On 11/23/2014 07:34 PM, Steve Butler wrote:
On 11/23/2014 07:34 AM, Dirk Hohndel wrote:
On Sat, Nov 22, 2014 at 11:30:33PM -0800, Steve Butler wrote:
Deleted last dive so I could import from DC. It came in without the
default
tank from my preferences (HP119).
In addition, when I selected HP119, the cu ft is not 123 (the
manufacturer
of my XL-119 tanks claims they have 123 cu ft at 3442 #). I have
verified
that all occurrences of HP119 in my dives have been modified to show
123.
Is there some other place I should change?
What's the wet volume of that tank? It's possible that the manufacturer
gives the gas volume based on the ideal gas law (i.e., wet volume
multiplied with the pressure in bar). But air doesn't behave like an
ideal
gas at higher pressures. We try to calculate an approximation of the
real
behavior of air (look at surface_volume_multiplier() in dive.c) which
gives a lower gas volume at higher pressures as you would assume by
simply
using the ideal gas laws.
/D
The specs are: http://www.xsscuba.com/tank_steel_specs.html
The Nominal Capacity at
http://www.xsscuba.com/tank_steel_specs_metric.html is what we need.
15.3 liters should be 0.54 cuft. @230 Bar the ideal gas is 124.34.
The Z-factor for air at 250 bar and 300 K (little warm for room temp)
is 1.0669.
The Z-factor at 200 bar/300K is 1.0326. I'd estimate the Z-factor
around 1.05 for 230 bar. Just an eyeball would put the "real" around
119.
<<sigh>> and here I wanted to believe the manufacturer especially
since their 120 tank is listed as having 120 cu ft and costs $25 more
at my LDS.
--Steve
So I'm guessing the True Volume from the first web page is the ideal
gas calculation. However that implies to me that the actual capacity
is 116 cu ft (124.34/1.0669=116.55).
However, we are not at 250 bar so looking down at 200 bar with a Z
factor of
Been a long day. Obviously that lower part was supposed to have been
removed.
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