Photocatalytic air purification element

Abstract

An air purification element (1) is described, the air purification element (1) comprising a printed circuit board (2) and a plurality of light sources (3) applied and electrically connected to said printed circuit board (2). The air purification element (1) further comprises a photocatalytic coating (4) applied in direct contact at least on the plurality of light sources (3).

Description

[0001] DESCRIPTION

[0002] PHOTOCATALYTIC AIR PURIFICATION ELEMENT

[0003] The present invention relates to the technical field of air purification devices.

[0004] In particular, the present invention relates to a photocatalytic air purification element capable of promoting the degradation of chemical molecules that are pollutants and / or harmful to human health.

[0005] In the indoor environments of buildings, an undesirable accumulation of substances potentially harmful to human health can occur over time.

[0006] In this context, a known solution is to install devices configured to promote a recirculation of air in the indoor environments in order to promote a continual removal of such harmful substances, thereby improving the overall quality of the air breathed by people who pass through or stay in such rooms.

[0007] However, the known recirculation systems are also affected by problems that render their operation and performance unsatisfactory on the whole.

[0008] In fact, in the air that is drawn, usually from outside environments, to replace the foul air, polluting compounds such as nitrogen oxides (NO, NOx, NO2) and volatile organic compounds (VOCs) can also be present.

[0009] The use of photocatalytic devices which implement catalysts activatable by light radiation to eliminate these compounds is known.

[0010] Following such activation, free radicals known as “Reactive Oxygen Species” (abbreviated “ROS”) are generated; they react chemically with the polluting compounds, oxidising them progressively until transforming them into CO2 and H2O at the end of the process.

[0011] However, such photocatalytic devices have limited and / or unsatisfactory levels of efficiency, mainly due to their structure and composition, which is able to neutralise / reduce / oxidise only a limited portion of the abovementioned polluting compounds.

[0012] Furthermore, the activation of the catalysis process requires the use and implementation of light sources that must be suitably positioned in order to be able to correctly irradiate the catalyst, resulting in structures that are generally complex and / or costly, in which the photocatalyst is not placed in the right correlation with the light source, the result being that the efficiency thereof is strongly influenced by the correct irradiation of the photocatalyst, given that even in situations of correct illumination of the latter, it is noted that the photocatalytic efficiency is tied, specifically inversely proportional, to the square of the distance between catalyst and light source.

[0013] In this context, the technical task at the basis of the present invention is to propose a photocatalytic air purification element that overcomes at least some of the abovementioned drawbacks of the prior art.

[0014] In particular, it is an object of the present invention to provide a photocatalytic air purification element characterised by a structure that is simple but at the same time has high performances.

[0015] The stated technical task and the specified objects are substantially achieved by a photocatalytic air purification element comprising the technical features disclosed in one or more of the appended claims.

[0016] According to the present invention, a photocatalytic air purification element is shown.

[0017] This element can be advantageously implemented for the neutralisation / degradation of harmful volatile chemical compounds.

[0018] The air purification element comprises a printed circuit board, a plurality of light sources and a photocatalytic coating.

[0019] The light sources are applied and electrically connected to the printed circuit board, i.e. they are mounted on the printed circuit board. The photocatalytic coating is applied in direct contact at least on the plurality of light sources.

[0020] In one embodiment, the air purification element further comprises a ductlike support adapted to enclose a finite volume.

[0021] The duct-like support defines an internal volume along which air can flow, passing over the photocatalytic coating.

[0022] In this context the printed circuit board is internally coupled to the duct-like support so as to define an inner wall thereof facing the internal volume.

[0023] In one embodiment, the duct-like support is of the tubular type and has a cross section that is for example circular and / or square.

[0024] Advantageously, the air purification element proposed here makes it possible to maximise the efficiency of neutralisation of the undesirable chemical compounds, since the distance between the light sources and the photocatalytic coating is considerably reduced (possibly to zero), thus ensuring that the geometry of the air purification element favours the maximisation of absorption, on the photocatalyst, of the light photons emitted by the light source for the activation of the catalytic process.

[0025] Furthermore, the structure of the air purification element allows the entire surface of the photocatalytic coating to be exposed to the flow of air to be purified, which can flow freely over the photocatalytic coating, since the light sources do not obstruct the passage thereof, being incorporated beneath the coating itself.

[0026] The dependent claims, incorporated herein by reference, correspond to different embodiments of the invention.

[0027] Additional features and advantages of the present invention will emerge more clearly from the approximate and thus non-limiting description of a preferred but not exclusive embodiment of a photocatalytic air purification element, as illustrated in the appended drawings in which:

[0028] - figure 1 shows a light source of the LED type, implementable in the present invention;

[0029] - figure 2 shows, in detail, one of the components of the air purification element described herein;

[0030] - figure 3 shows a cross section of the air purification element;

[0031] - figure 4 shows a possible embodiment of the invention.

[0032] In the appended figures, the reference number 1 generically denotes a photocatalytic air purification element, which will be identified below in the present description simply as the element 1 .

[0033] The air purification element 1 proposed here may be used in particular to promote the neutralisation / degradation of harmful / undesirable chemical compounds that can undermine people’s health.

[0034] The air purification element 1 has particular application within air purification systems for indoor and / or closed environments.

[0035] The air purification element 1 comprises a printed circuit board (PCB) indicated by the reference number 2, a plurality of light sources 3 and a photocatalytic coating 4.

[0036] In one embodiment, the printed circuit board 2 is of a flexible type, that is to say, it is an electronic circuit that has conductive metal tracks 2a which, as may be observed in figure 2, are printed / applied on a dielectric substrate 2b, which is in turn not rigid. The light sources 3 are applied / coupled directly (i.e. mounted) on the flexible printed circuit board 2, in electrical connection with the conductive tracks 2a thereof so as to be able to receive through the latter the electrical power necessary for their operation.

[0037] In particular, the printed circuit board 2 and the plurality of light sources 3 are produced with the techniques known as “flexible electronics” or with the techniques known as “three-dimensional electronics on plastic” (for example 3D MID or IME), which allow for obtaining a flexible printed electronic circuit, i.e. a flexible printed circuit board.

[0038] Preferably, the light sources 3 are light sources of the LED type, thus making it possible to obtain high levels of efficiency with limited costs and avoiding overheating of the element 1 during the operation thereof.

[0039] Preferably, the light sources 3 are arranged on the printed circuit board (typically flexible) 2 according to a grid, i.e. matrix configuration.

[0040] Even more preferably, the light sources 3 are mounted on the printed circuit board 2 in such a way that the distance between two adjacent light sources is between 0.5 cm and 2 cm, in particular between 0.8 cm and 1 .2 cm, resulting in an optimal use of the available space on the printed circuit board 2 while simultaneously ensuring high levels of performance.

[0041] The photocatalytic coating 4 is applied in direct contact at least on the plurality of light sources 3: in this manner the distance between the light source 3 and the photocatalytic coating 4 is minimised, thus maximising the efficiency of activation.

[0042] In fact, as may be observed in figure 1 , the trend in the luminous power irradiated by the light source 3 in space (substantially the quantity of photons received in a given point in space) is inversely proportional to the square of the distance from the light source 3 itself and displays a cone- shaped diffusion profile (indicated by the reference C).

[0043] Applying the photocatalytic coating 4 on the light sources 3, by contrast, will eliminate the space present between the two, thereby ensuring that the maximum quantity of photons possible per photocatalyst surface unit is received at every moment to activate the photocatalysis process, with a consequent oxidation / neutralisation / degradation of polluting compounds.

[0044] Preferably, as may be observed for example in figure 3, the photocatalytic coating 4 is also applied in direct contact on a surface of the printed circuit board 2 adjacent to (i.e. surrounding) the light sources 3, that is, on the outer layer coating the printed circuit board 2 in the space comprised between the light sources 3.

[0045] In other words, the photocatalytic coating completely coats the entire outer layer of one face of the printed circuit board 2 so as to embed the light sources 3 within it and thus maximise the surface available for the air purification process.

[0046] Preferably, the photocatalytic coating 4 overall has a maximum thickness of 1 millimetre, in particular between 1 micron and 40 micron, or in general a thickness that is sufficient to completely cover the light sources 3.

[0047] Preferably, the photocatalytic coating 4 comprises or is completely made of tungsten trioxide, a readily available low-cost compound having a high activation efficiency, being activatable also with radiation in the visible spectrum. In order to further increase the efficiency of the catalysis process, the photocatalytic coating 4 can comprise one or more doping species consisting of noble metals; in particular, said photocatalytic coating 4 can also comprise, among the various noble metals, silver particles which increase its reactivity and facilitate its activation.

[0048] In accordance with a possible embodiment schematically illustrated in figure 4, the filter 1 comprises a duct-like support 5 without any mandatory geometry, preferably, but without limitation, a tubular support with a circular cross section, which delimits an internal volume.

[0049] Specifically, the printed circuit board 2 (for example flexible) is internally coupled to the duct-like support 5, so as to define an inner wall thereof, in which the photocatalytic coating 4 supported by the circuit 2 is directly facing the internal volume.

[0050] In this manner, a conduit for the passage of air is generated, which extends between two opposite ends 5a, 5b of the duct-like support 5 and along which the air flow can come into direct contact with the photocatalytic coating 4 along the entire length of the duct-like support 5, during the passage of the air flow between the two ends 5a and 5b, as it passes over the photocatalytic coating.

[0051] Furthermore, in this context, the light sources 3 are positioned beneath the photocatalytic substrate 4 and thus in the element 1 as described there exist no components and / or parts apt to slow down and / or limit the passage of air inside the duct-like support 5, and consequently the pressure drop (AP) generated in the air passing between the ends 5a and 5b of the air purification element 1 is practically equal to zero and / or in any case uninfluential.

[0052] Furthermore, the photons generated by a specific light source 3 that should pass through the photocatalytic coating 4 directly overlying it, without, therefore, interacting with it, would strike / bounce / scatter on the facing portion of the photocatalytic coating 4, thus activating it.

[0053] In this manner the risk of photon dispersion is reduced (or possibly eliminated), thus ensuring an optimisation of the overall efficiency of the air purification element 1 , since all the photons generated will interact with and activate the photocatalytic coating 4 (directly overlying or facing).

[0054] In order to further reduce, even eliminate, the risk of photon dispersion, the air purification element 1 can comprise a pair of reflecting elements 6 associated with the respective ends 5a, 5b of the duct-like support 5 and facing the internal volume.

[0055] The reflecting elements 6 operatively make it possible to reflect into the internal volume of the duct-like support 5 any photons following a trajectory that would lead them to pass through the ends 5a, 5b and exit from the element 1 .

[0056] In greater detail, the reflecting / scattering elements 6 have a preferably plate-like shape, which is in general complementary to that of an internal profile of the respective end 5a, 5b, and have a porous and / or perforated and / or woven structure adapted to allow the passage of air with a reduced pressure drop.

[0057] In other words, the reflecting / scattering elements 6 are structurally configured so as not to obstruct the free passage of the air flow through the duct-like support 5, and at the same time they have a reflecting / scattering surface facing the internal volume of the latter which allows the photons generated by the light sources 3 to be reflected / scattered, thus avoiding the dispersion thereof outside the ductlike support 5.

[0058] To this end, the reflecting / scattering elements 6 can have a mesh, grid, porous, spongy, or woven configuration / structure or any analogous structure having openings / channels capable of allowing the passage of air and at the same time they show a reflecting / scattering surface facing towards the internal volume of the duct-like support 5.

[0059] Advantageously, the present invention achieves the proposed objects by overcoming the drawbacks complained of in the prior art and providing the user with a photocatalytic air purification element 1 which has a simple structure and is at the same time capable of maximising the efficiency of neutralisation of harmful chemical species.

[0060] In fact, the application of the photocatalytic coating 4 directly on the light sources 3 makes it possible to maximise the quantity of photons received by the photocatalytic coating 4, while simultaneously leaving the surface completely free so that it can fully interact with the flow of air to be purified which passes over the photocatalytic coating 4.

[0061] Furthermore, the implementation of a printed circuit board (for example flexible) 2 enables the coupling thereof to the duct-like support 5, which defines a flow channel for the air flow whose size (in terms of width and length) can be easily customised based on the specific implementation requirements and which is simultaneously capable of preventing the undesirable dispersion of photons.

[0062] The present invention further relates to a modular air purification unit comprising one or more elements 1 provided with the duct-like support 5, wherein the duct-like supports 5 have a first end 5a couplable to a line for supplying an air flow and a second end 5b couplable to a line for delivering said air flow.

[0063] In other words, the present invention provides a modular unit that can be implemented to upgrade / improve / back up a new and / or existing air treatment system simply by installing the unit along the ducts supplying the recirculation air flows into indoor environments. In addition, the present invention provides a modular unit that can also be a stand-alone unit capable of autonomously treating the air in a closed environment.

[0064] In particular, the number and coupling geometry of the elements 1 in a modular unit can be selected on the basis of the specific dimensions / requirements of the system, resulting in a solution that is customisable based on needs.

[0065] In one embodiment, two or more air treatment elements 1 are arranged parallel side by side.

Claims

CLAIMS1. An air purification element comprising:- a printed circuit board (2);- a plurality of light sources (3) mounted on said printed circuit board (2) and electrically connected thereto;- a photocatalytic coating (4) applied in direct contact at least on said plurality of light sources (3).

2. The air purification element according to claim 1 , wherein the photocatalytic coating (4) is applied in direct contact also on an external surface of one face of the printed circuit board (2) adjacent to the light sources (3).

3. The air purification element according to claim 1 or 2, wherein said light sources (3) are of the LED type and wherein the printed circuit board is flexible.

4. The air purification element according to any one of the preceding claims, wherein the light sources are mounted on the printed circuit board according to a matrix configuration.

5. The air purification element according to any one of the preceding claims, wherein the distance between two adjacent light sources (3) is between 0.5 cm and 2 cm.

6. The air purification element according to any one of the preceding claims, wherein said photocatalytic coating (4) comprises tungsten trioxide doped with silver particles.

7. The air purification element according to any one of the preceding claims, comprising a duct-like support (5) delimiting an internal volume, said printed circuit board (2) being internally coupled to the duct-like support (5) so as to define an inner wall thereof and have the photocatalytic coating (4) directly facing the internal volume.

8. The air purification element according to claim 7, comprising a pair of reflecting and / or scattering elements (6) associated with respective opposite ends (5a, 5b) of the duct-like support (5) and facing the internalvolume.

9. The air purification element according to claim 8, wherein said reflecting and / or scattering elements (6) have a plate-like shape complementary to that of an internal profile of the respective end (5a, 5b) and have a perforated and / or porous and / or woven structure adapted to allow the passage of air.

10. The air purification element according to any one of the preceding claims 7 to 9, wherein the duct-like support (5) is of the tubular type and has a circular and / or square cross section.

11. A modular air purification unit comprising a plurality of air purification elements (1 ) according to any one of claims 7 to 10, wherein said duct-like supports (5) have a first end (5a) couplable to a line for supplying an air flow and a second end (5b) couplable to a line for delivering said air flow.

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