Burner and boiler equipped with burner

Abstract

A burner ( 10 ) includes a main combustion unit ( 20 ) configured to combust preliminary mixture gas obtained by mixing fuel gas and air at a first air ratio, and a plurality of flame stabilizing units ( 30 ) located to interpose the main combustion unit ( 20 ) and configured to combust preliminary mixture gas of a second air ratio that is lower than the first air ratio and achieves stable formation of flame.

1 . A burner comprising:
 a main combustion unit configured to combust preliminary mixture gas obtained by mixing fuel gas and air at a first air ratio; and   a plurality of flame stabilizing units located to interpose the main combustion unit and configured to combust preliminary mixture gas of a second air ratio that is lower than the first air ratio and achieves stable formation of flame.   
     
     
         2 - 5 . (canceled) 
     
     
         6 . The burner according to  claim 1 , further comprising:
 a first supply line configured to supply the flame stabilizing units and the main combustion unit with the preliminary mixture gas of the second air ratio; and   a second supply line configured to supply the main combustion unit with air, wherein   the main combustion unit and the flame stabilizing units are provided as areas where the preliminary mixture gas is combusted, and are disposed on a downstream side of the first supply line and the second supply line.   
     
     
         7 . The burner according to  claim 6 , wherein:
 the first air ratio is from 7% to 11% when converted to a concentration of exhaust gas O 2 , and   the second air ratio is from 6% to 10% when converted to the concentration of exhaust gas O 2 .   
     
     
         8 . The burner according to  claim 7 , wherein:
 the main combustion unit includes a plurality of divisional main combustion units, and   the flame stabilizing units are located to interpose each of the divisional main combustion units.   
     
     
         9 . The burner according to  claim 6 , wherein:
 fuel gas supplied to the main combustion unit is from 50% to 95% in volume of fuel gas supplied to the burner, and   fuel gas supplied to the flame stabilizing units is from 5% to 50% in volume of the fuel gas supplied to the burner.   
     
     
         10 . The burner according to  claim 8 , wherein
 fuel gas supplied to the main combustion unit is from 50% to 95% in volume of fuel gas supplied to the burner, and   fuel gas supplied to the flame stabilizing units is from 5% to 50% in volume of the fuel gas supplied to the burner.   
     
     
         11 . A boiler comprising:
 a boiler body;   a plurality of water pipes disposed in the boiler body and extending vertically;   a lower header disposed below the plurality of water pipes;   an upper header disposed above the plurality of water pipes; and   a burner having a main combustion unit configured to combust preliminary mixture gas obtained by mixing fuel gas and air at a first air ratio that is from 7% to 11% when converted to a concentration of exhaust gas O 2 , and a plurality of flame stabilizing units configured to combust preliminary mixture gas of a second air ratio that is from 6% to 10% when converted to the concentration of exhaust gas O 2  and achieves stable formation of flame.   
     
     
         12 . The boiler according to  claim 11 , comprising:
 a first supply line configured to supply the flame stabilizing units and the main combustion unit with the preliminary mixture gas; and   a second supply line configured to supply the main combustion unit with air.   
     
     
         13 . The boiler according to  claim 12 , wherein
 fuel gas supplied to the main combustion unit is from 50% to 95% in volume of fuel gas supplied to the burner, and   fuel gas supplied to the flame stabilizing units is from 5% to 50% in volume of the fuel gas supplied to the burner.