The principle of a flame arrester

A flame arrester and a vent valve are two completely different devices; vent valves are generally used in storage tanks to prevent them from being drawn into a vacuum as well as from experiencing overpressure. A flame arrester is used to prevent open flames from spreading from one system to another. The interior of a flame arrester is typically made of stainless steel mesh, and it operates on the principle of the flame’s extinguishment distance. Simply put, the combustion flame of each combustible substance (gas) has a maximum flame-out distance; when the flame passes through a space with a diameter smaller than this maximum distance, it goes out, thereby preventing the flame from passing through.

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A flame arrester is a safety device used to prevent the spread of flames from flammable gases and liquids and to avoid explosions caused by backflow. It is usually installed in storage tanks and pipelines for transporting or discharging flammable and explosive gases. 1. 1 Heat transfer: One of the necessary conditions for combustion is to reach a certain temperature, namely the ignition point. Below the ignition point, combustion will stop. According to this principle, the spread of flames can be prevented by lowering the temperature of the burning material below its ignition point. When the flame passes through the many small channels of the flame arrestor, it becomes several small flames. When designing the flame-arresting elements inside a flame arrester, it is necessary to maximize the contact area between the small flames and the walls of the channels, thereby enhancing heat transfer and reducing the flame temperature below its ignition point, and so preventing the spread of the flame. 1.2 Wall effect: Combustion and explosion are not direct reactions between molecules; rather, they are triggered by external energy, which breaks molecular bonds and generates activated molecules. These activated molecules then split into free radicals that have a short lifespan but are highly reactive. The free radicals collide with other molecules, producing new substances, while also generating new free radicals that continue to react with other molecules. When the burning combustible gas passes through the narrow channels of the flame arrestor, the probability of collisions between free radicals and the channel walls increases, resulting in a decrease in the number of free radicals participating in the reaction. When the passage of the flame arrester becomes narrow enough, collisions between free radicals and the wall of the passage become dominant. As the number of free radicals decreases sharply, the reaction cannot proceed any further; in other words, the combustion reaction cannot continue to spread through the flame arrester.