HPA and Co2 mix- someone around here somewhere has done this...

[Voltar1]

AT44 tube with CO2 added until liquid vents while horizontal
Air added to 2000psi
Stabilized at home19 cel 110bar on tank gauge
Outside in sun at 25 cel 125bar
Warming in sun to 30 cel 150bar

1034.6 grams weight will weigh when empty .......

[Voltar1]

that is wonderfull. I did try it a few times but after getting the my qb modded to shot 270 in one fill of hpa it was not worth it for the QB.
but on the other hand the Disco is a different story. I get up to 28 full power shots but mostly from 22 to 25 shots. so the co2 hpa mix would be great for this.
I can tell you this maybe it will help in ur calculation.

I fill my 13ci tank with co2 was about 900psi then I pump it up too 1500psi with hpa and i did that about 3 times had a great shot count but was too much work so I modded the hammer spring with some of the forum help.
so I know full of co2 and 1500psi was safe in a 3000psi tank regulated at 850psi

Frank pressure will not tell you how much CO2 is in that tank. Have to weigh it before and after.

[AirGunEric]

I'm not sure if I'm regretting asking the question in the first place at this point...

[SeanMP]

My apologies to anyone who now has a headache

[FRANK]

I know I was filling it with co2 till presure equalized and that is about 900psi for co2 at room temp.
and then pump air [ hpa] too 1500psi

but I would like to know if I can fill my Disco with co2 and then top it off with air [ hpa ] too 2000psi and call it a day at the FT.

[rsterne]

Stabilized at home19 cel 110bar on tank gauge
Outside in sun at 25 cel 125bar
Warming in sun to 30 cel 150bar

With those results, I'm thinking that there is still liquid CO2 in the tank.... For air, the expected pressure change from 19*C to 30*C would be very little....
19*C = 292*K.... 30*C = 303*K.... 110 bar x 303 / 292 = 114 bar.... If what Sean and I were talking about with a mixture of two supercritical fluids was true, I'm thinking we would expect a similar (ie very small) change in pressure....

If we look at the CO2 chart, and find where 110 bar (1595 psi) crosses 19*C (66*F), it's in the middle of the blue area, where a tank with pure CO2 would be 130% full.... If we then slide straight up to 30*C (86*F), the pressure (for pure CO2) should be off the chart (over 2500 psi).... The pressure at 30*F was actually 150 bar (2175 psi), which would put the tank at 125% full.... That's pretty darn close to predicted behaviour for CO2 in the 100% liquid state.... Based on that one experiment, I'm back to believing that once you pressurize a half full CO2 tank with air to 2000 psi, it acts like you shrank the size of the tank.... If you think about it, the CO2 molecules shouldn't be able to tell what they are colliding with billions of times a second.... a metal tank wall, or nitrogen and oxygen molecules.... Maybe my theory about the air creating a "flexible" tank isn't so far fetched?.... If it turns out that it isn't that "flexible" there could indeed be a safety concern as Steve in NC suggested....

The one thing that confuses me with Voltar's data is why did the pressure drop from 2000 psi to 110 bar (1595 psi) when it stabilized at 19*C?.... More tests need to be done to insure safety, IMO.... After all, an 11*C change of temperature raised the pressure from 1595 psi to 2175 psi.... If we were talking about a properly filled CO2 tank the corresponding pressures would have been ~800 psi and ~1150 psi.... Food for thought....

Bob

[Voltar1]

Different gauges 2000 on the fill whip = 110bar on the reservoir
I could hear liquid sloshing in the tube

[Voltar1]

I know I was filling it with co2 till presure equalized and that is about 900psi for co2 at room temp.
and then pump air [ hpa] too 1500psi

but I would like to know if I can fill my Disco with co2 and then top it off with air [ hpa ] too 2000psi and call it a day at the FT.

Frank, you were most likely only getting gas into that little tank as there is no way to vent off the vapor space. Without a scale you do not know if any liquid is in the tank.
Same for the Disco, without a method or equipment to allow determining liquid content I would not advise trying to CO2 into the gun then adding air.

That disco double holds promise for this eh?

[FRANK]

if you hold a co2 tank upside down liquide co2 goes in.

[Voltar1]

Walter seems to have taken quite a bit of heat on that one. I do like his doubled shot count on the mix vs. plain HPA or plain Co2...

if you hold a co2 tank upside down liquide co2 goes in.

Ok Frank, how much goes in?