A FURNACE STRUCTURE, A METHOD FOR BURNING WOOD AS WELL AS A METHOD FOR RETRIEVING COMBUSTION HEAT

摘要

The invention relates to a furnace structure for burning of wood, said structure comprising a combustion chamber (1) including a grate (2) and an inlet (7, 23) for secondary air (12, 22), an after combustion space (9, 14), located above said combustion chamber, and a smoke conduit (30, 32) connected thereto. The structure comprises a combustion conduit (14, 25) which is designed in compliance with an essentially uniform laminar velocity of flow for said combustion gas (10, 15), said combustion conduit (14, 25) constituting an integral after combustion space and smoke box having guiding and heat transferring means (16, 17, 29) of a low heat capacity, said means changing the orientation of said combustion gases first in a horizontal direction and, thereafter, in a vertical direction. The invention further relates to a method for burning of wood, wherein exhausting combustion gases (10, 15) are retained in an integral hot zone (14, 25) in a furnace by controlling the amout of air (2, 12, 22) fed into a combustion chamber (1), while internally stirring said combustion gases (10, 15) by changing the essential orientation of the combustion gases/flames (10, 15, 8) immediately above said combustion chamber (1). The invention further relates to a method for recovering heat from hot combustion gases (15), which gases are initially conducted downwards in a first conduit (25) and upwards in a conduit (30) on the outside thereof.