METHOD AND DEVICE FOR EXTINGUISHING FIRE INSIDE RESERVOIR Russian patent published in 2005 - IPC

FIELD: fire-fighting, particularly to extinguish fires in opened and sealed containers with highly inflammable and combustible liquids with the use of gas-dispersed (gas-aerosol, gas-powder, gas-dust, gas-liquid) mixture.

SUBSTANCE: method for extinguishing fires inside reservoirs involves delivering fire-extinguishing mixture to liquid fire site from device floating in the reservoir, wherein above mixture is formed in the device by supplying gaseous and/or liquefied retarder and/or gaseous and/or liquefied homogenous fire inhibitor under pressure of not less than 1 MPa into vessel containing powder or liquid heterogeneous fire inhibitor and provided with bursting membrane or valve, which discharges gas-dispersed mixture through outlet pipeline and annular nozzle sprayer when pressure exceeds 1 MPa. The mixture is discharged as compact jets having 5-15° divergence angle in plane parallel to liquid plane with flow rate of not less than 10 kg/s and with outflow velocity at nozzle exit section of not less than 70 m/s. Jets are sprayed through 360° to prevent crossing thereof inside reservoir in radial direction so that vacuum is created in formed fire-extinguishing mixture discontinuity which results in sucking combustion products from upper fire area to vacuum area. This creates continuous all-around fire-extinguishing zone. Ratio between fire-extinguishing areas defined by gas-dispersed jets and combustion products is from 1:1 to 10:10. Mass ratio between gas and dispersed phases of fire-extinguishing mixture is from 0.2:1 to 15:1. Liquefied retarder is carbon dioxide and/or nitrogen and/or argon or mixture thereof. Gaseous and/or liquefied homogenous fire inhibitor is halohydrocarbon. Heterogeneous fire inhibitor is fire-extinguishing powder composition based on alkali metal and/or alkaline-earth metal and/or ammonium carbonates and/or chlorides and/or phosphates or is fine-fog generating orthophosphoric acid solution. Fire-extinguishing device is adapted to extinguish fires in reservoirs with floating roof or with pontoon and is installed in reservoir roof or pontoon center. Vessel with fire-extinguishing mixture and delivery system may be arranged outside the reservoir and in this case fire-extinguishing mixture is fed through spraying assembly floating in reservoir center and connected with above vessel by flexible pipeline. Device includes vessel with sealed lid and gas source providing injection of fire-extinguishing gas contained in the vessel, shutoff-and-triggering means and outlet pipeline with spraying nozzle arranged in upper reservoir part above liquid level. Gas source(s) is(are) is(are) communicated with vessel

interior filled with dispersed fire-extinguishing powder through siphon pipe or siphon pipe system secured to lid. The lid has outlet pipeline with cross-sectional area equal to 5-20 summary cross-sectional areas of siphon pipes. Installed at lower end of outlet pipeline is membrane or discharge valve opened when vessel overpressure reaches 1 MPa. Upper pipeline end is connected with annular spraying nozzle having at least one row of orifices located in horizontal plane and arranged along a circle. Device has positive buoyancy in liquid with density of not less than 700 kg/m³ to provide distance from reservoir liquid surface to spraying nozzle location in standby state of 0.01-0.05 of reservoir diameter. The device also has self-acting independent shutoff-and-triggering means.

EFFECT: increased fire-extinguishing safety and efficiency, decreased material consumption.

6 cl, 1 dwg