Here's a link to a source for The Oxygen Hackers
Companion (which Alec Smyth recommended) as well as other relevant
publications. It's only $35. One copy is on Amazon for
$300+.
In a message dated 5/6/2012 1:05:29 P.M. Central Daylight Time,
vbra676539@aol.com writes:
Good to know we have someone in the group who has actually
beat his head against that particular wall. Thanks Sean. Good info.
Vance
-----Original
Message----- From: Sean T. Stevenson <cast55@telus.net> To:
personal_submersibles <personal_submersibles@psubs.org> Sent: Sun,
May 6, 2012 1:52 pm Subject: Re: [PSUBS-MAILIST] O2
Scott, I have been
dealing with issues like this with gas suppliers for years. The purity
issue is nonsense. The medical grade oxygen is filled from the same bulk
cryo storage as the industrial stuff. The difference is that medical
grade is periodically sampled and analyzed for compliance with USP specs,
which adds a cost overhead, and on the medical grade, the filling procedure is
slightly different - vacuum is pulled, O2 is flushed at low pressure, vacuum
is pulled again and then the cylinder is filled. Industrial cylinders
either have one or no vacuum steps before filling. The idea is to avoid
any kind of hydrocarbon contamination, but such risk is small. I have
been using industrial helium and oxygen (run through my own physical and
chemical filters) for years without issue. If you can do so, it will
probably be cheaper. If not, just explain your situation to your GP and
you can probably get a prescription. Another option to look for is
so-called aviator's oxygen, which is certified to have minimal moisture
content (prevents freeze-up issues), but may not track other impurities and so
may be cheaper than medical. For submarine breathing media, industrial
grade gas is fine provided you confirm the analysis (make sure it's actually
O2 in the tank at 99.5+ %). The breathable atmosphere in your sub is
exposed to external contaminants anyway from your body, clothing, equipment
and any dirt you may have tracked in. Since you are conditioning the air
anyway (via CO2 scrubbing), for peace of mind you could include other media
stages in your filter for scrubbing hydrocarbons, CO,
etc. -Sean On 2012-05-06 07:53, swaters@waters-ks.com wrote:
I was at my local welding and gas supply the other day and they were
asking me how my sub was doing and we got on the conversation about the life
support system and how it works. They told me they could not sell me medical
grade oxygen with out a prescription from a doctor which I thought was kind
of weird. They said I might be able to use oxygen that you use for welding,
but it is not as pure. Does anyone on psubs have any ideas on what to
do?
Also I had asked a question a while back about the tubing in the K-350.
I have decided to go with stainless steal, but was still wondering what
wall thickness to go with and how do you connect them (flair fitting,
compression fitting, or something else?)
Thanks,
Scott
Waters
|