Importance

Loading Importance Indicators...

Abstract

A method and apparatus for preheating a furnace during a warm-up phase of furnace operation. The furnace has main burners with a tubular fuel supply surrounded by a main combustion air duct defining an annular space between the supply and the duct that extends in an axial direction of the main burner. A pilot nozzle in the annular space extends in an axial direction of the burner towards an interior of the furnace and discharges readily ignitable fluid fuel jets through orifices in the nozzle toward the interior of the furnace. Combustion air from the duct is directed past the nozzle and is mixed with the fuel discharged from the orifices to form an ignitable mixture that is ignited to form the furnace heating pilot flame downstream of the nozzle. The flame is stabilized and anchored to the pilot nozzle by recirculating portions of the flame and its constituents from the furnace interior back towards the nozzle by protecting the air passing through the primary ignition zone from being directly affected by air flowing through the main combustion air conduit, diverging the fuel jets relative to the axial direction by an angle between about 20° to 80°, and giving the fuel jets a tangential directional component relative to the axial direction to spin the flame about the axis of the pilot.

Loading the Abstract Image...

First Claim