电解质溶液对金属检测系统影响研究

Study on the Influence of Electrolyte Solution on Metal Detection System

在社会生产过程中,金属检测广泛应用于各领域,尤其是食品、药品安全方面。但目前市场上主流金属探测系统都只适用于干燥无自由移动导电离子的环境,电解质溶液环境中的金属检测准确率始终不尽人意,而许多食品、药品都处于电解质溶液中。为了研究电解质溶液对金属检测系统的影响,根据电涡流传感原理,设计一种基于平衡式双线圈的金属检测系统,通过模拟电路解调信号处理方法,将金属造成的磁感应强度变化转换为电信号幅值与相位变化。实验结果表明,平衡式双线圈金属检测系统对于直径0.6mm及以上的金属物质检测准确率达95%以上,但在电解质溶液环境中准确率大大降低。通过对比发现,电解质溶液对于系统的影响与金属导体对于系统的影响十分相似,难以从硬件方面加以区分,提高电解质溶液环境中金属检测准确率需从算法入手。

In the process of social production,metal detection is widely used in various fields,especially in food and drug safety.However,at present,the mainstream metal detection systems in the market are only suitable for the dry environment without free movement of conductive ions.The accuracy of metal detection in the electrolyte environment is unsatisfactory,and many foods and drugs are in the electrolyte solution.In order to study the influence of electrolyte solution on metal detection system,a metal detection system based on balanced double coil is designed according to the principle of eddy current sensing.The change of magnetic induction intensity caused by metal is converted into the change of amplitude and phase of electrical signal by the method of signal processing of analog circuit demodulation.The experimental results show that the accuracy of the balanced double coil metal detection system is more than 95%for metal materials with diameter of 0.6mm and above,but the accuracy is greatly reduced in the electrolyte solution environment.Through comparison,it is found that the influence of electrolyte solution on the system is very similar to that of metal conductor.It is difficult to make distinguishment from hardware.To improve the accuracy of metal detection in electrolyte solution environment,we need to start with algorithms.