flame arrester

A flame arrester is a safety device used to prevent the spread of flames from flammable gases and liquids, as well as to avoid explosions caused by backfire. 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 wall of the channels, thereby enhancing heat transfer and reducing the flame temperature below its ignition point, so as to prevent 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, resulting in new products, while simultaneously generating more 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 radicals and the wall of the passage become dominant. As the number of radicals decreases sharply, the reaction cannot proceed any further; in other words, the combustion reaction cannot continue to spread through the flame arrester.

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Principle of the flame arrester: Currently, metal wire mesh filters are commonly used in flame arresters; multiple layers of such metal wire mesh are arranged inside the cylinder. The purpose of this is to absorb heat, as metals are good conductors of heat, thereby preventing one of the three elements necessary for combustion: the heat required for burning. The three elements of combustion are a combustible material, an oxidizing agent, and the heat required for combustion. Due to the absorption of a large amount of heat, even if the first two factors are present, insufficient heat prevents the combustible material from reaching the temperature required for combustion (spontaneous ignition); as a result, the combustion process cannot continue and must come to an end. Simply put, the fire extinguishing principle of a flame arrester is that when a flame passes through a narrow opening, the sudden increase in heat loss due to cooling causes the combustion to stop. The factors affecting the performance of a flame arrester are the thickness of the flame arrestive layer and its pores or channels

Regarding the working principle of flame arresters, there are currently two main views: one is based on heat transfer； The first is based on the wall effect. 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 arrester, it becomes several small flames. When designing the flame arrestor’s internal flame-arresting elements, it is necessary to maximize the contact area between the small flames and the channel walls in order to enhance heat transfer, thereby reducing the flame temperature below its ignition point and 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 free radicals colliding with 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 the radicals and the wall of the passage become dominant. As the number of radicals decreases sharply, the reaction cannot proceed any further; in other words, the combustion reaction cannot continue to spread through the flame arrester. Note: 1. Flame arresters generally come with matching flanges, and the flange standard is HGJ. 2. The main material is carbon steel of grade 20, and the stainless steel is 1Cr18Ni9Ti. 3. The flame arrester can be installed in conjunction with a piping system, or it can be connected directly to valves such as control valves and vent valves. 4. The combustible gas must be a clean gas before entering the flame arrester. 5. During installation, it must be installed in the direction indicated by the flame arrester’s gas flow mark. 6. After the flame arrester has been in use for a period of time (usually about one year, depending on the purity of the gas), it should be cleaned or its flame arrester core should be replaced to prevent impurities from clogging it.