OPTICAL MODULE WITH PULSEED FLASH LAMP

Description

[0001] The present invention relates to the field of high-frequency pulsed light irradiation.

[0002] For information, pulsed light can be used for decontamination in the food, pharmaceutical, cosmetic, medical, aeronautical industries, etc.

[0003] It should be remembered that pulsed light decontamination technology consists of irradiating products, liquids, environments or objects to be decontaminated by emitting pulsed light enriched with UV radiation.

[0004] Document US 4,464,336 describes the general principles of high-frequency pulsed light irradiation technology. This technology uses a lamp comprising a rare gas, preferably xenon, to which a high voltage is applied for a short time window expressed in microseconds or milliseconds. The high voltage applied to the terminals of the lamp causes the gas contained in the lamp to ionize, resulting in the emission of a flash of high light intensity. The light flash corresponds to a radiation or an electromagnetic pulse of white light which has an electromagnetic spectrum ranging from 180 nm to 1100 nm. Conventionally, as described in document US 6,566,659, an irradiation system for a decontamination application. The irradiation system comprises a decontamination chamber which is exposed to the electromagnetic radiation of a pulsed light flash lamp.The flash lamp is mounted in an optical module that optically communicates with the decontamination chamber through a window transparent to electromagnetic radiation between 150 nm and 1200 nm. The optical module also includes a reflector to focus the electromagnetic radiation from the flash lamp onto a target area. The optical module also has UV and debris sensors that ensure the proper functioning of the irradiation system. The UV and debris sensors are powered by a low-voltage electrical circuit integrated into the optical module.

[0005] This document describes a flash lamp that includes a sealed plasma tube containing xenon. The plasma tube extends between two ends, at each end of the plasma tube is arranged an electrode. Each electrode is at least partially in contact with the xenon contained in the plasma tube. The electrodes are configured to transmit a high-voltage electric current through the gas contained in the plasma tube. Ionization of the gas contained in the plasma tube makes the lamp conductive. The high-voltage current that powers the flash lamp can then pass through the lamp and generate a bright flash of high-intensity white light. The electrodes of the lamp are connected to a high-voltage box that is configured to supply a high-voltage electric current at a given frequency.

[0006] According to document US 6,566,659, good decontamination results are obtained when the flashes are operated at a high frequency. However, it is well known that an increase in the flash frequency leads to a significant rise in temperature of the flash lamp and more broadly of the irradiation system.

[0007] In particular, the plasma has a temperature of about 500 to 1000°C depending on the voltage applied to the electrodes. However, it is important that the outer wall of the lamp remains around 100°C.

[0008] In theory, with a flash frequency of 1Hz, ambient air at 20°C is sufficient to cool the lamp. However, increasing the flash frequency leads to a rapid increase in temperature, which can cause solarization problems on the lamp wall and therefore premature aging of the lamp. Breakage of the lamp is also a possibility.

[0009] In this context, it is possible to express the temperature rise of the outer wall of the lamp according to the following formula: Δ T = Rth Φ S

[0010] With, ΔT which corresponds to the temperature difference that exists between the temperature of the outer wall and the interior of the plasma tube; Rth is a coefficient of thermal resistance of the wall of the lamp, Rth is a function of the characteristics of the wall (materials, dimensions); Φ is a coefficient corresponding to the heat flux passing through the wall of the lamp, Φ is a function of the heat emitted by the lamp and the thermal absorption coefficient of the heat transfer fluid; S corresponds to the heat exchange surface, that is to say, to the contact surface of the outer wall of the lamp with the coolant.

[0011] This increase in the temperature of the mechanical and electronic elements that make up the irradiation system can lead to premature wear of these elements.

[0012] Premature wear is a consequence of the extreme conditions to which they are subjected during a high-frequency irradiation process. In this context, it is obvious that regular maintenance operations are necessary to keep a high-frequency pulsed light irradiation system in operation. However, maintenance operations can be delicate due to the complexity of the optical module, which has a low-voltage power supply and a high-voltage power supply.

[0013] In order to maintain the outer wall of the lamp at around 100°C, the outer wall is placed in contact with a cooling fluid when the flash frequency is greater than 1 Hz.

[0014] In the context of an application of pulsed light to skin treatment, document WO 2008 / 012519 describes an optical module which is equipped with a hydraulic cooling circuit for the flash lamp. The cooling circuit has the function of cooling the flash lamp and more generally the elements of the optical unit. This is with the objective of increasing the emission frequency of the flash lamp and thus ensuring optimal treatment.

[0015] In practice, document WO 2008 / 012519 discloses an optical module that includes an open hydraulic cooling circuit. That is, the water is sprayed directly into contact with the flash lamp, which is located in a compartment connected to the hydraulic circuit. However, an open hydraulic cooling circuit can generate sealing problems and risks of electric arcing. This design of the optical module makes maintenance operations even more delicate. Indeed, when dismantling the optical module, water may still be in contact with the flash lamp. This constitutes a major problem given its power supply, which is likely to be high voltage.

[0016] Furthermore, in the context of an industrial application such as decontamination, a pulsed light irradiation system can be equipped with a differentiated cooling system for the flash lamp.

[0017] A differentiated cooling system is a cooling tube independent of the flash lamp. A differentiated cooling system has the disadvantage of requiring perfect centering of the flash lamp within the cooling system. Poor centering of the flash lamp is likely to cause water leakage or even breakage of the flash lamp. Therefore, the use of a differentiated cooling system requires delicate, precise maintenance that can take more than an hour. These maintenance operations are all the more complicated and dangerous for inexperienced personnel. Furthermore, in the context of an industrial process, significant maintenance time is linked to a production shutdown and therefore a slowdown in production.

[0018] Furthermore, these types of systems can be implemented in food production lines, where the use of glass is generally prohibited for certain elements of the production line. This is to prevent broken glass from falling into the food.

[0019] Document WO 2016 / 012488 proposes a solution to improve the design of an optical module and in particular the cooling system of the flash lamp and the reflector. To this end, this document describes a double-envelope flash lamp in which a heat exchanger is integrated which completely surrounds the plasma tube of the lamp. This heat exchanger extends longitudinally between each end of the flash lamp. In addition, at each end of the lamp, a coolant inlet and outlet are provided coaxially with the axis of the lamp. Such a configuration does not allow for the creation of a turbulent flow around the plasma tube. Thus, to optimize the cooling of the plasma tube, it is necessary to increase the pressure of the heat transfer fluid and consequently to use a larger capacity pump.

[0020] Furthermore, document WO 2016 / 012488 describes an optical module that includes a frame with a U-shaped cross-section. Polished aluminum sheets are arranged on the internal walls that form a tunnel to form a reflector. The frame includes a receptacle arranged along a longitudinal axis at the top of the tunnel. The flash lamp is positioned in a receptacle and is subjected to mechanical stresses due to its retention in position in the receptacle. This problem can cause flash lamps to break when installing them or when changing the flash lamp in the receptacle.

[0021] Furthermore, it should be noted that the walls of the aluminum reflector absorb 20% of the heat released by the flash lamp radiation. In fact, the walls of the reflector quickly rise in temperature. At the same time, to ensure proper operation of the flash lamp, it is necessary to maintain the walls of the reflector at a temperature below 100°C. To this end, document WO 2016 / 012488 describes an outer wall of the frame comprising grooves in which run tubes of a heat exchanger cooling the walls of the frame and in particular the walls of the reflector. However, the transfer of heat energy from the reflector to the coolant circulating in the heat exchanger must take place through the aluminum sheet, the wall of the frame and the wall of the tube which constitutes the heat exchanger.To improve thermal conductivity through the walls of the reflector, the frame, and the heat exchanger, a thermally conductive paste is placed between each heat exchanger and the frame. However, this configuration does not allow the reflector temperature to be lowered to temperatures below 150°C. This slows down maintenance operations, since the operator must wait for the temperature to drop before working on the optical module.

[0022] Furthermore, the flash lamp heat exchanger and the reflector heat exchanger are independent and operate in parallel. This mechanical configuration complicates the mechanical structure of the optical module and increases its manufacturing cost.

[0023] This review of the state of the art has allowed us to highlight a problem of accessibility of pulsed light irradiation technology. Although this technology is recognized as effective, particularly for decontamination applications, the complexity of its implementation and maintenance does not allow its development on a larger scale in industrial environments.

[0024] In this context, the present invention provides a technical solution which aims to simplify and secure its design so as, on the one hand, to optimize the operation of a high-frequency irradiation system, and on the other hand, to facilitate maintenance operations of the optical module.

[0025] It is already known from document GB2360946 a pulsed light flash lamp comprising a hermetic plasma tube which contains a pressurized gas and at the ends of which is arranged a plug equipped with an electrode which is at least partially in contact with the gas contained in the plasma tube so as to transmit a high voltage electric current from one end to the other of the flash lamp, thus generating electromagnetic radiation. The plasma tube is entirely integrated in a heat exchanger with a calorific fluid formed by a casing comprising at a first end a colorific fluid inlet orifice and, at its opposite end, an outlet orifice for this calorific fluid, these orifices extending perpendicular to the longitudinal axis of the plasma tube.

[0026] The configuration of the heat fluid inlet and outlet ports allows for the generation of a turbulent heat fluid flow by constraining the fluid inlet and outlet. A turbulent heat fluid flow improves the cooling of the flashlamp during its operation. It is thus possible to increase the frequency of irradiations and / or to maintain a frequency for a longer operating period and to optimize the service life of the flashlamp. Furthermore, the lateral clearance of the heat fluid inlet and outlet ports also contributes to facilitating the insulation of the electrical parts of the flashlamp and to reducing the risk of electric arcing.

[0027] The invention relates more particularly to a pulsed light optical module integrating a flash lamp according to this state of the art and supplied with high voltage current via two electrical connectors.

[0028] An optical module according to the present invention is defined by claim 1. Different embodiments of the invention are defined in dependent claims 2 to 10.

[0029] According to the invention, the optical module has: a support block equipped with a flash lamp receptacle and a window transparent to at least UV rays so as to diffuse the electromagnetic radiation of the flash lamp towards a target area, a reflector block comprising, on the one hand, a reflector which extends along a longitudinal axis, the reflector comprising a groove which extends along the longitudinal axis of the reflector and ensures the reflection and concentration of the electromagnetic radiation of the flash lamp towards a target area, and on the other hand, a cooling system for the optical module.

[0030] In particular, the optical module is characterized in that the reflector and the groove are shaped in the mass, the cooling system of the optical module extending at least partially in the mass of the reflector, said cooling system is also configured so as to connect in a removable manner with the heat exchanger of the flash lamp while the two electrical connectors are isolated from the reflector block and the support block by lateral clearance at the level of the receptacle of the flash lamp.

[0031] On the one hand, the fact that the reflector is formed from the mass simplifies the mechanical design of the optical module. As a result, the manufacturing costs of the optical module are reduced. On the other hand, the integration of the cooling system into the mass of the reflector improves the cooling of the latter. In particular, it is possible to maintain the reflector at a temperature below 100°C during operation. In particular, the reflector can be maintained at a temperature below 45°C. This helps to optimize the operating frequency of the flash lamp but also to facilitate maintenance of the optical module by maintaining acceptable temperatures so that an operator can intervene without delay in the event of a malfunction or breakage of the flash lamp.

[0032] Preferably, the inlet and outlet are extended by a conduit that extends from the heat exchanger in a direction opposite to the plasma tube. Each conduit controls the flow of heat transfer fluid and prevents backflow.

[0033] These improvements help to reduce the danger of pulsed light irradiation systems for manufacturers and make them easier to maintain.

[0034] In this configuration, the input and output ports respectively constitute a quick-connect mechanical connector, similar to a so-called "plug and play" connection. This makes maintenance easier: installing or changing the flash lamp.

[0035] Here, the inlet and outlet ports are configured to connect with a cooling system circulating heat transfer fluid.

[0036] The inlet and outlet ports are each equipped with a spring seal, the two spring seals surrounding an orifice respectively. Each spring seal advantageously fulfills two functions. The first function of the spring seal is to maintain the sealing of the heat exchanger of the flash lamp at the connection with a cooling system. The second function of the spring seal is to provide an elastic mechanical connection with a cooling system. Advantageously, this elastic mechanical connection reduces the mechanical stresses applied to the flash lamp. This effect results in a reduction of flash lamp breakage whether during their installation, their operation or their replacement.

[0037] Advantageously, each cap completely insulates the electrodes from the heat exchanger. In addition, each cap is extended by a sheath that extends outward through the heat exchanger so as to be connected to a high-voltage box. The sheath isolates the high-voltage power supply from the flash lamp. Once again, this feature helps reduce the risk of electric arcing.

[0038] In addition, each sheath has at least one rigid portion that holds the plasma tube in position within the heat exchanger. This makes it possible to maintain the plasma tube in a specific position during operation. This feature makes it possible to reproduce constant electromagnetic radiation towards a target area.

[0039] The heat transfer fluid being formed by a gas and / or water, and preferably deionized water.

[0040] In addition, the removable connection of the optical module cooling system with the flash lamp heat exchanger, and the insulation of the flash lamp electrical connectors, facilitate maintenance operations and reduce the risk of generating an electric arc phenomenon at the optical module and a high voltage power supply box which is an expensive part of the system.

[0041] According to the invention, the reflector block is equipped with gripping means and is removably connected to the support block by manually removable mechanical means. The gripping means help to facilitate the operations of mounting and dismounting the reflector block. Only the reflector block is removable, which reduces the load to be handled, approximately one kilogram, while the entire module has a mass that can reach five kilograms. In addition, no tools are required to carry out maintenance. This facilitates maintenance, which can then be carried out in an area provided for this purpose in a few minutes instead of an hour for a conventional irradiation system.

[0042] According to the invention, the reflector block also comprises a first lateral element and a second lateral element, the two lateral elements are arranged on either side of the reflector, each lateral element is equipped with connection means configured to form a hydraulic connection with the inlet orifice and / or the outlet orifice of the casing of the heat exchanger.

[0043] According to the invention, the support block incorporates electronic sensors which are arranged at the level of the flash lamp receptacle in order to be isolated from the cooling system, their low voltage power supply being laterally clear of the cooling system. This characteristic helps to reduce the risk of an electric arc phenomenon between the cooling system and the power supply of the electronic sensors.

[0044] According to the invention, the cooling system has a first hydraulic connection supplying heat fluid to at least one cooling circuit which is at least partially integrated into the reflector, the cooling system being connected to a heat fluid supply system through its first hydraulic connection and a second hydraulic connection. Preferably, the first hydraulic connection and the second hydraulic connection are arranged opposite the low voltage power supply of the electronic sensors, on the other side of the reflector block. This is to reduce the risk of an electric arc phenomenon.

[0045] According to the invention, the optical module comprises circulation means consisting of a pump and a reservoir, the pump drawing from a reservoir of heat-transfer liquid, the circulation means are remote from the optical module. In addition, deionized water is used as heat-transfer liquid and a deionizing filter is arranged between the reservoir and the pump.

[0046] Other features and advantages will appear in the detailed description which follows, of a non-limiting exemplary embodiment of the invention which is illustrated by the figures 1 to 8 placed in the appendix and in which: There figure 1 is a perspective representation of an optical block of a high-frequency pulsed light decontamination system which is in accordance with one aspect of the invention; The figure 2 is a representation of an exploded view of the optical block of the figure 1, which makes it possible to distinguish a flash lamp conforming to one aspect of the invention; The figure 3 is a perspective representation of the flash lamp visible at the figure 2 ; THE Figures 4 and 5 are representations of the direction of circulation of a heat transfer fluid within the cooling circuit of the optical unit and the flash lamp; The figure 6 is a representation of an exploded view of a complete optical module in accordance with the invention; The figure 7 is a schematic representation of the diffusion and refraction of electromagnetic radiation from the flash lamp towards a target area; and The figure 8 is a schematic representation of a cross-section of a reflector of the optical block.

[0047] As illustrated in figures 1 to 8, one aspect of the invention relates to a pulsed light flash lamp 1 configured to provide, at high frequency, white light electromagnetic radiation which has an electromagnetic spectrum ranging from 180 nm to 1100 nm.

[0048] This document aims to describe the invention in the context of a system for decontaminating a target area 2. However, the invention described in this document can also be applied to all technical or industrial fields which already use pulsed light irradiation technology or are likely to use this technology.

[0049] In this context, the flashlamp 1 comprises a plasma tube 3 which is sealed and contains a pressurized gas. In this example, the gas contained in the plasma tube 3 is maintained at a pressure between 300 Torr and 900 Torr and preferably the pressure is between 450 Torr and 750 Torr.

[0050] In this example, the rare gas xenon is used because of its ability to produce electromagnetic radiation of white light enriched with UV radiation. However, it is also possible to use the rare gas krypton. A xenon / krypton mixture could also be used in various proportions.

[0051] As illustrated in figures 2 , 3 , 5 And 6, the plasma tube 3 extends in a longitudinal direction between a first end 30 and a second end 31. In this example, the plasma tube 3 resembles a rectilinear cylinder. However, the plasma tube 3 could take a multitude of regular or non-regular geometric shapes. For information purposes, the plasma tube 3 may have a length of between 100 mm and 500 mm for an internal diameter of between 0.1 mm and 1 mm. The internal diameter corresponds to the diameter of the enclosure containing the gas which is delimited by the walls of the plasma tube 3.

[0052] At each end 30, 31 of the plasma tube 3 is arranged a plug 32. The plug 32 hermetically ensures that the gas contained in the plasma tube 3 is kept under a determined pressure. In addition, each plug 32 is equipped with an electrode 33 which is at least partially in contact with the gas contained in the plasma tube 3. In contact with the gas, the electrodes 33 make it possible to transmit a high voltage electric current between each end 30, 31 of the flash lamp 1. For the purposes of the invention, a high voltage electric current means that this current has a voltage of between 1500 Volts and 5000 Volts.

[0053] Thus, when a high-voltage current passes through the flash lamp 1, the gas it contains is ionized. In response to this ionization, the gas generates so-called high-intensity electromagnetic radiation. According to the invention, high-intensity electromagnetic radiation means electromagnetic radiation that generates high electrical power of between 0.8 MW and 3 MW.

[0054] In the example illustrated in figures 1 to 6 , each plug 32 is extended by a sheath 34 which extends towards the outside of the flash lamp 1 so as to be connected to a high voltage box capable of powering the flash lamp 1. In order to be connected to a cable of the high voltage box, the sheath 34 is extended outside the flash lamp 1 by an electrical connector 35.

[0055] Of course, each electrical connector 35 is connected to an electrode 33 in order to transmit the high voltage current through the plasma tube 3 of the flash lamp 1. Thus, the electrical connectors 35 define the terminals of the flash lamp 1.

[0056] Remarkably, the flash lamp 1 comprises a heat exchanger 5 with a heat fluid integrated into its structure. In particular, the plasma tube 3 is integral with the heat exchanger 5 with a heat fluid. More specifically, the plasma tube 3 is at least partially integrated into the heat exchanger 5. Thus, the gas contained in the plasma tube 3 can be cooled permanently when using the flash lamp 1. Preferably, the plasma tube 3 is entirely integrated into the heat exchanger 5. Indeed, in this example, the heat exchanger 5 extends in a longitudinal direction around the plasma tube 3 of the flash lamp 1.

[0057] Here, the heat fluid can be formed by a gas and / or water. Air will be preferred as the heat fluid when choosing a gas type heat fluid. While it will be preferable to use deionized water. Indeed, deionized water has the advantage of reducing the risk of an electric arc occurring between the high voltage circuit and the heat fluid circulating in the heat exchanger 5. This characteristic contributes to increasing the safety of the flash lamp 1 during its operation and maintenance.

[0058] Still with this aim of securing the flash lamp 1, the electrodes 33 are completely isolated from the heat exchanger 5. In practice, each sheath 34 protects an electrode 33 by extending, through the heat exchanger 5, towards the outside of the flash lamp 1. In fact, each sheath 34 hermetically connects an electrode 33 to an electrical connector 35 via an electrical cable (not visible). The insulation of the high voltage power supply of the flash lamp 1 from the heat exchanger also makes it possible to reduce the risk of electric arcing.

[0059] In this example, each sheath 34 has at least one rigid portion in order to hold the plasma tube 3 in position within the heat exchanger 5. Here, the plasma tube 3 is held in position along a longitudinal median axis of the heat exchanger 5. The rigid portion of the sheath 34 extends at least from the plug 32 to the outside of the heat exchanger 5. The rigid portion of the sheath 34 corresponds to the portion of the sheath 34 which is internal to the flash lamp 1. It should be noted that sealing means are arranged at the junction between the wall of the heat exchanger 5 and the sheath 34. As an indication, the sealing means may be formed by a conventional seal.

[0060] As illustrated in figures 2 , 3 And 6, the heat exchanger 5 is formed by a casing 50 which extends longitudinally between its two ends 51, 52. At each end 51, 52, the casing 50 has a shoulder 53 which delimits each end 51, 52. Between each shoulder 53 is defined a central part 54 of the casing 50 which contains the plasma tube 3. Thus, each end 51, 52 of the casing 50 contains a part of an electrode 33 and the rigid portion of the sheath 34. In this example, the shoulder 53 also marks a reduction in the diameter of the casing 50 compared to the diameter of the casing 50 in its central part 54.

[0061] In this example, the envelope 50 entirely contains the plasma tube 3 and forms a double skin. The plasma tube 3 and the heat exchanger 5 thus form an inseparable unit. In this sense, it is possible to describe the flash lamp 1 as a double-skin lamp.

[0062] Furthermore, the casing 50 comprises an inlet orifice 55 and an outlet orifice 56 for heat fluid. The inlet orifice 55 and the outlet orifice 56 contribute to generating a circulation of heat fluid around the plasma tube 3. For this purpose, the inlet orifice 55 and the outlet orifice 56 are respectively arranged near one end 51, 52 of the casing 50. The positioning of the inlet orifice 55 and the outlet orifice 56 at each end 51, 52 of the casing 50 contributes to optimizing the circulation of heat fluid.

[0063] In order to generate a sufficiently large flow of heat-transfer fluid, the choice of the internal diameter of the casing 50 depends on the length of the plasma tube 3. For example, according to the invention a sufficient flow rate corresponds to a flow rate of between 4 and 12 liters per minute.

[0064] For information purposes, a sufficient flow rate of heat-transfer fluid can be obtained when the flash lamp 1 is designed according to a ratio of the length of the plasma tube 3 to the internal diameter of the envelope 50 which is between 10 and 20 and preferably this ratio is between 13 and 17.

[0065] In the example illustrated in particular at figure 3 , the inlet orifice 55 and the outlet orifice 56 are extended externally by a conduit which extends from the heat exchanger 5 in a direction opposite to the plasma tube 3. Said conduit extends over a distance of between 15 mm and 20 mm.

[0066] In particular, the inlet orifice 55 and the outlet orifice 56 extend along an axis perpendicular to the longitudinal median axis of the casing 50. In this case, the conduits of the inlet orifice 55 and the outlet orifice 56 are parallel to each other and extend in the same direction.

[0067] In the example of the figure 3 , the inlet orifice 55 and the outlet orifice 56 project from the casing 50 and are laterally clear relative to the longitudinal axis of the plasma tube 3. Each orifice 55, 56 extends at an angle of 90° relative to the longitudinal axis of the plasma tube 3. This configuration makes it possible to constrain the inlet and outlet of heat fluid within the heat exchanger 5. This constraint generates a turbulent flow within the heat exchanger 5. At equal pressure, a turbulent flow makes it possible to improve the heat exchanges between the heat fluid and the plasma tube 3. The cooling of the flash lamp 1 is thereby improved.

[0068] In practice, in order to create a turbulent flow, each orifice 55, 56 can extend at an angle greater than 45° relative to the longitudinal axis of the plasma tube 3. The orifices 55, 56 and their extension constitute mechanical connectors configured to be connected respectively to a conduit of a cooling system of the flash lamp 1.

[0069] Each orifice 55, 56 may have an inner diameter which is less than the diameter of the casing 50. The inner diameter of each orifice 55, 56 may be between 5 mm and 10 mm.

[0070] The reduction in the diameter of each orifice 55, 56 also contributes to generating a turbulent flow of heat-transfer fluid.

[0071] As illustrated in figures 2 , 3 And 6, the inlet orifice 55 and the outlet orifice 56 are respectively equipped with a spring seal 57. In this example, the two spring seals 57 respectively surround the extension of each orifice 55, 56. Each spring seal 57 is a sealing gasket. For this purpose, each spring seal 57 comprises a structure made of elastic material. The elastic material may be made of natural or synthetic rubber, or any other polymer material having elastic properties.

[0072] The structure of each spring joint 57 is equipped with a spring. The spring can be arranged around the periphery of the elastic structure or be integrated into this elastic structure by overmolding.

[0073] It should be noted that the plasma tube 3 and the casing 50 of the heat exchanger 5 are made of a material which has optical properties of transparency over the entire electromagnetic spectrum emitted by the flash lamp 1. For example, it is possible to use fused silica material. Examples of embodiments of a Flash Lamp according to the invention

[0074] As we have previously mentioned, the emission power of a flash lamp 1 according to the invention depends on several parameters.

[0075] As is known, the instantaneous power of a dipole can be calculated using the following formula: P = E Δ t

[0076] With, P = Power in Watts, E = Energy in Joules Δt = Flash duration in seconds

[0077] Classically, energy can be expressed according to the following formula: E = 1 2 CV 2

[0078] With, E = energy in joules C = the lamp capacity in Farads V = The voltage applied across the lamp terminals

[0079] The C and V parameters are identified in the power electronics module. These parameters are determined based on the characteristics of flash lamp 1.

[0080] Two examples of embodiments of the invention are detailed in Table 1 below. Table 1 Settings Example 1 Example 2 Plasma tube length (in mm) 100-200 200-400 Diameter inner tube plasma (in mm) 1-10 1-10 Inner diameter of the envelope (in mm) 10-20 10-20 Capacity (in µF ) 40-60 40-60 Applied voltage (in Volts) 1800-3200 3200-4200 Flash duration (in µs) 80-220 200-220 Flash Power (in Megawatts) 0,9-1,5 1,3-2,5

[0081] As illustrated in figures 1, 2 And 4 has 6 , the flash lamp 1 is configured to operate within an optical module 6. The optical module 6 constitutes a second aspect of the present invention.

[0082] The optical module 6 has at least two blocks: a support block 7 and a reflector block 8 which can be separated from each other.

[0083] As illustrated in the figure 6 , the support block 7 is formed by the covering 60 of the optical module 6. The covering 60 comprises a support plate 61 which preferably extends along a plane. As illustrated in figure 6 , the support plate 61 is delimited by peripheral edges. Here, the peripheral edges are formed by four sides which define a support plate 61 of rectangular shape. However, the support plate 61 could take a multitude of shapes. The cladding 60 also has side walls 62 which extend from the peripheral edges perpendicular to the plane of the support plate 61.

[0084] In the example shown in figure 6, the support block 7 is equipped with a window 70. The window 70 is formed in the support plate 61. The window 70 is delimited laterally by an internal border 63 of the support plate 61. On either side of the window 70 two lateral spaces 64 of the optical module 6 are defined between the internal border 63 and the peripheral edges of the support plate 61.

[0085] Preferably, the window 70 is transparent at least to UV rays so as to diffuse the electromagnetic radiation from the flash lamp 1 towards a target area 2. Preferably, the window 70 is transparent to the entire electromagnetic spectrum emitted by the flash lamp 1. For this purpose, the transparent window 70 can be made of a material which has optical properties similar to the material used for making the plasma tube 3 and the envelope 50.

[0086] The support block 7 also comprises a receptacle 71 for the flash lamp 1. The receptacle 71 and the flash lamp 1 are configured so that the flash lamp 1 is removably positioned in the receptacle 71 by interlocking. This removable nature facilitates the assembly / disassembly of the flash lamp 1 and more generally the maintenance of the flash lamp 1 and the optical module 6.

[0087] Furthermore, the receptacle 71 makes it possible to maintain the flash lamp 1 in position in the axis of the window 70. For these purposes, the receptacle 71 has a first support 72 and a second support 73 which are arranged on either side of the window 70. Each support 71, 72 is secured to the support plate 61 in a lateral space 64 of the optical module 6. Each support 72, 73 is positioned along a median longitudinal axis of the window 70.

[0088] The two supports 72, 73 are in the form of a quadrangular element configured to receive one end 51, 52 of the envelope 50 of the flash lamp 1. Each support 72, 73 comprises a keying device 74, preferably, the keying device 74 consists of a housing provided on its upper face. More precisely, the housing extends longitudinally from one side of the support proximal to the window 70 towards the opposite side of the support, without however joining it. The opposite side of the support is distal to the window 70.

[0089] The keying device 74 is advantageously configured so as to receive an end 51, 52 of the casing 50. In particular, the shape and dimensions of the housing are configured specifically to accommodate an end 51, 52 of the casing 50. In this example, when one end of the casing 51, 52 is fitted into a housing of a keying device 74, the shoulder 53 of this end 51, 52 is arranged in abutment on the side of each support 72, 73 which is proximal to the window 70.

[0090] Each keying device 74 ensures positioning of the flash lamp 1 along the median longitudinal axis of the window 70. For these purposes, the housing extends along the median longitudinal axis of the window 70 so that the flash lamp 1 extends along this same axis. This characteristic makes it possible to optimize the diffusion of the irradiations towards the target zone 2 through the window 70.

[0091] As illustrated in figures 1, 2 And 4, each key 74 has a groove 75 which extends from the housing of the key 74 to the side of each support 72, 73 which is distal of the window 70. The groove 75 is configured to cooperate with the portion of the sheath 34 which extends outside of the flash lamp 1. The groove 75 contributes to the release of the sheath 34 from the support block 7.

[0092] Furthermore, the support block 7 has electronic sensors monitoring the proper functioning of the optical module 6. For information purposes, it is possible to install a UV detector (UV photodiode) on the support block 7 to ensure the quantity of UV radiation received by the target area 2. The support block 7 can also be equipped with a glass break detector which makes it possible to monitor the integrity of the window 70 and / or the flash lamp 1. Advantageously, the electronic sensors are arranged at one of the two supports 72, 73. In this example, the electronic sensors are arranged at the support 73. The support plate 61 has holes so that the electronic sensors are pointed towards the target area 2. The electronic sensors are powered by a low-voltage power supply 76. The low-voltage power supply 76 can be formed by a conventional twelve-volt electronic power supply.In this example, the low voltage power supply 76 is laterally released from the optical module 6.

[0093] For information purposes, the two supports 72, 73 may be designed in a polymeric and / or composite material. For information purposes, it is possible to use fluoropolymers such as polyvinylidene fluoride (PVDF) or polytetrafluoroethylene (PTFE). Advantageously, a fluorinated polymeric material is resistant to electromagnetic radiation from UV light. Such a choice makes it possible to increase the longevity of the support block 7.

[0094] As illustrated in the figure 6 , the support block 7 is configured to cooperate with the reflector block 8. In particular, the reflector block 8 fits specifically with the support block 7 from above the latter.

[0095] Let us consider the composition of the reflector block 8. The reflector block 8 comprises a reflector 80. In this example, the reflector 80 is formed from a single piece. This means that it is formed from a single piece of a given block of material. Preferably, the material is chosen to be metallic.

[0096] As illustrated in the figure 7, the reflector 80 provides a first function of reflection and concentration of the electromagnetic radiation from the flash lamp 1 in the direction of the target zone 2. For this purpose, the reflector 80 is a quadrangular part which has an upper face 800 and two lateral faces 801 which extend longitudinally on either side of the upper face 800. The upper face 800 and the lateral faces 801 form a cover configured to cover the window 70. Furthermore, the reflector 80 has a groove 81 which extends longitudinally in the quadrangular part. Here, the groove 81 is formed in the mass of the quadrangular part.

[0097] As illustrated in the figure 8, the groove 81 passes longitudinally through the quadrangular part so as to form a tunnel. In addition, the groove 81 is preferably polished so as to have optical reflection properties. Thus, the groove 81 ensures the reflection and concentration of the electromagnetic radiation from the flash lamp 1 towards the target area 2.

[0098] For information purposes, the reflector 80 may be made of a metallic material such as steel and preferably aluminum. The purpose of the reflector 80 is to reflect the electromagnetic radiation emitted by the flash lamp 1 and in particular the UV portion of this radiation. In this sense, the polished aluminum reflects 80% of the UV electromagnetic radiation emitted by the flash lamp 1.

[0099] The reflector 80 has dimensions slightly larger than those of the window 70 so as to rest on the support plate 61 between the internal border 63 and the peripheral edges. Thus, the reflector 80 is shaped so as to cover, on the one hand, the flash lamp 1 positioned in its receptacle 71, and on the other hand, the window 70 formed in the support plate 61.

[0100] As illustrated in figures 1, 2 , 4 And 6 , the reflector block 8 also comprises a first lateral element 82 and a second lateral element 83. The two lateral elements 82, 83 are secured to the optical reflector 80. More precisely, the two lateral elements 82, 83 are secured to the optical reflector 80 on either side of the groove 81 at each of its ends 810, 811. Thus, an upper face of each lateral element 82, 83 laterally extends the upper face 800 of the reflector 80.

[0101] Each lateral element 82, 83 is configured to cooperate with a determined support 72, 73 of the receptacle 71 of the flash lamp 1. Indeed, each lateral element 82, 83 comprises a housing complementary to the housing of the keying device 74 of each support 72, 73. The complementary housing ensures that a lateral element 82, 83 fits into a support 72, 73 while maintaining the flash lamp 1 in position within the optical unit 6.

[0102] In the same way, each lateral element 82, 83 comprises a groove 84 complementary to the clearance groove 75 of each support 72, 73. The grooves 75, 84 respectively arranged on a support 72, 73 and on a lateral element 82, 83, jointly contribute to laterally clearing the outer portions of the sheaths 34 of the support block 7 and of the reflector block 8. Consequently, the flash lamp 1 comprises two electrical connectors 35 which are isolated from the reflector block 8 and from the support block 7 by lateral clearance at the level of the receptacle 71 of the flash lamp 1 (illustrated in figure 1 And 4 ). The electrical connectors 35 are connected by cables to a high-voltage box independent of the optical module 6.

[0103] For information purposes, each lateral element 82, 83 may be made of a polymeric and / or composite material. As for the supports 72, 73 of the support block 7, and for the same reasons, it is preferable to use a polymeric / composite material resistant to UV radiation.

[0104] Advantageously, the reflector block 8 is removably connected to the support block 7. For this purpose, the optical module 6 comprises mechanical means 9 that can be manually dismantled. For example, these mechanical means 9 can be formed by captive screws. This feature allows an operator to carry out a maintenance operation without using a tool.

[0105] The mechanical means 9 cooperate with a first bore 90 made at a determined position in each lateral element 82, 83. The mechanical means 9 also cooperate with a second bore 91 which is made at a determined position in each of the supports 72, 73. The position of the second bore 91 corresponds to the position of the first bore 90 so that they are positioned along a common axis when the reflector block 8 is fitted with the support block 7.

[0106] In the example illustrated in figures 1, 2 , 4, 5 And 6, the optical module 6 is advantageously equipped with gripping means 65. Here, the gripping means 65 are integral with the reflector block 8 at the upper face 800 of the reflector 80. In this example, the gripping means 65 are formed by a handle. The gripping means 65 allow an operator to easily separate the reflector block 8 from the support block 7 in order to carry out maintenance operations. Obviously, the assembly of the reflector block 8 on the support block 7 is also facilitated and accelerated during the mounting or remounting of the optical block 6.

[0107] Further as illustrated in figures 1, 2 , 4, 5 And 8 , the reflector block 8 comprises a system for cooling the optical module 6. The cooling system comprises at least one cooling circuit 10 with heat-transfer fluid. Preferably, the cooling circuit 10 is at least partially integrated into the reflector 80.

[0108] The cooling circuit 10 is supplied with heat fluid by a hydraulic connection 11, 16. In this example, the hydraulic connection 11, 16 is arranged on the first lateral element 82 of the reflector block 8.

[0109] According to a first variant of the invention illustrated in Figures 4 and 5 , the heat fluid inlet is connected to a first hydraulic connection 11. This configuration makes it possible to transmit the heat fluid directly to the heat exchanger 5 of the flash lamp 1. It is only in a second step that the heat fluid enters the cooling circuit 10.

[0110] According to a second variant of the invention, the heat fluid inlet is connected to a second hydraulic connection 16. This configuration makes it possible to transmit the heat fluid directly into the cooling circuit 10. According to this variant, the reflector 80 is cooled by a colder heat fluid. Such a configuration makes it possible to better cool the reflector 80 when the flash frequency is greater than or equal to 1 Hz.

[0111] For these purposes, each lateral element 82, 83 is equipped with connection means 12, 13 to the inlet orifice 55 and / or to the outlet orifice 56 of the casing 50 of the heat exchanger 5. During the fitting between the support block 7, the flash lamp 1 and the reflector block 8, the connection means 12, 13 are configured so as to engage with the inlet orifice 55 and / or to the outlet orifice 56 which are held in position by the keying member 74.

[0112] Advantageously, when the support block 7, the flash lamp 1 and the reflector block 8 are fitted together, the first hydraulic connection 11 is connected to the inlet orifice 55 of the heat exchanger 5 through the connection means 12 of the first lateral element 82. In parallel, the outlet orifice 56 is connected to the connection means 13 of the second lateral element 83. In this example, the connection means 13 are connected to the cooling circuit 10 of the reflector 80 via an external conduit 14. Here, the external conduit 14 connects to the part of the cooling circuit which is integrated into the reflector 80. The connection between the external conduit 14 and the part of the cooling circuit 10 which is integrated into the reflector 80 is positioned at the first lateral element 82.

[0113] The connection means 12, 13 may respectively be constituted by a socket. The socket has an internal diameter greater than the diameter of each orifice 55, 56. Each orifice 55, 56 thus constitutes a male mechanical connector configured to form a mechanical connection with the connection means 12, 13 which are of the female type.

[0114] According to the invention, the respective connections between the connection means 12, 13 and the orifices 55, 56 are made by fitting the orifices 55, 56 into the connection means 12, 13. Said connections constitute the only mechanical links between the flash lamp 1 and the reflector block 8.

[0115] In this context, each spring seal 57 is inserted inside a socket of a connection means 12, 13. This has the effect of reducing the mechanical stresses which apply to the fixings of the flash lamp 1. The spring seal 57 advantageously makes it possible to limit breakages of the flash lamp 1 during their installation or replacement. Furthermore, during use, the spring seal 57 makes it possible to place the flash lamp 1 in suspension by creating an elastic mechanical connection.

[0116] In addition, the spring of the spring seal 57 produces, before the arrival of the heat fluid, a prestress inside the sleeve which ensures the sealing of the connection in the absence of heat fluid or when the heat fluid arrives. The elasticity of the seal 57 also allows it to compress when the pressure of the heat fluid increases, thus ensuring perfect sealing of the hydraulic connection. This characteristic contributes to increasing the safety of the optical module 6.

[0117] As illustrated in the figure 8, the cooling circuit 10 is partially integrated into the mass of the reflector 80. In particular, the cooling circuit 10 comprises a heat exchanger 15. Here, the heat exchanger 15 runs longitudinally along the reflector 80. In practice, the heat exchanger 15 makes at least one back and forth movement on either side of the groove 81. At the outlet of the part of the cooling circuit 10 which is integrated into the reflector 80 there is a second hydraulic connection 16 for the heat transfer fluid. Advantageously, the second hydraulic connection 16 is arranged at the level of the first lateral element 82.

[0118] It should be noted that the first hydraulic connection 11 and the second hydraulic connection 16 are respectively connected to a heat fluid supply system. According to the variant of the invention, the connection of the heat fluid inlet and outlet can be reversed on the first hydraulic connection 11 and the second hydraulic connection 16. The direction of circulation of the heat fluid is then reversed.

[0119] Furthermore, to avoid the presence of ions despite a passage through the metallic mass of the reflector 80, the conduit of the heat exchanger 15 can be oxidized beforehand. When the reflector 80 is made of aluminum (AI), the oxidation of the conduit of the heat exchanger 15 leads to a conduit made of aluminum oxide (Al2O3) or commonly called alumina which has insulating properties. The small thickness of alumina (a few µm) will not cause any cooling problems. In addition, the alumina has a thermal conductivity of 10.9 Wm-1.K-1 which allows the cooling of the reflector 80 to be ensured.

[0120] The heat fluid supply system may comprise means for circulating the heat fluid and a heat fluid reservoir. In this example, the heat fluid supply system is external to the optical module 6. This is to reduce the risk of electric arcing.

[0121] In the case of a gas-type heat fluid, the circulation means can be formed by a pump connected to a gas tank or having an ambient air intake.

[0122] In the case of a heat transfer fluid of the heat transfer liquid type, the circulation means may consist of a pump drawing from a heat transfer fluid reservoir. When deionized water is used as the heat transfer fluid, a deionizing filter is advantageously placed between the reservoir and the pump. The deionizing filter makes it possible to eliminate any ions that may have been captured by the heat transfer fluid during its travel.

[0123] Furthermore, the specific arrangement of the cooling system has several advantages. Generally, this cooling system is configured to connect removably with the heat exchanger 5 of the flash lamp 1. This feature makes it possible to simplify the maintenance operations of the optical module 6.

[0124] According to the variant of the invention illustrated in Figures 4 and 5 , due to the configuration of the cooling system, the heat fluid first passes through the heat exchanger 5 of the flash lamp 1. This prevents a heat fluid from becoming charged with ions by passing through the mass of the metallic reflector 80 before coming into contact with the plasma tube 3. This helps to reduce the risk of an electric arc phenomenon occurring in the cooling system.

[0125] At the outlet of the heat exchanger 5 of the flash lamp 1, the heat fluid passes through the external conduit 14 in order to enter the heat exchanger 15 of the reflector 80 at the level of the first lateral element 82. At the outlet of the heat exchanger 15 of the reflector 80, the heat fluid joins the heat fluid supply system via the second hydraulic connection 16. It should be noted that the circulation of the heat fluid within the cooling system and the heat exchanger 5 is shown diagrammatically on the Figures 4 and 5 by arrows that follow one another.

[0126] For this same purpose, the first hydraulic connection 11 and the second hydraulic connection 16 of the cooling circuit 10 are both arranged on the same side of the reflector 80. Indeed, the first hydraulic connection 11 and the second hydraulic connection 16 are arranged at the level of the first lateral element 82. This characteristic also helps to reduce the risk of an electric arc phenomenon occurring at the periphery of the optical module 6. The heat fluid supply is therefore perfectly isolated from the high voltage supply of the flash lamp 1. In addition, the low voltage supply 76 of the optical module 6 is integrated on the other side of the reflector 80, in the second support 73 of the receptacle 71.

[0127] Thus, the heat fluid supply is carried out on one side of the reflector 80 while the low voltage supply of the electronic part of the optical module 6 is carried out on the other side of the reflector 80. In addition, as we mentioned previously, the high voltage electrical connectors 35 of the flash lamp 1 are insulated and laterally released from the optical module 6. All these characteristics and their arrangement contribute to reducing the generation of an electric arc during operation of the optical module 6 or during a maintenance operation.

[0128] It should be noted that a cover may be provided in order to cooperate with the side walls 62 in order to close the upper part of the covering 60 of the optical module 6.

Claims

1. Pulsed light optical module (6) incorporating a pulsed light flashlight (1) comprising a sealed plasma tube (3) which contains a pressurized gas, the plasma tube (3) extending along a longitudinal axis between a first end (30) and a second end (31), a plug (32) being arranged at each end (30, 31) of the plasma tube (3), which plug is equipped with an electrode (33) which is at least partially in contact with the gas contained in the plasma tube (3) so as to transmit a high-voltage electric current from one end to the other of the flashlight (1), thereby generating electromagnetic radiation, the plasma tube (3) being fully incorporated into a heat exchanger (5) with heat-transfer fluid, the heat exchanger (5) being formed by a shell (50) extending between two ends (51, 52) and comprising an inlet port (55) and an outlet port (56) for heat-transfer fluid, the inlet port (55) and the outlet port (56) being respectively arranged at one end (51, 52) of the shell (50), the inlet port (55) and the outlet port (56) protruding from the shell (50), being laterally open with respect to the longitudinal axis of the plasma tube (3) and extending at an angle greater than 45° with respect to the longitudinal axis of the plasma tube (3), the electrodes (33) opening outward through the heat exchanger (5), through a sheath (34) which extends along the longitudinal axis of the plasma tube (3), each plug (32) completely insulating the electrodes (33) from the heat exchanger (5), the flashlight (1) being supplied with high-voltage current via two electrical connectors (35), said optical module (6) having: - a support block (7) equipped with a receptacle (71) for the flashlight (1) and a window (70) which is transparent to at least UV rays so as to diffuse the electromagnetic radiation from the flashlight (1) toward a target area (2), - a reflector block (8) comprising, on the one hand, a reflector (80) which extends along a longitudinal axis, the reflector (80) comprising a groove (81) which extends along the longitudinal axis of the reflector (80) and ensures the reflection and concentration of the electromagnetic radiation from the flashlight (1) in the direction of a target area (2), and on the other hand, a system for cooling the optical module (6), the reflector (80) and the groove (81) being shaped in the mass, the cooling system of the optical module (6) extending at least partially into the mass of the reflector (80), said cooling system also being configured to connect removably to the heat exchanger (5) of the flashlight (1), while the two electrical connectors (35) are insulated from the reflector block (8) and the support block (7) by lateral clearance at the receptacle (71) of the flashlight (1).

2. Pulsed light optical module (6) claim 1, characterized in that the inlet port (55) and the outlet port (56) are each equipped with a spring seal (57), the two spring seals (57) each encircling a port (55, 56).

3. Pulsed light optical module (6) according to one of claims 1 and 2, characterized in that each sheath (34) has at least one rigid portion holding the plasma tube (3) in position within the heat exchanger (5).

4. Pulsed light optical module (6) according to one of claims 1 to 3, characterized in that the heat-transfer fluid is formed by a gas and / or water, preferably deionized water.

5. Pulsed light optical module (6) according to any of the preceding claims, characterized in that the reflector block (8) is equipped with gripping means (65) and is removably connected to the support block (7) by manually removable mechanical means (9).

6. Pulsed light optical module (6) according to any of the preceding claims, characterized in that the reflector block (8) also comprises a first side member (82) and a second side member (83), the two side members (82, 83) being arranged on either side of the reflector (80), each side member (82, 83) being equipped with connection means (12, 13) configured to form a hydraulic connection to the inlet port (55) and / or to the outlet port (56) of the shell (50) of the heat exchanger (5).

7. Pulsed light optical module (6) according to any of the preceding claims, characterized in that the support block (7) carries electronic sensors which are arranged level with the receptacle (71) of the flashlight (1) in order to be insulated from the cooling system, the low-voltage supply (76) thereof being laterally open with respect to the cooling system.

8. Pulsed light optical module (6) according to any of the preceding claims, characterized in that the cooling system has a first hydraulic connection (11) supplying heat-transfer liquid to at least one cooling circuit (10) which is at least partially incorporated into the reflector (80), the cooling system being connected to a heat-transfer fluid supply system via its first hydraulic connection (11) and a second hydraulic connection (16).

9. Pulsed light optical module (6) according to any of the preceding claims, characterized in that it comprises circulation means consisting of a pump and a reservoir, the pump drawing from a reservoir with heat-transfer liquid, the circulation means being remote from the optical module (6).

10. Pulsed light optical module (6) according to claim 9, deionized water being used as the heat-transfer liquid and a deionizing filter being arranged between the reservoir and the pump.