Apparatus for laser cutting a workpiece and apparatus for collecting the generated elements, and method of use - Patent Application 20070122997

Abstract

An apparatus for laser cutting a workpiece and collecting elements generated therefrom, as well as a method of use. The invention relates to an apparatus for capturing and transporting elements generated during cutting of a workpiece (4) with a power laser, the workpiece having, in particular, a radioactive element, and the apparatus comprises a power laser capable of cutting the workpiece, a laser irradiation head (1) for emitting a laser beam (2), an exhaust air stream (3), and a chamber for capturing elements generated during the cutting, removably connected to the laser irradiation head (1). The chamber comprises: a) a recess (5) with an exhaust section (7); and b) an air nozzle (6) capable of emitting a compressed air stream (8) toward the exhaust section (7) of the recess (5). The invention also relates to a method for laser cutting a workpiece (4), collecting elements generated during cutting of the workpiece, and using the apparatus.

Description

[Technical Field]

[0001] The present application relates to the field of nuclear power, and more particularly to the field of decommissioning of nuclear facilities. The present invention relates to an apparatus for capturing and transporting elements produced during cutting of a workpiece with a power laser, said workpiece comprising, in particular, radioactive elements. The present invention also relates to a method for laser cutting a workpiece and recovering elements produced during cutting of the workpiece, said workpiece comprising, in particular, radioactive elements. [Background technology]

[0002] Demolition involves the discharge of radioactive materials and waste, the removal of existing equipment, and the sanitization and dismantling of buildings at the end of the life of a nuclear facility or at its final shutdown. It is a very long-term industrial project, with safety reviews carried out at each stage to ensure that the risks of the work are controlled.

[0003] The decommissioning of a nuclear facility requires the implementation of highly safe operating conditions to avoid contamination of the environment, people directly or indirectly involved in the decommissioning, or even people in the immediate vicinity or distant from the decommissioning site. Therefore, controlling and reducing contamination risks is one of the important objectives when decommissioning a nuclear facility.

[0004] This dismantling is also necessary after nuclear accidents, such as the Fukushima site, where dismantling is currently underway. One of the key steps in the dismantling of nuclear facilities at Fukushima corresponds to the removal of depleted fuel from the reactor core (Le corium de Fukushi de Fukushima: Formation, Itatue · R&D vue sa recuperation, Christophe Journeau, Damien Roulet, 16th International Conference on Fluid Mechanics, CNRS, Centrale Supelec, Paris Saclay University, RNSI, Sep 2018, Dourdan, France). These fuels, also known as "corium," correspond to the depletion of the reactor core and are typically detected and monitored by robots sent into the reactor containment vessel. Corium originates from the meltdown of the reactor core and consists of the mass of fuel and fuel-supporting structural material in the tanks that melt and mix during normal reactor operation and are kept molten by the release of residual power due to the radioactive decay of fission products trapped in the corium ("Les de fusion du coeur des reacteurs nucleaires de puissance", Didier Jacquemain, Radioprotection and Nuclear Safety Institute, 2013, p. 70). The presence of large amounts of corium in reactors at nuclear facilities such as those at Fukushima is a major source of radioactive risk to operators and the environment. It is therefore essential to reduce this risk, which requires its removal and storage under stable and controlled conditions.

[0005] Extracting the corium requires cutting it into pieces with a view to its removal and conditioning, followed by cooling in metal drums on the plant site before final storage. Cutting the corium presents several challenges, given that it is a heterogeneous and complex material, can be present in different forms and at different locations within the reactor block, is highly radioactive (on the order of 10 to 1,000 Gy / h), requiring the intervention of remote means for all operations performed within the containment vessel, and is difficult to access because the interior of the reactor building is highly contaminated, partially destroyed, or partially submerged to ensure that fuel cooling is still present. Among the many existing cutting techniques, such as coring, milling, shearing, plasma cutting, or waterjet cutting, laser cutting is a possibility envisioned, especially for the Fukushima site, due to its cutting capabilities, ease of remote implementation, and robustness in this type of environment.

[0006] However, to limit the risk of these radioactive elements dispersing within the containment vessel during laser cutting, efficient solutions are needed to limit the spread of aerosols, gases, and slag formed as secondary waste from the laser cutting process and to efficiently collect them. Indeed, the lack of measures to collect the secondary radioactive elements generated during cutting could lead to their suspension within the containment vessel, which would pose a risk of contamination of the immediate or distant environment by corium, especially if the vessel were to lose full or partial sealing during an earthquake, for example. A simulation of laser cutting of corium was carried out by a French research group on a specific vessel called DELIA, developed by the Atomic Energy Commission, which allowed them to collect and characterize part of the aerosols generated (Peillon et al., "Aerosol Characterization and Particle Scrubbing Efficiency of Underwater Operations During Laser Cutting of Steel Components for the Dismantling of Nuclear Facilities," Aerosol and Air Quality Research, 2017, pp. 1463-1473). The vessel has an extraction chimney connected to an aerosol characterization line made of a cylindrical stainless steel pipe, where the airflow is maintained at 100 m / h and equipped with two sampling probes connected to two different filters. The vessel also has a chimney that allows air to be recirculated within the vessel, equipped with a HEPA filter that collects elements not captured by the extraction chimney. This solution therefore allows the elements generated during the laser cutting of the corium to be collected as close as possible to the cutting area, ensuring optimal collection of said elements and thus preventing any risk of a possible loss of tightness of the vessel.

[0007] It is understood that in order to limit the risk of dispersion of these elements and contamination of the environment and personnel, it is necessary to have a solution to efficiently collect the secondary radioactive elements of any size that are produced by laser cutting of corium, regardless of the type of container in which the cutting is performed.

[0008] More generally, there is a need for a solution that allows for the efficient collection of secondary elements of any size generated by laser cutting of components containing radioactive elements. In fact, the only existing solutions to date consist of carrying out the cutting operation in a sealed, ventilated container equipped with a filter. However, as mentioned above, these solutions do not allow the collection of elements generated during cutting, especially radioactive elements, as close as possible to the cutting area, ensuring optimal collection of said elements as well as avoiding their suspension in the container and thus limiting any risks associated with a possible loss of tightness of the container. Summary of the Invention [Problem to be solved by the invention]

[0009] A first object of the present invention relates to a device for laser cutting of parts and for recovering elements produced by said cutting, said device comprising: - a power laser capable of cutting the workpiece (4), said power laser having a laser irradiation head (1) capable of emitting a laser beam (2) and an exhaust airflow (3); - a chamber detachably connected to the laser irradiation head (1) for capturing elements resulting from cutting, the chamber having a recess (5) in the chamber and an air blowing nozzle (6) capable of releasing a compressed air flow (8) in the direction of an exhaust part (7) of the recess (5).

[0010] A second object of the present invention relates to a method for laser cutting a workpiece and collecting the elements produced by said cutting, using a device according to any one of claims 1 to 8: - the workpiece (4) to be cut is arranged in the axis of the laser beam (2) emitted by the irradiation head (1) of the power laser; - a chamber for capturing elements generated by cutting is detachably connected to the laser irradiation head (1), the chamber having a recess (5), the recess (5) having a) an exhaust part (7) and b) an air blowing nozzle (6), the air blowing nozzle (6) being capable of emitting a compressed air flow (8) in the direction of the exhaust part (7); - said laser projection head (1) emits a laser beam (2) coupled into the exhaust airflow (3); The blower nozzle (6) emits a compressed air flow (8) in the direction of the exhaust section (7) of the recess (5), and can direct the elements generated during cutting in the direction of the exhaust section (7). [Means for solving the problem]

[0011] To meet the needs of the prior art, the applicant proposes an apparatus for laser cutting components and collecting elements, particularly radioactive elements, generated by this cutting. The apparatus proposed by the present invention advantageously allows cutting components containing radioactive elements, which can be, for example, corium, while ensuring efficient collection of secondary elements generated by this cutting as close as possible to the cutting area. The apparatus and the method for using this apparatus proposed by the present invention allow limiting the dispersion of secondary elements generated during cutting within and outside the cutting environment, thus limiting the possible risk of radioactive contamination. The proposed invention therefore limits or even avoids the dispersion of secondary elements, particularly radioactive elements, generated during cutting within the containment vessel in which it is implemented. This advantageously limits the risk of secondary contamination in the event of a total or partial loss of the vessel's airtightness, but also reduces stress on the vessel's extraction line, limits the vessel's holding operations, and extends the vessel's lifespan. Preferably, the present invention is intended to be implemented in cutting and / or dismantling operations that require the implementation of remote operating means.

[0012] Accordingly, a first aspect of the present invention is an apparatus for laser cutting a workpiece and recovering elements produced by the cutting, the apparatus comprising: - a power laser capable of cutting the workpiece (4), said power laser having a laser irradiation head (1) capable of emitting a laser beam (2) and an exhaust airflow (3); - A chamber (5) detachably connected to the laser irradiation head (1) for capturing elements resulting from cutting, the chamber (5) having a recess (5) and an air blowing nozzle (6) capable of releasing a compressed air flow (8) in the direction of an exhaust part (7) of the recess (5).

[0013] In the present invention, "elements produced by laser cutting of a part" refers to material elements that are released from the part during laser cutting of said part and are produced as a result. The nature of the elements produced will depend on the nature of the material of the part being cut.

[0014] The elements produced by laser cutting are of variable size, and these elements can be, for example, particles, dust, fumes, slag, or aerosols. Aerosols have sizes, for example, comprised between 100 nm and 10 μm. Dust has sizes, for example, comprised between 10 μm and 500 μm. Slag has sizes, for example, comprised between 500 μm and 10 mm. If the cut member is a part containing a radioactive element, for example, if the part is corium, all or part of the elements produced by laser cutting of the part are radioactive elements.

[0015] In the present invention, the power laser implemented includes a "laser irradiation head" comprising a coherent light source generating a power laser beam, an optical module for focusing the beam and directing it along at least one axis on the surface of the workpiece to be cut, and a blowing means capable of emitting an exhaust airflow corresponding to the compressed airflow. In particular, the laser irradiation head realized in the device according to the present invention includes a blowing means. More specifically, the blowing means configured by the irradiation head can emit an exhaust airflow, thereby directing the elements generated during laser cutting toward the exhaust portion of the recess of the chamber. According to a first aspect, the blowing means configured by the laser irradiation head is arranged around the light source and the optical module. According to a second aspect, the blowing means configured by the irradiation head is arranged on a module held by the irradiation head, the module forming a part of the irradiation head. According to each of the above aspects, the blowing means emits a compressed airflow, called the exhaust airflow, in the direction of the point of impact of the laser beam on the part to be cut. Preferably, the blowing means configured by the laser irradiation head is an air nozzle, which may be connected to an air compressor. The power laser realized in the device according to the invention is capable of cutting parts depending on the laser realization parameters such as the wavelength of the laser beam, the power of the laser beam and the flow rate of the exhaust air stream.

[0016] Preferably, the irradiation head of the power laser realized by the present invention irradiates a laser beam having a wavelength comprised between 650 and 1090 nm, preferably between 1030 and 1070 nm. In this case, the laser beam emitted by the irradiation head preferably has an output comprised between 4 and 14 kW.

[0017] In particular, in the present invention, the exhaust airflow emitted by the blowing means constituted by the irradiation head has a flow rate comprised between 100 and 2000 liters / minute.

[0018] According to a particularly preferred embodiment, the power laser irradiation head irradiates a laser beam with a wavelength of 1030 to 1070 nm having an output of 4 to 14 kW and emits an exhaust airflow with a flow rate of 400 to 2000 liters / min.

[0019] The capture chamber implemented in the device according to the present invention is capable of capturing and collecting elements produced by laser ablation. "Capable of capturing and collecting elements produced by laser ablation" refers to the fact that the chamber captures and collects 70-100%, preferably 80-100%, more preferably 90-100%, and even more preferably 95-100% of the elements produced. Preferably, "capable of capturing and collecting elements produced by laser ablation" refers to the fact that the chamber captures and collects 80-100%, more preferably 90-100%, and even more preferably 95-100% of the aerosol produced.

[0020] In the device according to the invention, the capture chamber is removably connected to the laser irradiation head, which ensures that the chamber can be removed to retain it, clean it or even replace it if necessary. In each case, "connected to the laser irradiation head" refers to the fact that the capture chamber is retained and held in the laser irradiation head.

[0021] The exhaust of the recess allows the elements produced during laser cutting to pass in the direction of a collection and transport system, to which the exhaust is directly or indirectly connected.

[0022] The blowing nozzle provided in the capture chamber is connected to an air compressor so as to discharge a compressed air flow. The flow rate of the compressed air discharged by the blowing nozzle according to the present invention is 100 to 2000 liters / minute, preferably 500 to 1000 liters / minute.

[0023] The blowing nozzle contained in the capture chamber implemented in the device according to the invention is arranged to deflect the elements produced by the laser cutting towards the outlet from the recess. In the present invention, the blowing nozzle formed by the capture chamber is not positioned on the axis of the laser beam emitted by the laser irradiation head.

[0024] According to one particular embodiment of the invention, the compressed air flow emitted by the blowing nozzle can contain a lubricating composition to lubricate the recess and extend its service life or to facilitate the transport of elements generated by cutting in the direction of the exhaust of the recess.

[0025] The combination of the exhaust air flow emitted by the blowing means constituted by the laser irradiation head and the compressed air flow emitted by the blowing nozzle constituted by the capture chamber, which may be coupled to the lubricating composition, can advantageously minimize the air supply required in the system for collecting and transporting the elements generated by the cutting.

[0026] In particular, in the device according to the present invention, the exhaust section of the recess communicates with a system for collecting and transporting the elements generated by the laser cutting. The system for collecting and transporting the elements generated by the cutting includes an extraction duct, an extraction fan possibly connected to one or several pneumatic conveyors, and one or several medium-, high-, and / or very high-efficiency filters. The air conveyors allow elements generated during the cutting that would otherwise have settled to be resuspended in the system duct. The extraction fan ensures a high airflow velocity containing the elements generated by the laser cutting in the collection and transport system, more particularly in the extraction duct of the system. The velocity of the airflow containing the elements generated by the laser cutting in the collection and transport system is preferably comprised between 17 and 35 meters per second. This high velocity advantageously ensures that all the generated elements pass through the extraction duct as well as the filter and do not accumulate in the collection and transport system.

[0027] Preferably, the collection and transport system comprises several standard, high-efficiency and / or very high-efficiency filters. Among the medium- or high-efficiency filters, there are mechanical effect separator filters that allow filtering out generated elements with a size greater than 5 μm, such as dust and slag. When a medium / high-efficiency mechanical effect separator filter is implemented, it is advantageously connected to a compartment that allows collecting said elements. A very high-efficiency filter, such as a HEPA filter, allows filtering out all generated elements that would not have been filtered before, such as small aerosols.

[0028] In one particular embodiment of the present invention, the collection and transport system comprises an extraction duct, at least one fan possibly connected to one or several pneumatic conveyors, a mechanical effect separator filter and a very high efficiency filter. In this embodiment, the medium / high efficiency filter is arranged upstream of the very high efficiency filter. Preferably, in this embodiment, the medium / high efficiency filter is associated with a compartment that allows the filtered elements, i.e. elements with a size greater than 5 μm, such as slags, to be collected.

[0029] The recess of the capture chamber according to the invention can be made of, for example, stainless steel, steel, titanium, graphite, tungsten carbide, steel coated with special coatings used in the welding industry such as zirconia, anti-adhesion baths (anti-spatter) used in the welding industry, or alloys of metals such as nickel, chromium and iron in high proportions, such as INCONEL® 718 made of NiCr19Fe19Nb5Mo3 alloy, INCONEL® 600 made of Ni72Cr14Fe6 alloy, INCONEL® 625 made of NiCr22Mo9Nb alloy. According to one particular embodiment, the recess is made of a material selected from NiCr19Fe19Nb5Mo3 alloy, stainless steel, titanium, or steel coated with special coatings used in the welding industry such as graphite, tungsten carbide, zirconia, anti-adhesion baths (anti-spatter) used in the welding industry. The capture chamber according to the invention, and in particular the recess, can comprise a coating that makes it possible to reduce the adhesion of the elements produced, for example to improve its robustness, to extend its lifespan and / or to improve the collection and transport of said elements. This coating can be, for example, a lubricating composition.

[0030] According to a particular aspect of the invention, the exhaust of the recess has a curved shape. More specifically, the curved shape of the recess is located between the entrance of the recess and the collection and transport system at the level of the exhaust of the member. This curved shape advantageously makes it possible to limit the total space requirement of the system consisting of the capture chamber and the laser irradiation head.

[0031] The thickness of the material to be cut can be varied from a few mm to 200 mm. Depending on the thickness, the cutting speed varies from 1 cm / min to 20 cm / min. [Brief explanation of the drawings]

[0032] [Figure 1]1 shows a device according to the invention for through-cutting a workpiece to be cut, showing a laser irradiation head (1) of a power laser capable of emitting a laser beam (2) and an exhaust air flow (3) in the direction of the workpiece to be cut (4), and a chamber detachably connected to the laser irradiation head for capturing the elements produced by the cut, said chamber comprising a recess (5) having a) an exhaust (7) and b) an air nozzle (6) capable of emitting a compressed air flow (8) in the direction of the exhaust (7) of the recess (5). [Figure 2] 2 shows an apparatus for non-penetratingly cutting a workpiece. It comprises a laser irradiation head (1) of a power laser capable of emitting a laser beam (2), an exhaust airflow (3) via a blowing means (14) in the direction of the part to be cut (4), and a chamber detachably connected to the laser irradiation head for capturing elements produced by the cutting, the chamber comprising a recess (5) having an exhaust section (7) and an air blowing nozzle (6) capable of releasing a compressed air flow (8) in the direction of the exhaust section (7) of the recess (5). DETAILED DESCRIPTION OF THE INVENTION

[0033] In one particular embodiment of the invention, the device is a through-cutting laser device, wherein the capture chamber is removably connected to the laser irradiation unit and positioned on the side of the part (4) to be cut, the part (4) being the part opposite to the part to which the laser beam (2) is applied, and the laser beam (2) is applied such that the capture chamber is positioned at a distance of between 10 mm and 100 mm from the part (4) to be cut.

[0034] As shown in Figure 1, this embodiment comprises a laser irradiation head (1) capable of irradiating a laser beam (2), an exhaust airflow (3) directed toward a workpiece (4) to be cut, and a chamber detachably connected to the laser irradiation head for capturing elements generated by cutting. The chamber comprises a recess (5) with an exhaust section (7) and an air blowing nozzle (6) capable of releasing a compressed air flow (8) in the direction of the exhaust section (7).

[0035] FIG. 1, which illustrates this particular embodiment, also shows in the recess (5) a first orifice (9) positioned at the entrance of the member through which the laser beam and the exhaust airflow emitted by the laser irradiation head can pass, a second orifice (10) aligned with the first orifice and through which the laser beam can pass, a third orifice (11) in communication with the exhaust section (7), and a fourth orifice (12) in communication with a blower nozzle (6) capable of emitting a compressed airflow (8) in the direction of the third orifice (11).

[0036] In this configuration, the laser beam (2) emitted by the laser irradiation head (1) melts the workpiece (4) to be cut, and the elements produced by the laser cutting are projected into the recess by the exhaust air flow (3) emitted by said irradiation head on the side of the workpiece opposite to the part hit by the laser beam (2). A compressed air flow (8) emitted by the blower nozzle (6) makes it possible to deflect the air flow containing the elements towards the exhaust part (7) of the recess (5) which is connected to a system for collecting and transporting these elements.

[0037] More precisely, when the device according to the invention is used for through-cutting of a workpiece, the laser beam passes through the workpiece and the capture chamber is arranged on the rear face of the workpiece to be cut, i.e. on the face opposite to the face on which the laser beam is applied. More precisely, in this embodiment, the recess is arranged opposite the rear face of the cut.

[0038] Preferably, in this embodiment, the capture chamber and in particular the recess is located at a distance of between 10 mm and 50 mm from the workpiece to be cut, which distance allows the capture chamber to be located as close as possible to the workpiece to be cut, collecting the maximum amount of elements generated during cutting, while the capture chamber, in particular the recess, is not too close to the workpiece to be cut and is not damaged by the heat of the workpiece to be cut due to the application of the laser beam on said workpiece.

[0039] In this embodiment, the laser irradiation head includes a blowing means, preferably a blowing nozzle, arranged around the light source and the optical module, which emits a compressed air flow in the direction of the point of impact of the beam on the member, i.e., in the same direction as the laser beam.

[0040] In particular, in this embodiment, the recess (5) comprises: a first orifice (9) arranged at the entrance of the member (4) and allowing the laser beam (2) emitted by the laser irradiation head (1) and the exhaust airflow (3) to pass through; a second orifice (10) aligned with the first orifice (9) and allowing the laser beam (2) to pass through; - a third orifice (11) communicating with an exhaust (7) which communicates with a system for collecting and transporting elements produced during cutting; - A fourth orifice (12) is provided in communication with the blowing nozzle (6) and is capable of discharging the compressed air flow (8) in the direction of the third orifice (11). Preferably, the first orifice (9) has a diameter comprised between 40 mm and 120 mm depending on the type of cutting, the second orifice (10) has a diameter comprised between 20 and 60 mm, and the exhaust section (7) has a diameter comprised between 35 and 60 mm and rises in the direction of the laser irradiation head. The fourth orifice (12) is located between the first orifice (9) and the third orifice (11), and the third orifice (11) communicates with the exhaust section (7) and is located between 10 mm and 50 mm from the first orifice (9).

[0041] More particularly, the fourth orifice (12) forms an angle comprised between 45 and 90 degrees, preferably 70 degrees, with respect to the axis formed by the laser beam (2) emitted by the laser projection head (1).

[0042] Even more particularly, the fourth orifice of the recess is positioned to form an angle comprised between 0 and 90 degrees with respect to the third orifice communicating with the exhaust.

[0043] In another embodiment of the device according to the invention, the device is a device for non-penetrating laser cutting of a workpiece, the capture chamber being detachably connected to the laser irradiation head (1) and positioned on the side of the workpiece (4) to be cut corresponding to the part to which the laser beam (2) is intended to be applied.

[0044] This embodiment is illustrated in Figure 2, in which a laser beam (2) is emitted by the laser irradiation head (1) of a power laser in the direction of the workpiece (4) to be cut, and an exhaust air flow (3) is emitted via a blowing means (14). A chamber is detachably connected to the laser irradiation head and captures the elements produced by the cut. The chamber comprises a) an exhaust (portion 7) and b) a recess (5) with a blowing nozzle (6) capable of emitting a compressed air flow (8) in the direction of the exhaust portion (7) of the recess (5).

[0045] In this configuration, the laser beam emitted from the laser irradiation head melts the portion to be cut, and the blowing means (14) and the blowing nozzle (6) are attached to a module (13) held by the irradiation head. In this embodiment, the laser beam does not pass through the material to be cut. In particular, in this embodiment, the recess (5) has an opening at the bottom opposite to the cutting location. Preferably, this opening has a diameter of 10 mm to 50 mm.

[0046] In particular, in this embodiment, the exhaust section (7) of the recess (5) is directly connected to the laser irradiation head (1), and the blower nozzle (6) is connected to the head via a module (13) held in the laser irradiation head (1).

[0047] In this embodiment, the laser irradiation head includes a blowing means arranged on a module held by the irradiation head, the module forming a part of the irradiation head. The blowing means emits a compressed air flow, called an exhaust air flow, in the direction of the impact point of the laser beam on the cutting portion. Preferably, the blowing means configured by the laser irradiation head is a blowing nozzle that may be connected to an air compressor.

[0048] In this embodiment, the capture chamber forms a closed assembly at the level of the laser irradiation head and is open to the material to be cut, in particular around the periphery of said head. Preferably, this closed assembly comprises a module held on the irradiation head, on which module are arranged the blowing means constituted by the laser irradiation head and the blowing nozzle constituted by the capture chamber.

[0049] In this particular embodiment, the distance between the capture chamber and the workpiece to be cut is determined by the distance between the irradiation head and the workpiece to be cut. The recess and the exhaust of the blowing nozzle are preferably located 10-40 mm from the workpiece to be cut, and preferably about 20 mm from the workpiece.

[0050] More specifically, according to this embodiment, the blowing nozzle (6) is arranged so that the compressed air flow (8) emitted by said nozzle makes an angle comprised between 70 and 135 degrees with respect to the axis formed by the laser beam (2) emitted by the laser irradiation head (1). More precisely, the exhaust air flow is emitted by a blowing means constituted by the laser irradiation head.

[0051] More particularly, according to this embodiment, the vent portion (7) of the recess (5) forms an angle of between 30 and 70 degrees, preferably 30 degrees, with respect to the piece (4) to be cut.

[0052] According to one particular aspect of this embodiment, the blower nozzle is positioned to form an angle of between 70 degrees and 135 degrees, preferably 120 degrees, with respect to the axis formed by the flow of the exhaust airflow emitted by the laser irradiation head, and the exhaust portion of the recess is positioned to form an angle of between 30 degrees and 70 degrees, preferably 30 degrees, with respect to the workpiece to be cut.

[0053] Another aspect of the present invention relates to a capture chamber that can be removably connected to a laser irradiation head, said chamber comprising: a) a recess including an exhaust section; and b) a blowing nozzle that can emit a compressed air flow in the direction of the exhaust section of said recess.

[0054] In a first particular embodiment of this means, the capture chamber is intended to be removably connected to the laser irradiation head and to be positioned on the side of the material to be cut corresponding to the one to which the laser beam is intended to be applied.

[0055] According to this particular embodiment, the exhaust portion of the recess is directly connected to the laser irradiation head, and the blowing nozzle is connected to the laser irradiation head via a module held on said head, and said nozzle is capable of emitting an air flow in the direction of the exhaust portion of the recess.

[0056] According to this embodiment, the irradiation head comprises blowing means capable of emitting a compressed air flow, called discharge air flow, in the direction of the impact point of the laser beam on the workpiece to be cut, said blowing means being arranged on a module held by the irradiation head. Preferably, the blowing means constituted by the laser irradiation head is a blowing nozzle which may be connected to an air compressor.

[0057] In this embodiment, the capture chamber forms a closed assembly at the level of the laser irradiation head, in particular around said head, and is open to the workpiece to be cut. Preferably, this closed assembly comprises a module held on the irradiation head, on which module are arranged the blowing means constituted by the laser irradiation head and the blowing nozzle constituted by the capture chamber.

[0058] According to this particular embodiment, the blowing nozzle is positioned to form an angle of between 70 and 135 degrees, preferably 120 degrees, with respect to the axis formed by the laser beam emitted by the laser projection head. More particularly, the exhaust portion of the recess forms an angle of between 30 and 70 degrees, preferably 30 degrees, with respect to the workpiece to be cut.

[0059] In a second particular embodiment of this object, the capture chamber is removably connected to the laser irradiation head so as to be positioned on the side of the member to be cut opposite the member to which the laser beam is intended to be applied, the capture chamber being positioned at a distance comprised between 10 mm and 100 mm from the side of the member to be cut opposite the member to which the laser beam is intended to be applied.

[0060] According to this particular embodiment, the recess of the capture chamber comprises: a first orifice disposed at the entrance of the member, the first orifice being capable of passing the laser beam emitted by the laser irradiation head and the emitted airflow; a second orifice aligned with the first orifice, the second orifice being capable of passing a laser beam; a third orifice communicating with the exhaust and with a system for collecting and transporting elements produced during cutting; - A fourth orifice communicating with the blower nozzle, capable of discharging a compressed air flow in the direction of the third orifice, the third and fourth orifices being arranged on opposite sides of the recess.

[0061] According to this particular embodiment, the fourth orifice of the recess of the capture chamber forms an angle comprised between 45 and 90 degrees with respect to the axis formed by the laser beam (2) emitted by the laser projection head.

[0062] In this embodiment, the laser irradiation head comprises a blowing means, preferably a blowing nozzle, arranged around the light source emitting the laser beam and the optical module of the laser irradiation head, and in this embodiment, the blowing means emits a compressed air flow in the direction of the point where the beam impinges on the member, i.e., in the same direction as the laser beam.

[0063] According to one preferred aspect of this embodiment, the trapping chamber is positioned slightly offset from the laser beam.

[0064] In both embodiments for this purpose, the exhaust of the recess communicates with a system for collecting and transporting the generated elements.

[0065] The recess of the capture chamber according to the invention can be made of, for example, stainless steel, steel, titanium, graphite, tungsten carbide, steel coated with special coatings used in the welding industry, such as zirconia, or alloys of metals containing high proportions of nickel, chromium, and iron, such as INCONEL® 718 made of NiCr19Fe19Nb5Mo3 alloy, INCONEL® 600 made of Ni72Cr14Fe6 alloy, or INCONEL® 625 made of NiCr22Mo9Nb alloy. According to one particular embodiment, the recess is made of a material selected from NiCr19Fe19Nb5Mo3 alloy, stainless steel, titanium, or steel coated with special coatings used in the welding industry, such as graphite, tungsten carbide, zirconia, and anti-adhesion baths (anti-spatter) used in the welding industry.

[0066] In particular, the exhaust portion of the recess has a curved shape.

[0067] All of the features relating to the capture chamber described above for the first aspect of the invention apply mutatis mutandis to this purpose.

[0068] A second aspect of the present invention is a method for using an apparatus according to the first aspect to laser cut a workpiece and collect elements produced by the cutting, the method comprising, in sequence: - the workpiece (4) to be cut is arranged in the axis of the laser beam (2) emitted by the irradiation head (1) of the power laser; - a recess (5) for detachably connecting a chamber for capturing elements generated by cutting to the laser irradiation head (1) and capable of releasing a compressed air flow (8) in the direction of the exhaust part (7) of the recess (5) consisting of a) an exhaust part (7) and b) an air blowing nozzle (6); - said laser projection head (1) emits a laser beam (2) coupled into the exhaust airflow (3); The blower nozzle (6) emits a compressed air flow (8) in the direction of the exhaust section (7) of the recess (5), and can direct the elements generated during cutting in the direction of the exhaust section (7).

[0069] In the method according to the present invention, the laser irradiation head emits an exhaust airflow corresponding to the compressed airflow via a blowing means configured by the head. According to a first aspect, the blowing means is arranged around the laser irradiation head, more specifically around the light source and optical module of the laser irradiation head. According to a second aspect, the blowing means is arranged on a module held by the irradiation head, the module forming part of the irradiation head. According to each of the above aspects, the blowing means emits an exhaust airflow in the direction of the impact point of the laser beam on the intended cutting portion.

[0070] In particular, in the method according to the present invention, the laser beam emitted by the irradiation head of the power laser has a wavelength comprised between 650 and 1090 nm, preferably between 1030 and 1070 nm, and more preferably has a power comprised between 4 and 14 kW.

[0071] Preferably, in the present invention, the exhaust airflow emitted by the irradiation head has a flow rate comprised between 100 and 2000 liters / minute. According to a particularly preferred embodiment, the irradiation head of the power laser emits an exhaust airflow having a wavelength of 1030 to 1070 nm, a power of 4 to 14 kW, and a flow rate of 400 to 2000 liters / minute.

[0072] In the method according to the invention, the exhaust in the recess allows the elements produced during laser cutting to pass in the direction of a system for collecting and transporting the elements, to which the exhaust is directly or indirectly connected. In the method according to the invention, the blowing nozzle emits a compressed air stream that deflects the elements produced by the laser cut in the direction of ejection of the recess.

[0073] A blower nozzle contained within the capture chamber is connected to an air compressor.

[0074] In particular, the blowing nozzle (6) emits a compressed air flow (8) having a flow rate between 400 and 2000 L / min.

[0075] According to one particular embodiment of the invention, the compressed air stream emitted by the blowing nozzle contains a lubricating composition for lubricating the recesses.

[0076] In the method according to the present invention, elements generated by laser cutting of a workpiece include particles, dust, fumes, slag, and aerosols. Aerosols have a size, for example, comprised between 100 nm and 10 μm. Dust has a size, for example, comprised between 10 μm and 500 μm. Slag has a size, for example, comprised between 500 μm and 10 mm.

[0077] According to one particular embodiment, the parts to be cut contain radioactive elements, and all or part of the elements produced by carrying out the method according to the invention are radioactive elements.

[0078] According to this method, the elements produced by laser cutting are biased towards the exhaust of the recess and then directed towards a collection transport system with which the exhaust communicates, i.e. is directly or indirectly connected.

[0079] The system for collecting and transporting the elements generated during the cutting process includes an extraction duct, an extraction fan possibly connected to one or several pneumatic conveyors, and one or several media, high-efficiency, and / or very high-efficiency filters. The presence of the pneumatic conveyor allows for the resuspension of particles in the duct, while the extraction fan ensures a high speed of the airflow containing the elements generated by the laser cutting in the collection and transport system, more particularly in the extraction duct of said system. The speed of the airflow containing the elements generated by the laser cutting in the collection and transport system is preferably comprised between 17 meters per second and 35 meters per second. This high speed advantageously ensures that all the generated elements pass through the extraction duct as well as the filter and do not accumulate in the collection and transport system.

[0080] In the method according to the invention, the generated elements are collected by a medium-, high- and / or very-high-efficiency filter, preferably a high- and / or very-high-efficiency filter, which is arranged in the extraction duct of the collection and transport system. According to a preferred embodiment of the method according to the invention, the generated elements having a size larger than 5 μm, such as slags and dust, are collected by a medium / high-efficiency filter, such as a mechanical effect separator, which is preferably connected to a compartment for collecting the elements, and the uncollected elements, such as dust and small aerosols, are collected and filtered by a very-high-efficiency filter.

[0081] According to a first particular embodiment, the present invention relates to a second means for a method for through-laser cutting of a workpiece, wherein a capture chamber is arranged on the side of the workpiece (4) opposite to the part to which the laser beam (2) is applied, at a distance of between 10 mm and 100 mm relative to the workpiece to be cut, the laser beam passing through the workpiece to be cut.

[0082] According to this embodiment, the capture chamber is arranged on the rear side of the workpiece to be cut, i.e., on the side opposite to the side irradiated with the laser beam. More precisely, in this embodiment, the recess, and in particular the first orifice of the recess, is arranged opposite the rear side of the workpiece to be cut.

[0083] Preferably, in this embodiment, the trapping chamber, in particular the recess, is located at a distance of 10 mm to 50 mm from the workpiece to be cut, which distance allows the trapping chamber to be located as close as possible to the workpiece to be cut so as to collect the maximum amount of elements generated during cutting, while not being too close to the workpiece to be cut and being damaged by the heat of the workpiece to be cut due to the application of the laser beam on said workpiece.

[0084] In this embodiment, the laser irradiation head preferably includes a blower, or a blower nozzle, arranged around the laser irradiation head, more particularly around the light source that emits the laser beam and the optical module of the laser irradiation head. In this embodiment, the blower emits a compressed airflow in the direction of the point where the beam hits the member, i.e., in the same direction as the laser beam.

[0085] According to this embodiment, the recess of the capture chamber implemented in the method comprises: - a first orifice arranged at the inlet of the member, the first orifice being able to pass the laser beam and the exhaust airflow emitted by the laser projection head; a second orifice aligned with the first orifice, the second orifice allowing the laser beam to pass; a third orifice corresponding to the exhaust and communicating with a collection and transport system capable of transporting the elements produced during the cutting; a fourth orifice communicating with the blowing nozzle and capable of emitting an air flow in the direction of the third orifice, the third and fourth orifices being arranged on opposite sides of the recess;

[0086] In particular, according to this embodiment, the compressed air flow (8) emitted by the blower nozzle (6) forms an angle between 45 degrees and 90 degrees, preferably 70 degrees, with respect to the axis formed by the laser beam (2) emitted by the laser irradiation head (1).

[0087] More specifically, the compressed air stream emitted by the blowing nozzle forms an angle comprised between 0 and 90 degrees with respect to the outlet of the member.

[0088] According to a second particular embodiment, the invention relates to a method according to the second aspect of the invention for non-through laser cutting of a workpiece, in which the capture chamber is arranged on the side of the workpiece (4) corresponding to the side to which the laser beam (2) is applied. According to this embodiment, the laser beam does not pass through the workpiece.

[0089] In this embodiment, the laser irradiation head includes a blowing means disposed on a module held by the irradiation head, the module forming a part of the irradiation head. The blowing means emits a compressed air flow, called an exhaust air flow, in the direction of the impact point of the laser beam on the cutting part. Preferably, the blowing means configured by the laser irradiation head is an air nozzle that may be connected to an air compressor. The exhaust air flow emitted by the blowing means can deflect the elements generated during the laser cutting along the axis formed by the laser beam in the direction of the exhaust of the workpiece.

[0090] In this embodiment, the capture chamber forms a closed assembly at the level of the laser irradiation head, in particular around said head, which assembly is open at the level of the workpiece to be cut. Preferably, this closed assembly comprises a module held on the irradiation head, on which module are arranged the blowing means constituted by the laser irradiation head and the blowing nozzle constituted by the capture chamber.

[0091] In particular, according to this embodiment, the compressed air flow (8) emitted by the blower nozzle (6) forms an angle between 70 degrees and 135 degrees, preferably 120 degrees, with respect to the axis formed by the laser beam (2) emitted by the laser irradiation head (1). Particularly, according to this embodiment, the exhaust portion 7 of the recess 5 forms an angle of 30 to 70 degrees with respect to the member 4 to be cut.

[0092] According to one preferred aspect of this embodiment, the recess of the capture chamber is provided with an exhaust port directly connected to the laser irradiation head, and the blowing nozzle is connected to the laser irradiation head via a module held on the head and emits a flow of air in the direction of the exhaust port of the recess.

[0093] According to this particular embodiment, the capture chamber is positioned at a distance from the workpiece to be cut that is determined by the distance between the laser head and the workpiece to be cut. The exhaust and blowing nozzle of the recess are preferably located at a distance of 10-40 mm from the workpiece to be cut, and preferably at a distance of about 20 mm from the workpiece.

Claims

1. 1. An apparatus for laser cutting a workpiece and recovering elements produced by the cutting, the apparatus comprising: - a power laser capable of cutting said workpiece (4), said power laser comprising a laser irradiation head (1) capable of emitting a laser beam (2) and an exhaust airflow (3); - a capture chamber detachably connected to the laser irradiation head (1) for capturing elements resulting from cutting, the capture chamber comprising a recess (5) with an exhaust section (7) and an air nozzle (6) capable of releasing a compressed air flow (8) in the direction of the exhaust section (7) of the recess (5); and The recess (5) is a first orifice (9) arranged opposite the member (4) and allowing the laser beam (2) emitted by the laser irradiation head (1) and the exhaust airflow (3) to pass through; a second orifice (10) aligned with the first orifice (9) and allowing said laser beam (2) to pass through; a third orifice (11) communicating with the exhaust (7), said exhaust communicating with a system for collecting and transporting elements produced during cutting; a fourth orifice (12) communicating with the blowing nozzle (6) and capable of releasing a compressed air flow (8) in the direction of said third orifice (11); An apparatus comprising:

2. 2. The apparatus for through-laser cutting of a workpiece according to claim 1, wherein the capture chamber is detachably connected to the laser irradiation head (1), the capture chamber is arranged on the opposite side of the part of the workpiece (4) to which the laser beam (2) is intended to be applied, and the capture chamber is arranged at a distance of 10 mm to 100 mm from the opposite side of the part of the workpiece (4) to which the laser beam (2) is intended to be applied.

3. 2. The device according to claim 1, wherein the fourth orifice (12) forms an angle comprised between 45 degrees and 90 degrees with respect to an axis formed by the laser beam (2) emitted by the laser irradiation head (1).

4. 1. An apparatus for non-penetrating laser cutting of a workpiece and recovering elements produced by the cutting, the apparatus comprising: - a power laser capable of cutting said workpiece (4), said power laser comprising a laser irradiation head (1) capable of emitting a laser beam (2) and an exhaust airflow (3); - a capture chamber detachably connected to the laser irradiation head (1) for capturing elements resulting from cutting, the capture chamber comprising: a recess (5) with an exhaust section (7); an air blowing nozzle (6) capable of discharging a compressed air flow (8) in the direction of the exhaust section (7) of the recess (5); and air blowing means (14) for discharging the exhaust air flow in the direction of the impact point of the laser beam on the cutting portion; and The capture chamber is detachably connected to the laser irradiation head (1), and the exhaust section (7) is arranged on the side of the workpiece (4) to be cut, corresponding to the portion to which the laser beam (2) is to be applied.

5. 5. The apparatus according to claim 4, wherein the exhaust section (7) of the recess (5) is directly connected to the laser irradiation head (1), and the blowing nozzle (6) is connected to the laser irradiation head via a module (13) held in the laser irradiation head (1).

6. 6. The device according to claim 5, wherein the blowing nozzle (6) is arranged so that the compressed air flow (8) emitted by the blowing nozzle forms an angle comprised between 70 degrees and 135 degrees with respect to an axis formed by the laser beam (2) emitted by the laser irradiation head (1).

7. 7. Device according to any one of claims 4 to 6, wherein the vent (7) of the recess (5) forms an angle comprised between 30 and 70 degrees with respect to the piece (4) to be cut.

8. 4. A method of using an apparatus according to any one of claims 1 to 3 for laser cutting a part and collecting elements produced by said cutting, said method comprising the steps of: - the workpiece (4) to be cut is arranged in the axis of the laser beam (2) emitted by the irradiation head (1) of the power laser, - a capture chamber for capturing elements generated by cutting is detachably connected to the laser irradiation head (1), said capture chamber comprising: a) a recess (5) with an exhaust part (7); and b) a blowing nozzle (6) capable of releasing a compressed air flow (8) in the direction of the exhaust part (7) of said recess (5); - said laser projection head (1) emits a laser beam (2) coupled into the exhaust airflow (3); - the blowing nozzle (6) emits a compressed air flow (8) in the direction of the exhaust (7) of the recess (5), so that the elements generated during cutting can be directed in the direction of the exhaust (7).

9. 9. The method according to claim 8, wherein the blowing nozzle (6) emits a compressed air flow (8) having a flow rate between 400 and 2000 liters / minute.

10. 10. A method according to claim 8 or 9 for through-laser cutting of a workpiece, wherein the capture chamber is arranged on a side of the workpiece (4) opposite to the workpiece to be cut to which the laser beam (2) is applied, with a distance of between 10 mm and 100 mm relative to the workpiece to be cut, and the laser beam passes through the workpiece to be cut.

11. 11. The method according to claim 10, wherein the compressed air flow (8) emitted by the blowing nozzle (6) forms an angle comprised between 45 degrees and 90 degrees with respect to an axis formed by the laser beam (2) emitted by the laser irradiation head (1).

12. A method of using an apparatus according to any one of claims 4 to 7 to laser cut a workpiece and collect elements produced by the cutting, the method comprising the steps of: - the workpiece (4) to be cut is arranged in the axis of the laser beam (2) emitted by the irradiation head (1) of the power laser, - a capture chamber for capturing elements generated by cutting is detachably connected to the laser irradiation head (1), said capture chamber comprising: a) a recess (5) with an exhaust part (7); and b) a blowing nozzle (6) capable of releasing a compressed air flow (8) in the direction of the exhaust part (7) of said recess (5); - said laser projection head (1) emits a laser beam (2) coupled into the exhaust airflow (3); - the blowing nozzle (6) emits a compressed air flow (8) in the direction of the exhaust (7) of the recess (5), so that the elements generated during cutting can be directed in the direction of the exhaust (7).

13. 13. The method of claim 12 for non-through laser cutting of a workpiece, wherein the capture chamber is positioned on a side of the workpiece to be cut (4) corresponding to the portion to which the laser beam (2) is applied.

14. 14. The method according to claim 13, wherein the compressed air flow (8) emitted by the blowing nozzle (6) forms an angle comprised between 70 degrees and 135 degrees with respect to an axis formed by the laser beam (2) emitted by the laser irradiation head (1).

15. 15. A method according to any of claims 13 or 14, wherein the vent (7) of the recess (5) forms an angle comprised between 30 and 70 degrees with respect to the piece (4) to be cut.

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