Optical fiber liquid level measurement device and method

Abstract

The invention relates to an optical fiber liquid level measurement device and an optical fiber liquid level measurement method and belongs to the technical field of optics. The invention aims at solving the problems that an existing optical liquid level sensor is complex in manufacturing process, low in measurement accuracy, small in measurement range and unstable in device structure. The optical fiber liquid level measurement device comprises a laser, an optical fiber coupler, a polarization controller, an electrooptical modulator, an erbium-doped optical fiber amplifier, a microwave source, an arbitrary-function generator, a circulator, an optical fiber Bragg grating, an optical isolator, a sensing optical fiber, a self-heating type optical fiber, a photoelectric detector, a data acquisition card and a power meter. The optical fiber liquid level measurement method comprises the following steps: combining a Brillouin optical-time domain analysis technology with the self-heating type optical fiber, wherein the self-heating type optical fiber converts optical energy into heat energy and is pasted with the sensing optical fiber together to realize thermal transmission; and immersing a sensing part into liquid, judging the position where the liquid level is located by virtue of a temperature abrupt change point, thereby realizing centimeter magnitude resolution, meanwhile, measurement range is tens of centimeters, so that high-resolution and high-accuracy liquid level measurement is realized.

Description

technical field [0001] The invention relates to a liquid level measuring device and method, in particular to an optical fiber liquid level measuring device and method, belonging to the field of optical technology. Background technique [0002] Liquid level measurement is widely used in industrial production, oil storage and transportation, and manufacturing industries, and is an important means to ensure the safe operation of equipment. At present, liquid level sensors based on mechanical and electrical technologies have been widely used, and their reliability has been proven in practical applications. However, such sensors cannot meet the requirements for liquid level measurement in harsh (conductive, explosive or corrosive) environments. Require. As an optical sensing device, fiber optic sensor can solve the above problems, and has the characteristics of anti-electromagnetic interference, high corrosion resistance and high sensitivity. [0003] In the early days, some fi...

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Problems solved by technology

[0003] In the early days, some fiber optic liquid level sensors were proposed, such as fiber Bragg gratings, long-period fiber gratings and tilted fiber Bragg gratings. However, due to their high manufacturing process requirements, complex equipment, and small measurement ranges, their applications are limited.

In recent years, researchers have used the splicing structure of coreless optical fiber and single-mode optical fiber to develop an optical fiber sensor that uses intermode interference to measure liquid level, but its measurement range is not high and the coreless optical fiber is easy to break; in addition, using a small hydrogen Panda-type polarization-maintaining optical fiber etched by hydrofluoric acid, its two ends are respectively fused with single-mode optical fiber, and the liquid level sensor is made by using the principle of Mach-Zehnder interferometer. The length cannot be too long, resulting in a small range of measuring liquid level

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