We have made ourselves aware with the pressure decay and bubble leak testing methods and other production automation, machine cutting techniques in our last articles. Both the processes are simple, inexpensive and easily automated. However both these methods have significant shortcomings such as the inability to determine the location of leaks and limited sensitivity etc.
A relatively new leak testing technology known as hydrogen leak testing addresses these shortcomings faced in pressure decay and bubble methods. This method actually works as an enhancement to pressure decay systems or as a substitute method. The apparatus and the test procedures for pressure decay and hydrogen leak testing technique are however similar.
This hydrogen leak testing method makes use of a robust, self-calibrating and maintenance-free microelectronic probe that is extremely sensitive and 100% selective to hydrogen. The test gas which is a non-flammable mix of hydrogen and nitrogen is then injected into the test object, and leakage is detected in a variety of ways: In an accumulation chamber where the test object is enclosed, the presence of hydrogen is measured over a certain time interval to determine the total leakage. Alternatively, a hydrogen probe can scan the object’s exterior, either manually or robotically, to pinpoint the location of leaks.
A very useful method, hydrogen leak testing is done on objects rejected by the pressure decay system which are then subsequently tested offline by a separate hydrogen-based leak detection system. Prior to the extensive use of hydrogen method, helium leak testing method was used to address the shortcomings of other leak testing methods. But helium leak testing method proves to be a expensive and moreover the tracing gas helium used in the method is very expensive gas too.
