Water mist system key to success is to increase the surface area per unit volume of water particles. After the fine particles of water, even if the same volume of water, but also can increase the total surface area. And the surface area increases, the more easily heat absorption, cooling the combustion reaction. Absorbing heat of vaporization of water particles easily, the volume increased by about 1700 times. Because the generation of steam, both dilute the concentration of oxygen near the flame, choking the combustion reaction, and effective control of the heat radiation. It is believed that water mist is mainly through high-efficiency cooling and the dual role of hypoxia asphyxia.
Water mist particle diameter size distribution and fire-fighting capability of the relationship is a complex issue. In general, the first one and two water mist extinguishing liquid fuel tanks for fire better, and does not stir the liquid pool. Typically, with the first stage trigger sprayer spray extinguishing Class A combustible material is difficult, it may be that the water mist can not penetrate and wet combustion products carbon layer. However, because the fine mist ejection speed is high, the burning surface or in a closed space, is conducive to reduction of oxygen in the case, or can extinguish Class A combustible material. This shows that, for a given combustion, the particle diameter of water mist fire-fighting capability is not the only factor in the decision. Fire Extinguishing system but also with respect to water mist spraying flame direction, velocity and water density, which are closely related.
Tests showed that a single low-pressure system to produce a greater flow of water particles, in the fight against the fire class A deep, showing good results. This is due to its relatively large flow (single-flow high-pressure system, 3 to 4 times), resulting in a wet surface effect, but reduced the system by blocking the fire extinguishing capabilities. The single-stream pressure fire-extinguishing system is exactly the opposite effect, due to the smaller diameter of the water particles to improve the fight against fire by blocking the ability of the weakened extinguish Class A fires deep effect. Test showed a large space by the blocking of the fire, the fire place when the oxygen concentration to 18%, the flame can be extinguished.
Water mist system with an alkyl halide or other gas extinguishing systems, fire extinguishing time is much longer, the former is about 100-200 seconds, which is around 10-20 seconds. In addition, the size of the enclosed space open water mist effect is small, in an open space, water mist system than the gas fire extinguishing system has obvious advantages.
The size of the fire, water mist fire extinguishing system effects also affect the fierce fires are burning slow burning fire easily extinguished. This is because it quickly consumes the oxygen, and is accompanied by the generation of large amounts of steam and turbulence. hand held sprayer Spray water mist system, while the temperature of the fire a sharp decline, which helps reduce the heat caused by artificial fire and property damage.
About mist electrical insulation, a foreign company has used Securipex Fire-Scope 2000 water mist system been tested, injected into the system with electric motors, generators and power strips inside a closed room, the equipment inside voltage is 220 ~ 440V. The results show that in the release process, the resistance readings decreased significantly, but as usual, the device is operating normally. In the general case, as the device becomes dry, the resistance value will be restored to normal. Can water mist system for electrical equipment, the key lies in the mist particle size. Certain types of water mist systems for electrical equipment should be certified by the relevant departments.
I think that the water mist system can be used to protect valuable factory production equipment, high-rise building immersed power transformers within the chamber, owned diesel generator room and storage room and fuel, gas boiler room. High-pressure water mist system and Shuangliu media can be used for important high-rise building in the high and low voltage power distribution room, it is important electronic communications equipment room, power plant control room, gas turbines and other places.
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