Because It's Precious - Gas Mixing Systems for Helium Leak Testing
For testing sensitive products, which have to be absolutely leak tight, tests using gases have become widely accepted. For error checking, products are tested with helium, for example. If gas escapes from somewhere at the product, it is defective.
Only with additional systems for helium conditioning, in which the precious inert gas can be recovered almost completely and thus used again, can helium be used cost-effectively.