On Thu, 27 Jan 2005 10:06:13 +1100, "Tom Miller"
wrote:

The whole boiler idea is a bad one. They store substantial amounts of
energy,and even a small one would destroy the average garage, not to mention
anyone standing nearby. There are codes to design boilers.( I think the
American on is ASME section VII) You might read that before you go too far
with your design. Industrial boilers have two safety valves and a control
system to keep the pressure constant as well as a pressure switch which
shuts off the gas or oil supply in the event of the boiler going over its
safe operating pressure. The "Scram" system would probably CAUSE an
explosion as the sudden thermal stresses would cause a fracture somewhere
that would propagate at the speed of sound in steel.


Tom

"pyotr filipivich" wrote in message
.. .
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.


--
pyotr filipivich.
as an explaination for the decline in the US's tech edge, James
Niccol wrote "It used to be that the USA was pretty good at
producing stuff teenaged boys could lose a finger or two playing with."

All this talk about boilers is why I decided not to make a steam
engine. The boilers just require too much vigilance. Which I'm not
prepared to be. Vigilant, that is.
ERS