Gas furnace

A gas furnace, comprising:

• a mixer that mixes air and a fuel gas, which are introduced through an intake pipe and a manifold, respectively, to form a mixture;
• a mixing pipe through which the mixture, having passed through the mixer, flows;
• a burner assembly that produces a combustion gas by burning the mixture having passed through the mixing pipe;
• a heat exchanger through which the combustion gas flows;
• an exhaust pipe through which an exhaust gas, as the combustion gas having passed through the heat exchanger, is discharged outside of the gas furnace;
• and
• an inducer that induces a flow of a fluid through the intake pipe, the mixer, the mixing pipe, the burner assembly, the heat exchanger, and the exhaust pipe, wherein the mixer has a front end connected to the intake pipe, a rear end connected to the mixing pipe, and a side surface connected to the manifold, wherein the mixer comprises a mixer housing forming an exterior of the mixer and a venturi tube disposed inside of the mixer housing, wherein the venturi tube comprises:
• a throat having at least one fuel inlet hole, through which the fuel gas having passed through the manifold is introduced, and which is formed on at least a portion of a side surface of the throat, and at least one flange which extends outwards from an outer circumferential surface of the venturi tube, to be pressed against an inner circumferential surface of the mixer housing, wherein the at least one fuel inlet hole is formed at a position corresponding to a space between the flange and a connection portion of the manifold to the mixer housing with respect to a longitudinal direction of the venturi tube;
• a converging section having on one end an air inlet, through which the air, having passed through the intake pipe, is introduced;
• and
• a diverging section which is connected to the throat, and in which the air and the fuel gas, having passed through the converging section and the at least one fuel inlet hole, respectively, are mixed and flow as a mixture, and which has on one end a discharge port through which the mixture is discharged to the mixing pipe, wherein the throat is connected to the converging section, and wherein the at least one fuel inlet hole comprises a plurality of fuel inlet holes spaced apart from each other at predetermined intervals in a circumferential direction of the throat.