The flame arrester consists of a casing, a fire-resistant core and an accessory. The basic principle is quenching. When the flame and hot gas pass through the flame arrester quickly, heat is released outward through the hole wall of the flame arresting element, and the flame and hot gas are sufficiently cooled before completely passing through the flame arrester to achieve fire resistance. Applications include flammable gas delivery systems, flammable gases and liquid storage tanks, etc., installed in pipeline networks that transport flammable gases to prevent gas explosion or detonation flames from propagating along the pipeline under abnormal conditions, but without affecting gas passage. Therefore, the industry expects a high-performance flame arrester that can achieve a small flow resistance and can effectively block fire.

There are a variety arrester classification, according to the metal structure is divided into flame arrester grid, corrugated parallel plate, perforated plate and the like. The typical classification is based on the combustion environment of the combustible premixed gas. There are three categories:

(1) Unconstrained space deflagration process. The flame is burned outside the tank or pipe. At this time, a "pipe end type" flame retardant is used, which is installed at the top of the pipe to serve as a venting atmosphere to prevent the flame from entering the pipe.

(2) Deflagration process in confined spaces. The flame propagates in the pipeline and initially propagates along the pipeline at subsonic speed. At this time, a “line-type” flame retardant is used, which is installed on the pipeline and connected to the pipeline on both sides to prevent the subsonic flame from passing upstream. Into the downstream pipeline.

(3) Detonation process. The flame travels along the pipeline at sonic or even supersonic speeds, accompanied by shock waves, at which point a "line-type" detonation firearm is used to prevent the supersonic flame from passing.

At present, there are two theories that the fire-stopping structure can quench the flame, which is described in detail in the literature. One is the thermal theory, the heat transfer between the flame and the wall reduces the temperature of the medium passing through; one is the theory of chain reaction (wall effect), that is, the flame collides with the free surface on the surface of the structure, and the combustion reaction stops. Prevents the spread of flames. However, the theory of pressure wave suppression for fire retardant structures has not been reported.

The flame coal mine gas explosion at supersonic speeds and more spread, and therefore can be used in coal mines must be the first three kinds of fire retardant structures, metal structures and corrugated structure is one of the representatives.

The metal mesh structure is composed of a single layer or a plurality of metal meshes having a certain number of meshes and apertures, and the fire retarding effect depends on the number of layers and the number of meshes. Generally, the metal mesh of the same mesh number increases as the number of layers increases, but there is a limit. Too many metal meshes or too many layers will increase the resistance of the fluid. Because of its small size, light weight and good quenching performance, multi-layer wire mesh structure has become the most commonly used fire-resisting structure. Many scholars are also committed to the study of the propagation of blast waves in wire mesh structures. Japan's Hojo Hideki, Tsuda Ken and others have systematically studied the quenching performance of the multi-layer wire mesh structure in the pipe. The research found that the critical quenching speed and the wire mesh geometric parameters (volume space rate, mesh mesh, metal) There is a certain relationship between the wire diameter and the like. It is also found that the quenching performance of the wire mesh is independent of its material. The quenching effect of the mesh structure on the flame can also be explained by the two theories of thermal theory and chain reaction theory (wall effect). Wang Zhencheng and Xiaochuan Huifan studied the different flame velocities with suitable metal mesh parameters, and obtained the experimental formula between the critical flame-out velocity and the metal mesh shape parameter coefficient (wire diameter/hole width) and the number of metal mesh layers. It is pointed out that the metal mesh structure not only has flame-retarding properties, but also has a pressure relief effect. On the basis of the predecessors, Yu Jianliang and others studied the influence of multi-layer stainless steel wire mesh structure on the acetylene-air explosion flame and pressure wave propagation in a circular tube with an inner diameter of 81 mm and a length of 1.4-2.9 m. The quenching speed and critical quenching pressure difference are important indexes to measure the quenching performance of a certain anti-explosion structure. The concept of critical quenching and critical quenching pressure difference is proposed for the first time, and the geometric parameters and critical quenching speed of the metal mesh are obtained. An empirical formula for the relationship between critical quenching pressure difference, quenching amount, and maximum overpressure value reduction ratio. This study failed to determine whether the cause of flame quenching is thermal theory or chain reaction theory (wall effect). The empirical formula based on experimental data and some conclusions on flame quenching and pressure wave suppression are based on 40 mesh. And 60 mesh two kinds of stainless steel wire mesh, it is not universal.

The fire-retardant layer of the corrugated flame arrester is composed of a thin corrugated plate made of aluminum , copper , brass, stainless steel, copper- nickel alloy, etc., such as a corrugated thin strip and a thin flat strip wound around the core, A small triangular channel is formed, which constitutes a corrugated flame arrester. As shown in Figure 3, a high-efficiency heat exchanger, when the flame passes through the triangular unit, its front edge and the inner wall of the flame arrester exchange energy, remove heat from the burning gas as quickly as possible, and the gas temperature quickly drops to a safe level. (Below the self-ignition point) to prevent an explosion or fire from occurring in one part of the device from being transmitted to another location. Its use characteristics: large effective section, small flow resistance, large range of detonation and combustion, easy to replace and replace the fire barrier; but high manufacturing technology requirements, high cost; suitable for petroleum storage tanks, oil and gas systems and other gas delivery systems pipeline.

The most promising is the corrugated flame arrester, which is easy to change its structural shape during production to achieve the purpose of effectively quenching the flame, so it can be a good fire-resisting structure before the complete new structure is found. A stainless steel corrugated plate flame arrester disk used for explosion suppression in a furnace/torch system. It is alternately wound by smooth and corrugated steel strips. The tiny gap formed between them is the passage of medium or flame. The gap size in the figure is an important parameter for the standardized production of the fire retardant disc. Once the flame reaches the fire retardant disk, it is cut into countless small pieces. Through the heat conduction between the flame and the steel strip, the flame is cooled and extinguished to achieve the purpose of fire extinguishing. Depending on the distance from the source of the flame arrester to the source of ignition, the so-called pipe length to diameter ratio (L/D), we can choose a detonation-type or detonation-type flame arrester. The detonation-fired flame arrester is suitable for L/D<50, and the detonation-type flame arrester can be installed anywhere in the pipeline, regardless of the L/D value. A temperature detector is usually placed on the flame arrester facing the flame to detect stable combustion that may occur on the flame arrester.

For the study of corrugated structures (triangular holes), as early as 1963, KNPalmer and Tonkin studied the quenching law of propane air deflagration flame through this fire-retardant structure, and gave the flame propagation velocity and triangular aperture (in the unit The relationship between the number of triangular holes in the area and the quenching length is supported by experimental results. In 1972, Rogowski and Ames studied the stationary flame combustion phenomenon on the surface of the corrugated plate flame arrester, that is, the flame resistance test of the flame arrester, and gave the relationship between the temperature rise of the flame retardant surface and the time under a certain gas flow rate. In 1997, Zhou Kaiyuan et al. based on the theoretical research results of the quenching phenomenon of propane-air detonation flame in parallel plate slits, using similar experimental devices to make the fire resistance performance of the newly developed corrugated plate flame arrester in the late 1980s in China. The experimental research and the conclusions obtained from the theoretical model research are derived. The relationship between the flame-retardant core thickness L and the detonation flame velocity of the corrugated plate flame arrester is derived. Formula for calculating the flame arrester parameters of the air mixture deflagration flame.

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