RU2643637C1 - Method for fire fighting - Google Patents

Abstract

FIELD: fire safety.

SUBSTANCE: method firefighting, which consists in creating a fire-proof strip in front of a fire, into which an extinguishing medium is supplied. With the help of several successively moving delivery devices, each of which has its own spraying device, a liquid extinguishing medium is supplied in the form of several successively moving spray jets. Each successive jet consists of droplets with smaller radii than the previous one.

EFFECT: increase the fire extinguishing area.

3 cl, 1 dwg

Description

The invention relates to fire fighting equipment, and in particular to methods for extinguishing fires during fires over large areas, and can be used to localize and eliminate large forest fires, as well as when suppressing fires in industrial and public facilities.

A known method of extinguishing powerful local and other fires [RU 2281132 C2, IPC A62C 3/02 (2006.01), publ. 08/10/2006], in which a rotating fire-extinguishing mixture is brought down at a supersonic speed with a shock wave. The rotating extinguishing mixture is formed in the fire-extinguishing bomb delivered to the required position due to the first explosion of the cumulative charges placed in the bomb, while the supersonic speed of this mixture is reported by the second explosion of the charges placed in the bomb with recesses.

To implement this method requires a large amount of resources. This method is unsafe for people who accidentally find themselves in a fire zone, since the blast wave and subsequent balls with a fire extinguishing substance flying after it can lead to injuries or death. Balls with a fire extinguishing agent explode directly upon contact with objects of combustion. This only leads to a flood of burning objects. The spent liquid evaporates slightly, as a result, without significantly reducing the flame temperature.

A known method of extinguishing fires [RU 2295370 C2, IPC A62C 3/00, A62C 19/00, publ. March 20, 2007], based on the use of thin-walled sealed capsules filled with water, which deliver to the fire. The thermal energy of the fire is used to disperse the water contained in the capsules, and the size of the capsules is selected from the calculation of the occurrence of steam explosions of the capsules during their movement in the focus of the suppressed fire.

This method is difficult, and in some cases impossible to implement. Firstly, with the right choice of capsule shell for the implementation of the conditions for ensuring a steam explosion, it is necessary to know the characteristics of the fire: the temperature in the outbreak, the wind speed during open fire and combustion products, and the height of the fire. Secondly, when extinguishing small fires in height, the liquid inside the shell does not have time to warm up to realize a steam explosion and, as a result, the shell is destroyed by burning objects.

A known method of extinguishing horse and ground forest fires [RU 2146544 C1, IPC 7 A62C 3/02, publ. 03/20/2000], including the delivery of an explosive charge to a fire zone in an air bomb and its release during the interaction of a bomb fuse, for example, with the crowns of trees, while simultaneously releasing and spraying the extinguishing agent. An explosive charge in an air bomb is delivered using a platform provided for hanging 16 or more air bombs and made of metal structures with the possibility of connecting to delivery vehicles.

To implement this method, high costs are required, since extinguishing another fire requires a new set of specially prepared bombs. In addition, the device used to implement the method is unsafe, since the possibility of a false fuse when the bombs are suspended from a helicopter, as well as during their delivery to the fire site, is not ruled out.

A known method of extinguishing forest fires [RU 2375092 C1, IPC A62C 3/02, publ. December 10, 2009], selected as a prototype, in which a fire-retardant strip is created in front of the fire front, into which a fire-extinguishing medium is supplied in the form of a mixture of inert gas with aerosols, and dusty combustible and fire-resistant particles and air are used to produce inert gas and aerosols.

This method requires the use of a large amount of extinguishing agent and related sophisticated equipment for mixing the components of the composition and the subsequent generation of aerosol. The method is unsafe for people who accidentally find themselves in the zone of creating a fireproof strip.

The proposed method of extinguishing fires, as in the prototype, is to create a fire-retardant strip in front of the fire front into which a fire extinguishing medium is supplied.

According to the invention, by means of several successively moving delivery devices, each of which has its own spray device, a liquid extinguishing medium is supplied in the form of several successively moving spray jets, each successive stream consisting of drops with smaller radii than the previous one.

An aircraft can be used as a delivery device.

Water can be used as a liquid extinguishing medium.

The sequential supply of different streams of water with decreasing radii of the droplets makes it possible to effectively localize the fire due to the various extinguishing mechanisms characteristic of droplets of various sizes. The jet of water generated by the spray device with a large spray, knocks the flame by cooling the surface of the burning hearth. The subsequent stream of water with smaller droplet sizes overcomes the resistance of the flame and combustion products, reaches a burning surface and forms a film of water, removing a significant portion of the heat to evaporate the water. A jet of water moving next with even smaller droplets is actively evaporated in the flame area, and the resulting water vapor gradually displaces the oxidizer and gasification products from the combustion zone. With each subsequent cycle of movement of the spraying devices, the extinguishing effect is enhanced, which ultimately leads to the complete extinction of the fire.

The proposed method is safe for people who accidentally find themselves in a fire zone, and does not lead to pollution and destruction of the environment.

In FIG. 1 shows a diagram of creating a fire retardant strip when implementing the proposed method using three delivery vehicles.

To test the method of extinguishing fires at a landfill, in accordance with GOST R 51057-2001, a model fire center of type A1 was constructed from pine bars 50 × 50 mm. The model center was impregnated with TS-1 brand kerosene, after which it was ignited. The fire area was ≈1 m ² . The temperature of the combustion products and the flame was measured with chromel-alumel thermocouples complete with a multi-channel recorder РМТ-59М, it was ≈800 ° C.

A metal frame was installed above the model fire site at a height of about 1.5 m, on the guides of which there are three spraying devices connected to the tank with water. Each spray device, using an individual electric drive mounted on a frame, was moved along horizontal guides one after another over a model fire site. Nozzles were used as spraying devices: the first nozzle of the FE512-4-3 type generated a sprayed jet with droplet sizes of 2-5 mm; the second nozzle type TF0902 generated a sprayed jet with droplet sizes of 0.5-2 mm; the third nozzle type B661 / 40020 generated a spray jet with droplet sizes of 0.01-0.5 mm.

To control and record the size of water droplets in the sprayed jets generated by the nozzles, we used a diagnostic system for two-phase gas and vapor-liquid flows, operating on the basis of the optical methods Particle Image Velocimetry and Interferometric Particle Imaging (Volkov PC, G.V. Kuznetsov, Strizhak P.A. An experimental study of the completeness of evaporation of atomized water during its movement through a flame // Fire and Explosion Safety, 2013. - No. 10. - P. 15-24).

Each subsequent nozzle began to move along the horizontal guide after the previous one reached the edge of the fire. When the third nozzle reached the edge of the fire, the first nozzle began to move in the opposite direction. The process was repeated until the model site was completely quenched. The fact of quenching was recorded visually. Extinguishing was considered achieved if re-ignition did not occur within 10 minutes. After 120 s, the extinguishing process was first extinguished. At the same time, the total volume of spent water was 1.6 liters. This is significantly less than the volume of water spent in the practice of extinguishing fires with the use of aviation - 3-5 l / m ² . Therefore, the application of the proposed method allows to increase the area of fire extinguishing at least 2-3 times in comparison with the widely used extinguishing methods, which use local discharge of large water masses.

The use of only one spray nozzle type ФЭ512-4-3 during extinguishing showed a significantly longer extinguishing time (260 s).

When extinguishing, for example, a forest fire, several aircraft can be used as fire extinguishing medium delivery devices, each of which is equipped with a spray device that generates droplets of a certain size. At the same time, spraying devices are installed on each subsequent delivery device, generating droplets with radii smaller than on the previous one. When the first device reaches a fire, water is sprayed along its edge, and subsequent delivery devices, moving after the first, spray water into the same area of the fire. If necessary, the whole process is repeated until the fire is completely extinguished.

Claims (3)

1. The method of extinguishing fires, which consists in creating a fire-retardant strip in front of the fire front into which a fire-extinguishing medium is supplied, characterized in that, using several successively moving delivery devices, each of which has its own spray device, a liquid fire-extinguishing medium is supplied in the form of several successively moving sprayed jets, and each subsequent stream consists of droplets with smaller radii than the previous one. 2. The method according to p. 1, characterized in that the plane can be used as a delivery device. 3. The method according to p. 1, characterized in that water can be used as a liquid extinguishing medium.

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