Recuperative burner

Abstract

A recuperative burner having a burner base and a combustion chamber tube in which at least one burner nozzle is positioned. An exhaust gas recirculation device has a jet pump operated by combustion air and comprises a jet nozzle. A jet pump annular gap is provided for the intake of exhaust gases from outside the combustion chamber tube via an annular driving jet. The exhaust gas recirculation device being configured upstream of the mixing plane of the fuel gases flowing into the combustion chamber tube, between the burner base and the combustion chamber tube and comprises at least one endless exhaust gas intake opening and/or a peripheral, self-contained arrangement of a plurality of exhaust gas intake openings, from which at least one flow path leads into the interior of the combustion chamber tube. A recuperator is arranged upstream of the combustion chamber tube and has a heat transfer body.

What is claimed is: 
     
         1 . A recuperative burner comprising:
 a burner base;   a combustion chamber tube, in which at least one burner nozzle is positioned, at which at least one fuel gas line opens;   an exhaust gas recirculation device with a jet pump which is operated by combustion air and comprises a jet nozzle, a cross section of which decreases in a flow direction, and comprises a jet pump annular gap for an intake of exhaust gases from outside a combustion chamber tube via an annular driving jet, the exhaust gas recirculation device being configured upstream of a mixing plane of the fuel gases flowing into the combustion chamber tube, between the burner base and the combustion chamber tube;   at least one endless exhaust gas intake opening and/or a peripheral, self-contained arrangement of a plurality of exhaust gas intake openings, from which at least one flow path leads into an interior of the combustion chamber tube; and   a recuperator arranged upstream of the combustion chamber tube, with a heat transfer body which has at least two separate throughflow channels provided to conduct counterflowing fluids,   wherein at least two fluids enter/exit via inlet and outlet openings of the throughflow channels in the heat transfer body and, of the fluids, one is formed by combustion air to be preheated and the other is formed by the exhaust gas of the recuperative burner, and   wherein the jet nozzle is formed at a combustion air outlet opening of the recuperator.   
     
     
         2 . The recuperative burner according to  claim 1 , wherein the base is connected to an inner tube with an inner cavity, which is passed through the combustion chamber tube and/or through the heat transfer body, wherein the combustion air outlet opening of the combustion air throughflow channel extends around the outside of the inner tube, wherein the nozzle of the jet pump is formed inwards by the inner tube and externally by the conical nozzle ring, a tapered end of which is extended to the outside of the inner tube, wherein, between the inner tube and the nozzle ring, the jet pump annular gap is formed, and wherein at least one exhaust gas inlet opening for the exhaust gas throughflow channel of the combustion chamber tube and/or the heat transfer body is arranged outside the nozzle ring. 
     
     
         3 . The recuperative burner according to  claim 1 , wherein the inner tube opens into or at an inlet opening of an eductor which is expanded in diameter relative to the combustion chamber tube, to which the combustion chamber tube is connected, and wherein, between the outside of the inner tube and the edge of the inlet opening of the eductor, the annular exhaust gas intake opening is formed. 
     
     
         4 . The recuperative burner according to  claim 1 , further comprising an inner tube with an inner cavity that is passed through the heat transfer body, wherein the jet pump annular gap and the exhaust gas intake opening are formed in a section of the inner tube located within the heat transfer body. 
     
     
         5 . The recuperative burner according to  claim 4 , wherein in the inner cavity, a conical combustion chamber tube with a trumpet-shaped burner mouth element is arranged, which extends to the front face of the heat transfer body, wherein a flow reversal chamber is formed between the outlet openings of the throughflow channels serving as air supply ducts and the burner mouth element, wherein, between an inner wall of the heat transfer body and an outer wall of the combustion chamber tube, an annular nozzle gap is formed, to which a jet pump annular gap is connected which widens in cross section in the flow direction, wherein, from the exhaust gas intake openings on the outside of the heat transfer body a first flow path leads directly into the jet pump annular gap and a further path leads into one of the throughflow channels in the heat transfer body serving as an exhaust extraction duct, and wherein the jet pump annular gap extends to a deflection point at the rear, open end of the combustion chamber tube. 
     
     
         6 . The recuperative burner according to  claim 5 , wherein the burner mouth element connects to the heat transfer body such that it is positioned in front of inner mouth openings of the throughflow channels serving as air supply ducts and the external exhaust gas intake openings on the heat transfer body are exposed outside the burner mouth element. 
     
     
         7 . The recuperative burner according to  claim 5 , wherein recesses are provided on the burner mouth element in an area of the flow reversal chamber. 
     
     
         8 . The recuperative burner according to  claim 1 , wherein the mouth of the jet pump annular gap is positioned within the cross section of the endless exhaust gas intake opening or within the closed arrangement of a plurality of exhaust gas intake openings. 
     
     
         9 . The recuperative burner according to  claim 1 , wherein the jet pump annular gap and/or the exhaust gas intake opening each has a meandering course. 
     
     
         10 . The recuperative burner according to  claim 1 , wherein an additional exhaust gas recirculation device is provided with a jet pump which is operated by a mixture of fuel gas, combustion air and the recirculating exhaust gas obtained from the jet pump of the first exhaust gas recirculation device and which is formed downstream of the mixing plane of the fuel gases flowing into the combustion chamber upstream of the mouth of the combustion chamber tube. 
     
     
         11 . The recuperative burner according to  claim 10 , wherein the further exhaust gas recirculation device is arranged in the flow direction upstream of a burner nozzle cone of the burner and is arranged with the combustion chamber tube in a common jet tube. 
     
     
         12 . The recuperative burner according to  claim 10 , wherein the additional exhaust gas recirculation device comprises a venturi nozzle module, the inlet opening of which is arranged behind the burner nozzle cone. 
     
     
         13 . The recuperative burner according to  claim 10 , further comprising at least one segmented flame tube arranged downstream behind the venturi nozzle module in the jet tube.