[Stoves] Insulation and stove life

[Bob Tingleff]

Belonio's TLUD design calls for an insulated gasifier reactor, with the
inner cylinder being 20 gauge stainless, though Paul O's version is not
insulated. And Rocket stoves are insulated.  So I'm surprised to see the
comments below pass without any discussion. I wonder if Belonio's rice husk
gasifier stoves have longevity problems.

Bob Tingleff

 On Fri, 31 May 2013 18:39:54 -0400,"Crispin
Pemberton-Pigott" <crispinpigott at gmail.com
<http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org>>
wrote:

>*If you use metal, do not put insulation behind it. You must either waste a bit of heat or use it for preheating air. *
This is very important, I think I once saw it posted that the
temperature of the metal  for purposes of longevity was as if it was
the average temperature of the two surfaces. As stainless is a worse
conductor than mild steel it follows that one should use the thinnest
sheet needed to prevent the inner surface getting too hot.

We had a customer who would not understand this, he was firing an oil
burner into a fire tube heat exchanger through a tube, this tube
burned out every few months and he would replace it with a thicker
tube, which burned out faster. What we recommended, and he ignored,
was to make the tube thin and bleed some excess air over it into the
heat exchanger.

In the past we talked about a "wash" of clay suspended in milk to
occasionally paint the steel surface exposed to combustion, I tried it
but as I don't run stoves for long enough never came to a conclusion.

I have a cast iron Jotul stove here which is 30 years old and hasn't
burned through, though there have been problems at the plate joints.

AJH
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