Patent ID: 8205507

Claim:
An ultrasonic sensor for measuring local flow rates in liquid melts, said sensor consisting of a low-dispersion ultrasonic waveguide, in which the material thickness of the structure carrying the ultrasonic waves is less than the minimum wavelength of the ultrasonic signal to be transmitted, transversely with respect to the transmission direction, a piezoelectric transducer and an electrical signal matching circuit, the low-dispersion ultrasonic waveguide which is connected to the piezoelectric transducer being composed of a material which has low acoustic attenuation with an acoustic attenuation coefficient of α<10 dB/m in a temperature range above 200° C., which is relevant to the application, and is chemically resistant to the melt, and that end face of the low-dispersion ultrasonic waveguide which faces the melt being closed and being able to be wetted by the melt.