A gas burner for use with a Claus furnace made up of at least five concentric tubes and the spaces formed between them. The diameters of the tubes increase radially outward so that the first tube has a smaller diameter than the fifth tube. At the end of the burner closest to the furnace, the tube ends of the third, fourth, and fifth tubes lie in the same plane. The first and the second tubes are fastened together and capable of movement along the central longitudinal axis of the burner, but their ends closest the furnace are not capable of moving past the plane formed by the third, fourth, and fifth tubes. An injector is located between the first and second tubes at the end closest the furnace. The injector is oriented towards the periphery of the burner.