Testing technology for Hydrogen leak testing

Hydrogen or forming gas leak tests are based on the detection of hydrogen used as test gas. The hydrogen leak test is one of the most sensitive test methods and enables the detection of very low leak rates. As a general rule, a so-called forming gas is used as the test gas, an incombustible mixture of 95% nitrogen and 5% hydrogen. The method allows both integral leak testing and leak detection. The hydrogen leak test is used in test stations and test systems for leak testing and leak detection if a pneumatic test is insufficient with regard to the maximum permissible leak rate, but the high expense of a helium leak test is not required. It enables the detection of very low leak rates up to 5 x 10-7 mbar l / s and is suitable for test items which shall not have any large leaks. Integral leak tests are performed in the production of vehicle air conditioning systems, fuel systems, oil supplies and air suspension systems. In doing so, the test item is filled with forming gas, the test chamber is evacuated, whereby a high vacuum is not required. The gas exiting the test chamber is measured and then the leak rate is determined. In the opposite direction, it is also possible to evacuate the test items, to fill the test chamber with forming gas and to measure gas quantities entering the test items. During leak detection, the test item is filled with forming gas and traversed with a sniffer probe. If hydrogen escapes in increased concentration due to a leakage, it will be detected, evaluated and signaled by the sniffer probe. Examples of applications for leak detection are end-of-line tests of assembled automobile aggregates such as motors or gearboxes. User branches are the automotive supply and automotive industry, the aerospace industry and the medical technology.