Patent ID: 8297969

Claim:
A combustible gas burner comprising: a main metal body open at a first base end, having a housing for a combustible gas distributor at a second base end and internally lined with a coating of refractory material, and having a volume inside said coating that defines a plenum, an inner central lance for combustible gas arranged inside said main metal body, at least two outer side lances for combustible gas which are disposed within said main metal body, said at least two outer side lances being arranged radially outwardly with respect to said inner central lance, a single duct for the introduction of pre-heated air into said plenum where said single duct is connected to a side surface of said main metal body, said single duct being adapted to bring air into said plenum, said gas distributor associated to said housing for distributing combustible gas to said inner central lance and to said outer side lances, a combustible gas control system for said gas distributor, a refractory unit associated with said first base end, characterized in that said gas burner comprises a series of nozzles situated in said refractory unit for the injection of the pre-heated air into a combustion chamber of an oven, said series of nozzles being in communication with said plenum, said nozzles being located between the inner central lance and the outer side lances, and in that, said combustible gas distributor and control system comprises means for varying a distribution percentage of the combustible gas between the inner central lance and the outer side lances thereby continuously switching from a flame functioning mode of the burner, wherein the combustible gas is injected into said combustion chamber through said inner central lance alone, to a flameless functioning mode, wherein the combustible gas is injected into said combustion chamber through said outer side lances alone wherein said refractory unit comprises a first region, a second region, a third region, which are concentric, said first region in turn comprising a series of calibrated holes and a central hole, having an inner surface from which the gas flows out and which houses a tip portion of said inner central lance where said tip portion has an external diameter, wherein said calibrated holes are positioned between said central hole and said nozzles, a free annular crown being defined between the inner surface of said central hole and the external diameter of said tip portion of the inner central lance said free annular crown being in communication with said plenum thereby allowing the passage of a sufficient quantity of pre-heated air suitable for preventing the overheating of the inner central lance wherein the total outflow section of air from the series of calibrated holes with respect to the total outflow section of air from the series of nozzles has a ratio ranging from 0.01 to 0.9.