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Re: CO2 cylinders

Hi Neil,
  Hydro is short for hydrostatic test.  A cylinder/bottle is
filled with water and pressurized to a given pressure to see
if  integrity is still within safe limits.  I do not know
what the pressure the bottles are taken to is.  Water is
used because it does not compress well, thus if a rupture
occurs, the bottle will crack or just leak, not violently
explode.  Most privately owned gas cylinders must be tested
every 12 months to comply with DOT/state/fed regulations.
Many "filling stations" won't fill a bottle that is "out of
hydro".  If you find one that will, and you feel comfortable
with that, who am I to argue <g>, but...(I think there are
some interesting accounts of what can happen when things go
wrong on the Krib)
  The filling process is relatively simple, a CO2 bottle is
put on a scale, and then filled (via a hose) until the
proper weight is attained (e.g.. 20# cylinder, holds 20#s of
liquid CO2,. now I'm not sure whether the 20#s includes the
weight of the bottle or just the CO2 (never weighed a full
one)).  Never seen it done, but I've asked the same question
at my welding supplier.

  Now a question of my own, does anyone know if the fire
dept. or brewing suppliers charge an environmental impact


Neil Frank wrote:

> Date: Mon, 02 Mar 1998 05:55:49 -0500
> From: Neil Frank
> Subject: Re: Co2 cylinders
> <snip>
> Can you please describe what is a "one year hydro?"
> Although I get my CO2 in replacement tanks from the local welding shop, CO2
> refills are done by beer joints and at some aquarium shops.
> I would be interested in the proper procedure for refilling CO2 tanks.
> Anyone know?