I hesitate to jump in here as my knowledge of the subject is limited to
reading, but IIRC the problem lies in the superheated water in the
container. The pressure allows the water to be heated to well above boiling
point at atmospheric pressure. When you release the pressure as in opening
the steamcleaner valve, all the water can now turn to steam very rapidly.
If your popoff valve does not have sufficient capacity to dump the excess
pressure fast enough the vessel can become overpressured and turn into a
bomb. Seems there was also a greater problem as the water level gets down,
the flash over can occure more rapidly.
Other than that I am all ready to go fire up the crab cooker and stick a
propane tank full of water on it to see how well it works
Glenn
"Ian Stirling" wrote in message
...
Grant Erwin wrote:
larry g wrote:

One of the model engineering magazines, HSM I think, had an letter from
a
boiler inspector about this very subject. He went on about pressure
vessels
and heated pressure vessels being very different. In the end it was no
way
in hell should anyone do this. I'm sorry I can't quote the article as I
have been going through a lot of the old magazines that I have just
acquired.

Hmm. Often when someone from an industry whose revenue source depends on
scarcity says "oh no you surely cannot do that" what it really means is
"oh my if everyone did that I'd be out of work". I vaguely remember the
letter, probably was HSM. I'd welcome it if anyone knows which -- since
1982
there have been over 135 issues, that's a LOT of reading.

Practically all the heated boiler/steam legislation is there because
people have regularly killed themselves with things they thought would
be fine.