FR2835517A1 - Ozone generator used for treatment of air includes unit for circulating a gas through the space between an ultraviolet tube and a tubular casing whose inner walls are reflective and made of ozone-resistant material - Google Patents

Abstract

Unit (7) for circulating a gas (3) through the space between a tubular casing (1) and a UV tube ozone generator (2) mounted in the casing transfers it from an inlet (4) for the oxygen-laden gas at one end of the UV tube to an outlet (5) for the same gas loaded with ozone at the other end. The internal walls of the casing are reflective and made of a material which is inert relative to ozone The internal walls have a roughness characterized by an arithmetic mean distance Ra of 0.05-0.5 microns. The reflective characteristics of the internal walls are obtained by polishing. The internal walls of the casing are polished and are made of austenitic stainless steel, not susceptible to intergranular corrosion and with a carbon content of less than 0.03%. In particular, the casing is made of X2CrNiMo 17-12-2 (TM) or X2CrNiMo 18-14-3 (TM) defined using European Standard EN10027. Alternatively, the austenitic stainless steel contains titanium or niobium, such as X6CrNiMoTi 17-12-2 (TM). The internal walls of the casing are polished with abrasive paper 200-1200, preferably 800-1200, and most preferably 1000-1200. Alternatively, the internal walls of the casing are polished by electrolytic treatment. The device includes a unit for cooling the UV tube. An Independent claim is given for an air treatment device containing a body (8) with an inlet (9) for the air to be treated, at least one outlet (10) for the treated air, means (7) of ensuring the air is circulated form the inlet to the outlet, and containing at least one ozone generator as described above. The inlet and outlet of the ozone generator are connected to the inlet and outlet of the air treatment device, respectively, and there is an electronic unit for controlling the amount of ozone. Three ozone generators are mounted in an air treatment device.

Description

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 The present invention relates to the technical field of ozone production.

More specifically, the subject of the invention relates to a new ozone generating device, as well as its use in different sectors and in particular, for the purification of air or water.

 Ozone occurs naturally in the atmosphere with a level at ground level varying from 0.005 to 0.05 ppm. Ozone is used at higher rates in different industrial sectors and in particular, for the disinfection of sewage and swimming pool water, the treatment of industrial waste water, the deodorization of certain industrial premises, sterilization in a medical environment or surgical, the preservation of foodstuffs, for example in cold rooms or during their transport in refrigerated trucks, the aging of wine in wine cellars, the bleaching of textile fibers and paper pulp.

 Ozone is generally produced where it is to be used. Ozone production is usually carried out using generators transforming the oxygen in the air, either by ultraviolet (UV) irradiation or by high voltage electrical discharge.

 However, the production yields obtained with such devices remain low. In addition, ozone has a strong oxidizing power and it is difficult to find ozone generators with a long lifespan.

 There is therefore a need for new ozone generating devices which can be implemented in the various applications mentioned above.

 In this context, one of the objectives of the present invention is precisely to provide a new device which is both capable of producing ozone with good yield, easy to implement and not very sensitive, even insensitive to the oxidizing power of ozone.

 The object of the invention is an ozone generator device comprising a tubular box inside which a UV ozone generator tube is mounted, and which is provided with means for connection to means ensuring the circulation of '' a gas in the chamber delimited by the box around said UV tube, between an inlet for the oxygen-laden gas, situated towards one of the ends of the UV tube, and an outlet for this same gas then loaded with ozone, situated towards the other

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 end of the UV tube. The internal walls of the box of the new device according to the invention are reflective and made of a material that is inert with respect to ozone.

 The present invention also relates to an apparatus for the treatment of air comprising an enclosure provided with at least one inlet for the air to be treated, with at least one outlet for the treated air, with means ensuring circulation air within the enclosure between the inlet and the outlet of the enclosure, comprising at least one ozone generating device according to the invention, mounted inside the enclosure, so that the the input of the device is connected to the input of the enclosure and that the output of the device is connected to the output of the enclosure, and of electronic means for regulating the ozone rate.

 Another object of the invention relates to an apparatus for treating water, comprising: - an ozone generating device according to the invention, provided at the input with means for regulating the flow rate of the gas charged with oxygen, - means to mix the water to be treated with the gas loaded with ozone opening at the outlet of the ozone generating device.

 Various other characteristics will emerge from the description given below with reference to the appended drawings which illustrate the invention and show, by way of non-limiting examples, embodiments of the subject of the invention.

 Fig. 1 is a schematic view of an apparatus for air treatment including a new device according to the invention.

 Fig. 2 shows the evolution over time, of the ozone level produced showing the influence of polishing and the nature of the material used for the internal walls of the box.

 Fig. 3 is a schematic view of an apparatus for air treatment including three devices according to the invention mounted in parallel.

 Fig. 4 is a schematic view of an installation for treating water using another alternative embodiment of a device according to the invention.

 As shown in fig. 1, the general ozone device according to the invention, designated as a whole by the reference 1 comprises as elements

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 main, a box 1 of tubular shape in which a UV tube 2, ozone generator is mounted by any suitable means. According to the example shown, the UV tube 2 is positioned in the center of the tubular box 1. The box 1 is equipped with connection means intended to be connected to means 7 ensuring the circulation of a gas 3 in the circulation chamber delimited by the tubular box 1 around the UV tube 2. To constitute a source of ozone under action of UV radiation, the wavelength of which is close to or equal to 185 nm, gas 3 must contain oxygen.

 The gas 3, charged with oxygen, enters the box 1 via an inlet 4 close to one of the ends of the UV tube 2, circulates along the UV tube 2 to exit charged with ozone on an outlet 5 located towards the other end of the UV tube 2. It can be provided that, as shown in FIG. 1, the inlet 4 and the outlet 5 are located on the lateral parts of the box. In this case, the tubular box 1 will present at each of its ends means 6 ensuring the tightness of the tube such as tight plugs which can also ensure the maintenance of the UV tube 2 inside the box 1. The holding means of the UV tube 2 preferably have an additional anti-vibration function to prevent the UV tube 2 from breaking when the device 1 is transported.

 The box 1 has a diameter which is generally in a ratio of 2 to 4 relative to the diameter of the UV tube 2, which makes it possible to concentrate the circulation of the gas 3 around the UV tube 2 and thereby improve the yield in ozone.

 According to a preferred embodiment, the device according to the invention comprises means for cooling the UV tube 2. It has been found that the temperature of the device and, in particular, that of the UV tube 2 and of the circulation chamber which l have an influence on the ozone yield.

 In operation, the device according to the invention is connected to means 7 ensuring the circulation of gas inside the box 1, of turbine type, located at the inlet and / or outlet of the device I. When these means 7 provide a sufficient gas flow, for example between 0.5 and 4.5 m3 / h, the gas flow acts as cooling means. When the gas flow is too weak to allow cooling, external cooling means can be provided.

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 The box 1 and in particular its internal walls are made of a material that is inert with respect to ozone, that is to say little sensitive to the oxidizing power of ozone.

Stainless steels can, for example, be used.

 As regards the stainless steels which can be used, reference may be made, for example, to the European specification standard EN 10088. The following steels are considered to be stainless steels, steels containing at least 10.5% chromium and at most 1, 2% carbon. Austenitic steels are particularly suitable for the invention, they contain a minimum chromium content of around 17%, nickel with a content generally greater than or equal to 7% and possible additions of molybdenum, titanium or niobium. Their resistance to corrosion increases with chromium and molybdenum contents and their resistance to corrosion with chromium content. The introduction of stabilizing elements such as titanium or nobium or the choice of a carbon content of less than 0.03% makes it possible to avoid intergranular corrosion. Furthermore, for the present invention, austenitic stainless steels which are insensitive to intergranular corrosion will be preferred. The following stainless steels: X2CrNiMo 17-12-2, X2CrNiMo 18-14-3 and X6CrNiMoTi 17-12-2 defined according to European standard EN 10027, are particularly suitable for carrying out the present invention.

 Furthermore, according to the present invention, it has been shown, surprisingly, that when the internal walls of the box are reflective, the ozone yield is greatly improved. In practice, obtaining reflective surfaces of the "mirror" type can be achieved by polishing the internal walls of the box 1 using a felt loaded with polishing paste or abrasive paper, or else a electrolytic treatment.

 The degree of polishing or the polishing grit of a surface can be defined by the particle size of the abrasives used in the surface polishing operation by abrasion. The size of the abrasive particles can vary and, generally, for the polishing grains, reference is made to a standardized code, for example grain 80 or grain 600. The size of the abrasive grains is smaller the higher the code. In particular, the mirror-type polishes according to the invention can be

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 obtained with abrasives with grains 200 to 1200, preferably from 800 to 1200 and preferably from 1000 to 1200.

 The purpose of abrasive or electrolytic polishing is to reduce the roughness of the materials used. According to the invention, stainless steels will preferably be used having a roughness characterized by an arithmetic mean difference Ra of between 0.05 and 0.5 μm. The examination of the surface condition may be carried out by any suitable means such as a roughness meter.

 Electrolytic polishing is most often used as a finish after abrasive polishing and makes it possible to improve the oxidation resistance of steel. We can also refer to the ISO 15730 standard.

The influence of the degree of polishing was highlighted by comparing the ozone yields obtained with boxes made of different materials and / or polished with different polishing grains. The experiment consists in ozonizing a room of 27 m3 whose ambient air is at a temperature of 20 C and has a hygrometry of 63%. An ozone generator is used comprising a tubular box with an internal diameter of 36 mm in which a UV tube of 15 mm in diameter is mounted by means of two teflon tips situated at the ends of the box. Sealing is ensured at each end by two O-rings. The box has an inlet for the air to be ozonated connected to a turbine propelling the air with a flow rate of 4.7 m3 / h and an outlet for the air loaded with ozone. Fig. 2 shows the ozone level (03 in ppb) produced as a function of time t (in hours) with: - a polyvinyl chloride (PVC) box: curve a - a box in stainless steel X2CrNiMo 17-12-2 no polished: curve b - and with 3 boxes 1 in accordance with the invention:. one in dry polished X2CrNiMo 17-12-2 stainless steel, with 240 grit paper: curve c. one in stainless steel X2CrNiMo 17-12-2 polished in water, with 800 grit paper: curve d. one in stainless steel X2CrNiMo 17-12-2 with a grain paste 1000-
1200: curve e

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The ozone level is measured with a device sold by the company OZONE TECHNOLOGY under the reference OS 0300 connected to an analog paper recorder.

 These results clearly show that an ozone generating device whose internal walls of the box 1 are polished makes it possible to obtain a better yield of ozone and that this yield increases with the degree of polishing.

 The present invention also relates to an apparatus II including at least one generator device 1, according to the invention and suitable for air treatment. This device II comprises an enclosure 8 provided with at least one inlet 9 for the air to be treated, at least one outlet 10 for the treated air, means 7 ensuring the circulation of the air within the enclosure between input 9 and output 10 of the enclosure. This device II also includes at least one ozone generator device 1, according to the invention, mounted inside the enclosure 8, so that the input 4 of the device 1 is connected to the input 9 of the enclosure 8, and outlet 5 of device 1 at outlet 10 of enclosure 8, and electronic means 11 for regulating the ozone level.

 It can also be provided, when the volume of air to be treated is greater, to equip the interior of the enclosure 8 with several devices 1. FIG. 3 illustrates such a variant in which three devices 1a, 1b, are mounted in parallel. In this case, each input 4a, 4b, 4e of the devices 1a, 1b, is connected to an input 9a, 9b, 9c of the enclosure 8 and the three outputs 5a, 5b, 5c of the devices 1a, 1b and are connected to the same outlet 10 of the enclosure 8. In this case, each inlet 9a, 9b, 9e, of the enclosure 1 is equipped with means 7a, 7b, 7c. The outlet 10 of the enclosure 8 is also provided with a turbine 7d, which effectively ensures the circulation of air around each UV tube 2a, 2b, 2c.

3 l'ordre de 100 m3. An apparatus II according to the invention, comprising three devices 1a, 1b and 1c is particularly suitable for treating volumes of air of the order of 300 m3 whereas an apparatus II comprising a single device 1 is more suitable for volumes of

3 in the order of 100 m3.

 Furthermore, the enclosure is provided with electronic means 11 for regulating the ozone rate. The means 11 allow, for example, to control on the one hand, the air flow inside the device 1 and on the other hand, the light intensity emitted by the UV tube 2 which, in general varies between 40 and 100% of its capacity.

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 The enclosure 8 is made of any suitable material, for example chosen from: stainless steel, metal with anti-corrosion coating. The connection between the various inputs or outputs and between the various devices 1 is made by any suitable means of the pipeline type made of a material resistant to corrosion and to the oxidizing power of ozone.

 At the input, the device II according to the invention can be equipped with filtration means and / or trapping means for the water present in the air to be treated.

 The apparatus II according to the invention is furthermore provided with suitable electrical or electronic means including supply means, optionally an operating time control and / or a safety device and / or a control of the fouling state. box 1 and UV tube 2.

 A means 12 of access to the device 1 is generally provided in order to facilitate the cleaning of the box 1 and possibly the change of the UV tube 2.

 The air treatment devices II according to the invention can be permanently fixed at their place of use or portable.

 Such devices can be used in different sectors of activity: - to suppress smoke odors after a fire, odors from fuel oil, diesel oil, cigarette smoke; - for deodorization and decontamination of premises; - for the decontamination of refrigerated trucks, cold rooms, or refrigerated displays; - to improve the conservation of fruits and vegetables; - for sterilization in a medical or surgical environment; - in a wine-growing environment, for the aging of the wine, to avoid mold on the corks, or to sterilize the barrels.

 The principle is simple, the air to be treated is sucked up to circulate inside the chamber with a "mirror" wall, around the UV 2 tube, then to come out charged with ozone, which allows in particular to have a bacteriostatic effect. .

 The electronic means 11 make it possible to regulate the flow of ozone produced according to the envisaged application. In some applications, an external sensor allowing the ozone level to be lowered at the outlet, for example once the air has been decontaminated or the bad odors have been removed, may be provided.

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 The present invention also relates to an apparatus III including at least one ozone generator device 1, in accordance with the invention and suitable for the treatment of water 13. This apparatus III comprises a device 1 according to the invention, provided at input 4 means 14 for regulating the flow of gas 3 charged with oxygen. It can be provided to use at the input 4 of the device 1 ambient air or oxygen. It is also preferable to provide a filter to remove any unwanted particles.

 The apparatus III, according to the invention also comprises means 15 for mixing the water to be treated with the gas 3 loaded with ozone emerging at the outlet 5 of the device I. It is possible to use means 15 of venturi type establishing the connection between a circuit 18 for the gas 3 loaded with ozone connected to the outlet 5, and a circuit 19 for the water to be treated connected to the casing 16 can be provided. It could also be envisaged to bubble directly the gas loaded with ozone in the water 13 to be treated.

 In the exemplary embodiment presented in FIG. 4, the device 1 has external cooling means: the box 1 is surrounded by an external envelope 16 allowing the circulation of a cooling fluid along the external walls of the box 1. The water 13 to be treated, brought in by a pump 17 can simply play the role of cooling fluid. In fact, in the case of water treatment, the gas flow 3 entering the device 1 is lower, of the order of 0.36 to 1.8 m3 / h and is therefore not sufficient to perform the function of cooling means.

 The ozone-laden water thus obtained is then carbonated in an exchange tank 20 by microbubbling.

 Conventionally, this device is coupled to a second UV tube 21 whose radiation is between 200 and 280 nm, preferably equal to 224 nm which sterilizes the water 13, thanks to the anti-germicidal and anti-bactericidal effect of such radiation.

 Before treating the water 13 using this second UV tube 21, it can be circulated through different filters 22, of the pocket filter, cartridge filter or activated carbon filter type.

 Such a device III finds a good number of applications, in particular: - for the treatment of rainwater and drawing water;

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 - for the recycling of waste water, condensate water, bottle rinser water; - for the treatment of swimming pool water; - for cold sterilization.

 The above invention is not limited to the examples described and shown, since various modifications can be made without departing from its scope.

Claims (20)

1-Device (I) ozone generator comprising a tubular casing (1) inside which a UV tube (2) ozone generator is mounted, and which is provided with means for connection to means (7 ) ensuring the circulation of a gas (3) in the chamber delimited by the box (1) around said UV tube (2), between an inlet (4) for the gas (3) charged with oxygen, located towards one of the ends of the UV tube (2), and an outlet (5) for this same gas (3) then loaded with ozone, located towards the other end of the UV tube (2), characterized in that the internal walls of the box ( 1) are reflective and made of a material inert with respect to ozone.  2-Device (I) according to claim 1 characterized in that the internal walls have a roughness characterized by an arithmetic mean difference Ra of between 0.05 and 0.5 µm.  3-Device (I) according to claim 1 or 2 characterized in that the reflecting character of the internal walls is obtained by polishing.  4-Device (I) according to claim 3 characterized in that the internal walls of the box (1) are polished and are made of austenitic stainless steel, insensitive to intergranular corrosion.  5-Device (I) according to claim 4 characterized in that the austenitic stainless steel used contains a carbon content of less than 0.03%.  6-Device (I) according to claim 5 characterized in that the austenitic stainless steel used is X2CrNiMo 17-12-2 or X2CrNiMo 18-14-3 defined according to European standard EN 10027 7-Device (I) according to claim 4 characterized in that the austenitic stainless steel used contains titanium or nobium.  8-Device (I) according to claim 7 characterized in that the austenitic stainless steel used is X6CrNiMoTi 17-12-2 defined according to European standard EN 10027.  9-Device (I) according to one of claims 3 characterized in that the internal walls of the box (1) have been polished with abrasive grains 200 to 1200, preferably 800 to 1200 and preferably 1000 to 1200.  10-Device (I) according to one of claims 3 characterized in that the internal walls of the box (1) have been polished by electrolytic treatment. <Desc / Clms Page number 11>  11-Device (I) according to one of claims 1 to 10, characterized in that it comprises means for cooling the UV tube (2).  12-Apparatus (11) for air treatment comprising an enclosure (8) provided with at least one inlet (9) for the air to be treated, with at least one outlet (10) for the treated air , means (7) ensuring the circulation of air within the enclosure between the inlet (9) and the outlet (10) of the enclosure, characterized in that it comprises at least one device (1 ) ozone generator according to one of claims 1 to 11 mounted inside the enclosure (8), so that the input (4) of the device (1) is connected to the input (9) of the enclosure (8), and that the outlet (5) of the device (1) is connected to the outlet (10) of the enclosure (8), and electronic means (11) for regulating the ozone rate .  13-Apparatus (II) according to claim 12, characterized in that three devices (la), (Ib), (le) ozone generators, are mounted inside the enclosure (8).  14- Use of a device (1) according to one of claims 1 to 11 or an apparatus (II) according to claim 12 or 13 for the decontamination of refrigerated trucks, cold rooms, or refrigerated displays.  15-Use of a device (1) according to one of claims 1 to 11 or an apparatus (II) according to claim 12 or 13 for the deodorization and decontamination of premises.  16- Use of a device (1) according to one of claims 1 to 11 or of an apparatus (II) according to claim 12 or 13 for sterilization in a medical or surgical medium.  17- Use of a device (I) according to one of claims 1 to 11 or of an apparatus (II) according to claim 12 or 13 in a wine environment for aging the wine, avoid mold on the corks, or sterilize the barrels.  18-Apparatus (III) for the treatment of water (13), characterized in that it comprises: - a device (1) according to one of claims 1 to 11 provided with input (4) of means (14 ) regulating the flow rate of the gas (3) charged with oxygen, - means (15) for mixing the water to be treated with the gas (3) loaded with ozone emerging at the outlet (5) of the device (I). <Desc / Clms Page number 12>  19-Use of a device (1) according to one of claims 1 to 11 or of an apparatus (III) according to claim 18 for the treatment of rainwater and drawing water 20-Use of a device (1) according to one of claims 1 to 11 or an apparatus (III) according to claim 18 for the treatment of swimming pool water.