Date: Thu, 4 Oct 2012 09:21:55 -0700
Reply-To: Stuart MacMillan <stuartmacm@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Stuart MacMillan <stuartmacm@GMAIL.COM>
Subject: Re: Propane Tank question
In-Reply-To: <1349320368.15830.YahooMailClassic@web121502.mail.ne1.yahoo.com>
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As said, the concept is to purge with vapor at a low pressure four times
(not add any liquid propane, which has a vapor pressure of 130 psi):
http://www.ehow.com/how_5998703_purge-propane-tank.html You need one of
these and another full tank to do this:
http://gas-flo.com/products2.html?p_id=78# Find a propane supplier who has
one.
On small tanks like ours you can vent the gasses for a few seconds from the
bleed valve or shutoff to purge them, but that is hazardous, and refill
stations won't do it, of course. Usually you just spend several minutes
trying to light the stove! Voila, when it lights you are purged.
Stuart
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
David Vickery
Sent: Wednesday, October 03, 2012 8:13 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: Propane Tank question
You're right Dennis (and Mike). Unless the tank is opened it should not get
air inside. My bad.
Basically what I said was wrong. I spent a little while educating myself
about purging propane tanks. Seems like the the biggest real life problems
from not purging are air/lp mix that doesn't burn well, regulatgor freeze up
from the water vapor in the tank, odorant fade and over pressurization
(which will go out the relief valve).
The interesting thing I learned is they can't purge a tank at the fill
station, it needs to be purged with LP vapor not liquid so it needs
additional hookups besides what they have at the pump. I had a good LP
service station do it that way once. Oh well.
And I have gotten away with not purging a couple tanks I replaced valves on,
but I assume after several empty/fill cycles, they were purged.
Feel free to correct me if I'm wrong.
--- On Wed, 10/3/12, Dennis Haynes <d23haynes57@HOTMAIL.COM> wrote:
> From: Dennis Haynes <d23haynes57@HOTMAIL.COM>
> Subject: Re: Propane Tank question
> To: vanagon@GERRY.VANAGON.COM
> Date: Wednesday, October 3, 2012, 6:57 PMYou Actually when liquid
> propane come out of the bleeder the tank is only 80% full with the
> required vapor space remaining above the liquid. In normal use the
> tank is always pressurized and even if allowed to go empty very little
> outside air should be getting in. As compared to a new tank that has
> never been filed or may even have some water left in it from testing.
>
> Dennis
>
> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com]
> On Behalf Of
> David Vickery
> Sent: Wednesday, October 03, 2012 4:30 PM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Re: Propane Tank question
>
> I think people are making too much out of purging a tank. When it
> runs out of propane as they often do, it is filled with air.
> When the bleeder is
> opened while filling the air is expelled out the bleeder. When liquid
> propane starts coming out the bleeder, it is full.
>
> --- On Wed, 10/3/12, Mike S <mikes@FLATSURFACE.COM>
> wrote:
>
> > From: Mike S <mikes@FLATSURFACE.COM>
> > Subject: Re: Propane Tank question
> > To: vanagon@GERRY.VANAGON.COM
> > Date: Wednesday, October 3, 2012, 12:15 PM On 10/3/2012
> 11:32 AM,
> > Stuart MacMillan wrote:
> > > Problems like this are maddening! Bad auto stop
> > valve or bleed valve that
> > > doesn't vent are the only things that can prevent
> > filling.
> >
> > It's more likely that the tank simply needs to be
> purged of air, as
> > already mentioned.
> >
> > When the tank has nothing but propane in it, it can be
> easily filled.
> > Pumping liquid propane in increases the pressure, and
> the existing
> > propane gas in the tank turns to liquid, making room.
> For a tank at
> > 80F, that pressure is about 130 psi.
> >
> > If you try to fill a tank which has air in it, the air
> simply
> > compresses, and pressure goes up. New tanks are often
> shipped with
> > compressed air in them, so you can't push much propane
> in before the
> > pressure gets too great to be able to pump more.
> >
> > Hence, the need to purge the air from the tank before
> first use.
> >
>
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