How do you perform a helium leak test on a vacuum furnace?

Finding leaks in vacuum furnaces is a task that few people look forward to, however it is important and necessary. Leaks happen almost always and can occur suddenly or develop over time. They can damage both the material being heat treated as well as internal furnace components. When left unchecked leaks will stop the furnace from pumping down and will compromise the heating elements. Small leaks often go undetected since the pumping system can overcome them, but they can still cause continuous and eventually catastrophic damage. It is therefore highly recommended that routine leak checking and repair be a part of any good preventative furnace maintenance program.

An Excerpt: “Why is helium used to detect leaks? Helium is used as a tracer gas to detect leaks for several reasons. These include the fact that it constitutes only ~ 5 ppm in air so that background levels are very low. Helium has also relatively low mass so that it is ‘mobile’ and is completely inert/non-reactive. Helium is also non-flammable and generally widely available and low cost. This association with helium is one of the reasons why one of the most accurate and rapid leak detection methods employs helium as the tracer gas and a mass spectrometer for the analyzing/measuring. Furthermore, helium is chosen as a tracer gas because it is light, very quick, and absolutely harmless.” >> Continue Reading