Solid fuel heating appliance

A domestic or small industrial heating appliance fired by solid fuel, comprising;

• a rotary furnace vessel to contain a fire of the fuel and having a bottom inlet for the fuel, said vessel including a wall part above said bottom inlet with holes for the admission of combustion air provided in said wall part;
• vessel drive means to drive said vessel in rotation around a generally upright axis during at least part of the time when said vessel is in use;
• fuel supply means for delivering the solid fuel to said bottom inlet of said furnace vessel;
• a stationary enclosure surrounding said furnace vessel and spaced from said furnace vessel to define an air space between said furnace vessel and said enclosure, said enclosure comprising a stationary water jacket surrounding at least an upper region of said furnace vessel so as to absorb heat therefrom and cool at least an upper region of said furnace vessel, said water jacket being spaced from said furnace vessel so that said air space extends between said furnace vessel and said surrounding water jacket;
• means to force combustion air to flow into said air space and thereafter into said furnace vessel through said holes therein;
• and
• an air seal interposed between said water jacket and said upper region of said furnace vessel above said holes in said furnace vessel, said air seal extending outwardly from said furnace vessel, to said water jacket to define an upper boundary of said air space and constraining outflow of air from said air space to pass through said holes into the furnace vessel, said air seal comprising at least one moving flange fast with the furnace vessel and projecting therefrom and a co-operating stationary member fast with and projecting from said water jacket and lying face to face against said flange whereby both said stationary member and said moving flange are cooled by said water jacket absorbing heat therefrom, the moving flange and stationary member having apertures positioned so that the apertures in said moving flange and said stationary member periodically come into register during rotation of the furnace vessel, and then permit ash to fall through the apertures into said air space.