The object is to provide a burner capable of taking in sufficient primary air even though the size thereof is compact, and capable of being used as an all-primary air burner. A burner includes a mixing pipe to which a fuel gas and combustion air are supplied, a burner main body having a mixing chamber at a top end on a downstream side of the mixing pipe, and a burner head which is provided at an upper part of the burner main body while communicating with the mixing chamber and has first and second burner ports for ejecting mixed gas of the fuel gas and air for combustion mixed in the mixing chamber. The burner further includes an extension pipe in the burner main body protruding inside the mixing chamber being formed by extending the mixing pipe.
1. A burner comprising:
a burner main body having a mixing pipe being supplied with a fuel gas and air for combustion, and provided with a mixing chamber at a downstream end side of the mixing pipe; and
a burner head provided at an upper part of the burner main body while communicating with the mixing chamber, and having burner ports for ejecting a mixed gas of the fuel gas and combustion air mixed in the mixing chamber,
wherein an extension pipe is protruded into the mixing chamber by extending the mixing pipe,
wherein the extension pipe is positioned inside the mixing pipe and an end thereof extends through and beyond an end of the mixing pipe inside the mixing chamber, and
wherein a bottom surface of said end of the extension pipe is flattened and said flattened surface is in contact with a bottom surface of the mixing chamber, whereby said contact between said flattened surface of the end of the extension pipe and said bottom surface of the mixing chamber prevents the extension pipe from rotating within the mixing chamber, wherein the protruded end of the extension pipe is cut to be continuously inclined, so as to have an upwardly extending opening.
2. The burner according to claim 1 , wherein the burner head formed is a cylindrical shape having a plurality of burner ports bored on almost the entire periphery of a vertical side surface thereof, whereby said cylindrical shape is positioned right above the mixing chamber of the burner main body.
3. The burner according to claim 1 , wherein the extension pipe is held by the mixing pipe inside the mixing chamber.
4. The burner according to claim 2 , wherein the extension pipe is held by the mixing pipe inside the mixing chamber.
5. The burner according to claim 1 , wherein the mixing chamber, from a top plan view, is formed in a shape that is substantially round.
6. The burner according to claim 5 , wherein said cylindrical shape of the burner head, from a top plan view, is substantially centered and in communication with the center of the round mixing chamber.
7. The burner according to claim 1 , wherein the mixing chamber has upper and lower internal edge corner surfaces, and
wherein said upper and lower internal edge corner surfaces are formed into a substantially rounded convex shape.