I took some time today while we were working on the rest of the project to design up what I think will be a workable fixture for the air filters. The cone on the front is a to-scale approximation of the air filter I have right now. The cone on the back end is an approximation of the air bladder. There’s actually an interior PVC tube modelled in there that I expect to connect.
This is being designed in this way so that I can use it as the actual air intake for the fans that will be in the airbag behind my head blowing air into the mask. The part should have a pretty straight connection through between the filter and the airbag, and I did my best to keep it from narrowing too much smaller than the 40mm tubing that leads to the 40mm fans.