<HTML>Arnold,
Sounds like a neet project. I have been wondering how well one of Mike Brown's engines works. Please keep us posted.
As for solid fuel furnaces, there are a numerity of designs for automated fuel induction on the market. Almost all of them are designed to use wood chips, corn cob chips, wood pellets or corn cernels. Most of them use a underfed design, utilizing a auger to feed the fuel from the hopper to the burner. Then they admit the combustion air above the fire from the side. There are also many designs that drop the fuel via an auger onto the top of the fire and admit the air through the fire itself.
I think that a simple viable design would be to have an underfed auger driven design with manual or automatic operation of the auger. They can be purchased from Grainger or any of those establishments.
One fully automated system that looks to be very simple and is applied to industrial boilers and home heating systems is the Messersmith.
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www.burnchips.com]
There design is very simple and availiable. They may even be willing to design a burner system for your aplication. They use electronic control of the auger and fan system so it is completely automated.
For visualization of a system that I think would work, take a basketball and cut the top 1/5 of the ball off. Then cut a hole in the bottem of it to feed the fuel into with the auger. Make another small hole in the side of it that would direct the air around the inside wall horizontally around the ball. So the fuel would come in through the bottem, the air through the side and the hot gases and some radiation would exit through the top hole into the water tube area.
The spherical design of the furnace would allow one to operate the aparatus at high angles without worrying about the fire being disturbed in the boiler and literly hitting the water tubes.
As for ash removal, I would use an excess of air induction(forced) that would shoot the ashes and some cinders into a standard centrifugal ash collector at the exit of the exhaust stack. This would meen that there would be a minimum of ash to take out the the furnace when cleaning was done, but the water tubes would get dirty and need regualr cleansing.
Since weight doesn't matter on a tractor one could construct the furnace from two halves of cement shells and coat the inside of them with furnace cement and possibly fire brick to protect the cement from the intense heat. This a centrifugal fan and a auger with either a hand crank or a geared down power coming from the main engine or a small electric motor also geared way down would be all of the materials needed for the furnace. Note that there is no firegrate with an underfed method that uses combustion air that is admited on top of the fire. However there would most likely need to be a door so that one could inspect the furnace and clean it out every now and then.
Please, tell me if you think it is a viable idea.
Caleb Ramsby</HTML>