Optical fiber temperature measurement system based on spectral absorption principle

Abstract

The invention discloses an optical fiber temperature measurement system based on a spectral absorption principle, which is used for measuring the broadening amplitude of a spectral absorption line by utilizing the Doppler broadening effect of gas spectral absorption during pressure change so as to realize temperature measurement. The structure is simple, the price is low, and the temperature measuring range is only limited by the optical fiber working temperature range and can reach 700 DEG C; the optical fiber is a single-mode optical fiber, the distance between the temperature measuring probe and the host can reach 50 km or above, and the problem that an existing fluorescence temperature measuring optical fiber is short in transmission distance is solved. The temperature measuring probe is of a full-sealed structure, impurities are prevented from being mixed into a measured medium when the probe is heated during high-temperature measurement, the internal gas pressure is not affected by external pressure, and the temperature measuring result is accurate; and the filled pure gas does not generate decomposers, so that the insulating property of the tested environment (such as transformer oil) is ensured. The transmission medium and the probe are both made of non-metal materials, and can be used in occasions with severe electromagnetic environment or insulation requirements, such as power transformers, switch cabinets 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 temperature based on the fluorescence characteristics of temperature-sensitive fluorescent materials, such as the afterglow method of fluorescence temperature measurement; the other is to use fiber Bragg grating (FBG) system to measure . 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 temperatu...

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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