电涡流法检测罐头真空度的探头研制和仪器智能化

Non-destructive Detection of Low Vacuum inside Canned Food and Its Sensors

本文比较全面、系统地介绍了一种食品罐头真空度的无损检测方法。在经典电涡流理论的基础上 ,通过对罐盖在大气压差作用下受力变形的分析 ,以罐盖变形量为中间变量 ,在罐内真空度和检测所用的振荡电路频率间建立起联系 ;给出了制作完成的传感器结构图及其标定方法 ,并简要介绍了整台仪器的组成。所介绍的方法适用于对各种密封容器内的真空度检测。

A technique has been successfully developed to non-destructively detect the low vacuum inside the canned food. On the basis of classical eddy current theory, the can-lid deformation, due to pressure differences in- and outside the can, is used as an intermediate variable to evaluate the low vacuum inside the can by correlating the variations in the alternating frequency induced by eddy current with the pressure inside the can. The sensor designed and fabricated as well as its calibration system are also discussed.