An Optical Fiber Temperature Measurement System Based on the Principle of Spectral Absorption

Abstract

The invention discloses an optical fiber temperature measurement system based on the principle of spectral absorption, which utilizes the Doppler broadening effect of gas spectral absorption when pressure changes to measure the broadening range of spectral absorption lines to realize temperature measurement. The structure is simple and the price is low. The temperature measurement range is only limited by the working temperature range of the optical fiber, which can reach 700 °C; short distance problem. The temperature measuring probe is a fully sealed structure, which prevents the probe from being mixed with the measured medium during high temperature measurement, the internal gas pressure is not affected by the external pressure, and the temperature measurement result is accurate; the pure gas filled will not produce decomposition products, thereby ensuring the measured environment. (eg transformer oil) insulation properties. Both the transmission medium and the probe are non-metallic materials, which can be used in harsh electromagnetic environments or occasions with insulation requirements, such as power transformers, switch cabinet interiors or heating furnaces.

Description

technical field [0001] The invention relates to the technical field of optical fiber temperature measurement, in particular to an optical fiber temperature measurement system based on the principle of spectral absorption. Background technique [0002] At present, the known optical fiber temperature measurement basically has the following two forms: one is to measure the temperature based on the fluorescence characteristics of the temperature-sensitive fluorescent material, such as the afterglow method; the other is to use the fiber Bragg grating (FBG) system to measure the temperature. . Afterglow fluorescence temperature measurement is made by connecting an optical fiber to a fluorescent probe with built-in phosphors. When the phosphors are excited by a certain wavelength of light, they emit fluorescence energy. When the excitation is cancelled, the persistence (time) of the fluorescence afterglow It is related to the ambient temperature, and then the purpose of temperatur...

AI Technical Summary

Problems solved by technology

The afterglow method of fluorescence temperature measurement is connected by an optical fiber and a fluorescent probe with a built-in phosphor. When the phosphor is excited by a certain wavelength of light, it is stimulated to radiate fluorescence energy. When the excitation is cancelled, the persistence (time) of the fluorescence afterglow It is related to the ambient temperature, and then the purpose of temperature measurement is achieved by measuring the fluorescence afterglow time; the fluorescent powder (such as ruby, etc.) used for fluorescent temperature measurement has problems such as expensive phosphor powder (such as ruby, etc.), high hardness, difficult powder production, narrow detection range, and short transmission distance of fluorescent optical fiber.

The Fiber Bragg Grating (FBG) system obtains sensing information through the modulation of the fiber Bragg (Bragg) wavelength by the external temperature. As the pressure increases, the temperature and stress cross-sensitivity characteristics of the sensor itself will affect the temperature measurement accuracy

In addition, the fluorescent powder or thermal conductive agent in the existing optical fiber temperature measurement probe can produce decomposition products when the temperature is too high, which directly affects the insulation performance of the measured environment (such as transformer oil)

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