On 6/27/2010 8:47 PM, Ned Simmons wrote:

(...)

There may be more stress on the welds than you thought, but it's
unlikely EA's 5 psi came anywhere close to overstressing them. The
vapor pressure of gasoline at room temp varies from 4 to almost 10 psi
at 70F, depending on the formulation. So the pressure in a sealed drum
containing gasoline could easily be twice EA's 5 psi.

Doubtlessly, *some* newsgroup'ers will misinterpret this thread
to mean that it is OK to pressurize a 55 ggl drum ca. 5 PSIG
so that they dispense via a valve the output side. (Try precisely
metering a fluid using a compressible gas sometime.)

When in reality, that is exactly the corner you do not want to
be in. I know that in electronics, we look 'hard and long' at
a potential design solution that 'burns up safety margin'.

Instead, we can normally accomplish all the design goals without
decreasing safety or reliability.

In this case, a barrel pump or 'vacuuum-start siphon' are both
inexpensive, effective ways to safely handle liquids in these
large drums.

That's my story and I'm stick'n to it.

--Winston