Marshall-Henderson Heat treat kiln

[armechanic]

Does anyone know anything about these ?  I think they are older kilns and were bought out. (Nyle ?) I am wondering if parts are still available.?

[GeneWengert-WoodDoc]

I do believe that calling these a kiln is incorrect.  They are used or were used to provide a large amount of heat (1.2 million btu per hour) at 180 or hotter in order to reach 133 F in pallets within a couple of hours.  They used direct fired burners.  They did not control humidity.  No vents.  I believe there were no fans like what we use in lumber drying, but the direct fired burners had fans.  The walls were uninsulated.

They have a burner, walls, roof and doors with few moving parts.

[armechanic]

I am looking to heat treat firewood, so this might work. However, I don't like the open burners so much. Thanks for the reply.

[GeneWengert-WoodDoc]

This unit was designed for pallets which are assembled.  So, there is a lot of air space and not much wood in a load.  A load of split firewood will have a lot more wood and so will take longer to heat thoroughly.  Longer time means more inefficiency when heating without insulation in the floor, walls and roof. 

You need to make sure you have a cheap source of fuel (natural gas) and that the added value of heat-treated firewood is large enough to cover the cost; most of the cost will be fuel. 

We do make insulated kilns that go to 240F, so I do wonder if you might make you own chamber, or consider modification of the MH heat-treater chamber. 

Direct-fired burners, when used for kilns, do have safety devices to avoid fire risks.  Of course, natUral gas has less risk than wood-fuel, direct-fired. I  A plenum system, like we use in a house, is possible but not efficient for high heating rates.  So, that is why many kilns use steam boilers which are quite efficient in transferring heat from wood chips, sawdust, etc. to water, to steam, to fin pipes and to hot air in the kiln.