The Warm Heart FC Trough

The Warm Heart FC Trough

The Warm Heart team has been developing a new type of flame cap / flame curtain (FC) biochar production unit. These are FC Trough units, which are defined as above ground FC units with a non-square, rectangular top aspect.
The general design was developed as a result of considering the easiest low tech way to pyrolyze a great variety of the feedstock types available to the small holders in developing countries, that is, with a minimum amount of processing &/or transportation of the feedstock beyond the initial harvesting.

Given this economy of effort/cost and the basic growth pattern of much potential feedstock, the design will be of interest to the small to medium low tech, distributed biochar makers in developed regions. These are derivatives of the original Japanese technology and are Top Fed Open Draft FC units and not to be confused with kilns since they do not fit the Standard English definition of kiln.
The Warm Heart team took the basic FC trough concept and, with the support of management, come up with a special FC Trough design which features reduced weight without sacrificing durability and without greatly increasing fabrication cost or difficulty.

This is accomplished by reducing the thickness of the firebox sheet metal and laying out the base and long sides as a single rectangular panel so that the sides are simply bent up from the central base section of the panel at the desired angle.

The ends are inverted isosceles trapezoids congruent with the outline of the bent base and long sides. They are welded on at right angles to the base. This lightweight fire box is cradled in a light weight supporting frame made of box iron (or square iron – iron bars with a hollow square cross section).
To further strengthen the unit and secure the firebox in place, four angle irons encircle the top of the unit with the downward facing arms on the inside of the unit and the opposite arms making the uppermost rim of the unit. Thus the firebox rim is sandwiched between the box iron cradle rim and the angle iron (See schematic details, photos 22 &23).
This basic concept will be referred to as the Warm Heart Trough design.

http://warmheartworldwide.org/new-type-fc-biochar-production-unit/