Study On The Explosion Protection Of Equipment And Transimission Systems Using Optical Radiation

This article introduces the concept of equipment and transmission system using optical radiation, also the application status and application conditions of equipment and transmission system using optical radiation. By briefly discussing the methods, category and importance of explosion protection technology, introduce the importance of explosion protection research and explosion protection certification for equipment and transmission system using optical radiation.Because there are no relative standards for evaluating equipment and transmission system using optical radiation, this article bases on IEC60079-28 standard, introducing the protection methods and evaluation methods of equipment and transmission system using optical radiation in explosive atmosphere. This article analyzes the advancements of evaluation methods and testing apparatuses used by other countries,and then works out ways and apparatuses which are appropriate for China, which fill the blank of evaluation methods and testing apparatuses for evaluating equipment and transmission system using optical radiation.This article introduces 4 possible ignition mechanisms:a) Optical radiation is absorbed by surfaces or particles, causing them to heat up, and, under certain circumstances, this may allow them to attain a temperature which will ignite a surrounding explosive atmosphere.b) Thermal ignition of a gas volume, where the optical wavelength matches an absorption band of the gas.c) Photochemical ignition due to photo dissociation of oxygen molecules by radiation in the ultraviolet wavelength range. d) Direct laser induced breakdown of the gas at the focus of a strong beam, producing plasma and a shock wave both eventually acting as the ignition source. These processes can be supported by a solid material close to the breakdown point.From the principle of non-electric working and light ignition mechanism, its advantages in explosion protection are discussed. Three evaluation methods and three testing platforms are developed. From three aspects of optical power, optical irradiation and optical pulse power, the three evaluation methods and testing platforms cover all the optical radiation type. Proven by real exercises, the three evaluation methods and testing platforms can evaluate the safe level of equipments and transmission system using optical radiation from explosion protection aspect, providing future standard and certification with theory and equipment supports.