Here is the low-pressure air receiver tank for the Edgewater Chamber - years ago. 

"If pressure vessels could talk"

I insisted at the time on getting something big enough on the 'launch pad' to store enough pressurized gas to get us through a USN Oxygen treatment Table 6 for serious decompression sickness. 

I wanted not to have to abort an emergency treatment in progress if the single air compressor or the backup power generator failed. I sought a grandiose, nearly fail-safe 'system that gave us the most "bang for the buck." It was 10ft in diameter by 30ft tall and 50% larger by volume than the other chamber.

It stored 10,000 SCF of air at the maximum compressor output pressure of 90 psi and took about one hour to charge up. That was the minimal time it usually took to get a helicopter transfer patient from the scene to the start of treatment. We were the closest 24/7 6 ATA multi-chamber to Lake Michigan (Chicago), so I could justify the $20k expense for the tank, which was a fraction of the cost of a new compressor and saved wear and tear on the compressor during routine daily operations. Pumping against a lower pressure to store air to ventilate the chamber at the 20 psi working pressure for typical wound care treatments (20-40 psi ) instead of repeatedly cycling in the 50-70 psi, less efficient range. 

A flip of a switch could fill the tank to the higher range for a 6 ATA iatrogenic gas embolism treatment from one of the critical care specialty units on the other 6 floors of the newest building of the hospital above and below us. Way ahead of its time for a 1968 installation. There was enough air in the fully charged tank to get us down the 6 ATA within the 5-minute naval table standard. 

I witnessed a total right hemiparalysis melt away during the 5-minute descent to 165 FSW when we started treatment within 10 minutes of the ictus. Once on an elderly patient with an air embolism from intravascular access and the second time on a police diver we did a chamber dive on. No residual symptoms from either. Like it never even happened! I was seeking the Cape Canaveral Saturn Rocket look with that primary booster tank. As you'll recall, that was during the peak of NASA's space shuttle program, and it was a great marketing prop. 

The French Columnist.