Analysis and Implementation of Noncontact Level Sensing for a Pressurized Cylinder

Abstract

Fluid level detection for a sealed and pressurized mobile container is very useful for the provider to schedule the delivery of a new one before it runs out of the liquid. This study suggested using the frequencies of tone generated by knocking on the outside surface of the container to detect the liquid level inside. A detailed model based on Euler-Bernoulli beam theory has been proposed to study the feasibility of this method for a cylinder with complicated but practical structure. Household gas cylinders were used to validate the proposed model and the results show that experimental data agree well with the theoretical analysis. The results indicate that the proposed model can accurately explain the behavior of the vibratory frequencies under different liquid levels. An apparatus has been successfully implemented to automatically sense the near empty condition of the gas cylinder.