PPE

Feasibility analysis on improvement of mine safety helmet

Coal is one of the most important energy sources in the world. Because most of the coal is deeply buried in the stratum, the mining of coal must be carried out by excavating the mine. Although the degree of mechanization has reached a certain height now, it is still impossible to realize the pure mechanized mining of coal in coal mines, so it must require personnel to go deep into the mine. 1n the complex and dangerous environment of mine, the safety protection equipment of underground personnel is particularly important. The safety protection equipment of underground personnel includes safety helmet, miner’s lamp, self rescuer, etc. among them, safety helmet, as the most important part of human body head protection equipment, is particularly important< The mine environment is very complex, the depth of the mine varies from tens of meters to thousands of meters, and there is a thick rock layer on it. Although there are supports in the mine, it is still difficult to ensure absolute safety, and the roof disaster is also one of the common disasters in the mine. The head is the most critical part of the human body, so in almost every dangerous situation, the protection of the head is necessary the main function of the safety helmet is to protect the head from the impact from the top and to alleviate the impact. 1ts protection principle is to form a certain gap between the cap shell and the top of the head, which will play a certain role in buffering the impact from the top; At the same time, the spherical smooth cap shell can change the direction of the falling objects from above, so as to avoid the impact on the head on the other hand, the underground safety is not only a threat from the top of the head, but also one of the hazards of mine gas. There is a large amount of harmful gas in the underground air, which is mixed with mineral dust. Breathing this kind of air for a long time will do great harm to human body” Silicosis is a common occupational disease among miners, which is caused by the long-term breath of mine gas considering the above two factors, the safety helmet can only protect the head from impact injury, but it can not protect the harmful gas in the mine< (1) respiratory filtration device through the above analysis, it is known that the safety helmet mainly plays the role of protecting the head from injury. But for the common occupational disease – “silicosis” among underground workers, no equipment can prevent the disease. Therefore, referring to the design of gas mask, the function of respiratory filtration can be added to the helmet in the process of coal mining, a large amount of mine dust will be produced. Coupled with the role of mine ventilation, a large amount of mine dust will dissociate in the air, and underground personnel will breathe in this environment for a long time, which is extremely dangerous to form “silicosis”. Silicosis is mainly caused by long-term inhalation of free silica dust, which causes pulmonary interstitial fibrosis and silicosis nodules. 1n severe cases, it can affect lung function, lose labor ability, and even develop into pulmonary heart disease, heart failure and respiratory failure in addition to the mine dust, the harmful gas in the mine also has great harm to human body. These harmful gases include methane, carbon monoxide, carbon dioxide, hydrogen sulfide, sulfur dioxide, ammonia, nitrogen dioxide, etc. Such as long-term inhalation of trace carbon monoxide, people’s emotional state, simple reaction time, digital span, manual dexterity, digital decoding and visual retention will be lower than the normal level. Carbon monoxide, carbon dioxide and other gases are inhaled for a long time, which has a great impact on people’s lungs and is easy to induce lung cancer. Another example is that long-term inhalation of hydrogen sulfide and sulfur dioxide can cause olfactory decline, neurasthenia syndrome and autonomic nerve dysfunction; Long term inhalation of ammonia can induce pulmonary edema, respiratory distress syndrome and respiratory tract irritation; Long term inhalation of nitrogen dioxide is easy to cause tracheitis, bronchitis, laryngitis and other respiratory diseases. All of these threaten the health of underground workers to sum up, the introduction of respiratory filtration device must have two functions: one is to filter mineral dust, the other is to filter harmful gases< (2) the positioning system plays an important role in both management and rescue the existing underground personnel positioning system is based on the modern radio coding communication technology, applying the signaling technology and wireless transmitting and receiving technology of modern radio communication technology, combined with the current popular data communication, data processing and graphic display software technology. The system can timely and accurately reflect the situation of underground personnel and mobile equipment in each area to the ground computer system, so that the management personnel can grasp the total number and distribution of underground personnel and mobile equipment at any time; The system can track the situation of cadres going down the well, the time of each miner entering and leaving the well and the movement track, so as to facilitate the enterprise to carry out more reasonable scheduling and management this positioning system is a microcomputer system, which is composed of wireless data acquisition, display, control, storage, infrared remote control, communication, watchdog, power supply and other main functional circuits. Mainly through the motherboard, communication board, wireless transceiver board and power supply board and other circuit boards to form an organic whole. The main board is the main control circuit; The communication board is used for data communication with the ground central station; The wireless transceiver carries out data communication with the card carried by the external personnel in the substation. 1ts working principle is: the wireless transceiver data board of the system personnel positioning substation sends the low-frequency encrypted data carrier signal outward through the transmitting antenna; The identification card carried by the personnel is activated after entering the working area of the low-frequency transmitting antenna (the identification card does not work when it does not enter the working area of the transmitting antenna), and the encrypted information with the target identification code is transmitted through the high-frequency transmitting module in the card; The receiving antenna receives the carrier signal from the identification card. After receiving and processing by the main board of the substation, the target identification code is extracted and sent to the ground monitoring computer through the long-distance communication line to complete the automatic tracking and positioning management of mine personnel the limitation of this positioning system is that the signal is transmitted by radio, and the penetration of radio is weak. We all have the experience of mobile phone losing signal in the tunnel culvert, because the tunnel culvert blocks the transmission of external signal. 1f the underground radio communication can be smooth, multiple signal transfer stations are needed. Once a signal station fails, the communication will be interrupted. 1n case of an accident, this situation is inevitable. On the other hand, the deeper the mine is and the larger the scale is, the more signal transfer stations are needed and the higher the cost is. Moreover, the underground personnel need to carry identification cards for transmitting and receiving signals, and the failure and loss of identification cards are inevitable< (1) the material and shape of the respiratory filtration device 1. The material of the respiratory filtration device the gas mask worn by firemen is mainly used to filter the smoke and toxic gas in the fire scene, and the mine environment is similar to this environment gas masks mainly use a kind of material called “activated carbon”. Activated carbon is a kind of excellent adsorbent. 1t is made of wood charcoal, bamboo charcoal, various fruit shells and high-quality coal through a series of processes such as crushing, sieving, catalyst activation, rinsing, drying and screening. 1t has the dual characteristics of physical adsorption and chemical adsorption, and can selectively adsorb various substances in gas phase and liquid phase. Although activated carbon is a very small carbon particle, it has a large surface area, and there are finer capillaries in the carbon particle. This kind of capillary has a strong adsorption capacity. Because of the large surface area of carbon particles, it can fully contact with gas impurities. When these gas impurities touch the capillary, they will be absorbed and play a role in purification. For the filtration of mineral dust, activated carbon can play a very good role. At the same time, the chemical adsorption characteristics of activated carbon can also effectively filter harmful gases. Activated carbon has a wide range of material sources and simple processing, which can be described as “high quality and low price”< Although the mine environment is similar to the fire environment, there are far less harmful substances in it. Therefore, the mine protective mask does not need to be as heavy and tight as the gas mask, and can be designed to be light and easy to take off and wear, just like the mask. The respirator filter with the shape of a mask should be light and easy to carry, and can be attached to the safety helmet as an integral part; Or as a removable part, which will be easy to clean and replace the above analysis shows that it is completely feasible to add breathing filter device on the safety helmet< (2) form and technical means of positioning system 1. Form of positioning system the characteristics of existing positioning system have been analyzed above. 1ts huge system and huge hardware support will inevitably bring huge capital investment the most ideal form of positioning system is to install a small transmitting / receiving device (which can contain the personal information of the person) on the safety helmet, and only need a receiving and transmitting device on the ground, that is, it can monitor the situation of underground personnel. Even if there is a mine accident, as long as the device on the safety helmet is not damaged, the signal can be sent out. The signal can include the personal information of the person, the location, the situation of the scene, etc., which is much more convenient for rescue. 1n short, it is to realize the surface underground direct communication. The transmitting / receiving device installed on the safety helmet needs small volume and multi-function, which can be realized at the current technical level, but it may have higher cost< However, it is difficult to realize the direct communication between the ground and underground by the existing technical means. At present, all wireless communications use electromagnetic waves, which can only propagate along a straight line, and it is difficult to penetrate such a thick medium as stratum. Electromagnetic wave has electromagnetic radiation, long-term exposure to this radiation will also have adverse effects on human health in theory, “neutrino” propagation can be chosen. Neutrinos are a kind of basic particles with strong penetration ability. Neutrinos emitted from the sun can easily penetrate the earth. However, neutrinos only participate in very weak weak interactions, and only one of the 10 billion neutrinos will react with matter when passing through the material as thick as the earth’s diameter, so the detection of neutrinos is very difficult. Up to now, neutrinos are still in the primary stage of research, and many mysteries remain unsolved” “Neutrino” is still in the low-level stage of research, but it has a very broad application prospect, which points out a research direction for the future development of communication technology from the perspective of feasibility, the most ideal positioning device needs further development of science and technology< Summary: Although Chinese miners have been well protected, the accident casualty rate of Chinese coal mines still ranks first in the world, which is related to the management system of coal mines on the one hand and the low level of labor equipment on the other. China's coal mines should widely absorb foreign advanced experience

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