EP4146292A2 - Device and method for disinfecting a fluid flow via uv-c radiation - Google Patents

Abstract

A device for the disinfection of a volume containing a gaseous fluid, comprising a hollow body (2) having a reflective inner surface (7), an inlet opening (3) and an outlet opening (4), and one or more sources (5) of UV-C radiation placed inside the body (2); the body (2) defines an optical cavity generating a multiplicative effect of the illumination intensity due to multiple reflections inside the body (2). The device can be used in assisted breathing or ventilation systems for disinfecting the air exhaled by a patient.

Description

"DEVICE AND METHOD FOR DISINFECTING A FLUID FLOW VIA UV-C

RADIATION"

CROSS-REFERENCE TO RELATED APPLICATIONS This patent application claims priority from Italian patent application no. 102020000010378 filed on 8/5/2020, the entire disclosure of which is incorporated herein by reference.

TECHNICAL FIELD The present invention relates to a device and to a method for disinfecting a fluid flow via UV-C radiation. The invention has its preferred forms of application in the disinfection of the air exhaled by a patient subjected to non-invasive assisted breathing and of air flows in ducts of air-conditioning or ventilation systems in general.

BACKGROUND ART

In this period of emergency brought about by the Covid- 19 pandemic, the disinfection of environments is taking on a fundamental role due to the high infectiousness. Tested techniques using germicides, UV radiation, etc. can be used in the environments.

The treatment of the air coming directly from a patient to whom a respiratory aid has been applied is more critical, for example in confined environments such as an ambulance or a room prepared in emergency regime or also in case of home treatment. In these cases, the air is not always treated before being re-emitted into the environment and the only solution for avoiding entering into contact with pathogenic germs consists in equipping people with individual protection devices (IPDs). This entails non-negligible risks in case of an incorrect use of the IPDs and for their disposal.

Also in the event that the air is treated before being re-emitted into the environment, for example via electrostatic or membrane filters, the filters must be changed after a few hours of operation, with considerable management and disposal costs, and with the further difficulty of following strict protocols for maintaining the required level of hygiene. The disinfecting power of UV radiation is well known; however, the UV disinfection systems known for being effective, in particular with wavelengths operating in the so-called UVC band (between 250 and 280 nm), require a dosage of several mJ/cm² (variable depending on the microorganism considered) and obtainable by using relatively high power sources and/or a relatively long stay of the air in a confined area subjected to the radiation.

It follows that the known systems have significant application limits. For example, they are not suitable for the provision of compact, portable solutions and/or easily applicable to existing assisted breathing systems, or for the disinfection of high flow rate air flows.

DISCLOSURE OF INVENTION

The object of the present invention is the manufacturing of a device for the disinfection of a fluid flow that is devoid of the drawbacks of the above specified known devices.

The above-mentioned object is achieved by means of a device according to claim 1.

BRIEF DESCRIPTION OF THE DRAWINGS For a better understanding of the present invention, some preferred embodiments are described in the following with reference to the accompanying drawings, wherein:

Figure 1 is a schematic section of a disinfection device according to the invention; Figure 2 is a scheme that illustrates an assisted breathing system provided with a device according to the present invention;

Figure 3 is a perspective and schematic view of a further embodiment of the device according to the present invention; Figure 4 is a schematic section of a further embodiment of a device according to the present invention;

Figures 5a, 5b and 5c are perspective views of further embodiments of the present invention;

Figure 6 is a perspective and schematic view of a further embodiment of the device according to the present invention; and

Figure 7 is a partial section according to the line VII-VII of Figure 6.

BEST MODE FOR CARRYING OUT THE INVENTION With reference to Figure 1, an embodiment example of a disinfection device 1 according to the present invention is schematically illustrated.

The device 1 comprises a hollow body 2 provided with an inlet opening 3, an outlet opening 4 and one or more sources 5 of UV-C radiation, having a wavelength preferably between

250-280nm, housed inside the hollow body 2.

The sources 5 can consist of LEDs.

The sources 5 can be powered by a battery 6, suitably built into the device 1. The hollow body 2 has a reflective inner surface 7

(specular or diffusing), consisting, for example, of an aluminum coating (reflectance p=0.92), and therefore behaves like an optical cavity that generates a multiplicative effect of the illumination intensity due to the multiple reflections inside the body. For the purposes of the present invention, the term "reflective" is used to indicate a surface or coating having a reflectance of at least 0.8 (i.e. 80%).

This multiplicative effect increases as the reflectance of the internal coating increases. Other materials suitable for constituting a reflective coating can be metallic reflective films (with a specular or diffusing surface) deposited under vacuum or using other methods, or reflective films deposited under vacuum with a multi-layered structure containing dielectric materials (for example SiCh) to obtain a high reflectivity in the UV-C region and simultaneously filter other bands and protect the surface with respect to reflectivity losses (for example from oxidation). The hollow body can also consist of a sheet made of metal (for example aluminum), having a reflective inner surface (specular or diffusing), suitably worked so that it assumes the optomechanical configuration of the hollow body 2.

The inlet opening 3 and the outlet opening 4 in the illustrated example are arranged at the same axial end (base) of the hollow body 2 in order to maximize the time of stay of the gas inside the device, and thus minimize the dimensions of said device.

The volume of contaminated gas has an extremely low absorption, of the order of magnitude of 1%, and thus does not reduce the light intensity by significant amounts. The geometry and the characteristics of the device illustrated by way of example in Figure 1 are: cylinder diameter: 80mm; cylinder height: 80mm; inlet/outlet openings: diameter 22mm; inner coating: aluminum; 2 25mW UV-C LEDs; wavelength: 254 nm.

The total light power calculated by means of numerical simulation methods is approximately equal to 268 mW. Assuming a flow rate of 0.51/s typical of a patient connected to an assisted breathing apparatus, the exhaled flow passes through the device in approximately 1.6 s: the resulting illumination dosage is equal to 6.7 mJ/cm², which is sufficient for the disinfection of the gas with respect to the presence of viruses similar, for example, to SARS-COV- 2, based on recent published estimates.

A similar result can be obtained with a row of six SMD LEDs having a power of 9mW. This yields a total light power of 280 mJ corresponding to a dosage of 7 mJ/cm². With an opaque or transparent hollow body under the same conditions, a dosage of 0.54 mJ/cm² would be obtained, which is not sufficient for the complete inactivation of the pathogenic agents present in the flow.

In Figure 2, reference numeral 11 indicates, as a whole, a non-invasive assisted ventilation system.

The system essentially comprises, in a known manner: a ventilator device 12, having the purpose of producing an air flow or possibly a gaseous mixture of air enriched with oxygen (in the following, for the sake of brevity,

"the gas"); a gas-conditioning device 13 having the purpose of controlling the temperature and humidity of the gas; and an interface device 14, having the purpose of conveying the gas to the patient's external respiratory airways. The interface device 14 can consist of a simple mask, a nasal tube, a face mask, or a helmet. The type of interface essentially depends on the administered air flow.

As schematised in Figure 2, in some cases and mostly in the low flow systems (for example, in the masks used in ambulances or in the devices left at the home of people affected by respiratory problems), the exhaled air is re emitted into the environment through holes 15 in said mask. According to the present invention, before being re-emitted into the environment, the air is made to pass through a disinfection device 1 manufactured according to the invention .

Without prejudice to the general principle of the above- described optical cavity, the device 1 comprises coupling means coupled to the used interface device which differ depending on the type of such device, as described in the following using identical numbers for identical components or corresponding to components already described.

For example, in the case of the mask with holes of Figure 2, the device 1 can be manufactured having a box- shaped body 2 as illustrated in Figure 3. The body 2 is shaped to adhere along the perimeter of the mask, to which it can be fixed along an open back edge 20 by means of adhesive, Velcro® or a suction-cup system not illustrated. Inside the body 2, which in use extends in a protruding manner from the front of the mask, the UV-C source 4 is housed, which preferably extends downwards from an upper wall 21 of said body (in use, in front of the nose of the patient). The body 2 has a lower slot 22 through which the duct for supplying gas to the mask can pass. The body 2 is expediently provided with a front hole 23 through which the disinfected air outflows, and can also comprise possible shields for avoiding light returns towards the patient.

Figure 4 illustrates a disinfection device 1 similar to the one described in Figure 1, from which it differs essentially by the fact that the inlet opening 3 and the outlet opening 4 are arranged on axially opposite sides of the body 2. In this case, the body 2 consists of a cylindrical barrel 30, inside which the sources 5 are fixed, and of a pair of end flanges 31, 32 fixed at the opposite ends of the barrel 30 and defining the respective openings 3 and 4. The device 1 of Figure 4 further comprises a coupling connector for coupling to the interface device 14 as illustrated in Figure 5a, 5b or 5c.

In case the interface device is a mask 14 provided with an outlet hole 16, as illustrated in Figure 5a, the device 1 can comprise a connector 17 connected to the hole 16 and provided with an adhesive terminal flange 18 designed to be fixed around the hole 16.

The connector 17 can be elbow (Fig. 5a) or rectilinear (Fig. 5b). Alternatively, the connector 17 can be flexible so as to allow any orientation of the device 1.

Figure 5c illustrates a solution wherein the mask 14 comprises a plurality of small-sized holes 19 as outlet opening. In this case, the flange 18 must be dimensioned so as to surround said holes.

In case of a mask with a single outlet duct, a bag shaped device 1 as illustrated in Figures 6 and 7 can be used. The device 1 comprises, in this case, a substantially rigid top cap 24, provided with an inlet opening 25 provided with a seal 26 designed to be coupled to the outlet duct of the mask.

The cap 24 also houses the UVC source 4.

Fixed to the cap 24 is a bag-shaped body 2 coated internally with a reflecting material. As it is deformable and devoid of a shape of its own, the body 2 reduces the problems of bulk associated with a rigid body. The body 2 is provided with a bottom outlet opening for the air, not illustrated.

A bag-shaped device of the aforementioned type can be used also in the case of a mask with holes, replacing the cap 24 with a suitable open interface designed to fit the profile of the mask around the holes of the same.

Examining the characteristics of the devices 1 manufactured according to the present invention, the advantages that the latter allows obtaining are evident.

The multiplicative effect of the light intensity due to the reflective coating of the body 2 allows using the disinfection via UV-C radiation in contexts that require a miniaturization and a portability of the system. The direct connection of the disinfection device to the interface device that interfaces with the patient allows simplifying the apparatus and preventing modifications to existing apparatuses .

The devices of Figures 3 to 7 are thus suitable for being used as retrofits of existing apparatuses.

Finally, it is evident that modifications and variants can be made to the illustrated devices 1 without departing from the scope of protection defined by the claims.

Claims

1. A device for the disinfection of a fluid, comprising a hollow body (2) having a reflective inner surface (7), at least one inlet opening (3) and at least one outlet opening (4), and at least one source (5) of UV-C radiation placed inside the body (2), said body (2) defining an optical cavity generating a multiplicative effect of the illumination intensity due to multiple reflections inside the body (2), the device (1) comprising coupling means (17) for the direct connection to a respiratory interface device (14) in an assisted breathing system.

2. A device as claimed in claim 1, wherein the reflectance of the internal surface of the body is at least 0.8 (80%).

3. A device as claimed in claim 1 or 2, wherein the reflective inner surface (7) consists of a reflective coating.

4. A device as claimed in claim 3, wherein the coating includes a material selected in the group comprising a thick aluminum film, a thin aluminum film deposited under vacuum, a thin multi-layer film possibly containing dielectric materials to optimize the reflectance response.

5. A device as claimed in claim 1 or 2, wherein the body is replaced by a material with an optically specular inner surface in the UV-C band.

6. A device as claimed in any of the above claims, wherein at least one source (5) consists of an LED.

7. A device as claimed in any of the above claims, wherein the UV-C radiation has a wavelength between 250 and 280 nm.

8. A device as claimed in any of the above claims, comprising a plurality of LEDs with a total power not exceeding 60 mW, the body being configured to produce a dosage of more than 5 mJ/cm2.

9. A device as claimed in any of the above claims, including a built-in power supply battery (6).

10. A device as claimed in any of the above claims, wherein the coupling means comprise an adhesive connector (17).

11. A device as claimed in any of the above claims, wherein the body (2) is tubular.

12. A device as claimed in one of claims 1 to 10, wherein the body (2) is in the shape of a box configured to fit a mask of an assisted breathing system.

13. A device as claimed in one of claims 1 to 10, wherein the body (2) is in the shape of a deformable bag.

14. An assisted breathing system comprising a ventilator (12), an interface device (14) configured to convey a flow produced by the ventilator (12) to the patient's external respiratory airways and a disinfection device (1) as claimed in any of claims 10 to 13, connected to the interface device (14) to intercept the air exhaled by the patient.

15. A system as claimed in claim 14, wherein the connector of the disinfection device (1) is connected to an opening (15) of the interface device (14).

16. A system as claimed in claim 14 or 15, wherein the disinfection device is connected to a return duct (19) from the interface device (14) to the ventilator (12).