Ultra low NOx burner

A burner, comprising a hot gas side (21) and an outer zone (22), a primary air feed line (3), a secondary air feed line (1), a fuel feed line (2), wherein,

• the secondary air feed line (1) comprises three concentric cylindrical tubes (an innermost tube (1a), a middle tube (1b) and an outermost tube (1c)), wherein:
• the secondary air feed line (1) protrudes into the hot gas side (21);
• the innermost tube (1a) is open to the outer zone (22) and open to the hot gas side (21);
• the middle tube (1b) is arranged concentrically around the innermost tube (1a) and has a dome-shaped seal (1d), which encloses the innermost tube (1a) on the hot gas side (21) and is closed off towards the outer zone (22);
• the middle tube (1b) comprises overflow channels (1e), which are arranged in the outer zone (22), comprise holes and are open towards the outermost tube (1c);
• the outermost tube (1c) is closed off towards the outer zone (22) and open to the hot gas side (21) and comprises adjustable swirl vanes (1f) near the opening on the hot gas side (21) at an angle of attack of 15° to 80°;
• wherein tube sections (li) are arranged in the dome-shaped seal (1d) of the middle tube of the secondary air feed line (1b), which project through the dome-shaped seal (1d) on one end and project through a baffle plate (1j) on the opposite end;
• the fuel feed line (2) is arranged concentrically around the secondary air feed line (1), which ends immediately after entering the hot gas side (21);
• wherein a first dead volume (4) exists inside the burner between the secondary air feed line (1) and the fuel feed line (2) and
• wherein the fuel feed line (2) has a nozzle construction (5) on the hot gas side (21), which comprises the following:
• a ring diaphragm (5a) with holes (5b);
• radially oriented injector aspiration nozzles (5c), which are in fluid connection with the holes (5b) and, on the aspiration side, project beyond the outer diameter of the primary air feed line (3);
• wherein the holes (5b) in the ring diaphragm (5a) have an angle of attack of 0°-60°,
• wherein the ring diaphragm (5a) forms a truncated cone with an angle of attack of 0°-70°, wherein the base of the cone faces the outer zone (22);
• a second dead volume (9) is arranged between the secondary air feed line (1) and the fuel feed line (2) on the outer side zone (22);
• the primary air feed line (3) is arranged concentrically around the fuel feed line (2), which ends immediately after entering the hot gas side (21) and comprises the following:
• a conical taper of the diameter at the opening on the hot gas side (21), wherein the conical taper forms a truncated cone with an angle of 0°-20°;
• an adjustable ring diaphragm (10) at the opening of the conical taper facing the hot gas side (21);
• swirl vanes (11) with adjustable angle of attack, arranged at an angle of 10° to 90°.