Vacuum and Helium Leak Testing Techniques Used for Very Large Size Vacuum Chambers

Abstract

AbstractOver the last few decades, mass spectrometric helium leak detection method (MSLD) has emerged as the ultimate and superior non-destructive leak testing technique useful for vacuum as well as pressure vessels. Very high sensitivities of leak detection (10–10 to 10–6 Pa m3/s) and very short response time for the technique (milliseconds to a few minutes) have been achieved even in very large vessels of volume larger than 10 m3. This work describes the techniques used for determining the vacuum tightness and integrated helium leak rates of very large size vacuum chambers. Simple and direct leak detection techniques are found to have many limitations in large vacuum vessels due to poor sensitivity of detection and very large response time. In this work, typical problems that arise in the helium leak detection of very large volume vessels (volume >10 m3) and the methods deployed to improve the sensitivity of detection which helps to find out the location of defects and quantitatively ascertain the leak rate are described.KeywordsNDT leak testingMSLDVacuum systems