UV disinfection box system

Abstract

The box-type UV disinfection system (100) comprises a plurality of internal UV sources (121, 122, 131, 132, 141, 142) arranged on at least two adjacent walls (120, 130, 140), all of whose internal wall surfaces have a reflectance of more than 80%, preferably more than 87%, in the wavelength range of 250-350 nm, and a UV-transparent support (101) having a UV transmittance of at least 70% in said wavelength range and located at a suitable minimum distance from the bottom wall (110), the UV sources (131, 132, 141, 142) arranged on at least one of the walls (130, 140) being inclined towards the bottom wall (110) at an angle of 5°-30°. Such a system has improved properties in terms of efficiency and, in a preferred embodiment, also better portability.

Description

[Technical field]

[0001] The present invention is specific to a UV disinfection box system having improved properties in terms of efficiency and, in preferred embodiments, improved portability. [Background technology]

[0002] The use of UV irradiation for disinfection of items in compact forms such as "boxes" inside which the items to be disinfected are placed is very widespread and has been known for a long time, as described for example in US Pat. No. 5,399,623 or US Pat. No. 5,499,623, both of which use lamps as the UV source.

[0003] These devices have been continuously improved with regard to preferred UV sources exhibiting a main emission in the so-called UV-C region, as described, for example, in US Pat. No. 5,399,633, which describes an improvement in the germicidal effect achieved by combining UV sources with different UV wavelength emission spectra, more specifically a first UV source with a first wavelength range with an upper limit of at least 270 nm and a second UV source with a second wavelength range with a lower limit of at least 270 nm and an upper limit of at least 320 nm. This patent application also discloses a series of suitable UV sources for UV disinfection boxes, such as low-pressure mercury lamps, UV LEDs or UV chips. UV chips are less common with respect to the other two sources, but are preferred since they are cold sources that do not require a system for thermal shielding or thermal management of the generated heat. More details on this type of source are given in US Pat. No. 5,399,633.

[0004] One aspect to consider in a UV disinfection box is how to maximize the pathogenic microorganisms killing action of the sources, especially when the objective is disinfection of 3D objects (keys, mobile phones, wallets, china and cutlery, glasses, containers, pacifiers, baby bottles, toys, etc.), in order to minimize the number of sources used and / or disinfection process time for cost-related issues and / or process efficiency. More sources and / or longer process times have a negative impact on the power management aspect, which is an issue for "hot" UV sources in terms of thermal management, as addressed, for example, via a heat-spreader in US Pat. No. 5,399,633, but for cold sources, it is an issue to consider in systems that are not powered via a connection to a mains power source, such as battery-powered or solar panel-assisted systems.

[0005] Furthermore, it is necessary to maximize the efficiency of the box while taking into account its impact on the objects to be disinfected. Indeed, it is known that repeated exposure to UV light can degrade plastics, especially UV-C, which is the most effective germicidal radiation. See, for example, Non-Patent Document 1 or Non-Patent Document 2. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] DE 3044181 A1 [Patent Document 2] US Patent Application Publication No. 2007 / 0274879 [Patent Document 3] International Publication No. 2021 / 101431 [Patent Document 4] International Publication No. 2018 / 106168 [Patent Document 5] US Patent Application Publication No. 2021 / 0085812 [Patent Document 6] US Patent Application Publication No. 2013 / 078142 [Patent Document 7] US Patent Application Publication No. 2008 / 265179 [Patent Document 8] US Patent Application Publication No. 2008 / 253941 [Patent Document 9] US Patent Application Publication No. 2016 / 215941 [Patent Document 10] International Publication No. 2011 / 049859 [Patent Document 11] Indian Patent Application No. 202011020635 [Non-patent literature]

[0007] [Non-Patent Document 1] “Damage to Common Healthcare Polymer Surfaces from UV Exposure” by Peter Teska et al., published on “Nano LIFE VOL. 10, NO. 03, 2020 [Non-Patent Document 2] “Ultraviolet light accelerates the degradation of polyethylene plastics”, by Mustafa Dogan, published on Microsc. Res. Tech., 2021 Nov; 84(11):2774-2783 [Non-Patent Document 3] summer 2010, vol.5 Talk letter, by Shimadzu [Non-Patent Document 4] “Ultra-violet reflecting power of Aluminum and several other metals” by William Weber Coblentz et al., Bureau of Standards Journal of Research, volume 4, page 189

Non-Patent Document 5

Summary of the Invention

Problems to be Solved by the Invention

[0008] An object of the present invention is to provide a novel UV box system having improved performance over those of the prior art, particularly with respect to the arrangement and effectiveness of the UV sources used.

Means for Solving the Problems

[0009] The present invention relates to a UV disinfection box system having at least one movable wall, wherein all of the inner wall surfaces of the UV box have a reflectivity higher than 80%, preferably higher than 87%, in the wavelength range of 250 to 350 nm. The UV disinfection box system includes a plurality of separate UV sources disposed on at least two adjacent walls within the UV box and not present on at least one of the UV box walls. The UV box further includes an internal UV-transmitting support disposed at a minimum distance d1 from the base wall and a maximum distance d2 from the opposite upper wall, where 0.1 < d1 / (d1 + d2) < 0.5, preferably 0.15 < d1 / (d1 + d2) < 0.4, and has a UV transmittance of at least 70%.

[0010] Examples of this type of UV disinfection box system can be found in US Pat. No. 5,399,623 and US Pat. No. 5,499,633, as set forth in the preamble of claim 1, from which specifications the invention is distinguished by the fact that a separate UV source arranged on at least one of the walls is inclined towards the bottom wall at an angle between 5° and 30°.

[0011] As will be apparent from the following description and from the schematic drawings of the preferred embodiment, the term "adjacent walls" is intended and should be interpreted as walls having a common boundary.

[0012] The preferred method of characterizing UV reflectance and UV transmittance is by measurement in an integrating sphere, as outlined in [3]: this allows the contribution of so-called diffuse reflectance to be properly assessed as well.

[0013] The inventors have found that the above solution, thanks to the synergistic effect of all the above elements, makes it possible to irradiate all surfaces of objects placed in the box with a sufficiently high UV irradiance, even if one or more of the box walls do not have a separate UV source (in a preferred embodiment, one of the box walls without a UV source is the bottom wall), which makes it possible to achieve adequate disinfection with a pathogenic microbial inactivation level of at least 99.9% on all object surfaces exposed to the internal volume V, and on surfaces not directly facing a separate UV source, with low power energy, in a single disinfection cycle, usually lasting from 30 seconds to 6 minutes, most typically from 40 seconds to 3 minutes.

[0014] Suitable UV sources are UV-C light emitting diodes (UV-C LEDs), UV chips as described in the aforementioned patent document 4, and other UV-C mercury-free lamps, such as UV excimer lamps. The use of UV chips is preferred as it provides a strong inactivating effect against bacteria and viruses as a result of a specific spectrum with a first peak in the range of 260-280 nm, a second peak in the range of 290-310 nm, and a continuous emission between 250-320 nm with a main intensity peak at about 265 nm. It is possible to have a single separate UV source emitting UV radiation having both the first and second spectral radiation peaks, or a first separate UV source emitting radiation centered on the first peak and a second separate UV source emitting radiation centered on the second peak.

[0015] The invention is further explained with the aid of the following figures. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is a schematic diagram of a first embodiment of a UV box according to the present invention; [Diagram 2] FIG. 4 is a schematic diagram of a second embodiment. [Diagram 3] FIG. 2 is a schematic top view of the first embodiment shown in FIG. 1 in an "unfolded" configuration. [Figure 4A] 1 shows two schematic diagrams of a UV box configuration according to the present invention, as well as three comparative examples that were tested and illustrated herein. [Figure 4B] 1 shows two schematic diagrams of a UV box configuration according to the present invention, as well as three comparative examples that were tested and illustrated herein. [Figure 4C] 1 shows two schematic diagrams of a UV box configuration according to the present invention, as well as three comparative examples that were tested and illustrated herein. [Figure 4D] 1 shows two schematic diagrams of a UV box configuration according to the present invention, as well as three comparative examples that were tested and illustrated herein. [Figure 4E]1 shows two schematic diagrams of a UV box configuration according to the present invention, as well as three comparative examples that were tested and illustrated herein. [Figure 5A] A schematic diagram of the inside of a UV box. [Figure 5B] Detail of the liftable element 501. [Figure 5C] 13 is a detailed view of a support 5010 as a modified example of a liftable bar shape. [Figure 6] 5A-5C, according to another embodiment, a schematic diagram of the inside of a UV box. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] In the above figures, the dimensions and dimensional ratios of the elements shown are not necessarily accurate and in some cases they have been altered to improve their understanding, in particular referring non-exclusively to the thickness and dimensions of the walls of the UV source relative to the dimensions of the box walls. Furthermore, elements that are not necessary for the understanding of the figures and are common knowledge to those skilled in the art, such as electrical connections of the power supply, electronic components and driving units, are not shown.

[0018] A schematic diagram of a UV box 100 according to a first embodiment is shown in Figure 1 and has three pairs of separate UV sources located on the inner surfaces of three walls: UV sources 131 and 132 are on side wall 130, UV sources 141 and 142 are on the opposite side wall 140, and UV sources 121 and 122 are on top wall 120. The other three UV box walls, namely front wall 150, bottom wall 110 and back wall (not shown), do not have separate UV sources attached thereto and the UV box is shown in an "open" state with front wall 150 connected only to bottom wall 110.

[0019] Between the bottom wall 110 and the top wall 120, there is a UV transmissive support 101, and its positioning is important to ensure efficient irradiation from below the object to be disinfected. Such positioning is defined by the above formula 0.1 < d1 / (d1 + d2) < 0.5, that is, it should be between 10% and 50% of the distance between the bottom wall 110 and the top wall 120 (i.e., the height of the UV box), and this condition represents the necessity for the UV transmissive support 101 to be located at a certain appropriate distance from the bottom wall 110. In this regard, d1 indicates the minimum distance between the support 101 and the bottom wall 110 when the support 101 is inclined and / or does not have a flat shape, and d2 indicates the maximum distance between the support 101 and the top wall 120 when the support 101 and / or the top wall 120 is inclined and / or does not have a flat shape.

[0020] As shown in FIG. 1, since the front wall 150 needs to be displaced / moved to open and close the UV box 100, the presence of the UV source poses some constraints on their power supply, so it is preferable that there is no UV source. The separate UV sources 121, 122 have outgoing UV radiation with a main component orthogonal to the wall to which they are attached, and have an angular emission distribution of 100° for a standard UV chip and 120° - 130° for a standard UV LED.

[0021] The UV sources 131, 132 arranged on the first side wall 130 and the UV sources 141, 142 arranged on the opposite side wall 140 are attached at a specific downward inclination included between 5° and 30°, whereby their main emission forms a smaller angle included between 85° and 60° rather than being perpendicular to the attachment walls 130, 140, that is, it is directed towards the bottom wall 110.

[0022] It should be noted that it is not necessary for all separate UV sources to have an emission "inclined" towards the bottom wall 110, but this requirement is met by at least all UV sources mounted on the walls, preferably the side walls. More preferably, all separate UV sources except for the one mounted on the top wall 120 have an emission inclined towards the bottom wall 110.

[0023] Another way to achieve tilted UV emission is shown in the second embodiment of Fig. 2, outlining the structure of a UV box 200 with inwardly inclined side walls 230, 240 due to the trapezoidal cross-sectional shape of the UV box, with a top wall 220 smaller than the bottom wall 210. All UV sources 221, 222, 223 and 241, 242, 243 are mounted parallel to the walls 220 and 240 respectively (i.e. the direction of the main emission is perpendicular to their mounting walls), but for UV sources 241, 242, 243 the main emission is inclined towards the bottom wall 210 due to the inclination of the side wall 240. The inclination angle of the side walls carrying the UV sources with respect to the bottom wall 210 is between 60° and 85°.

[0024] Since sidewall 240 satisfies the slope requirements of the present invention, sidewall 230 may be perpendicular to bottom wall 210 as in the first embodiment, or may be sloped outward (in which case the cross section more closely resembles a parallelogram) if this is useful for proper reflection of UV radiation, even if the preferred configuration is that shown in FIG. 2, where sidewall 230 mirrors sidewall 240 carrying a separate UV source.

[0025] It is important to emphasize that the UV box of the present invention is not limited to a particular number of UV sources or a particular arrangement of the box walls, so long as they meet the more general requirements set out in claim 1. That said, a preferred configuration envisages the use of six separate UV sources, in one case evenly distributed over three walls with two UV sources for each wall (as in the embodiment of FIG. 1), or evenly distributed over two walls with three UV sources for each wall (as in the embodiment of FIG. 2). A second preferred configuration envisages the use of four separate UV sources distributed over three walls, most preferably two UV sources on the top wall and one UV source on each side wall.

[0026] In terms of the power output of such UV sources, the most efficient and low-consumption systems have a ratio of the cumulative power P of the separate UV sources to the internal volume V of 0.25 to 0.60 mW / cm 3 Indicates the interval.

[0027] All UV boxes according to the invention can be made of a rigid structure with only movable panels to open and close the box, or they can be made with foldable / joinable panels, as illustrated in Fig. 3, which represents a view from above in the unfolded state of the assembled UV box 100 shown in Fig. 1. As already mentioned above, UV sources 131 and 132 are attached to the box panel 130 (first side wall), UV sources 141 and 142 are attached to the box panel 140 (second side wall), UV sources 121 and 122 are attached to the box panel 120 (top wall), while panels 110 (bottom wall), 150 (front wall) and 160 (rear wall) do not provide a UV source. The electrical connections between the UV sources and the electronic control and power drive units can be located on the panels or embedded in the panels.

[0028] As shown in the exemplary embodiment of FIG. 5, the electronic control components and power drive unit (as well as any other electrical or logical elements) can be disposed within a container 511, the upper surface of which is the base 510 of the UV box 500, or alternatively attached to the base of the UV box.

[0029] Figure 3 shows the panels already joined together so that the box can be folded in the assembled state, but they can be completely separated and joined together via suitable adhesive strips, connected or connectable via hinges, or the panels can be provided with semi-permanent joints so that they can be folded without the need for the box walls to be completely separated after the initial setting. When the panels are unfolded, a compact and small structure can be obtained, preferably with a ratio between its internal volume V and the volume of the unfolded box ranging from 4 to 16, in such a way that the system can be easily stored or transported and easily reassembled for operation. The separate UV sources 131, 132, 141, 142, represented by solid circles, are inclined relative to the mounting walls 130, 140, while the separate UV sources 121, 122, represented by open circles, are mounted parallel to the wall 120, since this will be the upper wall of the UV box once assembled.

[0030] In the case of UV boxes with separable walls, they can be stored in a suitable container that also contains the electronic module and its components; a preferred solution in this regard is container 511 in FIG.

[0031] A common feature that all UV box embodiments according to the present invention have is a high reflectivity of the inner surface of the UV box wall (i.e. the surface of the wall facing the internal volume V), more specifically such reflectivity should be >80%, preferably >87% in the wavelength range of 250-350 nm.

[0032] A suitable material for the inner surface of the UV box is a porous fluoropolymer layer, in particular expanded PTFE (e-PTFE) or porous PTFE, specifically Porex Virtek™ (supplied by Porex), with an average UV reflectance of 94% for a 0.75 mm thick layer and 91% for a 0.5 mm thick layer. Special UV-reflective aluminum layers also have a suitable high UV reflectance (90% or more), for example the UV-C micro-aluminum reflector by Alanod with a UV reflectance of 90% or more, or the Vega UV-C aluminum surface with nanometer PVD layer by Almeco with a UV reflectance of 91% or more. With the above solutions, a higher UV reflectance can be achieved, which is a very important aspect in minimizing the number of UV light sources. In this respect, it is important to emphasize that in standard UV boxes, a standard Al reflector layer is usually used, achieving a UV reflectance of up to 75%. This is exemplified in Non-Patent Document 4 or Non-Patent Document 5 (see especially FIG. 1).

[0033] Devices based on external light emission for disinfection, such as described in US Pat. No. 6,239,663, or lighting systems with disinfection as an additional feature, such as described in US Pat. No. 6,239,663 and US Pat. No. 6,239,663, rely on the reverse mechanism (light emission) to achieve disinfection. On the other hand, another possibility is to achieve exposure of the entire object to UV radiation by translation / rotation of the UV source, as described in US Pat. No. 6,239,663.

[0034] Another common feature shared by all UV box embodiments according to the invention is the UV transmission properties of the support towards the object to be disinfected, which should be at least 70% in the range of 250-350 nm. As already outlined for the reflectance of the UV box walls, the transmittance can also be characterized by an integrating sphere.

[0035] This effect can be achieved using UV-transmitting materials, such as some thin fluoropolymer foils (typically with thicknesses in the range of 120-300 μm) with good UV transmission properties, such as UV-transmitting fluoropolymers like THV (polymer of tetrafluoroethylene, hexafluoropropylene and vinylidene fluoride) or ETFE (ethylene tetrafluoroethylene). With these exemplary materials it is possible to achieve a UV transmission of the support of more than 70%, for example a 0.18 mm thick THV support has a UV transmission of more than 75%.

[0036] Special thin sheets of UV-transmitting synthetic glass can also be used to advantage, but they are less preferred because they are usually more fragile and sensitive to mechanical shock. Another solution is to use net structures with a void-to-fill ratio of 3 to 200.

[0037] The supports may be independent elements supported by suitable posts of suitable height, or flat elements inserted into suitable grooves in the box internal structure, or the supports are hinged to the side walls to allow folding of the box made of foldable / separable panels. In this case, the possibility of having two half-width supports each hinged to a wall is also envisaged, such that the assembly of the UV box results in the formation of a support by bringing two half-width supports together.

[0038] Another preferred solution for the support is shown in Fig. 5, which shows a perspective view of a UV box 500 with the front and right panels removed, having a receptacle 511 coupled to or forming a bottom wall 510. UV sources 521, 522, 531, 532 are arranged in two adjacent walls, namely the top wall 520 and the side wall 530, respectively. The bottom receptacle 511 contains the UV box electronics, control and power supply means (not shown). In the UV box 500, the support is made by a series of liftable elongated lateral elements (bars) 501, 501', 501'', 501''', rotatably mounted on the bottom wall 510, each of them having a conventional system (not shown) for locking / unlocking them in position on the bottom wall 510.

[0039] FIG. 5B details a single liftable element 501 in two positions: a "rest" position represented by dotted lines, and a raised position shown in solid lines.

[0040] It is emphasized that the invention is not limited to any number of liftable elements, to a particular material or shape, or to a lateral arrangement. With regard to the liftable bar shape, an interesting variant is shown in the partial front view of Fig. 5C, where the support 5010 presents a recess 5011 useful for avoiding rolling of cylindrical objects with narrower dimensions, e.g. a thermometer.

[0041] All the liftable elements may be controlled, i.e. lifted separately or alternately, and they may be connected together in such a way that only lifting one of them, preferably the most easily accessible one, such as the one closest to the opening wall, causes the others to be moved to a lifted position as well. For example, as shown in the perspective view of Fig. 6, a UV box 600 presents four liftable bars 601, 601', 601'', 601''', connected to each other by connecting rods 6010 rotatably fixed to the bars in any suitable way.

[0042] Finally, it is emphasized that in this embodiment, the relationship of the distance of the support from the bottom and top walls of the UV box should be measured from the elevated element portion that defines the stationary surface of the object to be treated by UV irradiation.

[0043] In a preferred embodiment, the UV box is powered via a rechargeable battery, and in the most suitable variant, via one or more solar panels mounted on the exterior surface of the UV box wall. If necessary, a charge controller can be used to optimize the charge and discharge cycles.

[0044] The battery and any drive or control electronics including switches and user interface panel may be separable elements from the UV box or, more preferably, may be permanently connected to the UV box, this latter solution being preferred in the case of a foldable or collapsible UV box.

[0045] An optional element advantageously present in the UV box according to the invention is a safety interlock switch that switches off the UV source when the box is open, avoiding powering the box if it is not properly assembled or if it is accidentally opened during the disinfection process. Also, although less relevant, a UV sensor or exposure meter may be included.

[0046] The present invention, its principles and advantages are further illustrated by the following non-limiting examples. EXAMPLES

[0047] Photometric measurements were performed to measure the UV irradiance generated within a collapsible UV system with a rectangular parallelepiped shape and disinfection volume dimensions of approximately 30 cm × 15 cm × 15 cm (L × W × H). The system delivered an accumulated power P of 3 W (ratio P / V = 0.44 mW / cm) according to the configuration shown in Figure 1.3 The disinfection volume was equipped with six UV sources powered by a 1000W UV light source. The walls were coated with a 0.75 mm thick highly UV-reflective porous PTFE layer (Porex Virtek™ foil) and the UV sources were UV chips manufactured by LightLab Sweden AB, each with a UV output of 10 mW and generating an irradiation with an emission peak centered at 265 nm and a second lower peak centered at 305 nm. The UV irradiance inside the disinfection volume was measured by a UV sensor module UVM-30A, adapted and calibrated to have a good response in the range of 200-370 nm and connected to a suitable acquisition system.

[0048] With the sensor facing upwards towards the top UV source, the UV irradiance measured in the central area of ​​the system at a height of approximately 4 cm from the base was 140 μW / cm 2 The UV irradiance values ​​were also measured in the central area of ​​the UV box by placing the sensor on a 180 μm thick UV-transparent THV support, with its sensitive area facing the box base, i.e. facing a surface without active UV generation. This arrangement reflects what happens to the surfaces of 3D objects, which are not exposed to direct UV irradiation, but only to UV incident via (multiple) reflections on the highly reflective inner surfaces of the walls.

[0049] The average UV irradiance measured for different distances of the support from the base, and the highest measured value (116 μW / cm 2 The relative values ​​of the same UV irradiance normalized to the UV radiation intensity are reported in Table 1 below.

[0050] [Table 1]

[0051] It is possible to observe that a relatively high UV irradiance above 70 can be achieved only when the distance range specified by the present invention, i.e., 0.1 < d1 / (d1 + d2) < 0.5, is satisfied, and such values are defined as the threshold for an efficient UV box system. This is because lower values result in too low a disinfection effect caused by the reflected irradiation. Also, a UV system according to a preferred embodiment, i.e., having 0.15 < d1 / (d1 + d2) < 0.4, shows enhanced efficiency, and more specifically, it is also possible to observe that the relative UV irradiance sufficiently exceeds 85.

Example

[0052] Photometric measurements were carried out to determine the UV irradiance generated within the same foldable UV system having the cuboid shape and dimensions described in Example 1, but with different arrangements of UV sources as shown in FIGS. 4A - 4E of the schematic diagrams C1, C2, S1, C3, S2 of the UV system. ·A) Comparative Example C1: Six UV sources are arranged at equal distances from each other on a single wall, which is the upper wall of the UV system, and the main component of the emitted UV irradiation is made orthogonal to both the mounting wall surface and the box base. ·B) Comparative Example C2: Two sets of three consecutive UV sources are attached to the central regions of two adjacent walls, i.e., the side wall and the upper wall, such that they are equidistant from the edges of the wall. In this case as well, the main UV irradiation is orthogonal to the mounting wall. ·C) Example S1: The arrangement of the UV sources is the same as in Comparative Example C2, but the UV sources are attached to the side wall at an angle of 10° towards the bottom wall. ·D) Comparative Example C3: In this case, two sets of three consecutive UV sources are attached to three walls, the upper wall and two adjacent side walls. On each wall, the UV sources are equidistant from each other and are attached to the central region of the wall, and the main emission is orthogonal to the mounting wall. ·E) Example S2: The arrangement of the UV sources is the same as in Comparative Example C3, but the UV sources are attached to the side wall at an angle of 20° towards the bottom wall.

[0053] The UV irradiance in the system was measured in the same way as in Example 1, using the same UV sensor module UVM-30A. The UV irradiance was then also measured by rotating the sensor 90° to face the back wall and then the side wall where there was no UV source, except for configurations D) and E), where the UV source was present on both side walls, but not directly in front of the sensor. Additional UV measurements were performed by placing the UV sensor 3.5 cm from the side wall without a UV source for configurations B) and C), or from either side wall for configurations D) and E).

[0054] The average relative UV irradiance values ​​(normalized to the highest value) measured for the different configurations are reported in Table 2 below.

[0055] [Table 2]

[0056] From the above relative values, it can be seen that the configuration with light sources on multiple walls is better than the configuration with a light source mounted on a single wall (Comparative Example C1) and has a more uniform distribution of reflected irradiation in all directions. Furthermore, it should be noted that if the object to be disinfected is bulky, mounting the UV source on a single wall will result in a large shadow effect induced by the object, which will significantly reduce the reflected irradiation.

[0057] Furthermore, configurations with light sources distributed over more walls (three walls, as in D and E) are better than configurations with light sources distributed over fewer walls (two walls, as in B and C), and in any case, tilting the UV light sources on the side walls to create an angle of 70°-80° between the direction of their main emission and the direction of the main emission from the UV light source mounted on the top wall is suitable to improve the intensity of the reflected irradiation. Indeed, in a direct comparison of the results obtained with the same configurations, Comparative Example C2 is worse than Example S1, and Comparative Example C3 is worse than Example S2.

[0058] For UV sources mounted on the sidewall at angles below 60°, i.e., tilted more than 30° towards the base, it was found that the added benefit to the reflected irradiation was not significant. EXAMPLES

[0059] Additional photometric measurements were performed using the UV system configuration of Example S1 with different reflective coating layers. a) Aluminum reflective sheet with an average reflectance of close to 90% in the UV range; b) A 0.75 mm thick porous PTFE layer (Porex Virtek™ foil) with an average reflectance in the UV range of 94%.

[0060] The UV irradiance was measured as in Example 1 and the average relative UV irradiance was 7% lower for coating a) versus coating b).

[0061] Therefore, the best coating is represented by a 0.75 mm thick highly reflective porous PTFE, with the preferred coating thickness being 0.20-1.50 mm.

[0062] To improve the UV reflectance of aluminum, high purity (>99.9%) metal coatings up to 500 nm thick, produced for example by sputtering, have proven suitable, with Al and Ag being the preferred metals for this purpose and effect. EXAMPLES

[0063] A system manufactured according to a second embodiment of the invention, i.e. defined as Example S3, having a trapezoidal cross section with bottom wall dimensions of 22 cm x 30 cm, top wall dimensions of 15 cm x 30 cm and height of about 14 cm, was evaluated and compared with a commercially available system with a UV source on the top wall and a standard Al surface with reflectance < 80%. The main characteristics of the S3 system and the commercially available comparative examples C4 to C6 are highlighted in Table 3 below and the intended performance as the time required to achieve a disinfection level of 99.9% is reported in Table 4 below.

[0064] [Table 3]

[0065] [Table 4]

[0066] It can be observed that the system according to the invention is not only the fastest, but also the most efficient system, with the lowest power per unit volume (P / V) ratio, requiring less than half the cumulative power of a comparable size (C5), even though it has the largest internal volume.

[0067] Each of the above examples explores the effect of a particular feature of the UV box of the present invention, whose coexistence and synergistic effects can achieve a UV disinfection box system with enhanced properties over those of the prior art.

Claims

1. A box-type UV disinfection system (100; 200; 500; 600) having at least one movable wall (150), a plurality of separate UV sources (121, 122, 131, 132, 141, 142; 221, 222, 223, 241, 242, 243; 521, 522, 531, 532) located within but absent from at least one wall; an inner UV-transparent support (101; 201; 501, 501', 501'', 501'''; 601, 601', 601'', 601'''); Equipped with All of the interior wall surfaces have a reflectivity of greater than 80% in the wavelength range of 250 to 350 nm; the separate UV sources (121, 122, 131, 132, 141, 142; 221, 222, 223, 241, 242, 243; 521, 522, 531, 532) are arranged on at least two of its walls (110, 120, 130, 140, 150, 160; 210, 220, 230, 240; 510, 520, 530) adjacent to one another; said UV-transparent support (101; 201; 501, 501', 501'', 501''', 601, 601', 601'', 601''') has a UV transmittance of at least 70% in the wavelength range of 250 to 350 nm and is arranged at a minimum distance d1 from the bottom wall (110; 210; 510) and a maximum distance d2 from the opposite top wall (120; 220; 520), wherein 0.1<d1 / (d1+d2)<0.5; A box-type UV disinfection system, characterized in that a separate UV source (131, 132, 141, 142; 241, 242, 243; 531, 532) arranged on at least one of the walls (130, 140; 240; 530) is inclined toward the bottom wall (110; 210; 510) at an angle of 5° to 30°.

2. 2. The box-type UV disinfection system (100; 200; 500; 600) of claim 1, wherein the at least one wall without a separate UV source is the bottom wall (110; 210; 510) or a movable wall (150).

3. 2. The box-type UV disinfection system (100; 200) according to claim 1, wherein the UV-transparent support (101; 201) is a mesh-like structure having a void-to-fill ratio comprised between 3 and 200.

4. 2. The box-type UV disinfection system (100) according to claim 1, wherein the inclination of the separate UV sources (131, 132, 141, 142) is obtained by mounting them at an angle relative to the wall to which they are mounted.

5. 2. The box-type UV disinfection system (200) of claim 1, wherein the inclination of the separate UV sources (241, 242, 243) is obtained by the inclination of the side wall (240) to which they are attached.

6. A box-type UV disinfection system (200) as described in claim 5, wherein the cross-sectional shape of the box is trapezoidal.

7. 2. The box-type UV disinfection system (100; 200; 500; 600) according to claim 1, wherein the number of separate UV sources (121, 122, 131, 132, 141, 142; 221, 222, 223, 241, 242, 243) is six and is evenly distributed on two or three walls.

8. 2. The box-type UV disinfection system (100; 200; 500; 600) of claim 1, further comprising a separate power supply module suitable for coupling with the separate UV sources (121, 122, 131, 132, 141, 142; 221, 222, 223, 241, 242, 243; 521, 522, 531, 532).

9. 2. The box-type UV disinfection system (100; 200; 500; 600) of claim 1, wherein power supply modules for the separate UV sources (121, 122, 131, 132, 141, 142; 221, 222, 223, 241, 242, 243; 521, 522, 531, 532) and other electronic components, optionally including an energy storage rechargeable battery, are embedded in the system outside the internal volume V.

10. 10. The box-type UV disinfection system (500) of claim 9, wherein the power supply module and other electronic components are housed within a container (511) coupled to or forming the bottom wall (510).

11. 2. The box-type UV disinfection system (100; 200; 500; 600) of claim 1, further comprising one or more safety interlock switches suitable for turning off the separate UV sources (121, 122, 131, 132, 141, 142; 221, 222, 231, 232, 241, 242, 243; 521, 522, 531, 532) when the box is opened or for preventing their power supply if the box is not properly assembled.

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