Research On High-precision Detection Method Of Liquid Level In Airtight Container

Liquid level is one of the important detection and control parameters in actual industrial production,and its related detection methods are widely used in chemical,food,pharmaceutical and other industries.After continuous development,liquid level measurement technology is divided into contact liquid level measurement and non-contact liquid level measurement.Although the technical solution for direct contact liquid level detection has been very mature,contact liquid level measurement has detectors that are prone to corrosion,The liquid inside the container is prone to leakage,and it is not convenient for daily inspection and maintenance after use,and it has some disadvantages,and it is very likely to pollute part of the drinking liquid,thereby destroying product quality.Realizing the measurement without direct contact with the measured liquid is the future development direction of the current liquid level detection technology.However,the liquid level in a closed container is mostly measured after imaging by imaging systems,etc.There is basically no system or method for measuring the liquid level alone.From the cost point of view,if you only need to take the liquid level in the container.One indicator,there is no need to use a more costly and more functional imaging system for liquid level measurement.Therefore,the study of closed container liquid level detection methods has very important academic research value and industrial practical value.Under the theme of research on high-precision detection methods for liquid level in airtight containers,and in the absence of relevant research,this thesis has carried out the derivation of the principle formulas for liquid level measurement based on FMCW in the airtight container environment,and completed the research and analysis at the same time.On the basis of the electromagnetic wave transmission characteristics of the airtight container,the model establishment and simulation of multiple channels in the airtight container was completed,including multi-channel formula derivation,attenuation constant formula derivation and simulation,and finally realized the modeling and simulation of the airtight container emission wave echo signal Through analysis,the approximate direction of the liquid level measurement method for the closed container is determined to be the method of combining the EMD algorithm and the distance correction algorithm.Finally,in order to suppress the influence of the inevitable multipath effect and improve the measurement accuracy,by comparing the performance of EMD-related algorithms,the CEEMD algorithm is finally selected,and the CEEMD algorithm is improved,and the spectrum aliasing of the EMD algorithm is further improved.The problem is that by analyzing the pros and cons of the representative algorithms for spectrum correction and refinement,the bisection FFT-FT algorithm is finally selected as the distance correction algorithm part,and then the improved CEEMD algorithm and the bisection FFT-FT algorithm are combined to complete the high-precision level At the same time,the actual measured signal data was used to verify the feasibility of the liquid level measurement method.