Abstract: The device includes a sealing element fixed to the door of a coke oven, the sealing element having an edge forming a junction with the frame of the door, and a channel disposed on the periphery of the sealing element. A sealing gas at a pressure higher than the pressure of the gaseous medium inside the oven flows into the channel. The open side of the channel faces the door frame so as to form a buffer zone of sealing gas sealing off leaks created when the sealing element expands. The channel further includes a plurality of compartments provided with distinct means for supplying the compartments with sealing gas, whereby it is possible to adjust the pressure of the sealing gas in accordance with the places where the leakages are largest.