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/B00H
> 2L7LWA/ref=sr_1_1?ie=UTF8&qid=1445356075&sr=8-1&keywords=Propane+Tempo
> 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--.htm
> 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