Abstract: A control sequencing system for a biomass fuel gasification furnace utilizes control vector separation and isolation. The three vector system provides clean operation and fuel efficiency. A wide variety of solid fuel may be used of various fuel values, moisture content, and fuel particle size. The independent control vectors are separated into fan speed, fuel pile level maintenance, and oxygen content maintenance.

Abstract: A relatively level fuel grate surface angle cooperates with multiple feed screws that press solid fuel material into and across the grate surface to continually clear off the grate. Air spaces between each pair of adjacent grate elements for under fire air each have a ninety degree deflector flange at the top of the air space extending from one grate element across the air space and up and over an adjacent grate element to deflect under fire airflow across the adjacent grate element to act as a grate sweeper. The smooth curved surface of the deflector flange between grate elements facilitates movement of the fuel and ash material and prevents from one grate element to the next and prevents clogging of the airflow space.

Abstract: A biomass fuel gasification chamber, blast tube, and heat exchange chamber are interconnected horizontally and subjected to negative drawing pressure by a large variable speed chimney fan. An auger with an air lock feeds biomass fuel automatically into the gasification chamber. Fuel is moved across the gasification chamber on a partially serrated sloping grate. Three stages of fuel activity are created: anaerobic heating for pyrolysis, combustion, and incandescent charcoal oxydation for gasification. A variable speed fan, variable flue, and directional air duct and baffles control the stages with underfire air. A programmed auger in an airtight chamber removes ash automatically. In large systems a hydraulic moving wedge floor assists the fuel feeding auger and a moving sloping grate moves the fuel. A fan and long preheating duct with baffles and fins inside the gasification chamber preheat and direct air into a blast tube leading from the gasification chamber.