Helium sniffing is a leak finding method in which Helium is used as a trace gas in the test object. The instrument can then detect a presence of Helium which has leaked out to the external Environment.
Sniffer leak detection is used to locate leaks in products which can be reworked and tested again. However, the leak detraction method is not quantitative. It is only possible to identify that there is a leak, not the size of the leakage. It is also important to control the Environment so that no Helium is contaminating the surroundings.
When testing with a Helium sniffing process the pressure inside the test object is increased with gas containing Helium.
Process description for Helium sniffing
- Seal all openings on the test object except for a single port for filling with helium.
- Evacuate the internal volume of the part with a vacuum pump.
- Fill the test objects inner volume with Helium to a specific pressure
- Scan the test part with a Sniffer instrument checking for leakage
- Evacuate the internal Helium gas and ventilate the product. Avoid contamination of gas to be built up around the test fixture.
- Disconnect sealings and connectors.
Helium sniffers are often integrated in mass spectrometers and used to search for leak locations when testing products in a vacuum chamber.