Mailing List Archive Mailing List Archive
At 09:16 AM 4/8/99 -0700, you wrote: >Frank, > >>Not me, but I do let the filled tanks rest a day before analyzing. An if >>you want to tell me >>thats not neseccary I recommend that you try this: Fill oxygen, top with >>air, wait a minute, >>analyze mix, turn the tank so that the valve faces ground, wait another >>minute and than >>re-analyze the mix. > >And it's the same... or not? >When filling a tank the temperature and pressure are high which in turn >gives a high diffusion coefficient. Makes the mix homogeneous almost >instantaneoulsy (couple of seconds). >What kind of differences do you get? >What kind of analyser do you use, are you sure the hoses are drained when >using a regulator or something? > >Regards,> >THOMAS I have witnessed Nitrox mixtures take a while to fully homogenize. Several years ago while mixing 80/20, (Yeah I know don't start) it came out 63% O2 approx 30 min after the very s-l-o-w top off to fill pressure. Yes I checked the calibration of the aynalizer (Teledyne TD-50). Each time I would check the O2 reading would climb. I did this over a period of several hours. Later it was right on 80%. I'd have to say stratification can and does occur, esp. if there is not enough turbulence during top off. I have never seen this with Trimix as the fill rates are much higher. However I suppose it could occur if they too were topped slowly. At any rate I never seem to dive my gas until they show the correct mixture. "SILT HAPPENS"JD JEFF DISLER SAFE CAVING NSS 26000 -- Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.
Navigate by Author:
[Previous]
[Next]
[Author Search Index]
Navigate by Subject:
[Previous]
[Next]
[Subject Search Index]
[Send Reply] [Send Message with New Topic]
[Search Selection] [Mailing List Home] [Home]