Gas sensor and method for detecting changes in concentration of sulfur dioxide gas

Abstract

The present invention provides a gas sensor and a method for detecting sulfur dioxide gas concentration change by using the gas sensor. According to the gas sensor, an annular cavity comprises a first coupler, a Mach-Zehnder interferometer, a second wave filter and a second coupler, the Mach-Zehnder interferometer comprises two couplers, a sensing arm and a reference arm, the sensing arm comprises a single-mode optical fiber, a hollow optical fiber and a circulator, the fiber core of the hollow optical fiber is filled with sulfur dioxide gas to be detected, the temperature is increased after sulfur dioxide absorbs pumping light so as to cause the optical path f the Mach-Zehnder interferometer be increased, the higher the sulfur dioxide concentration, the larger the optical path change of the sensing arm, and by measuring the ring-down time change of the pulse signal, the sulfur dioxide gas concentration change can be obtained. According to the present invention, by combining the hollow optical fiber optical and thermal technology, the Mach-Zehnder interference technology and the annular cavity ring-down spectroscopy technology, the detection sensitivity of the detected gas is improved, and the influence of the light source fluctuation on the measurement result is reduced.

Description

technical field [0001] The invention relates to the field of gas detection, in particular to a gas sensor and a method for detecting changes in the concentration of sulfur dioxide gas. Background technique [0002] Sulfur dioxide is one of the main decomposition products of the insulating medium sulfur hexafluoride in power distribution equipment. The measurement is usually carried out by the spatial spectral absorption method. In order to improve the sensitivity, a large-volume gas chamber is required, which results in a bulky instrument and makes it difficult to achieve online detection. Contents of the invention [0003] A brief overview of the invention is given below in order to provide a basic understanding of some aspects of the invention. It should be understood that this summary is not an exhaustive overview of the invention. It is not intended to identify key or critical parts of the invention nor to delineate the scope of the invention. Its purpose is merely ...

AI Technical Summary

Problems solved by technology

Usually, the spatial spectral absorption method is used for measurement. In order to improve the sensitivity, a large-volume gas chamber is required, resulting in a bulky instrument and difficult to achieve online detection.

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