Most fire extinguishers are composed of solid materials with numerous tiny channels or pores, as this facilitates gas flow and allows for minimal requirements of these channels or voids—small enough to extinguish flames. The mechanism behind flame extinction involves heat transfer and wall effect.

Thermal Conductivity

Due to the fire arrester's composition of numerous tiny channels and gaps, when flames enter these narrow passages, they create numerous small flame streams. At this point, the heat transfer area of the channels is substantial, allowing the flames to exchange heat through the channel walls, thereby reducing their temperature. Once the temperature drops to a certain level, the flames naturally extinguish. Experimental data shows that when the thermal conductivity of the fire arrester material is increased by a factor of 460, the diameter of flame extinction only changes by 216%. This primarily indicates that the material is secondary. In other words, while heat transfer is a contributing factor to flame extinction, it is not the primary cause.

2. Wall Effect

Combustion and explosion are not direct reactions between molecules, but rather triggered by external energy, which breaks molecular bonds, creating activated molecules. These activated molecules then split into short-lived but highly reactive free radicals. These free radicals collide with other molecules, forming new products and generating additional free radicals that continue to react with other molecules. When flammable gases during combustion pass through the narrow channels of a flame arrester, the likelihood of free radicals colliding with the channel walls increases, reducing the number of free radicals participating in the reaction. When the channel of the flame arrester becomes sufficiently narrow, collisions between free radicals and the channel walls become predominant. Due to the急剧 decrease in the number of free radicals, the reaction cannot continue, meaning the combustion process cannot propagate through the flame arrester.