FLOW SENSOR BASED ON A PIEZOELECTRIC POLYMER FLOW TUBE

摘要

The present invention is related to a device through which a liquid or gas fluid flows, allowing the measurement of the respective flow. The device of tubular form is conceived in single part, manufactured from a piezoelectric polymer such as PVDF (2), in which one or more electrodes are placed in its interior (3) and one or more electrodes are placed in its exterior (1). When one of the exterior electrodes is excited by electric voltage, whose frequency is placed in the scope of tens or hundreds of megahertz, the area of the pipe that is in contact with it oscillates, producing an ultrasound with the same frequency. There are basically two readout methods of flow sensors based on ultrasounds: the Doppler Effect and the time of transit. In any of these methods, the frequency or phase shifts between the emitted and the received signals are used to calculate the speed of the liquid or gas passing through the pipe. The flow is then calculated by multiplying the speed of the fluid by the area of the section of the pipe.