公开(公告)号：US11268845B2

公开(公告)日：2022-03-08

申请号：US16885804

申请日：2020-05-28

Applicant: NATIONAL APPLIED RESEARCH LABORATORIES

Inventor： Chun-Ming Huang ,  Chen-Chia Chen ,  Chih-Hsing Lin ,  Chien-Ming Wu

IPC: G01F23/296 ,  G01F23/2965

Abstract: A liquid level monitoring system includes: a hardware unit with a tube to extend through a surface of a liquid; a processor unit generating control signals that respectively correspond to target frequencies; a sound generator unit generating, respectively based on the control signals, incident sound waves that transmit in the tube and that are reflected by the surface of the liquid to respectively form reflected sound waves; and a sensor unit for sensing the reflected sound waves to respectively generate feedback signals. The processor unit determines a maximum amplitude frequency based on the feedback signals, and calculates a level of the surface of the liquid based on the maximum amplitude frequency and a length of the tube.