容器壁中超声余振信号的透射衰减特性及其应用

文章对残存于容器壁内的超声波余振信号的衰减特性进行了分析和实验测定，结果表明，由于固液界面中超声波透射性强，所以当容器内部为液态介质时，容器壁中超声余振信号衰减快。而固气界面中超声波的透射性弱，故当容器内部为气态介质时，容器壁中超声余振信号衰减慢。实验表明，两种工况下容器壁中超声余振信号的衰减时间之比可达1：2—1：3。因此，通过检测容器壁中超声余振信号持续时间的大小，即可判定容器内部液位是否达到换能器的安装点。基于这一原理，文章中提出了一种新的超声波非介入式定点液位检测方法及实施方案。

Analysis of attenuation characteristics of residual ultrasonic waves in container wall and its application

Attenuation characteristics of the residual ultrasonic waves inside a container's wall are analyzed and tested in experiments. The results show that the remaining ultrasonic signals attenuate quickly if the content in the container is liquid since ultrasonic penetration through a solid-liquid interface is high. In contrast, if the container contains a gas, the attenuation process is relatively slow as penetration through a solid-gas interface is low. The ratio of the decay speeds in the two different cases can reach 2:1 to 3:1. By measuring the decay speed, whether or not the liquid level has reached the point on the wall at which the sensor is attached can be determined. Based on this principle, a non-invasive method for measuring the fixed-point liquid level is proposed.