pressure/volume question

[dc4bs]

See, that's why I ask questions.

So I can find out where my thinking is wrong. I dunno why I let myself get locked onto the idea of an arbitrary number like 40 ft3 as a 'must have'.

I gotta go back and rework the problem from the angle of 'exactly what do I need for the diving I'm doing' and go from there.

Looks like I'll be getting the AL 40's after all.

Thanks for the input guys.

 

[AquaTec]

dc4bs once bubbled...
Hi all,

Given constant volume and temperature, is the pressure vs. compressed volume equation linear or a curve?

For example:

A 'standard' 80 ft3 Aluminium scuba cylinder at operating pressure of 3000 lbs/ft3 contains roughly the equivalent of 80 ft3 of gas at 1 Atm

The same cylinder at 1500 lbs/ft3 has how much gas at 1atm equivalent?

If it is a linear equation, it would be about 40 ft3.

If it's a curve, can someone point me to a formula, or better yet, a souce where I can get to understand the pressure, static container volume, compressed gas volume relationship better?

Air inside a closed cylinder is not subject to Boyals law as the ata do not change. so in your formula, a tank the contains 80 cu/ft at 3000 psi when filled to 1500 psi would be 50% full therefor it would contain 40 cu/ft.

the air is not subjet to the pressures outside the tank.

mind you the gas law that has to due with temprature change does apply, if you leave that 1500 psi tank in the sun and the temprature rises i beleive that the formula is 1 psi per 1 degree ferenhiet in temp difference. therefor the cu/ft would also change porportionaltly


now if the tank was a flexible one say a balloon the or other closed flexable container then the veriouse gas lawas would apply