Premix burner with mixing section

1. A burner arrangement comprising:

a premix burner for a heat generator generating a swirl flow, the premix burner having sectional conical shells which complement one another to form a swirl body, the shells enclosing a conically widening swirl space and mutually defining tangential air-inlet slots;

fuel feeds for at least a first fuel, distributed along the tangential air-inlet slots, the fuel feeds including at least one fuel feed for a second fuel, the at least one fuel feed for a second fuel being arranged along a burner arrangement axis passing centrally through the swirl space;

a transition piece assisting or maintaining the swirl flow directly connected to the premix burner downstream of the swirl body;

a mixing tube directly connected to and downstream of the transition piece, the mixing tube having an axial downstream end; and

at least one additional fuel feed positioned

centrally in a region of the mixing tube relative to the mixing tube axial downstream end, or upstream of the mixing tube axial downstream end;

wherein the mixing tube is configured and arranged to receive a mixture formed within the premix burner, and wherein the at least one additional fuel feed is configured and arranged to inject fuel into said mixture.

2. The burner arrangement as claimed in claim 1 , wherein the at least one additional fuel feed is oriented at an angle α, with 90°<α<180°, where αconstitutes an intersection angle at which the fuel introduced into the swirl space, in the region of the transition piece and/or the mixing tube, intersects the burner arrangement axis.

3. The burner arrangement as claimed in claim 1 , wherein the at least one additional fuel feed includes at least two fuel nozzles configured and arranged to discharge fuel while forming a fuel spray.

4. The burner arrangement as claimed in claim 3 , wherein the at least two fuel nozzles are arranged axially symmetrically relative to the burner arrangement axis.

5. The burner arrangement as claimed in claim 3 , wherein the at least two fuel nozzles lie in a cross-sectional plane which perpendicularly intersects the burner arrangement axis.

6. The burner arrangement as claimed in claim 1 , wherein the at least one additional fuel feed is positioned in the region of the swirl body and comprises at least two fuel nozzles arranged symmetrically relative to the burner arrangement axis and which are each integrated in or at the sectional conical shells.

7. The burner arrangement as claimed in claim 1 , wherein the at least one additional fuel feed is positioned in the region of the transition piece and comprises at least two fuel nozzles arranged symmetrically relative to the burner arrangement axis and centrally relative to an axial length of the transition piece or upstream thereof.

8. The burner arrangement as claimed in claim 1 , wherein the at least one additional fuel feed is positioned in the region of the mixing tube and comprises at least two fuel nozzles arranged symmetrically relative to the burner arrangement axis.

9. The burner arrangement as claimed in claim 8 , wherein the mixing tube comprises an axially extending inner wall diffuser contour having a cross section of flow narrowing in the direction of flow, a smallest cross section of flow, and an increasing cross section of flow; and

wherein the at least two fuel nozzles are positioned in the region of the smallest cross section of flow.

10. The burner arrangement of claim 1 , wherein the at least one additional fuel feed is positioned at the mixing tube wall.

11. The burner arrangement of claim 10 , wherein the at least one additional fuel feed defines and axis which intersects a longitudinal axis of the burner.