Why does a watch need a helium valve?
The helium valve is a safety valve specially developed for diving watches, which allows helium to escape from the watch case during decompression. Divers working at great depths use diving bells or other pressure vessels. A high proportion of helium is added to these pressure vessels. The helium atoms are very small and penetrate into the watch due to the overpressure through the seals. When the pressure vessel, for example a diving bell, is brought back up, the pressure in the pressure vessel is continuously adjusted to the level of the environment. During the surfacing phase, human tissue releases helium faster than it can escape from the waterproof diving watch. An enormous overpressure builds up inside the watch. To prevent the watch from being damaged due to the overpressure, the helium atoms that have penetrated must be released again. This is then done via the helium valve. The helium valve was patented by Rolex in 1967 and is today an indispensable requirement for deep diving.