Take a look at these cases of illegal welding and oxygen pressure maintaining accidents

When the refrigeration installer was welding the copper pipe, the oxygen cylinder used for welding exploded suddenly The fragments of oxygen cylinder flew out of the explosion directly embedded in the opposite wall A whole row of toughened glass in the shop was shattered The master who was close to the explosion site was seriously injured, with hearing and vision loss, and was hospitalized But the salesman's thigh was injured by explosion, and after several stitches, he was discharged from the hospital According to the analysis, the cause of the accident is the illegal operation of welding, and the pressure valve is not tightened, the pressure in the oxygen cylinder becomes smaller, so that the blue flame emitted during welding is sucked into the cylinder, causing explosion In addition, according to a platform report, another air-conditioning welding explosion occurred on May 29 There were many pieces of oxygen cylinder and acetylene tank, as well as welding gun and other tools at the explosion site The welding master died on the spot! It is presumed that the oxygen cylinder and acetylene tank did not explode at a safe distance due to improper welding operation during the welding of the copper pipe of the air conditioner In fact, about oxygen welding operation and precautions, the common hidden dangers of welding operation are listed, but the accidents are still frequent Here are the common problems in the welding process, hoping to help you FAQ 1: why should oxygen and acetylene cylinders be stored separately if they are not opened separately? Acetylene is inflammable and oxygen is combustion supporting substance If acetylene leaks and acetylene mixes with air, it will explode violently in case of Mars or open fire The explosion will damage the oxygen cylinder and leak out oxygen In this case, the combustion supporting property of oxygen will make the explosion more violent beyond control So they can't put them together FAQ 2: the acetylene cylinder is placed horizontally Why the acetylene cylinder must be upright when it is not upright? Because the acetylene in the cylinder is dissolved in acetone solvent under pressure Open the valve, reduce the pressure and release the dissolved acetylene into gas Acetylene cylinder placed horizontally may cause acetone to flow out Acetylene dissolved in acetone will volatilize rapidly and mix with air to form explosive mixture Explosion limit: 2.3% - 72.3% (vol) Zui small ignition energy: 0.019mj In case of open fire and heat energy, it will cause combustion and explosion It will not only increase the consumption of acetone, but also reduce the combustion temperature and affect the use At the same time, it will cause the explosion accident of acetylene cylinder due to tempering In addition, the pressure will blow out the solvent and dissolved acetylene, which will lead to the explosion of acetylene pressure So acetylene bottle must be upright! FAQ 3: the cylinder body shall not be exposed to the sun under the hot sun, because the temperature of acetylene cylinder shall not exceed 40 ℃, and the boiling point of acetone shall be 58 ℃ The higher the temperature is, the faster the acetone volatilizes, and the acetylene is separated out, which makes the pressure in the cylinder increase sharply! FAQ 4: the gas in oxygen and acetylene does not leave a few kilograms of pressure in the bottle, so that the pressure in the bottle is greater than the pressure outside the bottle, and other gas can be avoided from flowing in, because the explosion limit of acetylene is very low, a little air is mixed, and it will explode when reaching a certain temperature Therefore, there must be a pressure reducing valve at the exhaust port of acetylene cylinder to prevent air from mixing into the cylinder, or there will be a risk of explosion in the next use With the pressure reducing valve, it is necessary to prevent the air pressure in the cylinder from being less than the air pressure of the external air, and prevent the air from flowing back into the acetylene cylinder The oxygen cylinder shall retain the residual pressure of not less than 0.098-0.196mpa gauge pressure The residual pressure of 49kpa ~ 98kpa in winter and 196kpa in summer shall be reserved for acetylene cylinder In addition, talk about the construction operation taboo! Oxygen pressure maintaining (Forbidden)! As we all know, after the welding of refrigeration equipment, it is necessary to carry out pressure maintaining and air tightness test However, some people use oxygen to maintain pressure in case of nitrogen shortage or lack in order to save labor and convenience How much oxygen pressure has been declared forbidden! Because there will inevitably be oil in the refrigeration system, especially in the compressor, most of the lubricating oil is stored in it, oxygen is forbidden, and it will explode in case of oil! In addition, why the oxygen cylinder, especially the mouth of the cylinder, should not be contaminated or contacted with grease If the oxygen bottle mouth is stained with grease, when the oxygen spews out rapidly, the grease will oxidize rapidly, and the heat generated by the friction between the high-pressure air flow and the bottle mouth will further accelerate the oxidation reaction, so the grease stained on the oxygen bottle or pressure reducing valve will cause combustion or even explosion! Case: two people died and two people were seriously injured when a compressor exploded! The reason is that during leak detection and pressure maintenance, oxygen is injected into the system for leak detection, and then oxygen is discharged after use When there is oxygen in the system, the compressor is started, resulting in compressor explosion.