Clamp-on ultrasonic transducers with improved dynamics for flow measuring applications

In this paper the research results are presented related to clamp-on metallic transducer design aspects for the ultrasonic flow metering application of gaseous or liquid mediums with low density in the range of 50 kHz ...500 kHz. When the wavelength becomes comparable with the sizes of the wedge there is a large risk to obtain a long ringing due to multiple reflections of the acoustic waves inside of the transducer. Hereby it has been reached limitation of the influence of the diffraction effects and spurious echoes on obtaining signal by using the clamp-on transducers with metallic and plastic lamellate wedges and selecting thickness and material of wedge plates. Impulse response approach was used for simulation. Experiments and simulations showed that the best dynamics may be reached if to use laminated wedge with thin metal plates of 1-3 mm fabricated from the copper alloys.