Helium is the best choice of tracer gas to find leaks for a number of reasons. It is non-toxic, inert, non-condensable, non-flammable and not normally present in the atmosphere at more than trace amounts (5 ppm). Due to its small atomic size, helium passes easily through leaks. The only molecule smaller than Helium is Hydrogen which is not inert. It is also relatively inexpensive and is available in various size cylinders.
A helium leak detector, also known as a Mass Spectrometer Leak Detector (MSLD), is used to locate and measure the size of leaks into or out of a system or containing device. The tracer gas, helium, is introduced to a test part that is connected to the leak detector. The helium leaking through the test part enters through the system and this partial pressure is measured and the results are displayed on a meter.
Helium Leak Detection Applications
Quality control of production parts and assemblies using helium leak detectors can help assure the integrity of your production process. Typical examples include: hermetically sealed packages, valves, manifolding, seals, vacuum vessels and systems, medical devices, high purity piping, brake lines, fuel lines, hydraulic lines, refrigeration assemblies, radiators, heat exchangers, condensers, storage tanks.