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--------------8401EC356D6BDA42C55A12F3 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit I have a general question for the list dealing with the compressablity of the various gases used for mixed gas diving. I have found by experience (and Georges video) that ideal mixes of gas do not normally come out exact. When using electronic gagues I find that I can be quite accurate with the mixes. Unless I allow for the different compresibility factors of the component gases in the mix then there can be significant variance in the target mixes. This is particulary noticable in mixes with a high target fill pressure (3000PSIG+) with a high helium content. Another big factor of course is the temperature. I find that if I mix up in my garage on one day and take my tanks to the shop to get topped up the next then there can really be a significant variance particularly if they toss them in the tank to fill them to my requested target pressure. For the dive shop I normally frequent I have more or less have them trained now to just fill them nice and slowly outside of the tank when they have the time. But in situations where on remote locations where I am filling here and going there I can not always controll the temperature. I can eyeball it (as I do now with the O2 and He ratios) and come up fairly close. What I was wondering if there were any gas gurus around that have access to the formulae that allow one to adjust compressiblitiy factors and temperature? I know that this is a little anal but I wanted to include this in a blending software package I am developing I thought that it would be a nice addition. Dan. --------------8401EC356D6BDA42C55A12F3 Content-Type: text/html; charset=us-ascii Content-Transfer-Encoding: 7bit <!doctype html public "-//w3c//dtd html 4.0 transitional//en"> <html> I have a general question for the list dealing with the compressablity of the various gases used for mixed gas diving. I have found by experience (and Georges video) that ideal mixes of gas do not normally come out exact. When using electronic gagues I find that I can be quite accurate with the mixes. Unless I allow for the different compresibility factors of the component gases in the mix then there can be significant variance in the target mixes. This is particulary noticable in mixes with a high target fill pressure (3000PSIG+) with a high helium content. <p>Another big factor of course is the temperature. I find that if I mix up in my garage on one day and take my tanks to the shop to get topped up the next then there can <u>really</u> be a significant variance particularly if they toss them in the tank to fill them to my requested target pressure. For the dive shop I normally frequent I have more or less have them trained now to just fill them nice and slowly outside of the tank when they have the time. But in situations where on remote locations where I am filling here and going there I can not always controll the temperature. I can eyeball it (as I do now with the O2 and He ratios) and come up fairly close. <p>What I was wondering if there were any gas gurus around that have access to the formulae that allow one to adjust compressiblitiy factors and temperature? <p>I know that this is a little anal but I wanted to include this in a blending software package I am developing I thought that it would be a nice addition. <p>Dan.</html> --------------8401EC356D6BDA42C55A12F3--
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