The Research And Design Of Optical Fiber Liquid Level Sensor

With the rapid development of society and industry,there has been a further improvement of the sensor technology in both accuracy and working environment.In this thesis,specific to the demand of liquid level measurement with high-precision and intrinsically safe,the following two types of optical fiber sensor probes are studied,and an optical fiber liquid level sensor system is designed.Firstly,based on the principle of coupling loss between optical fibers,a single-transmission sensor probe is designed.In the preparation process of the probe,in order to ensure the coupling of light between two transmission optical fibers,a plastic diaphragm fixing device is designed to ensure the alignment degree of the cores of the two transmission optical fibers,at the same time,the affecting factors of the sensor probe are analyzed and the theoretical force analysis of the probe is carried out in this thesis.Secondly,specific to the problem that the single-transmission sensor probe cannot eliminate source fluctuation well,an enhanced optical fiber sensor probe structure has been proposed and studied in this thesis.Through the theoretical modeling and analysis to the sensor probe,the design of the probe structure can effectively eliminate the influence of the instability of the light source,improving the measurement performance of the sensor.Finally,specific to the optical fiber liquid level sensor system,an overall design of the system is carried out in this thesis,and the experimental performance test is carried out on the two sensor probes,meanwhile the experimental data is compared and analyzed.The experimental results show that the developed single-transmission sensor probe and enhanced sensor probe are feasible in liquid level measuring.Among them,the single-transmission sensor probe with a stainless steel diaphragm diameter of 1.8cm,a thickness of 0.02 mm,and a distance of 5mm between the transmission optical fibers shows good measurement performance.