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13646Re: [GPSL] Hydrogen usage

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  • Mike Manes
    Oct 25, 2013
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      Hi Ryan,

      All the advice from the other respondents is quite sound. EOSS takes
      one more, perhaps paranoid, step, and that's to lightly dampen the
      envelope and fill tube with a lawn spritzer before starting the fill,
      and again until the envelope lifts its own weight. This suppresses the
      most insidious source of ignition - an electrostatic discharge.

      Once the envelope has plumped out, we kick up the fill rate to max,
      sans regulator, using the tank valve to regulate the flow. If there's
      any breeze, a slow fill creates the greatest hazard that a latex bag
      is exposed to until burst, since that increases the chances of the
      envelope hitting the deck or sharp jewelry on the handlers.

      We abandoned regulators after experiencing entirely too many freeze-ups.
      Our fill hose is 1/2" ID and 20 ft long reinforced rubber air hose - so
      plenty of carbon black in the walls to dissipate any generated
      electrostatics.

      73 de Mike W5VSI

      On 10/25/13 8:42 AM, Hanson, Douglas R CIV SPAWARSYSCEN-PACIFIC, 63800
      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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