VENTILATION DEVICE FOR A FILTERING MASK

A ventilation device is disclosed for a filter mask engageable with the outer face of the cup of the filter mask. The device comprises: an inlet port which removably engages an opening of the cup of the mask; an outlet port in fluid communication with the inlet port; an exhalation valve arranged between the inlet port and the outlet port; an extraction fan arranged between the inlet port and the exhalation valve; a sensor arranged at the inlet port to detect the value of a physical quantity; a command and control unit in signal communication with the sensor and with the extraction fan. The command and control unit activates the extraction fan when the value of the physical quantity detected by the sensor exceeds a predefined threshold value.

TECHNICAL FIELD

The present invention relates to a ventilation device for a sealed filtering mask, such as for example an individual protection device for urban, medical and industrial use. The present invention also relates to a method for controlling the ventilation device. Furthermore, the present invention relates to a ventilation system comprising such a ventilation device.

BACKGROUND ART

It is known in the art to provide a sealed filtering mask comprising a filter cup which allows particles to be filtered, such as pollutants and microorganisms, thereby ensuring the inhalation of air with a better quality.

It is also known to provide filtering masks provided with an exhalation valve engaged with an opening of the filtering cup. The exhalation valve is configured to allow air to escape from the filter cup of the mask during exhalation, when a predefined pressure value is exceeded. This facilitates a better air exchange in the inner volume defined by the cup.

It is also known to provide a ventilation system, which is also engaged with the opening of the mask's cup. The ventilation system may be switched on by the user to extract air continuously from the cup of the mask, so as to guarantee an exchange of air by the expulsion of exhausted air from the inner volume defined by the cup of the mask.

SUMMARY OF THE INVENTION

In the prior art, the exhalation valve does not guarantee a correct exchange of air inside the mask, because the operation of the valve does not always coordinate with the respiratory rhythm of the person wearing the mask. This results in pressure imbalance within the filter cup, which hinders proper breathing of the person. Moreover, humidity and temperature conditions may be created inside the mask, which might hinder breathing. However, the pressure could still remain below the threshold value needed for the opening of the exhalation valve. This condition leads to an insufficient exchange of air inside the filter cup.

Moreover, the known masks with extraction fan, operating continuously, could cause a vacuum condition within the filter cup. This could hinder the normal breathing of the person wearing the mask. Moreover, the fan is not capable of avoiding possible opposite airflows from the outside toward the inside of the filter cup. Such airflows, although minimal, pass through the fan avoiding the filtering guaranteed by the cup, thus contaminating the air inhaled by the person. Moreover, in the prior art the extraction fan is positioned inside the filtering cup, in an attempt to limit the phenomenon of contamination due to the inlet of unfiltered air from the outside. This results in a larger footprint and a smaller volume useful for breathing inside the filter cup. Therefore, the same cup of the mask shall have a larger volume in order to accommodate the fan and at the same time ensure the circulation of air inside the mask in use. In this regard, it should be noted that the inner volume of the filter cup is reduced by at least 15-45% when worn by a person. For this reason, it is essential to maintain a useful volume for respiration as large as possible, while maintaining a standard of comfort and encumbrance of the mask for the wearer.

It is an object of the present invention to provide a ventilation device, a method for controlling the ventilation device and a ventilation system incorporating such a device, capable of overcoming at least in part the drawbacks of the prior art.

According to a first aspect of the present invention, a ventilation device is provided for a filtering mask which is removably attachable to the outer face of the filter cup of the filtering mask, comprising:an inlet port configured to detachably and fluid-tightly engage with an opening of the filter cup of the mask, and an outlet port in fluid communication with the inlet port;an exhalation valve arranged between the inlet port and the outlet port to allow an airflow from the inlet port to the outlet port when a pressure difference across the exhalation valve exceeds a predefined threshold value;an extraction fan arranged between the inlet port and the exhalation valve and configured to generate an airflow from the inlet port to the outlet port;at least one sensor arranged at the inlet port to locally detect the value of a physical quantity; anda command and control unit in signal communication with the at least one sensor and with the extraction fan and configured to activate the extraction fan when the value of the physical quantity detected by the sensor exceeds a predefined threshold value and to deactivate the extraction fan when the value of the physical quantity detected by the sensor falls below the predefined threshold value.

Preferably, the at least one sensor comprises at least one pressure sensor arranged at the inlet port to detect a local pressure value and the command and control unit is configured to activate the extraction fan when the local pressure value detected by the pressure sensor exceeds a predefined threshold value, and to deactivate the extraction fan when the local pressure value detected by the pressure sensor falls below the predefined threshold value.

Alternatively or in addition, the at least one sensor comprises at least one temperature sensor arranged at the inlet port to detect a local temperature value, and the command and control unit is configured to activate the extraction fan when the local temperature value detected by the temperature sensor exceeds a predefined threshold value and to deactivate the extraction fan when the local temperature value detected by the temperature sensor falls below the predefined threshold value.

Alternatively or in addition, the at least one sensor comprises at least one humidity sensor arranged at the inlet port to detect a local humidity value, and the command and control unit is configured to activate the extraction fan when the local humidity value detected by the humidity sensor exceeds a predefined threshold value and to deactivate the extraction fan when the local humidity value detected by the humidity sensor falls below the predefined threshold value.

Preferably, the ventilation device comprises a radio frequency communication module in signal communication with the command and control unit and configured to communicate with an external device.

Preferably, the ventilation device comprises a button which is manually operable by a user to activate and deactivate the extraction fan.

Preferably, the ventilation device also comprises:a battery for supplying at least the command and control unit, the extraction fan, the at least one sensor and the radio frequency communication module, if present;a memory unit in signal communication with the command and control unit;a casing suitable for containing at least the exhalation valve, the extraction fan, the at least one sensor, the command and control unit, the battery, the memory unit and the radiofrequency communication module, if present.

According to a preferred embodiment, the at least one sensor is positioned substantially at the center of the inlet port.

According to a preferred embodiment, the extraction fan is a centrifugal fan and the exhalation valve comprises a membrane arranged in a curved manner, with the concavity facing the outlet port.

According to a second aspect of the present invention, a ventilation system is provided comprising:a filtering mask comprising a filter cup provided with an inner face defining an inner volume and intended to be turned towards the face of a person when in use, the filter cup being provided with an outer face opposite to the inner face and intended to be turned outwards when in use; the filter cup being provided with an opening for placing the inner volume in fluid communication with the outside;a ventilation device as described above, attached removably on the outer face of the filter cup;an internal fastening element engaged in the opening in correspondence with the inner face of the filter cup and removably attached with the inlet port through the opening to keep the ventilation device detachably fixed on the outer face of the filter cup;

wherein the at least one sensor is configured to detect a value of the physical quantity at the inlet port, which is indicative of the value of the same physical quantity in the inner volume.

Preferably, the inner volume has a maximum value between 100 cm3and 200 cm3when the mask is kid-sized, or a maximum value between 200 cm3and 300 cm3when the mask is small adult-sized, or a maximum value between 300 cm3and 450 cm3when the mask is large adult-sized, or a maximum value between 450 cm3and 700 cm3when the mask is of the half-face type, or a maximum value between 700 cm3and 1000 cm3when the mask is of the full-face type.

According to a preferred embodiment, the ventilation system also comprises an application suitable for being run by an external device in communication with the ventilation device, the application being configured to receive data from the command and control unit and to display said data on a graphic interface of the external device, the data comprising at least one of: respiratory rate calculated by the command and control unit, speed of the extraction fan, usage time of the ventilation device and operating time of the extraction fan.

Preferably, the application is also configured to send instructions to the command and control unit to remotely control the operation of the extraction fan.

According to a third aspect of the present invention, a method of controlling a ventilation device as described above is provided, comprising the steps of:detecting local pressure values at predetermined time intervals using at least one pressure sensor;calculating a respiratory frequency value by processing the pressure values detected at predefined time intervals by the at least one pressure sensor, by using a predefined algorithm residing in the command and control unit;by the command and control unit, controlling the dynamic operation of the extraction fan as a function of the respiratory frequency value calculated at the previous step.

According to a further aspect, a ventilation device is provided for a filtering mask which can be attached onto the outer face of the filter cup of the filtering mask, comprising:an inlet port configured to engage removably and fluid-tightly with an opening of the filter cup of the mask, and an outlet port in fluid communication with the inlet port;an exhalation valve arranged between the inlet port and the outlet port to allow an airflow from the inlet port to the outlet port when a pressure difference across the exhalation valve exceeds a predefined threshold value;an extraction fan arranged between the inlet port and the exhalation valve and configured to generate an airflow from the inlet port to the outlet port;at least one pressure sensor arranged at the inlet port to detect local pressure values;a command and control unit in signal communication with the sensor and with the extraction fan and configured to calculate a respiratory frequency value by processing the pressure values detected by the at least one pressure sensor, and to control dynamically the operation of the extraction fan as a function of the calculated respiratory frequency value.

Advantageously, the ventilation device can also be applied to the filtering masks available on the market, in order to optimize their operation.

Advantageously, the ventilation device according to embodiments of the present invention is capable of ensuring a better exchange of air during use.

Advantageously, the ventilation device according to embodiments of the present invention is capable of ensuring a better quality of the air inhaled by the person wearing the filtering mask on which it is applied.

Advantageously, the ventilation device according to embodiments of the present invention is capable of regulating the extraction of air as a function of the respiratory rhythm and the environmental conditions inside the filter cup of the mask.

Advantageously, the method according to embodiments of the present invention allows to control the operation of the device dynamically, in order to guarantee an optimal air exchange during the use of the mask.

Advantageously, the ventilation system according to embodiments of the present invention is capable of ensuring optimum breathing condition even during sports activities, without renouncing a correct filtering of the inspired air.

The device and the ventilation system illustrated in the accompanying figures are to be understood as being schematically represented, not necessarily on scale and not necessarily with the represented proportions between the various constituent elements.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

The present invention relates to a ventilation device D for a filtering mask, illustrated in the accompanying drawings. The ventilation device D may be applied to a filtering mask1, such as a commercially available mask, of the type for industrial, urban, sports, medical and military use. Examples of known masks are of the type with filter cups, folding cups, half masks, full face masks etc. A mask1of known type is provided with a filter cup C having an outer face and an opposite inner face I. The inner face I is intended to face, during use, the face of the user wearing the mask1. The outer face E is instead intended to face outwardly when the mask1is in use. The mask1comprises an opening O formed in the filter cup C, which during use places in fluid communication the inner volume V defined by the inner face I of the filter cup C with the outer environment. Moreover, the mask1may typically comprise ties, elastic straps or other means which allow to stably and comfortably fix the mask1to the face of the wearer.

Within the scope of the present invention, for the sake of brevity, reference is made to the inner volume V as the volume defined by the inner face I of the filter cup C. The inner volume V may be calculated by CAD from 3D models representative of the shape of the filter cup C of the mask1. However, it should be noted that this volume is calculated, for uniformity of evaluation, by considering the filter cup C in its shape before use by a user. As noted above, indeed the inner volume V is reduced from 15% to 45% during use, i.e. when the mask1is worn by a user (FIGS.2and2a). This is due to the fact that the inner volume V, in use, is defined between the inner face I of the filter cup C and the face of the user closing the aperture of the filter cup C. Moreover, the mask itself could undergo deformations to fit the profile of the face. Therefore, for the sake of simplicity of illustration, the inner volume V is calculated taking into account the volume defined by the inner face I of the filter cup C alone, considering the presence of an ideal and uniform part to close the opening of the filter cup C.

The ventilation device D is configured to be engaged, preferably removably, on the outer face E of the filter cup C of a filtering mask1. The ventilation device D comprises an inlet port IN configured to removably and fluid-tightly engage the opening O of the filter cup C of the mask1.

The ventilation device D also comprises an outlet port OUT in fluid communication with the inlet port IN. According to the embodiment shown in the drawings, the outlie port OUT is facing downwards. This way, advantageously, the exhaled air is exhausted downwards, thereby preventing e.g. the fogging of glasses or visor which the user might wear.

The ventilation device D comprises an exhalation valve7arranged between the inlet port IN and the outlet port OUT, to allow the airflow from the inlet port IN to the outlet port OUT when the pressure difference across the exhalation valve7exceeds a predefined threshold value. The exhalation valve7may comprise a membrane valve. The membrane valve may be made of a silicone material.

According to an advantageous embodiment, as shown e.g. inFIGS.7aand7b, the body of the valve7defines a curved housing where the membrane is arranged. The membrane arranged in the housing is also curved, with its concavity facing the outlet port OUT.

The ventilation device D further comprises an extraction fan3arranged between the inlet port IN and the exhalation valve7. The extraction fan3is configured to generate an airflow from the inlet port IN toward the outlet port OUT. Preferably, the extraction fan3comprises a centrifugal fan. The inventors have realized that using a centrifugal fan is advantageous over other types of fan (e.g. axial fans), because the centrifugal fan preserves its efficiency even in the presence of high pressure variations which typically occur within the ventilation device D during the breathing cycle of the user. The inventors have estimated that using a centrifugal fan in combination with the exhalation valve7with curved membrane as described above allows reaching a particularly high extraction efficiency.

In addition, the ventilation device D comprises at least one sensor4arranged at the inlet port IN, to locally detect the value of a physical quantity. In other words, the sensor4detects a physical quantity, such as pressure, temperature or humidity, and generates a signal as a function of the detected value. It should be noted that the positioning of the at least one sensor4at the inlet port IN allows to detect a value of a physical quantity which corresponds substantially to the value of the same physical quantity in the inner volume V, when the device is in use and therefore applied to a mask1worn by a user. Preferably, the sensor4is arranged at the inlet port IN to further improve its capability of detecting the physical quantity of interest indicative of the value of this quantity in the inner volume V of the mask1. More preferably, the sensor4is supported substantially at the center of the inlet port IN. For example, the sensor4may be arranged at the center of a ring mounted on the inlet port IN of the device D, as shown inFIG.5. In particular the sensor4may be mounted on a central part of the ring which is joined to the edge of the ring by means of rays.

The ventilation device D preferably comprises also a command and control unit5in signal communication with the at least one sensor4and with the extraction fan3(see block diagram inFIG.8). Preferably, the command and control unit5comprises a printed board circuit (PCB).

The command and control unit5is configured to receive the signals generated by each sensor4and process them to quantify the value of the physical quantity detected. As will be described in greater detail hereinafter, the command and control unit5is also configured to activate and/or deactivate the extraction fan3on the basis of the value of the physical quantity detected. In particular, the command and control unit5is preferably configured to activate the extraction fan3when the value of the physical quantity detected by the sensor4exceeds a predefined threshold value, and is also configured to deactivate the extraction fan3when the value of the physical quantity detected by the sensor4falls below the predefined value.

According to a preferred embodiment of the invention, the at least one sensor4comprises at least one pressure sensor arranged at the inlet port IN to detect a local pressure value. Preferably, the pressure sensor is a piezoelectric sensor.

According to this embodiment, the command and control unit5is configured to activate and/or deactivate the extraction fan3on the basis of the local pressure value detected. In particular, according to this embodiment, the command and control unit5is configured to activate the extraction fan3when the local pressure value detected by the pressure sensor exceeds a predefined threshold value, and to deactivate the extraction fan3when the local pressure value detected by the pressure sensor falls below the predefined threshold value. Advantageously, the extraction fan3is then activated automatically upon detection of a local pressure greater than the predetermined threshold value when the mask1is worn, using the measured data of the pressure sensor.

According to an embodiment of the invention, the command and control unit5is configured to calculate a respiratory frequency value of the user wearing the mask1as a function of the signals received from the pressure sensor, and to activate/deactivate the extraction fan3according to the value of the respiratory frequency detected. Advantageously, in this way the extraction fan3is automatically activated upon the detection of a respiratory frequency when the mask1is worn, using the measured data of the pressure sensor.

Independently of whether the extraction fan3is automatically operated upon detection of a local pressure greater than the threshold value or of a respiratory frequency, in any case, according to an embodiment, the command and control unit5is configured to automatically adjust the rotation speed of the extraction fan3when the fan3is activated, by reducing or increasing the airflow that is extracted, as the user's breathing frequency varies. As the respiratory frequency increases, the extraction speed of the extraction fan3increases and, vice versa, as the respiratory frequency decreases, the extraction speed of the fan decreases.

According to a further preferred embodiment of the invention, the at least one sensor4comprises at least one temperature sensor arranged at the inlet port IN to detect a local temperature value. The command and control unit5is configured to activate and/or deactivate the extraction fan3based on the detected temperature value. In particular, the command and control unit5is configured to activate the extraction fan3when the local temperature value detected by the temperature sensor exceeds a predefined threshold value, and to deactivate the extraction fan3when the local temperature value detected by the temperature sensor falls below the predefined threshold value.

According to a preferred embodiment, the at least one sensor4comprises at least one humidity sensor arranged in proximity to the inlet port IN to detect a local humidity value. The command and control unit5is configured to activate and/or deactivate the extraction fan3based on the detected humidity value. In particular, the control unit5is configured to activate the extraction fan3when the local humidity value detected by the humidity sensor exceeds a predefined threshold value, and to deactivate the extraction fan3when the local humidity value detected by the humidity sensor falls below the predefined threshold value.

It should be pointed out that the preferred embodiments described above in connection with pressure, temperature and humidity sensors may be alternative or combined. Preferably, the various types of sensors4are provided within a single module. In the case of a combination of two or more types of sensors amongst pressure, temperature and humidity, the command and control unit5processes, according to a predefined algorithm, the signals obtained by the different sensors4and therefore the overcoming of the respective preset threshold values. For example, the extraction fan3may be activated when one of the physical quantities measured exceeds the respective predetermined threshold value. Alternatively, the command and control unit5may process according to the predefined algorithm the signal received by the various sensors4to generate a reference parameter which also takes into account certain operating conditions; the result of the processing is the parameter to which the threshold for activating the extraction fan3is applied. For example, in order to refine the reading of the respiratory frequency, eliminating and filtering out any vibrations in the person's breath given by the speech or by the current effort, the predefined algorithm constantly assigns and updates weights that give value to the data acquired by the pressure sensor4, generating a new value which depends on the respiration rate; on this value the threshold is applied which determines the actuation of the extraction fan3. Optionally, the algorithm resident in the command and control unit5also takes into account the specific combination of the different physical quantities detected to activate and deactivate the extraction fan3.

In accordance with a preferred embodiment of the invention, the ventilation device D comprises a radiofrequency communication module9, such as a Bluetooth communication module, in signal communication with the command and control unit5and configured to communicate with an external device10, such as a smartphone, a smartwatch, a tablet or a PC (see block diagram inFIG.8).

Preferably, the command and control unit5is configured to communicate with the external device10via the radiofrequency communication module9. The external device10executes a suitable predefined application11, which is configured to receive and process the data collected by the command and control unit5. Preferably, the predefined application11may also be used to send instructions to the command and control unit5to remotely control operation of the extraction fan3.

According to an embodiment, the ventilation device D comprises a push-button manually operable by a user to activate and deactivate the extraction fan3.

Preferably, the ventilation device D comprises one or more LEDs, optionally colored, configured to emit light signals indicative of the operating state of the ventilation device D.

According to an embodiment of the invention, the ventilation device D comprises a battery6for supplying at least the command and control unit5, the extraction fan3, the at least one sensor4and the radiofrequency communication module9, if present. It should be pointed out that the battery6is configured to supply any other component of the ventilation device D that may be present. The battery may be rechargeable.

According to embodiments of the invention, the ventilation device D also comprises a memory unit (see block diagram ofFIG.8), placed in signal communication with the command and control unit5to store the data collected by the sensors4and data relating to the operation of the extraction fan3.

According to an embodiment of the present invention, the ventilation device D comprises a casing2adapted to contain therein at least the exhalation valve7, the extraction fan3, the at least one sensor4, the command and control unit5, the battery6, the memory unit, the radiofrequency communication module9if present, and any other possible components of the ventilation device D.

The casing2preferably has a substantially “L” shape, comprising a section2awhich in use extends upwards and a section2bwhich in use extends backwards (i.e. towards the face of the user wearing the mask1). The two sections2aand2bof the casing2form an angle between them, preferably of between 110° and 140°, more preferably between 120° and 130°, for example of 125°, so that the device D follows the convexity of the filter cup C when mounted on the mask1. The upwardly extending section2apreferably has a tapered shape, for example an ogive shape. Preferably, the inlet port IN with the at least one sensor4and the outlet port OUT are located in correspondence with the section2aof the casing, while the extraction fan3and the exhalation valve7are arranged in the volume defined by the section2aof the casing2. The command and control unit5, the battery6, the memory unit and the radiofrequency communication module9(if present) are instead preferably arranged in the volume defined by section2bof the casing2.

The casing2preferably has an overall height (measured as the height of its projection on a plane substantially parallel to the section2a) of between 90 mm and 110 mm, more preferably between 95 mm and 100 mm, for example 97 mm. The casing2also has a width (measured as the maximum width of its projection in the above plane) between 35 mm and 50 mm, more preferably between 40 mm and 45 mm, for example 43 mm.

The weight of the device D as a whole is preferably between 20 g and 70 g, more preferably between 45 g and 50 g, for example 47 g.

According to an embodiment of the invention, the ventilation device D comprises a supply port (not shown in the accompanying figures), accessible from the outside through the casing2. The supply port is for example of an USB or micro-USB type, and allows the battery6to be recharged and, optionally, it also allows data exchange with the control unit5. Data exchange via the supply port also allows updating of the predefined algorithm run by the command and control unit5. Alternatively the battery may be recharged by electromagnetic induction.

According to an embodiment, the ventilation device D comprises insulating means (not shown in the accompanying figures), integrated in the casing and/or inside it, suitable for protecting all the electronic components of the ventilation device D, for example from high temperatures and humidity. In this way, the entire ventilation device D can be released from the mask1to be sanitized and/or sterilized according to conventional techniques. Advantageously, the sanitized ventilation device D can be reused by attaching it to a new mask1in sterile conditions.

Advantageously, the ventilation device D allows to extract the air from the inner volume V of the mask1and to expel it toward the outside, thereby generating a positive microclimate.

Advantageously, the ventilation device D allows to maximize the filtering action of the mask1avoiding the introduction, during inhalation, of contaminated air into the mask.

Advantageously, the comfort is improved with the ventilation device D mounted on a mask1, because it actively extracts the hot and humid air which is normally trapped within the inner volume V of the mask1, thereby reducing the temperature and internal humidity, and extracting gases generated by the human exhalation such as CO and CO2which, wearing a mask for extended periods, they can lead to turning and headaches, as well as loss of concentration.

Advantageously, the ventilation device D does not worsen the comfort of the mask1because, being attachable to the outer face E of the filter cup C, it does not interfere with breathing in the inner volume V and does not hinder visibility, having a reduced encumbrance and a conformation that follows the convexity of the filter cup C.

Advantageously, considering the overall airflow, the exhalation valve7is positioned after the passage of the airflow generated by the extraction fan3. Under normal operation of the extraction fan3, the exhalation valve7is kept open by the airflow, but when the user inhales the exhalation valve7closes, thereby preventing the entry of contaminated air into the inner volume V. In this way, a proper sealing is ensured, which protects the user and creates a protected positive microclimate, from the inside of the mask up to the exhalation valve7.

Advantageously, the ventilation device D improves comfort in the use of the mask since it reduces the temperature and humidity inside it, thus obtaining a more comfortable perception on the skin. It also reduces condensation, prevents fogging of any worn glasses, and minimizes the air losses of the mask towards the eyes.

Advantageously, once activated, the extraction fan3starts to extract air from the inside of the mask1, directing it toward the outside, reducing the temperature up to 4° C. and the humidity up to 40%, increasing the comfort for the user wearing the mask1.

Advantageously, the integrated sensor allows to adapt the operation of the extraction device D with respect to the conditions of use of the mask1and to the conditions of the user, adapting automatically to its requirements and to the climatic condition. A climatic condition that can be determined by the radiofrequency connection with the external device10.

The present invention also relates to a ventilation system S shown in the accompanying drawings.

The ventilation system S comprises a filtering mask1comprising a filter cup C provided with an inner face I defining an inner volume V and intended to face the face of a person when in use. The filter cup C is provided with an outer face E, opposite to the inner face I, intended to face outwards when in use. The filter cup C is provided with an opening O for placing the inner volume V in fluid communication with the outside.

The ventilation system S comprises a ventilation device D as described above. The ventilation device D is removably coupled to the outer face E of the filter cup C.

The ventilation system S also comprises an internal fastening element8engaged in the opening O at the inner face I of the filter cup C and removably engaged with the inlet port IN through the opening O, to keep the ventilation device D removably engaged on the outer face E of the filter cup C. This allows the mask1to be replaced by reusing the ventilation device D several times. Moreover, the same ventilation device D can be used with various types of mask1since its operation is dynamic. In fact, the command and control unit5regulates the speed of the extraction fan3according to the physical quantities detected by the sensors4. In fact, the at least one sensor4is configured to detect a value of the physical quantity at the inlet port IN, which it is indicative of the value of the same physical quantity in the inner volume V. This advantageously allows to have a proper exchange of air inside the filter cup C during the use of the mask1.

Preferably, the inner fastening component8is shaped as a ring which screws on the inlet port IN through the opening O, so as to generate a removable and fluid-tight connection (FIGS.4and4a). Alternatively, the removable and fluid-tight coupling between the inlet port IN and the inner fastening element8can be made by bayonet coupling, or by other coupling systems of known type.

According to a preferred embodiment of the ventilation system S, the mask1can be of the cup type, of the filter blade type or silicone cup type with filter insert. Preferably, the inner volume V has a maximum value ranging from 100 cm3to 200 cm3when the mask1is kid-sized, or a maximum value ranging from 200 cm3to 300 cm3when the mask1is small adult-sized, or a maximum value between 300 cm3and 450 cm3when the mask1is large adult-sized, or a maximum value between 450 cm3and 700 cm3when the mask1is of the half-face type, or a maximum value between 700 cm3and 1000 cm3when the mask1is of the full-face type. Advantageously, thanks to the positioning of the ventilation device D on the outer face E of the filter cup C, it is possible to use a mask of smaller dimensions than the known masks.

According to an embodiment of the ventilation system S, the ventilation device D comprises a radiofrequency communication module9, in signal communication with the command and control unit5and configured to communicate with an external device10, such as a smartphone, a smartwatch, a tablet or a PC (see the block diagram ofFIG.8). Preferably, the ventilation system S comprises a predefined application11executed by the external device10. The command and control unit5is configured to communicate with the external device10, executing the suitable predefined application11, configured to receive and process the data collected by the command and control unit5. Always preferably, the predefined application11is configured to send instructions to the command and control unit5to remotely control the operation of the extraction fan3. More preferably, the predefined application11has access to the GPS module of the external device10to geo-locate the ventilation device D. Even more preferably, the predefined application11obtains environmental data concerning the air quality at the geographical position of the ventilation device D. In addition, the predefined application11processes the environmental data and data received from the command and control unit5to regulate the operation of the extraction fan3. Moreover, the application11may generate results and graphs which can be displayed by the graphical interface of the external device10, indicating in real time the operation of the ventilation device D and its filtration efficiency, as well as the quality of the air breathed by the user wearing the mask1.

With reference toFIGS.2and2a, it has to be noted that air passes through the filter by entering the inner volume V through the outer face E of the filter cup C, thereby removing polluting particles or microorganisms such as viruses and bacteria. Meanwhile, the air is of course inhaled by the person. The air contained in the inner volume V exits through the inlet port IN of the ventilation device D when the exhalation valve7is open, possibly with the aid of the extraction fan3when the latter is in operation. Then, the exhausted air is expelled outside through the outlet port OUT of the ventilation device D, carrying heat and moisture due to breathing.

The present invention also relates to a method for controlling the ventilation device D described above. An embodiment of the method will be now described in further detail with reference to the flow chart ofFIG.9.

The user first of all wears the mask1having the ventilation device D attached thereto (step100).

Once the device D is turned on (operation that can be performed by pressing a suitable push-button), the method includes the step of detecting local pressure values at predefined time intervals using the at least one pressure sensor4(step101). The predefined time intervals are preferably comprised between 0.1 sec and 0.3 sec, for example 0.2 sec. It should be noted that device D can be switched on before or after wearing the mask.

The extraction fan3is then switched on automatically (step102). As described above, this can for example occur when it is determined that the local pressure value detected by the at least one pressure sensor4has exceeded a predefined threshold value.

The method further comprises the step of processing, by means of a predefined algorithm executed by the command and control unit5, the pressure values detected at predefined time intervals by the at least one pressure sensor4, for calculating a respiratory frequency value (step103).

In addition, the method includes the step of controlling by means of the command and control unit5the dynamic operation of the extraction fan3as a function of the respiratory frequency value calculated in the previous step (step104). For example, the command and control unit5, in which a predefined algorithm resides, increases the rotation speed of the extraction fan3when it detects an increase in the respiratory frequency and reduces the rotation speed of the extraction fan3when it detects a decrease in respiratory frequency. According to an embodiment, in order to perform this dynamic regulation, the command and control unit5may be configured with a discrete set of predefined values of the rotation speed V1, V2, . . . , VN, each value corresponding to a predefined range of the respiratory frequency value. Each calculated respiration frequency value is compared with these ranges and, if it falls within one of them, the rotation speed of the fan3is set to the corresponding predefined value. This is particularly useful for ensuring correct breathing, while ensuring a filtering of the inhaled air, when the user wearing the mask1is carrying out physical activity.

The fan3is then turned off when the sensors4detect the termination of respiratory activity as the mask1is no longer in use (step105). As described above, according to an embodiment this can occur when it is determined that the local pressure value detected by the at least one pressure sensor4has fallen below the predefined threshold value.

Optionally, the ventilation device D can be configured to also support a manual operating mode, which allows the user to manually adjust the rotation speed of the extraction fan3.

With reference to the flow chart ofFIG.10, according to this manual mode, the user puts on the mask (step110) and, once the ventilation device D has been switched on, presses a push-button (step111) which controls the switching on of the extraction fan3(step112). The user may then control the rotation speed of fan3by pressing the same push-button again. To allow this manual regulation, the command and control unit5may be configured with a discrete set of predefined rotational speed values (for example 30% Vmax, 60% Vmax, 100% Vmax and 0% Vmax, where Vmax is the maximum rotation speed). Each time the button is pressed, the command and control unit5increases the rotation speed of the fan3from one predefined value to the next one. The fan3can also be stopped manually, by pressing the push-button until the rotation speed returns to the predefined value 0% Vmax.

Clearly, the method of the present invention may also be used for the ventilation system S of the present invention, as will be apparent from the following example of application of the method.

With reference to the flow charts ofFIGS.11and12, the interaction between the ventilation device D and the predefined application11executed by the external device10according to an embodiment of the present invention will be described in further detail.

The method provides for switching on the ventilation device D (step121), by pressing a suitable push-button.

The user then wears the mask (step122).

The method then provides for acquiring the respiratory signals by means of the sensors4and processing them by means of the command and control unit5, and finally storing them on the memory unit (step123).

The method provides for automatically activating the extraction fan3by means of the command and control unit5when certain conditions are met as regulated by the predefined algorithm executed by the command and control unit5(step124). The method also provides for recording the usage time of the ventilation device D and/or the operating time of the extraction fan3by means of the command and control unit5, and to store these time parameters in the memory unit (step125).

The method provides for sending, to the external device10executing the predefined application11, the time parameters relating to the usage time of the ventilation device D and to the operating time of the extraction fan3(step126). The method therefore provides for processing the above-mentioned time parameters by means of the predefined application.

The method also provides for detecting the respiration frequency pattern by means of the sensors4, and for sending this parameter to the external device10, by means of the command and control unit5, to be processed by the predefined application11.

The method provides for adjusting the rotation speed of the extraction fan3as a function of the detected respiratory frequency.

The predefined application11therefore receives the time data (step131) and the detected respiratory frequency pattern (step132).

The method provides for recovering by the predefined application lithe data relating to the geographical position and activity of the person wearing the mask1by means of the GPS module of the external device10(step133). For example, in addition to geo-location, it is possible to monitor the displacements and the speed of the person wearing the mask1to determine, for example, whether she/he is walking, or stationary, or doing sports, or traveling by car.

Moreover, the method provides for recovering, by means of the predefined application11, the air quality data at the detected geographical position, by means of the connection to the Internet network of the external device10(step134).

The method provides for processing, by means of the predefined application, data relating to the usage time of the ventilation device D, to the air quality, to the geo-location and to the respiration frequency, to calculate the quantity of pollutants filtered by the mask1over a given time interval (step135).

The method provides for displaying the data relating to the parameters processed on the graphical interface of the external device10(step136).

FIGS.13and14show two exemplary screenshots of the graphic interface of the external device10, through which the parameters processed by the application11are presented.

For example, the screenshot ofFIG.13shows the instantaneous value of the detected respiratory rate (28/min), the current value of the rotation speed of the fan3expressed as a percentage of the maximum rotation speed (65%), and a graph of the pattern of the respiratory frequency over time, during the current session of use of the mask.

The screenshot inFIG.14, on the other hand, shows a map showing the path that the user is following or has completed, a graph of the respiratory frequency and the numerical value of some parameters relating to the current session of use of the ventilation system S (distance travelled, fan speed and respiratory frequency, air quality and autonomy of the ventilation system, in terms of battery level and/or remaining time before a mask filter change is required).

The method provides for turning off the extraction fan3when the sensors4detect termination of respiratory activity as the mask1is no longer in use.

Optionally, the method may provide for generating a warning by means of the external device10which informs the user that the mask1must be replaced because the recommended period of use of the filter is lapsed.