In the event of a fire in the mine, not only will a large amount of equipment and coal resources be burned, but also a loss of production, and a large amount of toxic gas will be generated, which will spread into the underground and cause a large number of miners to die. In mines with gas and coal dust explosion hazards, gas and coal dust explosions may also occur, and the damage is even more serious. The prevention and control of mine fires is very important.
Mine fires are divided into internal fires and external fires. Fires caused by external fire sources, such as lights, matches, smoking, stoves, shots, mechanical friction, electric welding, current short circuits, etc., are caused by fires caused by fires. The fire caused by spontaneous combustion of coal is called internal fire, and the internal fire accounts for about 75% of the total number of mine fires.
The main measure to prevent fires outside the mine is to prevent open flames, electric fires and artillery fires. The measures to prevent open flames are: open fire and smoking are strictly prohibited in the underground; it is strictly forbidden to engage in electric welding and fire welding. If it is necessary to weld, special measures should be made for approval; within 20m near the wellhead and the ventilator, there must be no fireworks or heating with a stove. .
The measures to prevent electric fire are: explosion-proof or intrinsically safe electrical equipment must be used underground, and the performance of the equipment should be good; it is strictly forbidden to use the bulb to heat and use the electric furnace.
The measures to prevent artillery fire are: using safe explosives, it is not allowed to dump the flame-retardant powder in the medicine roll, and it is not allowed to put a cannon or a cannon. It is not allowed to use an open flame or a power line to shoot the gun; the blasthole seal should be filled and water is used. Gun mud; strictly according to the regulations, charging, connecting and shooting.
Measures to prevent fires in mines involve all aspects of coal mine production.
First, reduce the risk of fire and prevent spontaneous combustion of coal.
In terms of mining technology, it is necessary to correctly select the mine development method, coal mining method and mining procedure, rationally arrange the mining area, and do not arbitrarily extract the specified inter-section and interval coal pillars to improve the innate fire prevention capability of mines with natural fire hazard coal seams. .
In terms of ventilation technology, it is necessary to select a reasonable ventilation method, correctly set up facilities to control airflow, adopt equal pressure fire prevention measures, and strengthen ventilation and fire management to reduce air leakage, which plays an important role in preventing coal from spontaneously generating fire.
The second is to grasp the signs of natural fire, timely forecast the fire, and eliminate the natural fire in the "germination" stage.
The third is to deal with all kinds of hidden fires left in the mining production process, such as strengthening the "three roads, maintenance, strengthening the treatment of waste roads, timely filling the coal roadway, timely treatment of high temperature fire points."
In the event of a fire in the underground, the first person to be discovered should directly extinguish the fire as much as possible to control the development of the fire. And immediately report the mine dispatching room to explain the location, nature and scope of the accident. If the on-site personnel are unable to save and the personal safety is threatened, in the case of clearing the fire, the personnel in the disaster area should be evacuated quickly or evacuated to the refuge chamber as soon as possible. If the access is blocked, a temporary refuge chamber should be constructed to save yourself or wait for an ambulance.
Emergency measures and precautions for handling downhole fires are:
(1) After a fire occurs in the underground, the personnel in the disaster area should be rescued first, and then directly treated with water, chemicals, rock powder and sand.
(2) When the direct treatment method fails, the sealing method should be used immediately to seal the fire area so that the air does not enter the fire area. Thus, the open fire in the closed area can be eliminated by insufficient oxygen. There are two methods of sealing: one is to seal the air inlet first, and the first is to return to the air outlet; the other is to close the air inlet and the return air outlet at the same time. However, no matter which method is adopted, it is necessary to make a quick decision based on the actual situation on the spot, without any delay. In mines with gas, it is best to temporarily close the site at a suitable location from the fire source, and then remove all workers, except the rescue team and firefighters, from the mine. In a serious fire in gas, it is necessary to strengthen the gas inspection and calculate the time when the gas gathers to the explosion limit. If conditions permit, an explosion-proof wall should be built quickly. If it is too late, insert the air duct to ventilate the fire area to avoid Gas gathers. The construction method of the explosion-proof wall is: firstly build a 1.5-2 m thick burlap wall with a linen bag filled with sand; then build a scorpion wall at a distance of about 2 meters from the burlap wall, and between the two walls. Filled with hazelnuts or sand; finally, a brick wall of the top trench is built 0.5 meters away from the wall of the dice, grouting between the brick wall and the wall of the dice. The thickness of the explosion-proof wall is 5-6 meters.
In the above method, the top plate must be sturdy, the seal is tight, and the device for measuring the temperature and taking the gas sample is prepared. After sealing, the grouting fire extinguishing measures should be actively used to strengthen the inspection of the airtightness and the analysis of the gas in the fire zone. The airtightness shall not be opened if one of the following conditions occurs: in the fire zone, the oxygen has not fallen below 3%, and there is still the possibility of gas explosion; carbon monoxide is not extinguished, and the fire zone does not have sufficient cooling time.
(3) When the direct fire extinguishing or the closed fire extinguishing is invalid, the water flooding method may be adopted. However, the flooding method is very damaging to the mine equipment, and sometimes it is impossible to resume production. Therefore, the following two conditions should be fully considered when using this method: if the roadway below the fire area can be abandoned, measures can be taken to prevent flooding; the water source is sufficient, when water is injected, the water source Not interrupted.
(4) When directly extinguishing water with water, it must be strictly waterproof and vaporized to explode. This type of explosion is common when water is used to extinguish large amounts of burning coal. In order to prevent such an explosion, when the water is sprayed, the water flow cannot be directly directed to the center of the fire source. Water should be sprayed from the periphery of the fire source to gradually reduce the range of the fire source until it is finally extinguished. This will avoid the generation of explosive gases, as well as prevent excessive generation of water vapor, and retaliate the workers.
(5) In important places in the underground, there should be a very warehouse, and adequate fire-fighting equipment such as hammers, hooks, braces, shovel, nails, canvas (wind barrier), wooden boards, etc., should be prepared for fire fighting or temporary windshield walls. The stored fire-fighting equipment is not allowed to be used for other purposes; the material must be replenished in time to ensure that it is always indispensable. Bricks, stone, cement or other building materials must be in place and the clay used for caulking should be placed in the roadway for timely fire or fire fighting.
(6) There should be a standing fire and smoke prevention door in the underground wind tunnel and the intake tunnel of each person's mining area. In the event of a fire, and if the fire is not effective, the underground personnel should be immediately evacuated, and the fire and smoke doors should be closed to cut off the ventilation flow to prevent the fire and harmful gases from spreading, resulting in serious casualties.
(7) It is necessary to make plans to prevent and extinguish fires so as not to be temporarily panicked and helpless. The plan should include specific measures to prevent and deal with fires, evacuation routes for personnel in the disaster areas, and entry to the disaster area to rescue the offensive routes of the affected personnel. Regardless of the attack and retreat, the general personnel must enter the wind lane. This must be educated and kept in good faith, and must not be negligent.
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