Disinfection system, manufacture and use thereof

FIELD OF THE INVENTION

The invention relates to a disinfection system, the manufacture of such a disinfection system, and the use of such a disinfection system.

BACKGROUND OF THE INVENTION

Disinfection systems use UV radiation, preferably UVC radiation, to disinfect surfaces and/or air in areas where a high level of hygiene is desirable, such as kitchens, children's bedrooms, hospital rooms, class rooms, offices, laboratories, store rooms and operation chambers. UVC radiation has a wavelength shorter than 280 nm, available under typical circumstances in air from 200-280 nm. UV radiation with longer wavelengths includes UVA (315-400 nm) and UVB (280-315 nm), but UV radiation is generally less effective for disinfective purposes at these wavelengths. Sources of UVC radiation comprise low pressure mercury germicidal lamps, and are well known in the art. As UV radiation is unsuitable to provide visibility in working areas, typically also a regular lamp emitting visible light is present in the same space.

The Swiss patent CH 559 885 describes a combination of a regular lamp and a UV disinfection lamp, wherein a regular lamp provides visible light and one or two UV radiations provided with reflectors and lamellae provide disinfection. The reflectors and lamellae can be adjusted to direct the UV radiation away from persons working under the visible light, as UV radiation is potentially harmful to persons. When the lamp mounted on a ceiling, the regular lamp is directed downwards in order to provide a good visibility, whereas the UV radiation is directed upwards and sideward, disinfecting the top portion of the room.

It is a disadvantage of the known disinfection lamp combined with a visible lamp that it is relatively bulky. It is an object of the invention to provide a simpler and more compact disinfection system capable of providing disinfecting UV radiation as well as other types of radiation, in particular visible light, and a more favourable energy consumption.

SUMMARY OF THE INVENTION

The invention provides a disinfection system, comprising a housing provided with at least one lamp mount for mounting a UV lamp, at least one UV radiation opening adjacent to the lamp mount allowing for the output of UV radiation, wherein the disinfection system also comprises at least one conversion means suitable for converting at least part of the UV radiation from the UV lamp to converted radiation of a longer wavelength. Such a disinfection system is relatively simple, as when fitted with only a single suitable UV lamp or germicidal lamp it allows the production of both disinfecting UV radiation as well as other useful types of radiation, in particular visible light, produced by the conversion of UV radiation by the conversion means. Thus, no separate lamp dedicated to a radiation type other than UV radiation is needed, allowing for a much simpler and compact design. Optionally, one or more additional, separate general lighting lamps may be added to increase the amount of visible light coming from the system. Also, the disinfection system according to the invention is more energy-efficient, as a larger amount of the generated UV radiation is used. In known UV lamps, a large fraction of the generated UV radiation is absorbed by the housing. The lamp mount can be suitable for any known type of UV radiation, and is provided with all necessary electrical power means needed to operate a UV radiation source. UV lamp is not restricted to lamps such as mercury vapour lamps, but may also include other UV sources such as UV-emitting LEDs. The housing is typically provided with mounting means for attaching the housing to a wall or ceiling. The conversion means typically comprise conversion materials for converting UVC light to useful radiation of other wavelengths are known in the art, and may take any conceivable form. Particularly useful conversion materials comprise a phosphor or a mixture of phosphor, due to their high stability and durability. Preferably, the conversion means comprise conversion material suitable for the conversion of UV radiation to visible light. Most preferably, the conversion materials are suitable for the conversion of UV radiation to essentially white light. E.g. light that as perceived as white light by a user. Such light is ideally suitable for working conditions. Numerous suitable phosphors are known in the art and commercially available, commonly applied as mixtures in order to obtain white light or any other desired colour.

It is advantageous if the conversion means comprise conversion material suitable for the conversion of UV-C radiation to UV-A radiation. UV-A is suitable to attract and exterminate insects, while at the same time contributing to disinfection of the air in the room. Typically suitable converter materials for conversion of UV-C to UV-A are europium-

doped strontium fluoroborate (SrB ₄ OvFiEu ₂ ⁺ ), europium-doped strontium borate (SrB ₄ OvIEu ₂ ⁺ ) or lead-doped barium silicate (BaSi ₂ OsIPb ⁺ ).

Preferably, the housing comprises at least one reflector for reflecting at least part of the UV radiation from a mounted UV lamp towards the conversion means. Thus, the UV-C radiation is effectively used to produce converted radiation such as UV-A and/or visible light. The reflector may have any suitable shape.

Preferably, the conversion means comprise a cover plate adjacent to the lamp mount, provided with a conversion material. Thus, the window can be used as a collector of UV radiation and is also emitting the generated converted electromagnetic radiation. Preferably, the window is translucent for the generated radiation and absorbs UV-C radiation and in particular suitable for visible light. Suitable glass types with UV-absorbing properties are available and known in the art. The best conversion efficiency is obtained if the conversion material is applied on the side of the window facing the UV-lamp.

In a preferred embodiment, the conversion material is arranged in a layer deposited on the cover plate. Thus, the UV-C radiation is effectively absorbed by the conversion material deposited on the window, yielding an effective conversion of the UV-C radiation to for instance visible light. The amount of conversion material is preferably sufficient to completely absorb UV-C radiation (depending on the intensity of the used lamp), ensuring that only the converted radiation, e.g. visible light, is emitted by the window. It is advantageous if the housing is suitable for mounting on a mounting surface, wherein the UV opening is directed essentially in the plane of the mounting surface. In case of mounting on a ceiling, the direction of UV-C radiation allows for thorough disinfection of surfaces and air near and in the plane. In particular in rooms it is important to direct the UV-C radiation along walls (preferably only upwards) and/or ceilings away from the center of the room, in order to minimize the risk of exposure of persons in the room to the potentially harmful UV-C radiation.

Preferably, at least part of the conversion means are arranged to radiate converted radiation, in particular visible light, essentially away from the mounting surface. Thus, in case the plane is a ceiling or a wall, the converted radiation, in particular visible light, is directed towards the center of the room, where it is usually most useful. At the same time, the UV radiation opening is directed essentially perpendicular to the mean direction of the translucent window, ensuring that persons may enjoy the converted radiation/visible light, while avoiding exposure to UV-C radiation.

In a preferred embodiment, the UV radiation opening is provided with lamellae for directing UV radiation from an UV radiation source mounted in the lamp mount. Lamellae allow for a more precise direction of UV-C radiation. Typically, lamellae preferably comprise UV absorbing material in order to avoid scattering or reflections that could potentially lead to unwanted exposure of persons to UV-C.

Preferably, the lamellae are formed by multiple lamellar elements, wherein the lamellar element comprises at least one lamellar plate, provided with at least one separator element defining the distance between the stacked lamellar plates. Such lamellae are relatively easy to construct and to replace. The lamellae may for instance be straight or aimed under an angle.

In a preferred embodiment, at least part of the housing facing the lamp mount is provided with a photo-catalytic coating, preferably comprising rutile titanium dioxide. The photocatalytic coating is a coating capable of breaking down organic material, in particular dust particles and germs, under the influence of UV-C radiation. Such a housing is essentially self-cleaning. Generally, the involved mechanisms include the generation of radical species. Rutile titanium dioxide is preferred as a catalyst, as it is readily available and environmentally acceptable. However, also other photo catalytically active compounds such as silver ions may also be used.

Preferably, at least the lamellae are provided with a photo-catalytic coating, preferably comprising rutile titanium dioxide. In such case, the coating has a dual function: preventing UV-reflection scattering by absorbing a part of the UV-C radiation, as well as providing improved air cleaning.

It is advantageous if the housing is provided with at least one ventilator. Such a system has an improved disinfection and air cleaning efficiency. Also, the increased air stream helps cooling the UV-lamp. The ventilator may take the form of an electrically powered fan (or multiple fans), for moving air in and out of the housing, for through the lamellae and over the lamp.

In a preferred embodiment at least one UV lamp capable of emitting UV-C radiation is mounted on the lamp mount. Such UV lamps are known in the art. The most suitable type of lamp depends on the application of the lamp. The UV-C lamp irradiates the conversion means, resulting in conversion of part of the UV-C radiation to radiation of a lower wavelength, such as visible light.

The invention also involves a method for the manufacture of a disinfection system according to the invention as described above, comprising the steps of providing a

housing provided with at least one lamp mount for mounting a UV lamp, at least one UV radiation opening adjacent to the lamp mount allowing for the output of UV radiation, positioning in the housing of conversion means suitable for converting at least part of the UV radiation from the UV lamp to converted radiation of a longer wavelength, and mounting a UV radiation source in the lamp mount. This is a relatively simple way of constructing such a disinfecting system.

Preferably, the UV radiation opening is provided with lamellae, wherein the lamellae are formed by stacking multiple lamellar elements, wherein the lamellar element comprises at least one lamellar plate, provided with at least one separator element defining the opening between the stacked lamellar plates. This is a relatively simple and fast way of constructing lamellae for aiming UV radiation with high accuracy. The separator elements define the distance between adjacent lamellae.

The invention further provides the use of a disinfection system according to invention for the disinfection of air. The disinfection provides a relatively simple and compact solution to do so, with the added advantage of also providing other radiation, in particular visible light.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be further disclosed using the following non-limiting examples.

Figure 1 shows a disinfection system according to the invention.

Figure 2 shows a method of assembling a disinfection system according to the invention.

Figure 3 shows applications of a disinfection system according to the invention.

DETAILED DESCRIPTION OF EMBODIMENTS

Figures Ia and Ib show a disinfection system 1 according to the invention. Electronics such as wiring are not shown for the sake of clarity. The housing 2 comprises stacked lamellae 3, a mounting plate 4 for mounting the system 1 to a ceiling or wall, a lamp mount 5 for mounting a UV-C emitting lamp 6, and a cover plate 7 provided with a translucent window 8. The lamellae 3 define multiple UV radiation openings 11 through which UV light from the lamp 6 is radiated out of the housing 2. The housing 2 is provided with two fans 9 for ventilation of the housing, directing air past the lamp 6 for cooling. The

translucent window 8 is made of glass which absorbs UV-C radiation but is translucent to visible light. On the side facing the UV lamp 6, the cover plate 7 is covered with a phosphor layer 10, selected to convert UV-C radiation to a longer wavelength, preferably visible light, which is emitted away from the mounting plate 4 (arrow 'VIS'). Optionally, the phosphor layer can be a phosphor for the conversion of UV-C radiation to UV-A radiation. In this way an insect trap luminary can be produced that also disinfects the air. The side of the mounting plate 4 facing the lamp 6 is provided with a UV-reflective layer 15 directed towards the window 8, in order to improve the efficiency. The UV radiation (arrows 'UV') directed essentially in the plane of the mounting plate 4 through the lamellae 3, in order to prevent UV light reflected in the downward direction. The stacked lamellae 3 are covered with UV absorbing material comprising rutile titanium dioxide. The rutile titanium dioxide acts as a photo-catalyst, helping to auto-clean the lamellae as well as improving the air disinfecting efficiency. The stacked lamellae 3, mounting plate 4 and cover plate 7 are kept together by four pins 12 extending through the stacked layers. The disinfection system 1 shown here has a square configuration, but the shape may be varied.

Figure 2 shows a method of assembling a disinfection system according to the invention, for instance the one shown in figure 1. The progression of the method of assembly is shown from left to right. On the left (a), a pin 20 is mounted on a plate 21, for instance a mounting plate or cover plate as shown in figure 1. In the second phase (b), multiple lamellae 22 provided with a hole 23 fitting the pin are stacked on top of each other, leading to a stack 24 of lamellae in the middle figure (c). Using a die 25, the lamellae 22 are pressed closely together, as shown in the fourth figure (d). Finally, a second plate 26 is placed on top of the stack 24, thus completing the housing. The height of the separator elements 27 of the lamellae 22 define the distance 28 between adjacent lamellae 22, This offers a very easy and convenient and rapid way of assembling a housing with lamellae for a disinfection system according to the invention.

Figure 3a and 3b show applications of a disinfection system according to the invention. In figure 3a, the disinfection unit 30, comparable to the unit from figure 1, is mounted on the ceiling 31. Through the lamellae, the UV radiation 32 is projected sideways, for disinfecting the air in the upper part of the room. The converted UV radiation is emitted as visible light 33, which is projected downwards, where it is most useful to persons 34 in the room. As the UV-light is projected in the plane of the ceiling, exposure of the persons 34 to UV-light is minimized.

Figure 3b shows an alternative embodiment, wherein the disinfection unit 40 is mounted to the wall 41. UV radiation 42 from the unit 40 is directed upwards and downwards along the wall, while the converted light 43, which is visible, is directed into the room, where persons 44 in the room benefit the most .In this case care should be taken that the unit is mounted high enough to avoid people looking directly in the UV radiation. In an alternative embodiment, the UV radiation 42 is only directed upwards along the wall 41 (not shown in Fig. 3b).