A measuring apparatus for optical fiber gas concentration

Abstract

A fibre-optical gas concentration measuring instrument includes broad-band light source (1), optical coupler (4), gas absorbent pool (5), light-sensitive detectors (6, 7) and signal acquiring and processing system (8), it characterized in that a optical isolator (2) is also equipped to tune the fapo-filter (3), the connected relation is as following: the broad-band light source (1) is connected with the input of the optical isolator (2), the output of the optical isolator (2) which is flitted via the fapo-filter (3) is connected with the input end of the optical coupler (4), one output of the optical coupler (4) is connected with the gas absorbent pool (5), the output of the gas absorbent pool (5) and the other output of the optical coupler (4) are connected with the signal acquiring and processing system (8) via the light-sensitive detectors (6, 7). The invention obtains the narrow-band light with the fapo-filter (3), and proceeds difference for two times, has the advantages of simple structure, low cost, safe use and free of interference.

Description

Technical field: [0001] The invention relates to the technical field of optical fiber sensing, in particular to an optical fiber gas concentration measuring instrument which is filtered by a tunable Faper filter and subjected to two differential processes. Background technique: [0002] Gas accidents are one of the main threats to the safe production of coal mines. Continuous, accurate and timely monitoring of the gas content in the mine air is an important guarantee for the safe production of modern coal mines. Therefore, it is of great social and economic significance to develop a safe, reliable and highly sensitive gas sensing system for gas monitoring. [0003] The measurement of gas concentration can be divided into: optical type, thermal catalytic reaction type, thermal conductivity type, semiconductor type, enzyme and biological type, electrochemical direct oxidation type, etc. according to the principle. Optical gas sensors have many advantages that other sensors ca...

AI Technical Summary

Problems solved by technology

In the prior art, using a center wavelength of λ 1 and lambda 2 The filter can obtain signal light and reference light, but this method puts forward higher requirements on the position accuracy and stability of the filter center wavelength

At the same time, λ 1 and lambda 2 Pre-selected, it is not conducive to exclude the absorption interference of other gases at this wavelength; directly use λ 1 and lambda 2 The input and output light intensity of light to calculate the gas concentration is still affected by the unevenness of the light source spectral curve and fluctuations over time

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