The subject of the invention is a fire extinguishing system designed to extinguish fires in road tunnels or tunnels, which can extinguish fires quickly and efficiently without requiring the direct (physical) presence of people.

As such, the invention solves the problem how to extinguish fires in road tunnels. It solves the technical issue of how to design a fire extinguishing system in a tunnel in such a manner that it could immediately begin extinguishing a fire either partially or wholly automatically, without people needing to intervene. Fires are very common in tunnels around the world, and several factors can cause them; two such examples are vehicle breakdowns and traffic accidents.

Research in the field of fire safety has shown that a fire on a vehicle quickly spreads in the initial 5-10 minutes. When a vehicle catches fire, the systems currently used in modern tunnels automatically report the event, but the fire can also be reported by eyewitnesses. Afterwards, the control centre sends an intervention team, informing them of the location of the fire. However, it has been estimated that a full hour can pass from the moment the rescue team receives a call to the time they reach the fire. Such a long period can also increase danger for the team. The automatic system could thus help save many lives and prevent potentially severe damage to the infrastructure caused by a fire, which would call for renovation and long-term closure of the tunnel.

Currently, several solutions for tackling the issue of fires in tunnels exist, but these are only passive, which means that the fire is not extinguished automatically. We must also acknowledge the hydrant networks and fire extinguishers that are used for extinguishing fires with water, but these are only used by those individuals that feel sufficiently educated and confident in their use. Detection systems (systems with sensors and cameras, manual, point and line systems) that are installed in front of the tunnel, on visible spots in the tunnel, on emergency phone boxes at entrances to transverse connecting tunnels near twin-tube tunnels, and so on, start automatically or by someone pressing a button that sends a fire alarm and the exact location of the fire to an operator at the relevant control centre. Tunnels also have ventilation systems that direct the fire flow and supply fresh air to people nearby in the tunnel. Call panels and evacuation routes with transverse tunnels are used for informing and evacuating people from the affected location; as such, however, they have no effect on the fire itself. Some direct systems or products for extinguishing tunnel fires do exist, but very few. The RoboGat system, an invention with the patent application code EP 1169092, is still not fully automatic and its function depends on the fire extinguishing pipe system. The system must be connected to a nozzle every 20-30 metres for access to water. Because of this, it is only suitable for short distance applications, such as garages.

The HI-FOG system, which is produced by the German company Tyco and used for extinguishing fires with water fog, is similar. It is a sprinkler-type system that uses pure water to achieve this, and requires many sprinklers and large amounts of water, so that the water can disperse into droplets when a fire needs to be extinguished. The problem with this system is the amount of water it requires - it would be difficult to find enough space for a large pool near a road tunnel. Indeed, this is the exact reason why this system is not installed in road tunnels. Apart from this, a water fog system also requires high-pressure pumps to function. These pumps distribute the water fog to nozzles, which must be installed in the related structure. The same problem with space arises - where could one install them in a tunnel?

Unlike the existing solutions, our system, the focus of this patent application, requires no water pool or piping, which is why it is the most appropriate system for use in tunnels.

The invention will be described in greater detail below, including an example of use and enclosed drawings presenting the following:

Fig. 1: Firefighting vehicle - front view

Fig- 2: Firefighting vehicle - lateral view

Fig. 3: Firefighting vehicle - rear view

Fig. 4: Firefighting vehicle - plan view

Fig. 5: Firefighting vehicle - isometric projection

This fire extinguishing system for tunnels consists of a firefighting vehicle A or of more such engines, a ceiling frame B on which the vehicles A move, and a filling station on which the vehicle A is attached and always prepared to start. The vehicle stands in a filling station located in the service tunnel or a lay-by. The invented system also includes software for controlling and operating the firefighting vehicle A. The software is installed in the control centre, which does not need to be in the tunnel. Operators on duty work with this software in the control centre and control the other tunnel systems as well. The firefighting vehicle A consists of the following essential parts: a supporting frame A2, a tank for the extinguishing agent A3, a nitrogen cylinder A4, a spray cannon A5, guides with wheels A6, a drive wheel A7, a fork or frame on which the drive wheel A8 is attached, a spring that ensures contact force to the drive wheel A9, a colour camera (RGB camera) A10, infrared camera A11 , colour camera for the back end A12, a chain drive for the transmission of energy from the motor to the drive wheel A13, a battery A14, a control cabinet A15 and a motor A16.

In case of fire, the operator at the centre activates the vehicle A closest to the burning sector - this is an example of semi-automatic use of the system. The vehicle can also operate autonomously, i.e. fully automatically, by driving to the location of fire with the help of thermal imaging. The infrared camera A11 detects the largest thermal load and sends the information to the computer programme, which transmits the focal point coordinates to the control block of the spray cannon A5, directs it towards the focal point and extinguishes the fire. The guides A6 on which the vehicle A moves are mounted on the vehicle A and move onto the supporting frame B, which is fixed to the tunnel ceiling. This gives the vehicle the closest possible access in the tunnel at all times, as the system is not hindered by road traffic in the tunnel - this is an issue, as the drivers may either move their vehicles to an inappropriate location, or the damaged vehicles involved in the accident may not be able to be driven aside to make room for the intervention team. This is possible due to the low profile of the frame A2 of the firefighting vehicle A. It enables movement above the signalling equipment and other infrastructure. The activation or the procedure to move the firefighting vehicle A from the service tunnel or lay-by via the guide A6 onto the main ceiling frame B lasts about 10 seconds. When the vehicle A is on the ceiling frame B, it can move in both directions.

The operator at the control centre takes over the commands and drives the vehicle A to the location of the fire. Its speed is about 22m/s, so it can reach a location 500 metres away in 22 seconds. If we acknowledge the acceleration and braking time, the total time needed to reach the location is about 30 seconds. The vehicle A uses a DC motor A16, which is supplied by the battery A14 on board. The motor A16 has enough power to move the entire weight of the vehicle A together with the extinguishing agent in the tank A3. Since the vehicle has its battery A14 on board, its movement is not hindered by supply lines. This also prevents the danger of electric shocks to people standing in the vicinity. The choice of this particular battery A14 ensures that the vehicle A will function for 4-5 hours. This enables the vehicle to function without the charging station during longer blackouts. The operator guides the vehicle A with the help of one camera A10 at the front and the other A12 at the back end of the vehicle A. If the tunnel is filled with smoke, guiding can be done via the infrared camera A11 , which shows a clear image of the fire. The vehicle A is instantly prepared for extinguishing the fire once it reaches the location. The operator activates the solenoid valve on the nitrogen cylinder A4, a component for extinguishing fire. Nitrogen is used as a propellant, which pushes the extinguishing agent from the tank that contains it A3 (the agent can be, for instance, BIOVERSAL, a heavy foam, or some other appropriate agent used for extinguishing burning vehicles). This enables the pressure in the tank with the extingusihing agent A3 to reach an appropriate level for extinguishing, e.g. 16 bar (230 psi) in 5 seconds. The extinguishing is carried out through the spray cannon A5, which can be rotated by 300° on both axes via a control lever from the control centre. The range of the cannon A5 is wide enough to cover the entire width of the largest existing tunnels. The range is controlled through a pressure regulator in the adjustable nozzle at the end of the spray cannon A5. The tank A3 is large enough for extinguishing large fires, and it can hold a reasonable amount of the extinguishing agent. After the intervention, the operator drives the vehicle A back into the service tunnel or lay-by, where it automatically connects to the electric filling station. While it is serviced at the filling station, the tank A3 is refilled with the extinguishing agent, the cylinder A4 is refilled with nitrogen and a full vehicle A check is carried out. In longer tunnels, it is possible to employ vehicles A intended for extinguishing other parts of the tunnel. The optimal number of vehicles A in a tunnel is one vehicle A per km. Example: we install two vehicles A in a 2km tunnel. Each covers 1km, which is 500m on each side. This way we ensure a rapid response and prevention of additional damage during a tunnel fire. If the customer demands or needs more or less vehicles A per kilometre, the number of vehicles installed in the tunnels can be adapted.

The main characteristics or advantages of this system are the following:

- Low profile A2, which enables the vehicle to move through the entire tunnel.

- Fast activation, approx. 30s pass from fire detection to the time the extinguishing is initiated.

- Battery drive A14 enables functioning without charging for several hours.

- Infrared cameras A11 in case of poor visibility.

- Amount of extinguishing agent is large enough for an extensive fire.

- Range of spray cannon A5 is long enough to cover the entire width of the largest existing tunnels.

- Precision of extinguishing, as it can be performed from various angles. - Physical presence of intervention personnel is not necessary (and thus there is a smaller risk of injury and death).

- No additional installations needed.

- No large water tanks and pumps needed.

- Smaller risk of faults, greater efficiency and faster response.

Let us give a concrete example of the use of this system. A vehicle was stuck in a lane 2.8km from the entrance of the tunnel due to engine failure. An absent-minded truck driver noticed it too late and hit the back end of the stationary vehicle. Due to inadequate safety distance another truck collided with the vehicle and caught fire immediately. The tunnel smoke detectors reported the event to the control centre. The operator turned on the control camera of the sector to check the real situation in the tunnel. He contacted the rescue team and chose vehicle A no. 3, which covers the area between the second and third kilometre of the tunnel, to intervene. He chose vehicle no. 3 on the control panel and activated manual control of the vehicle A. The vehicle reached the location of the event in 25 seconds, ready for immediate extinguishing. Due to poor visibility caused by the smoke, the operator relied on thermal imaging to put out the fire (via camera A11) more easily. He used the data to direct the spray cannon A5 towards the focal point. He activated the nitrogen cylinder function A4. The cylinder is connected to a pressure-reducing valve and a hose, which are part of the cylinder A4, and the tank for the extinguishing agent A3. The compressed extinguishing agent began running through the spray cannon A5 to the location of the fire. The fire was put out in 30 seconds. After the intervention, the operator monitored the area via thermal imaging (camera A11) until the area could be controlled with a video surveillance system. The monitoring from a height gave him greater visibility, and it was thus easier to direct the intervention team towards the injured passengers. When the situation was under control, he returned the vehicle A to its starting point. He called the maintenance personnel to inspect the vehicle A and do any necessary maintenance work and prepare it for any future interventions.