FR3126189A1 - Device for treating a fluid by ultraviolet radiation - Google Patents

Abstract

The invention relates to a device for treating a fluid, in particular for the treatment of rainwater, spring or borehole water, in particular for watering farm animals and plant nutrition. The device comprises a treatment chamber 1 having a central axis (A), configured to receive the fluid along a main flow axis coinciding with the central axis, and comprising one or more emission units 2, 3 configured to emit ultraviolet rays intended for the fluid present in the chamber 1, the device comprising an electric control unit 4 configured to control the operation of the emission units 2, 3. Each emission unit 2, 3 comprises an emission loop 5, 6 centered on the central axis and oriented in a plane perpendicular to this axis, and configured to emit ultraviolet rays in at least one direction parallel to the central axis (A). Figure for abstract: Figure 3A

Description

Device for treating a fluid by ultraviolet radiation

The present invention relates to a device for treating a fluid, such as water, by ultraviolet radiation. In particular, it finds an application in the treatment of rainwater, spring or borehole water, in particular for the watering of livestock and plant nutrition.

More generally, the invention aims to be used in the fields of agriculture, leisure and industry, in all applications for disinfection of liquids transparent to ultraviolet rays. In addition to the rainwater treatment mentioned in the previous paragraph, the following other applications can be mentioned, for example:

• treatment of water from culture ponds in the fields of fish farming and aquaculture, in particular against spirulina and more generally algae;
• water treatment for swimming pools and leisure pools;
• treatment of effluents before discharge into the natural environment, such as effluents from wastewater treatment plants, or industries with discharges;
• wastewater treatment for reuse;
• treatment against legionella in industrial adiabatic installations and misting installations such as air-cooling towers or agricultural misters.

Ultraviolet radiation, which is highly energetic, is very harmful to living organisms. It is absorbed by proteins and nucleic acids (DNA and RNA) of organisms (bacteria, viruses, protists, fungi and multicellular organisms), most often causing irreversible damage at the molecular and cellular level. Ultraviolet radiation therefore has a strong germicidal power. This radiation is particularly destructive at the wavelength of 260 nm.

Devices using ultraviolet radiation make it possible to offer disinfection solutions without the use of chemicals.

Many devices are known using low and medium pressure mercury discharge lamps, emitting at a length of 254 nm, therefore close to the optimum wavelength of 260 nm.

These ultraviolet ray treatment devices with mercury discharge lamps are closed devices, operating under pressure and circulation of the fluid to be treated. They generally include an outer tube, called a shell, into which the fluid to be treated enters, and through which this fluid exits, through appropriate openings. One or more quartz tubes are arranged longitudinally in the shell, inside which are placed one or more mercury discharge lamps protected from contact with the liquid by the corresponding quartz tubes. Electronic ballasts, outside the device, are provided for the power supply of the lamps. These devices are controlled by an electronic control box.

However, these devices have drawbacks, the most problematic of which are:

• the short lifespan of mercury discharge lamps (generally 9000 hours maximum;
• the impossibility of correctly managing on/off cycles, nor of varying the power of the ultraviolet radiation according to the flow of fluid to be treated, the mercury discharge lamps having to remain constantly on;
• the inside of the grille little or difficult to visit.

The environmental impact linked to the use of mercury discharge lamps is therefore not negligible mainly due to the following two factors: the short life of the lamps, and the presence of mercury.

Other devices are also known, such as that described in the document WO2016016603, which use sources of ultraviolet rays of the LED type.

In the particular case of document WO2016016603, the fluid to be treated enters from the top of a cylindrical exchanger and flows continuously downwards, through a cylinder whose walls are lined with LEDs.

Such a device, based on the use of a large number of LEDs, has an interesting geometry, with ultraviolet radiation transverse to the fluid flow stream which touches the fluid particles. The very short residence time of the particles in the device is compensated by the power of the ultraviolet radiation resulting from the large number of LEDs distributed on the internal wall of the cylindrical exchanger.

However, such a device is relatively complex and expensive, in particular because of the number of LEDs used and their power. In particular, the cost of a small or medium-sized device, with a small or medium flow rate of fluid to be treated (less than, or of the order of, 50 m3/h), is relatively high, compared to the corresponding market. applications in which such devices can be used.

Indeed, even for small or medium flow rates, the number of LEDs used must be large for the treatment by ultraviolet radiation to be effective along the flow path of the fluid, and thus for the microbial reduction resulting from the application of ultraviolet rays is high enough.

One of the aims of the invention is therefore to solve in particular the aforementioned problems. Thus, the aim of the invention is in particular to propose a device for treating a fluid, such as water, by ultraviolet radiation, which is in particular inexpensive, simple to maintain, efficient and with a long lifespan.

The subject of the invention is thus a device for treating a fluid, such as water, comprising a treatment chamber having a central axis and configured to receive a fluid to be treated along a main flow axis substantially coinciding with the central axis, the treatment chamber comprising one or more emission units configured to emit ultraviolet rays towards a fluid present in at least a part of the treatment chamber, the device comprising an electrical control unit configured to control the operation of transmitting units.

Each emission unit comprises an emission loop centered on the central axis and oriented in a plane substantially perpendicular to the central axis, the emission loop being configured to emit ultraviolet rays, over all or part of its length , in at least one direction parallel to the central axis.

According to certain embodiments, the device also comprises one or more of the following characteristics, taken separately or in all technically possible combinations:

• the transmission loop is closed;
• the loop has one of the following overall geometries: circular, rectangular, square, ellipsoidal;
• the treatment chamber comprises an upper part in which the fluid is admitted into said treatment chamber and a lower part through which the treated fluid leaves said treatment chamber, and at least a first of the emission units is arranged in the lower part of the treatment chamber or at the interface between the lower part and the upper part of the treatment chamber;
• at least a second of the emission units is arranged in the upper part of the processing chamber;
• the treatment chamber comprises an outlet and a siphon communicating with the outlet and opening into the interior of the treatment chamber, configured on the one hand to allow the treated fluid to leave said treatment chamber, and on the other hand to create a fluid retention volume to be treated inside said treatment chamber;
• the treatment chamber comprises a diffusion plate arranged substantially perpendicular to the central axis, centered on said central axis, and separating said treatment chamber into a distribution chamber in which the fluid is admitted into said treatment chamber and a chamber reaction chamber in which the fluid leaves said treatment chamber, the diffusion plate comprising several orifices allowing the fluid to pass from the distribution chamber to the reaction chamber.
• at least some of the orifices are slots oriented and distributed circularly around the central axis along a first radius;
• at least some of the orifices are secondary orifices distributed circularly around the central axis along a second radius greater than the first radius;
• the emission loop of at least one of the emission units comprises a magnetic induction lamp and forms a continuous emission loop, preferably closed;

the emission loop of at least one of the emission units comprises a plurality of LEDs forming a discontinuous emission loop, preferably closed.

The invention also relates, according to a second aspect, to a system for treating a fluid, such as water, comprising a rigid structure on which is mounted a fluidic circuit allowing the circulation of a fluid from an inlet to an outlet, said fluidic circuit comprising one or more processing devices as presented above and arranged between said inlet of the fluidic circuit and said outlet of the fluidic circuit.

Thus, the invention exploits the principle of ultraviolet radiation for the disinfection of fluids, by proposing a device, compact with a high fluid treatment flow rate per device, therefore a low compactness/treated flow rate ratio and thus advantageous.

The device of the invention is easy to couple to other devices in parallel or in series to increase the throughput treated and/or the treatment efficiency.

The device of the invention has a high disinfection efficiency (significant microbial reduction), in particular thanks to a design which ensures that each molecule of the fluid to be treated is effectively subjected to the ultraviolet radiation generated by the corresponding source.

The device of the invention makes it possible to disinfect a fluid which passes through it, or circulating fluid, without the use of a chemical product, with the sole ultraviolet radiation produced by the emission unit(s) present in the closed enclosure formed by the treatment. The fluid is circulated by an external device such as a pump, or by gravity (gravity flow). The fluid can be pressurized, or lightly pressurized in gravity applications.

The circulation of the fluid is preferably done vertically, with entry at the top, but can follow another orientation, with a slight drop in efficiency due to the effects of gravity which depends on the flow rate and the pressure of the fluid.

The characteristics and advantages of the invention will appear on reading the following description, given solely by way of example, and not limiting, with reference to the following figures:

- Figures 1A, 2B: schematic representation of a first example of a device according to the invention, respectively without and with central outlet tube;

- Figures 2A, 2B: schematic representation of a second example of a device according to the invention, respectively without and with central outlet tube;

- Figures 3A, 3B: schematic representation of a third example of a device according to the invention, respectively without and with central outlet tube;

- Figures 4A, 4B: schematic representation of a fourth example of a device according to the invention, respectively without and with central outlet tube;

- Figures 5A, 5B: schematic representation of a fifth example of a device according to the invention, respectively without and with central outlet tube;

- : schematic representation of an example of a diffusion plate used in the variants of FIGS. 4A, 4B, 5A, 5B;

- : Schematic representation of an example of a processing system according to the invention, comprising several processing devices according to the invention.

It is specified that figures 1 to 5 (variants A and B) are all views in sections along a section plane parallel to the central axis (A) but not including this central axis (A). However, when the diffusion plate 12, which will be presented in detail later, is present, this is not presented in section to make it more visible.

As can be seen in the examples shown in the figures, the device of the invention comprises a treatment chamber 1 having a central axis (A).

This treatment chamber 1 is configured to receive a fluid to be treated along a main flow axis substantially coinciding with the central axis (A).

In the examples shown, an inlet 11 is located in the upper part of the treatment chamber 1, at the level of the central axis (A), and an outlet 9 is located in the lower part of the treatment chamber 1, at the level of the central axis (A), opposite the inlet 11. The inlet 11 allows the admission of fluid into the treatment chamber 1. The outlet 9 allows the fluid to be evacuated from the treatment chamber 1 .

The inlet 11 and the outlet 9 can be formed, for example, by union-type fittings, screw fittings, flanges, or even bare tubes.

The treatment chamber 1 comprises one or more emission units 2, 3 configured to emit ultraviolet rays intended for the fluid present in all or part of the treatment chamber 1. Thus, in the examples represented in FIGS. 1A, 1B , 2A, 2B, 4A and 4B, the processing chamber 1 comprises a single emission unit 2.

An electrical control unit 4 is provided, arranged outside the processing chamber 1 in the examples shown. This control unit 4 is configured to control the operation of the various transmission units 2, 3. This control unit 4 can be both configured for the electrical power supply of the transmission units 2, 3, and the control of the operation of these transmission units 2 2 , 3. In this case, preferably, only the power supply part is arranged outside the processing chamber 1, against or close to the latter, and the part operation control can be remoted in a separate box.

Each transmission unit 2, 3 is electrically connected to the control unit 4. This electrical connection can be obtained by sealed electrical cables, which also emerge in a sealed manner outside the processing chamber 1 (for example : use of waterproof cable gland type elements).

The operation of the emission units 2, 3 can be checked visually by means of one or more indicator lights (not shown in the figures) arranged outside the treatment chamber 1, and allowing the visible light emitted by the emission units 2, 3 but filtering ultraviolet rays, for example of the glass porthole type. These LEDs are then arranged substantially in the same plane as the transmission units 2, 3.

It is also possible to provide one or more control equipment (also not shown in the figures), for example of the ultraviolet flow sensor type, pressure sensor, temperature sensor, flow controller. These sensors can for example be installed on threaded or flanged connections outside, or even inside, the treatment chamber 1.

Each of the transmission units 2, 3 comprises a transmission loop 5, 6. Thus, in the examples shown, the transmission unit 2 comprises the transmission loop 5 and the transmission unit 3 comprises the emission loop 3. These emission loops 5, 6 are mounted on supports fixed to an internal wall of the treatment chamber. Thus, in the examples shown, the transmission loop 5 is mounted on supports 24, 25, and the transmission loop 6 is mounted on supports 26, 27.

Each of these emission loops 5, 6 is centered on the central axis (A), and oriented in a plane substantially perpendicular to this central axis (A). Furthermore, each of these emission loops 5, 6 is configured to emit ultraviolet rays, over all or part of its length, in at least one direction parallel to the central axis (A).

Each transmission loop 5, 6 is closed in the examples shown. In other variants, the loop could be slightly open.

Furthermore, in the examples shown, each transmission loop 5, 6 has a rectangular overall geometry, possibly square. In other variants, the overall geometry of one or the other of the transmission loops 5, 6 could be circular or ellipsoidal.

More specifically, in the examples shown, each emission loop 5, 6 takes the form of a tubular magnetic induction lamp, of circular section, and forms a continuous loop, preferably closed, maintained in the treatment chamber 1 by supports 24, 25, respectively 26, 27, of suitable shape.

Each emission loop 5, 6 therefore emits, continuously over its entire length, ultraviolet rays in at least one direction parallel to the central axis (A). More specifically, in the examples shown, each emission loop 5, 6 emits, continuously over its entire length, ultraviolet rays in all directions.

In other examples not shown, one or more of the emission loops can comprise a plurality of LEDs distributed so as to form a discontinuous loop, preferably closed. The LEDs are then positioned so as to emit ultraviolet rays in at least one direction parallel to the central axis (A). The emission loop(s) concerned therefore emit, discontinuously over their entire length, ultraviolet rays in at least one direction parallel to the central axis (A).

As can be seen in the examples shown in the figures, at least one first transmission unit 2 is arranged in the lower part 8 of the processing chamber 1 (FIGS. 2A, 2B, 3A, 3B, 4A, 4B), or at the interface between the lower part 8 and the upper part 7 of the treatment chamber 1 (FIGS. 1A, 1B).

In the examples shown in Figures 1A, 1B, 2A, 2B, 4A, 4B, a single transmission unit 2 is used.

In the examples shown in Figures 3A, 3B, 5A, 5B, a second transmission unit 3 is arranged in the upper part 7 of the processing chamber 1.

It is possible to use a siphon 10, to allow retention of the fluid in the treatment chamber 1, while also ensuring the evacuation of the fluid through the outlet 9.

Specifically, provision can be made for the treatment chamber 1 to have a siphon 10 communicating with the outlet 9 and opening inside the treatment chamber 1. Such a siphon is configured on the one hand to allow the treated fluid to leave the chamber treatment chamber 1, and on the other hand to create a fluid retention volume to be treated inside said treatment chamber 1.

This siphon 10 can take different forms. In the examples illustrated in FIGS. 1B, 2B, 3B, 4B and 5B, it takes the form of an outlet tube 10 connected to the outlet 9, in the lower part 8 of the processing chamber 1, and emerging at the inside this treatment chamber 1.

Other types of siphons or constructions providing the siphon function can be used, such as a double-walled processing chamber 1 configuration.

In the case of a siphon 10 in the form of an outlet tube, this may be axial as illustrated in the figures, or even offset, oblique, angled, etc. The outlet 9, positioned at the level of the central axis (A) in the examples illustrated in the figures, can itself be offset in other examples.

The siphon 10 is particularly suitable for flow situations in which the device is likely to completely empty when the flow stops, such as low pressure, gravity flow.

The device of the invention can operate under pressure, or even at low pressure, in gravity flow for example. In pressure flow, the device can operate in any position, although use in a vertical orientation with the inlet 11 at the top is preferred. In low-pressure, gravity-type flow, operation must be done in vertical orientation, with inlet 11 at the top.

As can be seen in the figures representing the examples concerned, the outlet 9 and the outlet tube 10 are arranged on the central axis (A).

In the following, various possible configurations, illustrated in the figures, are presented in which a siphon is present in the form of the outlet tube 10. However, all of the following considerations concerning the outlet tube 10 also apply. when the treatment chamber 1 comprises another type of siphon than the outlet tube 10. Thus, when it is indicated that the outlet tube 10 opens in a certain way into, or in a certain area of, the treatment 1, this means more generally, when the treatment chamber 1 comprises another type of siphon, that the latter opens in the said way into, or in the said zone of, the treatment chamber 1.

In the examples shown in Figures 1B, 2B and 3B, the outlet tube 10 opens into the upper part 7 of the treatment chamber 1.

In the examples shown in Figures 4B and 5B, the outlet tube 10 opens into the lower part 8 of the treatment chamber 1.

Preferably, when the treatment chamber 1 comprises a single emission unit 2, as in the examples represented in FIGS. 1B, 2B and 4B, the outlet tube 10 opens above this single emission unit 2. Alternatively, it could just as well open out to the same level as this single emitting unit 2.

Preferably again, this time when the treatment chamber 1 has a plurality of emission units 2, 3, the outlet tube 10 emerges either at the level of, or above, the emission unit which is located closest to the inlet 11 of the processing chamber 1. Thus, in the example with two emission units 2, 3 represented on the , the outlet tube 10 emerges at the level of the second transmission unit 3.

It is possible to place in the treatment chamber 1 a diffusion plate 12, an example of which is illustrated in the .

This diffusion plate 12 is arranged substantially perpendicular to the central axis (A), centered on the latter, and separates the treatment chamber 1 into a distribution chamber and a reaction chamber. When the diffusion plate 12 is arranged at the interface between the upper part 7 and the lower part 8 of the interior chamber 1, as illustrated in the examples represented in FIGS. 4A, 4B, 5A, 5B, the distribution chamber 7 coincides with the upper part 7 and the reaction chamber 8 coincides with the lower part 8.

This diffusion plate 12 comprises several orifices 13, 14 allowing the fluid to pass from the distribution chamber 7 to the reaction chamber 8.

More specifically, in the examples shown in Figures 4A, 4B, 5A, 5B and 6, a series of first orifices 13 correspond to slots 13. These slots 13 are oriented and distributed circularly around the central axis (A) according to a first ray.

It is also possible to provide a second series of orifices 14, or secondary orifices 14, distributed circularly around the central axis (A) according to a second radius greater than the first radius.

The diffusion plate 12 makes it possible to distribute all the flow around the periphery of the chamber of the distribution chamber 7 and to inject it into the reaction chamber 8 through slots 13 and possibly secondary orifices 14.

Indeed, the diffusion plate 12 creates moderate turbulence in the treatment chamber 1 and homogenizes the fluid mixture to be treated/microbial particles.

Thanks to the diffusion plate 12, the speed of each particle is almost identical everywhere, and almost equal to the average speed of the flow. Thus, all the particles have an almost identical residence time and therefore undergo the same amount of ultraviolet radiation.

However, in the case of high flow rates, the pressure drop caused by the diffusion plate 12 can make the advantage procured by this diffusion plate 12 questionable, in terms of effectiveness and optimization of the treatment by ultraviolet radiation. It is therefore absent from the examples represented in FIGS. 1A, 1B, 2A, 2B, 3A, 3B, which thus correspond to configurations for high flow rates.

Indeed, the applicant has determined that beyond a threshold value of the Reynolds number corresponding to a given device, calculated in particular from the flow rate of the fluid to be treated, its density, its dynamic viscosity and the diameter hydraulics of the device, the diffusion plate 12 generates pressure drops.

The diffusion plate 12, when present, is for example flanged in a sealed manner between the upper part 7 and the lower part 8 of the treatment chamber 1.

If a diffusion plate 12 is used together with an outlet tube 10 opening into the upper part 7, or distribution chamber 7, of the treatment chamber 1, a hole can be provided in this diffusion plate 12 adjusted to the ascent from the outlet tube 10.

The emission unit(s) 3 possibly present in the distribution chamber 7 can then continue to ensure the microbial barrier in the retention volume, even in the absence of flow.

The device of the invention, which is particularly compact and easy to use, can be mounted in a system for treating a fluid such as water, as illustrated in the example represented on the .

Such a system comprises a rigid structure 15 on which is mounted a fluid circuit allowing the circulation of the fluid to be treated from an inlet 16 to an outlet 17. This fluid circuit actually comprises one or more treatment devices 18 to 21 according to the invention, arranged between inlet 16 and outlet 17.

The treatment devices 18 to 21 can be connected in series and/or in parallel, to increase the flow rate of fluid treated and/or the efficiency of the treatment in terms of microbial reduction.

To facilitate the circulation of the fluid to be treated in the fluidic circuit, one or more pumps 22 are provided, between the inlet 16 and the treatment devices 18 to 21. Other devices, such as filtering devices, can also be mounted on the rigid structure 15, connected in the fluidic circuit.

An electronic control unit 23 is also mounted on the rigid structure 15, connected to the various elements, to control their operation.

It is recalled that the present description is given by way of example and does not limit the invention. In particular, the invention is not limited to a device whose treatment chamber has a specific shape. Similarly, the invention is not limited to a device having a determined number of ultraviolet ray emission units.

Furthermore, the invention is not limited either to the use of a particular source of ultraviolet rays.

Claims (10)

Device for treating a fluid, such as water, comprising a treatment chamber (1) having a central axis (A) and configured to receive a fluid to be treated along a main flow axis substantially coinciding with the central axis (A), the treatment chamber (1) comprising one or more emission units (2, 3) configured to emit ultraviolet rays towards a fluid present in at least part of the treatment chamber ( 1), the device comprising an electrical control unit (4) configured to control the operation of the transmission units (2, 3),
characterized in that each transmission unit (2, 3) comprises a transmission loop (5, 6) centered on the central axis (A) and oriented in a plane substantially perpendicular to the central axis (A), and in that said emission loop (5, 6) is configured to emit ultraviolet rays, over all or part of its length, in at least one direction parallel to the central axis (A). Device according to Claim 1, characterized in that the transmission loop (5, 6) is closed. Device according to any one of Claims 1, 2, characterized in that the loop (5, 6) has one of the following overall geometries: circular, rectangular, square, ellipsoidal. Device according to any one of Claims 1 to 3, characterized in that the treatment chamber (1) comprises an upper part (7) in which the fluid is admitted into the said treatment chamber (1) and a lower part (8 ) through which the treated fluid leaves said treatment chamber (1), and in that at least a first of the emission units (2, 3) is arranged in the lower part (8) of the treatment chamber (1 ) or at the interface between the lower part (8) and the upper part (7) of the treatment chamber (1). Device according to Claim 4, characterized in that at least a second of the transmission units (2, 3) is arranged in the upper part (7) of the treatment chamber (1). Device according to any one of Claims 1 to 5, characterized in that the treatment chamber (1) comprises an outlet (9) and a siphon (10) communicating with the outlet (9) and emerging inside the treatment chamber (1), configured on the one hand to allow the treated fluid to leave said treatment chamber (1), and on the other hand to create a fluid retention volume to be treated inside said treatment (1). Device according to any one of Claims 1 to 6, characterized in that the treatment chamber (1) comprises a diffusion plate (12) arranged substantially perpendicular to the central axis (A), centered on this said central axis ( A), and separating said treatment chamber (1) into a distribution chamber (7) in which the fluid is admitted into said treatment chamber (1) and a reaction chamber (8) in which the fluid leaves said treatment (1), the diffusion plate (12) comprising several orifices (13, 14) allowing the fluid to pass from the distribution chamber (7) to the reaction chamber (8). Device according to Claim 7, characterized in that at least some of the orifices (13, 14) are slots (13) oriented and distributed circularly around the central axis (A) along a first radius. Device according to Claim 8, characterized in that at least some of the orifices (13, 14) are secondary orifices (14) distributed circularly around the central axis (A) according to a second radius greater than the first radius. System for treating a fluid, such as water, comprising a rigid structure (15) on which is mounted a fluidic circuit allowing the circulation of a fluid from an inlet (16) to an outlet (17), said fluidic circuit comprising one or more processing devices (18 to 21) according to any one of claims 1 to 9 disposed between said fluidic circuit inlet (16) and said fluidic circuit outlet (17).