There are many types of mine ventilation systems. According to the structure of the mine ventilation system, it can be divided into unified ventilation and district ventilation; according to the arrangement position of the inlet and return air wells, it can be divided into central type, diagonal type, partition type and mixed type ventilation; according to the working mode of the main fan For push-in, draw-out and mixed ventilation; according to the installation location of the main fan can be divided into underground, surface and underground surface mixed ventilation. The mine ventilation system should be based on the conditions of mine design production capacity, coal seam occurrence conditions, topsoil thickness, well area, ground temperature, mine gas emission, natural tendency of coal seams, etc., in order to ensure mine safety and take into account the production needs of the middle and late stages. Next, it is determined by comparing the technical and economic comparisons of several feasible mine ventilation system schemes. In coal mine safety production, the mine ventilation system is responsible for important ventilation tasks: (1) relying on mechanical ventilation, the quantitative fresh air is continuously input into the well along the established ventilation line to meet the needs of the mining face, the tunneling face, the electromechanical chamber, the powder magazine and other wind locations; (2) Dilute and discharge the toxic, asphyxiating and explosive gases and dusts downhole to meet the requirements of the Coal Mine Safety Regulations, while reducing the heat source and creating a good working environment; (3) Prevent various injuries and explosions, ensure the health and safety of underground personnel, and protect national resources and property. A reasonable mine ventilation system is the key to preventing gas, coal dust and natural fire accidents. Gas is the most serious hazard in coal mines. It prevents gas from exceeding the limit and prevents gas explosion. The basic work is to build a reliable ventilation system, so that the underground roadway and working face can supply wind reliably, and the air volume is sufficient, so that the gas discharge gas content can meet the mine requirements. A large part of the gas for the corners of the coal mining face is caused by air leakage from the goaf to the upper corner of the goaf. Therefore, to control the upper corner gas, firstly reduce the air leakage in the goaf, use the windshield to isolate the ventilation in the goaf, minimize the leakage of the coal mining work to the goaf, and make the high concentration gas in the goaf not flow to The upper corner enters the coal flow face again. This can control the gas emission from the goaf and reduce the gas concentration in the return flow of the coal face. Coal dust has an explosion hazard. One of the purposes of ventilation is to dilute downhole coal dust to a safe concentration and discharge it into the mine. The main factors that determine the effect of ventilation and dust removal are wind speed, direction of wind flow and density of mine dust, particle size, shape, and degree of wetting. When the wind speed is too low, the coarse-grained dust will separate from the air and sink, it will not be discharged and stay in the mining space, increasing the concentration of coal dust; the wind speed is too high, although the dust can be taken away, but the dust in the mining space is blown again. Instead, it will increase the concentration of coal dust. Generally speaking, the optimal dust-discharge wind speed of the driving face is 0.4-0.7m/s, the wind speed of the mechanized coal mining face is 1.5-2.5m/s, and the maximum allowable wind speed of the mining face and the driving coal roadway is 4m/s. . This not only considers the requirements of ventilation on the working face, but also considers the secondary flight of coal dust. For coal seams with natural fire hazard, natural fire prevention should be achieved by selecting a reasonable ventilation system and adopting technical means to control wind flow to reduce air leakage and eliminate natural oxygen supply conditions, so as to prevent and eliminate natural fire. In order to ensure the safety, stability and reliability of the mine ventilation system, a lot of work needs to be done: 1 The ventilation system should have a stable ventilation network structure to ensure the stability of the airflow; 2) Have sufficient ventilation capacity to ensure effective ventilation; 3 Have reliable ventilation facilities And equipment to ensure effective control of wind flow during normal ventilation period and meet the requirements of disaster relief capability; 4 to have a reasonable ventilation network to ensure that the resistance distribution of the roadway can meet the ventilation needs of the various wind locations; 5 establish a sound mine ventilation management system And ventilation management institutions, and staffing; 6 strengthen staff education and training, improve the ventilation management level and technical quality of employees, engineering and technical personnel, and implement total quality management to make mine ventilation safer and more effective. In recent years, China's coal mine technology has developed rapidly, but with the underground mining work, the mine ventilation system will continue to change. Therefore, in the actual production process, the ventilation system must be adjusted, the ventilation network structure should be improved, the performance parameters of the ventilator should be adjusted, and the ventilation system that is complicated and backward and urgently needed to be optimized should be optimized to effectively avoid the occurrence of ventilation accidents. Safety production establishes reliable guarantees. GM PEUGEOT RENAULT VVT SOLENOID Variable valve timing (VVT) solenoid or oil control valve controls the oil flow according to the engine speed and load. VVT solenoid is a vital part of the variable valve timing system. Engine Variable Timing Solenoid Exhaust,Timing Valve Control Solenoid,Vvt Control Solenoid,Variable Valve Lift Solenoid Wenzhou Zhongking Parts Co.,ltd , https://www.oemvvt.com
The Oil Control Valve (OCV) is a a critical part used in every engine that is fitted with variable valve technology (VVT). A single control valve will regulate the supply of oil to a designated VVT hub, to advance or retard the timing by altering the camshaft angle position. Controlled by the ECU, the OCV receives electrical signals, instructing it to adjust the oil flow as required, in accordance to current driving conditions.
Coal mine workers underground production operations, complex natural conditions, poor working conditions. In the process of entering the underground and flowing through the various working places, the ground air will be mixed with toxic and harmful gases and mineral dust, and the composition will gradually change. At the same time, due to geothermal effects, heat dissipation from the human body and machinery, evaporation of water, etc., will significantly increase the temperature and humidity of the downhole air, resulting in poor climatic conditions. To solve these problems, a mine ventilation system is needed. The importance of the ventilation system to the coal mine is as good as the heart. The mine ventilation system is the general arrangement of the arrangement of the inlet and return air wells that supply fresh air to the mines, discharge the dirty air, the working methods of the main fans, the ventilation network and the air flow control facilities. In China's "Safety Regulations for Coal Mines", Articles 100 to 132 regulate the ventilation of mines.