Gas tightness detector (also known as leak detector, air tightness detector, leak detector, dry detector and leak detector) the traditional test piece tightness (also known as leakage) is the visual bubble method immersed in water or oil. Its equipment is simple and the result is intuitive, but the detection accuracy and efficiency are low, and the influence of human factors is great. It can not realize automatic quantitative leakage detection, and it will also bring moisture and rust to the workpiece, Adverse effects such as impurity immersion and cumbersome post-treatment of water (or oil) on the surface of the test piece, and even some products are not allowed to be tested by this method, such as electronic and electrical components.