Patent ID: 7647898
Filing Date: 2010-01-19
Classification: F23C,F23D,F24H

Abstract:
1. A boiler comprising: a premixing portion including a first fuel supply portion that supplies fuel gas to the premixing portion to be mixed with air to form a first premixed gas; a premixed gas burner that receives the first premixed gas from the premixing portion and ejects the first premixed gas into a boiler chamber where it is subject to a combustion reaction, the boiler chamber having water tubes at a predetermined angle and in close proximity to the premixed gas burner; and a second fuel supply portion that supplies at least one of fuel gas and premixed gas into the boiler chamber at a position spaced apart by a predetermined distance from the premixed gas burner where it is also subject to a combustion reaction, wherein the premixed gas ejected from the premixed gas burner has an air ratio which satisfies the following relational expression: