Key Technology Research On Dark-field Water Leakage Sensors Based On Flow-controlled Liquid Waveguides

Liquid leakage detection technology is being widely applied in various places with liquid leakage risks,such as underwater equipment,large-scale data processing centers,semiconductor manufacturing workshops,smart homes,libraries,as well as in petroleum and chemical storage,transportation,and water supply networks.Specific liquid leak detection techniques are required for different locations,installation environments,and types of liquids being tested.Currently,there are many studies and applications of liquid leak detection,but addressing the challenges of drip and seepage measurement requires sensors that have rapid response and high trace detection capabilities.Therefore,the design of a sensor with high realtime performance,high spatial resolution,and sensitivity to trace leaks is of great research value.This article is based on the principle of liquid waveguide and fiber side-coupling transmission,and designs a dark field leak sensor for flow-controlled liquid waveguides.Key technologies required for the dark field leak sensor of flow-controlled liquid waveguides are studied.The specific work includes the following aspects:First,to address issues of unstable changes in optical intensity and susceptible to missed and false detections with side-coupling fiber sensors,a flow-controlled package is designed.The background noise is less than 2n W,which improves the signal-to-noise ratio of the sensor and initially suppresses the noise of the light source.When there is liquid leakage,the liquid flows inside the structure.Since the gas inside the structure cannot be completely exhausted,residual gas exists on the surface of the channel,forming a liquid-gas-solid three-layer interface with the liquid inside the channel.The use of the gas-liquid interface inside the package controls the leakage of liquid on the optical path and increases the fiber transmission power,enabling a liquid leakage discrimination of 1.9d B.Second,the relationship between the fiber coupling structure,coupling power,and insertion loss in the sensor is analyzed.The fiber coupling structure is simulated and analyzed using Zemax software,and a coupling structure is processed and tested on an experimental platform to determine the shape and parameters of the fiber coupling structure,effectively improving the fiber side-coupling power and reducing transmission loss.Third,a Fresnel lens is integrated into the package design to further increase the fiber transmission power,improving the utilization efficiency of the light source and increasing the lateral coupling power by 40%.This significantly reduces the difficulty of signal detection,and increases the density of the fiber side-coupling structure from 5cm to 3cm while maintaining the measurement range,effectively improving the spatial resolution of the sensor.Fourth,the sensor is packaged and tested for performance in different installation modes.From liquid leakage to sensor response,the time range is 0.5-0.7s,achieving high real-time performance.The sensor can detect liquids up to a limit of 0.5 ml,enabling the detection of minute amounts of liquid.Finally,the overall sensor is tested,and the data obtained from comparative testing further validates the reliability of the sensor.