air does not flow through a pipe

This happens because you have 2 outputs on opposite ends of the pipe.  The way pipes work in this game is it makes a path from every output to every input,  if you have 2 paths going in opposite directions, pipe contents wont flow correctly. All your outputs need to be grouped on the same side, so that theres only one path gas could take to get to all the inputs

 

Having so many junctions in a line like that is pretty bad as well, since every junction alternates packets. meaning 1/2 of packets will go to the first station, 1/4 to the 2nd, 1/8 to the 3rd,  1/16th to the 4th etc,  meaning the last 2 stations in line will only be getting something like every 128th packet of oxygen when all stations are charging.

Edited October 30, 2017 by Townkill