Miniaturised ultrasonic-wave velocity and attenuation sensors for liquid

The development of miniaturized ultrasonic-wave velocity and attenuation sensors for liquids is described. The sensors employ ZnO-film/Pyrex-glass composite diaphragm transducers. The transducers efficiently launch spurious-free ultrasonic-waves into liquids over a wide bandwidth in VHF/UHF ranges. Emphasis is placed on the development of sensors used for online monitoring of industrial production processes. The sensor is made by uniting the transducer with an ultrasonic-wave reflector, so that any external mechanical shock and vibration are avoided. Three methods for ultrasonic-wave velocity measurement are attempted. Their performance is discussed. The attenuation constant of ultrasonics in liquids is measured by comparing the amplitudes of multiple-reflected ultrasonic echoes with each other. It is shown that accuracy can be improved by taking the electric characteristics of the transducer into consideration