Optical fiber grating liquid level sensor and its preparation method

Abstract

The invention discloses an FBG (Fiber Bragg Grating) liquid level sensor and a preparation method thereof. The sensor comprises a metal base, pressure sensing membranes, two metal capillary tubes, optical fibers carved with two FBGs having different wavelengths, pins and a tail fiber sleeve, wherein the optical fibers penetrate into the two metal capillary tubes; an FBG is located in the first metal capillary tube; a sensing FBG is located between the two metal capillary tubes to form a structural unit; the pressure sensing membranes are fixed on the metal base, and an air cavity is formed between the pressure sensing membranes; the structural unit is located in the air cavity; the first metal capillary tube is located at the center of each pressure sensing membrane; the optical fibers are vertical to the plane where the pressure sensing membranes locate; the second tube capillary tube stretches out of the metal base and is positioned by the pins; and the tail fiber sleeve is fixed at the lower end of the metal base to be communicated with atmosphere. The metal capillary tubes are titanium tubes; and the metal base is made of stainless steel. The sensor can be applied to inflammable, explosive and strongly-corrosive liquid, and has the advantages of wide dynamic range, an FS with the precision of 0.5%, a linearity of 99.7%, electromagnetic interference resistance, easy reusability and the like.

Description

technical field [0001] The invention relates to an optical fiber grating liquid level sensor and a preparation method thereof, belonging to the field of sensor technology. Background technique [0002] Liquid level measurement is widely used in various fields of engineering production. The liquid level sensor is a device used to detect liquid height information, and it plays an important role in engineering production. There are many types of current liquid level sensors: [0003] 1 Mechanical float level gauge: The mechanical float level gauge uses a transmission device to convert the information at the same height as the liquid level into a pulse signal or a continuous signal. The converter is some mechanical reed, magnet, electronic or optoelectronic equipment. [0004] 2 Electronic liquid level sensor: The measurement principle of electronic liquid level sensor is to convert the change of liquid level into the change of electrical parameters, and use the measurement ci...

AI Technical Summary

Problems solved by technology

[0010] The purpose of the present invention is to provide a fiber grating liquid level sensor and its preparation method in order to further solve the technical problems of small dynamic range, poor linearity, low precision and cross-sensitivity of the existing fiber grating liquid level sensor

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