Abstract: A vortex burner is provided in a burner block, having a sleeve spaced within the burner block, the sleeve being shorter than the burner block opening and spaced within such opening to provide a passageway between them. The burner block has an exvoluting cup which creates negative pressure therein, tending to draw cooling air inwardly into the cup, cooling the short sleeve.

Abstract: Methods and apparatus for regulating furnace combustion air flow are provided which measure a gaseous combustion product in furnace gas after combustion, generate a present signal responsive to the measurement and change flow rate of combustion air in response to the generated signal in a manner the same as flow rate was changed in response to a previously generated signal if the present signal relates to the previous signal in the manner the previous signal related to a signal ancestor thereto but change the flow rate of combustion air in response to the generated signal in a manner opposite the manner the flow rate was changed in response to the previously generated signal if the present signal relates to the previous signal in a manner opposite the manner the previous signal related to a signal immediately ancestor thereto.