Standard laboratory testing methods of SERTO|
1. Helium leak test
However, there is no such thing as an absolutely tight technical system. Connections always represent a leak risk. That is why engineers are very intent on achieving a high degree of leak-tightness in the development of sealing points and positive fit connections.
We use a helium leak tester to regularly test the leak-tightness of our metal tube unions for current orders and on all new designs, and also if there is a change in material or supplier. The union to be tested is mounted on a tube closed off on one side and is then tested in a vacuum chamber. The test medium is helium, which distributes quickly and evenly in the connection at a pressure of 10 bar.
Why is helium ideal for this test? Because helium has the second smallest atom size after hydrogen and in contrast to hydrogen it is not dangerous, not poisonous and not flammable. High concentrations can be introduced into the test specimen and results are obtained quickly.
If the helium exits through a leak in the union, it is extracted by the vacuum and measured. A so-called “sniffer test” locates the leak. The industry standard for tightness is 10-6 mbar l/s. We guarantee this value for all our metal products. When the individual components are adapted optimally, when the tube processing, mounting and handling is done cleanly and according to our instructions, SERTO unions achieve tightness values of up to 10-9 mbar l/s. This corresponds to a loss of one drop of water in 44 years.