Q on blending gases

[swyzr191]

I'm looking for some answers on blending Argon and Co2.
Has anyone used flow meters to make their own 98%Ar/2%Co?
It seems I use C-25, 100% Ar, 98%Ar/2%Co2 and 92%Ar 8%Co2.
I would rather get set up to blend Argon and Co2 as opposed to having a bunch of different bottles.
Also if I blend my own, I won't be concerned with the gases seperating over time.

Has anyone gone down this road?

[fun4now]

flow rates

im just guessing here but it seems that at the preshure rates used i dont think you could get your flow meeters to do the trick. i think we would all prefer to have less bottels around bolth for space and $$$$$ reasons but you would have a lot of messy welds trying to dile it in and you would have to start over every time you changed processes. best to stick with premixed to keep a good mix rasheo.

[klsm54]

In theory, using flowmeters to mix gas would be ideal, but it would not be as simple as it sounds. The gases, CO2 and argon have different specific gravities and expansion ratios so just setting the flowmeters at say 1 CFH and 50 CFH may not give you the 98/2 mix you would desire.

On the other hand, there are lot's of commercial mixers available that have the calculations done for you and also have expansion chambers to assure the same mixture through varying flows. Here are a few examples.

Concoa Autoblend

Thermco Mixer

and a smaller version more suited to the one or two man shop.


Smith 180CFH Mixer