关键词: 智能纺织品, 电子织物, 织物结构, 液体传感器, 检测系统

Abstract:  Conductive liquids are generally easy to detect due to their conductivity. However, sensors arranged at a single point can only be effective when a large volume of liquid flows through, often failing to detect micro-leaks in a timely manner. Liquid leak sensing cables extend leak detection from a point to a line, but they still require a substantial amount of liquid to flow through the cable to trigger an alert. Existing smart fabrics further extend leak detection from lines to planes, enabling real-time detection of micro-leaks of conductive liquids as low as a single drop (0.05 mL). Despite this advancement, they cannot provide feedback on the location of the leak. For detecting the location of leaks, there are two primary methods: continuous localization and zonal localization. Although the accuracy of zonal localization is lower than that of continuous localization, in practical use, it is a low-cost and practical solution to first identify the area where the micro-leak is located (usually with meter-level accuracy) and then manually conduct further detection and handling. The main challenge of zonal localization is to achieve more zoning with as few output wires as possible. 
This paper designs a smart fabric for detecting and locating conductive liquid micro-leak. The fabric features 2n conductive warp yarns along its edges, each warp yarn making contact with the densely arranged conductive weft yarns on the fabric. The warp yarns are further interwoven to form n2 detection combinations, corresponding to n2 regions along the warp direction of the fabric. By scanning the on/off status of these detection combinations, the location of the leak can be identified. The number of regions formed by these warp cross-combinations, which is n2, is significantly greater than the 2n-1 regions formed by conventional combinations. In this study, a smart fabric with six conductive warp yarns was prototyped. Slices of the fabric were prepared for structural observation, and a dedicated circuit was set up for electrical testing. A drip test was conducted to verify the localization function, and a specialized detection system was developed for trial use. The slice observations reveal that the double warp structure can achieve both isolation and contact between warp and weft yarns, ensuring electrical insulation and conduction. Testing of the circuit demonstrates the repeatability and reliability of the double warp structure, meeting the needs for constructing numerous detection combinations and supporting large-scale production. Functional verification tests of the fabric's locating detection show that the prototype fabric, using 3+3=6 warp yarns, can achieve zonal localization for 3²=9 zones. When paired with a detection system equipped with automatic selection and conduction identification functions, the fabric can monitor micro-leaks in real time and feedback the location of the leak occurrence.
Due to the square-increasing relationship between the number of zones and half the number of warp yarns, expanding the aforementioned 6 conductive warp yarns can enable the fabric to feedback the exact location of leaks with meter-level accuracy within a range of tens to hundreds of meters. However, the current application range of this fabric is relatively narrow. Future research will focus on integrating it with other materials, such as embedding it into concrete, pipelines, large containers, etc., to expand its usage. 

Key words: smart textile, e-textile, fabric structure, liquid sensor, detection system