The Theoretical And Experimentical Study On Sterilization Effect Of High Voltage Pulse

At present, the traditional sterilization methods can be classified in to three: thephysical sterilization, the chemical sterilization and biological sterilization. Consideringthe defects of these methods, a new sterilization approach taking use of high pressurepulse has been researched in recent years. Sterilization with high pressure pulse is a newtype of heat treatment technology, which produces high voltage in the pulsed electricfield, leading to the microbial cell membrane suffers irreversible electricity perforationand the microorganisms would be sterilized. In this paper, the electric perforationmechanism of cell membrane in pulse electric field is analyzed and a high voltageexponential decay pulse power based on simple Marx circuit is designed. Apart fromthis, the processing cavity with different types is designed to construct the circulatorycooling water system, which is the simulation of sterilization with high voltage in pulseelectric filed. Finally, the static and dynamic sterilization experiments in high voltagepulsed electric field show that the sterilization technique with high voltage in electricfield is an effective way for sterilization in the circulatory cooling water system.The mainly work are as follows:①In according to the present research achievements at home and abroad, theelectric perforation mechanism of cell membrane is analyzed. We calculated theinduced voltage on cell membrane with high pressure pulse, and make good discussionon the influence of membrane and electric parameters for electric perforation efficiency.An improved mathematical model for the actual exponential decay pulse with risingedge is established. The simulation analysis shows that the electric perforationefficiency can be greatly affected by the frequency response and rising parameters ofthe actual exponential decay in electric field.②A high voltage pulse generator with simple exponential decay waveform basedon Marx circuit is developed, which takes use of IGBT switch and single chip system torealize the pulse frequency control. In accordance with the principle of circuit generator,the components parameters are determined through the related calculation.③Combined with the structure of traditional processing cavities, the coaxialcavity and plate cavity are discussed. We developed a parallel plate processing cavitywith simple, adjustable and dismountable structure, which could change the distancebetween the parallel plates in according to different experiment requirements. More suitable processing parameters would be find with the help of pulse power.④A set of sterilization experiments are made, which is simulated to circulatorycooling water system. E.coli is taken as processing object and we detect sterilizationrate by use of flat technology. Through the analysis of the static experiment, we find outthe influences of different electric field intensity, frequency and processing time for thesterilization effect. According to orthogonal experiments, the data of sterilization rateare discussed. Finally we make dynamic experiment by use of plate processing cavity.