Patent Application
20170159435
The present invention is generally applicable to the technical field of the civil engineering and it particularly relates to a system for filtering the fresh air flowing in a tunnel and/or the exhaust gases flowing out therefrom, the tunnel being particularly of railway, road or motorway type.
More particularly, the invention allows to filter the exhaust gases and/or the fresh air through high pressure atomized water, starting from 150 bar.
As known, in case of fire, gas leak or similar accident in a road, motorway or railway tunnel exhaust gases develop being potentially harmful for people near the concerned area.
In fact, by its nature, the exhausted gases move quickly, and may potentially contaminate a very huge area.
Then, in case of such events, there is the need to insulate the area concerned by the accident without creating loss of inlet or fluid-dynamic disorders, to limit as much as possible the consequences thereof, and/or to create an escape for people being in the surrounding areas.
The existing security systems generally act upon the cause of the accident but not upon its consequences. For example, the fire protection systems tend to put out the fire but have no effect on the exhaust gases developing therefrom.
From the Japanese patent application JP2004313753 an example of such security systems is known, which does not mention in any way the treatment of the exhaust gases as a consequence of an accident.
Even in the case of normal vehicular traffic there is still the need to treat the exhaust gases which develop in a tunnel, for example to abate the so-called fine dust (ie, powders having generally an average diameter lower than 10 μm), known to be harmful to human health, or the malodorous substances and/or unburnt particles therein.
From the European patent application EP1544408 a system for the evacuation of exhaust gases from a tunnel is known that includes the washing thereof through spurts of water to decrease the temperature. This document does not specify either the working pressure or the diameter of the water drops.
Furthermore, in the case of fresh air flowing in the tunnel there is the danger that dirt and/or foreign bodies enter in the ventilation duct of the tunnel, obstructing it.
Object of the present invention is to at least partially overcome the above mentioned drawbacks by providing a system that allows to filter the exhaust gases flowing out from a tunnel and/or fresh air flowing therein, for example a road, motorway or railway tunnel, in a safe, effective and economic manner.
Another object of the invention is to provide a system to filter the exhaust gases flowing out from a tunnel and/or fresh air flowing therein having minimal environmental impact.
Another object of the invention is to provide a system that allows to filter the exhaust gases flowing out from a tunnel and/or fresh air flowing therein with minimum inlet losses.
Another object of the invention is to provide a system to filter the exhaust gases flowing out from a tunnel and/or fresh air flowing therein which is simple to manufacture.
Another object of the invention is to provide a system to filter the exhaust gases flowing out from a tunnel and/or fresh air flowing therein that has a relatively high time duration.
Another object of the invention is to provide a system to filter the exhaust gases flowing out from a tunnel and/or fresh air flowing therein that requires a minimum maintenance.
These objects, and others which will appear more clearly hereinafter are fulfilled by a system having one or more of the features herein described and/or claimed and/or shown.
Advantageous embodiments of the invention are defined in accordance with the appended claims.
Further features and advantages of the invention will become more evident reading the detailed description of some preferred not-exclusive embodiments of a system 1, which are shown as non-limiting example with the help of the annexed drawings wherein:
With reference to the above mentioned figures, the system according to the invention, generally indicated with 1, is particularly useful for the filtration of exhaust gases flowing out from a tunnel T, for example the exhaust gases that develop as a result of a potentially dangerous accident, such as a fire or a gas leak, or the exhaust gases that develop in the tunnel as a result of vehicular traffic, whether it is more or less intense.
Certainly, the exhaust gases have a nature and a different composition due to the cause that generates them.
Generally, such exhaust gases direct a solid phase with more or less fine grains, nevertheless being always of micrometric size.
In case of fire, the exhaust gases may include a solid coarse phase, which normally consists of soot and possibly other coarse particles, and a solid fine phase, which normally consists of the so-called fine dust or PM10 (ie powders having generally an average diameter equal to or lower than 10 μm).
The solid coarse phase is generally formed by particles of an average diameter greater than 10 μm, usually up to 100 μm.
On the other hand, in the case of intense vehicular traffic the exhaust gases may comprise the only solid fine phase.
In any case, particularly if the tunnel is placed near an urban centre, there may be the need to abate the polluted unburnt particles and/or the malodorous substances of the exhaust gases.
The system 1 may be configured to abate from the exhaust gases one or more of the solid or fine phases or of the polluted unburnt particles and/or the malodorous substances above mentioned.
Furthermore, the system 1 may be useful to filter the fresh air flowing in the tunnel T, so as to prevent dirt and/or foreign bodies to enter therein.
Advantageously, the system 1 may be used in a tunnel T that stands above a roadway R, for example, a road tunnel, a motorway or a railway.
The system 1 may comprise one or more ports 300 fluidly connected to the outer environment A and one or more ports 310 fluidly connected to the tunnel T.
Depending on whether the system 1 is used for the filtration of the fresh air flowing in the tunnel T or for the exhaust gases flowing out from the tunnel T the one or more ports 300, 310 act as inflow or outflow for the filtered/to be filtered fluid.
Furthermore, the system 1 may comprise filtering means 20 interposed between the one or more ports 300, 310 and lying on the fluid line connecting them.
In a first embodiment, the system 1 may comprise detecting means of the accident having at least one sensor element, such as a fire sensor 10 or a fine dust sensor 10′ or an unburnt particles and/or malodorous substances sensor 10″, which may or may not be placed in the tunnel T, as appropriate. Then, alarm means may be provided, for example an alarm and/or a warning light 11.
Furthermore, control means 30 may be provided operatively connected to the detecting means and the filtering means to activate the latter in response to the detection of the potential danger of pollution by the former.
In a first embodiment, the control means may be manual, for example a lever or a button 30 that an operator manually activates once the sensor has detected the situation of potential danger and has set off the alarm 11.
However, to ensure maximum safety for the operators, the control means may be operable at distance with respect to the tunnel T. For example, an operations' station 31 may be provided spaced apart from the tunnel, wherefrom the operator may activate the button 30.
In this case, both the detecting means and the filtering means should be remotely connected to the operational centre 31, for example by wires or a wireless connection. In this way, the operator, once alerted by the alarm 11, may safely activate the filtering means.
Furthermore, to ensure the maximum rapidity of intervention, the control means 30 may be configured to automatically activate the filtering means 20 in response to the detection of the situation of potential danger. In this case, the treatment of the exhaust gases takes place in a totally automatic manner and without the need of operators.
Advantageously, as shown in
In this way, in case of fire it is possible to secure the upstream or downstream area of the section of the tunnel T where the same fire has occurred. In this way, it is possible to evacuate people safely and quickly, as well as to create a safe area for the means and the people involved in the rescue and recovery of the concerned area.
Suitably, as schematically shown in
Preferably, the average diameter of the drops of atomized water may be lower than 250 μm, while the minimum working pressure may be of 200 bar.
Suitably, furthermore, the nozzles 24 may be of stabilized flow type, manufactured according to the teachings of the patent application VI2014A000047.
Furthermore, to allow the water supply from the reservoir 21 to the nozzles 24 a line of fluid connection 25 may be provided passing through the pumping means and through the collector or collectors 23.
Moreover, to power supply the latter, the line 25 may include one or more supply pipes 26, one for each collector 23. Each supply pipe 26 may be independently power supplied by pumping means 22.
As shown hereinafter, the filtering means 20 may include one or more filtering units 20′, 20″, 20′″, which may have different functions according to the parameters of the atomized water used.
The high pressure atomized water is extremely effective as filtering means, and it allows to abate completely the soot that is emanated in case of fire or gas leak. Furthermore, it has no environmental impact, and it allows to have reduced inlet losses with respect to the classic sleeve or electrostatic filters.
It is understood that the system 1 may be used for both the above mentioned purposes, that is, for filtering both the fresh air flowing in the tunnel T and the exhaust gases flowing out from the tunnel T.
The same filtering unit 20′ may act both on the fresh air flowing in the tunnel T and on the exhaust gases flowing out from the tunnel T. On the other hand, the system may comprise one or more filtering units 20′, 20″, 20′″ to act upon the fresh air flowing in the tunnel T and one or more filtering units 20′, 20″, 20′″ to act upon the exhaust gases flowing out from the tunnel T.
Advantageously, as shown in
Each transverse ventilation duct may include a first branch R1 for the evacuation of the exhaust gases from the tunnel T towards the outer environment and a second branch R2 for the inflow of fresh air from the outer environment into the tunnel T. As shown in
In a further embodiment, shown for example in
In a known manner, the presence or absence of the transverse ventilation duct and, if present, its configuration depends on the features of the tunnel T, for example on its length, on the traffic that has to carry and on its geographical position.
Suitably, these transverse ventilation ducts TV may include fan means V, of known type, to force the evacuation of the exhaust gases from the tunnel T towards the outer environment and/or the inflow of fresh air from the outer environment towards the tunnel T. To the object, the ventilation means V may be placed in the branches R1 and/or R2.
In a preferred but not exclusive embodiment, the one or more collectors 23 with the relative high pressure nozzles 24 may be inserted in the transverse ventilation duct TV, and in particular in the branches R1 and/or R2.
Advantageously, where the fan means V are configured to force the inflow of fresh air from the outer environment towards the tunnel, the nozzles 24 may be susceptible to prevent the entry of dirt and/or foreign bodies therein.
Preferably, therefore, the nozzles 24 may be placed at the entry of the ventilation duct TV, with the fan means V placed downstream thereof along the forwarding direction of the fresh air from the outer environment A towards the tunnel T. However, there may be more filtering units in series, possibly with more fan means placed between two or more units.
Depending on requirements, the nozzles 24 may spray atomized water continuously, at predetermined time intervals or selectively, for example being controlled by the control means 30. Moreover, there may be a sensor that signals the possible entry of dirt or foreign bodies, possibly activating the nozzles 24 in an automatic way.
Suitably, in this case the average diameter of drops of the water is lower than 400 μm, preferably lower than 300 μm and more preferably lower than 200 μm.
Preferably, the minimum pressure may be of 200 bar, and even more preferably of 250 bar.
This allows to minimize the environmental impact of the filtering means, in addition to a considerable saving of water.
In this case, there may be one or more filtering units, which are identical or different. In the embodiment shown in the figures there is a single filtering unit 20′.
On the other hand, even where the fan means V are configured to force the evacuation of the exhaust gases from the tunnel towards the outer environment there may be one or more filtering units, which are identical or different.
In the preferred but not exclusive embodiment shown in the figures, the filtering means 20 may include more filtering units 20′, 20″, 20′″, fluidly connected in series. Each of them may have a specific function.
In particular, the first filtering unit 20′ may be susceptible to abate the solid coarse phase present in the exhaust gases, the second filtering unit 20″ may be susceptible to abate the solid fine phase (fine dust or PM10) present in the exhaust gases and the third filtering unit 20′″ may be susceptible to abate the malodorous substances and/or unburnt particles present in the exhaust gases.
Each one of the filtering units 20′, 20″, 20′″ may have a respective first, second and third inflow 200′, 200″, 200′″ for the exhaust gases to be treated and a respective first, second and third outflow 210′, 210″, 210′″ for the treated exhaust gases.
Advantageously, the control means 30 may be configured to selectively activate the different filtering units depending on the danger detected by the detecting means.
In particular, the control means 30 may activate all three filtering units 20′, 20″, 20′″ if the fire sensor 10 detects the presence of the first solid coarse phase and in particular of soot.
Since the same generally develops due to the fire, the sensor 10 may be a temperature or opacity sensor, respectively calibrated to give an alarm signal if the temperature or opacity detected exceed a predetermined threshold value. On the other hand, the sensor 10 may be susceptible to detect the presence of the solid coarse phase in a concentration greater than a predetermined threshold value.
Furthermore, the control means 30 may activate the only second and third filtering unit 20″ and 20′″ if the fine dust sensor 10′ detects the presence thereof in a concentration greater than a predetermined threshold value, which is generally fixed by law.
Moreover, the control means 30 may activate the only third filtering unit 20′″ if the unburnt particles and/or malodorous substances sensor 10″ detects these malodorous substances and/or unburnt particles exceeding a predetermined threshold value, which is generally fixed by law.
Suitably, the sensors 10, 10′ and 10″ may be connected together in cascade, so that if the first detects a potential danger the other two can not send signals and so forth.
In a preferred but not exclusive embodiment, the first filtering unit 20′ may include one or more porous laminar elements 220, which for example may be made of nonwoven polyamide or polyester fabric.
The use of the porous laminar element 220 is highly advantageous, since it allows to collect the entire solid coarse phase and in particular the soot, without losses in the exhausting water. To the object, the porosity of the porous laminar element 220 may be chosen so as to retain the solid particles PS and let the water W flow, as schematically shown in
Once exhausted, the laminar element 220 may be replaced by a new one. To the object, the laminar element 220 may be assembled in a removable manner.
Advantageously, the porous laminar element 220 may be placed below the high pressure nozzles 24′ so that the mixture of water and solid coarse phase is collected by gravity thereto. To the object, the laminar element 220 may be assembled on the floor P of the ventilation duct TV or of the filtering units 20′, 20″, 20′″.
In a preferred but not exclusive embodiment, the porous laminar element 220 may have a permeability greater than or equal to 85 l/s m2.
Suitably, the porous laminar element 220 may have a porosity not lower than 85%, with an average pores diameter of 100 μm.
Preferably, the porous laminar element 220 may be of the type susceptible to resist to high temperatures, indicatively with a maximum temperature of use of 210° C.
It is understood that even the other filtering units 20″ and 20′″ may include one or more laminar elements 220, which may be identical to those used for the filtering unit 20′ or different, for example having different porosity.
Advantageously, the exhaust gases and the atomized water flowing out from the first high pressure nozzles 24′ may be in counter-current between them inside the first filtering unit 20′. This allows a high efficiency of abatement of the solid coarse phase.
To selectively abate the solid coarse phase from the exhaust gases, the atomized water has to be sprayed at lower working pressures and into drops having an average diameter greater than the other filtering units 20″ and 20′″.
Therefore, the atomized water flowing out from the first high pressure nozzles 24′ may be in drops of an average diameter of 80 μm to 200 μm and may have a working pressure of 200 bar to 280 bar.
On the other hand, the atomized water flowing out from the second high pressure nozzles 24″ of the second filtering unit 20″ may be in drops of an average diameter of 5 μm to 30 μm and at a working pressure of 250 bar to 350 bar. Suitably, inside the second filtering unit 20″ the exhaust gases and the atomized water flowing out from the second high pressure nozzles 24″ may be in co-current.
Both the first and the second filtering unit 20′, 20″ act physically upon the exhaust gases, respectively abating in a selective manner the solid coarse phase and in particular the soot, and the fine one. To abate the unburnt particles and/or the malodorous substances, the third filtering unit 20′″ act both physically and chemically upon the exhaust gases, by oxidising these mixtures.
To the object, the system may comprise one or more containers 230 of an oxidising product, such as ozone, to be added to the water. In this way, from the third high pressure nozzles 24′″ atomized water is released supplied with the oxidising product.
Advantageously, the third filtering unit 20′″ may be configured so as the third high pressure nozzles 24′″ spray atomized water into drops having an average diameter of 5 μm to 30 μm and at a working pressure of 200 bar to 300 bar. Suitably, furthermore, the exhaust gases to be filtered and the atomized water flowing out from the third high pressure nozzles 24′″ may be in co-current and tangentially relative.
Preferably, each one of the filtering units 20′, 20″, 20′″ may include a respective support structure 205′, 205″, 205′″, for example a steel structure, and a respective high pressure pump 22′, 22″, 22′″ connected to a respective collector 23′, 23″, 23′″.
In a preferred but not exclusive embodiment of the invention, the at least one filtering unit 20′, 20″, 20′″ may be placed inside the ventilation duct TV of the tunnel T.
For example, the at least one filtering unit 20′, 20″, 20′″ may be placed at the entry of the ventilation duct TV.
On the other hand, in another embodiment, the at least one filtering unit 20′, 20″, 20′″ may be spaced apart from the tunnel T, externally thereto.
This embodiment is particularly useful in case the conformation of the tunnel T and the surrounding landscape is such to not allow the manufacturing of long ventilation ducts, such as in the case of towns tunnels T or tunnels placed nearby urban centres.
In this case, the filtering units 20′, 20″, 20′″ act as real filtering modules, that may be placed where the space surrounding the tunnel T allows it. For example, the filtering units or modules 20′, 20″, 20′″ may be assembled on support elements, for example steel towers, possibly in an above-ground position with respect to the tunnel T.
Then, depending on the space available, the filtering modules 20′, 20″, 20′″ may be assembled side by side or overlapped.
In this embodiment, the at least one filtering unit 20′, 20″, 20′″ may be fluidly connected to the tunnel T and/or to the ventilation duct TV thereof, possibly through one or more flexible pipes 240.
In case of more filtering modules 20′, 20″, 20′″, the same may be connected to each other through respective flexible pipets 245′, 245″.
Suitably, each filtering module 20′, 20″, 20′″ may be accessible by an operator for repair or maintenance, for example through a port or an appropriate passage.
In this case, the support structure 205′, 205″, 205′″ of each filtering module 20′, 20″, 20′″ may internally include the high pressure nozzles 24′, 24″, 24′″.
Furthermore, in a preferred but not exclusive embodiment, one or more operative modules 250 may be provided outside the tunnel T which contain the high pressure pumps 22′, 22″, 22′″. As particularly shown in
It is understood that the above mentioned embodiment with the nozzles 24 susceptible to prevent the entry into the tunnel T of dirt and foreign bodies may further be manufactured with the filtering modules 20′, 20″, 20′″.
In other words, one or more filtering modules 20′, 20″, 20′″ may be provided susceptible to prevent the entry therein of dirt and foreign bodies. Certainly, in this case, the fan means V have to be configured to force the inflow of fresh air into the tunnel T.
From the above description, it is clear that the system 1 achieves the intended objects.
In particular, the system 1 allows the treatment of exhaust gases flowing out from and/or flowing in a tunnel T with minimum environmental impact, since it exclusively uses atomized water.
Furthermore, the system 1 allows the treatment of exhaust gases flowing out from and/or flowing in a tunnel T with minimum inlet losses, since there is almost no physical barrier to the forwarding of the exhaust gases.
Moreover, the system 1 is simple to manufacture and manage, it has a relatively high time duration and it requires a minimum maintenance.
The system 1 is susceptible of numerous modifications and variations. All the details may be replaced with other technically equivalent elements, and the materials may be different according to requirements, without departing from the scope of the invention defined by the appended claims. cm 1. A system for filtering fresh air flowing in a tunnel (T) overlying one roadway (R) and/or for filtering exhaust gases flowing out therefrom (T), comprising:
| Number | Date | Country | Kind |
|---|---|---|---|
| VI2014A000164 | Jun 2014 | IT | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IB2015/054789 | 6/25/2015 | WO | 00 |
