evaporator insulation

[tessiersfarm]

I have a homemade wood fired evaporator 27"x4'. I am thinking of insulating the outside with mineral wool fiber insulation to improve the boiling rate. Has anyone done this? And did it help. Thanks in advance.

[Fred Henderson]

As long as it won't burn,melt or scourch any thing that you can do to insulate will help.

[Uncle Tucker]

I think the metal would get to hot and melt. I would think insulate inside. Maybe with bricks.

[tessiersfarm]

The Arch is 1/4" Boiler Plate and the wool is rated for 1900 F. How hot does the arch get?

[maple flats]

I also think it would get too hot and at least warp even 1/4" plate. Bricking the inside is the way evaporators are best insulated if wood fired, for oil or gas you use brick, or blanket or a few other choices, but brick can take the wood damage potential. As far as the question about how hot it gets, the flame in a roaring wood fire where as much air as needed is forced in the temp can exceed what you might think. I do not have a number but in some house fires you hear of things melting big time. A bowling Alley burned last winter in my town and the I beams and H beams were a twisted mess after the fire and they were over 1/2" thick on the main ones, the heat softened them to allow extreme twisting and distortion and this fire was not insulation on the outside to hold the heat against the steel. The fire was out in about 3 hours if I recall correctly, you will be burning much longer than that. I do not know what temp boiler plate can take but it is likely rated for a safe working temp of maybe 400-500 degrees for extended times, consider, boilers even in high pressure steam are still down under that range. What keeps the boiler plate intact now is that 1 side can dissapate the heat.

[lpakiz]

I have an arch made from 8 inch bridge I-beam. To insulate, I used old aluminum signs and bolted them to the outside of the I-beam, then used fiberglass insulation to insulate outside of that. It does work but the insulation is about shot after 2 years. Also, it will burn the paper off where ever there is not that layer of aluminum sign protecting the insulation.. I suspect that without the initial layer of aluminum, the fiberglass would burn out after several hours of hot fire..

[Fred Henderson]

Put the insulation on the inside then put brick over that.