| 摘要 |
An ultrasonic method for determining liquid level in a container employs an electromagnetic acoustic transducer (EMAT) to launch and receive longitudinal ultrasonic waves into a thin metal wall or thin metal foil seal of the container, causing it to vibrate and launch ultrasonic compressional waves into liquid contained therein. The compressional waves travel through the liquid contents and reflect off an interface, returning to the thin metal wall and causing it to vibrate in the presence of the magnetic field produced by the EMAT transducer assembly. This induces a voltage in the eddy current coil of the EMAT transducer assembly, and by measuring a time of flight of the ultrasonic compressional waves through the liquid contents, and by using a preestablished value for a velocity of the ultrasonic compressional waves within the liquid contents, the liquid level of the contents can be determined.
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