I may have stumbled on a really good solution.
I am using PVC pipe, from the lower chamber to top of the upper chamber (see photo below)…
I have this Rockler hose which has really good “expansion” (a tight spring). Notice the difference in the compressed section and the expanded section (expanded due to the adapter). Rockler claims 4x expansion, and that seems accurate. I cut the hose to the length I needed.
In the above photo the router is in the position where the hose needs to be compressed the most (Router directly below the PVC port, Z axis all the way up).
And here is a picture with the router in the home position, with plenty of hose expansion left (unused).
I did need to purchase an additional 2 1/4" adapter, but the adapters are nice in that they also rotate.
I also take a very aggressive approach to grounding my CNC (Thank you @LiamN - Grounding your Shapeoko). I cut away the outer liner at the very end of the hose and soldered a ground wire to the spring within the hose (notice the copper/white wire at the end).
