Ultrasonic Sensors for Measurements of Liquid Level, Volume and Volumetric Flow in a Tank

This paper proposes an application of industrial interest to assess the capacity of a tank, to measure and to control the contained liquid level and flow by using ultrasonic sensors. A tank is generally characterized by a cylindrical lateral surface which may be generated by rotating a curve around a fixed axis. The rotation of an ultrasonic sensor permits to fit out the generating curve of the surface so that the tank volume may be evaluated. The reconstruction may be then used to measure the quantity of water contained in the tank by means of a second ultrasonic sensor placed above the mouth of the tank and able to give the water level out. Both the ultrasonic sensors have been carefully located for avoiding possible unexpected reflections. Finally, the authors realize an experimental set-up for automatically controlling the water volume by a mechatronics system in which they make use of an electro-valve and an electro-pump. As the water level may be obtained while filling or emptying the tank and the time may be considered in each measurement, the volumetric flow may be estimated. Experimental tests will be shown and technical details will be discussed.