Research on Oxygen Supply System of Coal Mine Refuge Chamber Based on Personnel location and Programmable Logic Controller

Experimental Study of the Gas Leakage and Optimized Supply of Oxygen in Coal Mine Refuge Chamber

Effects of different artificial oxygen-supply systems on migrants’ physical and psychological reactions in high-altitude tunnel construction

WE report an oxygen supply tank failure at our institution that occurred during the morning of a busy operating room schedule when medical center oxygen use was maximal.

Pressure characteristics and dynamic response of coal mine refuge chamber with underground gas explosion

Problems of low temperature, low pressure, low oxygen, and high carbon dioxide (CO2) concentration in the air-conditioning (AC) trains of the Qinghai-Tibet railway can affect the health and comfort of passengers and cause altitude sickness. When the Qinghai-Tibet railway train runs in high-altitude areas, it is necessary to supply oxygen and introduce fresh air to meet the limited oxygen (O2) and CO2 partial pressures (PPs) in the carriage. In this study, a numerical analysis of the correlation between the CO2 PP and O2 PP in AC trains and the air supply parameters (ASPs), fresh air volume (FAV), and oxygen supply volume (OSV) along the Qinghai-Tibet line in summer was conducted. The results show that the influence of the FAV on the energy consumption of the air-conditioning system (ACS) in different running areas is inconsistent, whereas the influence of the oxygen supply system (OSS) on energy consumption is significant. During the oxygen supply period, the FAV had the opposite effect on energy consumption of ACS and OSS. The energy consumption of the OSS was approximately five times that of the ACS. By studying the correlation between the internal environment and ASP of trains running in different regions, the operation modes of ACS and OSS can be reasonably set, which can effectively reduce energy consumption by 20–50%.

At present, indoor diffusion oxygen supply is gradually promoted in plateau area. In order to achieve the normal oxygen concentration needed by human body more effectively, the intelligent control terminal of diffusion oxygen supply system is particularly important to control the oxygen flow rate. Based on the basic environmental characteristics of Lhasa city, in plateau area, this paper constructed the mathematical model of the oxygen supply mode of the intelligent control terminal to the distributed oxygen supply system, and also analyzed and calculated the oxygen supply efficiency and energy consumption under different oxygen supply modes, so as to provide necessary reference for the determination of the plateau indoor oxygen supply scheme and the design of the oxygen supply system.

A gas and coal dust explosion is potential hazard in majority coal mines. A coal mine mobile refuge chamber is a new class of device for miners those who are unable to escape after an accident which can provide basic survival conditions. In this paper, in order to study the propagation law of an underground methane/air mixture explosive wave, and check the failure mode of a coal mine mobile refuge chamber, a full-sized underground tunnel model and a refuge chamber model have been established in ANSYS/LS-DYNA (LSTC, R7.0.0, Livermore, CA, USA, 2014). The simulation results show that the reflected wave pressure on the front surface of the refuge chamber was about twice as high than the incident wave. The pressure on various locations of the chamber was also analyzed. When the peak pressure of the explosive shockwave reached 0.64 MPa, the maximum displacement and stress occur at the center of the front door and the joint of stiffeners and the front plate, respectively. Most parts of the coal mine mobile refuge chamber were in a plastic failure state and the refuge chamber could be defined as damaged. The front door, the front plate, the connecting flange, and the stiffeners on each side were the primary key components. In the end, suggestions were proposed for the refuge chamber.

As one form of the energy resources, coal is becoming more and more important. Due to the particularity in coal mine production, mine accidents some time occur in countries all over the world, which result in large casualties and economic losses. As equipment that can provides the miners with an emergency shelter when the coal mine accidents occur, the underground coal mine refuge chamber is paid more and more attention by coal mine enterprises, and the application of the refuge chamber is increasingly widespread. The general functions, the classification, and the successful applications of the underground coal mine refuge chamber are illustrated first, and the research significance on the underground coal mine refuge chamber is stated. Following, the development status quo at home and abroad for the refuge chamber is introduced. Then, the implementation methods for the key functions of the underground coal mine refuge chamber are demonstrated. Finally, the prospect for the development of the underground coal mine refuge chamber is stated.

To investigate the dispersion process of the underground toxic gas carbon monoxide (CO) into the refuge chamber during a mine disaster and enhance the survival rate of trapped miners, a simplified model of an underground refuge chamber and the main roadway was constructed. The impact of temperature and pressurized air volume on CO dispersion into the refuge chamber has been examined through both analog experiments and numerical simulations, and the reliability of the simulation results was verified. The results indicate that CO dispersion into the refuge chamber through the top of the protective isolation door occurs when the temperature in the refuge chamber is lower than that of the toxic gas. When the temperature of the toxic gas is higher, it tends to enter the refuge chamber through the bottom of the protective isolation door. The evolution of CO concentration in the transition chamber can be divided toxic survival chamber can be categorized into a sudden decline stage and a stable stage. And a flexible isolation door designed to control the entry of toxic gases into the refuge chamber was implemented, and its impact on CO dispersion has been compared and analyzed. When the temperature of the main roadway is 50 °C and the temperature of the refuge chamber is 20 °C, the required pressurized air volume to maintain the CO concentration within the safe threshold (24 ppm) is reduced to 69.6% of that needed without the isolation door, thereby significantly reducing the infiltration of harmful gases from the main roadway into the refuge chamber.

Air distribution of oxygen supply through guardrail slot diffusers in high-altitude hypoxic areas

Wearable oxygen masks play an important role in many fields such as traffic, aviation, medical and health, which is a device worn on the human head. An oxygen supply system (OSS) with a wearable mask is even more essential in aeronautical medicine to ensure the safety of pilots. Because of the complexity of the flight environment, having good control performance for pressure regulation is the key to realize the adaptability of oxygen supply equipment. Based on the application of wearable oxygen mask, an OSS with wearable mask is introduced. A mathematical model of OSS with a voice coil motor drive valve is provided. The improved active disturbance rejection control (ADRC) strategy with feed-forward and two limits is applied to the system according to the dead-zone characteristics of this OSS. The platform is built and mathematical simulations are carried out for the control strategy, comparing with the proportional integral derivative (PID) control algorithm with feed-forward. The results demonstrate that the differential pressure between the mask and the outside can be within ideal boundaries through both improved ADRC and improved PID. And the improved ADRC has better control effect. Meanwhile it can be resistant to disturbances and the changing breathing frequency.

Second wave of COVID-19 pandemic and the surge of mucormycosis: Lessons learnt and future preparedness: Indian Society of Anaesthesiologists (ISA National) Advisory and Position Statement.

The 2006 Sago, Darby, and Aracoma mine disasters in the United States (US) forced the US government to implement the 2006 MINER Act and additional regulations that require all US underground coal mines to install and maintain refuge chambers to manage entrapment emergencies, in particular, fires and explosions. However, there is a debate on whether barricading in refuge chambers is a good strategy to survive such emergencies. Australian coal mines are not required to use refuge chambers and, instead, have adopted a strategy that focuses on instructing and training miners to self-escape to the surface. This paper analyzes merits and problems of using refuge chambers and self-escape to the surface to manage emergencies in fires or explosions in an underground coal mine. The authors found that the use of refuge chambers may not be the best strategy during extensive fires or when multiple explosions happen. In these situations, mine rescuers are unlikely able to extract miners who are sheltered in chambers and conversely, self-escape may save more lives than sheltering. Chances for successful self-escape are further improved by regular, externally assessed training such as Level 1 Emergency Exercises required in the Australian State of Queensland. These exercises put pressure on mine operators to ensure and maintain the effectiveness of their emergency management system.

Purification Characteristic Research of Carbon Dioxide in Mine Refuge Chamber

Oxygen supply is the primary factor in ensuring human survival in confined spaces. Compared with high pressure oxygen bottles, potassium superoxide oxygen board has advantages such as small size, large oxygen storage per unit volume, absorbing carbon dioxide while providing oxygen. However, the release rate of chemical oxygen in a confined space relates to the concentration of carbon dioxide, temperature, humidity and other environmental parameters. To meet human survival needs within the refuge chamber, this paper made experiments on potassium superoxide oxygen production performance factors, including humidity test, carbon dioxide concentrations test, surface spray wet test and so on. Through tests the amount and the rate of oxygen production, and the removal efficiency of carbon dioxide of potassium superoxide in different situations are obtained. And through a human survival experiment, the potassium superoxide oxygen board can satisfy the human body needs is validated. These all provide basis for the establishment of auxiliary oxygen supply facility in the refuge chamber.