Woah good question I was thinking of redesigning a Russian re-breather
for a high altitude jump and I had not considered this issue. Duh! It
get's cold in near space. LOX is cryo and cold as it is but it could be
a factor freezing a LOX valve at high altitude.
It was just something I was thinking about not something I'm doing yet.
But no I hadn't considered that yet.
I wonder if astronauts use LOX? If so how would they do it in 0 G?
Yeah I guess they use an expansion tank to insure they get gas rather
than liquid.
My dad made me a tank from an old fire extinguisher back in the day (was
9 years old then) when we used the old Lloyd bridges style dual hose
regulators (US Divers) and if you got a pin hole in the diaphragm it
could freeze up from moisture in your breath and in the system.
I despise cold so I never dove in cold water.
-------- Original Message --------
Subject: [AR] Re: scuba or astronaut gas temperature question
From: "" <dmarc-noreply@xxxxxxxxxxxxx> (Redacted sender
"JMKrell@xxxxxxx" for DMARC)
Date: Fri, August 21, 2015 10:07 am
To: arocket@xxxxxxxxxxxxx
John,
The compressed air temperature drop will be approx 30 C from 200 to 1 bar.
Reference T-s diagrams for N2. The largest T drop occurs at the first
stage of the regulator, 200 to 10 bar. In water >10 C the 10 bar air is
reheated to near water temperature. Diving in water at temperatures <5 C
does
present a regulator freeze issue. Special regulators and procedures are
required.
Dumping a full dive tank will not produce snow in the summer. Done that.
SCUBA air dew point of -53 C (<24 PPM H2O).
Krell
In a message dated 8/21/2015 7:05:51 A.M. Pacific Daylight Time,
johndom@xxxxxxxxx writes:
Is there an expansion due air (gas) temperature drop, say from a 200 bar
cylinder to a diver’s mouthpiece after the pressure regulator? Like a JP
expansion effect? Of course with scuba diving, the regulated pressure is
depth
dependent, but still. Any values in °C?
jd