firebox design

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leon

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With the issues of smoke from Outdoor Wood Boilers becoming
an even larger issue these days, perhaps the issue of fire box
design should be examined further.

Taking the pot bellied wood and coal stoves as an example
outdoor boilers could benefit from their design.

The combustion chamber would not have to be vertical but it
would benefit from being verticle if it was 24 inches in diameter or larger
and had an underfed combustion air path like the pot bellied stoves.

AN outdoor wood boiler could have 1/4 inch boiler plate and have a circular wood and
coal combustion chamber 24-36 inches in diameter built with 1/2 inch boiler plate
and rolled into form then welded to seal the two edges.

The potential for an atmosperic draft system with thermostat controlled set of draft
doors for both the underfire and overfire draft with a vertical combustion chamber
lends simplicity to itself because of the bottom up burn design and a smaller
combustion chamber to create heat faster with less smoke by having a circular
vertical firebox in my opinion.


The rotary grate operated by a stoker motor would be slowed to a crawl
speed and permit long cycles for the wood fire to combust or create a blue flame
over the coal bed before cranking the worm gear to rotate the circular grate.

One could employ a coal stoker in the same manner with an outdoor boiler using
the rotary grates I would think as well with good results when a good wood fire
is created before the coal burn in the boiler.

The coal stoker would be employed using a delivery system that would pour the
coal over the exisiting fire in small amounts when operating where the pea or
rice coal would be carried along with the circular grates rotation under the fire.

The risk of a coal fire would be nearly eliminated because the coal is being fed over
the edge of the combustion chamber by the auger OR the boiler could be hand fired
with chestnut coal and banked for the night with pea coal or firewood as well.


A heat exchanger built like the fire tube system in steam powered locomotives
would be an easy way to extract heat and smoke from the burn and provide lots
of heat to the water stored in the boiler.


The OWB could use the circular wood and coal grates that are cranked with a
worm to rotate the grates and then the fine ashes would drop into a collection basket
as it done with coal and wood pellet stokers.

The coal stoker gearboxes are designed to allow the end user to regulate the
speed of the gearboxes so the grates would be rotated at a very slow rate
which would permit near complete combustion of the wood or coal.


Round fireboxes are round for a reason and have a firebrick lined surface for the same
reason as they concentrate the heat and it aids in combustion



I really think that these manufacturers should look at this as an alternative to the current
methodology simply because the pot bellies do work and have worked and a bit more
design would improve both the image and efficiency of an OWB in general.



Something to think about in the scheme of things.
 
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