Preheating furnace

Abstract

A preheating furnace having a furnace chamber for preheating an extended metal piece, comprising a transportation means for the metal arranged in the furnace chamber, at least one treatment chamber in the furnace chamber for containing and treating the metal; at least one pressure chamber in the furnace chamber into which hot gas is blown under pressure; and a plurality of rows of slot-type nozzles arranged laterally symmetrically from the metal and extending through a partition which subdivides the furnace chamber into the treatment chamber and the pressure chamber. The slot-type nozzles adduct hot gas to the metal so that warping of the metal is prevented, and the nozzles have elongated openings disposed with the longer axis of each opening transverse to the longitudinal axis of the metal. According to an alternative embodiment of the invention, there is provided a furnace group including a first preheating furnace and a second preheating furnace connected downstream adjacent the first furnace so that the exhaust gases of the second furnace provide hot gases for preheating the metal in the first furnace, wherein at least the first furnace is of the type previously defined above.

Dependencies are inferred from the claim text.