Mass spectrometry leak testing - is rapid and does not impose mechanical stresses of vacuum testing

摘要

Tracer gas usually helium is sprayed on the exterior of a vessel to be leak-tested, the pressure inside the vessel having been reduced to slightly below atmospheric by a suction pump. The line between the vessel and the pump goes via a tee junction having a branch leading to a mass spectrometer through a selective membrane which is permeable to tracer gas but not to other gases in the vessel. Because of the very slight reduction of vessel pressure, sensitive testing of industrial vessels and pipe systems can be carried out very rapidly without the stresses associated with high vacuum testing techniques.