He valves
andreww said:
Thats what I thought. To stand pressures down to 1000 meters, the watch would naturally have to have a pressure release valve to keep it from exploding.
The He valve is not to stop the watch "exploding" due to the extreme depth of a dive (whether as a diver or inside a sub), exactly.
You likely know that as divers go to great depths, they need to use exotic gases to manage physiological effects such as nitrogen narcosis (even good ol' O2 can become toxic under pressure). Helium is used (helium saturation) in the air mix to mitigate these toxicity effects, and the small gaseous particles get inside the watch -as they can squeeze past the water/dust O-rings, being smaller.
Once depressurized (ie on ascending from deep dives) the He particles must escaoe - or their 'need' to escape/expand will cause a massive pressure build-up inside the watch case - so the He valve operates to release this pressure, and avoid problems like exploding the crystal.
-- BBB