Dry powder fire extinguishers principle
 Dry powder fire extinguisher filling inside is dry powder extinguishing agent. Powder extinguishing agent is dry and easy flowing fine powder for extinguishing, by having extinguishing efficacy salts and small amounts of additives was dried, pulverized, mixed powder composed of fine solids. Wind extinguishers third condition is eliminated temperature, the flame goes out. Wind extinguishers large stocks of high-speed air blowing the flame, the combustion of the surface temperature drops rapidly when the temperature is below the ignition, combustion stopped. This is the principle of wind fire extinguisher. Wind extinguisher structure is very simple, an electric motor, fan, air hose, battery.
 The principle of foam fire extinguisher
 Al2 (SO4) 3 + 6NaHCO3 == 3Na2SO4 + 2Al (OH) 3 ↓ + 6CO2 ↑

Carbon dioxide fire extinguishers principle
Carbon dioxide has a high density of about 1.5 times that of air. At atmospheric pressure, liquid carbon dioxide is immediately vaporized, generally liquid carbon dioxide to produce 1kg of about 0.5 cubic meters of gas. Thus, when the fire, carbon dioxide gas can be excluded in the combustion air and surrounds the surface of the object, or distributed in relatively confined spaces, reducing the oxygen concentration around the fuel or protective space, suffocation effect and fire. In addition, carbon dioxide discharged from the storage container, will be rapidly vaporized gas into the liquid, to attract some of the heat from the surrounding, play a role in cooling. Carbon dioxide is mainly used for fighting fire extinguisher valuable equipment, archives, instruments, electrical equipment and 600 volts oils beginning of the fire.

Fire extinguishers principle Shimizu
Water extinguishers extinguishing agents water. Water has a low viscosity at room temperature, high thermal stability, large density and high surface tension, is an ancient and natural to use a wide range of fire-extinguishing agent, easy access and storage. It is mainly depending on the cooling and suffocation effects * put out the fire. Because each kilogram of water was heated to room temperature since the boiling point and fully evaporates, absorbing the heat 2593.4KJ. Therefore, it is their ability to absorb the use of sensible and latent heat to cool the fire to play the role of other extinguishing agents can not match. In addition, water is vaporized and vapor formed is an inert gas, and its volume increases about 1,700 times. When fire, water vapor generated by the water vapor will occupy the space of the combustion zone, the oxygen content of the combustion products diluting around impede fresh air into the combustion zone, the oxygen concentration in the combustion zone is greatly reduced, so as to achieve the purpose of extinguishing suffocation. When the water was spray mist of water droplets and droplet formation of the specific surface area will greatly increase and enhance the heat exchange between water and fire, thus reinforcing its role in cooling and suffocation. In addition, some water-soluble combustible, flammable liquid may also function as a dilution effect; using a strong jet mist can generate combustible, flammable liquid emulsifying effect, so that the liquid surface is rapidly cooled, the combustible vapor generation rate decline achieve the purpose of fire fighting.