volume differences between tanks

[novasquid]

if a 120 cubic foot tank is 1.5 times larger than an 80 cubic foot tank, does that mean it's 1.5^3 or 3.375 times the volume (assuming they're both filled at their rated psi)?

 

[JohnN]

if a 120 cubic foot tank is 1.5 times larger than an 80 cubic foot tank, does that mean it's 1.5^3 or 3.375 times the volume (assuming they're both filled at their rated psi)?

Assuming the HP120 and HP80 are filled to the same pressure, the HP120 has 50% more capacity (1.5 x 80 = 120)

If you're trying to compare HP and LP tanks, then because air at ~3500 PSI doesn't behave as an ideal gas, the difference is somewhat skewed (depending on which tank in the example is LP)

 

[novasquid]

wouldn't it be 1.5^3? for example 2 cubic foot compared to 1 cubic foot is 2^3 or 8 times the volume, not just 2x.

 

[JohnN]

wouldn't it be 1.5^3? for example 2 cubic foot compared to 1 cubic foot is 2^3 or 8 times the volume, not just 2x.

Very odd math you're using, 2 ft^3 is twice 1 ft^3

 

[tursiops]

The dimensions of the tank are not the issue; The issue is the 120 cf versus 80 cf. That's all that matters for the volume carried by the tanks. Trying to compare dimensions ignores wall thicknesses, material, pressure and engineering safety factors.

 

[novasquid]

Very odd math you're using, 2 ft^3 is twice 1 ft^3

i think i'm getting my terminology mixed up. i was imagining a 2 foot cubed is 8x the volume of 1 foot cubed.

 

[tursiops]

Very odd math you're using, 2 ft^3 is twice 1 ft^3

?? 2ft to the 3rd power is 8; 1 ft to the third power is 1.

OP: when you hypothesize 1.5x bigger, do you mean just the diameter? if so, then you want to square it, not cube it. If you mean 1.5x longer, then it is just 1.5x the smaller one. But none of that is relevant...see my post #5.

 

[novasquid]

?? 2ft to the 3rd power is 8; 1 ft to the third power is 1.

OP: when you hypothesize 1.5x bigger, do you mean just the diameter? if so, then you want to square it, not cube it. If you mean 1.5x longer, then it is just 1.5x the smaller one. But none of that is relevant...see my post #5.

i just meant the volume differences when people talk about tank size, 80 versus 120 for example. since we're talking volume, from a simple math and numbers perspective, does that mean a 120 tank is 1.5x the volume of an 80? or is it 1.5^3?

 

[novasquid]

i think i'm seeing what john meant above. 2 foot cubed is 8x the volume of 1 foot cubed, but 2 cubic foot is 2x the volume of 1 cubic foot.

 

[tursiops]

i just meant the volume differences when people talk about tank size, 80 versus 120 for example. since we're talking volume, from a simple math and numbers perspective, does that mean a 120 tank is 1.5x the volume of an 80? or is it 1.5^3?

If the tank are spheres and both are the same material/construction, then you'd expect the 120 cf tank to be the cube root of 1.5 "larger." Not the cube! But you keep trying to base things on dimensions....but the issue is volume, and that is totally encompassed by the 120 cf and the 80 cf....so the former is 1.5x the volume of the latter....regardless of size, shape, material, etc.