Self-recuperative burners (or recu-burners) are those where the combustion product is removed from the chamber through the burner, passing through a heat exchanger existent in the burner (CLICK ON IMAGE TO SEE ANIMATION). Therefore, the outgoing gas flows in the outside of the exchanger, countercurrent to the combustion air, which flows in the inside. The combustible gas is supplied via a gas lance and injected into the primary combustion chamber through a nozzle. The ignition and supervision electrodes are central or sideward to the gas lance. Combustion occurs partially inside the ceramic combustion chamber and the flame enters at high speed in the furnace. These burners are widely used in thermal treatment for metals. As combustion air is preheated, these burners ensure greater energy efficiency.