PRESENTIN THEAIR

DESCRIPTION

The present patent concerns the sector of devices for filtering and purifying the air and in particular it concerns a new passive device for sucking and filtering the fine particulates present in the air, suited to be installed on moving vehicles like buses, streetcars, taxis or other vehicles that circulate mainly in towns or in any case in places where the concentration of said particulates in the atmosphere is high. The problem represented by the high concentration of particulates in the atmosphere is known and particularly felt, said particulates being constituted by solid or liquid particles suspended in the air, with characteristic diameter equal to or shorter than 10 μm, and being commonly defined PMlO. The origins of the emissions of PMlO are natural, such as erosion of the soil, diffusion of pollen and spores, or anthropic.

In particular, in urban areas, said substances are mainly generated by combustion engines, heating systems, industrial emissions and vehicle traffic. PMlO is extremely dangerous for humans; it causes irritations and inflammations and also more serious and chronic pathologies. Fine particulates, in fact, are easily inhaled and furthermore contain very noxious micropollutants, like heavy metals and aromatic polycyclic hydrocarbons.

PMlO also causes alterations in the physical properties of the atmosphere, like visibility, light reflection and refraction, and also causes the blackening of the external surfaces of buildings and monuments.

Various methods and devices for air treatment are known, designed to abate the contaminating agents and the fine particulates.

Methods and devices are known that are suitable for purifying and removing the dust from the air in environments that are closed or located immediately downstream of the source of contaminants, and are also suitable for limiting the diffusion thereof.

In order to effectively reduce urban atmospheric pollution deriving from the fine particulates produced by vehicle traffic, the use of fixed air filtering and purifying devices is also known, said devices being located in urban environments in the immediate vicinity of roads and busy road junctions, in order to limit the diffusion of fine particulates in the surrounding space.

However, these devices, which help improve the quality of the air in urban environments, pose some drawbacks. First of all, their overall dimensions and visual impact make them unsuitable for use in some specific urban contexts, for example in historical centres.

Furthermore, the use of said devices involves high consumption and high energy costs, and in any case they need to be electrically powered with special electric systems. Furthermore, the known devices are installed in a fixed position, and thus their range of action in the surrounding space is limited.

The subject of the present patent is a new type of passive device for sucking and filtering the fine particulates present in the air, from PMlO to nano- particulate, suited to be installed on moving vehicles like buses, streetcars, taxis, or other vehicles that mainly circulate in city centres or towns or in any case in places where the concentration of said particulates in the atmosphere is high.

The main object of the present invention is to provide a device that sucks and filters the air, reducing its pollution load, for example in terms of fine particulate contents, in particular in city centres or towns, wherein the air intake occurs in a passive manner, that is, through exploitation of the speed of a vehicle, like a bus, a streetcar, a taxi, or a motor vehicle in general, on which the device is installed, thus eliminating the energy costs resulting from the intake process. Another object of the present invention is to provide a movable device, which therefore can be applied to a larger urban surface compared to a fixed device.

Another object of the present invention is to provide a device that can be applied to an urban area that is nearer to the area where the highest quantity of particulates is produced, thus limiting its diffusion in the surrounding environment.

Another advantage of the present invention is represented by the fact that it can be both installed on existing means of transport and integrated in new ones. Another advantage lies in the energy savings, as the speed of the vehicle is exploited, and therefore the installation of intake means is not required; furthermore, the electric energy generated by the electric system of the vehicle itself is used, since the device is powered with low voltage and its power absorption is very low. Another advantage of the present invention is represented by the fact that it optimises the particulate abatement efficiency up to a speed of 70 km/h of the vehicle on which the device is installed, thanks to the use of devices that control the values of the air flow rate entering the device, which must be kept within the optimal rated values that ensure maximum efficiency. These and other direct and complementary objects are achieved by the new passive intake and filtering device for the fine particulates present in the air, suited to be installed on moving vehicles like buses, streetcars, taxis, or other means that circulate mainly in city centres or towns. The new device is suited to be installed on or integrated in a vehicle and comprises one or more air filtering means, at least one air intake, arranged at the front with respect to the normal running direction of the vehicle, and at least one outlet for the expulsion of the filtered air flow. Said new device is thus suited to be applied preferably on the roof of urban means of transport like buses, streetcars, public service vehicles that circulate in city centres and towns, or in any case in the areas that are most affected by pollution due to particulate matter resulting from vehicle traffic. Said devices, installed on said means of transport running on city roads, suck in the air loaded with fine particulates through said air intake. The flow of sucked air is conveyed through the filtering means and then is discharged into the atmosphere through said air outlet, which is preferably arranged at the back of the device with respect to the vehicle's normal running direction.

In greater detail, according to the invention said filtering means comprise a first filter made of a filtering fabric, for example a fabric preferably in class F8, capable of retaining particulates up to 4 μg in size. Said filtering fabric is preferably wound in at least two coils, of which one is a powered rewind coil, suited to rewind the fabric when the portion struck by the air flow to be filtered has been consumed, and the other is a loading coil, preferably with braked or idle rotation, on which there is the filtering fabric to be unwound.

At least one optical opacity reader measures the degree of clogging of the fabric, thus automatically controlling the translation and rewinding of the fabric itself when necessary. According to the invention, at the back of said fabric there is at least one rigid or semi-rigid holed support, suited to maintain said fabric stretched in order to guarantee optimal filtering results.

Said filtering means also comprise, downstream of said filtering fabric, one or more electric filters or electrostatic cells powered with low voltage, capable of guaranteeing filtration of particles with characteristic size down to nanometres.

A further shaped filtering fabric can be conveniently arranged between said filtering fabric in coils and one or more electric filters or electrostatic cells powered with low voltage. In the preferred embodiment of the invention, the new device comprises a frame for containing said components, shaped so that it can be installed on the roof of said moving vehicles.

Said containing frame is preferably a casing made of fibreglass or another suitable material with limited weight, suited to protect the internal components and to favour air outflow. According to the invention, the external surface of said casing can also be conveniently used for application, for example, of advertising or informative panels.

Said panels also serve to cover, protect and hide the device installed on the roof of the vehicle. Alternatively, said device is suited to be integrated in said moving vehicle, and said air intake can be conveniently located on the front of the vehicle, facing towards the running direction of the vehicle itself, for example laterally and/or on the roof of the vehicle and/or on the lower part of the vehicle. The new device also comprises at least one system for controlling the flow rate of air to be filtered entering said filters, in order to optimise their efficiency.

In fact, the efficiency of the filtering means in reducing the fine particulate is a function of the incoming air flow rate, wherein as the flow rate increases due to the increase in the speed of the incoming air, the filtering efficiency decreases, as shown in the diagram of Figure 1.

In particular, said control system has the function to maintain high abatement efficiency values of the filters, said efficiency values exceeding 93% up to incoming air speeds in the order of 70 km/hour, which corresponds to the speed of the vehicle.

Once this speed has been exceeded, the filtering efficiency decreases. In the preferred embodiment of the invention, the new device comprises a first "labyrinth" system for controlling the incoming air flow to be filtered, positioned upstream of the filtering means, downstream of and in proximity to said air intake. Said first "labyrinth" control system comprises one or more partitions arranged crosswise to the direction of the incoming air flow, said air being conveyed along a coil-shaped path.

At least one of said partitions is flexible towards an adjacent partition or a wall, wherein said partition bends due to the thrusting effect of the incoming air when its speed exceeds an established limit value, for example 40 KnVh. The bending of said partition towards the adjacent partition or said wall reduces the cross section through which the incoming air passes, thus controlling the flow rate, which must be constantly kept at optimal rated values.

According to the preferred embodiment of the invention, the new device also comprises at least one further control system or compensator or optimizer of the speed of the air entering the device, suited to control the flow rate of the air to be treated by said filters to reduce the fine particulates. Said compensator or optimizer, made of reticular steel fibres, is installed upstream of the electrostatic filtering cells and has the function to distribute the air to be treated so that all the cells treat the same quantity of air. According to the invention, at the level of said air intake and of said air outlet opening/closing gates are installed, each controlled by at least one low voltage motor.

According to the invention, the new device is electrically powered by the electric system of the vehicle.

In the preferred embodiment of the invention, electric filters are used which absorb very low power, for example 12W each, thus requiring a low voltage, 24V, supplied by the electric circuit of the vehicle. The power absorption of the entire device is very low, approximately 36 W, which means practically inexistent energy costs.

Furthermore, on streetcars or other electrically powered vehicles or vehicles with electric motor it is also possible to install more than one device, even with higher power, thus treating even higher quantities of air and further minimizing the environmental impact.

According to the invention, the device can be operated by means of a special switch or control, or directly by starting the vehicle.

For example, said new device can also be connected to the vehicle's key switch, so that when the operator turns the key, he/she activates the device at the same time.

According to the invention, the new device may also comprise at least one rain sensor that, in case of atmospheric precipitation, transmits a signal to said motor of said gates of the air intake and outlet, in such a way as to close them, avoiding the infiltration of water in the filtering systems and preventing the deactivation of the device or the electric filters only.

In further detail, in case of rain said rain sensor controls, in order, the deactivation of said electric filters, the closing of said gate of the air intake and the closing of said gate of the air outlet. When said sensor detects that the atmospheric precipitation has ended, it authorizes the opening of said gates and reactivates said electric filters.

As an alternative to the rain sensor, to close and open said gates it is also possible to use, in combination, the vehicle's windscreen wiper switch.

Assuming, for each device, an average flow rate of filtered air equal to approximately 11.500 m ³ /h, and considering a vehicle like a city bus that during one day remains in function for 19 hours, the quantity of filtered air is equal to approximately 218.500 m ³ .

If we suppose to install the system on 50 buses, the quantity of air filtered in one day will be approximately 10.925.000 m ³ , and therefore approximately 327.000.000 m ³ in a month of 30 days.

The new device may also be installed on smaller vehicles, for example minibuses, thus treating smaller flow rates of air, for example approximately

6000 m ³ /h.

On the other hand a smaller device, if installed on service vehicles, for example on the bars positioned on the roof, can treat air flow rates up to

4000 m ³ /h.

Therefore, the new device can treat enormous quantities of air at very low costs.

According to the invention, in order to allow the filters to be cleaned, serviced and replaced, the filter unit described above is positioned on rails or on an extractable slide, so that it is possible to translate the filter unit outside the casing and proceed to partially or completely cleaning, servicing or replacing the filters.

The characteristics of the present invention will be highlighted in greater detail in the following description, with reference to the enclosed drawings, attached as examples without limitation.

Figure 1 shows the efficiency diagram of a filter such as, in particular, an electrostatic cell or electric filter (D), as a function of the air flow rate to be treated and of the vehicle speed. Figure 2 is a schematic representation of a side view of the new device (Z) installed on the roof of a bus (1), while Figures 3 a and 3b show a schematic representation of the device (Z) in a three-dimensional and a side view, respectively.

According to a possible embodiment of the invention shown in Figures 3a and 3b, the new device (Z) comprises a frame or containing body (U) suited to be installed, for example, on the roof of a moving vehicle (1), like a bus, a streetcar or other means for transporting persons and/or goods that circulates mainly in city centres or towns or in any case wherever the concentration of fine particulates in the atmosphere is particularly high. Said frame (U) comprises at least one air intake (A), positioned at the front

(11) of the device with respect to the normal running direction (X) of the vehicle (1), indicated by an arrow in Figure 2.

At the level of said air intake (A) there is at least one closing gate (B) controlled by at least one low voltage motor (T). The new device also comprises at least one system (V, Q) for controlling the flow rate of incoming air to be filtered (Wi), in order to optimize the efficiency of the filtering means (C, D).

The new device comprises a first "labyrinth" system (V) for controlling the flow rate of incoming air to be filtered (Wi), arranged upstream of the filtering means (C, D), downstream of and in proximity to said air intake

(A).

Said first "labyrinth" control system (V) comprises a plurality of partitions (Vl, V2, V3) arranged crosswise to the direction of the incoming air flow (Wi), which is conveyed along a coil-shaped path, as schematically shown in detail in Figure 4a. At least one of said partitions (Vl), preferably the first one, is flexible towards the adjacent partition (V2), wherein the bending of said partition (Vl) is caused by the thrust of the incoming air flow (Wi) when its speed exceeds known values, as schematically shown in detail in Figure 4b. The bending of said partition (Vl) towards the adjacent one (V2) reduces the cross section (Vq, Vq') through which the incoming air flow (Wi) passes, thus controlling the flow rate.

The new device comprises one or more means (C, D) for filtering the incoming air (Wi), more precisely a first filter, schematically shown in Figure 5 and made of a filtering fabric (C), and one or more electric filters or electrostatic cells (D), schematically shown in Figure 6. Said filter made of filtering fabric (C), located downstream of said first "labyrinth" system (V) for controlling the air flow rate, comprises a fabric tape (Cl) wound in two coils (C2, C3), of which one is a rewind coil (C2) connected to at least one motor (O) and suited to rewind the fabric tape (Cl) when the portion struck by the air flow (Wi) to be filtered has been consumed, and the other is a loading coil (C3), preferably with braked or idle rotation, on which the filtering fabric tape (Cl) to be unwound is wound. According to the invention, the device comprises also at least one optical opacity reader (P) suited to measure the degree of clogging of the fabric (Cl), thus automatically controlling the rewinding of the fabric (Cl) when necessary. Always according to the invention, in a position at the back of said fabric tape (Cl) there is at least one rigid or semirigid support (C4), suited to maintain said fabric (Cl) stretched, in order to guarantee optimal filtering results.

The new device also comprises at least one compensator or optimizer (Q) of the incoming air (Wi), suited to control the flow rate of incoming air, said compensator or optimizer (Q) being arranged downstream of said filter made of filtering fabric (C).

Said compensator or optimizer (Q) is made of reticular steel fibres.

The new device comprises one or more electric filters or electrostatic cells

(D) located downstream of said compensator or optimizer (C) and arranged for example side by side with respect to the incoming air flow (Wi), as schematically shown in Figure 6.

Downstream of said electric filters (D) there is at least one ejector (E) and one outlet (F) for the ejection of the filtered air flow (Wu), said ejection outlet (F) being preferably positioned at the back (12) of the device with respect to the normal running direction (X) of the vehicle (1).

At the level of said ejection outlet (F) of the filtered air (Wu) there is at least one opening/closing gate (S) controlled by at least one low voltage motor

(R).

According to the invention, the new device may also comprise at least one rain sensor (G) that, in case of precipitation, causes said electric filters (D) to be deactivated and said gates (B, S) of the air intake (A) and air outlet (F) to be closed.

The new device (Z') may also be smaller and suitable for installation on service vehicles (2), for example on the bars (21) mounted on the roof of the vehicle (2), as shown in Figure 7, obviously treating smaller air quantities. According to the invention, the outer surface of said frame (U) may also be conveniently used for applying, for example, panels (N) for advertising or informative purposes.

Figures 8a and 8b show the preferred embodiment of the invention which, between said layer in filtering fabric (C) on coils (C2, C3) and said electrostatic filters (D), comprises a further filtering layer, consisting of a filtering fabric (K) arranged in a zig-zag pattern to increase the filtering surface. The entire filtering unit is placed on a counterframe (CT) provided with sliding guides or rails (GR) for the extraction of the filtering systems. Finally, two circumferences (J) indicate the position of application of two axial aspirators, to be preferably activated automatically should the vehicle (1) need to be parked.

Therefore, with reference to the above description and the attached drawings, the following claims are expressed.