The present invention relates to a method and a system or facility for creating circulation in a tunnel. The purpose of the circulation in the tunnel is to create ventilation and/or air purification in the tunnel during normal operation or under abnormal operating conditions, such as e.g. fire in the tunnel.

In today's mechanical ventilation of tunnels, dozens of fans, which can be mounted in the roof of the tunnel, are being used with the intention of creating a circulation in the tunnel. This technology works poorly and is very energy intensive. When a trailer or a large truck / lorry is for example coming against the direction of circulation, this trailer or large truck / lorry will stop the circulation and will contribute to the initiation of turbulent flows.

One purpose of the present invention is to propose a better solution compared to the known technique.

Another purpose of the invention is to provide a method and a system / facility for creating circulation / ventilation in a tunnel, which is more cost-saving (during development / outbuilding, in operation and/or during maintenance) than the known conventional ventilation systems and methods.

Yet another purpose of the invention is to provide a method and a system / facility for creating circulation / ventilation in a tunnel by means of a low, but sufficient, overpressure.

The invention relates to a method and a system / facility for creating / formation of circulation in a tunnel, the main features of the invention being indicated in the independent patent claims. Further features of the invention appear from the dependent claims.

One or more of the advantages of the present invention may be the following:

1) Rapid evacuation of smoke and exhaust and/or toxic gases from the tunnel.

2) Fast / rapid evacuation of high temperatures from a fire source in the tunnel.

3) No technical installations inside the tunnel that could be damaged by fire or explosions.

4) No technical installations inside the tunnel that could be damaged by collision from cars or other technical vehicles in neither the roof nor the walls.

5) No fan installations that can be damaged by fire or explosions, as all these fan installations are placed outside the tunnel in the open air.

6) Less humidity in the tunnel, and dew on the car window will disappear or be reduced.

7) In the event of a fire in the tunnel, there will not be a huge temperature rise at the scene of the fire therein.

This invention is completely superior to all other systems we have today in case of a fire in e.g. electric vehicles (battery-driven vehicles or other vehicles that use electricity from batteries), where, in addition to smoke, there are many highly toxic gases coming out, which have proved to be almost impossible to extinguish. Due to the rapid evacuation of smoke and exhaust and/or toxic gases, there will always be clean air on one side of the fire object. According to the invention, pressure cleaning of and/or pressure circulation in the tunnel is to be used. This pressure circulation can be left on all the time. It may be sufficient to create overpressure in the tunnel by using a relatively low (over)pressure, such as e.g. pressure which is higher than approximately 1 atm (atmosphere) and lower than approximately 2 atm, and preferably between approximately 1 atm and approximately 1,5 atm, with supply of clean and/or dry air. Here we are talking about an overpressure from about a couple or a few millibars (mbar / mb) above the normal air pressure for the tunnel area. Here we are talking about excess pressure / overpressure of a few millibars in relation to the surrounding atmospheric pressure. The pressure is distributed equally in all directions immediately, so that the tunnel will be close to 100% free of emission / exhaust gases and/or particulate matter or suspension dust from the vehicles and/or unwanted moisture. This (over)pressure can be regulated, so that in case of heavy loads (i.e. heavy traffic, fire) the pressure will be increased, and the supply of clean and/or dry air will consequently be increased, so that the air quality in the tunnel will be able to be maintained in a predetermined area, such as e.g. within certain limits permitted by the authorities. The air pressure or excess pressure / overpressure can be mainly brought into the center of the tunnel by means of at least one (ventilation) canal comprising at least one opening, which at least one canal can be arranged in or on the roof, and/or in or on the tunnel wall(s), and/or under the driving / road lane and/or the roadside / road edge or the ground. At least one fan device suitable for formation of overpressure in the tunnel may be placed on / at at least one side / opening of the tunnel, i.e. out in the open air, and may be connected to at least one canal or duct. The at least one fan can in addition be placed in a fan housing connected to said at least one canal / duct. It should be noted that the overpressure opening(s) of the at least one canal may in some cases (e.g. depending on terrain, tunnel design and/or tunnel position) be deployed not necessarily mainly in the middle of the tunnel, but at another place in the tunnel (e.g. from about 1/4 to about 3/4 of the tunnel length taken with respect to either exit or opening of the tunnel).

In the case of air purification in the tunnel under normal conditions, there will be quickly evacuated at least one of: emission / exhaust gases from vehicles, particulate matter or dust from vehicles, toxic gas(es) and/or unwanted moisture in the air in the tunnel. The advantage of pressure cleaning of the tunnel is that it is constantly under a relatively low overpressure with supply of large amounts of clean / fresh air. In this case, the pressure is not the essential thing, but the amount of air supplied into the tunnel. The amount of air can be regulated at all times, so that under heavy loads (i.e. heavy traffic) the amount of supplied air can be increased, so that sufficiently good air quality in the tunnel can be maintained. The amount of air is fed into approximately the middle of the tunnel by means of ducts / canals arranged in the ceiling and/or in and/or on the walls, but preferably, if possible, under the roadway and/or ground, and by using fans that can be mounted in fan housings. The fans with the fan housings may have been placed outside in the open air, and can have a capacity of up to approximately 2 to approximately 5 million cubic meters of air in hour, and in one embodiment between 3 and 4 million cubic meters of air per hour.

As previously stated, there will be excess pressure / overpressure in the tunnel at all times, so that at start-up of a fire (i.e. under abnormal or undesirable c2jnditions) the pressure and amount of supplied clean air will be automatically increased up to the maximum. In this way, the evacuation of smoke and/or gases from the fire scene will start almost immediately. It should only be mentioned that the quantity / amount of supplied air may be more important than the actual size of the excess pressure / overpressure.

In the event of a fire, the temperature in the tunnel is increased, so that turbo effect and/or chimney effect will be able to occur, which means that more air (including smoke) is taken out of the tunnel than fresh air that is led / entered therein. Thus, large amounts of smoke at the fire scene will not have time to build up, as these are evacuated almost immediately. A fire needs air in order to burn, i.e. it takes all the air (the oxygen) in the tunnel and will theoretically smolder and die out by itself when the air (the oxygen) is gone, with the corollary or consequence that completely black smoke will come or occur from this poor combustion. Inside the tunnel there may also be many people, and with the current systems the threats to them may not only be dying from smoke poisoning and/or heat, but also from lack of fresh air (i.e. oxygen). In the case of an overpressure tunnel, clean and cold air will be added all the time from the outside (which air is colder than that in the tunnel), with the advantage that air is added with approximately 21% (20,946%) oxygen, which leads to that light smoke will be coming from pure combustion, and that not only smoke, but also combustion heat, will be evacuated, so that people can stay on the non-smoking / smoke-free side. It should be mentioned that oxygen is necessary for (smokeless) burning.

At the scene of the fire, there will be approximately 99,900-99,999% of the cases free of smoke on one side, so that in the event of a fire, the fire service will be able to drive freely to the scene of the fire from the non-smoking / smoke-free side, and will have an approximately normal temperature and will be able to stand in a cold and/or smoke-free environment in order to extinguish the fire. From which side the fire service will be able to drive in is depending on where the fire is in relation to the pressure chamber(s) in the tunnel. The approximately 0,100-0,001% is if the fire should have started right under the open air or overpressure openings of the at least one duct / canal in the tunnel, i.e. at the pressure chamber, but the smoke will then be evacuated both ways. A fire can never damage the overpressure system, because all the (important) technical installations and/or facilities are arranged or placed outside the tunnel, inside the tunnel there are only canals of e.g. steel, or under the roadway and/or the ground where the canal essentially consists of pipes which can be made of e.g. concrete. In another design, reinforced composite pipes may be used to form the canal. Steel canals in the ceiling will only be used in tunnels where it is most appropriate.

It should further be noted that the system or facility according to the invention is almost maintenance-free (especially on the inside of the tunnel). Any maintenance and/or repair work may be necessary to a large extent on the outside of the tunnel in connection with the fan or overpressure formation device(s).

Furthermore, dew problems in the tunnel will be eliminated due to the supply of fresh and/or dry air from the outside.

In the tunnels, one or more evacuation rooms can be built, which can also be connected to said at least one canal / duct for adding excess pressure / ovf3 pressure from the fresh air canal(s). This/these will constantly receive a supply of clean and/or cold air from the outside. At a given temperature rise above a certain temperature limit or level the door to each evacuation room can be unlocked or opened using a control device which shall be configured to control the entire ventilation system.

At a given temperature rise above a certain temperature limit or level the tunnel can be closed automatically and immediately by using booms, so that we get minimal vehicles in the tunnel. In addition and/or alternatively, traffic light regulation can be used to stop the vehicles at a red light. The booms can e.g. be placed with a predetermined distance of, but not limited to, e.g. about minimum 50 meters from the tunnel opening, so that there is enough space for vehicles / cars that are being evacuated from the tunnel.

Alternatively, the booms can be placed immediately at the tunnel opening and can be configured to open automatically for vehicles / cars evacuating from the tunnel. Numerous temperature sensors can be installed or mounted along the entire tunnel / tunnel stretch. Further smoke, gas and/or humidity sensors can be fitted or mounted along parts of or all of the tunnel. If any of these sensors will be damaged by fire this will not have any impact on the fans as these must be switched off manually, e.g. in a control room outside the tunnel. All equipment, necessary for control or management of all sensors within the tunnel and/or of the fans outside the tunnel, may be deployed in the control room. Video surveillance, using cameras deployed on desired places, can be provided in the tunnel and possibly at the tunnel's exits. All necessary equipment for video surveillance, including at least one monitor and/or recorder, can also be deployed in the control room. All management and operation of components and equipment may be automated and computer-based and/or, if necessary or in addition, manually by an operator. The fire brigade, police and/or ambulances may have remote controls in their vehicles for opening the booms at the tunnel openings.

Figure 1 shows a possible embodiment of the tunnel facility or system according to the invention.

Figure 2 shows another embodiment of the tunnel facility or system according to the invention.

Figure 3 shows a third embodiment of the tunnel facility or system according to the invention, seen from above.

Figure 4 shows a cross-section of the tunnel of the tunnel facility or system according to a first alternative design of the third embodiment of the invention, namely with the canals arranged directly under the roadway.

Figure 5 shows a cross-section of the tunnel of the tunnel facility or system according to a second alternative design of the third embodiment of the invention, namely with the canals arranged directly under the roadway and the tunnel.

Figure 6 shows an end of the tunnel of the tunnel facility or system according to the first alternative design of the third embodiment of the invention.

Figure 7 shows a cross-section of a part of the tunnel facility or system according to the first alternative design of the third embodiment of the invention, namely a pressure chamber seen from the side.

Figure 8 illustrates another embodiment of the system or facility according to the invention with an overpressure supply room or chamber shown in detail Figure 9 illustrates yet another embodiment of the system or facility according to the invention with an overpressure supply room or chamber shown in detail.

As regards all the figures, it should be noted that the use of ' in the reference numerals means that a respective component is on a so-called left or west or north side of a tunnel 1 according to the invention, while the use of " in the reference numerals means that another respective component is on a so-called right or east or south side of the tunnel 1. Of course, the tunnel sides should not be limited to east and west or south and north, because any tunnel can have a different orientation. This is only indicated to exemplify the invention and to simplify the understanding of the invention. On figure 1 the mentioned tunnel 1 is illustrated where a first embodiment of the system according to the invention is deployed or mounted. This embodiment constitutes a ventilation system comprising at least one device 2 for the formation / creation of a specific and/or controlled overpressure in the tunnel 1. The overpressure device 2 is arranged on a suitable location near or close to at least one first side or opening 22 of the two tunnel openings 22 / 22', 22". The overpressure device 2 can comprise an open-air (fresh air) fan housing which is suitable for e.g. protection from the environment and/or weather conditions of all the components arranged into the overpressure creation device 2. The overpressure device 2 can comprise a suitable fan device 21 which is adapted to create the determined and/or controlled overpressure in the tunnel 1. The overpressure device 2 can e.g. have an overpressure supply capacity of but not limited only to approximately 1-2 million m ³ air volume per hour. Furthermore, the invention is not limited to suitable fan devices only, and it shall be understood that other equipment being intended for formation of overpressure and which would be suitable for this application, will also be able to be used. The excess pressure / overpressure can be controlled and/or managed and/or regulated with the help or use of a control device. The control device can be arranged in the at least one overpressure creation device 2. The control device can regulate the excess pressure / overpressure by e.g. controlling and/or regulating the speed of the fan in the fan device 21. The control device can e.g. regulate the excess pressure / overpressure, so that by heavy loads (i.e. heavy traffic) or in the event of an accident (e.g. fire) the pressure will be increased. The control device may comprise a processor or a computer for controlling or regulating all processes in the system and a memory for storing a program of computer executable instructions, etc. Even If there is no traffic, the overpressure supply can be switched off completely or be significantly reduced in order to save energy. The overpressure device 2 is connected to at least one canal 3 which is attached or arranged in or on the ceiling 11 of the tunnel 1. It is also possible to have said at least one canal 3 attached or arranged in or on at least one of the tunnel's 1 walls 12, 13, and/or under the roadway and/or ground 14. The at least one canal 3 can have different profiles / cross-sections, such as e.g. round, oval, square, etc. The canal profile and its cross-section shape may depend on available space in the tunnel 1. It should be noted that the canal profile will not take up more space than a current fan device with a fan housing, if it is placed in the roof / ceiling 11 inside the tunnel 1. The hollow canal can be made of metal, such as e.g. steel, or of other suitable non-combustible material. Furthermore, metal pipes or steel pipes can be used to place the canal(s) 3 in the system / facility. The end of the canal 3, which is not connected to the overpressure creation device 2, is pr5jvided with a device 4 for supplying the excess pressure / overpressure. The overpressure supply device 4 may comprise at least one (discharge) opening 41 for supply of the tunnel 1 with excess pressure / overpressure. The overpressure supply device 4 can be located near the tunnel's 1 center. The opening(s) 41 can be disposed or arranged / oriented to ensure discharge or supply of overpressure across the driving directions in the tunnel 1 (i.e. approximately 90 degrees to the direction of travel), thereby to build up excess pressure / overpressure in the tunnel 1 and not to blow air in the driving directions.

The system can also comprise at least one temperature, smoke, gas and/or humidity sensor (not shown) which can be mounted along or in parts of or all of the tunnel's 1 stretch or length. Said at least one sensor can read and/or monitor the environment in parts of or all of the tunnel's 1 stretch or length. The sensor reading and/or monitoring can be done continuously or periodically. Sensor reading data can be taken to the control device. The control device can, upon detection of unwanted deviation, send a first signal to the at least one overpressure creation device 2 in order to increase or decrease the excess pressure / overpressure in the tunnel 1, and/or another signal to a boom device arranged on each side of the tunnel 1 for closing the tunnel 1, so that all traffic entering the tunnel is stopped immediately. The boom device can be arranged at / with a predetermined distance from the opening 22 of the tunnel 1.

The system can further comprise at least one shelter or rescue room 5 that by means of a branch or canal branch 31 is connected to the at least one (fresh air) canal 3, so that this or these room(s) will be left in / under overpressure of clean fresh air from the outside of the tunnel 1. Canal branch(es) 31 can have the same or different shape and/or dimension and/or material use as in relation to the canal(s) 3. In or by the end of the branch 31, which is directed towards said room 5, at least one heating element (not shown) can be mounted or arranged, so that, at low external temperatures (such as below approximately 10-15 Celsius degrees, i.e. from approximately 15-10 Celsius degrees to about 0 Celsius degrees) or at minus degrees, it will be possible to maintain a normal indoor temperature inside said rescue room 5. Said rescue or escape room 5 can be put into the mountain. Each room 5 or a group of rooms 5 can also comprise an extra and independent ventilation device (not shown). At a given temperature increase in the tunnel 1 above a certain temperature limit or level the door to each evacuation room can be unlocked or opened using the control device configured to control the entire ventilation system. Furthermore, the control device can be configured to switch on the supply of fresh air to each evacuation room 5 at the given temperature rise above the specified temperature limit or when the door to room 5 is opened. Possibly only evacuation rooms on the smoke side can be opened and supply of fresh air thereto can be started, because evacuation on the nonsmoking / smoke-free side will be possible.

From the other outer side or opening 22 of the two tunnel openings 22', 22" the same, as the above- mentioned arrangement, can be mounted or arranged. In this case the overpressure being supplied by each overpressure creation device 2 at each tunnel opening 22 can be the same or different. The overpressure supply devices 4 from each of the two tunnel openings 22 / 22', 22" can be arranged near / in (immediate) proximity to each other, but separated from each other. In the event that the overpressure supply devices 4 shall be separated from each other, these can be arranged with a determined advantageous longitudinal distance from each other. The determined longitudinal distance between the overpressure supply devices 4 can be e.g., but is not limited only to, approximately 0,03 m; about 0,05 m; about 0,1 m; about 0,5 m; about 1 m; about 1,5 m; about 2 m; etc. According to two further embodiments the overpressure supply devices 4 can be separated from each other only by the use of a (partition or intermediate) wall, or these overpressure supply devices 4 can be arranged wall to wall without any distance therebetween. Alternatively, the overpressure supply devices 4 for the facilities for the two tunnel openings 22 can have been joined together, so that only one overpressure supply device 4 (as shown in fig. 2) is formed. It should be noted that it is important to add the overpressure at a specific location (at a specific longitudinal section or stretch) and not at different places (sections) in the cases where it was supposed to use two or more of the above-mentioned arrangements for overpressure circulation.

It should be noted that the overpressure supply device(s) 4 to the at least one canal 3 can in some cases (e.g. depending on terrain, tunnel design and/or tunnel position, etc.) be deployed not necessarily mainly in the middle of the tunnel 1, but at another appropriate / suitable place in the tunnel 1 (e.g. from about 1/4 to about 3/4 of the tunnel length taken with respect to either exit or opening 22, 22', 22" of the tunnel 1). As said the overpressure supply device(s) 4 can be located or arranged e.g. by an emergency pocket (not shown). Furthermore, the opening(s) 41 can be arranged to deliver overpressure towards the emergency pocket (and not towards the road or roadway).

The longitudinal length along which the overpressure supply device(s) 4 is(are) arranged / deployed therein or covering the length of the tunnel can be from about 0,1 m and up to about 40 m, especially between approximately 0,5 and 30 m, and preferably between e.g. about 1 and 25 m or between e.g. about 1 and 20 m, and especially between approximately 2 and 10 m. This effective length and/or the location length for the overpressure supply device(s) 4 should not be limited only to the above-stated examples or limits.

After each overpressure creation device 2 in the direction of the overpressure supply device(s) 4, a filter / mesh / grating device can be arranged to prevent the introduction of unwanted particles and/or other objects into the canal(s) 3, which may be of such a size that it could possibly damage the canal(s) 3 and/or the canal branch(es) 31 and/or overpressure supply device(s) 4, and/or could block one or more of the openings 41 of the overpressure supply device(s) 4.

Figures 3-7 show other embodiments of the invention, where the at least one canal 3 can be arranged under the tunnel's 1 roadway 10. Furthermore, said at least one device 4 for supplying the overpressure (i.e. the at least one overpressure supply device) can constitute an overpressure supply room / overpressure chamber 40 which can be disposed or placed on at least one side of the wall 12, 13 of the tunnel 1. The overpressure supply room 4, 40 can have a grid or mesh 45 with openings 41, so that the supply of excess pressure / overpressure is provided across the roadway 10 and the driving directions in the tunnel 1, i.e. approximately 90 degrees in the direction(s) of travel. The system or facility according to the invention works most optimally when the overpressure supply room(s) or chamber(s) 4, 40 is(are) arranged at one place being from about 1/4 of the length of the tunnel 1 to about 3/4 of the length of the tunnel 1 taken with respect to either end, e.g. exit or entrance or opening 22, 22', 22" of the tunnel 1.

When two overpressure creation devices 2 with two fan devices 21 are used, i.e. with one on each side of each end 22 of a tunnel 1 with e.g. two tunnel openings 22, 22', 22", the two overpressure supply rooms or chambers 4, 40 can be arranged opposite and/or facing each other, i.e. one in a side wall 12 of the tunnel 1 and the other in the other side wall 13 of the tunnel 1, so that the overpressure is supplied across the roadway (i.e. approximately 90 degrees to the carriage- or roadway) and from either side of the tunnel's 1 walls 12, 13 directly above each other.

Figure 8 illustrates another embodiment of the system or facility according to the invention with an overpressure supply room or chamber 4, 40 shown in detail. Here the at least one canal / duct 3 is led to the at least one overpressure supply room or chamber 4, 40 from the top of the area 50, e.g. a mountain, an earth formation, a rock or a mass of water, through which the tunnel 1 is running.

Figure 9 illustrates yet another embodiment of the system or facility according to the invention with an overpressure supply room or chamber 4, 40 shown in detail. Here the at least one canal / duct 3 is led to the at least one overpressure supply room or chamber 4, 40 from a side of the area 50, e.g. a mountain, an earth formation, a rock or a mass of water, through which the tunnel 1 is running.

In the overpressure supply room or chamber 4, 40, shown on figures 8 and 9, there is means 47 configured for killing the mechanical air flow coming from the canal / duct 3. Said mechanical air flow killing means 47 can be arranged in front of or in the proximity of the canal opening, which canal opening is, on figures 8 and 9, arranged on one wall of the overpressure supply room or chamber 4, 40. Alternatively, said means 47 for killing the mechanical flow coming from the canal / duct 3 can be arranged in front of or in the proximity of the grid 45, or at any other suitable place, so that the mechanical air flow coming from the canal / duct 3 will be stopped and killed by said means 47 and will not go directly through the grid 45. Said means 47 for killing the mechanical flow can be a wall arranged in the proximity of the entire area or even more of the entire area of: i) the canal opening connected to the overpressure supply room or chamber 4, 40 (figures 8 and 9), or ii) the grid 45 of the overpressure supply room or chamber 4, 40 (not shown), respectively. Arrows A are showing the mechanical air flow coming through the canal 3 from the fan device 21. which fan device 21 is connected to the other opening of the canal 3. And arrows B are showing the immediate distribution of the overpressure within the tunnel 1, without any mechanical blowing of air. Said means or wall 47 for killing mechanical air can be arranged in one plane (e.g. having I form / shape) or in even more planes (e.g. having respectively V or fl or C shape / form).

In alternative embodiments (not shown) the canal opening connected to the overpressure supply room or chamber 4, 40 can be arranged on the ceiling of the overpressure supply room or chamber 4, 40 in such a manner, so that the mechanical air flow A coming from the canal 3 will be directed towards and killed in the wall of the overpressure supply room or chamber 4, 40 that is opposite to the grid 45, or the mechanical air flow A coming from the canal 3 will be directed towards and killed in the floor of overpressure supply room or chamber 4, 40, so that in these cases the means 47 for killing the mechanical flow will not be needed.

The size and volume of the overpressure supply room or chamber 4, 40 can be calculated based on the tunnel's 1 length and/or density. Composite or cement pipes with e.g. a diameter of approximately 80 cm can be used. The pipes 3 can be reinforced. However, other diameter sizes can be used since the diameter depends on the length of the pipe and/or the amount of air that is desired to be supplied into the tunnel 1. It should first be calculated how much air is desired to be supplied into the tunnel 1, and then the diameter of the pipe 3 can be calculated. The tunnel 1 may be suitable for cars, trucks and/or trains and/or other vehicles or vessels.

Furthermore, the system and method according to the invention can be used in tunnel systems with more than just two tunnel openings 22 / 22', 22".

It is obvious that other embodiments or variants of the invention that fall within the scope of the patent claims, shall also form a part of the invention.