The Method Of Medicine Bags Leak Detection In Real-time And Non-destructive Testing

Real-time and non-destructive leak detection as the start point of studying bags tigntness, and become the primary problem of medicine bag leak. This paper introduced a method which is used to detect whether the medicine bag is leak with real-time and non-destructive. First of all,in order to reduce interference of interfering signal and improve the precision of detecting whether the packaging bag is leak, the acquisition circuit designed by this paper includes signal conditioning amplifier circuit and filter circuit; Secondly,in the process of audio vibration signal, the audio vibration signal was dealed with frame and window. then accumulating the signal which is maed by FFT in the frequency domain to amplificate characteristic signals and filter out interfering signals; Finally,the audio vibration source be played in front of the bag, then audio vibration signals data be collected in sensor of the back of the bag. Secondly, the data was send to a computer by USB and processed by FFT or other methods. Finally, the difference hava been found between medicine bag leaks and airtight. Experimental results show that this method can be applied to the test in real-time and non-destructive.The main contents are as follows:(1)In the first chapter,this paper introduces the research background,purpose and meaning,and makes the analysis and comparison of the bag leak detection program at home and abroad,then summarizes and analyzes the present nondestructive testing methods of soft packing sealing,and gives each scenario for the occasion. At the same time determine the detection scheme of this paper on the basis of experiments; Besides,describes the details of the leak detection principle of this article.(2) In the second chapter,this paper describes the theoretical basis of medicine bags leak, including the propagation of audio vibration signal, and audio vibration signal applications in medicine bag leak detection. After several experiments,this paper gives finally a transmission audio leak detection program.In the end,leak detection principle was introduced.(3) In the third chapter,this paper designed the experimental device,which includes the choose of hardware circuit chip,preamplifer circuit design and band-pass filter circuit design.what’more,based on sampling theorem and microcontroller timing registers, this paper sets 44.1kHz sampling frequency.Finally,this article introduces the structure and principles of the buzzer, then makes parallel audio sensors and audio vibration source as well as USB-based PC.Finally, the audio vibration signal processing algorithm and the FFT-based fast Fourier transform algorithm microcontroller was designed.(4) The fourth chapter is the data analysis and results.This paper focuses on the analysis of the parallel audio at the bottom of the sensor materials, the shape and size of buzzer and the weight of audio vibration source,which make impaction to medicine bag leak detection effect.Finally experimental results verify the feasibility of this scheme.