Back-Pressurizing Leak Detection of Airtight Container with Large Volume

We addressed the back-pressurizing leak detection of airtight container with a large volume up to 1.17×10⁴ cm³. The influence of the leak detection conditions, including the adsorption/desorption of residue gases on inside/outside surfaces, and pressure and holding time of pre-injected helium, on the leakage-rate was theoretically analyzed and experimentally measured with the lab-built test platform. The results show that at a predicted leakagerate in the order of 10^-6Pa·m³/s, the back-pressurizing leak detection works pretty well. When it comes to the lowest detectable leakage-rate at a predicted leakage-rate below 10^-6 Pa·m³/s, especially below 10^-7 Pa·m³/s, the back-pressurizing leak detection outperformed the conventional one with helium mass spectrometer. The problem of large error remains to be solved to more accurately predict the background leakage-rate of the large-sized container with a leakage-rate below 10^-7 Pa·m³/s.