The scheme of the convective circulation furnace with a full cycle of heat exchange for heat treatment of elongated shape products, operating in the mode of periodic change the direction of flow to the opposite. To intensify the process of cooling products through effective supply and remove the coolant from the working area such furnaces used reversing flow devices, consisting of two centrifugal fans, one of which operates on a aerodynamic locking device. Shows the experimental control characteristics reversing flow devices assembled on the basis of various types of centrifugal fans. The data obtained can be used in the development of convection furnaces circulating of heat exchange with the full cycle.