Research On Acoustic Emission Technique In Large-sized Pressure Vessels Inspection

Now, large-sized pressure vessels are the main manufacturing facilities in chemical fertilizer plants, oil refining plants, chemical factories, medical industries, organic synthesis industries, and they are also special equipments which are apt to cause dangerous explosive and toxic accidents. The main purpose of inspection is to find the dangerous active defects, such as cracks, inadequate penetration, incomplete fusion, and so on.At present, the ways of inspection for in-service pressure vessels are non-destructive testing. Besides the normal non-destructive testing ways,such as RT,UT,MT,PT, the Acoustic Emission (AE) testing based on Kaiser effect and Felicity effect is widely used in pressure vessels inspection, which creats huge economic benefits. After the comprehension on the ways of pressure vessels inspection and the theory of AE technique, In order to find the correct ways of AE testing in large-sized pressure vessels inspection, many trials and reserch have been put on in the selection of AE testing system, AE signal detection and treatment, data display, the procedure of AE testing, adjusting and calibration of AE testing equipments,the procedure of loading operation, noise source and alleviation, and so on.We have done the experiments of AE testing in all kinds of large-sized pressure vessels. The character of AE source signals in pressure vessels and the ways of how to identificate them have been studied and analysed clearly. It provides a good way to decide the safety gradation seperation, when there is no AE source signals. It provides ways to decide the safety gradation seperation by the activity and intensity of AE source signals.According to those results, AE testing has been applied in some large-sized pressure vessels inspection successfully. How to decide the safety gradation separation of pressure vessels by AE testing signals, and draw the conclusion about the ways, the experience,or the rules of AE testing in large-sized pressure vessels inspection, have been researched and concluded. Because of the merits of AE technique, Acoustic Emission technique in large-sized pressure vessels inspection will be widely used and has a bright future, but many problems still need to be extended and further developed.