Intensity modulation type liquid level sensing detection method based on cascade connection of double coreless optical fibers

Abstract

The invention discloses an intensity modulation type liquid level sensing detection method based on the cascade connection of double coreless optical fibers. The method comprises a step of acquiring asingle-mode optical fiber, a coreless optical fiber I and a coreless optical fiber II and removing coating layers on the surfaces of the single-mode optical fiber and the coreless optical fibers, a step of welding two ends of the single-mode optical fiber I with the coreless optical fiber I and the coreless optical fiber II, a step of acquiring a wide-spectrum light source device and a spectrograph and connecting two ends of the two coreless optical fibers with the wide-spectrum light source device and the spectrograph by using another single-mode optical fiber, a step of arranging the coreless optical fiber I as a liquid level measuring optical fiber in a container, and a step of sequentially adding liquids with different liquid level heights into the container, recording transmission peak intensity values of the spectrograph at different liquid level heights and obtaining a liquid level height to be measured through corresponding data after a corresponding calculation formula is obtained through linear fitting. According to the method, the liquid levels are detected through a sensor with a simple structure and low cost, the accuracy of measurement is high, besides, the good performance of resisting light source optical power fluctuation is achieved, and the anti-interference capacity is high.

Description

technical field [0001] The invention relates to the field of liquid level sensing, in particular to an intensity modulation type liquid level sensing detection method based on double coreless optical fiber cascading. Background technique [0002] In the field of petrochemical industry, optical fiber liquid level sensor has received extensive attention and research because of its good corrosion resistance, high sensitivity, no working current and lightning protection. Optical fiber liquid level sensors can be divided into phase modulation type and intensity modulation type according to the optical signal modulation type. The phase modulation optical fiber liquid level sensor obtains liquid level information by measuring the peak and trough movement of the output spectrum of the sensor. However, the phase demodulation device is complex and expensive, which is not conducive to the large-scale application of the sensor. The biggest advantage of the intensity modulation sensor ...

AI Technical Summary

Problems solved by technology

Among them, point-type and micro-groove discrete liquid level sensors cannot measure continuously, and grooves on the surface of optical fibers will reduce the robustness of the sensors, which limits their applications

Due to the special structure of the coupled sensor, the linearity of the sensor liquid level response value in a small range is low, which is not conducive to its application in accurate measurement, and the influence of environmental temperature changes on the sensor has not been well resolved

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