chemrox - 21-4-2008 at 22:15
My lab is in what was an old house that was converted to offices years ago. I have done and continue making the changes to the former kitchen as the
lab. The exhaust fan is being added to a window space. Looking for a suitable location for my eyewash station I ran across the extra water heater.
It occupies about 18-24 cubic feet under one of my counters. There is a central gas fired water heater so this one just takes up space. I wonder if
I could make it into a steam plant or locate a compressor there. If anyone knows about making a water heater into a dry steam source I'd like to
hear.
Mr. Wizard - 21-4-2008 at 22:30
Water heaters generally have a TP , or temperature pressure relief valve on them to keep them from delivering 'dry steam' . Most water heaters are not
built to run dry. Electric heating elements will burn up within seconds if the water isn't pulling the heat off of them. Gas units will overheat and
spall off the porcelain liner. It may even burn through the metal if run dry. You will need to keep water over the heat input area. Are you looking
for pressurized steam or just steam without water mixed in, or steam hotter than 100C?
chemrox - 22-4-2008 at 18:06
steam without water. at 100* would be fine.
Mr. Wizard - 23-4-2008 at 11:14
OK you are basically talking about wet steam at atmospheric pressure. How much steam do you want? Are you trying to generate it for a lab function or
run a machine or just not sure yet? To make it work, you will have to keep water over the heat source. This will involve a float mechanism to insure
you always have water. The float does not have to be inside the tank, or even be heated. It can connect with the bottom of the tank and can equalize
by gravity, as long as the opening of the tank is at atmospheric pressure, or at least the same as the float tank. Restricting the opening will raise
the pressure inside the tank and the temperature. The TP valve will fail in this mode, as it is designed to 'give it up' below 100C. You might as
well remove it, or get one that will work at over 100C, which would be the best and safest. I'm not sure how to advise you on temperature regulation.
I doubt the existing thermostat will go that high, but who knows? Just be sure not to seal up the tank and apply heat. They have a name for it,
BLEVE. Boiling Liquid Expanding Vapor Explosion. An exploding water boiler will really make trash out of a building. The whole idea sounds a little
dangerous. I don't like big heated water tanks, not designed to be used as boilers. My 2 cents worth. This setup would need constant supervision.