Watches with a helium valve are intended for divers who spend long periods of time on board a diving bell (pressure chamber, decompression chamber) or in another room where air is enriched with helium to make breathing easier. The noble gas helium is one of the smallest molecules and has the property of penetrating the seals of watches and thus entering the case. Once inside the case, the gas cannot escape again in the same way without the special valve – the helium valve. Opening the valve prevents the watch from being damaged by the overpressure of the helium during ascent. Various models have an automatic helium valve which reacts automatically to the overpressure.
Manual helium valves/crowns
- Before leaving the diving station, turn the crown of the helium valve counterclockwise as far as it will go (open).
Even if the valve remains open, the watch remains water-resistant for normal use. For normal dives, close the valve as described above.