10/50 Mix blending

[NJDiver07866]

Is this possible? I see guys with CCRs dive it in their dill but with my mix calculator I don't see how it is possible with a partial blend? It says they have to remove -15 02 PSI.

I'm assuming they just drop the helium in the tank and top with air? The -15 02 is too small or is there another way they mix this.

Rich

 

[ScubaAl]

For mixing 10/50 to say 3000psi put 1500psi of helium in your tank and top off with air to 3000psi. Analyzer and go. May be an issue with compressibility of the helium that needs to be addressed, but not a big deal, by adding a fudge factor.

Al

 

[deepstops]

For mixing 10/50 to say 3000psi put 1500psi of helium in your tank and top off with air to 3000psi. Analyzer and go. May be an issue with compressibility of the helium that needs to be addressed, but not a big deal, by adding a fudge factor.

Al

Correct, outside of ideal gas laws, 10/50 is simply half air and half helium.

 

[Wookie]

10/50 is one of the mixes anyone can make (like me). Half helium and air is 10/50. 1/3 helium and 32% is 21/35. Half helium and 32% is 16/50. A little less than half helium and 32% is 18/45. Add more he for 17/45. and so on. The beauty is that you can adjust your dive computer or v-planner for the gas you actually end up with....

 

[rjack321]

I'm assuming they just drop the helium in the tank and top with air? The -15 02 is too small or is there another way they mix this.

Its saying -15psi O2 because you used 20.9% O2 as air. Which is correct but 15psi is inconsequential. Most "10/50" is 10.3/49.5 or whatever. The CCR guys are all adding O2 to this dil to make up ~16/50 to 20/50 in the loop anyway. The O2 in the dil just needs to be known and low enough for effective flushes.

10/50 would probably not be used for OC diving nowadays.