Abstract: A ring section furnace for the calcination of carbon bodies, has a number of chambers (K1-Kn) in which the carbon bodies are placed when performing the calcination process. During the calcination process, a part of the furnace comprising a minor number of chambers is divided into a preheating zone (K3-K2), a combustion zone (K7-K14), and a cooling zone (K8-K10) that together in a successive manner, are advanced relative to the furnace. Flue gases formed under the process are sucked out from the first chamber (K2) in the preheating zone through a pipe connection to a common ring duct (10). To eliminate the entrance of false air from the first chamber (K1) adjacent the preheating zone, a counterpressure fan (17) is arranged in connection with the first chamber (K1).