A Novel Ultrasonic Method for Liquid Level Measurement Based on the Balance of Echo Energy

Abstract

This study presents a novel method for determining the liquid level from the outside of a sealed container, which is based on the balance of echo energy received by two receiving sensors. The proposed method uses one transmitting transducer and two receiving sensors that are encapsulated in a coupling plane and arranged by certain rules. The calculation and comparison of echo energy are grounded on the difference ultrasonic impedance between gas and liquid media. First, by analyzing the propagation and attenuation characteristics of ultrasonic waves in a solid, an acoustic model for calculating the echo energy is established and simulated in MATLAB. Second, the proposed method is evaluated through a series of experiments. The difference and ratio of echo energy received by two receiving sensors are calculated and compared under two different coupling conditions. Two kinds of the sensors that are arranged by different rules are selected for measuring the liquid level, and the measurement are analyzed and discussed in detail. Finally, the experimental results indicate that the proposed method can meet the proposed accuracy requirements and can effectively solve the problems caused by some poor coupling conditions.

Comparison of Two Different Methods Used for Semen Evaluation: Analysis of Semen Samples from 1,055 Men

“…It has been known that volumetric methods of measuring semen volume give errors [13,[18][19][20]] and yet such methods remain in common use. The absence of the shift of laboratories from volumetric to gravimetric methods may be due to the negligible clinical impact of the underestimated volume.…”

“…Zhang et al [20] measured the volumes of 492 semen samples collected from 137 donors by 3 different methods including electronic balance weighing, volumetric cylinder measuring, and combination of 2 methods. With the combined measuring method, semen weight was first obtained by electronic balance weighing, then the semen density determined by volumetric cylinder measuring, and lastly the semen volume figured out by a formula.…”

A Study on the Model of Detecting the Liquid Level of Sealed Containers Based on Kirchhoff Approximation Theory

“…Along the propagating direction of the sound beam, any of the beam cross sections is a circular region; therefore, when a transducer with radius a is used to emit a beam of ultrasonic waves perpendicular to the outer surface of the container wall, at the inner surface, a circle cross section of the beam can be obtained, and its diameter d can be calculated by Equation (2) [4]:$\{\begin{array}{c}\mathrm{normald}=2\mathrm{normala} \left(\mathrm{normalL}\le \mathrm{normalN}\right)\\ \mathrm{normald}=2\left[\mathrm{normala}+\left(\mathrm{normalL}-\mathrm{normalN}\right)\tan \alpha \right] false(\mathrm{normalL}>\mathrm{normalN}false)\end{array}$…”

“…Generally, these methods can be classified into four types by the realization principle [1,2,4]. Each method has its own application conditions and limitations [4].…”

Measuring Liquid-Level Utilizing Wedge Wave

“…The ultrasonic type is the method that detects the liquid-level by elapsed time of ultrasound-utilizing, air-coupled ultrasound [ 15 , 16 ], the immersed-type ultrasonic sensor [ 17 , 18 ], and guided ultrasound [ 19 , 20 , 21 , 22 ]. Those are widely employed in many applications because of their simplicity of use and safety.…”