Flat burner

Abstract

A flat burner has a mixing tube portion with an inlet port of a cross section elongated in a vertical direction and a throat portion lying adjacent to a back of the inlet port and having a cross section smaller than that of the inlet port. A distribution chamber portion introduces a mixture of a fuel gas ejected from a gas nozzle disposed to face the inlet port and primary air flowing from the inlet port. The throat portion is formed at a position in which a sectional center thereof is offset in one of the upward and downward directions relative to a sectional center of the inlet port. The gas nozzle is disposed such that an axis of the nozzle hole of the gas nozzle passes through a vertical position that is offset from the sectional center of the throat portion toward the sectional center of the inlet port.

What is claimed is: 
     
         1 . A flat burner having, at an upper end thereof, a rectangular flame port portion, the flat burner comprising a mixing tube portion and a distribution chamber portion,
 the mixing tube portion having: an inlet port of a cross section elongated in a vertical direction where a longitudinal direction of the flame port portion is defined as a back-and-forth direction; and a throat portion lying adjacent to a back of the inlet port and having a cross section smaller than that of the inlet port,   the distribution chamber portion introducing, from the mixing tube portion into the flame port portion, a mixture of a fuel gas ejected from a gas nozzle disposed to face the inlet port and primary air flowing from the inlet port;   wherein the throat portion is formed at a position in which a sectional center thereof is offset in one of the upward and downward directions relative to a sectional center of the inlet port, and   wherein the gas nozzle is disposed such that an axis of a nozzle hole of the gas nozzle passes through a vertical position that is offset from the sectional center of the throat portion toward the sectional center of the inlet port.   
     
     
         2 . The flat burner according to  claim 1 , in which a connecting portion between the mixing tube portion and the distribution chamber portion is positioned backward of a longitudinal center of the flame port portion,
 wherein the sectional center of the throat portion is offset downward relative to the sectional center of the inlet port.