Pellet burning stoves have been found to be extremely efficient combustors with the predictable nature of the pellet fuel and the ability to control burning conditions within the fire box enclosures of such units. Combustion efficiency, due to the consistent size, material, and moisture content of the combustible particulates, may be controlled by specific design of the air feed systems and burn pots into which the pellets are fed in metered quantitites.
Combustion efficiency at high burn rates is a relatively easily achieved objective, due to the burn intensity and the ability to supply regulated combustion air to the burning product. Combustion efficiency at lower burn rates, however, is more difficult to achieve. Previous burn pots having a fixed internal volume must be designed for a maximum load of particulate fuel, thereby detracting from combustion efficiency at low burn rates. Such "typical" burn pots are excessively large for small amounts of fuel at low burn settings. A difficulty experienced at low burn is that the small amounts of fuel received within the burn pots is spread over a considerable surface area, leaving the individual combustible particulates to burn independently. Even with the fairly consistent nature of the combustible particulates, the individual particulates cannot be relied upon to burn evenly individually. Some will burn actively while others smolder or do not burn at all. A need has therefore remained for a burn pot in which provisions are made to facilitate high burn rates and that it will also function well to increase effective burning at low burn rates by accumulating the particulates in a desired mass.
Another difficulty with existing forms of burn pots is ash accumulation. This is especially true of certain combustible particulates that do not burn completely and leave excessive ash. The task of cleaning ash from the burn pots thus becomes a tedious chore. There therefore also remains a need for a burn pot that includes provision for cleaning ash and cinders from the burning area.