Onboard air (1 Viewer)

[rgentry]

I'm interested in 2.5 or maybe 4 pound tanks with a compact
regulator. The off-the-shelf stuff is quite spendy and I am
not likely to need it very often. How about something the
size of the small fire extinguisher that uses the same
mounting brackets. In fact, I guess you could squirt your
CO2 right on a fire, since it would smother it.

 

[Dan]

I think it would be best to just try and find out how much use you could get out of the small bottle. But I am intrested in the math too, does any one know the expansion ratio for liquid co2? Maybe Stainless 40 knows.

 

[theo]

[quote author=Dan link=board=1;threadid=9901;start=msg89937#msg89937 date=1074039646]
I think it would be best to just try and find out how much use you could get out of the small bottle. But I am intrested in the math too, does any one know the expansion ratio for liquid co2? Maybe Stainless 40 knows.
[/quote]

You can estimate with the ideal gas law. V/n=RT/P. At STP a gas occupies 22.4 L/mol. (R=.082057 L atm/mol K, T=273.15 K, P=1 atm)

The MW of CO2 is 44 g/mol. The density of liquid CO2 is 1.997 g/cc. There are 29.57 cc/oz. So you can calculate how much volume 20 oz of liquid CO2 will occupy as a gas at STP:

(20 oz CO2)(29.57cc/oz)(1.977g/cc)(1mol/44g)(22.4L/mol)(33.82oz/L)=20,130 oz.

That's an "expansion ratio" of 20,000/20 = 1000

 

[IDave]

So, how many cubic inches in a fluid ounce?

 

[Tooth Fairy]

http://www.a1.nl/phomepag/markerink/engineer.htm
Nuff said

 

[theo]

[quote author=IDave link=board=1;threadid=9901;start=msg90372#msg90372 date=1074107640]
So, how many cubic inches in a fluid ounce?
[/quote]

Depends on how much a pound of butter weighs.

 

[IDave]

My wife's family is full of Engineers. That one's gonna be getting some circulation!

 

[stainless40]

I think it depends on what color the cow that gave the milk was..and remember...the cream always rises to the top