1 Eliminate the method of accumulating gas in blind lanes 1.1 When the air duct joint is disconnected outside the blind lane, when the gas is exhausted, the air duct joint is disconnected in the fresh air flow of the full wind pressure supply air outside the blind alley, and the gap size of the joint surface of the air duct is changed, and the feeding is adjusted. The air volume of the blind lanes is used to achieve the purpose of restraining the accumulation of gas in the roadway. During the process of discharging gas, as the two air duct joints are gradually disengaged from each other until the joint is completed, the air volume sent to the blind lane is also small to large, until the local air blower discharges the entire air volume. Finally, the power supply and air supply can be restored when the inspection confirms that it is safe and reliable. 1.2 Use the three-way adjustment method reserved by the air duct to connect a short section of three ventilators between the fan outlet and the air duct. When the tunnel is normally ventilated, the branch air duct of the three ventilators is tied with a rope, and at this time, the entire air volume of the fan is sent to the heading face. When it is necessary to exclude the gas accumulated in the roadway, open the branch air duct of the tee and tie the main air duct with the rope. The degree of the bale is determined according to the gas concentration accumulated in the roadway: part of the air volume is still sent to the heading face, and the other part is The air volume enters the blind alley, diluting and discharging the gas accumulated in the blind alley. 1.3 Opening the damper adjustment method near the local ventilator The local ventilator is installed in the intake tunnel of the mining area, and the return air directly enters the return airway of the mining area. There is a damper for traffic and pedestrians in the communication lane between the two lanes. When the tunnel is normally ventilated, the damper is completely closed. When the gas accumulated in the communication lane needs to be discharged, the air volume is adjusted by the opening state of the damper (half or full opening), and the gas in the communication lane is diluted to make it at the air return. Not exceeding the limit. 1.4 Dilution cylinder adjustment method The dilution cylinder is a three-ventilation cylinder welded with steel plates. There are two sets of valves and control handles on it. The dilution drum is installed in the full-air pressure ventilation tunnel outside the roadway of the roadway. The gas detector is used to measure the concentration of the discharged and diluted gas, and the opening degree of the dilution cylinder valve is controlled and adjusted according to the concentration. 1.5 Self-controlled gas drainage device The self-control gas drainage device is mainly composed of a control host, a dilution cylinder and a hydraulic pump station. The control host and the hydraulic pump station are all installed near the fan in the air inlet lane, and the dilution cylinder is installed in the 10~15m position of the single headway. Both ends are connected by a flexible air duct, and the hydraulic pump station and the dilution cylinder are used. High pressure hose connection. Install three methane sensors in the vicinity of the dilution cylinder, 10 to 15 m below the downwind side of the tunnel, and near the fan. Gas-discharging principle: The methane sensor in the above system transmits the detected gas concentration signal to the control host. After the host judges, the three-position four-way solenoid valve is commanded to be turned on or left. After the oil circuit is turned on, the cylinder is made. The piston expands and contracts, drives the adjustment door of the dilution drum to rotate, and distributes the air volume according to the degree of opening and closing of the regulating damper. Part of the air is sent to the excavation working face to discharge high concentration gas, and the other part is discharged from the damper of the dilution cylinder to the roadway, diluting the discharged high concentration gas, so that it is evenly mixed and not over-limit, achieving the purpose of automatically and safely discharging gas. 2 Method for discharging gas accumulated in closed roadway The roadway that has been stopped for a long time has built a closed wall at its entrance, and there are more gas accumulated inside. Fans and ducts must be installed before gas is removed. The gas discharged from such roadways is excluded, and the sectional discharge method is adopted. 2.1 Check whether the gas outside the closed wall is over-limit. If it exceeds the limit, start the blower to dilute and dilute; if it is not over-limit, open two holes in the corner of the closed wall, and then turn on the fan to blow. At the beginning, the air cylinder should not be blown to the closed wall, and the wind direction should be controlled according to the concentration of the blown gas. 2.2 After the airtight removal, the inspectors and other staff members enter the roadway to check the gas, and then extend the air duct to remove the gas. When the gas concentration near the exit of the air duct in the roadway falls below the limit, the air duct mouth can be narrowed to increase the wind flow range, and the high-concentration gas in front is blown out; when the gas concentration is lowered, a short-segment air duct is connected, the same Increase the airflow range to remove the gas in front; remove the short air duct and connect the long air duct to continue to discharge the accumulated gas in front until it is dug into the working surface. 3 The treatment of gas accumulation in the roof of the roof When a roof collapses on the roadway or the working face, and the top of the road is open (high), high concentration of gas is often accumulated due to poor ventilation at the top. There are two general treatment methods for accumulating gas at this location. 3.1 Filling the open space method Filling the open space method is to first put the wood or Jingjing on the shed where the height is raised, then fill the empty space with the loess, or mix the polyurethane with a grouting pump and then inject it into the air. Inside the crucible, the foam expands and fills the air. In this way, the space in which gas accumulates can be eliminated, and the gas accumulation is saved. Usually, it is used when the roof area is not large. 3.2 Wind flow blowing method 1 Wind flow blowing method to deal with accumulated gas is a commonly used measure. Under the condition that the height is less than 2m, the volume is less than 6m3, and the wind speed of the roadway is more than 0.5m/s, the wind barrier air guiding method can be adopted, and the material of the wind barrier can be made of wood board, canvas or air duct cloth. 2 In the place where the height is more than 2m, the volume is more than 6m3, the wind speed of the roadway is lower than 0.5m/s, and the local fan is used for air supply, the branch air duct is used to guide the wind. The air duct is sent to the top of the roof by a fan to blow up the accumulated gas. 4 Prevention and treatment of gas accumulation at the corner of working face The most fundamental measure to prevent the accumulation of gas in the corners of the working face is to rationally select the ventilation system. The W-type, Y-type, and U+L ventilation systems are good at preventing and dealing with gas accumulation in the upper corner. 4.1 Guided airflow dilution to take away the essence of airflow dilution is to introduce fresh airflow into the upper corner of the mining face, and dilute and carry away the accumulated gas. 1 Wind barrier method: This method is adopted when the gas area accumulated in the corner of the working face is not large and the concentration is not high (less than 3%). 2 tail lane method: used for places where gas emission is large and the limit is severe. Two lanes are arranged in the return air of the working face: one is the return air duct with the highest allowable concentration of 1.0%, and the other is the special return air tail lane with the gas concentration up to 2.5%. Part of the wind flow enters the return air lane from the front of the work surface, and the other part of the wind flow enters the tail lane from the rear of the work surface without passing through the upper corner. 4.2 Pumping the upper corner gas adopts the exhaust fan or the mobile gas pumping station, and uses the ventilation negative pressure to lead the upper corner gas, and introduce the gas into the iron air cylinder or the flexible air cylinder. The air duct is directly laid to the return air duct. The safe location uses the pressure difference across the air duct to continuously discharge the upper corner gas. 5 Other treatment methods for accumulating gas 5.1 Treatment of gas layered accumulation near the roof The so-called gas layer means that the gas is suspended near the roof of the roadway and forms a relatively stable belt-like accumulation, which can be formed in different forms of support and any section. The main methods to prevent and eliminate the gas layer are: increase the wind speed in the roadway; increase the wind speed near the roof of the roadway; treat the accumulated gas with a swirling air cylinder; and close the isolated gas source. 5.2 Gas accumulated near the coal mining machine to deal with the mining face, gas accumulation is likely to occur near the shearer cutting and between the body and the coal wall. Usually, the gas automatic detection alarm power-off device is installed on the shearer, and once the gas exceeds the limit, the power is cut off and the coal cutting is stopped. Increase the air volume at the working surface and increase the wind speed near the machine and the coal mining machine to eliminate local gas accumulation. When the wind speed of the working face cannot meet the prevention of gas accumulation near the shearer, the method of increasing the wind speed at the local location should be adopted, and the wind speed of the shearer attachment is usually increased by a small ejector. Parts For Cars And Home Appliances Parts For Cars And Home Appliances ,Shock Absorber Boot Covers,Small Steel Ball Bearings,Elevator Non-Standardized Component Ningbo Metal Sharing Supply Chain Management Co., Ltd , https://www.zenlesf.com
Safety treatment method for coal mine gas accumulation
Before the gas emission, all the roadways through which the gas flows and the mining face and the diverticulum where the gas outlet is cut off by the exhaust gas flow must be cut off, the personnel must be evacuated, and a special person should be set to guard. Roof fall cave, Working Face corner, near the coal mining machine, near the tunnel roof and low wind speed sites that discharge gas, are easy to accumulate gas. The main measures to prevent gas accumulation are to strengthen mine ventilation management, and to deal with over-limit and accumulated gas, summed up, mainly including dilution, exclusion and isolation.