I left out another part of my thinking when I posted.  You could always
pump in the Helium then top with air or another pre mix NITROX.  The
shop I frequent currently only has NNI and NNII.  The plans are to also
include 28% and 40%.  Might not lead to an optimal mix but you might be
able to get an adequate mix out of using it.  My tanks aren't O2 cleaned
but I can get most mixes up to 36%.  Just use either 32 or 36 to a
certain pressure then air top to desired fill pressure.  2200 of 32%
then top to 3500 with air will yield 28% for example.  Think the same
principle could be used for Tri-mix.

Safe diving,
Art.
art.paltz@r2*.co*
Last Dive 10/4/97, The Stolt, NJ, 125ft/40 min bottom time, 57 degrees
F, 28% bottom mix, 50% deco mix


	-----Original Message-----
	From:	Todd Leonard 
	Sent:	Thursday, October 09, 1997 3:29 PM
	To:	Paltz, Art
	Subject:	Re: Tri-mix and O2 cleaning for the novice

	Nope, no need to O2 clean the regulator for a mix below 40%.
The 
	only interesting question is about the tanks, which may contain
>40% 
	at some point when you're partial-pressure blending.  Some
people 
	will tell you that your tanks should be "O2 cleaned" for that,
and 
	some say that either your tanks are clean enough for breathing
or 
	they're not and that special "O2 cleaning" and costly and
proprietary
	labeling is nonsense.

	- Todd


	> Art (trying not to be a stroke) writes,
	> 
	> Caveat:
	> I'm not debating the need to O2 clean anything!!  I don't have
a cascade
	> system or know anyone who does.  I don't do enough diving to
warrant the
	> cost IMHO.  I dive about once a week (2 tank boat) between the
months of
	> May and October, then about 1-2 times a month during the
winter.
	> Already had to "dedicate" a set of tanks for NITROX since only
NITROX
	> stations will fill them with the sticker on!  Lets ASSUME you
need to O2
	> clean things for more than 40% O2(just for a moment).  I do
since I rely
	> on the need to have tanks filled at a shop.  
	> 
	> 
	> Was thinking about something, it's very scary!  :-)  My
question is
	> this.  Without being tri-mix certified or knowing much about
it, if
	> you're not going to dive more than 40% O2 with tri-mix (don't
think this
	> makes sense anyway), do you need to O2 clean the reg.??  My
(sometimes)
	> logical minds says "no way".  I don't believe Helium is
combustible, is
	> it (assume I failed chemistry 101 :-))?  My thinking is that
if I'm
	> running a mix of say 20% O2, 40% nitrogen and 40% helium I
wouldn't
	> "need" to have an O2 cleaned reg.  I'm only using this mix for
example
	> purposes, have no idea if it would be optimal for any profile.
Please
	> no flames, not making a statement, only posting a question.  
--
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]