On 6/24/2010 7:01 AM, Ned Simmons wrote:
On Thu, 24 Jun 2010 00:29:27 -0500, Don Foreman
wrote:

On Wed, 23 Jun 2010 22:07:50 -0700,
wrote:



Hokay but the drum still has 2.8 x the seam length of the jerrycan.

That's a good thing. The total force is divided by the length of the
seam.

More is really better?

I thought the seams represented the weakest link.

I stumbled across a claim that the flat top and bottom
of the drum go noticeably convex at only 5 PSIG.

5 PSIG is about 11.5 feet of water head. Head necessary to get the
stuff out of the drum is only 35" or 1.26 PSIG. "Noticibly convex" is
markedly different from "BOOM" so about 0.252 NC (Noticably Convex)
seems safe enough to me.

And the 35" of head represents the hydrostatic pressure that the
bottom head sees anyway when the drum is full. Add a few more inches
to get over the rim of the drum, and a bit more to get a reasonable
flow thru the spout, and I don't see a problem, conceptually anyway.
The real challenge is in making damn sure the drum is never
over-presssurized.

A failed gas regulator shouldn't cause anything worse than
minor disappointment. I am lazy by nature and would be
likely to leave the air connected. This approach would
make me nervous.


I could imagine using a tall standpipe of generous diameter as a
pressure relief. Not that I'd recommend anything as crazy as
pressurizing a 55 gallon drum.g

When a drum pump fails, you get no product.
When a regulator fails, you get product *everywhere*.

--Winston