Air-foam generator

(Figure) The scheme for the "PGV-0.5 m" air-foam generator
(Figure) The scheme for the "PGV-0.5 m" air-foam generator, which is working thanks to the delivery of the air by the ventilator:
  1. - the ventilator;
  2. - the hose for the delivery of the foaming aqueous solution;
  3. - the nozzle;
  4. - the mesh.

AIR-FOAM GENERATOR (EN: air-froth generator, foam generator; DE: Luftschaumgerät; FR: génératrice à mousse; ES: generador de espuma; RU: воздушно-пенный генератор) is the installation for the extinguishing of the fires with the help of the foam; this generator is used at the mining enterprises (including within the underground mine workings).

The foam (air-mechanical) within the air-foam generator is formed as the result of the spraying of the foaming aqueous solution (96-98% of the water, and 2-4% of the foaming agent) onto the mesh (see the Figure), with the simultaneous blowing of the air through this mesh. In case of the delivery of the inert gas (nitrogen) or steam-gas mixture (the products of the combustion of the kerosene) into the manifold of the air-foam generator, they obtain the gas-mechanical foam (the content of the oxygen is at most 15%), which is distinguished by the high cooling, isolating, and localizing properties.

The air-foam generator allows to obtain the foams with the low (10-100), medium (100-300), and high (more than 300) multiplicity (the relative volume of the foam per the unit of the volume of the foaming aqueous solution). For the extinguishing of the underground fires using the foam with the medium and high multiplicity, they use the air-foam generators, which are working with the ventilator for the local airing, namely, the "PGU-2" or "PGU-200", and also the generators, which are powered by the energy of the pressure of the water, and which are working with the ventilator for the local airing, namely, the "PGV-3 m" or "PGV-0.5 m". The generator of the latter type allows to fill, during the time of less than 1 hour, the underground chamber with the volume of 600-700 cubic metres using the air-mechanical foam of the medium multiplicity, and up to 100 metres of the horizontal mine working with the area of the cross-section of 6 square metres using the foam of the high multiplicity. During the extinguishing of the fires on the territory of the mining enterprises, they also use the air-foam generators, which are consuming the energy of the pressure of the water, which is produced by the pump of the firefighting automobile-cistern (the "Vijuga" foam generator with the productivity of up to 1200 cubic metres per minute). For the obtainment of the foam thanks to the depression within the entire underground mine, they use the "PGP-8" foam-generating bulkheads.