Abstract: A sealing device for insertion in a flanged pipe coupling comprises a split ring with an annular sealing member seated in a groove in one axially facing side of the ring. At intervals around the ring there are screws which project radially inwardly into the base of the groove to co-operate with the concealed face of the sealing member. This face and the adjacent screw ends combine in a wedging or camming action as the screws are turned to urge the sealing member out from the groove. When placed between the flanges of a pipe coupling this action forms an effective seal which can be completed by injecting sealing compound through the ring. The ring, if not the sealing member, is re-usable if the seal has to be broken.