Pressure difference-based sensing of leaks in water distribution networks

Abstract

Human society and civilization rely on the constant availability of fresh water. In regions where a local source of potable water is not available, a transportation and distribution pipe system is employed. When these pipes feature cracks, holes, or leaks, the result is a substantial waste of energy and natural resources. As communities grow the loss due to these flaws becomes more costly, and the motivation to detect leaks increases. The purpose of this thesis project is to develop pressure difference-based sensing cells that can be used in an untethered leak-detection device. This device is to be deployed in water distribution networks to locate leaks so that water loss can be minimized. Design of these sensing cells and of the leak-detection device entails evaluating the size and shape of a leak's low pressure region. In this paper, leaks are investigated in this regard and a number of different pressure difference-sensing sensor technologies are explored and evaluated. A silicone-rubber deflecting membrane is selected for the application. The relationship between pressure-derived force acting on its surface and its maximum deflection is evaluated as a means of leak detection. Ultimately, testing reveals that these types of cells are simple and robust. While they deflect as anticipated, the formula used to predict their behavior does not fit the experimental results. It is concluded that this type of pressure difference-sensing membrane is well-suited for application within an untethered sensor, with the opportunity for deeper material selection and more accurate deflection analysis.