Intrinsic safety type

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Intrinsic safety type is short for intrinsically safe type. Intrinsic safety refers to a classification of explosion-proof electrical equipment that is manufactured in accordance with the GB3836.1-2000 standard and is designed for use in coal mines. Explosion-proof electrical equipment is divided into categories such as flameproof type, increased safety type, and intrinsic safety type. The characteristic of intrinsically safe electrical equipment is that all of its circuits are intrinsically safe circuits; that is, the electric sparks and thermal effects generated under normal operating conditions or specified fault conditions cannot ignite the specified explosive mixtures. In other words, such electrical appliances do not rely on an explosion-proof casing or filling material for protection; rather, the energy of electric sparks or thermal effects generated by their circuits during normal operation or in case of faults is less than 0.28 mJ, which corresponds to the minimum ignition energy at a gas concentration of 8.5% – the most explosive concentration. 　　Intrinsic safety refers to achieving a safe, reliable, and harmonious integration of all elements such as people, materials, systems, and regulations within a company’s production processes, thereby keeping various hazard factors under control and gradually moving toward intrinsic and permanent safety goals. 　　Intrinsic safety is the means of cherishing life; it focuses on systematic questioning and continuous improvement. It emphasizes using the system as a platform to penetrate through complex phenomena in order to identify the fundamental factors that affect the achievement of safety goals, to pinpoint the key element that can have an impact on the entire system. By ensuring unwavering commitment in thinking, seamless management, no hidden risks in equipment, and no disruptions in the system, it is possible to achieve zero defects in quality and zero accidents in terms of safety. 　　The intrinsic safety of humans holds a prerequisite, guiding, and fundamental role compared to the intrinsic safety of objects, systems, and institutions. 　　The intrinsic safety of human beings encompasses two fundamental meanings. First, humans inherently have a need for safety. Secondly, through educational guidance and institutional constraints, people can ensure accident-free safe production in both the system as a whole and at individual job positions. 　　The inherent safety of humans is a goal that can be continuously approached, and it is also a process composed of specific smaller goals. Human intrinsic safety is both a goal within a process and a process composed of multiple goals. 　　Employees who are intrinsically safe can be simply described as those who want to be safe, know how to be safe, and are capable of being safe. That is, production managers and workers who possess an independent safety mindset and adequate safety skills, and who are able to achieve safe outcomes under the support of a reliable safety environment system. 　　An intrinsically safe enterprise refers to one that is able to ensure long-term safe production in environments with potential safety hazards, relying on internal systems and organizational structures. Based on research into accident causation theories, this model establishes a scientific, systematic, proactive, forward-looking, and comprehensive safety engineering system for accident prevention. 　　The intrinsically safe explosion-proof method is an explosion-proof technique that utilizes safety barrier technology to limit the electrical energy supplied to field instruments within a safe range where neither sparks sufficient to cause an explosion nor a temperature rise on the instrument surface sufficient to trigger an explosion can occur, thereby eliminating potential sources of ignition. 　　For instrument detection and control circuits, limiting energy first means limiting voltage and current. Also, since capacitors and inductors can store and release electrical energy, they must also be limited. 　　In practice, people use spark test devices to experimentally determine the electrical energy limit parameters for gases of different hazard categories. The common energy detonation curves specified in international standards and Chinese standards include voltage-current detonation curves, voltage-capacitance detonation curves, and current-inductance detonation curves, among others. Based on these curves, and with reference to a safety factor of 1.5, it is possible to determine the electrical energy limitation parameters for a given circuit when dealing with a certain type of gas. 　　For example, when dealing with IIC-class gases such as hydrogen, the voltage limit for circuits powered by 24VDC standards (such as gas transmitters, electrical converters, solenoid valves, etc.) is usually set at 28V. By referring to the voltage-current detonation curve at this voltage limit value and taking into account a safety factor of 1.5, the current limiting value at this point can be determined; it should be 119 mA. By referring to the voltage-capacitance detonation curve based on the 28V voltage limit and considering a safety factor of 1.5, it can be determined that the capacitance value in the circuit should be limited to 0.13μF. Based on the 119mA current limit and taking a 1.5 times safety factor into account, by referring to the current-inductance detonation curve, it can be determined that the inductance value of the circuit should be limited to 2.55mH. 　　To limit the surface temperature of the instrument, in addition to restricting the open-circuit voltage and short-circuit current of the circuit, it is also necessary to limit the maximum power of the circuit. 　　An intrinsically safe explosion-proof circuit always consists of an intrinsically safe field instrument and a safety barrier that serves as the device for limiting the energy in the circuit