Abstract: A vulcanizing device in which a member is enclosed in an extruder device and the enclosed member is vulcanized at a predetermined pressure in a vulcanizing tube connected to the extruder device, wherein the vulcanizing tube is placed at a distance from the extrusion device, a sealing device is positioned directly before and coaxially to the vulcanizing tube, the length of the sealing device being less than the said distance, the sealing device contains a sealing housing, whose interior has spaced radial guiding elements which have coaxial openings for the passage of the enclosed member and divide the interior of the sealing housing into individual chambers lying axially behind each other, the sealing housing has an inlet opening between the ends, which is connected as a locking medium to a source, of which the pressure is arranged to be somewhat higher than the pressure in the vulcanizing tube, and the chambers are connected to outlet openings in the sealing housing, which are connected to throttled discharge