Argon arc welding will produce harmful gas and high frequency electricity in the welding process, so there are several protection and safety measures as follows:
1) tungsten manual argon arc welding currently uses tungsten tungsten with a small amount of radioactive as the electrode. When welding in a closed place or with large current, ventilation and special protective mask should be strengthened.
2) when grinding the end of tungsten pole with grinding wheel due to the need of work, there must be good ventilation because there are radioactive particles in the dust. And the staff should wear masks. It is better to use mechanized closed grinding tungsten pole device.
3) the ultraviolet intensity of argon arc welding is 5 ~ stronger than that of manual arc welding ~ 19 times. In order to prevent intense ultraviolet radiation from harming eyes and skin, wear a mask, white work clothes and gloves when welding, and do not roll up the cuff.
4) in order to reduce the influence of high frequency electricity on human body during welding, the outside of welding cable of welding gun should be shielded by soft metal wire woven hose. One end of the hose is connected to the welding gun, and the other end is grounded without insulation outside. In addition, in order to prevent electric shock, insulation rubber should be added to the ground near the workbench, and the staff should wear insulation rubber shoes.
5) the harmful gases produced by argon arc welding are mainly ozone, NOx and metal dust, so the workplace of argon arc welding should have good natural ventilation and mechanical ventilation devices.
692. What problems should be paid attention to when using liquid oxygen storage tank?
Answer: the difference between liquid oxygen storage tank and gas oxygen storage tank is: with the evaporation of liquid oxygen, the concentration of acetylene in the tank may increase; the natural evaporation of liquid oxygen will increase the pressure in the tank; the temperature of liquid oxygen or gas discharged in the tank is very low. Therefore, during the use and maintenance, strictly abide by the JB6898-1997 "safety rules for the use of low temperature liquid storage and transportation equipment", and pay attention to the following matters:
1) the installation site of the storage tank should be well ventilated. Generally, it should be installed outdoors with fences around. There should be no open fire, combustible and explosive materials or low-lying places within 5 m;
2) the storage tank must have grounding device and lightning protection device to remove static electricity. The anti-static grounding resistance is not more than 10Ω; the maximum impact resistance of the lightning protection device is 30Ω, and it should be tested at least once a year;
3) the filling rate of the storage tank should not be more than 95%, and excessive filling is strictly prohibited;
4) the pressure gauge is forbidden to be oiled and checked regularly; the safety valve must be made of stainless steel or copper, checked regularly and oiled strictly;
5) when the valves, meters, pipelines, etc. on the equipment are frozen, apply 70 ~ Thaw nitrogen, air or hot water at 80℃, and open fire heating is strictly prohibited;
6) when there is liquid in the storage tank, hot repair is forbidden, and repair can only be done after heating to normal temperature;
7) operators must receive professional training and pass the examination before they can take up their posts. Do not wear chemical fiber clothing with greasy dirt or electrostatic effect, and do not wear shoes with nails. Open and close the valve slowly during operation. When stopped, the booster valve should be closed tightly;
8) analyze the acetylene concentration in liquid oxygen regularly (for example, 15 days), and the concentration should be controlled below 0.1 × 10-6, otherwise liquid oxygen should be discharged;
9) during sealed storage of liquid oxygen, there must be someone to monitor the pressure and no overpressure is allowed;
10) liquid oxygen is not allowed to splash on unprotected skin to avoid severe frostbite;
11) when the storage tank has emptied the liquid and cannot be heated immediately, all the valves must be closed immediately. Because the temperature inside the tank is very low, the wet air will intrude into the interior through the connected pipe, causing the accident of freezing and blocking the pipe.
