Researches On Ultrasonic Detection Of Gas Micro-leakage In Pressure Vessel

In modern industry, small leak is a major form of pressure vessel damage, and isthe main reason for mechanical equipment failure. Therefore, small leakage detectionand location are of great importance related research.This study focuses on small leak detection of pressure vessel. The existingnon-destructive detecting methods have both advantages and disadvantages when beingapplied. This project compared two main non-destructive methods: capacitive sensorbased electrostatic ultrasonic method and piezoelectric ceramic elements based passiveelectrostatic ultrasonic method. And then a novel detecting method is presented whichcombined the advantages of the both methods.This dissertation is organized as follows. Chapter one makes a brief introduction ofthe research situation and backgrounds of small leak detection. Chapter two presents themain detecting theorems, design principles and characteristics of components, and givesthe theory frame for this study. Circuit modules like electrostatic ultrasound probestransducers module, piezoelectric module, acoustic emission module, amplifier moduleare designed in this chapter also.The software design and application realization are then described in chapter three.A/D capture card and LabWindows/C based data acquisition system is designed here.Main works of signal process and results analysis in done in chapter four. Wepresents potential application and conclusions in chapter five and six respectively.