The He valves have nothing to do with depth or water resistance. They only function when living in and decompressing from a pressure depth environment. The He valve will function and do it's job even in a dry saturation living condition. The deep tunnelers use them as well as commercial divers.
Watches that are oil filled, besides being rated for astronomical depths, actually eliminate the need for an He purge valve because the He can not displace the fluid inside the watch. For the Commercial saturation diver or a deep tunneler, this is the best choice if he insists upon wearing a watch. The work environment is very hard on a watch however. Most of the tools create heavy vibration and we swing a lot of hammers down there. Most of the divers watches rarely get wet.
Watches that are oil filled, besides being rated for astronomical depths, actually eliminate the need for an He purge valve because the He can not displace the fluid inside the watch. For the Commercial saturation diver or a deep tunneler, this is the best choice if he insists upon wearing a watch. The work environment is very hard on a watch however. Most of the tools create heavy vibration and we swing a lot of hammers down there. Most of the divers watches rarely get wet.
°°°
