This invention relates to an air purification and microbiological sanitization system for application to an HVAC system of a railway vehicle, for the removal or reduction of polluting volatile components and pathogens.

In general, within the scope of this description and the appended claims, a pathogen is understood to mean any biological or microbiological agent, such as a bacterium, a virus, a parasite, a prion, a fungus or the like or equivalent, whether proteinaceous or single-cell or multicellular.

“Purification and microbiological sanitization” of the air flow in this description and in the appended claims refers to the operation of subjecting a volume of air to a treatment process in order to damage, kill, sterilize, inactivate or otherwise render harmless a significant majority of the pathogens possibly contained therein, as well as removing as much as possible as many volatile or polluting components contained, suspended in or transported by the air, substantially by carrying out decontamination operations, or so-called partial sterilization, or disinfection, microbiological sanitization, and purification.

“HVAC system” refers to a heating, ventilation, or air conditioning system or a system adapted to perform at least one of the functions listed above.

In the following description, reference will be made for simplicity to use with reference to a coach of a railway vehicle, but, obviously, the invention may be similarly implemented in reference to a coach, or to a part thereof, or to a cabin, of a tram vehicle, metropolitan railway or similar vehicle.

The growing increase in drug resistance due to the abuse of antibiotics (which causes about 700,000 deaths a year worldwide), the emergence of microorganisms with high mortality rate (e.g. tuberculosis, meningitis, etc.), the onset of new pathogens with high pandemic risk (MERS, SARS, Covid-19), added to the decrease in the disinfections of vehicles of means of transport in order to contain operating costs, the slowness of the standard sanitation procedures that are implemented only for train shutdowns for second level maintenance (RO-RG), the overcrowding of the coaches at peak times and finally the current presence of filtering systems with a permissive cut-off (Hepa filters > 0.5 pm), are all risk factors that draw the attention of the inventor to the need to provide means of transport, particularly in the railway sector, with disinfection or microbiological sanitization and air purification systems that may operate continuously with high efficiency.

The object of this invention is to provide such a purification and microbiological sanitization system, and in particular an improved purification and microbiological sanitization system with respect to the prior art.

This and other objects are fully achieved according to this invention by a purification and microbiological sanitization system as defined in the appended independent claim 1.

Advantageous embodiments of the purification and microbiological sanitization system according to the invention are specified in the dependent claims, the content of which is to be understood as an integral part of the description that follows.

In summary, the invention is based on the idea of providing a purification and microbiological sanitization system for a heating, ventilation or air conditioning system of a railway vehicle or the like, the purification and microbiological sanitization system comprising: a casing adapted to define therein a purification and microbiological sanitization chamber and having an inlet opening adapted to allow the inflow of air into the purification and microbiological sanitization chamber and an outlet opening adapted to allow the outflow of air from the purification and microbiological sanitization chamber; at least one light emitting diode adapted to generate a germicidal ultraviolet radiation and to emit said radiation within said purification and microbiological sanitization chamber of the casing; an ionization device adapted to at least partially ionize the air contained within said purification and microbiological sanitization chamber of the casing; and an electronic control unit configured to control the purification and microbiological sanitization system; characterized in that it further comprises an air quality sensor adapted to measure a concentration of particulate matter and a concentration of carbon dioxide in the air at said outlet opening, to generate a respective measurement signal representative of this measurement and to transmit it to said electronic control unit, wherein the electronic control unit is configured to control the radiant power of said at least one light emitting diode as a function of the measurement signal transmitted by the air quality sensor.

By virtue of such a configuration of the purification and microbiological sanitization system, it is possible to ensure adequate purification and microbiological sanitization, or decontamination and purification, of the air inside a coach, including therein the driver's cabin, or the engine driver’s cabin, of a railway vehicle on a continuous basis.

Preferably, the purification and microbiological sanitization system further comprises environmental sensors (humidity, temperature, possibly other volatile organic components) adapted to measure respective parameters and to transmit the result of this measurement to the electronic control unit to optimize control.

In this way, it is possible to continuously monitor the outcome of the purification and microbiological sanitization operation carried out by the purification and microbiological sanitization system and to adjust the control parameters (for example, the radiant power emitted by the at least one light emitting diode with germicidal ultraviolet emission, or the power supply to the ionization device) in order to achieve the desired balance between air quality, level of purification and microbiological sanitization or disinfection and energy consumption of the purification and microbiological sanitization system.

Further features and advantages of this invention will be clarified by the detailed description that follows, given purely by way of non-limiting example in reference to the accompanying drawings, wherein:

Fig. 1 is a perspective view in partial section of the purification and microbiological sanitization system according to an embodiment of the invention;

Fig. 2 is a schematic side view of a railway vehicle to which the invention may be applied; and

Fig. 3 is a schematic block view of the purification and microbiological sanitization system of Fig. 1, wherein the blank arrows indicate the direction of the flow of air that is sanitized and purified.

With reference to the figures, the purification and microbiological sanitization system according to the invention is generally indicated with 10. The purification and microbiological sanitization system 10 is adapted to be applied to a heating, ventilation or air conditioning system 12 of a railway vehicle V, or to a single coach C of said railway vehicle V.

The purification and microbiological sanitization system 10 according to the invention essentially comprises a casing 14, at least one light emitting diode LED, an ionization device 16, an electronic control unit ECU, and an air quality sensor 18.

The casing 14 is made as a hollow body, preferably with a tubular or conduit structure, essentially in the form of a frame, or a housing.

Preferably, the casing 14 is made of a non-magnetic metallic material, even more preferably of aluminium.

In the embodiment shown in Fig. 1, the casing 14 is made in the form of a rectilinear conduit with a quadrangular section, but it is not excluded that it may take on different shapes, with a lattice of parallel inner conduits, or in particular that it may comprise a duct of the heating, ventilation or air conditioning system 12 of the railway vehicle V.

The casing 14 is adapted to define therein a purification and microbiological sanitization chamber 20, and has an inlet opening 22 adapted to allow the inflow of air into said purification and microbiological sanitization chamber 20 to be sanitized and purified, or decontaminated, and an outlet opening 24 adapted to allow the outflow of sanitized and purified, or decontaminated, air from said purification and microbiological sanitization chamber 20.

Inside the casing 14 a flow of air to be sanitized and purified, or decontaminated, is made to flow, in a manner known per se, according to the flow direction indicated by the blank arrows in Fig. 3.

Advantageously, the purification and microbiological sanitization chamber 20 is internally coated at least partially with a material reflecting UV-C ultraviolet radiation, such as, for example, Teflon.

Advantageously, at least one filter 26 may be arranged at the inlet opening 22 so as to carry out a first mechanical filtering of the air entering the purification and microbiological sanitization chamber 20. Preferably, this filter 26 may be classified as category G4 according to regulatory standard EN 779:2012.

The at least one light emitting diode LED is adapted to generate a germicidal ultraviolet radiation and to emit it within the purification and microbiological sanitization chamber 20 of the casing 14. This germicidal ultraviolet radiation has a wavelength between 100 and 300 nanometres, preferably between about 255 nanometres and about 300 nanometres. In a manner known per se, the ultraviolet radiation of the UV-C type has a particular germicidal efficacy, that is it is suitable for killing or inactivating any microbiological pathogens present in the air, since these wavelengths are those having the greatest absorption by nucleic acids: the absorption by nucleic acids of this radiation may cause genetic defects, including the formation of pyrimidine dimers, which may prevent the replication of the nucleic acid and the expression of the proteins necessary for the life cycle of the microorganism, resulting in direct death or inactivation of the microorganism.

As may be seen in Fig 1, the purification and microbiological sanitization system 10 may also comprise a greater number of light emitting diodes LEDs; in the example shown, there are four panels each comprising a plurality of light emitting diodes LED (up to 144 light emitting diodes LED in total) emitting germicidal ultraviolet radiation, the four panels being respectively arranged on four internal walls of the casing 14, inside the purification and microbiological sanitization chamber 20. In a manner known per se, the presence of a plurality of light emitting diodes LED allows the appropriate germicidal efficacy to be maintained even in the event of failure of one thereof, ensuring the necessary redundancy.

In the embodiments of the invention which comprise a plurality of light emitting diodes LED, the arrangement of the same light emitting diodes LED, possibly grouped into modules, is obtained in such a way as to maximize the reflective effect of the germicidal ultraviolet radiation UV-C emitted thereby and thus to maximize the radiant power that reaches the inner volume of the purification and microbiological sanitization chamber 20.

In any case, the arrangement of the at least one light emitting diode LED is such as to ensure that the emitted radiation reaches for the most part the purification and microbiological sanitization chamber 20 and is not dispersed inside the coach C of the railway vehicle V, where it could be a source of danger for the crew or passengers.

The ionization device 16 is adapted to at least partially ionize the air contained inside the purification and microbiological sanitization chamber 20 of the casing 14, and is arranged accordingly. The ionization device 16 produces negative ions, which aid in the removal of gases, aerosols, allergens, and polluting particles. In effect, these negative ions bind to the particles present in the air and dispersed therein, such as dust, particulate matter, pathogens (or fragments thereof following exposure to germicidal ultraviolet radiation), pollen, causing them to deposit on inner surfaces of the casing 14. In particular, the ionization device 16 is adapted to ionize through at least partial reduction the ionisable compounds (dust, pollen, etc.) present in the air contained within said purification and microbiological sanitization chamber 20 of the casing 14.

In a preferable embodiment, the ionization device 16 is adapted to ensure the generation of about 2000-4000 ions/cm ³ , so as to obtain an optimal balance between air purification and energy demand. The ionization device 16 further generates a small fraction of ozone (about 0.1 ppm). As may be seen in Fig. 1, the ionization device 16 is arranged within the purification and microbiological sanitization chamber 20, but nothing prevents its arrangement from being different, as long as it is possible to ensure partial but sufficient ionization of the air contained in the purification and microbiological sanitization chamber 20.

In any case, the arrangement of the ionization device 16 is such as to ensure that the ionized air is for the most part that contained in the purification and microbiological sanitization chamber 20 and not that present inside the coach C of the railway vehicle V, where it could be source of danger for the crew or passengers.

Lastly, the purification and microbiological sanitization system 10 may also comprise a greater number of ionization devices 16, without thereby departing from the scope of the invention.

All components of the purification and microbiological sanitization system 10 that require electrical power to operate, including the at least one light emitting diode LED, the ionization device 16 and the electronic control unit ECU, are preferably powered by connection to the electrical power supplied to said railway vehicle V by an auxiliary voltage supply line, in turn supplied by a voltage line L through a conventional pantograph P. Alternatively, it may be possible to arrange such components for the electrical supply from a battery or from a fuel cell, in a manner known per se and thus not shown or described in detail.

The air quality sensor 18 is adapted to measure a concentration of particulate matter and a concentration of carbon dioxide in the air at said outlet opening 24, to generate a respective measurement signal Sp representative of said measurements and to transmit it by means of data transmission means (known per se, not shown) to the electronic control unit ECU. These data transmission means may alternatively be wired or wireless.

Preferably, the air quality sensor 18 comprises a multichannel optical sensor, which allows the continuous and simultaneous determination of the total particulate matter, the PM 10 particulate fraction, the PM4 particulate fraction, the 2.5 particulate fraction, and the PM1 particulate fraction, or at least two of the above, in addition to measuring the concentration of carbon dioxide.

Advantageously, the purification and microbiological sanitization system 10 further comprises at least one environmental sensor 28 adapted to measure at least one of either the temperature or humidity of the air within said purification and microbiological sanitization chamber 20, to generate a respective measurement signal Se representative of such measurement and to transmit it to said electronic control unit ECU. In a manner known per se, it is possible to use a plurality of such environmental sensors 28, both to measure the different environmental parameters at different points of the purification and microbiological sanitization chamber 20 and to measure each environmental parameter separately, or, alternatively but in an equivalent manner, it is possible to use a single integrated environmental sensor 28 adapted to measure a plurality of environmental parameters. Lastly, the environmental sensor 28 may also be adapted to sense further parameters, such as the air pressure, or the concentration of other components, such as for example volatile organic components, or any other polluting components.

Advantageously, the purification and microbiological sanitization system 10 further comprises at least one anemometer 30 adapted to measure the air velocity within said purification and microbiological sanitization chamber 20, preferably at or near said outlet opening 24 of the casing 14, to generate a respective measurement signal Sv representative of said measurement and to transmit it to said electronic control unit ECU.

Clearly, it is also possible that the air quality sensor 18, the environmental sensor 28, and the anemometer 30 are made (all or at least two thereof) integrally in a single measurement component.

In a further embodiment, inside the purification and microbiological sanitization chamber 20 there is also a wire mesh filtering device 32, which is heated by means of a dedicated heater, preferably electrically powered, and even more preferably with recovery of the waste heat energy of the at least one light-emitting diode LED, and which is adapted to heat the air contained or passing through the purification and microbiological sanitization chamber 20, preferably up to a maximum temperature of about 55-65°C, only near the grid of the wire mesh. Preferably, this wire mesh filtering device is provided in the form of a resistance wire mesh and is arranged in such a way as to be in contact with metal heat sinks associated with the at least one light emitting diode LED to recover the heat dissipated thereby.

As mentioned above, the purification and microbiological sanitization system 10 further comprises the electronic control unit ECU. Said electronic control unit ECU is configured, or programmed, to control the purification and microbiological sanitization system 10, or at least one of the components that comprise it.

In particular, according to the invention, the electronic control unit ECU is configured to control the radiant power of the at least one light emitting diode LED as a function of the measurement signal Sp received from the air quality sensor 18.

In a preferable embodiment of the invention, the electronic control unit ECU carries out the aforesaid control of the purification and microbiological sanitization system 10, or of at least one of the components that comprise it, by controlling the frequency of the supply current (PWM signal).

Advantageously, the electronic control unit ECU is configured to control the radiant power of said at least one light emitting diode LED as a function of the result of a comparison between the measurement signal Sp transmitted by the air quality sensor 18 and a control value stored in the electronic control unit ECU. The control value may then be a programmed target value, whereby, for example, the radiant power of the at least one light emitting diode LED is increased if the target value has not been reached, and therefore the measurement signal Sp sent by the air quality sensor 18 is indicative that a concentration of particulate matter or a concentration of carbon dioxide is still higher than the target value. Conversely, if, following the outcome of this comparison, the electronic control unit ECU determines that the measurement signal Sp sent by the air quality sensor 18 is indicative of a concentration of particulate matter or a concentration of carbon dioxide sufficiently below the target value, then, preferably, the electronic control unit ECU may be configured to command a reduction in the radiant power emitted by the at least one light emitting diode LED in order to always ensure the minimum use of electrical power, and, therefore, improve the energy efficiency of the purification and microbiological sanitization system 10 as a whole.

Advantageously, the electronic control unit ECU may also be configured to control an electrical power supply to the ionization device 16 as a function of the measurement signal Sp transmitted by the air quality sensor 18.

Advantageously, the electronic control unit ECU may also be configured to control the radiant power of the at least one light emitting diode LED and/or the electric power supply to the ionization device 16 also as a function of the measurement signal Se transmitted from the environmental sensor 28, when present.

Lastly, advantageously, the electronic control unit ECU may also be configured to control the radiant power of said at least one light emitting diode LED and/or to control the electrical power supply to the ionization device 16 also as a function of the measurement signal Sv transmitted by said anemometer 30, when present.

As mentioned above, the purification and microbiological sanitization system 10 is adapted to be applied to the heating, ventilation or air conditioning system 12 of a railway vehicle V, or of a single coach C of said railway vehicle V, as shown in Fig. 2. The system 12 comprises, in addition to the purification and microbiological sanitization system 10 according to the invention, an inflow duct 34 and an outflow duct 36. The inflow duct 34 and the outflow duct 36 are made as conventional ducts of a ventilation, heating or air conditioning system and therefore are not described further in detail.

The inflow duct 34, in any case, is adapted to take in air to be sanitized and purified, or decontaminated, from the coach C of the railway vehicle V and conduct it to said purification and microbiological sanitization system 10, to introduce it into the purification and microbiological sanitization chamber 20 of the purification and microbiological sanitization system 10, through the inlet opening 22. Similarly and in the opposite way, the outflow duct 36 is adapted to reintroduce the sanitized and purified, or decontaminated, air coming from the purification and microbiological sanitization system 10, into the coach C of the railway vehicle V.

In a known manner, the heating, ventilation or air conditioning system 10 may comprise additional ventilation, heating or air conditioning elements, which may be arranged both upstream and downstream of the purification and microbiological sanitization system 10.

Naturally, without prejudice to the principle of the invention, the embodiments and the details of construction may be widely varied with respect to that which has been described and illustrated purely by way of non-limiting example, without thereby departing from the scope of the invention defined by the appended claims.

In particular, the arrangement or position of the component elements of the purification and microbiological sanitization system 10 may be modified without thereby departing from the scope of the invention as defined in the appended claims. It is possible, for example, to arrange, alternatively, the ionization device 16 downstream or upstream of the filter 26, and, similarly, to arrange the at least one light emitting diode LED downstream, concurrently, or upstream of the ionization device 16, it being understood that what is shown in the figures and described in this description constitutes purely exemplifying and non-limiting embodiments of the invention.