Patent ID: 7993130

Claim:
A method relating to combustion with the aid of a gas burner for furnace heating purposes, the method comprising the steps of: using a gas burner with a burner head ( 1 ) placed at one end of an inner gas pipe ( 2 ), which inner gas pipe is surrounded by an outer protective pipe ( 3 ), an exhaust channel ( 5 ) leading to surroundings, the inner pipe ( 2 ) terminating short of the burner head ( 1 ), a sleeve ( 10 ) located downstream of the burner head, a terminal part ( 17 ) of the sleeve ( 10 ) placed concentrically with the one end of the inner pipe ( 2 ) so that a sleeve orifice ( 13 ) thereof is located within the one end of the inner pipe and a gap ( 14 ) is provided between an inner surface of the inner pipe ( 2 ) and an exterior portion of the terminal part ( 17 ) of the sleeve ( 10 ), the exterior portion of the terminal part ( 17 ) of the sleeve ( 10 ) positioned to co-act with the inner pipe such that said gap ( 14 ) being cylindrical in shape, a size of the gap ( 14 ) defining a mixture of fuel and combustion air coming from the burner head ( 1 ) and re-cycled exhaust gases passing through said gap ( 14 ); flowing fuel gases from the burner head ( 1 ) from inside the inner pipe and inside the outer pipe into the exhaust channel ( 5 ) which leads to the surroundings; and inserting the terminal part ( 17 ) of the sleeve ( 10 ) concentrically within the inner pipe ( 2 ) so that the sleeve orifice ( 13 ) is located within said inner pipe with the gap ( 14 ) provided between the opening ( 15 ) of the inner pipe ( 2 ) and said sleeve ( 10 ), wherein the terminal part ( 17 ) of the sleeve ( 10 ) is inserted at a depth distance within the inner pipe ( 2 ) sufficient so that the exterior portion of the terminal part ( 17 ) of the sleeve ( 10 ) that co-acts with the inner pipe to form said gap ( 14 ) is maintained cylindrical in shape along the depth distance to maintain the size of said gap constant during thermal expansion and at full thermal expansion, and wherein the size of the gap ( 14 ) is caused to be maintained such that the mixture of fuel and combustion air coming from the burner head ( 1 ) and the re-cycled exhaust gases passing through said gap ( 14 ) will be mixed in quantities at which the temperature of combustion will be lower than the temperature in which NO x is formed.