SE545183C2

SE545183C2 - A fire extinguishing arrangement

Info

Publication number: SE545183C2
Application number: SE2151140A
Authority: SE
Inventors: David Westberg
Original assignee: Hexeye Solutions AB
Priority date: 2021-09-17
Filing date: 2021-09-17
Publication date: 2023-05-02
Also published as: SE2151140A1

Abstract

Afire extinguishing arrangement (1) is provided. The fire extinguishing arrangement comprises a water hose (10) configured to be connected to a water pump (15) and to receive water from the water pump, and a plurality of nozzles (20) arranged on at least a portion (11 ) of the water hose. The plurality of nozzles is configured to receive water from the water hose and to discharge said received water. The fire extinguishing arrangement further comprises a plurality of unmanned aerial vehicles, UAVs, (30) connected to the water hose and configured to lift at least the at least a portion of the water hose. The fire extinguishing arrangement further comprises power cabling (40) arranged within the water hose and electrically connected to the plurality of UAVs, wherein the plurality of UAVs is configured to receive electrical energy from an electrical energy source (45) via the power cabling, and wherein the power cabling is configured to be cooled by the water inside the water hose.

Description

A FIRE EXTINGUISHING ARRANGEMENT Technical field The present disclosure relates generally to the field of fire extinguishing, suppression and/or firefighting. More specifically, it relates to the field of wildfire suppression.

Background Wildfires, such as forest fires, are one of the most common forms of natural disasters, and wildfires may cause damage to property and human life. Therefore, there is an immediate need to suppress and/or extinguishing wildfires.

There are a number of available wildfire suppression technologies, such as wetting, smothering, or chemically quenching the fire, or by physically separating the burning from not burned fuel of the wildfire. Water may be applied directly to the burning fuel by fire personnel or an aircraft, such as an airplane or a helicopter.

Aerial firefighting, i.e. applying water onto a wildfire using an airplane or a helicopter requires access to a nearby water reservoir, from which the airplane or helicopter fills a tank, bucket, or container. Therefore, the firefighting capabilities of the aircraft are limited by the distance between a wildfire and the nearest suitable water reservoir. Further, the uptime of aircrafts and helicopters is limited due to needing to refuel. An additional problem with aerial firefighting is the lack of, and high cost of, aircrafts suitable for aerial firefighting. Thus, there is both a limit in the capabilities of current aerial firefighting in terms of efficiency of the aircrafts and in the availability of such aircrafts.

Additional challenges of today for aerial firefighting are the safety risks and the stress that firefighting personnel may be exposed to, which may limit the capacity and duration of the firefighting effort. Airplanes and helicopters are commonly delayed to firefighting efforts due to low visibility, caused by smokeor clouds, and in some cases due to downpour or strong winds. Another limitation of traditional aerial firefighting is that it primarily has to be performed in daylight, and therefore a big part of the potential time of fire suppression is lost.

Further, due to global warming, the number of wildfires, as well as the severity of wildfires, are steadily increasing. Therefore, the need for a more efficient, more available, and/or less expensive alternative of aerial firefighting will continue to increase.

Summary lt is therefore an object of the present invention to overcome at least some of the above-mentioned drawbacks, and to provide an improved alternative of firefighting.

According to a first aspect of the present disclosure, a fire extinguishing arrangement is provided.

The fire extinguishing arrangement comprises a water hose configured to be connected to a water pump and to receive water from the water pump. The fire extinguishing arrangement further comprises a plurality of nozzles arranged on at least a portion of the water hose. The plurality of nozzles is configured to receive water from the water hose and to discharge said received water. The fire extinguishing arrangement further comprises a plurality of unmanned aerial vehicles, UAVs, connected to the water hose and configured to lift at least the at least a portion of the water hose. The fire extinguishing arrangement further comprises power cabling arranged within the water hose and electrically connected to the plurality of UAVs. The plurality of UAVs is configured to receive electrical energy from an electrical energy source via the power cabling. The power cabling is configured to be cooled by the water inside the water hose.

According to a second aspect of the present disclosure, a system for fire extinguishing is provided.The system for fire extinguishing comprises a fire extinguishing arrangement according to the first aspect. The system further comprises a water pump connected to the water hose, configured to pump water into the water hose, and an electrical energy source configured to supply electrical energy to the power cable.

The present disclosure is focused on the use of UAVs for discharging water onto a fire in order to suppress the fire.

A fundamental limitation of any aerial vehicle is its ability to generate lifting power. Airplanes and helicopters are generally powered by petroleums, such as jet fuel, gasoline or diesel, which is very energy dense, in comparison to an electrical battery. A UAV may be too small for it to be efficient to use a combustion engine, while a battery may be too heavy if the UAV is configured for lifting and discharging water onto a fire. However, a UAV configured to receive electrical energy via power cabling, according to the present invention, is only weighed down by at least a portion of the power cabling, as compared to a combustion engine and fuel, or a battery. Thus, the present disclosure allows for a more efficient use of UAVs.

An additional benefit of the UAVs receiving electrical energy via power cabling is that it enables continuous operation of the arrangement. ln other words, the plurality of UAVs do not need to refuel or recharge. Further, since water may be continuously pumped by the water pump, the arrangement is not limited by the supply of water either, in comparison to known aerial firefighting, which needs to refill tanks, buckets, containers, or the like. Thus, a synergistic effect is achieved, which enables an increased continuity of operation of the arrangement.

A limitation of aerial firefighting, such as by using airplanes, is the need for proper take-off and landing sites, such as a runway. Further, refueling an aircraft may only be possible at certain locations. Therefore, airplanes, and helicopters, may be limited by having to start from a designated take- off/landing site, and may have to return to a site to refuel, which may decrease the time that the aircraft can be used for firefighting. The presentdisclosure solves this by providing an arrangement which may be transportable by a truck, a car, or a helicopter. Further, once the arrangement is set up, it may be operated continuously. Thus, the avai|abi|ity and the uptime is increased in comparison to aeria| firefighting using airplanes or helicopters.

The power cabling may comprise one or more power cables. A plurality of power cables may allow for more flexible power cabling than power cabling comprising a single power cable. However, power cabling comprising a single power cable may be more compact.

The amount of lifting power which the plurality of UAVs is able to generate is dependent on the amount of electrical power delivered to said plurality of UAVs via the power cabling. Therefore, it is of interest to maximize the electrical energy delivered via the power cabling. lncreasing the amount of electrical energy through the power cabling will consequently increase the amount of heat dissipating from the power cabling, due to resistive heating. lf the power cabling, or conductors of the power cabling, is dissipating too much heat insulation of the power cabling may be damaged, which may further damage components attached to the power cabling. However, by arranging the power cabling within the water hose, and the power cabling being configured to be cooled by the water inside the water hose, the power cabling may be configured to deliver more electrical energy to the plurality of UAVs without overheating. Thereby, the efficiency of the arrangement may be increased. During operation of the arrangement, there is a steady flow of water flowing through the water hose. Thus, the cooling of the power cabling may be kept at steady level, since a temperature of the water which is cooling a portion of the power cabling is substantially the same during operation of the arrangement.

The water pump may be configured to receive water from a water reservoir, such as a lake, a sea, a river, or a (local) water network. The water pump may further be configured to deliver water to the water hose with a pressure such that the water is delivered to the nozzles via the water hose when arranged atan height, which may be, for example, ten, twenty, fifty or one hundred meters. By the term "height", it is meant, for example, height above ground, height above the water pump, heigh above the ground on which the water pump is arranged, or altitude. Further, the water pump and the water hose may be configured to allow discharge of water at rates above 100 litres per minute, for example 200 litres per minute. For example, for water to be pumped to a height of 100m, a pressure of 10 bar is required. Further, the pressure produced by the water pump may have to compensate for pressure losses within the water hose. Furthermore, a high enough water pressure is desired at the nozzles. Thus, the water pump may be configured to produce a pressure, i.e. to pump water with a pressure, of at least 30 bar. The water pump may further be configured to produce a pressure of more than 100 bar.

The plurality of UAVs may be arranged along the portion of the water hose. Further, the plurality of UAVs may be arranged evenly distanced along the portion of the water hose. Another portion of the water hose may be connected between the water pump and the portion of the water hose. The other portion of the water hose may be understood as delivering the water towards the plurality of nozzles, which may be arranged above and aimed towards a fire. Therefore, the arrangement may be able to transport water from the water pump, via the other portion of the water hose, towards the portion of water hose, which comprises the nozzles and is lifted by the plurality of UAVs.

The water hose may be configured to allow some water to pass through the water hose, thereby keeping an outside of the water hose wet which may make the water hose more fire resistant.

The water hose, when receiving water from the water pump, may be configured to provide support and/or stability for the plurality of UAVs. The water hose, when receiving water from the water pump, may be pressurized such that a stiffness of the water hose is increased. An increased stiffness of the water hose may allow the water hose to provide support and/or stability of the plurality of UAVs. Thus, the controllability of the plurality of UAVs may beincreased. Additionally, the water hose, when receiving water, may be configured to prevent the plurality of UAVs from rotating due to torque created by rotors of the UAVs. Therefore, the plurality of UAVs may not need to compensate for the torque by, for example, angling a rotor of a UAV. Thus, the efficiency of the plurality of UAVs may be increased.

However, the water hose may be configured to hang below the plurality of UAVs, which may allow for the plurality of UAVs to be at greater distance from a fire than the water hose. Thus, the plurality of UAVs may be protected from the fire to a greater extent.

The electrical energy source may be, for example, a power grid, or a generator. lf a (wild-) fire is occurring in the vicinity of a power grid, the power cabling may thereby connected to the power grid. However, if the fire is not occurring in the vicinity of a power grid or of a suitable connection point to a power grid, the power cabling is able to be connected to a generator.

Therefore, the availability of the arrangement is increased.

The plurality of UAVs may be configured to be communicatively connected to a control unit which is configured for controlling the plurality of drones. The control unit may be configured to control each UAV of the plurality of UAVs individually. Alternatively, the control unit may be configured to control the plurality of UAVs collectively. The plurality of UAVs may be configured to be communicatively connected to the control unit via wire, or wirelessly.

The system may further comprise a control unit communicatively coupled to the plurality of UAVs. The control unit may be configured to control the plurality of UAVs. At least some UAVs of the plurality of UAVs may comprise one or more sensors. A sensor of the one or more sensors may be, for example, a temperature sensor, a camera, an IR-camera, or a radar. The control unit may be configured to control the plurality of UAVs based on meaSUfementS Of the One Ol' mOFe SGFISOFS.

At least some UAVs of the plurality of UAVs may be configured to determine their location by means of at least one of communication from a satellite navigation system and short-range communication between the at least someUAVs. However, each UAV of the plurality of the UAVs may be configured to determine its location by means of at least one of communication from the satellite navigation system and short-range communication between the UAVs. Knowing the locations and/or the relative positions of at least some of the UAVs of the plurality of UAVs may increase the controllability of the plurality of UAVs. The satellite navigation system may be a Global Navigation Satellite System, GNSS, such as, for example, GPS or 5G. The short-range communication may be, for example, Ultra Wide Band, UWB, communication or ultrasonic communication.

The plurality of UAVs may be configured to use an autonomous positioning system, which may be based on UWB communication. The autonomous positioning system may allow for the plurality of UAVs to determine where they are located with regards to each other, which may provide a more detailed relative positioning than what is possible with a GNSS. A more detailed relative positioning may reduce the risk of the plurality of UAVs working against each other, i.e. flying in different directions, since they are interconnected via the water hose. Further, an autonomous positioning system may allow for operating in environments in which radio communication or GNSS are limited. Thus, the availability of the arrangement may be increased.

The fire extinguishing arrangement may further comprise at least one communication cable arranged along the water hose. Thus, the at least one communication cable may be arranged inside, or outside, of the water hose. The at least one communication cable may be configured for communicatively connecting the plurality of UAVs to the control unit. Communication via at least one communication cable may be faster and/or more reliable than wireless communication. Thus, the reliability and/or efficiency of the arrangement may be improved. The plurality of UAVs and the control unit may be configured to communicate over Ethernet via the at least one communication cable, wherein a data transfer rate of the communication may be above 0.1, 1, 10 or 100 gigabits per second. However, the arrangement isnot limited to being controlled over Ethernet. For example, other standardized protocols may be used, such as SPI, CAN, or RS- At least one of a shape and a size of an opening of a nozzle of the plurality of nozzles may be adjustable. ln other words, the shape and/or size of an opening of a nozzle may be adjustable. For example, a size of an opening of a nozzle may be increased or decreased. According to another example, a section of an opening may be blocked, such that the shape of the opening is adjusted. By changing the shape and/or size of the opening, the characteristics of the water discharged from the hose may be altered in order to most efficiently suppress or extinguish a current (wild-)fire. Thus, the efficiency of the arrangement may be increased.

Alternatively, at least one nozzle of the plurality of nozzles may be interchangeable, or replaceable. Therefore, plurality of nozzles may be chosen to best suit the needs of a particular (wild-) fire. Thus, the fire suppression ability of the arrangement may be increased.

The arrangement may be configured to control and/or steer the nozzles. ln other words, the direction of water discharging through a nozzle may be controlled by the arrangement. Further, the arrangement may be configured to control each nozzle individually, which may allow for different nozzles of the arrangement to target different sorts of fires. For example, some nozzles may discharge water mist, or spray, in order to provide efficient cooling of an area, while other nozzles may discharge streams of water in order to focus water into a seat of the fire.

A nozzle of the plurality of nozzles may be configured as a spray nozzle. Any number of nozzles of the plurality of nozzles, for example all of the nozzles, may be configured as spray nozzles. The spray nozzle(s) may be configured to discharge the water from the water hose as a water mist, or spray. Water mist, or spray, may comprise characteristics which are beneficial when suppressing, or extinguishing, certain kinds of (wild-)fires. Additionally, water mist, or spray, may be more efficient with regards to water usage. Thus, if theavailable amount of water is limited, spray nozzles may increase the efficiency of the arrangement.

The power cabling may be arranged to be surrounded by water inside the water hose during operation of the fire extinguishing arrangement. For example, the power cabling may be arranged towards a middle of the water hose, such that water may flow around the power cabling. Therefore, a contact area between the power cabling and the water inside the water hose may be maximized, which may increase the efficiency of the cooling of the power cabling. Thus, the efficiency of the arrangement may be increased.

The power cabling may be integrated with the water hose. For example, power cabling may be woven into water hose. ln another example, the power cabling may be arranged along an inner surface of the water hose.

The water hose may comprise a foldable and/or bendable material. Therefore, the water hose may be easier to store when not in use, which may improve the transportability of the water hose. Thus, the availability of the arrangement may be increased. For example, the water hose may comprise a fabric material. The water hose may comprise a woven material. Further, the water hose may comprise a plurality of materials, wherein the plurality of materials may be layered.

The power cabling may be configured for a voltage above 350V. A higher voltage results in a lower current which reduces the resistive losses in the power cabling, which may increase the efficiency of the arrangement. The plurality of UAVs may need to be supplied with power at a required power level. Therefore, power cabling being configured for a voltage above 350V may allow for power cabling with a smaller total cross-sectional area, which would have a reduced resistance, to deliver current to the plurality of UAVs at, or above, the required power level. Further, reducing the total cross-sectional area of the power cabling reduces the weight of the power cabling, which may reduce the required lifting power required by the plurality of UAVs. Furthermore, a reduced required lifting power may reduce the need for electrical energy for the plurality of UAVs, which may reduce the required power level. ln other words, a positive feedback loop is obtained. Additionally, the power cabling may be configured for a voltage above 500V or above 900V. A total cross-sectional area of the power cabling may be less thanmm lt is of interest to reduce the current in the power cabling since the resistive losses are proportional to the resistance of the power cabling and the square of the current. Thus, reducing the total cross-sectional area of the power cabling and using a high voltage, such as above 350V, has a synergistic effect of reducing the resistive losses. Further, increasing the voltage may allow for using longer water hoses, which would increase the accessibility of the arrangement.

The water hose may have an internal diameter which is less than 35mm. ln order for a water hose to be able to transport the same amount of water as another water hose, which has a larger internal diameter as the water hose, the water pressure inside the water hose has to be higher than the water pressure inside the other water hose. Further, it is of interest to reduce the weight of the water hose, and the water inside the water hose, during operation of the arrangement. Thus, by providing a water hose with a smaller internal diameter, such as less than 35mm, the efficiency of the arrangement may be increased. Consequently, a water hose which has an internal diameter which is less than 35mm may be operated at a high water pressure, when compared to another water hose which has a diameter which is greater than 35mm. The high water pressure may be, for example, above 10 bar, 20 bar or 30 bar. Thus, the high water pressure may be, for example, above 1000 kPa, 2000 kPa, or 3000 kPa. An increased pressure may allow for a finer water spray, or mist, which may provide a higher fire suppression ability. Additionally, an increase pressure may provide a greater stiffness and/or stability of the water hose. The water hose may be configured to receive water from the water pump, wherein the water has a water pressure of at least 20 bar. Thus, the water hose may be configured to receive water from the water pump, wherein the water has a water pressure of at least 2000 kPa.The water hose may have a length which is greater than 300 meters. Therefore, the arrangement may be configured to provide fire suppression and/or extinguishing up to 300 meters away. However, as the water hose may have to be lifted to heights of, up to, 100 meters, depending on the (wild-) fire, the distance to which it may provide fire suppression and/or extinguishing may vary. The height to which the water hose has to be lifted may be dependent on the heat of the (wild-) fire. However, a longer water hose allows for an increased capacity.

The plurality of UAVs may comprise batteries. The batteries may be configured for supplying the plurality of UAVs with electrical energy for lifting at least the at least a portion of the water hose. The batteries may allow for the plurality of UAVs to operate, at least for a relatively short period of time such as, for example 5, 10, 15, or 30 minutes, without being supplied with power via the power cabling. Thus, the water hose could, for the relatively short period of time, be disconnected. By the water hose being able to be disconnected, the system may allow for extending the water hose with an extending portion of water hose whilst maintaining operation of the plurality of UAVs. For example, the plurality of UAVs may be supplied with electrical energy by the batteries, while the water hose is disconnected and an extending portion of water hose is connected to the water hose, after which the plurality of UAVs may again be configured to receive electrical energy via the power cabling. Further, the batteries may be configured to adjust the electrical energy supplied to an UAV, in case of a fluctuation of electrical energy delivered via the power cabling. Thus, the batteries may increase the redundancy of the arrangement.

A UAV of the plurality of UAVs may comprise a plurality of rotors configured for lifting said UAV. The plurality of rotors may comprise four or less rotors, such as one, two, three or four. Moving a larger amount of air slowly is more efficient than moving a smaller amount of air quickly. Thus, using fewer and/or larger rotors may increase the efficiency of a UAV. For example, aUAV may comprise one single rotor, wherein blades of the single rotor are configured to be dynamically angled during a revolution.

At least one of the water pump and the electrical energy source of the system may be arranged at ground level. ln other words, the system's water pump and/or electrical energy source may be arranged at ground level. The water pump may be electrically connected to the electrical energy source, and the electrical energy source may be configured to provide electrical energy to the water pump.

The system may further comprise at least one additional water pump. An additional water pump may be arranged along the water hose. An additional water pump may be configured to receive electrical energy via the power cabling. An additional water pump may be configured to increase the water pressure inside the water hose. Thus, an additional water hose may allow for a longer and/or thinner water hose.

The system may further comprise a water supply system. The water supply system may comprise a supply pump and at least one supply hose. The water supply system may be connected to the water pump and may be configured to provide the water pump with water from a water supply source. The at least one supply hose may be arranged along ground or substantially at ground level. Therefore, the pressure needed to transport water from the water supply source may be lesser than the pressure inside the water hose. The water supply system may allow for fire suppression and/or extinguishing further away from a water source. Thus, the availability of the system is increased. For example, the water supply system may be able to provide the water pump with water from a water supply source which is located hundreds of meters away from the water pump. lt is noted that other embodiments using all possible combinations of features recited in the above described embodiments may be envisaged. Thus, the present disclosure also relates to all possible combinations of features mentioned herein.Brief description of drawings Exemplifying embodiments will now be described in more detail, with reference to the following appended drawings: Figure 1 is a schematic illustration of a fire extinguishing arrangement. Figure 2 is a schematic illustration of a system for fire extinguishing.

As illustrated in the figures, the sizes of the elements and regions may be exaggerated for illustrative purposes and, thus, are provided to illustrate the general structures of the embodiments. Like reference numerals refer to like elements throughout.

Detailed description Exemplifying embodiments will now be described more fully hereinafter with reference to the accompanying drawings in which currently preferred embodiments are shown. The invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided for thoroughness and completeness, and fully convey the scope of the invention to the skilled person. Figure 1 shows a fire extinguishing arrangement The arrangement 1 comprises a water hose 10. The water hose 10 is configured to be connected to a water pump (not shown; see Figure 2) and to receive water from the water pump. The arrangement 1 comprises a plurality of nozzles 20 arranged on a portion 11 of the water hose 10, wherein Figure 1 shows two nozzles 20. However, it is to be understood that the arrangement 1 may comprise any number of nozzles 20. The nozzles 20 are configured to receive water from the water hose 10 and to discharge the received water.

An internal diameter of the water hose 10 may be less than 35mm. However, it is to be understood that the arrangement 1 shown in Figure 1 is drawn in order to facilitate an increased understanding of the present disclosure, and is thereby not necessarily drawn to scale. Thus, the relative size of the othercomponents of the arrangement 1 may not be determined based on the water hose 10 having an internal diameter which may be less than 35mm.

The arrangement 1 further comprises a plurality of UAVs 30, wherein Figure 1 shows two UAVs 30. However, it is to be understood that the arrangement 1 may comprise any number of UAVs 30. The UAVs 30 are connected to the water hose 10 and are configured to lift at least the portion 11 of the water hose 10. ln Figure 1, the UAVs 30 are shown to be arranged at a distance above the water hose 10, but the present disclosure is not limited to such an arrangement. For example, the UAVs 30 may be arranged on the water hose 10. Further, the UAVs 30 may be arranged below the water hose 10, such that they are configured to lift the water hose 10 from below rather than carry the water hose 10 from above.

The UAVs 30 each comprises two rotors 31 arranged on opposite sides of the UAV 30. However, the UAVs 30 may comprise any number of rotors 31, such as one, two, three, four, five, six, seven, or eight. Further, the rotors 31 may be arranged on any of the sides, top, or bottom of the UAVs ln the exemplary embodiment shown in Figure 1, each UAV 30 is arranged on an opposite side of the water hose 10 with respect to a respective nozzle 20. Therefore, a UAV 30 may be configured control and/or steer, i.e. to aim, a respective nozzle 20. However, the UAVs 30 and the nozzles 20 may be arranged in a different manner. For example, there may more nozzles 20 than UAVs 30, or more UAVs 30 than nozzles 20. lf there are more nozzles 20 than UAVs 20, at least some of the nozzles 20 may be arranged on the water hose 10 between two neighboring UAVs 30. lf there are more UAVs 30 than nozzles 20, a nozzle 20 may be arranged at, for example, every other UAV The arrangement 1 further comprises power cabling 40. The power cabling 40 is arranged within the water hose 10. The power cabling 10 is configured to be cooled by water inside the water hose 10. ln Figure 1, the power cabling 40 is arranged along a middle of the water hose 10. Thus, the power cabling 40 is arranged to be surrounded by water flowing through the water hose 10, thereby increasing the cooling potential. However, the arrangement 1 of the power cabling 40 is not limited to the exemplary embodiment as shown in Figure 1. For example, the power cabling 40 may be arranged along an internal surface of the water hose 10 or integrated with the water hose 10. The power cabling 40 is electrically connected to the UAVs 30. ln Figure 1, a section of the power cabling 40 is connected to a respective UAV 30 through the water hose 40. However, the power cabling 40 may be connected to UAVs 30 in a different manner. For example, if the UAVs 30 are arranged, or attached, onto the water hose 40, a connector of an UAV 30 may be arranged through the water hose 40, wherein the power cabling 40 is connected to the UAV 30 via the connector of the UAV The arrangement 1 further comprises communication cables 55. The communication cables 55 are configured for communicatively connecting the UAVs 30 to a control unit (not shown; see Figure 2). The communication cables 55 are arranged within the water hose 10, wherein the communication cables 55 are arranged analogously as the power cabling 40. However, the communication cables 55 may be arranged differently from the power cabling 40. For example, the communication cables 55 may be arranged on an outside of the water hose 10. Further, the arrangement 1 is not limited to comprising communication cables 55, and the UAVs 30 may be communicatively connected to the control unit wirelessly.

Connections through the water hose 10, to the UAVs 30 and the nozzles 20, may be sealed, such that they are water tight. Further, the sealed connections through the water hose 10 may be configured to withstand a pressure above 100 bar.

The nozzles 20 shown in Figure 1 are an exemplary embodiment. The nozzles 20 may be configured as spray nozzles. The nozzles 20 comprises at least one opening, wherein the shape and/or size of an opening determines the characteristics of profile of the water discharged through the opening. A nozzle 20 may comprise any number of openings, wherein the number may be between one and hundred. The shape and/or the size of an opening of anozzle 20 may be adjustable. For example, a nozzle 20 may comprise a movable part, or shutter, which is configured to limit a portion of an opening, thereby adjusting the shape and/or size of the opening.

According to an exemplary embodiment, the nozzles 20 may be configured as pipes, wherein the pipes may comprise a plurality of openings which may be arranged along a length of a pipe. Figure 2 is a schematic illustration of a system 100 for fire extinguishing.

The system 100 comprises a fire extinguishing arrangement 1. The fire extinguishing arrangement 1 shown in Figure 2 may correspond to the fire extinguishing arrangement 1 shown in Figure 1 and described in the text referencing Figure The arrangement 1 comprises four UAVs 30 arranged along a portion 11 of a water hose 10. The arrangement 1 further comprises four nozzles 20, each arranged below a respective UAV 30. However, as stated in the text referencing Figure 1, the arrangement 1 is not limited to the number of UAVs 30 or nozzles 20 shown, and may be, substantially, any number.

The system 100 further comprises a water pump 15 and an electrical energy source 45. The water pump 15 is connected to the water hose 10 of the arrangement 1. The water pump 15 is configured to pump water into the water hose 10. The water pump 15 may be configured to pump the water with a pressure of at least 10 bar.

The electrical energy source 45 is configured to supply electrical energy to the power cable (not shown; see Figure 1) of the arrangement 1. The electrical energy source 45 may be configured as a generator, or as a power grid. The electrical energy source 45 may be configured to supply electrical energy with a voltage above 350V.The electrical energy source may be configured to supply alternate current, AC, or direct current, DC.

The electrical energy source 45 is further electrically connected to the water pump 15 is configured to supply the water pump 15 with electrical energy.The system 100 further comprises a water supply system 70. The water supply system 70 comprises a supply pump 75 and two supply hoses 71. One of the supply hoses 71 is connected between the supply pump 75 and the water pump 15 and is configured to transport water from the supply pump 75 to the water pump 15. The other supply hose 71 is connected to the water supply pump 75 and arranged to allow water to be pumped from a water supply source 80. The water supply source 80 is shown in Figure 2 as a lake, but it may also be, for example, a river, a sea, or a (local) water network. Thus, the water supply system 70 is configured to provide the water pump 15 with water from the water supply source 80. The water supply system 70 may be arranged differently. For example, the water supply pump 75 may be arranged at the water supply source 80 or at the water pump 15, thereby only needing one water hose 71 _ The portion 11 of the water hose 10 is shown as being lifted by the UAVs 30 above a forest fire 90. The nozzles 20 may be aimed, and are arranged to discharge water, towards the forest fire 90, wherein the water is received via the water hose 10. Another portion of the water hose 10 is arranged between the water pump 15, which is arranged at a ground level, and the portion 11 of the water hose The UAVs 30 are being controlled by a user via a control unit 50. The shown control unit 50 is a handheld device. However, the control unit 50 may be any kind of electronic device configured for controlling UAVs 30. The control unit 50 may be configured to communicate with the UAVs 30 via a wire 51. The wire 51 may be connected to communication cables (not shown; see Figure 1) arranged along the water hose 10. Alternatively, the control unit 50 may be configured to communicate with the UAVs 30 via a wireless interface 52. Further, the control unit 50 may be configured to communicate with the UAVs 30 via either, or both, of the wire 51 and the wireless interface 52, which may thereby increase the redundancy of the system The present disclosure is not limited to the UAVs 30 being controlled by a user who is physically present, or close to, the system 1. The control unitmay be configured to be controlled remotely. For example, the control unit 50 may be configured to allow a remote login, wherein the remote login may be accessed via, for example, satellite, LTE, 3G, 4G or 5G communication. Thus, a user, i.e. an operator, of the system 1 does not have to be physically present to control the system 1. Further, it allows for a single user to monitor multiple systems The person skilled in the art realizes that the present invention by no means is limited to the preferred embodiments described above. On the contrary, many modifications and variations are possible within the scope of the appended claims.

Although features and elements are described above in particular combinations, each feature or element can be used alone without the other features and elements or in various combinations with or without other features and elements.

Additionally, variations to the disclosed embodiments can be understood and effected by the skilled person in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. ln the claims, the word "comprising" does not exclude other elements, and the indefinite article "a" or "an" does not exclude a plurality. The mere fact that certain features are recited in mutually different dependent claims does not indicate that a combination of these features cannot be used to advantage.

Claims

1. A fire extinguishing arrangement (1) comprising a water hose (10) configured to be connected to a water pump (15) and to receive water from the water pump; a plurality of nozzles (20) arranged on at least a portion (11) of the water hose, wherein the plurality of nozzles is configured to receive water from the water hose and to discharge said received water; a plurality of unmanned aeria| vehicles, UAVs, (30) connected to the water hose and configured to lift at least the at least a portion of the water hose; power cabling (40) arranged within the water hose and electrically connected to the plurality of UAVs, wherein the plurality of UAVs is configured to receive electrical energy from an electrical energy source (45) via the power cabling, and wherein the power cabling is configured to be cooled by the water inside the water hose.

2. The fire extinguishing arrangement according to claim 1, wherein the plurality of UAVs is configured to be communicatively connected to a control unit (50) which is configured for controlling the plurality ofdrones.

3. The fire extinguishing arrangement according to claim 2, further comprising at least one communication cable (55) arranged along the water hose and configured for communicatively connecting the plurality of UAVs to the control unit.

4. The fire extinguishing arrangement according to any of the preceding claims, wherein at least one of a shape and a size of an opening of a nozzle of the plurality of nozzles is adjustable. »v The fire extinguishing arrangement according to any of the preceding claims, wherein the power cabling is configured for a voltage above 350V.The fire extinguishing arrangement according to any of the preceding claims, wherein the water hose has an internal diameter which is less than 35mm. The fire extinguishing arrangement according to any of the preceding 20 claims, wherein the water hose is configured to receive water from the water pump, wherein the water has a water pressure of at least 20 bar. A system (100) for fire extinguishing comprising: a fire extinguishing arrangement according to any of the preceding 25 claims, a water pump (15) connected to the water hose, configured to pump water into the water hose, and an electrical energy source (45) configured to supply electrical energy to the power cable. The system according to claim further comprising: a water supply system (70) comprising a supply pump (75) and at least one supply hose (71), wherein the water supply system is connected to the water pump and is configured to provide the water pump with water from a water supply source (80).