Output A few kW for 4 to 8 hours with an air door opening 20 to 30 mm. The burn rate increases near the end of the sawdust charge, as the burning core expands out to reach the inner container walls. Up to 7 kW can be produced, but at this output the case glows red-hot, so inflammables must be kept well away, and the fuel charge does not last long. Figure 2: Removable inner bin with hole through to air chamber below (H Bland)
[top] [end]Operation The heater comprises two concentric bins. The removable inner bin has a hole through the bottom to the air chamber below. This allows hot gases to be drawn upwards through the hole to where combustion occurs. The hot gases are then drawn downwards between the inner and outer walls of the heating stove, providing good heat exchange to the room as they pass between the two chambers before passing out of the room through a flue (Figures 1 & 2).
[top] [end]Fuel range Sawdust is best. Shavings or chip-pings will work provided they do not collapse down the airway. They work better mixed with sawdust, but have the effect of making it burn faster and hotter.