Low Flow Rate Measurement and Leak Detection for Health Monitoring of Water Equipment

This paper presents recent research into low-cost flow meter designs to measure dripping leaks for health monitoring of water equipment. Water handling equipment is pervasive in our society, to the point it is often overlooked; including plumbing, faucets, bathtubs, showers, toilets, water heaters, water softeners, filtration systems, dish washers, washing machines, etc. Monitoring of the health and usage of water equipment will be a major contribution to the internet of things, providing information about equipment's need for maintenance or re-placement to both conserve water and prevent costly flood damage. Detection of leaks and flow rates are core to monitoring the condition of water equipment. However, commercially available flow meters capable of measuring flow on the order of a dripping leak are too expensive for mass deployment in consumer products (>$300). This paper presents parametric studies of low cost in-line flow meter designs, intended to measure extreme low flow rates (<50 ml/min on the order of a dripping leak in 1/2 inch pipe). Designs were created based on a hybrid of traditional orifice and target meters. Part counts were kept minimal and synthesis methods were kept simple with the goal of minimizing cost. Parametric studies were performed to evaluate the effects of geometric dimensions on the sensitivity, pressure drop, and other traits of the flow meters. Testing was performed both with custom equipment and in the Badger Meter Flow Lab at the Global Water Center in Milwaukee Wisconsin. Results were compared to electromagnetic and mass-based measurements.