| 摘要 |
PCT No. PCT/CH92/00065 Sec. 371 Date Dec. 3, 1992 Sec. 102(e) Date Dec. 3, 1992 PCT Filed Apr. 8, 1992 PCT Pub. No. WO92/18835 PCT Pub. Date Oct. 29, 1992.The ultrasonic transmitter (E) is subjected to two different excitation modes, and is mounted on the support (2) which at the same constitutes a waveguide. Excitation of the transmitter at its axial-resonance frequency transmits ultrasonic waves through the liquid to provide a detection signal. Its excitation at its radial-resonance frequency creates ultrasonic waves propagated along the support (2) to provide an operation-control signal. The invention is applicable to the detection of various liquids in a broad range of conditions and is suitable for industrial applications, notably in safety and control systems.
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