The furnace is cylindrical with a double wall. At least three blowers (12) are mounted to provide a tangential air flow into the burn chamber, which has a grid (162) at the bottom and an upper grid (14) above the burn zone. The exhaust is ducted by a smoke duct (15) into a cylindrical cleaner (20) in which water sprays wash out particulates, which are collected by a series of filters (24). The ash residues are dropped into a conical bottom section (106) of the furnace and from there a screw feed (30) moves the ash into a collecting bin. The fresh waste is fed into the burn chamber by an external chute.
