Continues blending of Heliox

Is there anyone out there running heliox into a small portable sized compressor?? I would like to know about setups for a mixing bag and gas flow controls. I already have some ideas, but would prefer not to reinvent the wheel on this one.

caverkevin

Small compressor, no mixing bag this is not a very good idea. Use a mixing chamber for uniform mixing and to greatly reduce the risk of sending a high O2 content stream of gas into the compressor.

I keep the helium content to less than 50-55% to reduce the amount of work and heat that the compressor is subjected to. I also selected a compressor that has cast iron heads and very good interstage cooling. No problems yet with about 25,000 ft^3 of Trimix and EANx pumped through it.

Get a good 2 stage regulator for the supply bottles add a variable area flow meter to the output of the regulator and send the line to the mixing chamber. The variable area flow meters let you "see" the flow rate and make small adjustments as needed.

Remember that most flow meters are "rated" for air. If you use one for helium get one that is about half of the flow rate for air that you need. (If you need a flow meter that goes to 5 cfm for helium a 2.5 cfm for air is just about right.)

On the outlet side run the mix to an anlyzer to verify what you got.

If you are running an oil cooled unit make sure you have good filtration as well. I run mine through a water separator, a grade "E" filtration tower and then a hyperpure tower. (this will let me blow O2 into a partial tank if needed or my banked air to top off PP blended tanks.)

omar