A coupling device for a sealed coupling of first and second pipe sections, which are movable with respect to one another and at the ends of which respective flanges are fastened to be mutually sealed. The end face of the second flange, which is directed toward the first flange, includes an annular groove and a sealing element is disposed within the annular groove. The annular groove is configured to be subjected to pressure so as to press the sealing element against the end face of the first flange. The sealing element is a sealing ring made of elastic material.