Abstract: A sealing device on a pipe includes an elastic sealing ring of generally U-shaped cross-section, which is clamped on the pipe by a clamping strap. The U-flanges of the sealing ring are so loaded by the pressure exerted by the clamping strap on the U-web of the sealing ring as to occupy a substantially radial position.

Abstract: A method for fastening an elastic sealing ring on a pipe includes the steps of applying a base portion of the sealing ring against the circumferential surface of the pipe, and placing a clamping strap under tension around the outer face of the base portion. The clamping strap is secured to the pipe by spot-welding in at least two welding spots, the spot-welding operation being carried out with the material of the sealing ring located between the clamping strap and the pipe. A device for fastening the sealing ring on the pipe is provided which comprises, in addition to the clamping-strap supply, a movable assembly for feeding the clamping strap to the pipe; an assembly for applying the strap on the base portion of the sealing ring; a unit for spot-welding the clamping strap to the pipe; and a friction-exerting mechanism for gripping and exerting a braking action on the clamping strap.