How would you deal with a sudden “backfire” during gas cutting?

Tempering is one of the most common accidents when acetylene gas cutting gun is used for gas cutting. It is the phenomenon that acetylene gas flame enters into the nozzle of cutting gun and burns in reverse. The characteristic is that the flame suddenly goes out and the cutting gun emits a rapid “hiss” sound. In the process of cutting with acetylene gas cutting gun, if improper operation, it is likely to backfire accident, light damage equipment tools, serious explosion may occur, threatening the operator’s life safety. It is difficult to find out the exact cause of the accident because of the concealment of the accident caused by tempering. One, cutting gun backfire formation reasons The main reasons for acetylene cutting gun temper are as follows: 1. Cutting tip is too close to heating point If the cutting nozzle is used to remove slag, the pressure near the cutting nozzle will increase, so that the mixed gas is difficult to flow out, and the jet speed will be slow. 2. The cutting nozzle is overheated, and the mixed gas is heated and expands, such as the temperature of the cutting nozzle exceeds 400℃. Part of the mixed gas has no time to flow out of the nozzle, so it burns inside the cutting nozzle and makes an explosion sound of “pop”. 3. The cutting nozzle is blocked by metal splash melting material, and the gas channel in the gun is blocked by solid carbon particles, so that the mixture is difficult to flow out of the heart, and the cutting gun burns and explodes. 4. If the acetylene pressure is too small, the air supply pressure will decrease, the hose will be compressed, bent or damaged, and the oxygen pressure will be too large, and the oxygen will easily enter the acetylene system. At the moment of flaying, the oxygen or air will often enter the acetylene tube of the cutting gun, causing an explosion. 5. The cutting gun valve is not tight or its internal structure is damaged, resulting in oxygen back to acetylene pipeline, forming combustible mixture of gas, which will occur when ignition backfire explosion, this situation is the most dangerous. Ii. Handling of abnormal situations 1. General temper treatment When the cutting gun tempering, should immediately close the acetylene valve, and then close the preheating oxygen valve, as far as possible to shorten the operation time, consistent action. If skilled, you can complete the operation simultaneously. If the acetylene valve is closed too slowly, the tempering combustion in the cutting gun may cross the valve into the gas hose, and even extend to the acetylene distributor and other cutting guns connected with the distributor; If the oxygen valve is closed too slowly, the carbon in the cutting gun will continue to burn with oxygen until the barrel is damaged by red heat, or the backfire spreads to the oxygen hose, causing the inner wall of the oxygen hose to burn in an oxygen-rich state and cause an explosion. After the tempering is extinguished, put the cutting gun into water for cooling or open the oxygen valve to blow the soot in the cutting gun after the tube body is not hot, find out the reason for tempering and solve it before ignition and use. 2. Serious temper treatment If any of the following abnormalities occur, the operation must be stopped immediately, and simple handling is not allowed. (1) The cutting gun seriously backfires, and the cutting gun hose explodes. (2) the ignition is not normal, and there is no airflow or gas but can not be lit after the combustible gas valve is opened (it may be oxygen string into the gas pipeline). (3) In the process of using the cutting gun, the gas flame becomes smaller or goes out, but check the state of the cutting gun and hose is normal (no rolling, kinking, cracking and other phenomena). (4) The cutting gun hose is set on fire. (5) Other abnormal situations that cannot be accurately determined and disposed of. In case of any of the above circumstances, it shall report to the relevant administrative department for disposal in time. If serious tempering occurs or continuous ignition causes multiple tempering, the ignition and explosion will impact the tempering preventer on the acetylene pipe, resulting in its failure, and the overall safety of the system is reduced; If oxygen is mixed into the acetylene main, ignition can cause the entire network to explode. The gas supply department should analyze and check the gas pipe network according to the specific abnormal situation and take corresponding countermeasures. In the use of acetylene cutting gun, it is difficult to completely determine the occurrence of tempering, but as long as operators understand the cause of the occurrence of tempering, develop good working habits, strictly comply with the corresponding operating procedures, take appropriate disposal methods in abnormal situations, the occurrence and the risk of tempering can be greatly reduced.铜焊丝,Copper Welding Rods,铝焊丝,aluminium welding wire,镍焊条,Nickel electrode,药皮焊条,Flux Coated Brazing Welding Rods