Burner, combustion apparatus, and combustion method

Abstract

A burner includes plural burner ports that produce flames using a first air-fuel mixture and plural auxiliary burner ports that are disposed in a circumference of the burner ports, the plurality of the auxiliary burner ports producing an auxiliary flame using a second air-fuel mixture whose an air ratio is different from an air ratio of the first air-fuel mixture. The air ratios of the first air-fuel mixture and the second air-fuel mixture are each higher than 1.

What is claimed is: 
     
         1 . A burner comprising:
 a plurality of burner ports that produce flames using a first air-fuel mixture; and   a plurality of auxiliary burner ports that are disposed in a circumference of the burner ports, the plurality of the auxiliary burner ports producing an auxiliary flame using a second air-fuel mixture whose an air ratio is different from an air ratio of the first air-fuel mixture, wherein   the air ratios of the first air-fuel mixture and the second air-fuel mixture are each higher than 1.   
     
     
         2 . The burner according to  claim 1 , wherein
 the auxiliary flame produced by the plurality of the auxiliary burner ports is unified to surround the flames, and the auxiliary flame combusts at a position lower than a combustion position of the flames to hold the flames.   
     
     
         3 . The burner according to  claim 1 , wherein
 a flow velocity of the first air-fuel mixture is higher than a flow velocity of the second air-fuel mixture.   
     
     
         4 . The burner according to  claim 1 , wherein
 a gas flow ratio of the first air-fuel mixture supplied to the burner ports to the second air-fuel mixture supplied to the auxiliary burner ports is set to be at a ratio of 80 to 20 or a ratio in vicinity thereof.   
     
     
         5 . The burner according to  claim 4 , wherein
 air of an amount calculated based on a supplied gas amount or the gas flow ratio is supplied to the auxiliary burner ports for a set air-fuel mixture amount.   
     
     
         6 . A combustion apparatus comprising a plurality of burner units, wherein the plurality of the burner units each comprise:
 a plurality of burner ports that produce flames using a first air-fuel mixture; and   a plurality of auxiliary burner ports that are disposed in a circumference of the burner ports, the plurality of the auxiliary burner ports producing an auxiliary flame using a second air-fuel mixture whose an air ratio is different from an air ratio of the first air-fuel mixture, and wherein   the air ratios of the first air-fuel mixture and the second air-fuel mixture are each higher than 1.   
     
     
         7 . A combustion method comprising:
 producing flames at a plurality of burner ports using a first air-fuel mixture whose an air ratio is higher than 1; and   producing an auxiliary flame at a plurality of auxiliary burner ports disposed in a circumference of the burner ports using a second air-fuel mixture whose an air ratio is higher than 1, the air ratio of the second air-fuel mixture being different from the air ratio of the first air-fuel mixture.