A pressure test that watches a gauge fall will catch a leak you could practically hear. But a vacuum chamber, a cryostat, a sealed sensor or a nuclear fuel pin can be ruined by a leak a thousand times smaller — far below anything a pressure-decay test can resolve. Neometrix’s helium leak detection system is built for that second kind of leak: the mass-spectrometer tracer-gas method that finds, locates and quantifies leaks down to roughly 10^-12 mbar.L\/s.<\/p>\n
Helium is the smallest safe, inert, non-toxic gas, and air carries only about 5 ppm of it naturally. A mass spectrometer tuned to helium at mass 4 can therefore pick a genuine micro-leak out of a very quiet background, where a larger or reactive tracer could not. Pressure decay bottoms out around 10^-3 mbar.L\/s; helium mass-spectrometry resolves leaks about a thousand times finer than that — and puts a number on them.<\/p>\n
– Vacuum (spray):<\/strong> evacuate the part, spray helium outside. The most sensitive mode, used to quantify and locate the smallest leaks. The helium mass-spectrometer detector, reference leak and pumps are specialist bought-in items. What Neometrix engineers is the system around them: the vacuum and bombing chambers, part fixturing and sealing, evacuation, helium supply and recovery, and the controls, sequencing and reporting. It sits on the same vacuum and helium competence behind Neometrix’s thermal-vacuum chambers and helium handling equipment. This is an engineered-to-order class of equipment; no specific delivered system is claimed.<\/p>\n Rarely in the detector. It goes wrong when a pressure-decay test is chosen for a part whose specification sits below its floor, when a helium-saturated chamber or leaky fixture means the instrument reads its own background, when a sniffer is swept too fast and walks past the leak, or when an uncalibrated instrument reports a number that means nothing. Hence every result is a leak rate in mbar.L\/s calibrated against a traceable reference leak.<\/p>\n
\n– Sniffer (probe):<\/strong> pressurise the part and sweep the outside with a probe. The way to locate leaks on a large or already-assembled structure that cannot go in a chamber.
\n– Bombing \/ accumulation:<\/strong> force helium into a hermetically sealed device, then measure what leaks back out — the only practical route for a part with no test port.<\/p>\nEngineered Around a Bought-In Detector<\/h2>\n
Where Leak Testing Actually Goes Wrong<\/h2>\n
Frequently Asked Questions<\/h2>\n