Tank Volume

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Assume we are at a constant environmental presure (sea level) for all of this.

Suppose a bag (your lungs) is attached to a fairly long hot tube (your wind pipe) and at 37C it takes 1 unit of gas to inflate the bag. This tube is attached via a presure control device (regulator) to a tank with 10 units of gas mesured at 37C. The tank only has the volume for 1 unit of gas at 37C, so the gas is under presure (10atm).

Say this tank is cooled to 10C. The presure will decrease in the tank according to the gas laws. We manipulate the presure control device to release some gas, enough gas to fill the bag. That gas is warmed along the way and expands (gas laws).

Say we have another tank at 20C. The same procedure happens. Did more or less gas come from the tank? No, the bag still has the same 1 unit volume, and the gas is still warmed to the same 37C temp.

Do they both get the same # of breaths?
How much gas are the removing from the tank with each breath?
Does that make sense?

That is an ideal world. In the real world, the gas is not completely warmed, the bag is elastic, its volume can be controlled, the regulator has resistance, the gas takes energy to warm, etc..

Would there be a diference, yes.. but not much, and likely not mesurable.
 
I just want to say thank you to all the people how took the time to read my posting and give there thoughts

Thanks,

125 lover

Oh bay the way I love my OMS 125


:)
 
Originally posted by JimC
Assume we are at a constant environmental presure (sea level) for all of this.

Suppose a bag (your lungs) is attached to a fairly long hot tube (your wind pipe) and at 37C it takes 1 unit of gas to inflate the bag. This tube is attached via a presure control device (regulator) to a tank with 10 units of gas mesured at 37C. The tank only has the volume for 1 unit of gas at 37C, so the gas is under presure (10atm).

Say this tank is cooled to 10C. The presure will decrease in the tank according to the gas laws. We manipulate the presure control device to release some gas, enough gas to fill the bag. That gas is warmed along the way and expands (gas laws).

Say we have another tank at 20C. The same procedure happens. Did more or less gas come from the tank? No, the bag still has the same 1 unit volume, and the gas is still warmed to the same 37C temp.

Do they both get the same # of breaths?
How much gas are the removing from the tank with each breath?
Does that make sense?

That is an ideal world. In the real world, the gas is not completely warmed, the bag is elastic, its volume can be controlled, the regulator has resistance, the gas takes energy to warm, etc..

Would there be a diference, yes.. but not much, and likely not mesurable.


Nice, you are filling the same volume of space at the same temperature hence the same amount of gas is needed and since each started out with the same mass of gas both will get an equal bottomtime provided the diver in cold water has the same breathing rate of course and lung volumes are equal.
So, with ALL parameters the SAME even in a non-ideal world both divers would have equal bottomtimes available.

it is interesting to see how new divers leave a diveshop with a
3400 psi fill, get to the water, see a 3000 psi reading and think they have less air in their tank than they left the shop with.
pressure alone does NOT tell you the available amount of air.:D
 
https://www.shearwater.com/products/peregrine/

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