"Roger" wrote

I didn't think they could sell them without them. (caps)
Tanks have had to have that provision for years. OTOH there are a lot
of lost caps floating around... some where.

I *think* tanks with a guard around the valve, (so a blow sideways can not
knock off the valve) are still legal. I have an old acetylene tank like
that.

If the Acetylene tank were laying down I think I'd have a problem with
all the acetone coming out the torch tip.

Correct. Acetylene is actually dissolved in acetone, so as you use the gas
and the pressure gets lower, the acetylene "evaporates" or "comes out of
solution" to come out the tip as a gas. If the tank were on its side, you
would get acetone coming out of the tip.

There is also another difference in the tanks, between Oxy and Acety.

The Oxy tank is a big open container on the inside. The Acety. is like a
metal honeycomb, or metal sponge, with the acetylene and acetone in the
little cells. I think it has something to do with providing maximum surface
area of the liquid, allowing the acetylene to come out of solution at rapid
flow rates.
--
Jim in NC