allowing the radius of curvature of the top of the corrugated portion 24 to be adjusted to within a few degrees.

[0074] Similarly, when the movable support 11 moves in the other direction 59 of the longitudinal direction L, the movable support 11 peels the other slope 242 of the corrugation portion 24 in a manner similar to peeling the slope 241 of the corrugation portion 24. Specifically, the movable support 11 starts peeling a fourth region 244 at the foot of the slope 242, with the laser beam 6 having an angle of 70° clockwise with respect to the vertical direction V, then starts peeling a fifth region 246 at the center of the slope 242, with the laser beam 6 having an angle of 50° clockwise with respect to the vertical direction V, and finally starts peeling a sixth region 248 at the top of the slope 242, with the laser beam 6 having an angle of 50° clockwise with respect to the vertical direction V.

[0075] The regions to be stripped 243, 245, 247, 244, 246, 248 overlap one another at least at one transverse edge, so that stripping is performed seamlessly across the entire weld bead 26 along a predetermined path.

[0076] At the end of step 400, the peeling device 5 stores data in a ROM (Read Only Memory) or RAM (Random Access Memory) memory, in which the predetermined path is divided into regions to be peeled, each of which is assigned to a single configuration of the movable support 11 and / or laser peeling head 52. While peeling the regions to be peeled in step 400, the movable support 11 and the laser peeling head 52 remain stationary. The regions to be peeled are also listed by the peeling device 5 in a processing order that makes it possible to minimize the time required for the peeling device 5 to peel the sealing film 2. As will be explained later, this order does not correspond to continuous peeling along the predetermined path.

[0077] It should be noted that, alternatively, the dividing step 400 is performed, at least in part, in parallel with the profile generating step 200 .

[0078] The next step is a processing step of the sealing film 2 by a processing device, in this case a stripping step 500 performed by a stripping device 5 along a predetermined path. This processing step includes at least one substep of changing the configuration of the movable device and / or processing tools of the processing device, in this case substep 502 of changing the configuration of the movable support 11 and / or the laser stripping head 52. In particular, substep 502 corresponds to changing the height of the laser stripping head 52 and / or the position of the movable support 11 on the rail and / or the angle of the laser stripping head 52 relative to an axis perpendicular to the main plane of extension of the sealing film 2.

[0079] Unlike the prior art, the peeling step 500 does not use a position sensor for the sealing film 2 .

[0080] More precisely, at the start of the peeling step 500, the peeling device 5 positions the movable support 11 longitudinally on the rail 3 and orients the laser peeling head 52 in such a way that it can peel the first area to be peeled in the list of areas to be peeled obtained from the dividing step 400 without any additional movements of the movable support 11 and the laser peeling head 52. This change to the configuration of the movable support 11 and / or the laser peeling head 52 corresponds to the first configuration change sub-step 502 for the current area to be peeled, i.e. for this first area to be peeled, at the start of step 500.

[0081] The second sub-step 504 of the ablation step 500 is to ablate the current ablation area using a laser beam 6 that scans the current ablation area. For reference, the ablation speed in this example is 7 cm 2 / s (square centimeters per second).

[0082] Finally, the third sub-step 506 of the peeling step 500 is to change the current peeled region if the list of regions to be peeled has not been completely exhausted, otherwise it is the end of the peeling step 500. If the list of regions to be peeled has not been completely browsed, the current region to be peeled is replaced with the region to be peeled immediately after the current region in the list of regions to be peeled, and the next sub-step of the peeling step 500 is a new reconfiguration sub-step 502 taking into account the new region to be peeled.

[0083] Therefore, sub-steps 502 to 506 are repeated until weld bead 26 is completely peeled off.

[0084] The configuration change sub-step 502 in this use case of the present invention is as follows: - longitudinal displacement of the movable support 11, and / or - changing the orientation of the laser stripping head 52, and / or - Changing the height of the laser peeling head 52 relative to the sealing film 2 Corresponds to.

[0085] These reconfiguration sub-steps are performed without projecting the laser beam 6, i.e., "empty", thereby reducing the stripping time compared to prior art techniques.

[0086] In other uses of the present invention, such reconfiguration substep 502 may involve other types of movement, for example transverse movement of movable equipment and / or processing tools.

[0087] Therefore, the peeling method is performed sequentially, and between each peeling sequence of the regions to be peeled, the configuration change step 502 is performed. Successive peeling sequences do not necessarily correspond to adjacent regions of the sealing film 2.

[0088] For example, during step 100, the movable support 11 passes continuously in the longitudinal direction L in the direction 55 along a predetermined path on the rail 3 at the edge of the sealing plate 2-1. This continuous passing is performed empty. Then, the dividing step 400 is performed by the stationary generator 1 of the peeling device 5. In step 500, the peeling device 5 performs a first run in the direction 59, during which it peels off all of the slopes 242 of the corrugations 24 it encounters and the first halves 221 of the flat regions 22 it encounters (see FIG. 5 ). Then, the peeling device 5 performs a second run in the direction 55, during which it peels off all of the slopes 241 of the corrugations 24 it encounters and the second halves 222 of the flat regions 22 it encounters.

[0089] The fact that the peeling device 5 first performs a first run, during which it peels the slope 241 of the corrugations 24, which is a slope rising in the direction of the first run 59, and then performs a second run, during which it peels the slope 242 of the corrugations 24, which is a slope rising in the direction of the second run 55, makes it possible to increase the speed of performing the peeling method, in particular the rotation time of the laser peeling head 52. In fact, if the peeling device 5 peels each corrugation 24 in a single unidirectional run along the rail 3, the laser peeling head 52 would have to perform several rotations of 140°, which is not the case in this example of the peeling method according to the invention. The peeling method according to this example is optimized with respect to the longitudinal movement and rotation of the laser peeling head 52 in order to equally divide the predetermined path into separation areas.

[0090] Naturally, other variants of the embodiment of the peeling method according to the invention are also possible, in particular, as an alternative, the corrugations 24 of the sealing film 2 are simply divided into four areas to be peeled, and then each of the inclined faces 241, 242 is divided into two areas to be peeled, one covering the foot of the inclined face 241, 242 and the other covering the crest of the inclined face 241, 242. In this case, the areas to be peeled corresponding to the foot of the corrugation are peeled with a laser beam angle of 70° with respect to the vertical direction V, and the areas to be peeled corresponding to the crest of the corrugation are peeled with a laser beam angle of 50° with respect to the vertical direction V.

[0091] 10, a method for controlling the sealing film 2 will now be described, which includes an initial step 100 of passing the position sensor 12 and a step 200 of generating a profile of at least a portion of the sealing film 2, the method for generating the profile described above in relation to FIGS.

[0092] The next step 700 of the control method is the comparison of the distances obtained using the profile generated in the generating step 200 with the corresponding distances of a pre-registered template of the sealing membrane portion 2. These distances can be, for example, distances measured on the sealing film 2 and corresponding distances obtained from a pre-registered template, - or the distance measured in the vertical direction V between a point on the reference axis (e.g., rail 3) and the sealing membrane, and the corresponding distance from a pre-registered template. Corresponds to.

[0093] In this comparison, the difference between the distance obtained using the generated profile and the corresponding distance of the pre-registered template is calculated. The difference calculated in step 700 is then compared with a predetermined threshold value, for example 1 mm or 2 mm, which is used to detect incorrect positioning of the corrugations 24 on the sealing membrane 2 or deformation of the corrugations 24 on the sealing membrane 2.

[0094] In the next step 800, if the absolute value of the distance calculated in step 700 is less than a predetermined threshold, steps 700 and 800 are repeated for another distance of the profile generated in step 200 and another distance of the pre-recorded template until the generated profile is fully implemented or an anomaly is detected in step 800.

[0095] On the other hand, if the absolute value of the distance calculated in step 700 is greater than a predetermined threshold, an abnormality in the sealing film 2 is detected, which triggers, for example in step 800, a step of recording the abnormality and / or a step of sending a warning to the user interface.

[0096] Naturally, the invention is not limited to the examples described here, and many adjustments may be made to these examples without departing from the scope of the invention.

Claims

1. A method for processing a sealing film (2) suitable for a tank intended to contain a gas in liquid state, using a processing apparatus (5, 7) for processing the sealing film (2), wherein the processing apparatus (5, 7) comprises a movable device (70, 11) and at least one processing tool (72, 52) attached to the movable device (70, 11), the processing method comprising the step (600, 500) of processing the sealing film (2) by the processing tool (72, 52) along a predetermined path of the movable device (70, 11), the processing method, - A preliminary step (200) of generating a profile of at least a portion of the sealing film (2) for the predetermined path using a movable support (11) equipped with a position sensor (12), and the passage (100) of the position sensor over the sealing film (2), during the passage (100), - A substep (102) of determining the distance (d) between the reference point of the position sensor and at least one point of the sealing film portion (2), - A substep (104) to record the determined distance (d), - A substep (106) of moving the movable support (11), This is repeated, passing (100) and Includes, In a method in which the generation (200) of the profile of the sealing film portion (2) correlates with the distance (d) recorded during the recording substep (104), The aforementioned processing method is: - A dividing step (400) in which, according to the profile generated during the generating step (200), the predetermined path is divided into processing areas (243, 244, 245, 246, 247, 248) of the sealing film (2), wherein at least one modification (502) of the configuration of the movable device (11) and / or the processing tool (52) is required between the processing areas, - During the processing step, at least one substep (502) is performed to change the configuration of the movable device (11) and / or the processing tool (52) between two of the processing areas, A method for processing, further comprising:

2. The sealing film (2) comprises a first sealing plate and a second sealing plate arranged in contact with each other, the sealing film portion (2) is the edge of the first sealing plate (2-1), the edge of the first sealing plate (2-1) is positioned on a part of the edge of the second sealing plate (2-2), the passage (100) of the position sensor (12) is also suitable for determining the distance (d) between a point on the edge of the second sealing plate (2-2) and the reference point of the position sensor, and the generating step (200) generates a profile of the edge of the first sealing plate (2-1) and a profile of the edge of the second sealing plate (2-2), the processing method according to claim 1.

3. The processing method according to claim 1 or 2, wherein the position sensor (12) is a scanning laser sensor, the substep (102) for determining distance (d) corresponds to a substep (102) for determining multiple distances (d) for the exact same position on the movable support (11), and the generating step (200) generates a three-dimensional profile of the sealing film portion (2).

4. The processing method according to claim 1 or 2, wherein each processing area (243, 244, 245, 246, 247, 248) corresponds to the processing sequence of the processing steps (600, 500), and no modification (502) of the configuration of the movable device (11) and / or the processing tool (52) is required during the processing steps.

5. The processing method according to claim 1 or 2, wherein, following the division step (400), the processing areas (243, 244, 245, 246, 247, 248) are ordered according to the processing order.

6. The processing method according to claim 5, wherein the processing sequence corresponds to discontinuous processing of the sealing film (2).

7. The processing method according to claim 1 or 2, wherein the configuration change substep (502) generates displacement of the movable device (11) and / or the processing tool (52) and interrupts the processing during the configuration change substep (502).

8. The processing method according to claim 1 or 2, wherein the processing corresponds to an operation of peeling off the weld bead (26) at the level of the two sealing plate edges (2-1, 2-2) of the sealing film (2), the sealing film portion (2) is the edge of the first sealing plate (2-1), and the edge of the second sealing plate (2-2) is arranged in contact with the edge of the first sealing plate (2-1).

9. The processing method according to claim 1 or 2, wherein the sealing film (2) comprises a corrugated portion (24), the corrugated portion (24) forming a grid on the sealing film (2), the processing tool (52) is a laser peeling head positioned on a predetermined path for peeling off a weld bead (26), and a configuration change substep (502) is triggered to position the collision point (63) of a laser beam (6) projected by the laser peeling head to a region (243, 244) located at the base of the corrugated portion (24) of the sealing film (2).

10. The processing method according to claim 9, wherein the processing area is configured to enable peeling using only laser scanning over each of the processing areas (243, 244, 245, 246, 247, 248) without any additional movement of the movable device (11) or the laser peeling head.

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