"Ned Simmons" wrote in message
news
On Thu, 24 Jun 2010 00:29:27 -0500, Don Foreman
wrote:

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


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.

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

If I were to do this, I would make it so I would only hand-apply a rubber
tipped air nozzle, and eventually put a relief valve on, as well. And just
crack the ball valve on the compressor, to limit air flow.

I do something similar with a grease gun and motors.
I actually remove the grease fitting, and use a rubber air-hose-type
tip ( from a grease gun "kit" from HD, iirc), to grease the bearings.
Baldor told me to be careful about grease fittings/guns on motors, cuz they
siad it's relatively easy to rupture seals. So I use this method, where it
becomes very evident when things are packed.

Automotive joints are different, I would imagine.

So applying the air "by hand" will hopefully afford a similar safety hedge.
Unless I fall asleep.....
--
EA



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Ned Simmons