Date: Thu, 23 Mar 2017 17:33:16 -0700
Reply-To: Brett Ne <brettn777@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Brett Ne <brettn777@GMAIL.COM>
Subject: Re: advice on new propane tank
In-Reply-To: <CAMOH8L+qMqEdnrdywR6pJaap4sFfYxFXQAxq17q8vOvjYpEwJg@mail.gmail.com>
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Disclaimer: I'm not a propane person. I really question the need for
purging and, if it were that dangerous to not purge the tank before use,
the tanks would surely come from the manufacturer filled with inert gas for
liability reasons.
1. Yes, at some point during filling, there will be a gaseous mixture
capable of ignition. That ignition would require a spark. Where is that
spark going to come from? It's a steel tank whose only moving part might
be a float, which is probably made from brass. The filling apparatus is
also brass, a non-sparking metal. Even if a lightning bolt hit the tank,
the tank acts as a Faraday cage that prevents the current from passing
inside the tank cavity.
2. Even if somehow the mixture does ignite during or after filling, there
really isn't that much oxygen in that space and the resulting pressure
shock wave is not going to be that great. The steel tank is designed to
hold a high amount of pressure.
I may be wrong, and if so, I'd like to be corrected. All this talk of
playing around with filling and draining the tank with propane vapor sounds
far more dangerous than filling an unpurged tank with liquid propane.
Brett
On Thu, Mar 23, 2017 at 4:15 PM, David Beierl <dbeierl@attglobal.net> wrote:
> I've been poking around a little. One purge method is to pull a vacuum on
> the tank and allow it to fill with propane vapor; another is to fill with
> propane vapor and vent to atmosphere "several times" -- sounds like that's
> what your outfit did. That's perfectly sensible, not the same at all as
> filling five times with liquid propane.
>
> Yrs,
> d
>
> On Wed, Mar 22, 2017 at 6:45 PM, Neil2 <vidublu@gmail.com> wrote:
>
> > I'd never visit that place again. Insane there are places operating like
> > that (5x).
> >
> > On Wed, Mar 22, 2017 at 10:52 AM, David McNeely <davmcneely40@gmail.com>
> > wrote:
> >
> > > Hmmm..... . I bought a new GoWesty tank and had it installed
> locally. I
> > > asked the mechanic where to have it purged, and he recommended a local
> RV
> > > dealer. I took it there. I am certain that the place did not use a
> > "purge
> > > kit." The person who first was going to do it said that he had to
> simply
> > > fill it, empty it, and refill it again. I was dubious, and asked the
> > shop
> > > foreman, who said no, it required five times. So, that is what they
> did.
> > > There was no portable tank involved.
> > >
> > > I have not used the propane since. I plan to use it in two weeks from
> > > now. What do I do to make sure the tank is safe? This was not a small
> > > expenditure, but I did it for safety. Now I am not confident that it
> is
> > > safe.
> > >
> > > mcneely
> > >
> > > On Wed, Mar 22, 2017 at 10:32 AM, Stuart MacMillan <
> stuartmacm@gmail.com
> > >
> > > wrote:
> > >
> > > > I've been using a Worthington 3lb tank for a couple of years. I love
> > it,
> > > > and it fits nicely under the seat. I now carry one 1lb bottle for
> when
> > it
> > > > runs out, but if you weigh it after use, you can usually avoid
> running
> > > out.
> > > >
> > > > Just take it to a propane filler, it purges with the fill. They open
> > the
> > > > release valve and air is pushed out and replaced with liquid propane
> > and
> > > > vapor. I don't think you'll be able to fill it yourself since modern
> > auto
> > > > stop portable tanks do not allow rapid flow from the valve, and I
> also
> > > > think the auto stop float will shut off the tank when upside down.
> > > Besides,
> > > > it's not a good idea, and not even worth the trouble even if you
> could.
> > > >
> > > > Those safety features were designed to protect us from ourselves!
> > > >
> > > > Stuart
> > > >
> > > > -----Original Message-----
> > > > From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On
> > Behalf
> > > > Of Neil2
> > > > Sent: Wednesday, March 22, 2017 10:02 AM
> > > > To: vanagon@GERRY.VANAGON.COM
> > > > Subject: Re: advice on new propane tank
> > > >
> > > > David,
> > > >
> > > > Please tell the kids on FB since this could save a Vanagon, er a kids
> > > life
> > > > I mean!
> > > >
> > > > On Wed, Mar 22, 2017 at 6:09 AM, David Beierl <dbeierl@attglobal.net
> >
> > > > wrote:
> > > >
> > > > > They're full of air to start. That's too lean to burn. In use
> > > > > they're full of propane which is too rich to burn. You have to
> get a
> > > > > new tank past the point of containing an explosive mixture before
> you
> > > > > can use it or the first time you light something it could flash
> back
> > > > > through the lines and blow the tank apart.
> > > > >
> > > > > Yrs,
> > > > > d
> > > > >
> > > > > On Wed, Mar 22, 2017 at 6:36 AM, Roman Haag <romanhaag@ymail.com>
> > > wrote:
> > > > >
> > > > > > So a new tank needs to be purged? I did not know this.
> > > > > >
> > > > > > Sent from someone's plumbing
> > > > > >
> > > > > >
> > > > > > > On Mar 22, 2017, at 01:37, David Beierl <dbeierl@ATTGLOBAL.NET
> >
> > > > wrote:
> > > > > > >
> > > > > > > Off the cuff -- I'd take it to any propane place to purge.
> > During
> > > > > > purging
> > > > > > > at some point there will be an explosive mixture in the tank,
> you
> > > > > > > don't want to be around if it finds a spark.
> > > > > > >
> > > > > > > Yrs,
> > > > > > > d
> > > > > > >
> > > > > > >> On Tue, Mar 21, 2017 at 9:32 PM, gary hradek <
> hradek@yahoo.com>
> > > > > wrote:
> > > > > > >>
> > > > > > >>
> > > > > > >> I just bought a Worthington Pro Grade 4.25 lb. Empty Propane
> > Tank
> > > > from
> > > > > > >> Home Depot to use with my Colemanstove. The 1 pound
> cylinders
> > > are
> > > > > > >> nowclose to 8 dollars a piece. I was goingto fill it from
> the
> > 20
> > > > > pound
> > > > > > >> tank but they say something about purging it. Can I just
> fill
> > > and
> > > > > > empty
> > > > > > >> it a few timeswith propane vapor before trying to fill it with
> > > > > > >> the
> > > > > > liquid
> > > > > > >> by inverting the 20pound tank? I am guessing there is
> acharge
> > to
> > > > > have
> > > > > > it
> > > > > > >> purged somewhere?
> > > > > > >>
> > > > > > >> Gary
> > > > > > >>
> > > > > > >>
> > > > > >
> > > > >
> > > >
> > > >
> > > >
> > > > --
> > > > Neil2
> > > > '82 Diesel Westfalia (Ducky)
> > > > '86 Vanagon (SaVannah)
> > > > '08 170" 2500 Mega Roof Sprinter (Moby)
> > > > '90 Westfalia Subagon (SaL)
> > > > Fulltiming since August 2008
> > > > Nunquam Pendite Divendium
> > > >
> > >
> >
> >
> >
> > --
> > Neil2
> > '82 Diesel Westfalia (Ducky)
> > '86 Vanagon (SaVannah)
> > '08 170" 2500 Mega Roof Sprinter (Moby)
> > '90 Westfalia Subagon (SaL)
> > Fulltiming since August 2008
> > Nunquam Pendite Divendium
> >
>
--
Brett in Portland, OR
"Albert" '82 VanaFox I4 Riviera
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