Method of extinguishing fires by air blast

Abstract

This invention discloses a method for extinguishing fires using air blasts, belonging to the field of fire protection technology. This method employs distributed air blast generation units as the core fire extinguishing means. Several paper-cased units containing gunpowder are deployed to the target area of ​​the fire scene via drone swarms, aircraft, or manual methods, forming a two-dimensional or three-dimensional air blast generation matrix. Each unit has a built-in composite fuse system, supporting multiple detonation methods such as radio remote control, time delay, thermal sensitivity, and shock wave linkage, enabling simultaneous detonation, cascaded detonation, or autonomous thermal triggering. The fire is extinguished through the superposition effect of dense air blasts. This invention also provides optional modular air cannons as auxiliary tools for clearing stubborn embers. This method is particularly suitable for large-scale firefighting of forest and grassland fires, offering advantages such as high safety, large-scale deployment, environmental friendliness, low cost, and the ability to handle three-dimensional fires.

Description

Technical Field

[0001] This invention relates to the field of fire protection technology, and more specifically, to a method for extinguishing fires using distributed air wave generating units, which is particularly suitable for large-scale firefighting operations in forest fires, grassland fires, and complex terrain conditions.

[0002] Background Technology: Forest fires are characterized by their sudden onset, rapid spread, and difficulty in control. Traditional firefighting methods include manual battering, covering with soil, water spraying, and chemical extinguishing agent spraying. However, in areas with intense fires or steep terrain, firefighters have difficulty accessing the core of the fire, resulting in low firefighting efficiency and significant safety hazards.

[0003] In recent years, the concept of using explosive shockwaves to extinguish fires has emerged, such as deploying explosive charges to extinguish flames using the resulting blast wave. However, existing technologies have the following drawbacks: First, they often use metal casings or warheads, which produce high-speed fragments upon explosion, easily causing injury to personnel and potentially igniting surrounding unburned areas; second, the effective range of a single-point explosion is limited, making it difficult to deal with large-area fires; third, the detonation method is singular, making it impossible to achieve large-scale coordinated detonation; fourth, the devices are costly and heavy, making large-scale aerial delivery inconvenient. To address these issues, there is an urgent need for a safe, efficient, and large-scale deployable pure blast wave fire extinguishing method.

[0004] The present invention aims to provide a method for extinguishing fires using air blasts, thereby addressing the problems mentioned in the background art. This method utilizes a large-scale deployable distributed air blast generating unit to form an air blast matrix in the target area of ​​the fire, extinguishing the fire through the superposition effect of dense air blasts.

[0005] This invention is achieved through the following technical solution:

[0006] A method for extinguishing fires using blast wave technology involves deploying several independent blast wave generating units to the target area of ​​a fire using a delivery device. Each blast wave generating unit is a paper casing containing gunpowder. The blast wave generating units are simultaneously or delayedly detonated by a fuse device. The diffuse high-pressure blast wave generated at the moment of explosion impacts the flames, disrupting the stable combustion conditions and thus extinguishing the fire.

[0007] As a further description of the technical solution, the air wave generating unit forms a two-dimensional or three-dimensional air wave generating matrix at the fire front, the core area of ​​the fire, or the predetermined fire-blocking zone through methods such as drone swarms, manual dropping, mechanical spreading, or aircraft dispersal. In this matrix, the spacing between adjacent air wave generating units is determined based on their charge amount and expected radius of effect to achieve seamless coverage or directional superposition of air waves. Specifically, when a continuous fire-blocking zone is required, the unit spacing is set to be less than one radius of effect to ensure overlapping air wave coverage areas; when a directional impact is required, the unit spacing is set to be equal to or slightly greater than one radius of effect, utilizing the convergence effect of multiple air waves to enhance the impact force in a specific direction.

[0008] As a further description of the technical solution, the air blast generating unit uses fully degradable paper material as its shell, and is filled with gunpowder ranging from tens to hundreds of grams. Depending on the fire intensity, units of different equivalents can be selected: small-equilibrium units with tens to fifty grams of gunpowder are used to extinguish surface fires and clear remaining embers; medium-equilibrium units with fifty to two hundred grams of gunpowder are used to extinguish shrub fires and block fire lines; large-equilibrium units with two hundred to several hundred grams of gunpowder are used to extinguish crown fires and create firebreaks. The paper shell is treated with a waterproof process, allowing it to maintain structural integrity and gunpowder performance in humid environments or under short-term rainfall conditions.

[0009] As a further description of the technical solution, the air wave generating unit has a built-in composite fuse system, which simultaneously possesses one or more of the following detonation methods: The first is radio remote control detonation, used to achieve precise control of cluster detonation, where the ground command system can send detonation commands to individual or group units; the second is time-delay detonation, used for pre-deployment and timed detonation, with the delay time preset according to the fire spread speed before deployment; the third is thermal detonation, which automatically detonates when the ambient temperature reaches a set threshold, giving it the characteristics of an intelligent landmine, capable of autonomously triggering when the fire spreads to the area, with the threshold temperature typically set between 150 and 300 degrees Celsius; the fourth is shock wave linkage detonation, where the detonation of adjacent units triggers subsequent units through shock waves, forming a cascade reaction, with the sensitivity of the shock wave linkage fuse set to respond only to near-range explosions to avoid false triggering.

[0010] As a further description of the technical solution, the air wave generating units can be deployed at different heights based on the three-dimensional characteristics of the fire scene. Surface deployment is used to extinguish ground fires; units are directly placed on the ground or shallowly buried beneath layers of dead branches and leaves. Units deployed in the canopy layer are dropped by drones via hovering or landing to extinguish crown fires. Units deployed in the canopy layer can be equipped with miniature descent devices or suspension systems, allowing them to be attached to tree branches to form a three-dimensional fire suppression network. Through coordinated deployment in the surface and canopy layers, comprehensive coverage of three-dimensionally spreading fires is achieved.

[0011] As a further description of the technical solution, a directional air cannon can be used as an auxiliary means to extinguish specific stubborn fires or residual fires at high altitudes. The air cannon concentrates combustible gas through its barrel to create an explosive wave, precisely supplementing the fire source. This air cannon has a modular, disassembled structure, including a quickly detachable barrel module, ignition module, gas supply module, and support module. The barrel module consists of multiple lightweight tube sections that can be detachably connected by threads or snap-fits. In marching mode, it can be disassembled into a short tube that a single soldier can carry, and in combat mode, it can be quickly assembled to form the effective barrel length. The gas supply module uses a small gas cylinder filled with propane, acetylene, or a special mixed gas, and connects to the ignition module via a high-pressure hose and a self-sealing quick-connect fitting. The ignition module integrates an electronic igniter, a mixing valve, and control circuitry, enabling single or continuous firing. This air cannon, as an auxiliary means, forms a complete fire extinguishing system with a paper cannon matrix, providing both area coverage and point-clearing capabilities.

[0012] Compared with the prior art, the beneficial effects of the present invention are:

[0013] First, it is highly applicable in actual combat. Adopting a distributed deployment concept, it can cover several hectares of fire area at once, solving the problem of low efficiency of traditional single-point fire extinguishing devices. Through drone swarm operations, hundreds of units can be deployed in a single flight, forming a kilometer-level firebreak.

[0014] Secondly, it boasts high safety. Utilizing a pure paper shell, it produces no metal fragments upon explosion, completely eliminating secondary injuries. Firefighters can deploy and detonate it from a safe distance within the fire zone, without needing to enter high-risk areas.

[0015] Third, it has a high degree of intelligence. The composite fuse system enables the unit to autonomously trigger upon receiving fire, and can automatically respond to the spread of fire without human intervention, thus solving the problem of slow response speed in manual detonation.

[0016] Fourth, it is environmentally friendly and pollution-free. The paper casing is completely biodegradable, and the gunpowder products are mostly gases such as carbon dioxide and water vapor, which have minimal impact on the original forest ecosystem and do not leave any chemical extinguishing agent residues.

[0017] Fifth, low cost. Paper firecrackers have a simple structure and can be mass-produced industrially, keeping the cost per firecracker low. This makes them suitable for large-scale stockpiling and consumption during peak fire seasons.

[0018] Sixth, three-dimensional fire suppression capability. Through multi-layer deployment at the ground and canopy levels, it can simultaneously address both surface and canopy fires, solving the problem of fighting forest fires spreading in three dimensions and filling the gap in existing technologies that are unable to extinguish canopy fires.

[0019] The specific embodiments of the present invention will be clearly and completely described below.

[0020] Example 1: Drone swarm deploys paper cannons to extinguish surface fires

[0021] A surface fire broke out in a forest farm. The fire line was about 500 meters long and spread in a southeast direction. The wind speed was level 3 to 4 and the fire head was about 1.5 meters high. It is a typical medium-sized surface fire.

[0022] The operation utilizes a cluster of six hexa-rotor agricultural drones, each carrying thirty air blast generators. Each generator uses a waterproof paper cylinder as its shell, with a diameter of 80 mm and a length of 150 mm. It is filled with 50 grams of ammonium nitrate gunpowder and has a radio remote control receiver fuse on top. The shell material is multi-layered composite cardboard, treated with paraffin wax, allowing it to maintain its waterproof performance for four hours in light rain.

[0023] The drone swarm flew to an unburned area approximately 100 meters in front of the fire and precisely deployed drones according to a pre-set layout plan from the ground command system, using a grid density of 2 meters by 2 meters. The deployment path was designed perpendicular to the direction of fire spread, forming a rectangular blast wave generation matrix 50 meters wide and 500 meters long along the fire's path. The entire deployment process took eight minutes, with a total of 180 drone units deployed.

[0024] When the fire line reached approximately ten meters from the edge of the matrix, the ground commander issued a cluster detonation command via radio transmitter. All units detonated simultaneously, and the resulting dense blast waves superimposed, creating a short-term high-pressure zone in the area, with peak shock wave pressures reaching five to eight thousand Pascals. This pressure was sufficient to disperse the layer of dead leaves and branches on the ground and blow flames away from the surface of combustible materials. Simultaneously, the localized low-pressure zone behind the shock wave caused air recirculation, further isolating oxygen. The fire line was extinguished instantly by the shock wave. On-site inspection revealed that the leading edge of the fire line was completely extinguished, and the unburned area behind the firebreak remained intact, with no secondary ignition observed. The remaining paper casing was completely shattered and is expected to degrade naturally during subsequent rainfall.

[0025] Example 2: Intelligent Deployment and Cascaded Initiation of Composite Fuzes

[0026] For forest fires in mountainous areas with complex terrain, a composite fuse strategy was adopted. The area has a slope of about 30 degrees, and the vegetation consists mainly of shrubs and dry grass, making it difficult for personnel to enter.

[0027] Two hundred lightweight airburst generating units, each weighing 30 grams, were selected, equipped with a built-in dual-mode fuse combining thermal and radio detonators. The thermal fuse was set to trigger at 200 degrees Celsius, and the radio detonator operated at 430 MHz. Large-area seeding was conducted using manned helicopters at an altitude of 50 meters and a speed of 60 kilometers per hour, creating irregular firebreaks 30 meters wide on both sides of the ridgeline downwind of the fire. The seeding density was approximately one unit per square meter, adjusted locally according to vegetation density.

[0028] When the wildfire spreads to the area, the thermal radiation from the fire front raises the ambient temperature of the leading fire unit to a set threshold, triggering automatic detonation. The shockwave generated by the detonation extinguishes localized flames and simultaneously acts on the shockwave-linked fuses of adjacent units. These fuses utilize piezoelectric sensors, designed to respond to pressures exceeding 50 kPa. This sensitivity ensures that they only react to nearby explosions, preventing accidental triggering by distant sounds. After the first unit detonates, the shockwave triggers adjacent units within a 3-5 meter radius within 0.1 seconds, creating a self-propagating cascade detonation reaction that rapidly spreads along the firebreak. This outpost-detonation, follow-up-detonation mode automatically responds to the advancing fire line without human intervention, significantly improving fire suppression response speed. Actual measurements show that the cascade propagation speed is approximately 200 meters per second, completing the detonation of the entire firebreak within seconds.

[0029] Example 3: Using a three-dimensional fire suppression network to extinguish crown fires

[0030] For crown fire, the most difficult type of forest fire to extinguish, a three-dimensional deployment strategy was adopted. The fire site was in a coniferous forest area with trees 15 to 20 meters tall. The crown fire spread at a speed of about 5 meters per second, accompanied by a large number of flying embers.

[0031] Two types of air blast generating units were selected: Type A, with an 80-gram charge, a 100-millimeter shell diameter, and a 200-millimeter length, was used for ground deployment; Type B, with a 50-gram charge, a 60-millimeter shell diameter, and a 120-millimeter length, was equipped with a miniature parachute descent device and was used for canopy deployment. When the Type B unit was deployed, the parachute automatically opened, causing the unit to descend slowly and attach to branches in the canopy, preventing it from falling directly to the ground.

[0032] The drone swarm operates in two batches: the first batch flies at a height of 15 meters and drops Type B units 50 meters in front of the fire line, dropping one unit every three meters to form a canopy layer; the second batch flies at a height of 2 meters and drops Type A units in the same projection area, dropping one unit every two meters to form a ground layer. The two layers of units are staggered in the vertical projection to avoid mutual occlusion.

[0033] After deployment, all units were detonated simultaneously. The shockwave from the surface units impacted upwards, while the shockwave from the canopy units diffused downwards. These shockwaves converged and superimposed in space, forming a completely enclosed high-pressure zone from the ground to the top of the canopy. The peak pressure of the shockwave in the canopy layer reached over 3,000 Pascals, sufficient to disperse flames on the surface of the canopy branches and leaves. Simultaneously, the high-pressure zone lasted for approximately 0.5 seconds, completely cutting off the vertical oxygen supply. On-site observations showed that the canopy fire, reaching a height of 20 meters, was completely extinguished within three seconds of detonation, leaving only scorch marks on the trunk and no reignition. This method solves the technical problem of traditional firefighting methods being unable to effectively extinguish canopy fires.

[0034] Example 4: Air cannon-assisted removal of stubborn fire spots

[0035] After the main fire of the fire-fighting matrix is ​​extinguished, some hidden fire spots may not be completely extinguished. These fire spots are usually located inside fallen logs, in rock crevices, or deep in humus layers, and are difficult to remove by conventional means.

[0036] A modular air cannon is used for precise supplementary strikes. This air cannon is a portable device based on the existing electronic salute cannon structure, and adopts a detachable modular design: the cannon barrel is divided into three sections, each 500 mm long and 150 mm in inner diameter, connected by quick-connect threads, with a total length of 1,500 mm after assembly; the air supply module is a two-liter propane cylinder with a working pressure of 0.8 MPa, connected to the breech via a quick-connect connector; the ignition module integrates a high-energy electronic igniter, a proportional mixing valve, and a lithium battery, with a total weight of 18 kg, which can be carried to the fire scene by a single person.

[0037] Operators carry the disassembled air cannon components into the fire scene and complete the barrel assembly, gas cylinder connection, and support setup within one minute. After aiming at the concealed fire point, the trigger is pulled. The microcomputer controller within the ignition module automatically calculates the required gas volume based on the barrel volume and controls the solenoid valve to fill the barrel with a mixture of propane and air, maintaining the mixing ratio within the explosive limit range of 4% to 8%. 0.8 seconds after charging, the electronic igniter generates a high-voltage spark to ignite the mixture. The explosive gas wave is then ejected directionally from the muzzle, forming a high-speed jet approximately 300 mm in diameter and 10 meters in length. This jet can directly penetrate crevices in fallen logs or rock layers, dispersing and extinguishing concealed fire sources. If the fire is not extinguished in one attempt, a second charge and firing can be performed immediately, achieving a continuous firing rate of 1.5 rounds per second.

[0038] The air cannon, used as an auxiliary means, works in conjunction with the main fire suppression array to form a complete fire extinguishing system that combines area coverage with targeted suppression. In Example 3, after extinguishing the crown fire, the air cannon was used to clear the remaining embers from three fallen trees, taking approximately two minutes per location, completely eliminating the risk of reignition.

[0039] Example 5: Large-scale aerial seeding fire suppression operation

[0040] In response to the massive forest fire, manned aircraft were used for large-scale seeding. The fire area was approximately 500 hectares, with a total fire line exceeding 10 kilometers in length, making it difficult for conventional ground forces to reach the site quickly.

[0041] 20,000 standard blast wave generating units, each with a charge of 100 grams, were selected, totaling approximately four tons. The seeds were spread using transport helicopters, employing roller-type metered spreaders installed at the helicopter's door. The helicopters flew at an altitude of 80 meters and a speed of 80 kilometers per hour, repeatedly spreading seeds along a predetermined firebreak. The seeding density was set at 0.5 units per square meter, forming a continuous firebreak 20 meters wide and 12 kilometers long, located 3 kilometers downwind of the fire, serving as a strategic firebreak.

[0042] All units are equipped with thermal fuses, with a trigger temperature uniformly set at 250 degrees Celsius. Additionally, several radio relay control points are installed at both ends and in the middle of the fire-resistant strip for manual intervention in detonation when necessary.

[0043] Driven by strong winds, the fire advanced towards the firebreak, reaching its edge eight hours later. Thermal radiation triggered the detonation of the leading-edge units, which then cascaded through the shockwave, causing detonations throughout the entire firebreak. The entire twelve-kilometer firebreak was detonated within approximately one minute, forming a continuous blast barrier. The fire line was extinguished entirely by the shockwave, successfully preventing the fire from spreading to surrounding villages and towns. Post-event assessments showed that this method offers a large coverage area per operation, rapid response, and low manpower requirements, making it suitable as a strategic reserve for national-level forest fire prevention.

[0044] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for extinguishing fires using blast wave, characterized in that: Several independent blast wave generating units are deployed to the target area of ​​the fire using a delivery device; each blast wave generating unit is a shell containing gunpowder; the blast wave generating unit is detonated by a fuse device, and the blast wave generated by the explosion impacts the flames.

2. The blast wave fire extinguishing method according to claim 1, characterized in that: The air wave generating unit is made of paper material.

3. The blast wave fire extinguishing method according to claim 1 or 2, characterized in that: The air wave generating unit forms a two-dimensional or three-dimensional air wave generating matrix at the fire front, the core area of ​​the fire, or the predetermined fire-blocking area by means of drone swarms, manual throwing, mechanical spreading, or aircraft spreading; in the matrix, the spacing between adjacent units is determined according to their charge amount and radius of action to achieve seamless coverage or directional superposition of air waves.

4. The blast wave fire extinguishing method according to claim 1 or 2, characterized in that: The air wave generating unit selects different equivalents according to different fire intensity requirements, and is used to extinguish surface fires, shrub fires or crown fires respectively.

5. The blast wave fire extinguishing method according to claim 1 or 2, characterized in that: The fuse device adopts a composite fuse system, which has one or more of the following initiation methods: radio remote control initiation, time delay initiation, thermal initiation, and shock wave linkage initiation.

6. The blast wave fire extinguishing method according to claim 5, characterized in that: The thermal detonation method enables the blast wave generating unit to automatically detonate when the ambient temperature reaches a set threshold.

7. The blast wave fire extinguishing method according to claim 5, characterized in that: The shock wave-linked detonation method enables adjacent units to form a cascade reaction triggered by shock waves.

8. The blast wave fire extinguishing method according to claim 1 or 2, characterized in that: The air wave generating units are deployed in a three-dimensional manner at different heights to form a three-dimensional fire extinguishing network that includes a ground deployment layer and a canopy deployment layer.

9. The blast wave fire extinguishing method according to claim 1 or 2, characterized in that: The directional air cannon is used as an auxiliary means to extinguish stubborn fires or residual fires at high altitudes; the air cannon gathers combustible gas explosion waves through the cannon barrel to accurately strike the fire source.

10. The blast wave fire extinguishing method according to claim 9, characterized in that: The air cannon has a modular, detachable structure, including a barrel module, an ignition module, an air supply module, and a support module that can be quickly disassembled and assembled.