[Balloons] FW: [GPSL] Hydrogen usage

Don - KM0R km0r at km0r.net
Fri Oct 25 19:59:48 CDT 2013


Thought some of you might find this thread interesting.

Don - KM0R

-----Original Message-----
From: GPSL at yahoogroups.com [mailto:GPSL at yahoogroups.com] On Behalf Of
Hanson, Douglas R CIV SPAWARSYSCEN-PACIFIC, 63800
Sent: Friday, October 25, 2013 11:41 AM
To: Zack Clobes
Cc: GPSL at yahoogroups.com
Subject: RE: [GPSL] Hydrogen usage

Thank you all!!! I knew the feedback would be tremendous. Now I'm that much
closer to my first launch.

Ryan

-----Original Message-----
From: GPSL at yahoogroups.com [mailto:GPSL at yahoogroups.com] On Behalf Of Zack
Clobes
Sent: Friday, October 25, 2013 8:02 AM
To: Hanson, Douglas R CIV SPAWARSYSCEN-PACIFIC, 63800
Cc: GPSL at yahoogroups.com
Subject: Re: [GPSL] Hydrogen usage

  

My regulator is a single stage, and I don't remember the outlet pressure off
hand, but you want as high as you can get, or else you could be there all
day filling.  Our balloons fill in about 10 minutes, maybe less.


As for the static build-up, I have a bit of an issue with that.  For us, we
purge our fill line and our balloon of "air" before filling the H2.  So even
if there was a spark in the fill line, there is still no oxygen to support
combustion.  I've proven that in controlled tests, and it appears that it
takes about a 50/50 ratio (+/- 20-30%) of oxidizer and H2.


To further support this, I (and probably most others) vent our bottles
before returning them to the supplier, and I never use a regulator at that
point.  I would submit that this is far more dangerous than filling a
balloon.



*	Remember that the 2000psi cylinder is your most dangerous component.
*	Fill outdoors.
*	Have an extinguisher handy (not for the H2, but for the latex that
could catch fire and fall back to the ground).
*	Be aware.


Zack Clobes, W0ZC
Project: Traveler
www.projecttraveler.org




On Fri, Oct 25, 2013 at 9:42 AM, Hanson, Douglas R CIV SPAWARSYSCEN-PACIFIC,
63800 <douglas.r.hanson at navy.mil> wrote:


	All,
	I would like some help determining the safest use of hydrogen.
Hydrogen providers often caution me about static charge buildup if the flow
rate into the balloon is too fast. What is considered a safe fill rate? How
long should I take in filling a 1600g Hwoyee (assuming I'm only using about
210cu.ft. of gas)? There are many CGA 350 regulators available, but does the
outlet pressure of the regulator matter? Single stage or two stage? I look
forward to the great feedback. Thank you.
	
	Ryan, KJ6YXG
	San Diego Near Space Project
	






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