Jim Stewart wrote:

pyotr filipivich wrote:

I missed the staff meeting but the minutes show "Glenn"
wrote back on Sat, 22 Jan 2005 16:15:27 -0800 in
rec.crafts.metalworking :

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.



For the "Rube Goldbergs" among us, it shouldn't be "too
difficult" to
rig a water quench on the steam tank. That is, when the "Oh ****"
pressure valve cuts loose, it trips water reserve, which floods
around the
boiler, which "should" soak up heat from the boiler, and hopefully lower
the temp enough to keep the superheated water from trying to become
steam.
Or just lower it back to "really hot water".

What comes to mind is a kind of jacket around the boiler, with at
least
an equal capacity to the boiler. Normally it is empty, but to shut
things
down, you dump water into it and let nature take its course. Hmmm,
now I'm
going to be up all night pondering this.


Even better might be a "pressurizer" tank such is
used with nuclear reactors. A large tank of hot
water located above the boiler and at a slightly
higher pressure. It would supply makeup water at
the same rate as is being consumed by steam
production.

Then to avoid the pressurizer tank having a problem, you would want an
even higher pressure tank plumbed to supply makeup water to your
pressurizer tank...I think this needs further consideration.

Steve