WO2022049535A1

WO2022049535A1 - Filter sanitizing device applicable to personal respiratory protective masks, and protective mask comprising said sanitizing device

Info

Publication number: WO2022049535A1
Application number: PCT/IB2021/058061
Authority: WO
Inventors: Gennaro BUFALO; Luigi AMBROSONE
Original assignee: Universita' Degli Studi Del Molise
Priority date: 2020-09-04
Filing date: 2021-09-03
Publication date: 2022-03-10
Also published as: EP4208210A1

Abstract

A device for sanitizing surfaces and materials by emitting UV rays is described, which is usable in a stand-alone mode and also applicable to protective masks for sanitizing filters or other parts of the aforesaid masks which require disinfection from pathogens. A protective mask provided with the aforesaid device is also described.

Description

FILTER SANITIZING DEVICE APPLICABLE TO PERSONAL RESPIRATORY PROTECTIVE MASKS, AND PROTECTIVE MASK COMPRISING SAID SANITIZING DEVICE

FIELD OF THE INVENTION

The subject of present description belongs to the technical field of personal protective equipment (PPE), used to protect the health and safety of workers and people in general. In particular, the present description relates to the field of respiratory PPE adapted to avoid or limit the ingress of pathogens or allergenic elements into the airways.

BACKGROUND ART

Any tool, object, or garment which can be utilized by a user to reduce specific or general risks or potential incidents is a piece of Personal protective equipment (PPE) (Cf. for example, the Italian Consolidated Law on Health and Safety at Work or Italian Legislative Decree no. 81/08). From this definition, it is apparent that (disposable) surgical masks, having neither a sealing edge on the face nor a specific filtering system for solid and/or liquid aerosols, cannot be considered PPE.

Indeed, disposable surgical masks are medical devices for protecting patients under specific conditions and do not protect personnel wearing them. These disposable surgical masks can consist of two or three layers of non-woven polyester or polypropylene fibers. Their outward filtering capacity (for bacteria) is greater than 95%, while their inward filtering capacity is less than 20% due to the poor fit on the wearer's face.

On the other hand, devices which reduce the introduction of hazardous substances or elements by inhalation are true respiratory PPE. Although the latter devices are used in industries to protect workers from gaseous substances through filtration, they are also used in other fields, and in particular, in the health care domain, to protect workers from bacteria, viruses, and pathogens.

These devices, referred to as filtering facepieces, are generally made of polypropylene or polycarbonate fiber layers joined together by ultrasonic welding. Based on their filtering power, these devices are classified as FFP1 , FFP2, and FFP1 devices allow 72% filtration from the outside to the operator and vice versa, from the operator to the outside. FFP2 devices allow 92% filtering capacity in both directions, however, the size of the filter pores is larger than the size of the virus, so they block particles by electrostatic effect and even viruses which do not travel as aerosols become trapped. FFP3 devices allow for both inward and outward filtration with 98% efficiency. Such devices protect almost completely by having smaller filtering pores which are comparable in size to those of the virus. FFP3 devices exhibit similar performance to surgical masks relative to outward filtration.

However, they have the disadvantage that the exhaled air accumulates in these types of devices, thus making breathing more laborious, which is why they are not always tolerated by the wearer.

If the filtering facepiece covers the entire face, it is referred to as a full-face mask; instead, if it covers only the nose, mouth, and chin, it is classified as a half mask.

FFP2 and FFP3 devices are generally provided with exhalation valves and replaceable filters to retain pollutants or pathogens. Half masks are often made of elastic/silicone material because they cover only a small portion of the face to increase their fit to the face. Furthermore, the full-face masks and half masks are generally provided with a single, sliding elastic band, preferably of double thickness to avoid breakage in use, with attachment to the structure of the device.

Some examples of full-face masks and half masks of the prior art, provided with compact, non-compact, or removable filter packs which may be either replaceable or not replaceable and either provided or not provided with protective grids, are shown in Fig. 1 accompanying the present application.

The personal protective equipment described can generally be reusable after appropriate sanitization. One of the known methods for effective sanitization from pathogens is based on irradiation using ultraviolet (UV) rays.

UV radiation is the part of the electromagnetic spectrum falling between x-rays and visible light. Based on its physiological effects, UV radiation is divided into three main regions. UVA 315-400 nm, UVB 315-280 nm and UVC 280-100 nm. The ability of UV rays to penetrate biological tissues increases as the wavelength decreases, so that UVC rays are the most effective at inactivating bacteria and viruses and have a greater germicidal effect. In the specific case of viruses, germicidal ultraviolet UVC irradiation has proven to be highly effective. This effectiveness is due to the strong absorption of DNA in the ultraviolet wavelength range. Indeed, the double helix structure of DNA has the pyrimidine molecule, which exhibits a strong absorption at 260 nm, among its constituent bases. When the DNA molecule of a virus is irradiated with UVC rays, the pyrimidine bases absorb the radiation thus becoming more energetic. In this energized state, the pyrimidine molecules dimerize, irreversibly distorting the DNA double helix, which is thus no longer able to replicate inactivating and losing its infectivity.

In order to improve the personal protective systems described above, it would be desirable to make them self-disinfecting, to ensure their effectiveness in use, and continue this self-disinfection even after their use and generally during the time for which they are not used. This could advantageously avoid specific sanitizing procedures after the device is used.

Therefore, it is an object of the present invention to introduce a device which is applicable to full-face masks or half masks of the prior art and also usable in a standalone mode and adapted to sanitize filters or other parts of said full-face masks and half masks which require disinfection from pathogens.

The present invention further aims at introducing a full-face mask or half mask capable of solving the technical problems present in the present prior art, including those mentioned above, and improving the currently available full-face masks and half masks.

DETAILED DESCRIPTION OF THE INVENTION

The device of the present description, in a preferred embodiment, comprises sanitizing means based on the emission of ultraviolet rays such as, for example, ultraviolet rays of the UVC type. Said device is configured to be applied to a full-face mask or half mask for personal respiratory protection and to be operable both when the full-face mask or half mask is worn and in use and when it is not.

A preferred embodiment of the device according to the present description thus comprises: - a support adapted to accommodate:

- at least one UV LED for generating UV radiation adapted for sterilization, said UV radiation being preferably of the UVC type;

- support means for said at least one UV LED;

- appropriate power supply means for said at least one UV LED;

- a control and drive system for managing said at least one UV LED and said power supply system;

- at least one communication interface for data and power, such as a USB port.

In a preferred embodiment, said support is further adapted to accommodate:

- a user interface configured to provide the user with information about the operational status of the device.

This user interface may advantageously consist of at least one LED emitting colored light, preferably iridescent light. Said at least one LED emitting colored light could, for example, be turned on when said UV LED is on so as to warn the user. Iridescent LEDs can easily be used to set the signaling of different events by means of different colors, by driving the LED operated by said control and drive system.

Said appropriate power supply system may simply comprise a power supply circuit connecting said communication interface - e.g., a USB port - to said at least one UV LED, or a power supply circuit further comprising a battery charger circuit - connected to said communication interface - and a rechargeable battery, as widely known from the prior art.

Advantageously, a preferred embodiment of the device according to the present description further comprises a filter holder block adapted to accommodate a filter which may be of various types, according to the type of application: mechanical filters with fabric sieves, fiber, granules, etc. may be used for protection from dust and aerosols, while activated carbon filters or combinations of the above filters may be used for protection from gases and vapors. Furthermore, said filter holder block serves the function of associating the filter with the sanitizing UV LED(s). In a preferred embodiment, the filter holder block is adapted to maintain the filter in an optimal position both to perform its function and to be effectively irradiated by said at least one UV LED. In a preferred embodiment, said support means for said at least one UV LED are advantageously adapted to accommodate said at least one UV LED in a user-orientable manner.

In another preferred embodiment of the device according to the present description, said support may comprise a protective grid. Said UV LED can advantageously be accommodated in said protective grid or within a dedicated support, separate from said grid.

If the device according to the present description is used for short periods, the sanitizing UV LED(s) may be left off in use and then turned on to sanitize the device once it is stored after use. However, in the case of long-term use of the device, in order to ensure the filtering effectiveness over time and avoid, for example, the accumulation of pathogens, the sanitizing UV LEDs can be kept on even while the device is worn.

The battery will be appropriately sized to allow said sanitizing UV LEDs to be powered for a time sufficient for the type of work to be performed by the operator wearing the device, and in general for the required sanitizing time.

Advantageously, the sanitizing device of the invention can be made so as to be easily applied to existing full-face masks and half masks - for example to replace the original filter boxes - and also be employed in a stand-alone mode as a practical element for active surface sanitization. Furthermore, by employing UV LEDs capable of emitting appropriate wavelengths, - such as in the range of 280-400 nm - said sanitizing device can also be advantageously used for "forensic" applications, such as the detection of stains and substances not directly visible to the naked eye. The sanitizing device and the personal protective device according to the present invention thus allow important improvements in terms of both flexibility and safety of use, compared to similar devices of the prior art, by introducing a full-face mask and a half mask comprising sanitizing means which allow a continued and repeated use thereof while always maintaining the nominal level of operating effectiveness and level of safety.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages of the invention will become apparent upon reading the following detailed description, provided by way of non-limiting example, with the aid of the figures shown on the accompanying drawings, in which: Fig. 1 shows examples of masks provided with filters of the prior art;

Fig. 2 shows an exploded perspective view of a preferred embodiment of the device according to the present invention associated with a personal protective mask;

Fig. 3 shows a perspective view of a detail of the preferred embodiment of the device according to the present invention shown in Fig. 2;

Fig. 4 shows a perspective view of a preferred embodiment of the device according to the present invention in which the position of the LEDs on the side edge of the support can be seen;

Fig. 5 shows a perspective view of a preferred embodiment of the device according to the present invention in which the LEDs are provided with a reflector;

Fig. 6 shows a perspective view of a preferred embodiment of the device according to the present invention in which the LEDs are provided with an orientable reflector; Fig. 7 shows a perspective view of a preferred embodiment of the device according to the present invention provided with means for the application to filter boxes;

Fig. 8 shows a perspective view of the preferred embodiment of the device according to the present invention shown in Fig. 7, applied to a filter pack of a protective mask;

Fig. 9 shows a perspective view of a variant of the preferred embodiment of the device according to the present invention shown in Fig. 7.

Fig. 10 shows a perspective view of another variant of the preferred embodiment of the device according to the present invention shown in Fig. 7.

The following description of exemplary embodiments refers to the accompanying drawings. The same reference numbers in the various drawings identify the same elements or similar elements. The following detailed description does not limit the invention. The scope of the invention is defined by the appended claims.

DETAILED DESCRIPTION OF THE INVENTION

The term mask is used in the present description to indicate both proper masks adapted to cover the entire face and masks adapted to cover only the user's nose, mouth, and chin, commonly referred to as half masks.

The present description relates to a sanitizing device which is applicable to a personal respiratory protective mask, and to a protective mask comprising said sanitizing device. Said sanitizing device comprises sanitizing and disinfecting means based on the application of UV. Furthermore, said sanitizing and disinfection means allow sterilizing the parts of the device (in particular the filter and surrounding parts) both during the use of said device by the user and when the device is not being worn, to sanitize it for its next use.

A preferred embodiment of the device according to the present description comprises:

- a support adapted to accommodate:

- support means for said at least one UV LED;

- appropriate power supply means for said at least one UV LED;

- at least one communication interface for data and power, such as a USB port.

In a preferred embodiment, said support is further adapted to accommodate:

- a user interface, connected to said control and drive system, configured to provide the user with information on the operational status of the device.

Said at least one UV LED is preferably - but not exclusively - adapted to emit UVC- type UV radiation.

Said user interface can advantageously be made by at least one auxiliary LED emitting colored light in the visible field, preferably iridescent light. Said at least one LED emitting colored light could, for example, be turned on when said UV LED is on so as to warn the user that sterilization is in progress. Iridescent LEDs can easily be used to set the signaling of different events by means of different colors, by driving the LED operated by said control and drive system. Other auxiliary LEDs emitting in the visible field can be used in the immediate vicinity of the UV LEDs to enable the correct positioning of the LED radiation field to be verified after the device has been assembled.

In other preferred embodiments, the user interface may comprise at least one key and a miniaturized display for setting the programmable functions more easily. In another preferred embodiment of the device according to the present description, said support may comprise a protective grid. Said UV LED can advantageously be accommodated in said protective grid or within a dedicated LED support, separate from said grid, and can be oriented by the user.

Advantageously, the device according to the present description may be provided with a rechargeable battery - and associated power circuitry - appropriately sized to ensure that the device is operational for as long as necessary.

The electrical and electronic circuitries comprising said power supply system and said control and drive system are appropriately miniaturized and distributed to facilitate accommodating them inside the device described, and in particular inside said support.

A preferred embodiment of the device according to the present description further comprises a filter holder block adapted to accommodate a filter which may be of various types, according to the type of application: mechanical filters with fabric sieves, fiber, granules, etc. may be used for protection from dust and aerosols, while activated carbon filters or combinations of the above filters may be used for protection from gases and vapors. Furthermore, said filter holder block serves the function of associating the filter with the sanitizing UV LED(s). In a preferred embodiment, the filter holder block is adapted to maintain the filter in an optimal position both to perform its function and to be effectively irradiated by said at least one UV LED. In a preferred embodiment, said support means for said at least one UV LED 13 are advantageously adapted to accommodate said at least one UV LED in a user-orientable manner.

A preferred embodiment of the sanitizing device according to the present description is shown with reference to accompanying Fig. 2 and Fig. 3. This preferred embodiment provides that said support comprises a protective grid 16 which also acts as a support for said UV LED 13 so that it appropriately faces the filter to be sanitized. Alternatively, the UV LED(s) can be placed on the side of the support 15, in appropriate housings, as shown in Fig. 4, and can be provided with an appropriate reflector (as in Fig. 5 and Fig. 6) and also be orientable as shown in Fig. 6.

In the preferred embodiment of Fig. 7, said support 15 comprises a central portion adapted to accommodate at least one UV LED, preferably in a user-orientable manner, and a plurality of arms (three in the example of Fig. 7, Fig. 8, Fig. 9, and Fig. 10), each comprising two or more telescopic parts 24, 25 sliding into one another and connected by appropriate elastic means, e.g. a tension spring, adapted to oppose the extraction of the inner telescopic part 25 from the outer telescopic part 24. Appropriate means for locking the mutual position between the aforesaid telescopic parts 24, 25 can be advantageously employed, e.g., based on a rack and pinion coupling. The ends of the inner telescopic parts 25 of said arms are provided with fixing means to the filter pack of a protective mask, which fixing means can be made by appropriate terminals 26. Said terminals 26 are arranged at the end of said inner telescopic part 25 and extend in a direction substantially orthogonal thereto. Obviously, other suitable fixing means can be chosen appropriately, according to the type of support 15 or filter pack to be sanitized. For example, said arms can be segmented and joined by cylindrical or spherical joints, or made of semi-rigid and flexible materials. Furthermore, said terminals 26 can be fitted with adhesive, magnetic, or interlocking hooks, etc.

Finally, said support 15 comprises an electrical connector 14 for connecting the electrical power supply circuit of the UV LED and any drive and control signals.

Appropriate external power means - for example an electronic switching power supply - can be connected to said power supply circuit through the connector 14. Advantageously, a preferred embodiment of the device according to the present description comprises a rechargeable battery, preferably of the lithium-ion type, connected to said at least one UV LED and to said connector 14 through an appropriate electrical circuit in one of the known manners which are usual in the art. Said control and drive system preferably comprises a programmable electronic circuit, implemented in one of the known manners which are usual in the art, having the function of managing the operation of said UV LED in cooperation with said user interface, and providing the user with information on the status of the device. The main programmable functions include the following: programmable timer for adjusting on/off and irradiation times; detection and information on the state of charge and recharge of the battery/batteries; detection and information on the power status of the UV LED(s); self-diagnosis regarding the correct functioning of the electronic components of the device.

Further variants of the device according to this description can include accessories to facilitate the application thereof to the mask or filter pack to be sanitized. In Fig. 9, said terminals 26 are of the telescopic type to facilitate the use with bulky filter packs or entire masks. In Fig. 10, the device according to the present description comprises a pedestal 27 comprising telescopic rods 28 adapted to engage said terminals 26. The pedestal 27 can advantageously provide a support base for the mask to be sanitized while avoiding contact with potentially contaminated surfaces. The device can be advantageously placed on the material to be sanitized or disinfected by operating the UV LED(s) and holding it in place for the time required to complete the operation. The small size thereof allows it to be easily used even in situations in which the material to be sanitized is not easily accessible. Typical uses may concern both surface sanitization and fabric sanitization, in particular the device described can be used to sanitize filters of masks comprising replaceable filter packs.

Advantageously, the described device can be made so as to integrate a filter block therein, which is thus self-sanitized. In this preferred variant, the described device can replace filter packs of masks provided therewith and also enable the retrofitting of masks which are not provided with filter packs.

A preferred application of the sanitizing device according to the present invention, which can be associated with a protective mask 10, is shown in accompanying Fig. 2. The mask is adapted to cover the user's nose and mouth and comprises a cup 11 made of a rigid or semi-rigid material - e.g., plastic material, rubber, fiber, composite material, etc. - with an edge which may advantageously comprise elastic or silicone material to increase the fit on the face.

On the front part, in a zone corresponding to the mouth and nose of the user when worn, the mask has the sanitizing device described, in the version having a support 15 further comprising a filter holder block adapted to accommodate a filter 12, which can be replaced and sanitized/sterilized by UV rays, as well as at least one UV LED 13 adapted to emit UV rays, preferably of C type. Said filter 12 can be made, for example, of a "non-woven fabric" of polypropylene, but other filters of types known from the prior art can also be used, choosing the most suitable type according to the desired protective effectiveness. Dust and aerosol protection filters which perform mechanical filtering by means of cloth, fiber, granule sieves, etc., for example, or gas and vapor protection filters (e.g., activated carbon filters) or combinations thereof can be used.

In any case, a higher filtering power corresponds to increased respiratory resistance, and thus the surface of the filter will be appropriately sized depending on the applications.

Said device, in a preferred embodiment, comprises a support 15 adapted to engage a corresponding hole on said cup 11 and comprising, in turn, a protective grid 16 and a filter holder block which includes a filter 12, a first ring nut 17 for fixing the support 15 to the cup 11 , and a second ring nut 18 for fixing the filter 12 to the support 15.

The protective grid 16 may advantageously comprise at least one housing adapted to accommodate at least one LED 13 and a connector 19, comprising electrical contacts connected to the electrical terminals of said at least one LED 13, and adapted to connect to the electrical power supply circuit the electrical terminals of which are connected to said connector 14 when the device is assembled. In a preferred embodiment, said protective grid 16 is advantageously adapted to accommodate said at least one UV LED in a user-orientable manner.

The fixing between the various parts of said device can be achieved by means of threads, joints, bayonet joints, hinges, or even by gluing.

Furthermore, all parts of said device, shown in detail in accompanying Fig. 2, can advantageously be made of a plastic material, rubber, fiber, a composite material, or combinations of the aforesaid materials.

Furthermore, the surfaces of the parts of the device exposed to UV radiation may be made of UV-resistant material, such as a UV-reflecting material, for example.

In a preferred embodiment of the mask 10 comprising the sanitizing device according to the present description, one or more through connectors 21 can be provided on the outer surface of the cup 11 to make it easier to connect an electrical power cable 22 to the connector 14 of the support 15. In this case, an appropriate electrical cable 20 is provided for the connection of a port of the through connector 21 with the connector 14 of the support 15.

The chosen UV LED(s) preferably emit wavelengths between 100 and 300 nm. The LEDs characterizing the aforesaid wavelengths are adapted to perform functions of disinfection/sterilization and reduction of colonies of bacteria, viruses, fungi, etc.. Other parameters to be chosen regarding the LED(s) used are the irradiation time and the distance from the surface of the filter to be irradiated, connected to the so- called "viewing" angle which indicates the opening of the LED irradiation cone.

In an exemplary embodiment of the device according to the present description, said at least one LED 13 has a power of about 50 mW, a viewing angle of about 150°, and is accommodated at a distance of about 8 mm from the filter 12 which has a total surface area of slightly less than 20 cm². Given the distance from the filter 12 and the viewing angle of the LED 13, it results that the radiating surface area is just under 28 cm² and thus sufficient to cover the entire surface of the filter 12. With the aforesaid configuration, an irradiation of the filter 12 is obtained so as to convey a dose of UVC rays equal to about 3057 J/m², considered lethal for the viruses responsible for SARS and COVID-19, for example.

A further preferred embodiment of the device according to the present description includes the possibility of varying the height of the position of the UV LED(s) with respect to the filter. To this end, said protective grid 16 can be made with a diameter such that it can slide into the support 15. The sliding could be adjusted, for example, by a thread made on the outer side of the protective grid 16, adapted to engage another thread made on the inner side of the support 15.

Advantageously, the described sanitizing device can also be used for retrofitting existing masks or used in stand-alone mode as a practical element of active surface sanitization.

When employed for retrofitting existing masks, the described sanitizing device can advantageously be made of appropriate size and shape to adapt it to various needs. The described device can thus be used with masks with removable and replaceable filter packs, masks with filters provided with removable external grids, or masks provided with filters having a non-removable external grid. The sanitizing device according to the present description can also be used on masks provided with an exhalation valve, taking care to position the sanitizing device so as to radiate the valve as well.

Finally, the device according to the present description can also be successfully used in association with electro-respirators provided with one or more filters, in a manner similar to those described above.

Claims

1 . A sanitizing device comprising a support (15, 16) adapted to accommodate: at least one UV LED (13) for generating UV radiation adapted for sterilization; support means for said at least one UV LED (13); power supply means for said at least one UV LED (13); control and drive means for managing said at least one UV LED (13) and said power supply system; at least one communication and distribution interface for data and power supply associated with a connector (14).

2. A device according to claim 1 , characterized in that said support (15) comprises a user interface connected to said control and drive means and configured to provide information on the operating status of the device and/or to receive settings from the user.

3. A device according to claim 2, characterized in that said user interface comprises at least one auxiliary LED and/or at least one button and a display.

4. A device according to one or more of the claims from 1 to 3, characterized in that said power supply means comprise a rechargeable battery.

5. A device according to one or more of the claims from 1 to 4, characterized in that it comprises a protective grid (16).

6. A device according to claim 5, characterized in that said protective grid is adapted to accommodate said at least one UV LED (13).

7. A device according to one or more of the claims from 1 to 6, characterized in that said support means for said at least one UV LED (13) comprise a central part adapted to accommodate said at least one UV LED (13) and a plurality of arms each comprising two telescopic parts (24, 25) sliding into each other and connected by appropriate elastic means, the ends of the inner telescopic parts (25) of said arms being provided with means to be fixed to the support (15).

8. A device according to one or more of the claims from 1 to 7, characterized in that said support (15) further comprises a filter holder block adapted to accommodate a filter (12), which can be replaced and sanitized by UV rays emitted by said at least one UV LED (13).

9. A device according to one or more of the claims from 1 to 8, characterized in that said filter holder block includes a filter (12), a first ring nut (17) for fixing the support (15) to the cup (1 1 ) of a protective mask (10), and a second ring nut (18) for fixing said filter (12) to the support (15).

10. A protective mask (10) comprising a cup (11 ) made of a rigid or semi-rigid material and a sanitizing device according to one or more of the claims from 8 to 9, arranged in a zone of said cup (11 ) corresponding to the user's mouth and/or nose when the protective mask (10) is worn.