New Gas Routing System

After the ninth rebuild of the oral-nasal mask, which finally sealed up all leaks and installed the inhale / exhale valves from a military MBU 20/P flight oxygen mask (photo above), I thought I had the system settled; photos of this happy moment, below.



But, as often, I was dead wrong. Fitting the inhale / exhale hoses to the Russian-made inhale / exhale ports has frustrated me for months, and as well as this new configuration seemed to work in principle, turning on the gas to breathe in and out revealed new problems with my system. The mask and its hoses are fine, but once again the ducting to the helmet ports was inadequate and would leak at high altitudes.

Staring at the pile of hoses and ducting I came to the solution at long last; why was I trying to fit the mask hoses to the helmet ports? Because, of course, on the helmet, that is were the breathing gas comes in and goes out. But I don't have to be constrained by that! Because my suit, below the neck ring, will be different from the system work with this helmet, I am going to completely seal up the helmet intake / exhaust ports and route the gas management hoses through chest vents, precisely the way I want. Streetcar-ride sketch, in the way to PSU this morning, below, shows the new arrangement. This is going to work!



The lesson: always be ready to rethink from first principles, and don't be mentally bound by existing systems.