Abstract: A burner for a hot-blast furnace has a guidance portion, a channel portion and a mixing portion. The guidance portion serves as an air and gas intake, and is divided into a plurality of separate compartments by thin walled plates. Some of the compartments of the guidance portion have side openings for receiving gas therein, and the other compartments have lower openings for receiving air therein. All of these compartments have exit openings at their top for delivering the air and gas to the channel portion. Conduits are provided in the guidance portion to equalize the pressures within the respective air and gas compartments. The channel portion has a plurality of channels having an overall reduced cross-sectional area of flow as compared with the guidance portion. A mixing portion is disposed above the channels, mixing the air and gas and defining a plurality of burner jets. The reduction in cross-section from the guidance portion increases the velocity of the air and gas going to the burner jets.

Abstract: A recuperator includes plural ceramic recuperator tubes arranged vertically on top of each other. Each tube has an outer periphery, first and second opposite ends, and a gas passage extending longitudinally between such ends. The first end includes an annular sealing surface extending radially inwardly from the periphery and an annular projection defined by a conical surface extending axially from the sealing surface to an end surface of the first end. The second end includes a square flange extending outwardly from the periphery and a stepped seal extending axially inwardly into the flange from an end surface of the second end.

Abstract: Combustion air and fuel gas used for firing blast furnace stoves is preheated by utilizing the heat of waste gases resulting from such firing. The combustion air and fuel gas are passed through respective heat exchangers in heat exchange relationship with the waste gases, thereby preheating the combustion air and fuel gas. The combustion air, after passage thereof through the respective heat exchanger, is further preheated by an externally fired recuperator. The flue gases from the externally fired recuperator are fed to the waste gases before preheating of the combustion air by such waste gases. The external firing of the recuperator is controlled as a function of the final preheated temperature of the thus twice preheated combustion air.

Abstract: A regenerative air preheater includes a masonry casing having therein a combustion chamber and a checker shaft with checker bricks, and a separating wall between the combustion chamber and checker shaft. A space is provided between the separating wall and the checker bricks. Insulating material comprising fireproof fiber material is positioned within the space. The insulating material is structurally free of the separating wall.

Abstract: A shaft casing has a funnel-shaped widened upper portion connected to a cupola casing. Between the widened portion and a refractory shaft lining is a supporting frame having a platform on which a cupola lining rests. The frame is connected to the lower end of the widened portion.