Air purification device

Abstract

This invention relates to an air purification device, comprising at least: an air inlet; an air outlet; an air filter device integrating at least one optical fiber and a catalyst having photocatalytic activity, the optical fiber having variations on its surface to diffuse light laterally relative to the direction of light movement in the optical fiber; and a photon source.

Description

Technical Field

[0001] This invention relates to the field of indoor air decontamination and purification in residences, and more particularly to an air purification device comprising an air filter integrating at least one optical fiber and a catalyst with photocatalytic activity.

[0002] It should be noted that in this document, the terms “longitudinal,” “lateral,” “vertical,” “parallel,” “rotation,” “horizontal,” “vertical,” “lower,” “upper,” “high,” “lower,” “secant,” “coaxial,” “convex,” “concave,” and “plane” used to describe the device according to the invention refer to the device when it is placed on a horizontal surface during use.

[0003] Pollutants are mainly composed of two categories. One category includes particulate pollutants, such as dust, bacteria, and mold, which are large and have complex molecular structures, ranging in size from 0.01 micrometers to several hundred micrometers. The other category includes gaseous pollutants, such as volatile fumes (like odors) perceived by the olfactory organs, or volatile organic compounds (VOCs), which are compounds that typically have simple chemical structures. Gaseous pollutants can be composed of a variety of chemical elements. They are very small, ranging from a few angstroms to a few nanometers in size.

[0004] Advanced oxidation technologies (AOT) allow the oxidation of volatile organic compounds (VOCs). The most effective are those that result in the formation of hydroxyl radicals (OH·), which have a stronger oxidizing power than conventional oxidants. Photocatalysis is one such example. Photocatalysis involves irradiating a semiconductor material (TiO2 type), which allows the oxidation or reduction of VOCs in contact with the photocatalytic material. The energy carried by the light allows the semiconductor to be activated. The semiconductor is considered a catalyst. The principle is based on the absorption of photons by a solid semiconductor, which causes electrons to be lifted from the valence band to the conduction band by releasing holes, thereby forming radicals. These radicals either react with compounds present in the surrounding medium or recombine according to various mechanisms, thus endowing the solid with oxidizing and reducing properties. Through this technology, most volatile organic compounds, as well as many pesticides, herbicides, surfactants, and colorants, are completely oxidized to less toxic products, ultimately yielding carbon dioxide (CO2) and water (H2O).

[0005] The main VOCs in ambient air are: formaldehyde, acetaldehyde, acetone, heptane, alcohols including isopropanol, decane, benzene, and toluene. Background Technology

[0006] Air purification devices using photocatalytic technology are known. However, instead of eliminating VOCs and purifying the air, these devices often emit VOCs. It is difficult to understand why dust collectors or purifiers emit VOCs, even if the nature and / or quantity of these emitted VOCs differs from those in the air before initial filtration. Therefore, the biggest drawback of these devices is the generation of byproducts, which can sometimes be more dangerous than the original molecules (e.g., heptane, which degrades to form formaldehyde).

[0007] To reduce the formation of these toxic byproducts, known air purifiers employ reduced operating conditions (gas velocity or light intensity) until the VOC content in the air to be purified drops below a certain level. However, it's unfortunate that the purifier cannot be operated precisely when most needed, i.e., when high concentrations of VOCs are present. As a result, gaseous pollutants cannot be effectively absorbed and removed. Furthermore, the accumulation of pollutants as particles on the surface of the gas elimination filter can lead to other problems, such as providing an incubation period for bacterial growth or a loss of filtration efficiency over time.

[0008] This invention proposes to overcome these drawbacks by providing an air purification device comprising an air filter that integrates at least one optical fiber and a catalyst having a photocatalytic effect that can eliminate pollutants. Summary of the Invention

[0009] This invention relates to an air purification device, the air purification device comprising at least

[0010] - One air intake;

[0011] -A vent;

[0012] - An air filtration device integrating at least one optical fiber and a catalyst with photocatalytic activity, wherein the optical fiber has a surface variation to diffuse light laterally relative to the direction of light movement in the optical fiber.

[0013] - A photon source.

[0014] Preferably, the device according to the invention is a household device including a housing, the housing forming the outer casing of the device.

[0015] One advantage of the present invention is that it provides a compact device for purifying air by photocatalysis. Preferably, the device according to the invention is movable during its use, that is, the device is mobile and not fixed to a support. Therefore, the user can move the device by pushing it from its base or by grasping it by hand, whether the device is in operation or not.

[0016] The device according to the invention is a stand-alone household device, rather than a centralized air conditioning system such as in a hospital, airport, shopping mall, subway, or train station.

[0017] The device according to the invention is a stand-alone portable device suitable for small spaces, such as the space of a detached house or a travel trailer.

[0018] The device according to the invention includes at least one air inlet. The device according to the invention is designed to include several identical or different air inlets.

[0019] The device according to the invention includes at least one air outlet. The device according to the invention is designed to include several identical or different air outlets. Attached Figure Description

[0020] The objects, aspects, and advantages of the invention will be better understood from the description of specific embodiments of the invention presented by way of the following non-limiting examples, in which:

[0021] Figure 1 This is a perspective view of an embodiment of an air filtration device, which integrates at least one optical fiber and a catalyst with photocatalytic activity. The device consists of multiple fabric sheets stacked in thin sheets.

[0022] Figure 2 This is a perspective view of a first embodiment of the device according to the present invention.

[0023] Figure 3 This is a schematic diagram illustrating the air circulation principle in a purifier. Air enters through inlet A and exits through outlet B. A particulate filter is present in section 1, and an air filtration device integrating at least one optical fiber and a photocatalyst according to the present invention is present in section 2.

[0024] Figure 4 This is a schematic diagram illustrating the air circulation principle within the air filtration device of an air purifier. Air circulates tangentially within the filter device 2 at a certain rotational speed relative to the device's position. This rotational speed can be generated by a fan, agitator, or turbulence generator positioned below the filter device. Detailed Implementation

[0025] The device according to the invention comprises an air filtration device integrating at least one optical fiber and a photocatalytic catalyst. Preferably, the photocatalytic catalyst is disposed on the surface of the optical fiber, that is, the fiber is coated with a photocatalytic catalyst.

[0026] The filtering device of the apparatus according to the invention is preferably a fabric sheet comprising optical fibers woven with warp and weft yarns and arranged as warp and / or weft, the optical fibers being capable of lateral light emission. The adhesive yarns of the fabric sheet advantageously have photocatalytic particles on their surface.

[0027] Preferably, the filtration device of the apparatus according to the invention comprises at least one fabric sheet including optical fibers woven with adhesive threads coated with a catalyst having photocatalytic activity.

[0028] The filter element of the device according to the invention is designed with multiple fabric sheets stacked together to form a continuous stacked layer. The sheets are advantageously arranged in parallel layers. The sheets are preferably spaced at least 1 cm apart. The air to be filtered flows between the fabric sheets to contact the catalyst. Advantageously, the airflow is at a low to medium flow rate but in a vortex manner. These sheets allow the air to flow tangentially relative to the filter element, rather than laterally (not through the element), that is, parallel to the element rather than perpendicular to it; the air flows parallel to the fabric sheets, along the sheets and / or between the sheets, which allows for maximum contact between the air to be filtered and the active cleaning surface; if the fabric sheets are too far apart, the air flows only in a laminar manner, and the contact time with the filter element is reduced, resulting in decreased cleaning efficiency.

[0029] Advantageously, the fabric sheets are positioned close enough to maximize contact between the air and the photocatalytic surface, and to induce vortices in the airflow. Advantageously, one or more additional fans (in addition to the main motor fan assembly of the device), agitators, or turbulence generators, such as stationary propellers, are designed at or below the inlet of the filter device to generate vortices between the fabric sheets.

[0030] One can imagine the fabric sheet or other arrangements of these fabric sheets, such as in the form of rolls, where the sheets are rolled up on themselves in the manner of a carpet roll.

[0031] The optical fiber has a variation on its surface, and the free end of the optical fiber can be arranged to face the light source so that light can propagate at the variation and emit light laterally to activate the photocatalytic particles.

[0032] In other words, photocatalytic particles are activated by radiation, which can be of the ultraviolet type, using optical fibers capable of uniformly guiding light within the fabric sheet. Due to the weaving of the optical fibers and adhesive threads, the resulting fabric sheet is therefore uniform and easily manipulated for placement in a device or fixed in a frame. Simply cutting the fabric sheet to the dimensions of the device or frame allows for the creation of decontamination devices of various sizes.

[0033] Furthermore, the presence of the adhesive threads allows for the formation of a filter device whose filtration accuracy is directly related to the weave of the fabric sheet including the adhesive threads, and not just the number of optical fibers used. In effect, the air to be filtered can flow within the sheet while blocking the passage of, for example, large particles.

[0034] Furthermore, the surface of optical fibers can be modified in various ways to emit light laterally, particularly through processes such as sandblasting, chemical etching, or melting using high-intensity light radiation, such as lasers. Clearly, such modifications can also be achieved through many other mechanical or chemical methods.

[0035] Advantageously, the variations in the optical fibers can be distributed symmetrically or asymmetrically (gradually) on the surface of the fabric sheet. In practice, to achieve uniform illumination of the fabric sheet and thus uniform activation of the photocatalytic particles across the entire surface of the fabric, the surface density, or the size of the variations, can vary between one region of the fabric sheet and another. Typically, the surface density of the variations is low near the light source and increases with distance from the light source.

[0036] The photocatalyst in the air filtration device of the device according to the present invention is preferably a semiconductor material.

[0037] Preferably, the catalyst with photocatalytic activity includes at least one oxide selected from the oxide combination TiO2, ZnO, and CeO2.

[0038] Preferably, the catalyst with photocatalytic activity comprises at least partially crystalline titanium oxide.

[0039] The device according to the invention includes a photon source. It should be noted that the photon source may consist of several identical or different photon sources.

[0040] The photon source is preferably one or more identical or different light sources. The light source used to illuminate the free end of the optical fiber can have different properties, and in particular can be in the form of a light-emitting diode, or can be in the form of an extended light source such as an incandescent lamp, a fluorescent tube, or a discharge tube mixed with a gas such as neon.

[0041] The device according to the invention preferably includes a light source, which is a lighting system including LEDs, preferably UV.

[0042] The light source can be made of UVA, UVB, or UVC LEDs. Such a system allows for a combination of minimal energy consumption and significant efficiency. Furthermore, this type of lighting system permits highly specialized designs that optimize the illumination of the catalyst.

[0043] Therefore, the present invention also relates to an air filtration device comprising an air filtration unit that integrates at least one photocatalytic catalyst with a UV-transmitting illumination system for the catalyst, the illumination system comprising an LED, preferably a UV-transmitting LED.

[0044] Furthermore, according to a particular embodiment, the light source may include a collector capable of concentrating natural sunlight in a point or line manner along at least one free end of the optical fiber.

[0045] In addition, photocatalytic particles can be added to different components of the fabric sheet in different ways.

[0046] According to the first variation, a coating containing photocatalytic particles can be applied to the bonding lines, and then these lines are braided with optical fibers. In this case, the optical fiber lacks photocatalytic particles and only allows light to travel along the bonding lines on which the photocatalytic particles are carried.

[0047] According to a second variation, a coating containing photocatalytic particles can be applied to a fabric formed from optical fibers associated with an adhesive thread. In this case, the photocatalytic particles are embedded in the coating of the coated fabric sheet, making it permeable to the gas or liquid to be decontaminated. The coating can be deposited in various ways, particularly by immersion, padding, emulsion, spraying, printing, encapsulation, and electrodeposition.

[0048] In this configuration, the optical fiber can be locally braided together with the bonding thread, with the fiber essentially positioned in a plane parallel to the plane defined by the bonding thread, on which a coating is applied. Therefore, the coating is not applied to the optical fiber itself, but only to one of the surfaces of the sheet formed by the bonding thread. This bonding thread-over-coating allows for a protective shielding of the optical fiber located in a misaligned parallel plane. In practice, the bonding thread can be braided according to a canvas-type weave. This type of weave actually provides the fabric sheet with optimal mechanical strength and surface uniformity.

[0049] Typically, optical fibers have a core. Or Heart It is surrounded and covered by a protective shell. Depending on the circumstances, the above modifications may damage different layers, up to the core or heart. It should be noted that in some cases, changing the protective layer, depending on the material, is sufficient to achieve a change that allows for lateral light diffusion; in other cases, both the protective layer and the shell must be changed.

[0050] According to the first embodiment, the optical fiber may have a core formed from a material selected from the group consisting of polymethyl methacrylate (PMMA), polycarbonate (PC), and cycloolefin (COP).

[0051] In this case, the optical fiber is made of two materials and has a core covered with a sheath, which can have different properties.

[0052] According to a second embodiment, the optical fiber can be formed of a material selected from the group consisting of glass, quartz, and silica. In this case, a sheath can cover the optical fiber to protect it or to transfer photocatalytic particles onto a fabric sheet.

[0053] Advantageously, the adhesive line can be formed of a material selected from the group consisting of polyamide, polyester, polyethylene and polypropylene.

[0054] The device according to the invention may further include a time delay device and / or a volatile organic compound analyzer and / or a device for automatically adjusting the velocity of the gas passing through it and / or a device for adjusting the intensity of ultraviolet irradiation, said adjustment being performed based on a time determined by the time delay device or based on the content of volatile organic compounds analyzed by the analyzer.

[0055] The device according to the invention may further include a volatile organic compound analyzer, and equipment for automatically adjusting the rate of airflow and / or adjusting the intensity of the photon source based on the content of volatile organic compounds analyzed by the analyzer.

[0056] The air purification device according to the invention may further include one or more identical or different pre-filters upstream of the flow path to capture dust and particles. Typically, the air to be purified is forced or drawn into the filter by a radial flow or mixed flow turbine (or fan) arranged downstream of the filter. In this case, an electric motor fan assembly can be positioned above the filter on the outlet side.

[0057] The pre-filter may be a particulate filter, which separates particles with a diameter larger than the filter pore diameter by mechanical action by retaining them on the surface, and may retain particles with a diameter smaller than the filter pore diameter under the action of electrostatic force. In this case, the device according to the invention further includes a particulate filter.

[0058] The pre-filter can be a dehumidifier to reduce moisture content and improve efficiency.

[0059] The pre-filter can be an activated carbon filter. These filters are designed to respond to industrial emissions of volatile organic compounds (VOCs). In an activated carbon adsorption system, contaminated air is directed to a carbon bed. The carbon extracts VOCs from the air and adsorbs them by holding them on a surface. In this case, the device according to the invention also includes an activated carbon filter.

[0060] The pre-filter can be a HEPA (High Efficiency Particulate Air) type filter, which means a high-efficiency particulate air filter. The air filter is preferably a device capable of filtering at least 99.97% of particles with a diameter greater than or equal to 0.3 μm in a single pass.

[0061] For situations where geometric constraints force VOCs to still appear downstream of the photocatalytic catalyst, the air purification device according to the present invention may further include one or more identical or different filters.

[0062] In these variations, it is possible to place another medium, called a scavenger, downstream of the airflow path. Its function is to at least partially retain VOCs after a chemical reaction, if necessary. Therefore, distinctions are made between different categories of scavengers:

[0063] - VOC substances such as formaldehyde or acetaldehyde are retained through simple physical interactions, such as activated carbon or certain zeolites.

[0064] - Substances that chemically interact with VOCs such as formaldehyde or acetaldehyde and cause carbon molecules generated from the reaction of VOCs such as formaldehyde or acetaldehyde with the trapping medium to escape: This is the case where chemical filters contain permanganate salts such as potassium permanganate.

[0065] - Substances that chemically interact with VOCs such as formaldehyde or acetaldehyde without releasing carbon molecules generated from the reaction of VOCs such as formaldehyde or acetaldehyde with the trapping medium: This is the case where the trapping medium contains compounds containing NH groups; the chemical reaction here is more accurately described as a grafting type, because the reaction between the NH group (the substance on the trapping medium) and the C=O group of formaldehyde or acetaldehyde results in the formation of an NC-OH type sequence, without the formation of volatile carbon molecules.

[0066] In this case, the device according to the invention also includes a formaldehyde filter.

[0067] Therefore, the term "capture" refers to the retention of formaldehyde or acetaldehyde, either by a capture medium or through a chemical reaction (e.g., grafting) or by physical interactions of the adsorption or absorption type.

[0068] To improve the efficiency of the device according to the invention, the collection medium can also be placed upstream of or parallel to the photocatalyst when the device is operated in a recirculating manner, that is, when the air of the space to be purified is circulated in a loop (open or semi-open loop).

[0069] In this operating mode, the VOC capture medium can also be used as a dust filter.

[0070] Advantageously, the device according to the invention is small in size and has a volume of less than 1m. 3 Preferably less than 0.8m 3 More preferably less than 0.6m 3 The volume.

[0071] Advantageously, the device according to the invention is lightweight, with a mass not exceeding 30 kg, preferably less than 20 kg, and more preferably less than 12 kg.

[0072] Advantageously, the device according to the invention has a length of at least 4000 cm. 2 Preferably at least 6000cm 2 More preferably at least 8000cm 2 The apparent surface of a fabric sheet. The apparent surface refers to the area of ​​the fabric sheet in contact with airflow.

[0073] Advantageously, the device according to the invention has an airflow velocity of less than 1 m / s, preferably less than 0.5 m / s, and more preferably less than 0.2 m / s in the fabric sheet.

[0074] Advantageously, the device according to the invention has a contact time between the contaminant and the fabric sheet of at least 0.5 s, and this contact time can be extended as much as possible, due to the vortex of the airflow to be treated. Therefore, the airflow to be treated has a rotational speed at all points. The vortex increases the average contact time between the air to be filtered and the filtering device (such as the fabric sheet). The longer the contact time, the lower the risk of generating contaminant byproducts.

Claims

1. An air purification device, characterized in that, Including at least: - One air intake; -A vent; - An air filtration device integrating at least one optical fiber and a catalyst with photocatalytic activity, wherein the optical fiber has a surface variation to diffuse light laterally relative to the direction of light movement in the optical fiber. -Photon source, Furthermore, the air purification device is a movable device during its use. The air filtration device is designed with multiple fabric sheets stacked in a continuous stacked layer, arranged in parallel layers so that the air to be filtered flows between the fabric sheets to contact the catalyst. The sheets allow the air to flow tangentially relative to the filtration device rather than laterally. The fabric sheets are close enough to maximize the contact between the air and the surface of the catalyst and to induce vortices in the airflow. These vortices increase the average contact time between the air to be filtered and the fabric sheets and reduce the risk of generating contaminating byproducts.

2. The air purification device according to claim 1, characterized in that, The air purification device is a household appliance that includes a housing, which forms the outer shell of the household appliance.

3. The air purification device according to claim 1 or 2, characterized in that, The filter device is at least one fabric sheet, the fabric sheet including optical fibers woven with adhesive threads, the adhesive threads being coated with a catalyst having photocatalytic activity.

4. The air purification device according to claim 1 or 2, characterized in that, Catalysts with photocatalytic activity are semiconductor materials.

5. The air purification device according to claim 1 or 2, characterized in that, Catalysts with photocatalytic activity include at least one oxide selected from the oxide combination TiO2, ZnO, and CeO2.

6. The air purification device according to claim 1 or 2, characterized in that, Catalysts with photocatalytic activity include at least partially crystalline titanium dioxide.

7. The air purification device according to claim 1 or 2, characterized in that, The photon source is one or more light sources.

8. The air purification device according to claim 1 or 2, characterized in that, The photon source is one or more light sources, and the light source is a lighting system including LEDs.

9. The air purification device according to claim 1 or 2, characterized in that, The photon source is one or more light sources, and the light source is an illumination system including UV.

10. The air purification device according to claim 1 or 2, characterized in that, The air purification equipment includes a volatile organic compound (VOC) analyzer and equipment for automatically adjusting the velocity of the air entering it and / or adjusting the intensity of the photon source based on the VOC content analyzed by the analyzer.

11. The air purification device according to claim 1 or 2, characterized in that, The air purification equipment also includes a particulate filter.

12. The air purification device according to claim 1 or 2, characterized in that, The air purification equipment also includes an activated carbon filter.

13. The air purification device according to claim 1 or 2, characterized in that, The air purification equipment also includes a formaldehyde filter.

14. The air purification device according to claim 1 or 2, characterized in that, The air purification device also includes one or more fans, agitators, or turbulence generators.

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