The chart says that if I heat water under 50# pressure the steam temperature wil be almost 300 degrees. If I were to release that same steam into a non pressurized cylinder as in steaming a piece of wood and it had a small vent on one end what temperature could I expect to reach in that cyl? Would it be a dry heat? or a moist heat?
Another related question, would I do better building a type of sauna with hot rocks and just spray water over the rocks to keep the steam up. I am looking to bring the temperature of the wood up to about 260 degrees or so for an extended period of time maybe 4 hours at the most.
Heat it in propylene glycol instead (bp. 370 F). It’s pretty cheap; used in solar panels. Non-toxic; also miscible with water.
You’re building 50 psi of steam head in a little boiler, then suddenly venting it into another chamber that’s vented to atmosphere, right?
We don’t know enough to predict the temperature. If the second chamber is very small compared to the boiler, you would replace most of the air in it with steam. I’m not clever enough at this hour to say what the temperature would be but it would be below 300, and there would be condensation so you would have a moist heat.
If you are doing this in a steady state, meaning you release the steam through an adjustable valve that maintains the 50 psi back pressure, then you would be in a similar situation.
In both these situations there is some temperature that would be the limiting temperature you could reach, if you had perfect insulation and maybe met other conditions, and I’m not clever enough to know if that temperature is 300 or 212 or somewhere between. Maybe if the coffee works…
If the second chamber was very large compared to the boiler, the temperature could be only a little above room temperature. It would still be moist.
The sauna thing sounds like it adds a lot of extraneous brouhaha.
You want to keep the wood at 260 for four hours, but, do you want it wet or dry or in between?
I was just trying to avoid scorching, Thinking about it if the wood did reach 260 it would be very very dry at that point.
If you control the temperature to no more than around 248 F (120 C) then the wood shouldn’t scorch at all, I think. That’s according to the table at:
http://www.tcforensic.com.au/docs/article10.html
And, yes, at 260 F and atmospheric pressure, the wood shouldn’t have any wetness to it at all.
Assume two chambers. One the boiler the other the Sauna? Boiler pressure set point.
If you have the boiler firing at set point. Everything cold main steam valve closed. Sauna at room temperature.
As the main steam valve is opened 300 degree will enter the sauna. Assuming the the boiler has a dry pipe. The steam will quickly cool to 212 and begin to condensate. If the boiler can keep up with the load the sauna will begin to heat up. The temperature of the sauna will depend on how much heat is lost from the sauna vs how much steam can be added.