Research On The Key Technology Of Optical Fiber Fluorescent Thermometer

The optical fiber fluorescent thermometer is a kind of temperature measuring equipment based on the photoluminescence of the fluorescent material.Compared with the traditional thermocouple measurement method,it has the advantages of anti electromagnetic interference,anticorrosion capability,resistance to high temperature and resistance to high pressure and so on.It can realize the real time detection of temperature in a more harsh environment,and has a broad application prospect.The thesis firstly introduces the development status of optical fiber fluorescence temperature measurement technology at home and abroad.And describes the unique advantages than other temperature measurement technology with optical fiber fluorescence temperature measurement and the purpose of this study.By introducing the working mechanism of the fiber optic fluorescence thermometer,the key factors affecting the temperature measurement are analyzed,and a theoretical foundation for the design of the fiber fluorescence thermometer is established.Then the optical fiber fluorescence thermometer is designed,including light path,circuit,software,structure and algorithm.In order to verify the feasibility of the overall scheme,this designs a comparative experiment of temperature measurement,and the whole scheme is analyzed by actual data.Finally,the design contents are summarized and prospected,and the direction and train of thought for further improvement are put forward.Based on the actual project,the key technologies of the fiber fluorescence thermometer have been deeply studied and discussed in this paper.The following key technologies have been studied:(1)The key technologies of the optical machine structure include: by using single fiber and transmission source signal and the fluorescence signal,reduces the volume and loss of fluorescence fiber optic fluorescence thermometer;selection of excitation light and fluorescence with multiple filters;sealing of optical fiber fluorescence probe by high temperature melting technology.(2)Key techniques for demodulation circuits include: by using the rectangular wave signal and the voltage signal input dynamic adjustment to achieve periodic switch and light output power adjustment,realize the indirect sampling signal amplitude adjustment;differential amplification circuit and differential correction signal are used to amplify and bias the sampling signal;simplify the circuit components,integrate control,processing and communication functions into one chip,which is conducive to the miniaturization of the fiber fluorescence thermometer;using the least squares fitting algorithm,and realize the optical signal instead of fluorescence lifetime calculation and temperature conversion by voltage signal;filtering algorithm for fluorescence lifetime results is used to reduce errors and improve output accuracy.In view of the above key technologies,the following innovations are made in the process of prototype making:First,the fluorescent probe of the optical path uses the high temperature melting seal instead of the traditional probe protection scheme such as metal protective cover or heat shrinkable tube to increase the flexibility and sealing effect of the probe;Second,the electrical characteristics of demodulation part of the device to produce some changes with temperature and to decrease the influence of the part of the signal demodulation circuit,to add a dynamic adjustment signal is used to adjust the signal waveform is stable,balanced accuracyThird,data processing part proposes a combination filtering method for data processing,effectively reducing errors and improving the accuracy of output results and error;Fourth,the software part designs various working modes and parameter reading configuration functions to improve the adaptability of the system.