基于超声阻抗和回波声压的外感式液位测量方法

基于容器中液位上下方气液介质的超声阻抗的不同,会引起入射超声波束在容器内壁处的反射和透射特性产生差异,可以利用这个差异,从容器的外部来检测液位。首先分析圆形活塞式探头在金属容器壁内的声场分布特征,在此基础上建立了回波声压的计算模型,最后通过选取一系列不同壁厚的容器和不同直径的探头进行了实验验证,检测结果能够很好地符合理论分析,测量精度能满足检测要求。

A method of liquid level measurement outside of a container based on ultrasonic impedance and echo sound pressure

Due to the different ultrasonic impedance of the liquid and gas media in a sealed container, the reflection and the transmission of a beam of ultrasound will be significant different at the inner surface of the wall of a container, which can be used to determining the liquid level from the outside of a sealed container. Firstly, by analyzing the sound field of a round piston transducer in a metal container wall, a mode of echoes sound pressure calculation was established. Secondly, the proposed method was evaluated through a series experiments, in which two transducers with different diameters and a container with different wall thickness were used. The experiments indicate that the result matches the theoretical analysis and the accuracy meets a detection requirement.