I'm no physicist, but...

I believe that as long as the vapor pressure inside of the 2 containers is
sufficient to keep the propane in a liquid state then the liquid will flow
downhill into the westy tank.  There will still be gaseous propane in the
small tank.  Once the valve is opened to the stove, the system is no
longer static and becomes dynamic.  The vapor pressure will want to
decrease to supply the fuel to the burners, but as the vapor pressure
decreases the liquid propane starts to boil and release more vapor to try
and keep the pressure constant.  Once all of the liquid boils off and only
gas remains, the pressure will decrease until the tanks are empty.

At least that is my understanding.

Pat

From:   Stuart MacMillan <stuartmacm@GMAIL.COM>
To:     vanagon@GERRY.VANAGON.COM
Date:   10/20/2015 11:03 AM
Subject:        Re: Propane refill adaptor
Sent by:        Vanagon Mailing List <vanagon@gerry.vanagon.com>

Right, but I don't think it all will go in. Some liquid may be left when
pressure equalizes. Maybe someone who has one can tell us if there is
still some propane sloshing around if the canister is removed before using
any appliances. If not, I'd put another one on and see how much of it goes
in, and repeat until no more goes in and then leave the last one
connected.

Stuart

-----Original Message-----
From: mcneely4@cox.net [mailto:mcneely4@cox.net]
Sent: Tuesday, October 20, 2015 10:57 AM
To: vanagon@GERRY.VANAGON.COM; Stuart MacMillan
Subject: RE: Propane refill adaptor

Ok, I can see that.  But the brief instructions online say to "pour" the
canister contents into the tank.  It looks like they are saying to do
that, remove the canister, then use the appliance from the tank, canister
disconnected.  One of our list vendors offers an "extend a stay" kit that
does what you suggest.  This does not appear to be the same thing. mcneely

---- Stuart MacMillan <stuartmacm@gmail.com> wrote:
> You are right about the equal pressure, but only a small amount of the
liquid propane in the canister will evaporate into the empty tank to
equalize the pressure.  Liquid propane will remain in the canister until
it all vaporizes into the tank with use.
>
> Think of the empty tank as a big fat pipe extension on the canister. It
doesn't take much liquid propane to vaporize and pressurize that "pipe."
It's the same as using the last small pool of propane in the bottom of the
nearly empty tank, but the pool is now in the canister.
>
> Stuart
>
>
>
> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On
> Behalf Of Dave Mcneely
> Sent: Tuesday, October 20, 2015 9:52 AM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Re: Propane refill adaptor
>
> Well, I'm no engineer, nor can I claim that my physics is always on
> the money.  But, I would assume the  assembly would only work up to
> the point that the pressure in the two containers was equalized,
> leaving propane in the canister, and not getting much into the tank.
> But who am I do say?  I realize that the tank is a lot bigger than the
> canister.  Don't those cans hold one pound?  mcneely
>
> ---- Karl Ploessl <karl.ploessl@GMAIL.COM> wrote:
> > http://www.amazon.com/Propane-Temporary-Refill-Adapter-Eurovan/dp/B0
> > 0H
> > 2L7LWA/ref=sr_1_1?ie=UTF8&qid=1445356075&sr=8-1&keywords=Propane+Tem
> > po
> > rary+Refill+Adapter+for+Westy+%26+Eurovan
> >
> > http://www.thesamba.com/vw/classifieds/detail.php?id=1567630%5B/url%
> > 5D
> >
> > http://www.thesamba.com/vw/forum/archive/index.php/o-t--t-612317--.h
> > tm
> > l
> >
> > On Tue, Oct 20, 2015 at 11:29 AM, Rocket J Squirrel <
> > camping.elliott@gmail.com> wrote:
> >
> > > Link?
> > >
> > > --
> > > Jack "Rocket j Squirrel" Elliott
> > > 1984 Westfalia, auto trans,
> > > Bend, Ore.
> > >
> > >
> > > On 10/20/2015 08:17 AM, Dennis Jowell wrote:
> > >
> > >> Has anyone used this "Propane Temporary Refill Adapter for Westy
> > >> & Eurovan"
> > >> from Monster Industries LLC sold by Amazon.com?
> > >>   I wanted to make sure not to run out of propane and thought
> > >> this might work.
> > >> Any thoughts?
> > >>
> > >>
> > >> Dennis Jowell
> > >> Scotch Hollow Farm
> > >> Newbury, Vermont
> > >> 1988"Westy GL
> > >>
> > >>
>
> --
> David McNeely
>

--
David McNeely