A flow transducer for cold water using ferrofluids

Abstract As water is a limited, vulnerable, and regenerable natural resource, it is necessary that it should be protected and managed economically. Proper management requires, among other things, carrying out measurements in order to control water consumption. Flowmeters with characteristic equations based on the pressure drop are non-linear and the liquid measured is not proportional to the pressure drop. The flow meters most frequently used are those with local hydraulic resistance (Industrial Flow Measurement, Bucharest Technical House, Bucharest, 1988; Mesure des vitesse des fluides, Masson, Paris, New York, Barcelona, Milan, Mexico, San Paulo, 1986). Usually, the local hydraulic resistance for liquid flows can be obtained by decreasing the flowing section, as in the case of Venturi tubes. While Venturi tubes have a high reliability, they have some disadvantages which consist in difficult manufacturing, high price, and difficult replacement with another element for the flow section decrease. These drawbacks may be avoided by manufacturing an induction flow transducer with magnetic liquids for the measurement of the liquid flows. In this context, the article presents for the first time the operating principle and the “flow–voltage” characteristic curve of an inductive ferrofluids flow transducer for water in the case of a turbulent flow regime. The transducer uses the magnetic liquid properties and has no moving parts (components). It can be used in stationary flowing conditions. The device can be adapted to virtually any flow range by using a section pipe and an adequate U-tube manometer.