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>X-From_: owner-techdiver@aquanaut.com Fri Apr 09 19:20:58 1999 >Errors-To: owner-techdiver@aquanaut.com >Subject: Re: Trimix Question >Date: Fri, 9 Apr 1999 18:45:28 -0400 >x-sender: cobber@ma*.ci*.co* >From: Jim Cobb <cobber@ci*.co*> >To: "Jeff Waugh" <jrwaugh@ix*.ne*.co*> >cc: "Steve Hogan" <Steve.Hogan@tr*.co*>, <pdisler@io*.ne*>, > <silent@cu*.ne*>, "Tech Diver" <techdiver@aquanaut.com> > >Jeff- > >Sounds to me like you need some "screw-top brain therapy" :) > > Jim > I'd go with the fins because when you simlify this gas mix problem it becomes very clear that rolling isn't very effective without the fin modification. Simply: look into a tall glass of ice water while you turn the glass...the water remains in place. I suspect the coefficient of friction with liquid on a flat surface is greater than with gas. KISS I guess perhaps if you could rotate the tanks at a couple hundred rpm, you may get some significant friction and mixing but that may be more difficult than waiting a few minutes for the molecular movement to do the work for you! Nick >Sender: Jeff Waugh Date: 4/9/99 3:13 PM > >>Yes Jim, that is correct. In fact, I pulled the directions for >>installation off of >>your web site. >>1) Cut top of cylinder off with a die-grinder or other suitable cut-off tool >>2) Insert "Fin" mechanism gently into cylinder >>3) Replace top of cylinder, making absolutely sure you have the grind >>marks left >>from the removal process lined up to facilitate a proper "bond" when the >>welding is >>complete. >>4) Overfill cylinder by no less than 1500 psi. to ensure that the welding >>process >>yielded no leaks. >>5) And last but not least, roll cylinder around garage to test your new "Fin" >>mechanism. >> >>Another fine product that will ensure that you DIR! :) >> >>Jim Cobb wrote: >> >>> The inside of my tanks are smooth, and would impart no stirring action to >>> a mix. Did you weld fins inside your tanks to accomplish this mixing >>> action you say rolling tanks does? >>> >>> Jim >>> >>> Sender: Jeff Waugh Date: 4/8/99 11:13 PM >>> >>> > I'm not sure about the temperature actually being that much of an >>> >influence >>> >on the ending reading. I have found that generally low O2 % mixes such as >>> >"deep" >>> >Tri-Mix'es generally homogenize to the final desired analysis over a >>> >period of a >>> >few hours. >>> > I've found that high O2 mixes that if filled with O2 and topped with >>> >air and >>> >allowed to sit without agitation, can render an inaccurate analysis a day >>> >later. >>> >At that point, a simple "roll" around the garage will suffice to get you >>> >what you >>> >were looking for! >>> > >>> >Jim Cobb wrote: >>> > >>> >> I don't know about you guys but I think the problem we are dealing with >>> >> here is the temperature of the mix rather than stratification. As the mix >>> >> cools off the reading becomes more accurate. >>> >> >>> >> Jim >>> >> >>> >> Sender: Steve Hogan Date: 4/8/99 6:53 PM >>> >> >>> >> > >>> >> >I have run into this and have modified my mixing procedures >>> >> >so that after I add the O2 to the helium I wait 1 day (I >>> >> >usually mix at night so waiting around is not appealing) >>> >> >before measuring the O2 % (O2 & He). It is not hard to figure >>> >> >out what percentage I expect after mixing O2 with He. >>> >> >Next step is to add air, wait a few hours (usually doing >>> >> >something else) and then measure again. >>> >> >I fill about 50 psi/min so I expect to not get much mixing from >>> >> >Brownian motion. >>> >> > >>> >> >Steve >>> >> > >>> >> >-----Original Message----- >>> >> >From: Patricia Disler [mailto:pdisler@io*.ne*] >>> >> >Sent: Friday, April 09, 1999 1:14 PM >>> >> >To: S I L E N T I M M E R S I O N >>> >> >Cc: techdiver@aquanaut.com >>> >> >Subject: Re: Trimix Question >>> >> > >>> >> > >>> >> > >>> >> > >>> >> > >>> >> >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'. >>> >> >-- >>> >> >Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. >>> >> >Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'. >>> >> > >>> >> >>> >> ------------------------------------------------------------------- >>> >> Learn About Trimix at http://www.cisatlantic.com/trimix/trimix.html >>> >> >>> >> -- >>> >> Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. >>> >> Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'. >>> > >>> > >>> > >>> > >>> >>> ------------------------------------------------------------------- >>> Learn About Trimix at http://www.cisatlantic.com/trimix/trimix.html >>> >>> -- >>> Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. >>> Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'. >> >> >> >>-- >>Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. >>Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'. >> > > > ------------------------------------------------------------------- > Learn About Trimix at http://www.cisatlantic.com/trimix/trimix.html > > >-- >Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. >Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'. > > > > -- Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. 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