EP1869695A2

EP1869695A2 - Microwave device for treating a flux with visible radiation

Info

Publication number: EP1869695A2
Application number: EP06743230A
Authority: EP
Inventors: Pascal Sortais; Xavier Pellet
Original assignee: RC-LUX; RC LUX
Current assignee: RC-LUX; RC LUX
Priority date: 2005-04-01
Filing date: 2006-03-31
Publication date: 2007-12-26
Also published as: FR2884043A1; WO2006103287A3; WO2006103287A2; BRPI0609775A2

Abstract

The invention relates to a device for treating a flux with visible radiation. The inventive device comprises: microwave generation means (10a, 10b, 10c); at least one microwave cavity (20) comprising microwave-tight walls for confining the microwaves; at least one irradiation channel (30) through which the flux to be treated travels; at least one chamber (40) containing a plasma, which is disposed inside the microwave cavity; and means for generating a magnetic field (50). According to the invention, the chamber(s), the cavity or cavities and the magnetic field and microwave generation means are arranged such as to generate an electron cyclotron resonance inside the chamber(s) in order to emit visible radiation, thereby enabling the irradiation of the fluid to be treated. The invention is characterised in that the magnetic field generation means comprise at least one permanent magnet and in that each chamber is disposed in close proximity to at lest one magnet.

Description

MICROWAVE DEVICE FOR PROCESSING A FLOW BY LIGHT EMITTING

The invention relates to the general technical field of the treatment of a flux by light irradiation.

More particularly, the invention relates to the technical field of treating a gas, a liquid, or a solid by means of infrared, visible or ultraviolet light radiation emitted by a device excited by microwave and generating Cyclotron Electron Resonance (ECR).

The invention is advantageously but not limited to application in the field of sterilization of water and air.

GENERAL PRESENTATION OF THE PRIOR ART

Devices have already been proposed for treating a flux by light irradiation.

Among these devices, there are known devices comprising one or more lamps low or medium pressure mercury, supplied with high voltage, positioned inside a tank for the circulation of a flow.

However, these devices have many drawbacks in particular in terms of space, life, difficulty of ignition and non-adjustable power of medium and low pressure lamps.

To overcome the disadvantages of these devices, devices have been proposed excited by microwaves.

These devices include:

a cavity for the confinement of microwaves and allowing entry and exit of the flow,

microwave generation means comprising a microwave generator and means for bringing the microwaves of the generator to the cavity,

an irradiation channel in which the flux to be irradiated circulates, at least one chamber, positioned inside the cavity, containing a plasma intended to be excited by the microwaves so as to emit light radiation.

These devices have specific geometries and arrangements depending on the substance to be irradiated and the desired irradiation mode.

The patents WO9837962 and WO9953524 define a rectangular microwave cavity, a tubular irradiation channel, an annular chamber positioned inside the microwave cavity around the irradiation channel of a gas or liquid flow. Patents JP611046290 and JP61198545 define a rectangular cavity, an irradiation channel merged with the microwave cavity and serving as a water reservoir. The plasma chamber is inside the microwave cavity, immersed in the water to be treated.

Patents FR2674526 and US3911318 describe a tubular microwave cavity, a tubular irradiation channel and an annular chamber positioned inside the microwave cavity, around the irradiation channel of an optical fiber or a fluid.

US5931557 patent defines a rectangular cavity and several geometries of irradiation channels associated with plasma enclosures for irradiating an air flow.

The patent US6559460, designed in a more complex microwave cavity geometry, adds light reflection means to improve the uniformity of the irradiation of a substrate flux.

However, these devices induce operating constraints on:

the dimensions and the shape of the microwave cavity (see WO9837962, JP611046290, JP61198545, US3911318, US5931557),

the minimum microwave power to be supplied (see WO9837962, JP61198545, FR2674526, US5931557, US6559460),

positioning the plasma chamber (s) inside the microwave cavity (see US Pat. These multiple conditions taught to one skilled in the art to implement a device excited by microwaves for the treatment of a flow do not allow it to provide a compact device.

In addition, the constraints imposed in these documents on the size and shape of the microwave cavity, and on the positioning of the speakers inside the cavity prevent optimizing the irradiation of the flow. In addition, these devices have limited effectiveness and brightness.

In the context of the present invention, the term "brightness" refers to the radiation density per unit area. In the context of the present invention, the term

"Efficiency", a yield corresponding to the ratio of the light energy generated by the device to the microwave power supplied to the device.

Finally, these devices work very poorly at low power (less than 200 Watts).

To overcome the low-gloss disadvantages of the aforementioned devices excited by microwaves, devices using the phenomenon of ECR have been proposed.

NCE is known to improve the energy level of microwave excited plasmas.

It consists in introducing a magnetic field which, as a function of the frequency of the microwave wave and the value of the magnetic field, causes a cyclotron resonance inside the chamber of a plasma with very low pressure. plasma electrons. This phenomenon improves the brightness of the radiation of the enclosure.

US 3,911,318 discloses a microwave device for processing a material flow by light irradiation.

The device comprises Helmholtz coils for generating a magnetic field to obtain an ECR inside an annular plasma enclosure enveloping a tubular irradiation circuit.

This device improves the brightness of the speaker but has the following disadvantages:

this device is bulky because of the use of Helmholtz coils, this device is not very compact because the microwave cavity is of a volume that is multiple of the wavelength (useless volume between the microwave cavity and the plasma enclosure) in order to obtain zones of maximum electromagnetic field; this device does not protect the irradiation channel of microwaves, which is particularly penalizing in the case of the treatment of a liquid,

this device does not have all the necessary safety conditions for the treatment of a flow and more particularly of a liquid: in particular, the device exhibits microwave leaks at the inlet and outlet of the flow; to treat, o the use of the device described in US 3,911,318 is dangerous if the flow to be irradiated is water because the use of Helmholtz coils requires the application of large currents to allow the generation of a field magnetic field sufficiently powerful that a Cyclotron Electron Resonance is obtained.

An object of the invention is to propose a microwave treatment device for the flow (liquid, gas or solid) having all the necessary security and which combines compactness, brightness and efficiency, low power operation and which optionally allows protect the fluid from microwaves if necessary.

PRESENTATION OF THE INVENTION

For this purpose, a device for the treatment of a flux by a light radiation is provided, the device comprising:

means for generating microwaves; at least one microwave cavity comprising microwave-tight walls for confining the microwaves;

at least one irradiation channel in which the flow to be treated circulates,

at least one chamber containing a plasma, located inside the microwave cavity, means for generating a magnetic field, enclosure (s), cavity (s), and means for generating the magnetic field and microwaves being arranged so as to generate a cyclotron resonance of electrons inside the (s) the enclosure (s) for emitting light radiation for irradiating the fluid to be treated, wherein the magnetic field generating means are constituted by at least one permanent magnet and each enclosure is disposed in the immediate vicinity of at least one magnet.

In the context of the present invention, the term "flux" is intended to mean a gas, a liquid or a moving solid, that is to say more particularly that circulate in the channel.

In the context of the present invention, the term "immediate proximity" is understood to mean a distance D between the enclosure and the permanent magnet less than or equal to a dimension L of the magnet along an axis (parallel to the vector d magnetization of the magnet) favored magnetization of the magnet, preferably less than or equal to L / 2.

Preferred but non-limiting aspects of the device according to the invention are the following:

each cavity is part of a volume, at least one of the characteristic dimensions (height, length, width) of the smallest volume in which the microwave cavity is inscribed being less than 25 centimeters,

the device comprises means for controlling the microwave power, and / or the gas pressure and / or the temperature of the device, at a desired light intensity,

the device comprises means for modulating the power of the microwaves in the enclosure, these means for modulating the power generating pulses,

each cavity is associated with a single antenna. In one embodiment, the permanent magnet (s) is (are) disposed inside the microwave cavity (s).

According to a first variant of this embodiment, the (or) channel (s) is (are) disposed (s) inside the (or) cavity (s). Optionally, the walls forming the (or) cavity (s) and the walls forming the (or) channel (s) may be merged, and the device may comprise a plurality of enclosures and a plurality of permanent magnets.

According to a second variant of this embodiment, the device comprises one or more cavities arranged to encompass the channel (s), the walls of the cavity (s) ( s) facing the (or) channel (s) being transparent to the light radiation. Furthermore, the (or) channel (s) is (or are) tubular, and the (or) cavity (s) is (or are) ring-shaped.

The second variant of the embodiment can: - either comprise a single ring-shaped enclosure,

- Or include a plurality of speakers around the channel. Optionally, in the device according to the invention, either:

each enclosure is associated with a permanent magnet of its own, ie each magnet is associated with a plurality of speakers, or

each enclosure is associated with a plurality of permanent magnets.

In all cases, the device may comprise means for reflecting the light radiation arranged so as to direct the light radiation towards the flow to be treated.

Furthermore, in all cases, the (or) outer wall (s) of the (or) cavity may (wind) be opaque (s) to light radiation.

In addition, in all cases, the means for generating microwaves comprise either: a microwave energy generator and a waveguide, the waveguide being disposed between the generator and the cavity to guide the microphones; - waves generated by the generator to the cavity,

a microwave energy generator, at least one coaxial cable, and at least one antenna, the cable (s) being (are) arranged between the generator and the cavity, the antenna (s) ( s) being disposed within the cavity (s).

The invention also relates to a method for treating a flux by light radiation by using a device according to one of the two preceding claims, the light radiation having a predetermined light spectrum and intensity, characterized in that the method comprises a step of controlling the spectrum as a function of the average time power of the microwaves in the enclosure and the maximum power of the microwaves in the pregnant.

PRESENTATION OF FIGURES

Other features, objects and advantages of the present invention will become apparent from the description which follows, which is purely illustrative and nonlimiting and should be read with reference to the accompanying drawings in which:

FIGS. 1, 2, 6, 7, 9 and 11 are longitudinal sectional views of various embodiments of the device according to the invention, FIGS. 3, 4, 5, 8, 10 and 12 are views. in cross section of different embodiments of the device according to the invention,

FIG. 13 schematically illustrates a particular embodiment of an assembly comprising four devices according to the invention, FIG. 14 represents, as a function of time, three particular embodiments of the microwave energy supplying the device according to the invention. the invention.

DESCRIPTION OF THE INVENTION

The device for the treatment of a flux by a light radiation according to the invention will now be described with reference to FIGS. 1 to 14.

With reference to FIG. 1, the device according to the invention comprises: microwave generation means 10a, 10b, 10c,

at least one microwave cavity for confining the microwaves,

at least one irradiation channel in which the flow to be treated circulates, at least one enclosure 40 containing a plasma, situated inside the microwave cavity, and

means for generating a magnetic field 50.

The means for generating microwaves 10a, 10b, 10c comprise a microwave energy generator 10a and means for bringing the microwaves 10b, 10c into the cavity 20.

The microwave energy generator 10a and the means for guiding the microwaves 10b, 10c in the cavity 20 may be any means known to those skilled in the art to perform these functions. The microwave energy generator 10a is for example of the electron tube type, transistor, or magnetron.

The means for bringing the microwaves 10b, 10c into the cavity 20 are, for example:

a waveguide (s), a coaxial cable (s) 10b and an antenna (s) 10c.

In the context of the present invention, the term "microwaves" is intended to mean electromagnetic waves of frequencies greater than 1 GHz, preferably less than 30 GHz, more preferably between 1.8 GHz and 6.4 GHz.

The microwave energy generators of standard microwave ovens allow the generation of magnetic waves with a frequency of 2.45 GHz. Since these microwave energy generators are widespread, microwave energy generators can advantageously be used for generating magnetic waves of frequency equal to 2.45 GHz.

Microwave cavity 20 is a Faraday cage. The microwave cavity 20 is intended to confine the microwaves within it to protect the external environment against the electromagnetic fields produced inside the cavity 20. For this purpose, the cavity 20 comprises walls that are opaque to the microphones. -ondes. The cavity may comprise walls that are transparent to light, and more particularly the walls of the cavity directly facing the channel in which the flow to be treated circulates. The walls transparent to light, and opaque to microwaves may be electrically screened conductor 23 or 24. The microwave cavity 20 is of any shape and size. More particularly, the shape and dimensions of the cavity 20 are independent of the frequency of the microwaves. The irradiation channel 30 is a volume of any shape and size and variable along the channel 30. The channel 30 includes a stream inlet 30a and a stream outlet 30b. The irradiation channel 30 allows the circulation of the flux to be irradiated, the direction of circulation of the flow being given by the arrow referenced SCF in the accompanying drawings. The irradiation channel is made of a material that is transparent to light radiation, preferably made of quartz or glass. In some embodiments, the channel is a removable tube. Thus, in the case of a water flow, instead of descaling a channel integral with the device, the tube can simply be replaced by a clean tube. Descaling can also be done with a brush.

The chamber 40 containing the plasma is a sealed enclosure for the confinement of any gas at low pressure. This enclosure 40 is of any shape and size. The walls of the chamber 40 are transparent to microwaves. The enclosure 40 comprises at least one wall transparent to the light radiation emitted by the plasma. This transparent wall is the wall facing the channel in which the flow to be treated flows. The other wall of the enclosure may optionally be opaque to light radiation, and preferably include a reflective coating for reflecting light radiation to the channel.

In the context of the present invention, the term "low pressure" means a pressure of between 10 ^-4 and 10 millibar.

The means for generating a magnetic field 50 are means for generating a magnetic field. The enclosure 40 (or the enclosures), the cavity (s) 20, and the means 10a, 10b, 10c, 50 for generating the magnetic field and the microwaves are arranged in such a way as to generate a Cyclotron Resonance Electron (hereinafter referred to as ECR) inside the enclosure (or enclosures) to emit light radiation for irradiation of the fluid to be treated. RCE, or Gyromagnetic Resonance, is a technique for activating a plasma. The principle of plasma activation consists in superimposing on an electromagnetic wave of a given frequency a static magnetic field such that the frequency of gyration of the electrons in the magnetic field is equal to the frequency of the electromagnetic excitatory wave.

When the phenomenon of resonance occurs, the electrons of the plasma gain energy and, by collision, ionize the plasma: a light radiation is then generated. The phenomenon of RCE improves the brightness and effectiveness of the radiation of the enclosure.

A first feature of the device according to the invention relates to the fact that the generation means of the magnetic field 50 are constituted by at least one permanent magnet. This permanent magnet 50 is of any shape. The dimensions of the permanent magnet 50 are chosen as small as possible in order to obtain the ECR in the enclosure. The person skilled in the art knows how to determine the minimum dimensions of the magnet making it possible to obtain an ECR in the enclosure. Whatever the shape of the permanent magnet 50, it has a preferred axis of magnetization parallel to the magnetization vector of the magnet.

The permanent magnet 50 may be constituted by a single magnet or by a plurality of elementary permanent magnets contiguous. A second feature of the device according to the invention relates to the fact that the means for generating the magnetic field 50 are arranged near at least one enclosure 40.

In the context of the present invention, the term "immediate proximity" means a distance D between the enclosure 40 and the permanent magnet 50 less than or equal to the dimension L of the magnet 50 along the axis of the magnet. preferred magnetization of magnet 50, preferably less than or equal to L / 2.

Even more preferably, the permanent magnet 50 is in contact with the wall of the enclosure 40 - in other words the distance D between the enclosure 40 and the magnet 50 is zero - possibly with a reflector wall 60 or cavity 20 between permanent magnet 50 and enclosure 40.

The fact that the means for generating the magnetic field 50 consist of one or more magnets 50 disposed in the immediate vicinity of one or more enclosures 40 allows:

to improve the brightness and effectiveness of the radiation of the enclosures 40,

- to design devices with cavities 20 completely sealed to microwaves, of any size not necessarily multiple of the wavelength of microwaves and compact form, which may optionally protect the irradiation channel of microwaves ,

- to access operations with immediate ignition at very low power (a few watts) when the cavity has a dimension greater than ¹ A of the wavelength,

to create zones 80 of brightness by RCE which can be positioned, freely and precisely, in order to optimize the effectiveness of the irradiation with respect to the flow to be treated.

The description of the elements of the device according to the invention made above with reference to FIG. 1 also applies to the other embodiments illustrated in FIGS. 2 to 14.

In the embodiment illustrated in FIG. 1, the enclosure 40 is of annular shape and comprises, for example, a mercury plasma for emitting a radiation with a wavelength of 254 nm which is bactericidal.

The chamber 40 is disposed around the irradiation channel 30 which has a tubular shape.

The chamber 40 is disposed inside the microwave cavity 20 which is also annular in shape and includes the irradiation channel 30. An application of the embodiment illustrated in FIG. 1 can be the treatment of small flows. of water by a light radiation of wavelength equal to 254nm.

This device makes it possible to emit light radiation on a flow of water of a few m3 / h passing on a standard pipe (3/4 of an inch). The channel 30 is preferably tubular and transparent to light radiation over its entire surface to allow very efficient irradiation, under 4pi, of the flow in order to eliminate bacteria for example. The means for generating microwaves 10a, 10b, 10c comprise a microwave energy generator 10a connected to one or more coaxial cables 10b and 10c antenna (s). for bringing the microwaves generated by the generator into the cavity. A coaxial cable - which has the particularity of being flexible - associated with an antenna is easier to arrange a waveguide - which is rigid and bulky (indeed, at least one of the characteristic dimensions of the guide is generally greater half a wavelength of microwaves). Moreover, the efficiency of a waveguide for bringing the microwaves into the cavity depends on its shape and its dimensions. On the contrary, the combination of an antenna and a coaxial cable to bring the microwaves into the cavity does not have any shape constraints. Therefore, the use of a coaxial cable 10b associated with an antenna 10c for the microwaves into the cavity 20 allows greater flexibility in the implementation of the device according to the invention. However, the device according to the invention can also be implemented with a waveguide.

The antenna 10c is preferably entirely disposed within the microwave-opaque cavity.

Thus, the channel and the external environment are completely protected from possible irradiation by microwaves.

Irradiation by the microwaves of the channel 20 can lead to interactions between the flow to be treated and the microwaves. In particular, the interaction of microwaves with a non-zero dipole moment liquid such as water, can result in:

an increase in the temperature of the liquid by absorption of the microwaves,

- A decrease in the effectiveness of the radiation of the chamber 40 due to the absorption of microwaves by the liquid to be treated. Moreover, in the case of sterilization of water, the increase of the water temperature by microwave irradiation has the disadvantage of promoting the contamination of the water.

Irradiation of the external environment by microwaves can cause serious injury to users close to the device (chromosome alterations, etc.).

In the device illustrated in FIG. 1, these drawbacks are mitigated by the presence of the annular cavity 20, which is completely closed and therefore opaque to microwaves and by the arrangement of the antenna 10c inside this cavity 20.

The various elements of the device according to the invention are arranged in such a way as to cause an enclosure in the enclosure. This allows instant ignition, for example in a millisecond. This allows multiple applications of the device according to the invention and in particular the treatment of a non-continuous flow, such as for example the sterilization of water on demand, where the device must in principle be lit only when a tap of water is open.

In the embodiment illustrated in FIG. 1, the permanent magnets 50 are disposed inside the cavity 20 and in contact with the external wall of the enclosure 40.

The magnets 50 are distributed around the enclosure 40 to homogenize the radiation of the resonance zones 80 on the irradiation channel 30.

While the walls 41 proximal (relative to the channel 30) of the chamber 40, arranged facing the channel 30, must be transparent to the light radiation, the distal walls 42 (relative to the channel 30) of the enclosure 40 can opaque to the light radiation, and preferably reflective to reflect the light radiation to the channel in which the flow flows. The cavity has proximal walls 21, with respect to the canal

30, transparent to the light radiation. However, the distal walls 22 with respect to the channel 30 of the cavity 20 may be opaque to light radiation. This is the case in particular when the plasma contained in the chamber 40 is mercury which emits light radiation in the UV range which must not leave the cavity for security reasons so as not to irradiate users close to the device.

The device illustrated in FIG. 1 further comprises means of reflection of the light radiation 60 arranged so as to direct the light radiation towards the flow to be treated.

These means of reflection of the light radiation 60 make it possible to concentrate the light radiation in the direction of the channel 30 in which the flow to be treated circulates in order to increase the effectiveness of the treatment.

In the embodiment illustrated in FIG. 1, the reflection means of the light radiation 60 are a reflective coating layer deposited on the external face of the wall of the enclosure 40 and arranged so as to reflect the light radiation towards the channel

30.

More particularly, the reflective coating layer is deposited on the portion of the outer face of the enclosure 40 furthest from the channel 30 in which the flow flows.

The device illustrated in Figure 1 can for example be integrated in the shower head with a UV blocking system to the outside, or be associated in an extremely compact system incorporating a pre-filter and an anti-scale system.

Referring to Figure 2, there is illustrated another embodiment of the device according to the invention adapted to the treatment of a liquid such as water for flow rates of between 10 and 100 m3 / h.

This embodiment differs from the embodiment illustrated in FIG. 1 in that, in this embodiment, the magnets 50 are disposed outside the cavity 20 but in contact with the cavity 20, and the enclosure 40 occupies almost the entire volume of the cavity (ie the volume of the cavity minus the volume necessary to have the antenna 10c). With such a device, it maximizes the volume of the channel directly facing the enclosure to maximize the passage time of the water in the enclosure, while minimizing the dimensions of the cavity 20.

This makes it possible to optimize the compactness of the device according to the invention.

The permanent magnets of the device illustrated in FIG. 2 are disposed outside the microwave cavity and in contact with the wall of the cavity 20 to be in immediate proximity to the chamber 40. This allows the use of non-multi-dimensional cavity size of the microwave wavelength and diameter less than 24.4 centimeters, which corresponds to twice the wavelength of microwaves at the frequency of 2.45 GHz.

Thus, preferably, each cavity 20 fits in a volume, at least one of the characteristic dimensions (height, length, width) of the smallest volume in which the microwave cavity 20 is inscribed being less than about 25 centimeters ( more precisely 24.4 centimeters), which corresponds to twice the wavelength of microwaves at the frequency of 2.45 GHz.

Those skilled in the art will appreciate that for higher frequencies, for example a frequency of 5 GHz, at least one of the characteristic dimensions of the smallest volume in which the cavity fits will preferably be less than 12 centimeters. Similarly, for lower frequencies, for example a frequency of 1 GHz, at least one of the characteristic dimensions of the smallest volume in which the cavity fits is preferably less than about 48 centimeters. Of course, it is also possible to use a microwave energy generator 10a generating microwaves at the frequency of 1 GHz or 5 GHz with a device whose characteristic dimensions of the smallest volume in which the cavity is less than 25 cm.

The magnets are distributed around the chamber to homogenize the radiation of the resonance zones on the irradiation channel.

With reference to FIG. 3, the embodiment illustrated in FIG. 1 is illustrated in cross-sectional view, which makes it possible to better appreciate the particular disposition of the permanent magnets 50 in the cavity 20. Four permanent magnets are arranged around the annular enclosure 40 located inside the cavity 20. The magnets 50 are arranged symmetrically with respect to the axis of the channel 30, and in immediate proximity to the wall of the enclosure 40.

The chamber 40 and the cavity 20 envelop a tubular channel. An antenna 10c is disposed inside the cavity 20 for the generation of microwaves.

The permanent magnets 50 generate field lines which make it possible to obtain resonance zones 80 around the channel 30 in which the flux to be treated circulates.

The wall of the enclosure 40 furthest from the channel 30 comprises a reflective coating which makes it possible to reflect the light radiation R towards the channel 30. For example, the wall farthest from the channel is made of aluminum to be opaque to microwaves and reflect the light radiation.

The proximal wall 21 of the cavity 20 is an electrically conductive mesh 23 to be opaque to microwaves and transparent to light radiation.

Alternatively, the proximal wall 21 mesh can be removed to be transparent to light radiation and microwaves, for example when the flow to be treated does not interact with the microwave (absorbing).

In this case, the device may be associated with means external to the device for avoiding irradiation of users located near the device. These external means may for example be arranged along the channel 30, at the input and at the output of the device according to the invention.

In the case of the treatment of a small flow of water flow, a device according to the variant described above can be used. However, the water interacting with the microwaves absorbing them, the effectiveness of the device is diminished, and the water is heated.

Referring to Figure 4, there is illustrated another embodiment of the device according to the invention.

This embodiment, like the embodiment illustrated in FIG. 5, is particularly suitable for the treatment of liquid such as water for flow rates of between 100 and 1000 m 3 / h.

In this embodiment, the permanent magnets 50 are disposed inside the cavity 20. This is made possible by the use of permanent magnets as means for generating the magnetic field instead of Helmholtz coils which, unlike permanent magnets, can not be disposed inside the cavity 20 because of the incompatibility between the coils and microwaves.

Moreover, the use of permanent magnets 50 disposed inside the cavity 20 makes it possible to reduce the dimensions of the device to the dimensions of the cavity 20 and thus to improve the compactness of the device, whereas the use of Helmholtz coils , necessarily placed outside the cavity, causes an increase in the dimensions of the device, the dimensions of the coils adding to the dimensions of the cavity.

In the embodiment illustrated in Figure 4, the device comprises a plurality of speakers. These speakers are associated with a plurality of permanent magnets.

The shape of the speakers illustrated in Figure 4 differs from that of the speakers illustrated in Figures 1 to 3. Indeed, in the embodiment illustrated in Figure 4, each chamber 40 has a tubular shape.

The speakers of the device illustrated in Figure 4 are arranged around the irradiation channel 30, along it. In other words, the axes of symmetry of revolution of the speakers are parallel to the axis of symmetry of revolution of the channel (when it is tubular).

In the embodiment illustrated in FIG. 4, the light ray reflection means 60 are a reflective coating layer deposited on the inner face of the outer wall of the cavity 20 and arranged so as to reflect the light radiation R towards the channel 30. More particularly the reflective coating layer is deposited on the portion of the inner face of the cavity 20 other than that directly opposite the channel 30 in which flows, which may be a grating 23. Referring to FIG. 5, there is illustrated another embodiment of the device according to the invention.

In this embodiment, the device comprises a plurality of speakers 40, cavities and antenna 10c, including four of each in Figure 5, shown in section. The cavities are arranged to surround the channel in which the flow to be treated flows. Preferably, the walls in contact with two adjacent cavities are an electrically conductive grid 24 so as to be opaque to microwaves and transparent to light radiation.

Each cavity 20 has an associated chamber 40 and an associated antenna 10c.

The enclosures 40 are arranged around the channel 30. The enclosures 40 preferably have a cylindrical tubular shape and are arranged along the channel 30, itself tubular and cylindrical.

In this embodiment, the reflection means of the light radiation 60 are independent reflectors.

Each reflector 60 is associated with a cavity 20, and comprises a reflective surface disposed facing the enclosure 40 and facing the channel 30 in which the flow flows.

The device further comprises a plurality of permanent magnets. Each cavity 20 is associated with a magnet 50. The permanent magnets 50 are disposed outside the cavities, each magnet being in contact with the outer wall of its associated cavity 20 to be in immediate proximity to its associated enclosure.

Each magnet creates a magnetic field inside the enclosure associated with it. Each antenna 10c emits microwaves into its associated cavity 20, and thus into its associated enclosure, which makes it possible to obtain the phenomenon of ECR. The fact that the device illustrated in FIG. 5 comprises a plurality of cavities makes it possible to control the distribution of the microwave power in each cavity, and thus to homogenize the radiation on all the speakers in order to optimize the irradiation of the flux.

In the embodiment illustrated in FIG. 6, the device according to the invention is used for the sterilization of water. For this use, the device comprises quick attachment means 70 for connecting the irradiation channel to a flow distribution point 80, such as a water valve. The quick fastening means 70 comprise fastening means by screwing or snap-fastening, and preferably comprise a flexible seal that is adaptable to the distribution point of the flow 80.

As illustrated in FIG. 6, the microwave energy generator 10a is disposed at a distance from the cavity 20, and connected to the cavity via a coaxial cable 10b and an antenna 10c to bring it microwaves in the cavity 20.

The device illustrated in FIG. 6 notably makes it possible to process the last drop coming out of the distribution point 80. Referring to FIGS. 7 and 8, another embodiment according to the invention is illustrated.

This embodiment is for example suitable for treating a gas. More specifically, this device is for example suitable for the treatment of air by irradiation. This embodiment makes it possible, for example, to emit light radiation (for example at a wavelength of 254 nm) on a stream of air in order to rid it of its bacteria.

In this embodiment, the walls of the irradiation channel 30 and the cavity 20 are merged. Indeed, there is no interaction between microwaves and air.

The channel 20 is for example of cylindrical shape and of any size.

The device comprises a single enclosure 40 associated with a single permanent magnet 50. The chamber 40 is disposed inside the cavity 20, and comprises for example a mercury plasma for emitting radiation at a wavelength of 254 nm bactericidal.

The inlet and the outlet of the channel 30 are closed by an electrically conductive grid to prevent microwave irradiation towards the outside of the cavity 20.

The permanent magnet 50 disposed inside the cavity 20, which increases the compactness of the device.

The device comprises means of reflections of the light radiation 60 on the internal face of the outer wall of the cavity 20. Referring to Figures 9 and 10, there is illustrated another embodiment that differs from the embodiment illustrated in Figures 7 and 8 in that in this embodiment, the permanent magnet 50 is disposed within the enclosure 40. This makes it possible to avoid shadow areas inside the cavity, and thus to increase the efficiency of the treatment device according to the invention.

Referring to Figures 11 and 12 which are views in longitudinal and transverse section, there is illustrated another embodiment of the device according to the invention. An application of this embodiment of the device according to the invention is for example the treatment of air by photo-catatlyse, using for example a TiO 2 type catalyst (titanium dioxide) which can be deposited on the internal faces of the cavity 20 or on a different support. Other types of catalyst known to those skilled in the art can be used.

This embodiment of the device according to the invention differs from the embodiment illustrated in Figures 7 to 10 in that it comprises a plurality of speakers 40 and a plurality of magnets. Each chamber is preferably tubular and contains, for example, a nitrogen plasma (for emitting UV-A and UV-B radiation which optimizes the TiO2 catalysis phenomenon).

The arrangement (in bundle) and the shape of the speakers make it possible to maximize the surface of radiation and contact between the air, the TiO2, and the UV radiation.

The permanent magnets and the speakers are disposed inside the cavity and the irradiation channel (the walls of the channel and the cavity being merged in this embodiment).

Each permanent magnet 50 is associated with at least one speaker 40. This makes it possible to further increase the compactness of the device according to the invention.

FIG. 13 shows an assembly comprising four devices D1, D2, D3, D4 according to the invention. It is thus possible to irradiate the flow flowing in irradiation channels 30, 30 ', 30 "with different light rays, that is to say with light rays having different spectra or intensities.

A control unit 18 also makes it possible to modulate the power P of the microwaves injected into the enclosure, for example in the form of pulses of any shape and frequency.

These pulses are preferably rectangular as shown in FIG. 14. The three curves P1, P2, P3 correspond to the same average power Pmn, and thus to the same average light intensity.

Indeed, according to the curve P1, a continuous power is injected into the enclosure. The continuous power Pl is equal to the average power Pmn. The average power Pmn injected is preferably between 10 and 1000 Watts. The curve P2 represents rectangular pulses having a maximum power Pmax2, for example with a frequency of 50 Hz, and having a duty cycle such that the average power Pmn injected into the chamber is the same as that of the curve P1. The curve P3 has a frequency twice as low as that of the curve P2 (in the example 50 Hz) and a maximum power Pmax3 of the rectangular pulses twice that of the curve P2.

Thus, the average power Pmn of the curves P1, P2, P3 is effectively equal. However, since the maximum powers of the curves P1, P2, P3 are different, the curves P1, P2, and P3 correspond to different light spectra.

According to a method of using at least one device according to the invention, having a predetermined light spectrum and intensity, the spectrum is controlled by the maximum power of the microwaves in the chamber and the intensity is controlled by the average power of the microwaves in the enclosure.

When several elementary devices are used as in the assembly represented in FIG. 13, the spectra and the intensities of the different devices D1, D2, D3, D4 can be controlled by means of the maximum power of the average power. time of the microwaves injected into the enclosures corresponding to the devices D1, D2, D3, D4.

The device according to the invention provides radiation in the visible spectrum and in the UV spectrum, corresponding to emission lines of the atoms and ions of the gas. The 254 nm line of the un-ionized mercury atom can be obtained with low maximum powers. A light of wavelength equal to 254 nm exhibits photo-biological effects, in particular a germicidal effect.

When the injected microwave power is increased, it is also possible to obtain emission lines of the ionized atoms having wavelengths of less than 200 nm, for example the lines of the ionized mercury once, having wavelengths of 164.9 nm and 194.2 nm. A light with these wavelengths has photochemical effects and makes it possible, for example, to generate hydroxyl free radicals by irradiation with a brightness of the order of 120 mJ / cm ² for a single given wavelength.

Thus, by switching from a power modulation such as that represented by curve P2, in FIG. 14, to a power modulation such as that illustrated by curve P3, in FIG. 14, it is possible to switch a spectrum dominated by the 254 nm line to a spectrum also showing strong emission at wavelengths below 200 nm. The choice of gas and pressure and / or temperature in the enclosure makes it possible to adapt the spectrum of the device to its use, in particular to the desired ultraviolet regime. Moreover, a 195 nm ultraviolet light makes it possible, in a known manner, to generate ozone, whereas a 254 nm ultraviolet light makes it possible to suppress ozone. Thus, it is possible to envisage a fluidic system, for example an ozone-disinfected water circuit, comprising a first device according to the invention for generating ozone and a second device according to the invention, disposed downstream of the first device (according to the flow SCF flow direction), to remove ozone so that the ozone does not come out of the whole. Only the portion of the assembly disposed between the two devices then comprises ozone, without presenting a danger for the user. The reader will appreciate that many modifications can be made to the device described above without physically going out of the teachings given here to those skilled in the art.

For example, in embodiments, the enclosure containing the plasma and the cavity are disposed within the channel. Furthermore, the number of speakers, cavities, channels, and / or permanent magnets may vary depending on the applications. Finally, in some embodiments, the device may comprise permanent magnets disposed inside and outside the cavity, in immediate proximity to at least one enclosure.

EXAMPLE OF IMPLEMENTATION

The implementation example presented below refers to Figure 1.

In this example, the flow to be treated is water. The device comprises a quartz irradiation channel (to be transparent to UV, of tubular shape, of diameter equal to 20 millimeters and length equal to 90 millimeters, ie a volume of 30 cubic centimeters for the channel).

The device also comprises a quartz enclosure, of annular shape, of external diameter equal to 60 millimeters arranged in a metal cavity (for example aluminum on the distal walls 22, and electrically conductive mesh on the proximal wall 21), also annular , with an outer diameter equal to 90 millimeters and a length of 110 millimeters, and permanent magnets in the cavity arranged in a cross-plan view around in contact with the enclosure (to respect the criterion of immediate proximity).

For a flow rate of 4 liters / hour, the water remains about 450 ms in the irradiation channel.

For a microwave power of 30 Watts, the chamber filled with a mercury plasma generates a radiation of about 10 Watts of UV at 254 nanometers.

This radiation makes it possible to reduce by 10 000 000 (log 7) the number of bacteria (for example the bacteria E.coli). The invention therefore makes it possible to obtain a very compact system since the total size of the device, which corresponds to the bulk of the cavity in this embodiment, is equal to 0.7 liters. Such a device can be placed at the end of a tap as illustrated 6.

Claims

Apparatus for the treatment of a flux by light radiation, the device comprising: microwave generation means (10a, 10b, 10c),

at least one microwave cavity (20) comprising microwave-tight walls for confining the microwaves,

at least one irradiation channel in which the flow to be treated circulates; at least one chamber containing a plasma located inside the microwave cavity;

means for generating a magnetic field (50), enclosure (s), cavity (s), and means for generating the magnetic field and microwaves being arranged in such a way as to generate a cyclotron resonance of electrons at a distance of interior of the enclosure (s) for emitting light radiation for irradiating the fluid to be treated, characterized in that the means for generating the magnetic field are constituted by at least one permanent magnet and in that each enclosure is disposed in the immediate vicinity of at least one magnet.

2. Device according to the preceding claim, characterized in that each cavity (20) fits in a volume, at least one of the characteristic dimensions (height, length, width) of the smallest volume in which the micro cavity is located. waves (20) being less than 25 centimeters.

3. Device according to one of the preceding claims, characterized in that the permanent magnet is disposed within the microwave cavity (20).

4. Device according to one of the preceding claims, characterized in that the channel (30) is disposed within the cavity (20).

5. Device according to the preceding claim, characterized in that the walls forming the cavity (20) and the walls forming the channel (30) are combined.

6. Device according to one of the two preceding claims, characterized in that the device comprises a plurality of enclosures (40) and a plurality of permanent magnets.

7. Device according to one of claims 1 to 3, characterized in that the device comprises one or more cavities (20) arranged to encompass the channel (30), the walls of (s) the cavity (s) in view of the channel being transparent to the light radiation.

8. Device according to the preceding claim, characterized in that the device comprises a cavity (20) encompassing the channel (30).

9. Device according to the preceding claim, characterized in that the channel (30) is of tubular shape, and the cavity (20) is annular.

10. Device according to the preceding claim, characterized in that the device comprises a single enclosure (40) of annular shape.

11. Device according to one of claims 7 to 9, characterized in that the device comprises a plurality of enclosures (40) around the channel (30).

12. Device according to one of the preceding claims, characterized in that each enclosure (40) is associated with a permanent magnet of its own.

13. Device according to one of claims 1 to 11, characterized in that each magnet is associated with a plurality of enclosures (40).

14. Device according to one of claims 1 to 11, characterized in that each enclosure (40) is associated with a plurality of permanent magnets.

15. Device according to one of the preceding claims, characterized in that the device comprises means for reflecting the light radiation (60) arranged to direct the light radiation to the stream to be treated.

16. Device according to one of the preceding claims, characterized in that the outer wall of the cavity (20) is opaque to light radiation.

17. Device according to one of the preceding claims, characterized in that the microwave generating means comprise a microwave energy generator (10a) and a waveguide, the waveguide being disposed between the generator and the cavity for guiding the microwaves generated by the generator towards the cavity.

18. Device according to one of claims 1 to 16, characterized in that the microwave generation means comprise a microwave energy generator (10a), at least one coaxial cable (10b), and at least one an antenna (10c), the cable (s) being disposed between the generator and the cavity, the antenna (s) being disposed inside the (or the) ) cavity (s).

19. Device according to one of the preceding claims, characterized in that each cavity (20) is associated with a single antenna (10c).

20. Device according to one of the preceding claims, characterized in that the device comprises servo means

(18), at a target light intensity, the microwave power, and / or the gas pressure and / or the temperature of the device.

21. Device according to one of the preceding claims, characterized in that the device comprises means for modulating the power of microwaves in the enclosure.

22. Device according to the preceding claim, characterized in that the power modulation means generate pulses.

23. Process for the treatment of a flux by light radiation using a device according to one of the two preceding claims, the light radiation having a predetermined light spectrum and intensity, characterized in that the method comprises a step of spectrum control as a function of the average time power of the microwaves in the enclosure and the maximum power of the microwaves in the enclosure.