Device for air purification by photocatalysis, and air treatment apparatus

Abstract

The present invention relates to an air purification device (1) comprising a foam pad (3) that accommodates at least one light guide (5), the foam pad (3) being formed of photocatalyst fibres, the light guide (5) being configured to be supplied with light by a light source, and the light guide (5) having lateral light scattering means (8) in order to scatter light laterally with respect to the direction of movement of the light in the light guide (5). The invention also relates to an air treatment apparatus comprising an air purification device (1) of this kind.

Description

[0001] DESCRIPTION

[0002] TITLE: PHOTOCATALYTIC AIR PURIFICATION DEVICE AND AIR TREATMENT APPARATUS

[0003] FIELD OF THE INVENTION

[0004] The present invention relates to the field of depollution and purification of indoor air in homes, and in particular to an air purification device as well as to an air treatment apparatus equipped with such an air purification device.

[0005] It will be noted that, in this document, the terms "longitudinal", "transverse", "perpendicular", "parallel", "rotation", "horizontal", "vertical", "lower", "upper", "high", "lower", "secant", "coaxial", "convex", "concave", "plane" used to describe the apparatus according to the invention, refer to this device in a situation of use, when it is placed on a horizontal plane.

[0006] Pollutants are mainly composed of two categories. One includes particulate pollutants such as dust, bacteria, and molds, which are large in shape and have complex molecular structures, ranging in size from 0.01 micrometers to several hundred micrometers. The other category includes gaseous pollutants, for example, volatile emanations perceived by the sense of smell, such as odors, or volatile organic compounds (VOCs) such as chemical compounds, generally with a simple chemical structure. Gaseous pollutants can be composed of a variety of chemical elements. Their size is small and varies from a few angstroms to a few nanometers.

[0007] Advanced Oxidation Techniques (AOT) are used to oxidize volatile organic compounds (VOCs). The most effective are those that lead to the formation of hydroxyl radicals OH*, which have a higher oxidizing power than traditional oxidants. This is the case of photocatalysis. Photocatalysis consists of irradiating a semiconductor material (such as TiO2), which will allow the oxidation or reduction of VOCs in contact with the photocatalytic material. The energy provided by the light activates the semiconductor. The semiconductor is considered a catalyst.The principle is based on the absorption of a photon by the semiconductor solid, leading to the promotion of an electron from the valence band to the conduction band by releasing a vacancy, and thus forming free radicals which will either react with compounds present in the surrounding environment or recombine following various mechanisms, thus giving the solid oxidizing and reducing properties. Most organovolatile compounds as well as many pesticides, herbicides, surfactants and dyes are completely oxidized into less toxic products by this technique, until carbon dioxide CO2 and water H2O are obtained.

[0008] The main VOCs in ambient air are: formaldehyde, acetaldehyde, acetone, heptane, alcohols including isopropanol, decane, benzene, toluene.

[0009] STATE OF THE ART

[0010] Filters for treating VOCs, such as activated carbon filters, are known. Such filters are, for example, integrated into air treatment units. However, these filters have a limited lifespan and must be replaced regularly. Furthermore, replacing these filters is expensive, and they are generally not recyclable.

[0011] Air treatment devices that use photocatalysis technology are also known. However, these devices often release VOCs when, on the contrary, they are supposed to eliminate them and purify the air. It is difficult to understand why an air purifier or air purifier releases VOCs even if the VOCs released are different in nature and / or quantity from what was initially present in the air before purification. The major disadvantage of these devices is therefore the production of by-products, which can sometimes be more dangerous than the initial molecules, for example heptane, which can form formaldehyde when degraded. To reduce the formation of these toxic by-products, known air treatment devices propose lowering the operating speed (gas speed or light intensity) until the VOC content in the air to be purified drops below a certain value.It is also unfortunate that the air treatment unit cannot be operated precisely when it is needed most, i.e., when there is a high concentration of VOCs. As a result, gaseous pollutants cannot be absorbed and removed effectively. In addition, the accumulation of particulate pollutants on the surface of the gaseous removal filter could lead to other problems, such as the appearance of incubation zones for bacterial growth, or a loss of filter efficiency over time.

[0012] STATEMENT OF THE INVENTION

[0013] The invention proposes to resolve these drawbacks by proposing an air purification device that is made in a simple manner while being permanently effective in eliminating pollutants such as VOCs.

[0014] According to a first aspect, the invention proposes an air purification device, comprising a cotton pad receiving at least one light guide, the cotton pad being formed from photocatalyst fibers, the light guide being configured to be supplied with light by a light source, and the light guide having lateral light diffusion means in order to diffuse light laterally relative to the direction of movement of the light in the light guide.

[0015] Thus, the air purification device is produced in a particularly simple manner while being particularly effective in removing pollutants such as VOCs. Indeed, the arrangement in the form of a cotton pad formed from photocatalyst fibers and receiving at least one light guide, makes it possible to maximize photocatalysis while being simple to manufacture, by maximizing the probability that polluted air encounters a photocatalytic site activated by light, by significantly increasing the contact time of the pollutants with photocatalytic sites. Thus, a single assembly, namely the assembly of the cotton pad and the light guide, makes it possible to carry out photocatalysis. Such an air purification device also has the advantage of being permanent, and does not require regular replacement.Thus, a device, for example an air treatment device, equipped with such an air purification device, is easier to maintain, since it does not require regular replacement of the air purification device.

[0016] According to a second aspect, the invention also proposes an air treatment apparatus comprising:

[0017] - an air circulation duct between an air inlet and an air outlet,

[0018] - a light source, and

[0019] - an air purification device as previously described and arranged in the air circulation duct, in which the light guide is supplied with light by the light source.

[0020] The invention is advantageously and optionally supplemented by the following characteristics, taken alone or in any of their technically possible combinations:

[0021] - The photocatalyst consists of at least one photocatalyst material.

[0022] - The photocatalyst consists only of photocatalyst material. These can be the same or different photocatalysts.

[0023] - The photocatalyst is formed solely of at least one catalyst material with photocatalytic action.

[0024] - The photocatalyst is a catalyst with photo-catalytic action, which is not metallic.

[0025] - Photocatalyst fibers are not metallic.

[0026] - Photocatalyst fibers are made of photocatalyst only.

[0027] - Photocatalyst fibers exclude any material other than the photocatalyst, with the exception of materials inherent in the photocatalyst manufacturing process. - Photocatalyst fibers include the photocatalyst in their mass.

[0028] - The cotton wool cushion is made of photocatalyst fibers. These can be the same or different photocatalyst fibers.

[0029] - The cotton pad is made only of photocatalyst fibers.

[0030] - The cotton pad made of photocatalyst fibers is not a pad coated with photocatalyst but a pad made of photocatalyst fibers.

[0031] - The photocatalyst fibers are preferably obtained by a continuous preparation process where a photocatalyst dispersion is extruded and solidified. Preferably, the photocatalyst dispersion is an aqueous dispersion of at least one vinyl alcohol polymer. Advantageously, the extrusion of the photocatalyst dispersion is carried out continuously and unidirectionally in a bath capable of causing the fiber to solidify. Washing and drying steps may be envisaged. Thus, a photocatalyst fiber is obtained, the length of which can reach several hundred meters.

[0032] - The wadding cushion has a thickness less than its other dimensions, for example its longitudinal and transverse dimensions, thickness in which the at least one light guide is received.

[0033] - The wadding cushion is formed in its thickness by two half-wadding cushions, between which at least one light guide is received.

[0034] - The wadding cushion is obtained from a textile sheet comprising fibers formed from photocatalyst, preferably by fluffing.

[0035] - The textile sheet comprises the light guide, the light guide preferably comprising at least one optical fiber. - The light guide is formed from a material selected from the group comprising polymethyl methacrylate (PMMA), polycarbonate (PC) and cycloolefins (COP), preferably polycarbonate (PC).

[0036] - The lateral light diffusion means are formed by surface alterations of the light guide. Thus, the lateral light diffusion means are produced in a particularly simple manner.

[0037] - One end of the light guide is configured to be arranged opposite a light source to transmit light and laterally emit light at the lateral light diffusion means to activate the photocatalyst.

[0038] - Surface alterations to the light guide can be carried out in various ways, including sandblasting, chemical etching, or melting using high-intensity light radiation such as a laser. Of course, such alterations can also be carried out by many other mechanical or chemical processes.

[0039] - The surface alterations of the light guide can be distributed symmetrically or asymmetrically (for example progressively). Indeed, in order to achieve homogeneous illumination of the cotton pad, and therefore homogeneous activation of the photocatalyst in the cotton pad, the surface density or the dimension of the alterations can vary from one zone to another of the light guide. For example, the surface density of the alterations is low on the side of the light source and increases as one moves away from the light source.

[0040] - The light guide passes through the wadding pad. This reinforces the structural integrity of the wadding pad.

[0041] - The light guide includes at least one optical fiber.

[0042] - The light guide is a sheet, preferably formed from optical fibers.

[0043] - The cotton wool cushion accommodates several light guides. Thus, the presence of several light guides makes it possible to improve the efficiency of photocatalysis in a particularly simple way. Such an arrangement is therefore particularly effective in eliminating pollutants such as VOCs.

[0044] - The light guides received in the cotton pad are coplanar. Thus, the distribution of light within the cotton pad is optimized.

[0045] - The light guides housed in the cotton pad are equidistant. This optimizes the light distribution within the cotton pad, ensuring that the minimum effective dose of light is produced throughout the entire cotton pad.

[0046] - The light guides are powered by a single light source. This simplifies manufacturing, as only one light source is used.

[0047] - A first of the light guides passes through the cotton pad, preferably a second of the light guides is arranged against an external surface of the cotton pad, and preferably a third of the light guides is arranged against another surface of the cotton pad opposite the external surface.

[0048] - A guide assembly comprises a trunk from which several branches extend, each branch forming a light guide, the light source feeding the guide assembly at a single light input of the trunk. Thus, photocatalysis is optimized in a simple way.

[0049] - The guide assembly has a fork shape. This optimizes light distribution and photocatalysis while maintaining a simple guide assembly shape, making it easier to manufacture.

[0050] - The guide assembly is formed from the same material, preferably entirely from a single piece. This simplifies manufacturing.

[0051] - The air purification device further comprises means for holding the cotton pad in position, the means for holding it in position preferably comprising a cartridge. Thus, the air purification device is of modular design, which facilitates its assembly or integration into a device, such as an air treatment device.

[0052] - The photocatalyst is activated by light, which may be of the ultraviolet type, via the light guide(s) configured to guide the light inside the cotton pad. Simply cutting the cotton pad to the dimensions of the air purification device or the means for holding it in position makes it possible to produce purification devices of any size.

[0053] - The wadding cushion has a transverse dimension less than or equal to 20 centimeters.

[0054] - The wadding cushion has a longitudinal dimension less than or equal to 1 meter.

[0055] - The photocatalyst fibers have a smaller dimension of at least 10 micrometers. Thus, the resistance of the cushion formed by the photocatalyst fibers is improved.

[0056] - The photocatalyst fibers are macroscopic. For the purposes of the present invention, the term macroscopic fiber means a strand in which the smallest dimension is at least 10 micrometers. Preferably, the strand has two average dimensions orthogonal to its longitudinal axis, the first average dimension (corresponding to its width) varies from 30 to 60 micrometers, preferably from 40 to 50 micrometers, and the second average dimension (corresponding to its thickness) varies from 10 to 40 micrometers, preferably from 10 to 20 micrometers.

[0057] - The photocatalyst is a semiconductor material. Thus, the photocatalyst is made in a simple way.

[0058] - The photocatalyst comprises at least one oxide chosen from the group consisting of TiO2, ZnO, CeO2. Thus, the photocatalyst is produced in a simple manner while being particularly effective.

[0059] - The photocatalyst comprises at least partially crystalline TiO2, preferably predominantly crystalline TiO2. Thus, the photocatalyst is particularly effective.

[0060] - The air purification device comprises several cotton pads arranged one above the other, with or without contact, each cotton pad receiving at least one light guide, each cotton pad being formed of photocatalyst fibers. Thus, the presence of several cotton pads makes it possible to improve the efficiency of photocatalysis in a particularly simple manner. Such an arrangement is therefore particularly effective for removing pollutants such as VOCs.

[0061] - The wadding cushions are arranged in parallel layers, preferably flat or non-flat.

[0062] - The wadding cushions are curved.

[0063] - The cotton pads are spaced apart by at least a predetermined value such that air to be purified circulates between the cotton pads, preferably the predetermined value being greater than or equal to 5 millimeters. Thus, the spacing of a predetermined value present between the cotton pads increases the efficiency of the air purification device, such an air purification device making it possible to purify a high air flow rate while being of compact construction. The air to be purified circulates between the cotton pads in order to come into contact with the photocatalyst. Advantageously, the air circulation is carried out according to a low but swirling medium flow rate. These cotton pads allow the air to circulate along the cotton pads and / or between the cotton pads, in a direction parallel to the cotton pads. This makes it possible to maximize the contact of the air to be purified with the photocatalyst.If the cotton pads are too far apart, the air only circulates in a laminar manner and the probability of air contact with the photocatalyst is reduced, decreasing the purification efficiency. Advantageously, the cotton pads are close enough together to maximize air contact with the photocatalytic surface, and cause vortices in the airflow. Advantageously, the cotton pads are close enough together to maximize air contact with the photocatalytic surface, and cause vortices in the airflow.

[0064] - The wadding cushions are directly superimposed on each other. Thus, the air to be purified necessarily passes through the wadding cushions, and the photocatalytic action is improved. - Other arrangements of the wadding cushion(s) can be envisaged, for example in the form of rolls where each wadding cushion is rolled on itself like a roll of carpet.

[0065] - The light source may be composed of several identical or different light sources, which may be of different natures, and in particular be in the form of light-emitting diodes (LEDs) or extended sources such as incandescent lamps, fluorescent tubes or discharge tubes incorporating a gas such as neon.

[0066] - The light source supplies light to one end of the light guide.

[0067] - The air treatment unit includes several air inlets, identical or different.

[0068] - The air treatment unit includes several air outlets, identical or different.

[0069] - The air treatment device is a domestic appliance comprising a casing forming the outer casing of the air treatment device.

[0070] - The air treatment unit is configured to be movable during operation. This simplifies handling and movement of the unit. In fact, the air treatment unit is movable and not fixed to a support. Thus, the air treatment unit can be carried by a user in order to move it, either by pushing it with the foot or by grasping it with the hands, whether the air treatment unit is in operation or not.

[0071] - The air handling unit is an individual domestic appliance and not a centralized air conditioning system, for example in a hospital, airport, shopping center, metro or train station.

[0072] - The air treatment unit is a portable, individual device suitable for small spaces such as a single-family home or a caravan. - The light source is a UV light source. Thus, the photocatalytic action is carried out in a simple yet particularly effective manner.

[0073] - The light source may comprise a collector capable of focusing natural solar light in a point or linear manner towards at least one end of at least one light guide.

[0074] - The light source is made of an LED. This makes the light source simple to design and yet particularly effective.

[0075] - The light source can be made with a UVA, UVB or UVC LED. Such a system allows to combine minimal energy consumption with significant efficiency.

[0076] - The air treatment apparatus further comprises a volatile organic compound analyzer and an automatic adjustment member, which is configured to automatically adjust, depending on the volatile organic compound content analyzed by the analyzer, the speed of the air entering the air inlet and / or the light intensity of the light source.

[0077] - The cotton pad is arranged parallel to the air flow in the air circulation duct. Thus, the air flow passes through and / or flows along the cotton pad, in other words tangentially to it, and the photocatalytic action is improved.

[0078] - The cotton pad is arranged transversely to the air flow in the air circulation duct. Thus, the air flow necessarily passes through the cotton pad, and the photocatalytic action is improved.

[0079] - The air treatment device further comprises a particle filter. Such a particle filter separates particles from the air by mechanical action, retaining on the surface particles whose diameter is greater than the diameter of the pores of the filter and being able to retain particles whose diameter is smaller than that of the pores of the filter by the action of electrostatic forces. - The particle filter is arranged, according to the movement of the air between the air inlet and the air outlet, upstream of the air purification device. Thus, the air purification device does not become clogged with particles.

[0080] - The particle filter is a HEPA filter, an acronym for High Efficiency Particulate Air. The HEPA filter is preferably capable of filtering, in one pass, at least 99.97% of particles with a diameter greater than or equal to 0.3 micrometers.

[0081] - The air treatment unit also includes an activated carbon filter. This allows the air purification device to more effectively remove pollutants that pass through the activated carbon filter. Activated carbon filters were developed in response to industrial emissions of volatile organic compounds (VOCs). In an activated carbon adsorption system, contaminated air is directed over a bed of carbon. The carbon extracts the VOCs from the air and adsorbs them, holding them on the surface.

[0082] - The activated carbon filter is positioned downstream of the air purification device, depending on the air movement between the air inlet and the air outlet. Thus, the activated carbon filter eliminates "by-product" pollutants passing through the air purification device, which could be produced exceptionally (for example, in connection with an abnormal peak in pollutant concentrations). Activated carbon filters were developed in response to industrial emissions of volatile organic compounds (VOCs). In an activated carbon adsorption system, contaminated air is directed onto a bed of carbon. The carbon extracts the VOCs from the air and adsorbs them, keeping them on the surface. Since this activated carbon filter is only present to act exceptionally, it is a permanent part of the device, and not a consumable.

[0083] - The air treatment device further includes a formaldehyde filter. Thus, any formaldehyde that might exceptionally escape from the air purification device would be captured. - The air treatment device further includes a dehumidifier. Such a dehumidifier serves to reduce the moisture content of the air and increases the efficiency of the air treatment device.

[0084] - The air treatment apparatus further comprises an air moving member configured to move air from the air inlet to the air outlet. Thus, the air movement is forced between the air inlet and the air outlet.

[0085] - The air movement member is, for example, a radial flow or mixed flow turbine, or a fan, arranged downstream of the air purification device. In this case, a motor fan unit may be arranged on the air outlet side, above the air purification device.

[0086] - The air treatment device further comprises one or more fans, agitators or tabulators. Thus, the presence of one or more fans, agitators or tabulators makes it possible to generate turbulence in the air flow passing through the air purification device, for example so as to generate vortices between the cotton pads, which further increases its efficiency.

[0087] - The air treatment unit has a volume of less than 1 m 3 , preferably less than 0.8 m 3 , more preferably less than 0.6 m 3 .

[0088] - The air treatment device has a mass less than or equal to 30 kg, preferably less than 20 kg, more preferably less than 6 kg.

[0089] - The air treatment unit has an apparent cotton pad surface area of ​​at least 4000 cm 2 , preferably at least 6000 cm 2, more preferably at least 8000 cm 2 . By visible surface, we mean the surface of the wadding cushion in contact with the air flow.

[0090] - The air flow moving in the air purification device has a speed of less than 1 m / s, preferably less than 0.5 m / s, more preferably less than 0.2 m / s. - A contact time of the pollutants with the cotton pad is at least 0.5 s and can be as long as possible, this for example thanks to a flow of the air flow through the cotton pad, either parallel to the light guide or orthogonal to the light guide, or thanks to a swirling flow of the air flow to be treated. Thus the air flow to be treated has a rotational speed at all points. The swirling flow makes it possible to increase the average contact time between the air to be treated and the air purification device. The longer the contact time, the less risk there is of producing polluting by-products.

[0091] DESCRIPTION OF FIGURES

[0092] Other characteristics, aims and advantages of the invention will emerge from the detailed description below, which is purely illustrative and non-limiting, and which must be read in conjunction with the appended drawings, given as non-limiting examples and in which:

[0093] [Fig. 1] is a schematic perspective view of an exemplary embodiment of the air purification device;

[0094] [Fig. 2] is a top view of an exemplary embodiment of a light source supplying light to the air purification device;

[0095] [Fig. 3] is a schematic perspective view of an alternative embodiment of the air purification device;

[0096] [Fig. 4] is a schematic perspective view of an exemplary embodiment of an air treatment apparatus comprising an air purification device;

[0097] [Fig. 5] is a schematic diagram of the air circulation in the air handling unit;

[0098] [Fig. 6] is a schematic diagram of the air circulation in the air purification device of the air treatment unit.

[0099] Throughout the figures, similar elements are designated by identical references.

[0100] DETAILED DESCRIPTION OF THE INVENTION Figure 1 shows an air purification device 1. The air purification device 1 comprises at least one cotton pad 3 receiving at least one light guide 5.

[0101] For example, the cotton pad 3 receives several light guides 5.

[0102] In the example illustrated in Figure 1, the air purification device 1 comprises a cotton pad 3, which receives several light guides 5.

[0103] The wadding pad 3 is formed from photocatalyst fibers. The wadding pad 3 preferably has a thickness less than its other dimensions, for example its longitudinal and transverse dimensions, thickness in which the at least one light guide 5 is received. Advantageously, the wadding pad 3 has a transverse dimension less than or equal to 20 centimeters and a longitudinal dimension less than or equal to 1 meter.

[0104] In the example illustrated in Figure 1, the light guides 5 received in the wadding cushion 3 are coplanar. Furthermore, the light guides 5 received in the wadding cushion 3 are preferably equidistant.

[0105] Preferably, each light guide 5 passes through the cotton pad 3.

[0106] Furthermore, each light guide 5 has lateral light diffusion means 8 in order to diffuse light laterally relative to the direction of movement of the light in the light guide 5.

[0107] Each light guide 5 is configured to be supplied with light by a light source 9, as shown for example in FIG. 2. One end of each light guide 5 is for example configured to be arranged opposite the light source 9 to transmit the light and emit light laterally at the level of the lateral light diffusion means 8 to activate the photocatalyst.

[0108] For example, each light guide 5 is formed from a material selected from the group comprising polymethyl methacrylate (PMMA), polycarbonate (PC) and cycloolefins (COP), preferably polycarbonate (PC). Preferably, each light guide 5 is formed from polycarbonate (PC).

[0109] The light guide 5 may comprise a conduit, in particular in the form of a tube. Preferably, the light guide 5 is solid.

[0110] According to one variant, the light guide 5 comprises at least one optical fiber. Advantageously, the light guide 5 is formed by at least one optical fiber.

[0111] In the example illustrated in Figure 1, a guide assembly 10 comprises a trunk 11 from which several branches extend in the form of tubing, each branch forming a light guide 5. Such a guide assembly 10 has a fork shape. Thus, the light source 9 supplies the guide assembly 10 with a single light input of the trunk 11.

[0112] Preferably, the guide assembly 10 is formed from the same material, for example entirely in one piece.

[0113] The light guide 5 may also have a planar shape, for example a sheet as described below with reference to FIG. 3.

[0114] The light guide 5 is for example formed from a material chosen from the group comprising polymethyl methacrylate (PMMA), polycarbonate (PC) and cycloolefins (COP), preferably polycarbonate (PC). In this example, the guide assembly 10 is formed from polycarbonate (PC).

[0115] As shown for example in Figure 2, the air purification device 1 preferably also comprises means 13 for holding the cotton pad 3 in position. The means 13 for holding the pad in position are preferably formed by a cartridge.

[0116] The photocatalyst consists of at least one photocatalyst material. In this example, the photocatalyst is formed solely of at least one photocatalytic catalyst material. Thus, the photocatalyst fibers are formed solely of photocatalyst.

[0117] Furthermore, the photocatalyst is a photocatalytic catalyst, which is not metallic. Thus, the photocatalyst fibers are not metallic. Advantageously, the photocatalyst is made only of photocatalyst material. These can be identical or different photocatalysts. In other words, it can be a single photocatalyst material or different photocatalyst materials.

[0118] Advantageously, the photocatalyst fibers exclude any material other than the photocatalyst, with the exception of materials inherent in the manufacturing process of the photocatalyst.

[0119] Advantageously, the photocatalyst fibers comprise the photocatalyst in their mass.

[0120] Advantageously, the wadding pad 3 is made of photocatalyst fibers. These may be identical or different photocatalyst fibers.

[0121] Advantageously, the wadding cushion 3 is formed solely of photocatalyst fibers.

[0122] Advantageously, the wadding cushion 3 formed from photocatalyst fibers is not a cushion coated with photocatalyst but a cushion made from photocatalyst fibers.

[0123] The photocatalyst fibers are preferably obtained by a continuous preparation process where a photocatalyst dispersion is extruded and solidified. Preferably, the photocatalyst dispersion is an aqueous dispersion of at least one vinyl alcohol polymer. Advantageously, the extrusion of the photocatalyst dispersion is carried out continuously and unidirectionally in a bath capable of causing the fiber to solidify. Washing and drying steps may be envisaged.

[0124] Preferably, the photocatalyst fibers have a smallest dimension of at least 10 micrometers. Thus, the photocatalyst fibers are macroscopic. In other words, a macroscopic fiber is understood to mean a strand in which the smallest dimension is at least 10 micrometers. Preferably, the strand has two average dimensions orthogonal to its longitudinal axis, the first average dimension (corresponding to its width) varying from 30 to 60 micrometers, preferably from 40 to 50 micrometers, and the second average dimension (corresponding to its thickness) varying from 10 to 40 micrometers, preferably from 10 to 20 micrometers.

[0125] The photocatalyst is preferably a semiconductor material. In this example, the photocatalyst comprises at least one oxide selected from the group consisting of TiO2, ZnO, CeO2.

[0126] Advantageously, the photocatalyst comprises at least partially crystalline TiO2, preferably predominantly crystalline TiO2. Preferably, the photocatalyst is at least partially crystalline TiO2, preferably predominantly crystalline TiO2.

[0127] The photocatalyst is activated by light which may be of the ultraviolet type, via the light guide(s) 5 configured to guide the light inside the wadding cushion 3.

[0128] A simple cutting of the cotton pad 3 to the dimensions of the air purification device 1 or the means for holding in position 13 makes it possible to produce purification devices of any size.

[0129] For example, the lateral light diffusion means 8 are formed by surface alterations of the light guide 5. The surface alterations of each light guide 5 can be carried out in various ways, and in particular by sandblasting, chemical etching or fusion processes using high-intensity light radiation such as a laser. Of course, such alterations can also be carried out by many other mechanical or chemical processes.

[0130] The surface alterations of each light guide 5 may be distributed symmetrically or asymmetrically (for example progressively). Indeed, in order to achieve homogeneous illumination of the cotton pad 3, and therefore homogeneous activation of the photocatalyst in the cotton pad 3, the surface density or the dimension of the alterations may vary from one zone to another of the light guide 5.

[0131] For example, the surface density of alterations is low on the side of light source 9 and increases away from light source 9.

[0132] The light source 9 is preferably single. Alternatively, the light source 9 may be composed of several identical or different light sources, which may be of different natures, and in particular be in the form of light-emitting diodes (LEDs) or extended sources such as incandescent lamps, fluorescent tubes or discharge tubes incorporating a gas such as neon.

[0133] In this example, the light source 9 supplies light to one end of each light guide 5. In this example, the light source 9 is a UV light source, and comprises an LED. For example, the light source 9 can be made with a UVA, UVB or UVC LED.

[0134] Alternatively or in a complementary manner, the light source 9 may comprise a collector capable of focusing natural solar light in a point or linear manner towards at least one end of at least one light guide 5.

[0135] Figure 3 represents an alternative embodiment of the air purification device 1. In this alternative, the air purification device 1 is such that the wadding cushion 3 is formed in its thickness by two half-wadding cushions 14, between which at least one light guide 5 is received. Thus, according to the alternative shown in Figure 3, a light guide 5 is received between two half-wadding cushions 14.

[0136] According to this embodiment variant, it may be particularly advantageous for the light guide 5 to take the form of a sheet. For example, the light guide 5 may comprise a sheet formed from optical fibers, in particular optical fibers woven together. In addition to a light guide 5 passing through the wadding pad 3, an additional light guide 5 may also be provided, for example in the form of a sheet, in particular formed from optical fibers, against the upper surface of the wadding pad 3 and / or against the lower surface of the wadding pad 3. Thus, for example, a first of the light guides 5 passes through the wadding pad 3, a second of the light guides 5 is arranged against an external surface of the wadding pad 3, and a third of the light guides 5 is arranged against another surface of the wadding pad 3 opposite the external surface.

[0137] According to a variant, the wadding cushion 3 can be obtained from a textile sheet comprising fibers formed from photocatalyst, preferably by fluffing. Advantageously, the textile sheet comprises the light guide 5, the light guide 5 preferably comprising at least one optical fiber.

[0138] Figure 4 represents a first exemplary embodiment of an air treatment device 15. Such an air treatment device 15 comprises an air purification device 1 as previously described, a light source 9 as previously described, and an air circulation duct 17 between an air inlet 19 and an air outlet 21.

[0139] Alternatively, the air treatment device 15 comprises several air outlets, identical or different, and the air treatment device 15 comprises several air inlets, identical or different.

[0140] The air purification device 1 is arranged in the air circulation duct 17. Each light guide 5 is supplied with light there by the light source 9.

[0141] In this example, the air treatment device 15 is a domestic appliance comprising a casing 23 forming the outer casing of the air treatment device 15.

[0142] Preferably, the air treatment apparatus 15 is configured to be movable during operation. Thus, the air treatment apparatus 15 is an individual domestic appliance and not a centralized air conditioning system, for example of a hospital, an airport, a shopping center, a subway or train station.

[0143] Furthermore, the air treatment device 15 is preferably an individual portable device suitable for small spaces such as that of an individual dwelling or a caravan. Thus, the air treatment device 15 has a volume of less than 1 m 3 , preferably less than 0.8 m 3 , more preferably less than 0.6 m 3 .

[0144] Furthermore, the air treatment device has a mass less than or equal to 30 kg, preferably less than 20 kg, more preferably less than 6 kg.

[0145] The air treatment apparatus 15 further comprises an air movement member 25. The air movement member 25 is configured to move air from the air inlet 19 to the air outlet 21. The air movement member 25 is for example a radial flow or mixed flow turbine, or a fan, arranged downstream of the air purification device 1. In this case, as shown in FIG. 3, a motor-fan unit 26 may be arranged on the side of the air outlet 21, above the air purification device 1.

[0146] In the example shown in Figure 4 and Figure 5, the air purification device 1 comprises several cotton pads 3 arranged one above the other, with or without contact. As previously described, each cotton pad 3 receives at least one light guide 5, and each cotton pad 3 is formed of photocatalyst fibers.

[0147] In this example, the cotton pads 3 are spaced apart by at least a predetermined value such that air to be purified circulates between the cotton pads 3. Preferably, the predetermined value is greater than or equal to 1 millimeter, more preferably greater than or equal to 5 millimeters. Alternatively, the cotton pads 3 are directly superimposed on each other. In this example, the cotton pads 3 are arranged in parallel layers. The parallel layers may be flat or non-flat. Thus, the cotton pads 3 are not necessarily flat and may be curved.

[0148] Alternatively, other arrangements of the wadding pad(s) may be envisaged, for example in the form of rolls where each wadding pad is rolled up on itself in the manner of a roll of carpet.

[0149] Furthermore, in this example, each wadding cushion 3 is arranged parallel to the air flow in the air circulation duct 17. Alternatively, each wadding cushion is arranged transversely to the air flow in the air circulation duct.

[0150] In this example, the air treatment device 15 has an apparent surface area of ​​cotton wool cushion 3 of at least 4000 cm 2 , preferably at least 6000 cm 2 , more preferably at least 8000 cm 2 .

[0151] For example, the air flow moving in the air purification device 1 has a speed of less than 1 m / s, preferably less than 0.5 m / s, more preferably less than 0.2 m / s. Thus, a contact time of the pollutants with the cotton pad 3 is at least 0.5 s.

[0152] The air treatment apparatus 15 further comprises a volatile organic compound analyzer 27 and an automatic adjustment member 29. The automatic adjustment member 29 is configured to automatically adjust, as a function of the volatile organic compound content analyzed by the analyzer 27, the speed of the air entering the air inlet 19 and / or the light intensity of the light source 9.

[0153] Preferably, as shown in Figure 5, the air treatment device 15 further comprises at least one filter 31. The filter 31 is arranged, depending on the movement of the air between the air inlet 19 and the air outlet 21, upstream or downstream of the air purification device 1. For example, a filter 31 can be placed upstream of the air purification device 1. In this case, it is possible in particular to provide a particle filter, of the HEPA filter type.

[0154] Advantageously, at least one filter, such as an activated carbon filter or a formaldehyde filter, is arranged downstream of the air purification device 1.

[0155] Alternatively or additionally, the air treatment device 15 further comprises a dehumidifier.

[0156] For example, as shown in Figure 6, the air treatment apparatus 15 further comprises one or more fans 31, agitators or tabulators. Thus, the air circulation is carried out according to a low average flow rate but swirling between the cotton pads 3. Optionally, the air treatment apparatus 15 also comprises at least one deflector 33, configured to reduce air turbulence before the air outlet 21.

Claims

CLAIMS 1. Air purification device (1), characterized in that it comprises a cotton pad (3) receiving at least one light guide (5), the cotton pad (3) being formed from photocatalyst fibers, the light guide (5) being configured to be supplied with light by a light source (9), and the light guide (5) having lateral light diffusion means (8) in order to diffuse light laterally relative to the direction of movement of the light in the light guide (5).

2. Air purification device (1) according to claim 1, wherein the cotton pad (3) receives several light guides (5).

3. Air purification device (1) according to claim 2, wherein a first of the light guides (5) passes through the cotton pad (3), a second of the light guides (5) is arranged against an external surface of the cotton pad (3), and preferably a third of the light guides (5) is arranged against another surface of the cotton pad (3) opposite the external surface.

4. Air purification device (1) according to any one of claims 1 to 3, wherein the light guide (5) comprises at least one optical fiber.

5. Air purification device (1) according to any one of claims 1 to 4, which further comprises means for holding in position (13) the cotton pad (3), the means for holding in position (13) preferably being formed by a cartridge.

6. Air purification device (1) according to any one of claims 1 to 5, wherein the photocatalyst fibers have a smallest dimension of at least 10 micrometers.

7. Air purification device (1) according to any one of claims 1 to 6, wherein the photocatalyst is a semiconductor material.

8. Air purification device (1) according to any one of claims 1 to 7, wherein the photocatalyst comprises at least one oxide chosen from the group consisting of TiCh, ZnO, CeCh.

9. Air purification device (1) according to any one of claims 1 to 8, wherein the photocatalyst comprises at least partially crystalline TiCh, preferably predominantly crystalline TiCh.

10. Air purification device (1) according to any one of claims 1 to 9, which comprises several wadding cushions (3) arranged one above the other, each wadding cushion (3) receiving at least one light guide (5), each wadding cushion (3) being formed of photocatalyst fibers.

11. Air purification device (1) according to claim 10, wherein the cotton pads (3) are spaced apart by at least a predetermined value such that air to be purified circulates between the cotton pads (3), preferably the predetermined value being greater than or equal to 1 millimeter, more preferably greater than or equal to 5 millimeters.

12. Air purification device (1) according to claim 10, wherein the cotton pads (3) are directly superimposed on each other.

13. Air treatment apparatus (15) comprising: - an air circulation duct (17) between an air inlet (19) and an air outlet (21), - a light source (9), and - an air purification device (1) according to any one of claims 1 to 12 arranged in the air duct (17), in which the light guide (5) is supplied with light by the light source (9).

14. Air treatment apparatus (15) according to claim 13, which is a domestic appliance comprising a casing (23) forming the outer casing of the air treatment apparatus (15).

15. Air treatment apparatus (15) according to any one of claims 13 to 14, wherein the light source (9) is a UV light source.

16. Air treatment apparatus (15) according to any one of claims 13 to 15, wherein the light source (9) comprises an LED.

17. Air treatment apparatus (15) according to any one of claims 13 to 16, which further comprises: - an analyzer (27) of volatile organic compounds and - an automatic adjustment member (29), which is configured to automatically adjust, depending on the content of volatile organic compounds analyzed by the analyzer (27), the speed of the air entering the air inlet (19) and / or the light intensity of the light source (9).

18. Air treatment apparatus (15) according to any one of claims 13 to 17, wherein each cotton pad (3) is arranged parallel to the air flow in the air circulation duct (17).

19. Air treatment apparatus (15) according to any one of claims 13 to 17, wherein each wadding cushion (3) is arranged transversely to the air flow in the air circulation duct (17).

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