Flow sensor for field measurement of viscous liquid usage for consumer studies

摘要

The usage of household liquids such as detergent or shampoo is a relevant parameter in customer research. It has to be measured in a real environment to eliminate effects of staged studies. We present a 3D-printed sensor usable for both flow and derived mass measurements for such high viscous liquids. It can handle pulsating flows and has negligible influence on typical user's behavior. The sensor is a variable-area sensor with a spring-loaded float to ensure operation in all positions. Displacement is measured by a hall sensor and magnet inside the float. Because of the temperature dependence of the liquid's viscosity, a temperature sensor and a look-up-table are employed to derive mass measures from displacement measures. System size is Φ20 mm × 120 mm; it fits in a commercially available detergent bottle. Readout is realized by an IrDA-interface, a LiPo battery ensures six month operation. The sensor exhibits an overall accuracy of -0.36 % and a lower precision of 10.09 % for a nominal range of 1 to 6 g of fluid.