Protective Air Filtration Device

Abstract

The protective air filtering device (1) comprises a fastening structure (3) for fastening to a user's head, a visor (2) associated with the fastening structure (3), a hood (4) fixed to the fastening structure (3) and defining a closed chamber (7), a rear air inlet (5) with an inlet filter (5.1), an air outlet (6) and a fan (8) for generating an air flow from the air inlet (5.1) through an upper air duct (9) through the front of the closed chamber (7) to the air outlet. The air outlet (6) is arranged on one side and comprises an outlet filter (6.1), a side frame (6.2) and a side cover (6.3). The outlet filter (6.1) is fixed between the side frame (6.2) and the side cover (6.3).

Description

[Technical field]

[0001] FIELD OF THEINVENTION This invention relates to protective air filtration devices of the type known as personal protective equipment (PPE). [Background technology]

[0002] Today, personal protective equipment (PPE) is commonly used by workers in various fields to protect themselves from one or more risks that may threaten their safety or health.

[0003] One of these fields is the medical field, where workers (doctors, nurses, assistants, etc.) come into direct contact with sick patients, who may transmit the disease to medical workers or other patients through infectious materials (airborne materials, body fluids, etc.). Furthermore, medical workers themselves may become ill (e.g. in the home environment) and infect their patients.

[0004] To prevent these risks, one of the most commonly used PPE items by healthcare workers is a mask (e.g. known as a surgical mask), which consists of a cloth or paper made of a barrier material that is placed over the nose and mouth and fastened to the head with a band or strap to prevent the transfer of infectious materials from the patient to the user or vice versa.

[0005] These masks have the significant disadvantage of not completely isolating the user, leaving the user at risk of contracting disease from contact with infectious material (e.g., through the eyes, skin, etc.), as well as the user's own infectious material (exhaled air, sweat, etc.) potentially endangering the patient's health.

[0006] In addition, other PPEs are often used that cover most of the user's face, commonly called full face masks. These full face masks are fastened to the head by straps and include a transparent visor that covers the user's face and isolates it from the outside. The full face masks usually include holes for air inlet and outlet at the bottom, which include replaceable filters for filtering the air passing through the holes.

[0007] The main drawback of this type of full-face mask is that the visor often fogs up due to condensation from the user's breath, making it difficult to carry out the task. This visor fogging, if it occurs during surgery for example, can lead to very dangerous situations, where any mistake could put the patient's life at risk.

[0008] Another drawback of these full face masks is that they do not isolate the user's entire head, so the user may still be exposed to infectious agents that may enter the body through the skin, or may expose the patient to the user's infectious agents, posing a health risk.

[0009] Additionally, it is known to use PPE, commonly referred to as respiratory hoods, which consist of a hood made of an insulating material and a transparent visor that defines a closed chamber that completely surrounds the user's head. These hoods usually have a hole at the back that is connected to a tube that leads to an external device (e.g., an oxygen tank) that generates an airflow within the hood.

[0010] One drawback of these respiratory hoods is that the tubing and external equipment can make it difficult for the user to move (e.g., if the tubing gets caught on furniture or the external equipment is an oxygen tank), making it difficult to perform tasks.

[0011] Another drawback of this type of hood is that the air outlet is usually a hole located at the front of the hood, in the area close to the user's mouth. Since the area of ​​said front is almost entirely taken up by the visor, there is not enough area to accommodate a filter with the necessary area to filter the air passing through said hole. Thus, these known hoods are not designed to prevent the user from infecting a patient. Summary of the Invention [Problem to be solved by the invention]

[0012] Therefore, there is a need for an air filtration device that facilitates freedom of movement for the user and isolates both the user and the patient from infectious materials. [Means for solving the problem]

[0013] In order to achieve this object and to solve the technical problems mentioned above, and also to provide further advantages which may be derived later, the present invention relates to a protective air filtration device, comprising: - a fastening structure configured to be fastened to a head of a user; - a visor associated with a fastening structure; a hood associated with the fastening structure and defining a closed chamber after fastening the fastening structure to the user's head; a rear air inlet provided with an inlet filter; - an air outlet; - a fan configured to generate an air flow from the air inlet through the upper air duct and through a front of the closed chamber to an air outlet; An air filtration device comprising:

[0014] The air outlet is disposed on at least one side and includes an outlet filter, a side frame, and a side cover. The side cover has at least one air passage opening and a curved surface that defines an air chamber between the outlet filter and the side cover. The side cover is configured to be secured to the side frame, and the outlet filter is secured between the side frame and the side cover.

[0015] Rear, top, side and front are understood as different positions of the device relative to the user's head when the device is in the use position. Thus, the combination of the visor and the hood defines a closed chamber around the user's head, isolating the user's head from infectious materials from outside and vice versa.

[0016] In addition, the airflow generated by the fan supplies the user with filtered air from the outside, protecting him from infectious agents that may be present in the air. The device is therefore independent of heavy objects that may limit the user's freedom of movement.

[0017] Furthermore, because the airflow is directed to the front of the closed chamber, the user continues to receive proper ventilation.

[0018] Because air flows through the front of the closed chamber, i.e., the portion where the visor is located, the likelihood of the visor fogging up due to condensation from the user's breath is reduced.

[0019] As shown, the air outlet is located on at least one side of the device in the position of use, preferably near at least one ear of the user. More preferably, air outlets are provided on both sides. In this way, the area available for the air filter is doubled and better distribution of airflow around the user's face is obtained.

[0020] Thus, since the sides of the device have a large area not taken up by the visor, it is possible to place an outlet filter at the air outlet with the necessary area for the air filtration device to function properly. Furthermore, when the outlet filter is placed at the side, its location and large area reduces the amount of moisture that accumulates from the breath exhaled by the user, thus increasing the lifespan of the outlet filter as it can be used for a longer period of time before it becomes saturated.

[0021] Likewise, it is conceivable for the side frames to be fixed to the hood, but this does not exclude them being fixed to a fastening structure.

[0022] Furthermore, since the outlet filter is fixed between the side frame and the side cover, the outlet filter can be easily replaced.

[0023] Additionally, the air chamber between the outlet filter and the side cover allows most of the outlet filter area to be used for filtering air passing through the air outlet.

[0024] Preferably, the side frame has a ribbed outer surface on which the outlet filter is mounted, which leaves a space between the outlet filter and the outer surface of the side frame, so that most of the outlet filter is used to filter the air passing through the air outlet. The ribs on the side frame promote condensation of moisture in the air passing through the air outlet, which increases the life of the outlet filter.

[0025] Preferably, the side cover is provided with ribs on the curved surface on which the outlet filter is installed. The ribs can reduce the area of ​​the outlet filter that contacts the curved surface of the side cover. Thus, most of the outlet filter is used to filter the air passing through the air outlet. Similarly, these ribs on the side cover promote condensation of moisture in the air passing through the air outlet, and extend the life of the outlet filter.

[0026] Preferably, the upper air duct comprises multiple sub-ducts for distributing the airflow evenly along the visor to avoid discomfort to the user due to the airflow concentrating in a single area of ​​the user's face and to prevent fogging of the visor.

[0027] Preferably, the inlet filter has a larger filtering capacity than the outlet filter. In this way, the area of ​​the outlet filter required for the air filtration device to function properly is reduced. This is because the size of the outlet filter is related to the airflow rate passing through it, i.e. the higher the airflow rate, the larger the outlet filter area required, and the larger the outlet filter material, i.e. the filtering capacity of the outlet filter material, the larger the outlet filter area required. Similarly, the airflow rate is directly related to the area of ​​the inlet filter, i.e. the larger the inlet filter area, the higher the airflow rate, and is also related to the inlet filter material, i.e. the higher the filtering capacity of the inlet filter, the lower the airflow rate, and is also related to the power of the fan, i.e. the higher the fan power, the higher the airflow rate.

[0028] Preferably, the device is equipped with an external power supply unit that can be fastened to the user's waist, making the device more portable.

[0029] Preferably, the device comprises sound amplification means including at least a microphone, a headset and / or a loudspeaker to enable communication between the user and the outside, so that the user can clearly hear sounds from outside the closed chamber and / or vice versa. It is conceivable that the microphone and / or the loudspeaker are located outside the closed chamber and the headset and / or the microphone are located inside the closed chamber. Preferably, the sound amplification means is configured to cancel sounds emitted by the airflow and / or ambient sounds from the outside, for example by cancelling certain frequencies, thereby reducing discomfort and improving hearing for the user.

[0030] Preferably, the device comprises a control unit configured to adjust the speed of the fan, for example by means of an embedded algorithm, for turning on, off, power control and / or rotation of the fan motor, thereby allowing further control of the airflow in the closed chamber. For this purpose, it is conceivable that the control unit comprises at least one processor.

[0031] Preferably, the device comprises at least one airflow characteristic sensor within the closed chamber. The control unit is configured to receive information from the airflow characteristic sensor, and in particular to continuously monitor the information received from the airflow characteristic sensor and contribute to various functions of the control unit, such as adapting the fan speed.

[0032] Preferably, the airflow characteristic sensor is a flow sensor or flow meter that measures the flow rate at the airflow inlet to the closed chamber.

[0033] The use of a CO2 concentration sensor to prevent the control unit from exceeding a set value for the CO2 concentration is not excluded.

[0034] Likewise, it is not excluded that the air flow characteristics sensor is a pressure sensor, a temperature sensor, etc., or any combination thereof.

[0035] Preferably, the control unit is configured to maintain a maximum pressure difference between the outside atmospheric pressure and the inside of the closed chamber of up to 0.5 mBar. In this way, the control unit can provide an air inlet flow rate into the closed chamber suitable to provide the user with enough breathing air to perform difficult tasks, while at the same time ensuring that the pressure difference between the inside of the closed chamber and the outside atmospheric pressure does not exceed 0.5 mBar. This feature avoids discomfort for the user.

[0036] Preferably, the device comprises identification means for unambiguously identifying the device by means of a unique digital tag processed by the control unit. This tag contains a set of relevant information called attributes. These attributes can only be changed if a set of conditions are fulfilled. The identity of the device is thus defined by this unique tag, which has attributes such as the coded name of the user to whom the device is assigned, the number of times the assigned person has worn the device, the number of hours between the time the assigned person wears the device and the time it is removed, when the CO2 level or air flow exceeds programmed limits, etc.

[0037] Preferably, the device comprises data encryption means for the data processed by the control unit, in particular by means of an encryption algorithm. The encryption can be performed using "blockchain" and / or "tokenization" technologies. The information providing the device with a digital identity allows, by means of an encryption algorithm, to securely register information related to the device in the blockchain network, facilitating the maintenance, cleaning and reassignment of the device to another user. Similarly, the related information may be the identity and some attributes (e.g. username, battery state, time of use, last use, last disinfection, etc.) and can be updated as the life of the device elapses. In this way, the information is transformed into a non-fungible token ("NFT"), which is created in the "blockchain" and managed through a "smart contract". The programming of the "smart contract" also makes it possible to assign the device to a specific user, so that only this user can activate it. This concept corresponds to that of a unique programmable electronic key that is personalized over a period of time, increasing the user's attention to the maintenance and security of the device.

[0038] By identifying several air filtration devices within the “blockchain” network, the “smart contract” programming will be able to collect user information and compare the usage of the device according to the user profile, its location, the need to update the material or electronic device when new functions and maintenance improvement processes are created.

[0039] Preferably, the control unit comprises wireless Internet connection means, in particular via WI-FI, Bluetooth technology, Zigbee technology, Near Field Communication (NFC) technology, GSM, as well as transmitting and receiving point-to-point information such as "LoRa" and / or technologies related to the Internet of Things (IoT) such as Sigfox, more particularly using frequencies in the ISM (Industrial, Scientific and Medical) radio band and proprietary protocols, to connect directly to a server or to intermediate nodes.

[0040] Extracting data over the life of the device allows statistical data to be extracted to improve the device in the future and add more features, so that another attribute of the device could be an updated version number of the algorithm with new features.

[0041] Likewise, an object of the invention is a cleaning system for an air filtration device, including sterilization means for sterilizing the device by means of UV-C radiation, thereby ensuring that the air filtration device is properly disinfected between uses and that the UV-C light is irradiated in a safe manner that is not harmful to humans.

[0042] In addition, this cleaning can be combined with charging of the external power unit. It is envisaged that the sterilisation means may be in the form of a sleeve into which the device is inserted.

[0043] By capturing initial data on the deployment of air filtration devices in a secure and anonymous manner, potential faults can be accurately predicted and addressed, minimizing maintenance time.

[0044] Data transmitted securely on the “blockchain” can be collected over several time periods to visually represent adoption and usage data, allowing for a clear visual display of adoption and encouraging use in specific locations.

[0045] Defining the air filtration device as an "NFT" will make it possible to collect feedback from each user in the future to improve each user's specific device, and also allow different experts to share suggestions on the use of new functions, facilitating their acquisition and minimizing negative impacts on sustainability.

[0046] Non-limiting examples of the present invention will now be described with reference to the accompanying drawings. [Brief description of the drawings]

[0047] [Figure 1] 1 is a perspective view of a preferred exemplary embodiment of an air filtration device according to the present invention; [Diagram 2] FIG. 2 is an elevational view of the apparatus of FIG. 1 with a portion of the interior visible. [Diagram 3] FIG. 2 is an exploded perspective view of the air filtering device. [Figure 4] FIG. 1 is a perspective view showing the steps to be followed to properly position an air filtration device. [Diagram 5] FIG. [Figure 6A-6F] FIG. 13 is a perspective view showing the steps to be followed to remove the inlet filter. [Figure 7] FIG. 2 is a top view of the upper air duct, showing diagrammatically the air distribution subducts at the outlet of the air duct; [Figure 8] FIG. [Figure 9] FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0048] The non-limiting example shown in Figures 1 to 9 corresponds to an air filtering device 1. The air filtering device 1 is provided with a transparent visor 2 to allow a user's field of vision to be visible when the air filtering device 1 is worn on the user's head.

[0049] As shown in Figures 1 and 2, the visor 2 is attached to a fastening structure 3. The fastening structure 3 is configured to be fastened to a user's head.

[0050] The visor 2 is positioned such that when the fastening structure 3 is fastened to the user's head, the visor 2 is in front of the user's face, as shown in Figures 4c and 4d, at a distance such that a suitable gap remains between the face and the visor 2. Thus, the possibility of the visor 2 fogging up is limited and discomfort caused when the visor 2 is too close to the face is reduced.

[0051] The fastening structure 3 comprises projections 3.1 for support on the user's head, as shown in figure 2. These projections 3.1 may conceivably be cushioned to improve the comfort of the user.

[0052] Similarly, the fastening structure 3 comprises fastening means 3.2. In the illustrated example, the fastening means 3.2 comprises a strap 3.2.1 and a fastener 3.2.2. The fastener 3.2.2 comprises a means for adjusting the fastening force so that the user can properly wear the air filtering device 1 on his / her head.

[0053] The air filtering device 1 further comprises a hood 4 which is secured to both the visor 2 and the fastening structure 3. When the fastening structure 3 is fastened to the user's head, the hood 4 encircles the user's head and neck. When the air filtering device 1 is worn on the user's head, the hood 4 and the visor 2 define a closed chamber 7 around the user's head, as shown in FIG.

[0054] Preferably, the hood 4 is made of a material that prevents the passage of air, such as a material complying with the UNE EN13795 standard, and prevents the passage of infectious substances from the outside to the inside of the closed chamber 7 and vice versa.

[0055] To ensure airtightness of the closed chamber 7, the hood 4 is provided with airtight closure means 4.1 (eg cord, tie, etc.) at the bottom of the hood 4.

[0056] The lower part of the hood 4 is understood as the area of ​​the hood 4 that is at its lower end when the air filtering device 1 is worn on the user's head.

[0057] 2, the air filtering device 1 includes a control unit 10. In the illustrated example, the control unit 10 is fixed to a fastening structure 3.

[0058] In this example, an external unit 11 is also provided for supplying power to the control unit 10. The external unit 11 comprises electrical connection means 11.1 for electrically connecting the external unit 11 to the control unit 10.

[0059] It should be noted that although in this preferred exemplary embodiment the use of an external unit 11 for supplying power is mentioned, it is not excluded that the air filtering device 1 is provided with a battery inside the closed chamber 7 for supplying power to the control unit 10.

[0060] 4 shows the steps to be followed to mount the air filtering device 1 on the user's head. These steps are as follows: a) holding the air filtering device 1 so that the fastening structure 3 is not covered by the hood 4; b) placing the fastening structure 3 on the user's head so that the visor 2 is in front of the user's face and fastening the straps 3.2.1 behind the head with the fasteners 3.2.2; c) the closure means 4.1 of the hood 4, in this case a cord, ensuring the airtightness of the closed chamber 7; and d) The external unit 11 is fastened to the waist and connected to the air filtering device 1 by means of electrical connection means 11.1.

[0061] The air filtering device 1 comprises an air inlet 5 for passing breathable air into a closed chamber 7. Said air inlet 7 comprises an inlet filter 5.1 for filtering the air passing through said air inlet 5 to ensure that the air entering the closed chamber 5 is free of infectious substances.

[0062] In order to generate an air flow 12 from the outside of the air inlet 5 to the inside of the closed chamber 7, the air inlet 5 has one side leading to the outside of the closed chamber 7 and the other side connected to a fan 8, more specifically a centrifugal fan 8.

[0063] The fan 8 is configured to draw air from outside the closed chamber 7 through the inlet filter 5.1. Similarly, the fan 8 is configured to introduce a flow rate, for example of more than 120 l / min, into the air duct 9. The air duct 9 is configured to distribute the flow rate of the air flow 12 to the front of the closed chamber 7.

[0064] As shown in Figure 5, the air inlet 5 comprises a cover 5.2 which protects the inlet filter 5.1 from splashes or impacts which may affect the filtering capacity of the inlet filter 5.1. Furthermore, the cover 5.2 comprises an inlet hole 5.2.1 through which air flows in from the outside.

[0065] The inlet filter 5.1 is mounted in an inlet frame 5.1.1 which can be fixed by means of a bayonet fitting to a cavity 8.1 of the fastening structure 3 in which the fan 8 is located.

[0066] As shown in FIG. 5, the hood 4 remains fixed to the air inlet 5 by being sandwiched between the inlet frame 5.1.1 and the cavity 8.1.

[0067] As shown in Figures 6A-6F, the air inlet 5 is configured so that the inlet filter 5.1 can be removed. To do this, first the cover 5.2 is removed to expose the inlet frame 5.1.1, as shown in Figures 6A-6C. Then, the inlet frame 5.1.1 is rotated, disengaged from the fan 8 and separated from the air outlet 6, as shown in Figures 6D-6F. Finally, these steps are repeated in reverse order to place a new inlet filter 5.1 with its corresponding inlet frame 5.1.1.

[0068] As shown in FIG. 2, an air duct 9 is disposed on the upper portion of the air filtering device 1 .

[0069] As previously mentioned, rear, top, side and front are understood to be different positions of the air filtering device 1 relative to the user's head when the device is in the use position.

[0070] As shown in figure 7, the air duct 9 comprises several sub-ducts 9.1, shown diagrammatically, whose position and extent may vary according to design and need. The sub-ducts 9.1 allow for a uniform distribution of the air flow 12 at the outlet of the air duct 9, in the area opposite the fan 8. The outlet of the air duct 9 is located in front of the closed chamber 7, more specifically at the top of the visor 2.

[0071] The upper part of the visor 2 is understood as the area of ​​the visor 2 which is at its upper end when the air filtering device 1 is in the use position.

[0072] It is also envisaged that the air duct 9 is equipped with LED lighting means 9.3 in communication with the control unit 10. This LED lighting means 9.3 is positioned so as to be within the user's field of view when the air filtering device 1 is in the use position.

[0073] In this way, the control unit 10 can inform the user of the various states of the air filtering device 1 by a series of colors (e.g., green when conditions are optimal, orange when the battery level of the external unit 11 is low, etc.).

[0074] Similarly, the air duct 9 is provided with a housing 9.2 for housing an air flow characteristic sensor for the air flow entering the air duct 9.

[0075] Preferably, the air flow characteristic sensor is a flow meter and is in communication with the control unit 10 , which receives information regarding the inlet flow rate of the air flow 12 .

[0076] It is not excluded that the airflow characteristic sensor is a CO2 concentration sensor, a pressure sensor, a temperature sensor, etc., nor is it excluded that the device comprises several airflow characteristic sensors.

[0077] Using the information obtained from the airflow characteristic sensor, the control unit 10 can control the fan 8 (turn the fan on, off, vary the motor power and / or rotation speed, etc.) to maintain a maximum pressure difference between the atmospheric pressure outside the closed chamber 7 and the inside of the closed chamber 7 of up to 0.5 mBar.

[0078] The pressure difference between the pressure outside this closed chamber 7 (eg 1 atmosphere, ie 1013.25 mBar) and the pressure inside (in this example between 1013.25 mBar and 1013.75 mBar) ensures that the user is properly ventilated.

[0079] As shown in Figure 8, the air outlet 6 is located on at least one side of the air filtering device 1 and is equipped with an outlet filter 6.1, so that the user's infectious material is effectively filtered by the outlet filter 6.1 as it leaves the closed chamber 7.

[0080] The dimensions of the inlet filter 5.1 and the outlet filter 6.1 are determined depending on the inlet flow rate of the air flow 12 so that the pressure difference in the closed chamber 7 is less than 0.5 mBar. In other words, the higher the flow rate, the larger the required area of ​​the inlet filter 5.1 and the outlet filter 6.1.

[0081] In the non-limiting example shown in the drawings, the air filtering device 1 comprises two air outlets 6. The air outlets 6 may be identical or have different characteristics. Each air outlet 6 comprises an outlet filter 6.1, which are arranged on either side of the device 1. In this way, the effective area of ​​the outlet filters 6.1 is doubled, resulting in a better distribution of the air flow 12 through the visor 2 and around the user's face.

[0082] 8, each air outlet 6 comprises a side frame 6.2 fixed to the hood 4. Said side frame 6.2 comprises an outlet hole 6.2.1 for air to exit from the interior of the closed chamber 7.

[0083] Similarly, the side frame 6.2 is provided with ribs 6.2.2 on the outer surface of the side frame 6.2, which make it possible to absorb condensation of moisture in the air passing through the air outlet 6. Furthermore, the ribs 6.2.2 leave a space between the outlet filter 6.1 and the outer surface of the side frame 6.2, thus making most of the area of ​​the outlet filter 6.1 available for filtering the air passing through the air outlet 6.

[0084] In the non-limiting example shown in the drawings, the side cover 6.3 is configured to be attached to the side frame 6.2 by snapping or clipping. The side cover 6.3 can protect the outlet filter 6.1 from splashes or impacts that may affect the filtering capacity of the outlet filter 6.1. The side cover 6.3 comprises an opening 6.3.1 for the air flow 12 to pass through the air outlet 6. In order to make it easy to remove the side cover 6.3 when the outlet filter 6.1 needs to be replaced, a flange 6.4 is provided on both the side frame 6.2 and the side cover 6.3.

[0085] Similarly, the side cover 6.3 has a curved surface which defines an air chamber between the surface of the outlet filter 6.1 and the side cover 6.3. In this way, it is ensured that the entire surface of the outlet filter 6.1 can be used to filter the air passing through the air outlet 6.

[0086] The side frame 6.2 is provided with ribs 6.2.2 on the outer surface of the side frame 6.2, said ribs 6.2.2 making it possible to absorb condensation of moisture in the air passing through the air outlet 6.

[0087] Additionally, the side cover 6.3 includes ribs 6.3.2 on the curved surface, as shown in FIG.

[0088] In a preferred exemplary embodiment, first the outlet filter 6.1 is placed on the ribs 6.3.2 of the side cover 6.3, and then the side cover 6.3 is fixed to the side frame 6.2 without touching the outlet filter 6.1.

[0089] In another preferred exemplary embodiment, the outlet filter 6.1 is first placed on the ribs 6.2.2 of the side frame 6.2, and then the side cover 6.3 is fixed to the side frame 6.2 without touching the outlet filter 6.1.

[0090] The material of the inlet filter 5.1 is assumed to have a filtering capacity according to category P3 according to the UNE EN 143:2021 standard, which specifies the performance requirements and test methods for filters designed to filter particles (i.e. capable of filtering viruses, among other things). The air introduced inside the closed chamber 7 is highly filtered, which is very important when the user comes into contact with patients with highly contagious contagious diseases.

[0091] Similarly, the material of the outlet filter 6.1 is assumed to have a filtering capacity in accordance with the Type II category of the UNE EN 14683:2019 standard, which specifies the performance requirements and test methods for filters designed to filter bacteria.

[0092] In this way, the inlet filter 5.1 filters all air entering the closed chamber 7 to protect the user from external particles and viruses, and the exhaled air is filtered by the outlet filter 6.1, filtering out bacteria, i.e. any influence the user may have on the air filtered at the air inlet 5.

[0093] The air exhausted through the air outlet 6 is pre-filtered by the inlet filter 5.1. As this air only contains the user's infectious substances, there is no need to use an outlet filter 6.1 with a filtering capacity according to the UNE EN 143:2021 standard.

[0094] The material of the inlet filter 5.1 has a greater filtering capacity than the outlet filter 6.1. In this way, the area of ​​the outlet filter 6.1 required for the air filtration device 1 to function properly is reduced.

[0095] For example, if the material of the outlet filter 6.1 complies with the UNE EN 143:2021 standard (category P3) and the area of ​​the outlet filter 6.1 is not changed, a pressure difference of more than 0.5 mBar between the outside and the inside of the closed chamber 7 would be required, which would cause discomfort to the user. This would require an increase in the area of ​​the outlet filter 6.1 and thus the air outlet 6 and the air filtering device 1, resulting in discomfort to the user (e.g. due to increased weight, volume, etc.).

[0096] It is also conceivable that the external unit 11 comprises a loudspeaker so that the user's voice can be clearly heard outside the closed chamber 7 .

[0097] Likewise, it is conceivable that the control unit 10 is located in an external unit 11 .

[0098] It is also envisaged that the control unit 10 may be configured to perform the following tasks: - Fan 8 noise cancelling, which improves the user's hearing; - Bluetooth® communication for telephone communication, use of a digital stethoscope, or communication with the user's headphones - Increase the volume of the loudspeaker on the external unit 11 for patients with hearing impairments - Analyze the frequency of use of the air filtration device 1 and the user's movements; - Verify the identity of the user, - The user is notified, usually by means of LED lighting means 9.3, when the inlet and / or outlet filters 6.1 need to be replaced.

Claims

1. A protective air filtration device (1), comprising: a fastening structure (3) configured to be fastened to a user's head; a visor (2) associated with said fastening structure (3); a hood (4) associated with said fastening structure (3) and defining a closed chamber (7) after said fastening structure (3) is fastened to a user's head; a rear air inlet (5) equipped with an inlet filter (5.1); An air outlet (6); a fan (8) configured to generate an air flow (12) from the air inlet (5) through an upper air duct (9) through the front of the closed chamber (7) to the air outlet (6); the air outlet (6) is arranged on at least one side, the air outlet (6) comprises an outlet filter (6.1), a side frame (6.2) and a side cover (6.3), the side cover (6.3) having at least one air passage opening (6.3.1) and a curved surface defining an air chamber between the outlet filter (6.1) and the side cover (6.3), the side cover (6.3) being configured to be fixed to the side frame (6.2), the outlet filter (6.1) being fixed between the side frame (6.2) and the side cover (6.3).

2. 2. Air filtering device (1) according to claim 1, characterized in that the side frame (6.2) has an outer surface provided with ribs (6.2.2) on which the outlet filter (6.1) is mounted.

3. 10. Air filtering device (1) according to any of the preceding claims, characterized in that the side cover (6.3) is provided with ribs (6.3.2) on the curved surface on which the outlet filter (6.1) is placed.

4. 10. Air filtering device (1) according to any of the preceding claims, characterized in that the upper air duct (9) comprises a number of sub-ducts (9.1) for uniformly distributing the air flow (12) along the visor (2).

5. 10. An air filtering device (1) according to any of the preceding claims, characterized in that the inlet filter (5.1) has a greater filtering capacity than the outlet filter (6.1).

6. An air filtering device (1) according to any of the preceding claims, characterized in that it comprises an external power supply unit (11) which can be fixed to the waist of the user.

7. An air filtering device (1) according to any of the previous claims, characterized in that it comprises sound amplification means, including at least a microphone, a headset and / or a loudspeaker, to enable communication between the user and the outside.

8. Air filtering device (1) according to claim 7, characterised in that the sound amplification means are arranged to cancel sounds emitted by the air flow (12) and / or ambient sounds from outside.

9. An air filtering device (1) according to any of the preceding claims, characterized in that it comprises a control unit (10) adapted to regulate the speed of the fan (8).

10. 10. The air filtering device (1) according to claim 9, characterized in that it comprises at least one air flow (12) characteristic sensor in the closed chamber (7), and the control unit (10) is configured to receive information from the air flow (12) characteristic sensor, in particular to continuously monitor the information received from the air flow (12) characteristic sensor.

11. The air filtration device (1) according to any one of claims 9 to 10, characterized in that the control unit (10) is configured to maintain a maximum pressure difference between the atmospheric pressure outside and the interior of the closed chamber (7) of up to 0.5 mBar.

12. Air filtration device (1) according to any of claims 9 to 11, characterized in that it comprises identification means for unambiguously identifying the device (1) by means of a unique digital tag processed by the control unit (10).

13. An air filtration device (1) according to any of claims 9 to 12, characterized in that it comprises data encryption means for the data processed by the control unit (10), in particular by means of an encryption algorithm, more particularly the encryption being performed using "blockchain" and / or "tokenization" technologies.

14. Air filtering device (1) according to any of claims 9 to 13, characterized in that the control unit (10) comprises wireless Internet connection means, in particular via WI-FI, Bluetooth, Zigbee, NFC, GSM, LoRa and / or Sigfox, more particularly using frequencies in the ISM band and proprietary protocols, to connect directly to a server or to an intermediate node.

15. A cleaning system for an air filtration device (1) according to any of the previous claims, characterized in that it comprises sterilization means for sterilizing said device (1) by means of UV-C radiation.

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