The Application Of Coal Mine Fire Detection System Based On Distributed Optical Fiber

The fault on coal mine cable line is one of the main reasons for the coal mine fire, and the traditional fire detection only converts the temperature signal c to electrical signal detection directly. In fact, the electrical signal is easily disturbed in the coal mine transmission, which always leads to the low measuring accuracy, low spatial resolution and so on. As the problems of cable line such as its insulation aging skin damage often causes the coal mine fire. The writer uses the distributed optical fiber sensing technology to solve this problem.Compared with the traditional measurement which is called "point" of fire detection, this system uses the optical fiber to achieve the goal of temperature detection. The optical fiber is not only a temperature sensor, but also a signal transmission medium. In addition, in the process of transmission, the light is fully electric insulation, and it also can realize multi-point measurement and position the location where the temperature changes accurately. It has great value for warn the fire.In this paper, it not only analyses the research purpose, significance and the future development trend of distributed optical fiber, but also introduces the principle on the distributed optical fiber temperature measurement. On the whole, the writer sets up a light source module, photoelectric conversion, signal processing and display interface part. Combined with the actual environment of the coal mine. The important components of each module are made with a detailed analysis.In addition, considering the noise in the system, it chooses the most suitable method to reduce the impact of noise. This paper takes great advantage of the cumulative average and wavelet noise reduction algorithm, at the same time, in view of the Rayleigh noise left, this system is optimized, which is based on the traditional temperature demodulation method and it improves the performance of the whole system.At the end of the paper, the writer designs the the PC interface of the system. From which we can see the preset temperature and transformation trend clearly.Once the temperature exceeds temperature that we set in advance, it will start alarm linkage, and remind staff to take measures for preventing the fire.