Tempering is one of the most likely types of accidents when using an acetylene gas cutting torch for gas cutting operations. It is a phenomenon in which the acetylene gas flame enters the torch nozzle and burns backwards. It is characterized by the sudden extinguishment of the flame and a rapid "hissing" in the torch. Voice.
In the process of cutting with an acetylene gas torch, if the operation is improper, a flashback accident is likely to occur, which may damage the equipment and tools in light, and may explode in serious cases, threatening the life of the operator.
Accidents caused by tempering have great concealment, and it is often difficult to find out the exact cause of the accident.
1. The cutting nozzle is too close to the heating pointFor example, using the cutting nozzle to remove the slag will cause the pressure near the cutting nozzle to increase, making it difficult for the mixed gas to flow out, and the injection speed will slow down.
2. The cutting nozzle is overheated and the mixed gas is heated and expanded. If the temperature of the cutting nozzle exceeds 400 ℃, a part of the mixed gas will burn inside the cutting nozzle before it can flow out of the nozzle, and make a "pop" explosion sound.
3. The cutting nozzle is blocked by metal splashing melt. The gas channel in the gun is blocked by solid carbon particles, which makes it difficult for the mixed gas to flow out of the heart and burn and explode in the cutting gun.
4. When the acetylene pressure is too low, the air supply pressure is reduced, the hose is compressed, bent or damaged and leaks, and the oxygen pressure is too large, and the oxygen easily enters the acetylene system. At the moment of flameout, oxygen or air often enters the acetylene of the torch tube, causing an explosion.
5. The valve of the cutting torch is not tight or its internal structure is damaged, causing oxygen to flow back into the acetylene pipeline, forming a flammable mixed gas, which will cause a flashback and explosion when ignited, which is the most dangerous.
1. Treatment of general tempering
When the torch is tempered, the acetylene valve should be closed immediately, then the preheating oxygen valve should be closed, the operation time should be shortened as much as possible, and the action should be consistent. If skilled, the operations can be done at the same time.
If the acetylene valve closes too slowly, flashback combustion in the torch may pass over the valve into the gas hose, and even extend to the acetylene dispenser and other torches connected to the dispenser;
If the closing speed of the oxygen valve is too slow, the carbon deposits in the cutting gun will continue to burn under the condition of oxygen enrichment until the barrel is burnt red and damaged, or the tempering spreads to the oxygen hose, causing the inner wall of the oxygen hose to be in an oxygen-enriched state. Burned and exploded.
After the tempering is extinguished, put the cutting torch into the water to cool down or after the cutting torch body is not hot, open the oxygen valve to purge the soot in the cutting torch, find out the cause of the tempering and solve it, and then ignite it for use.
2. Treatment of severe tempering
If the following abnormal situations occur, the operation must be stopped immediately, and no simple measures should be taken by yourself.
(1) The torch is severely tempered, and the hose of the torch explodes.
(2) The ignition is abnormal, and there is no air flow or gas but cannot be ignited after the combustible gas valve is opened (it may be that oxygen is strung into the combustible gas pipeline).
(3) During the use of the torch, the gas flame becomes smaller or extinguished, but check that the torch and hose are in normal condition (no rolling, kink, rupture, etc.).
(4) The torch hose was ignited and caught fire.
(5) Other abnormal situations that cannot be accurately judged and disposed of. If the above situation occurs, it should be reported to the relevant management department in time.
If severe tempering occurs or repeated tempering occurs due to continuous ignition, the explosion will impact the tempering preventer on the acetylene gas pipeline, causing its failure and reducing the overall safety of the system;
If oxygen is mixed into the main acetylene pipeline, once it is ignited, the entire pipeline network system will explode. The gas supply department should analyze and inspect the gas pipeline network according to the specific abnormal situation, and take corresponding countermeasures.
In the use of acetylene torches, it is difficult to completely prevent the occurrence of tempering, but the operator only needs to understand the cause of tempering, develop good working habits, strictly abide by the corresponding operating procedures, and take appropriate disposal methods in case of abnormal conditions. The occurrence and danger of fire can be greatly reduced.