iandol on tue 29 feb 00
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It seems kind of an accepted general rule that when firing with =
propanetanks,
they =22freeze up=22 but does anybody know why? Do the tanks lose pressure =
as
they're emptying or is that just a consequence of another phenomenon? =
Besides
shaking the tank and pouring hot water over it, are there any other ways of
deterring it? Thanks for any help.
LPG tanks appear to freeze up because they cool down as the LPG evaporates. =
This
causes the temperature of the bottle to fall. Water condenses on the outside=
of
the tank and will eventually freeze to ice. I doubt if the liquid inside
freezes. The freezing point of Propane is minus 187.7 Celsius, of Butane =
minus
138.4 Celsius, very chilly. Heat from the environment keeps the stuff
evaporating even under pressure. As you evaporate gas more quickly to supply=
the
greed of the kiln for more heat as its temperature increases, more heat is
needed by the bottle to keep the pressure up because cold liquids do not
evaporate as quickly as warm liquids. The faster you pull out the gas, the
colder the tank gets.
How to overcome this.
1 Just keep a cold hose going over the tank. 2 Put a blower heater to warm =
the
tank. 3 Gang two or more portable bottles together on one manifold and run =
both
open. 4 Install a big capacity tank, like 1000 or 5000kg.5 Stand the bottle
where it gets radiation from the kiln, but be sure you have no leaks in your
system.
Just as a matter of interest, how many Clayarters who use gas check their =
unions
when they connect a fresh bottle to find out if they have a perfect seal? =
Even a
few bubbles can lead to an explosive mixture at floor level over a period of
time.
Ivor. Still inquisitive
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