Thick film flow sensor based on the thermal time-of-flight principle

A new type of a liquid flow sensor is presented which is based on the thermal time-of-flight principle. Device was manufactured in thick film technology on a 96% alumina substrate adopting thermoresistive and piezoelectric inks. The measuring range covers velocity up to 250 mm/s while the reaction time is less then 2 ms. Furthermore, the sensor is relatively insensitive to pollution. The sensor has been integrated into a flow channel with inner dia. of about 12 mm. The sensor presents a resolution of about 0.7 mm/s together with a repeatability better than 1.5% F.S