And then you need to filter the output of the bubbler because microparticules will be suspended in the gas flow, and then you need to sterilize it, because you don't know what's growing in the bubbler, and then cool it down (is sterilize by heating it), and then you need to regulate the pressure of volume, etc....
hacking-rig an industrial oxygen generator is a very different thing from being able to generate breathable medical oxygen - when you're done with all the steps you'll end up at something that's very expensive and difficult to maintain in the end
That's natural, all breathing apparatuses already have to be treated like that. Having to washing the bubbler once in a while if a by far the better option to dying.
> When you're done with all the steps you'll end up at something that's very expensive and difficult to maintain in the end
