Easy easy. Just have gas stream from the nozzle without
a flame. It gets cold... The tank in your hands is soaking
heat from your hands or gloves... Sun lights and a long list.

Martin

On 10/25/2015 2:15 AM, John B. wrote:
On Sat, 24 Oct 2015 10:11:09 -0400, Bob Engelhardt
wrote:

On 10/23/2015 11:41 PM, Bob Engelhardt wrote:
...
if you put the torch on a _warm_ tank and let it sit in the cold, the
gas in the tank would have a higher vapor pressure than gas in the torch
chamber and you would get transfer. Vaporization in the tank and
condensation in the torch. It's possible.

The Engineering Toolbox* gives the vapor pressure of propane at 70F as
130 psia (+_) and at 0f as 40 psia.

So with a warm tank at 70 & a cold torch at 0, there would be 90 psi
difference pushing propane gas into the (off/closed) torch. The warm
gas will quickly fill the chamber and equalize the pressure, but that
pressure will be higher than the vapor pressure of the cold chamber and
the propane will start condensing.

Equilibrium will reached when the chamber and tank temperatures are the
same. The tank will cool from vaporizing liquid (and from being in 0F
air) and the torch will warm from condensing vapor. How much propane
that will take depends on too many things for me to even guess at, but
the end result will be liquid propane in the torch chamber.

Bob

* - http://www.engineeringtoolbox.com/pr...re-d_1020.html

The question might be raised about how do you arrive at a 70 degree(F)
tank and a 0 degree torch?
:-)
--
cheers,

John B.